Quantitative and qualitative effects of proteins and...

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EurAsian Journal of BioSciences

Eurasia J Biosci 14, 915-932 (2020)

Quantitative and qualitative effects of proteins and natural sugars on hardening and color of high-protein nutrition bars during storage

Sami Kadhim Hassan 1*

1 College of Biotechnology, University of Al-Qadisiyah, IRAQ *Corresponding author: [email protected]

Abstract Unpalatably, high protein nutrition (HPN) bars tend to go hard during storage. The present study aims to investigate the effects of quantity (34%, 36%, 38%, 40%, and 45%) and quality of milk proteins: whey protein isolate (WPI) and milk protein concentrate (MPC) or a mixture of them with alcohol sugar syrups (sorbitol + glycerol), natural sugar syrups (agave, rice and honey) and glycerol combined with vegetable shortening oil on the hardness, water activity and color change in bars after accelerated storage at 35°C for 43 days in order to meet consumer demands; such as soft HPN bars and high level of protein combined with natural sugar syrups. Using MPC makes the bars brittle and crumbly. Using glycerol initially makes bars softer but accelerates hardening. Using mixture of 50:50 WPI and MPC and 80% sorbitol, agave, rice or honey mixed with 20% glycerol in bars formulations improve its cohesiveness and textural stability, and minimize bars hardness with fold minimizing (F.M) as follows: 10.4, 5.4, 1.2 and 5.8 fold of 34% protein, 7.8, 4.0, 1.1 and 4.5 fold of 36% protein, 5.0, 3.1, 1.1 and 5.0 fold of 38% protein, 4.7, 3.2, - and 5.0 fold of 40% protein, and 5.9, 4.7, - and 5.9 fold of 45% protein respectively. Hardening of HPN bars during storage was related to protein surface-solvent interactions by non-covalent interactions (hydrogen bonds and van der Waals and ionic forces not by disulphide bonds or browning reactions or water activity) with the protein layers would be with the hydroxyl groups of sugars especially of glycerol and its functioning of hydrophobic interactions between the hydrophobic layers of protein in HPN bars will tend to aggregate together resulting the hardness in bars. Keywords: milk protein, WPI, MPC, alcohol sugars, natural sugars, HPN bar, hardening, water activity, color Hassan SK (2020) Quantitative and qualitative effects of proteins and natural sugars on hardening and color of high-protein nutrition bars during storage. Eurasia J Biosci 14: 915-932. © 2020 Hassan This is an open-access article distributed under the terms of the Creative Commons Attribution License.

Practical Application

Hardening of HPN bars occurs when an extensive

protein network structure develops so using ingredients

of 34% - 45% mixture of milk proteins of 50:50 WPI and

MPC and 80% of sorbitol sugar syrup or natural sugar

syrups of agave or honey mixed with 20% glycerol and

combined with vegetable shortening oil in HPN bars

formulations improve its cohesiveness and textural

stability, and minimize bars hardness and extend

sensory shelf life of such dairy products for consumer, in

addition meeting consumer demands of HPN bar with

high protein levels.

INTRODUCTION

High-protein nutrition (HPN) bars are intermediate-

moisture foods have water activity between 0.5-0.8 and

used as part of the sports nutrition, muscle building,

health supplement and others (Liu and others 2009) and

before few years HPN bars reflecting the concern of

people to have a healthier life style. In general, HPN bars

composed from three main ingredients: 1. About 20-50%

protein (milk protein powder such as whey protein

isolate, milk protein concentrate, hydrolyzed whey

protein isolate, whey protein isolate, whey protein

concentrate, and other proteins include soy protein

isolate, egg white proteins, and others), 2. About 20-

50% sugar alcohols sweeteners and plasticizer such as

(sorbitol, glycerol, xylitol, maltitol, erythritol, mannitol,

isomalt, lactitol) and others like high fructose corn syrup,

and 3. About 10-20% lipid to provide malleability of bars

(vegetable shortening oil, cocoa butter, coconut butter,

palm, canola and soy oils, and others) in addition to the

main components, chocolate, flavorings, nuts, wafers,

nuggets and vitamins and minerals are often added for

enhanced nutritional value.

Received: August 2019

Accepted: March 2020

Printed: April 2020

mailto:[email protected]

EurAsian Journal of BioSciences 14: 915-932 (2020) Hassan

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The water activity (Aw) of most HPN bars is between

0.5- 0.8, in the reactive rang for Maillard browning

reaction between amino groups of amino acids and

carbonyl groups of reducing sugars, and the critical

micro level of water activity is 0.65- 0.75 (Labuza et al.

2010). HPN bars are generally made to have water

activity less than 0.65 (Loveday et al. 2009, Hassan

2015) and some have water activity reach to 0.3

(Doherty and Ward 1997, Hassan 2015), low water

activity in bars is required to inhibit microbial growth

since many HPN bars are manufacture without heat

treatment (Liu et al. 2009). The moisture content of HPN

bars is from 10% to 15% w/w (Zhu and Labuza 2010).

Alcohol sugar syrups such as sorbitol syrup contain

about 70% solid works to collect bar components

together and 30% water act as solvent. Natural sugar

syrups such as agave syrup and honey containing about

20% water, while rice syrup containing about 30% water.

The shelf life of high protein nutrition bars is maintain

stable for about six months at room temperature and

often limited the development of a ‘hard’ or ‘tough’

texture that consumers find unpalatable (Gautam et al.

2006, Hassan 2015, McMahon et al. 2009), but stability

for greater than 12 months is desired (Imtiaz et al. 2012,

Hassan 2015). Hardening of bars depends on type and

level of protein and sugars, this hardening occurs

without any moisture loss (Hassan 2015, Hogan et al.

2012, Zhou et al. 2008a, 2008b) as the bars are sealed

to prevent drying. Such hardening causes consumer

avoidance (McMahon et al. 2009, Hassan 2015).

Particle shape, size, surface composition, and

distribution are influence protein powder functionality in

intermediate moisture foods (Banach et al. 2017,

Huppertz and Hogan 2015, Li et al. 2016).

There are various mechanisms have been proposed

by the researchers for example, aggregation of proteins

following formation of covalent bonds (intermolecular

disulphide bonds) and non-covalent interactions

between the proteins especially whey proteins (Zhou et

al. 2008a, 2008b), Maillard browning reactions between

the carbonyl groups in sugars and amino groups in

proteins that result in protein polymerization leading to

the hardening of products (Tran 2009), moisture

migration between the protein and water/cosolvent

(Hogan et al. 2012, Labuza and Hyman 1998, Li et al.

2008, Liu et al. 1991, Loveday et al. 2009, 2010), phase

separation occurs between the proteins and the sugars

(Loveday et al. 2010, McMahon et al. 2009), changes in

state of water happen at the protein surface and protein

surface-solvent interactions and a function of

hydrophobic interactions between the layers of protein

in HPN bars will tend to aggregate together resulting the

hardness in HPN bars (Ghosh 2018, Hassan 2015). Consumers prefer using natural sugar syrups in

candy bars and foodstuffs instead of alcohol sugar

syrups for some disadvantages and advantages for

example alcohol sugars have some defects in terms of

difficulty digestion and cause bloating and diarrhea

compared to natural sugars. While natural sugar syrups

like agave syrup, brown rice syrup, and honey contain

natural water soluble vitamins and minerals, compare

with alcohol sugars.

The challenge for using natural sugar syrups in

manufacture of such HPN bars may be become hard or

very hard during storage and they had a limited shelf life,

resulting undesirable by consumers because in food,

especially dairy products, texture, not flavor, has

important influence on product acceptance by

consumers because texture perception influences total

sensory evaluation (Hassan 2015, McMahon et al. 2009,

Wilkinson et al. 2000).

Study Objectives

The objectives of present study were to investigate

the quantitative and qualitative effects of whey protein

isolate (WPI), and milk protein concentrate (MPC) or a

mixture of them (WPI + MPC) combined with alcohol

sugar syrups (sorbitol and glycerol) or natural sugar

syrups (agave, rice and honey) or mix from one of them

with glycerol combined with vegetable shortening oil on

the texture and hardness, water activity and color

changes in high-protein nutrition (HPN) bars after

accelerated stored at 35°C for 43 days. This is the first

attempt to study the effect of using natural sugar syrups

(agave, rice and honey) mixed with glycerol and

combined with mixed of WPI and MPC in manufacture

of HPN bars as trying to minimizing bars hardness

during storage in order to meeting consumer demands.

Study was Included Three Phases

Phase 1: manufacture of high protein nutrition (HPN)

bars using only 34% of one protein (WPI or MPC) and

47% of one polyol (Sorbitol or Glycerol), 34% of one

protein WPI or MPC and 47% of two polyols (80:20,

50:50, 20:80 Sorbitol and Glycerol), 34% of two proteins

(80:20, 50:50, 20:80 WPI and MPC) and one polyol

(47% sorbitol), 34% of two proteins (80:20, 50:50, 20:80

WPI and MPC) and 47% of two polyols (80:20, 50:50,

20:80 sorbitol and glycerol). With each bar was used

19% vegetable shortening oil, and stored at 35°C for 43

days in order to know how changes to protein and polyol

affect texture (hardening), water activity and color of

HPN bars (Table 1 and Table 2).

Phase 2: selection the best HPN bar mix at phase 1

gives less hardness after stored at 35°C for 43 days and

using this mix in manufacture of HPN bars with

substitution of sorbitol with three natural sugar syrups

(agave syrup, brown rice syrup, and honey) individually

and stored at 35°C for 43 days in order to learn how

changes to protein and natural sugar syrups influence

texture (hardening), water activity and color of HPN bars

(Table 3).


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Phase 3: depending on best HPN bar mix of quantity

and quality of components in phase 2, we try to using

high levels of proteins (36%, 38%, 40%, and 45%) in

manufacture of HPN bars with alcohol sugar syrups

(sorbitol + glycerol) or natural sugar syrups (agave, rice,

and honey) individually + glycerol, and comparing with

standard of each one, and stored at 35°C for 43 days in

order to learn how changes to protein and polyol or

natural sugar syrups influence on texture (hardening),

water activity and color of HPN bars in order to meeting

consumer demands with HPN bars made with high

protein levels and stay with low hardness during storage

(Table 3).

MATERIALS & METHODS

Bar Ingredients

Whey protein isolate (WPI) Provon 190, 4.5%

moisture, 90% protein was received from Glanbia

Nutritionals (Twin Falls, ID) and milk protein concentrate

(MPC80) 5% moisture, 80% protein was received from

Idaho Milk Products, Inc. (Jerome, ID). Vegetable

shortening (Crisco®) was from The J. M. Smucker Co.

(Orrville, OH) and was manufacture from soybean oil,

partially hydrogenated cottonseed and soybean oils, and

mono and diglycerides, and fully hydrogenated

cottonseed oil,. Sorbitol syrup contains 70% solid

sorbitol and 30% bound water was received from Archer

Daniels Midland Company (Decatur, IL). Glycerol

(99.7%) was received from KIC Chemical Inc. (New

Paltz, NY). Agave syrup (blue agave) contains 70% solid

agave and 30% water, which contains 58% fructose,

20% glucose, and little amount of sucrose was received

from Feysol Nature S.L - Granada-Spain company.

Brown rice syrup contains 80% solid rice and 20% water,

which contains 65% maltose, 10% maltotriose, 5%

dextrins, and 2% glucose was received from Indiamart –

Table 1. Effect of multi-sized (34%) whey protein isolate (WPI2) or milk protein concentrate (MPC3) or mixed of WPI with MPC and 47% alcohol sugars (sorbitol or and glycerol) combined with 19% shortening oil on the water activity (Aw), hardness and relative change in hardness (% RC4) values of high-protein nutrition bars after stored at 35°C for 43 days. (Test of best ingredients% for get less hardening).

Test #

Model bar Composition1

Day 1 Day 43, 35°C

Aw Hardness (g-force)

Aw Hardness (g-force)

%RC

A 34.0%WPI, 47.0%Sorb5 (Standard) 0.635 37.6 0.665 415.2 1004

B 34.0%WPI, 47.0%Glyc6 0.114 17.2 0.132 1200.1 6877

C 34.0%WPI, 47.0% (80%Sorb, 20%Glyc) 0.551 41.4 0.612 276.3 567

D 34.0%WPI, 47.0% (50%Sorb, 50%Glyc) 0.371 52.7 0.425 375.6 613 E 34.0%WPI, 47.0% (20%Sorb, 80%Glyc) 0.180 22.1 0.254 735.7 3229

F 34.0%MPC, 47.0%Sorb 0.670 68.5 0.685 553.0 707 G 34.0%MPC, 47.0%Glyc 0.091 19.4 0.164 1230.1 6241

H 34.0%MPC, 47.0% (80%Sorb, 20%Glyc) 0.564 47.2 0.591 568.4 1104

I 34.0%MPC, 47.0% (50%Sorb, 50%Glyc) 0.381 24.7 0.433 815.8 3203

J 34.0 %MPC, 47.0% (20%Sorb, 80%Glyc) 0.189 20.3 0.290 1021.2 4931

K 34.0%(50%WPI, 50% MPC), 47.0% Sorb 0.650 45.1 0.630 216.6 379

L 34.0% (80%WPI, 20% MPC), 47.0% (80%Sorb, 20%Glyc) 0.543 30.0 0.571 201.5 572

M 34.0% (50%WPI, 50% MPC), 47.0% (80%Sorb, 20%Glyc) 0.546 23.3 0.578 46.0

Softer bar7 97

N 34.0% (20%WPI, 80% MPC), 47.0% (80%Sorb, 20%Glyc) 0.553 34.7 0.590 296.1 753 1All model bar systems contain 19% vegetable shortening oil. 2Whey protein isolate (90% protein, 4.5% moisture). 3Milk protein concentrate (80% protein, 5.0% moisture). 4%RC = [(Hardness – Initial Hardness) / Initial Hardness] x 100. 5Sorbitol syrup (70% solid sorbitol and 30% water). 6Glycerol 99.7%. 7Softer bar has less hardness during storage, its percents of components were used in manufacture of HPN bars in all the following Tables by using sorbitol syrup and natural sugars mixed with 20% glycerol and combined with vegetable shortening oil and using 34%, 36%, 38%, 40%, and 45% protein.

Table 2. Effect of multi-sized (34%) whey protein isolate (WPI2) or milk protein concentrate (MPC3) or mixed of WPI with MPC and 47% alcohol sugars (sorbitol or and glycerol) combined with 19% shortening oil on the color as measured using L*a*b* color system, change in color based on Whiteness Index (WI2) and total color change (ΔE3) of high-protein nutrition bars (as described in Table 1) after stored at 35°C for 43 days.

Test4 #

Day 1 Day 43, 35°C

L a b WI ΔE L a b WI ΔE

A 93.47 -0.54 9.09 88.8 0 76.04 2.50 21.76 67.5 21.6

B 94.87 -0.57 8.59 90.0 0 70.91 -1.61 18.38 65.6 25.9

C 93.37 0.51 8.76 89.0 0 73.59 2.27 20.18 66.7 22.9

D 93.48 -0.69 9.72 88.3 0 72.15 2.85 21.45 64.7 24.6

E 94.44 -0.53 8.89 89.5 0 71.77 2.50 19.63 65.5 25.3

F 92.25 -0.67 11.19 86.4 0 81.33 1.96 21.54 71.4 15.3

G 91.13 -0.99 11.72 85.3 0 73.76 4.33 26.35 62.6 23.4

H 91.74 -0.82 11.54 85.8 0 81.24 2.37 22.14 70.9 15.3

I 92.09 -0.94 11.64 85.9 0 76.84 3.31 23.88 66.6 20.0

J 91.38 -0.96 11.66 85.5 0 74.39 4.32 25.76 63.4 22.7

K 91.37 -0.62 11.25 85.8 0 81.76 1.78 20.99 72.1 13.9

L 90.73 -0.46 9.66 86.6 0 80.85 3.25 26.03 67.5 19.5

M 91.22 -0.63 10.09 86.6 0 78.95 3.27 26.37 66.1 20.8

N 90.74 -0.74 11.26 81.6 0 74.25 2.95 24.10 64.6 21.2 1All model bar systems contain 19% vegetable shortening oil. 2WI= 100- [(100-L*) 2 + (a*) 2 + (b*) 2] ½. 3ΔE = [(a* - a*0)2 + (b* - b*0)2 + (L* - L*0)2]1/2. 4Test # as in Table 1.


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company (India). Honey contains 82.9% solid honey and

17.1% water, which contains 38.2% fructose, 31.3%

glucose, 7.1% maltose, 1.3% sucrose, 17.2% water,

1.5% higher sugars, 0.2% ash, and 3.2% other was

received from Fysol Natur S. L - Granada-Spain

Company.

Manufacture of HPN Bars

Bars were made in small batches (33 gm) of each

formulation that were made in duplicate) by mixing

protein powder, alcohol sugar syrup or natural sugar

syrups, lipid as needed (in Table 1 and Table 3), using

a spatula in small plastic cup until a smooth nougat-like

texture was achieved (≤1.5 min). The mixture of

ingredients was transferred then to plastic sample

containers size 4 cm diameter x 1 cm high; Decagon

Devices, Inc., Pullman, WA), and a tight filling lid placed

on the container and then the container and lid were

sequentially wrapped in parafilm to prevent moisture

loss and aluminum foil to prevent effect of light . Bars

were stored under accelerated storage at 35°C for 43

days. Initial bar hardness for day 1, and hardness after

storage at 35°C for 43 days were measured as well as

water activity and color. All samples were prepared in

duplicate and the average bar water activity; color and

hardness were determined by taking three

measurements on two bars (six measurements /

variable).

Fatty acids of bars ingredients of day 1 and after

storage at 35°C for 43 days were separated (duplicate).

Minerals of bars ingredients of day 1 were estimated

(duplicate).

Water Activity

Water activity testing was carried out using an Aqua

Lab CX-2 meter (Decagon Devices Inc.) standardized at

water activity of 0.760 (using 6.0 molal NaCl) and 0.250

(using13.41 molal LiCl). Samples were measured by

placing enough bar material to cover the full bottom of

the plastic sample cup (Decagon Devices, Inc.) and the

cup integrated into the meter.

Table 3. Percent of ingredients of high-protein nutrition bars made of (34%, 36%, 38%, 40%and 45%) WPI or (50% WPI and 50% MPC) and sorbitol sugar or natural sugars mixed with 20% glycerol combined with shortening oil.

Protein %

Bar #

WPI1 MPC2 Sorbitol Syrup3

Agave Syrup4

Rice Syrup5 Honey6 Glycerol7 Vegetable Shortening

34

1 34 0 47 0 0 0 0 19

2 17 17 37.6 0 0 0 9.4 19

3 34 0 0 47 0 0 0 19

4 17 17 0 37.6 0 0 9.4 19

5 34 0 0 0 47 0 0 19

6 17 17 0 0 37.6 0 9.4 19

7 34 0 0 0 0 47 0 19

8 17 17 0 0 0 37.6 9.4 19

36

1 36 0 45 0 0 0 0 19

2 18 18 36 0 0 0 9 19

3 36 0 0 45 0 0 0 19

4 18 18 0 36 0 0 9 19

5 36 0 0 0 45 0 0 19

6 18 18 0 0 36 0 9 19

7 36 0 0 0 0 45 0 19

8 18 18 0 0 0 36 9 19

38

1 38 0 44 0 0 0 0 18

2 19 19 35.2 0 0 0 8.8 18

3 38 0 0 44 0 0 0 18

4 19 19 0 35.2 0 0 8.8 18

5 38 0 0 0 44 0 0 18

6 19 19 0 0 35.2 0 8.8 18

7 38 0 0 0 0 44 0 18

8 19 19 0 0 0 35.2 8.8 18

40

1 40 0 45 0 0 0 0 15

2 20 20 36 0 0 0 9 15

3 40 0 0 45 0 0 0 15

4 20 20 0 36 0 0 9 15

58 40 0 0 0 45 0 0 15

6 20 20 0 0 36 0 9 15

7 40 0 0 0 0 45 0 15

8 20 20 0 0 0 36 9 15

45

1 45 0 45 0 0 0 0 10

2 22.5 22.5 31.5 0 0 0 13.5 10

3 45 0 0 45 0 0 0 10

4 22.5 22.5 0 31.5 0 0 13.5 10

58 45 0 0 0 45 0 0 10

6 22.5 22.5 0 0 31.5 0 13.5 10

7 45 0 0 0 0 45 0 10

8 22.5 22.5 0 0 0 31.5 13.5 10 1Whey protein isolate (90% protein, 4.5% moisture). 2Milk protein concentrate (80% protein, 1Whey protein isolate (90% protein, 4.5% moisture). 2Milk protein concentrate (80% protein, 5.0% moisture). 3Sorbitol syrup (70% solid sorbitol and 30% water). 4Agave syrup (70% solid agave and 30% water), which contains (58% fructose, 20% glucose, and little amount of sucrose). 5Rice syrup (80% solid rice and 20% water). (65% maltose, 10% maltotriose, 5% dextrins, and 2% glucose). 6Honey (82.9% solid honey and 17.1% water). (38.2% fructose, 31.3% glucose, 7.1% maltose, 1.3% sucrose, 17.2% water, 1.5% higher sugars, 0.2% ash, and 3.2% other. 7Glycerol (99.7%). 8Bar cannot mix.


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Color

Color testing was carried out using a Miniscan XE

Plus portable colorimeter Model 45/O-S (Hunter

Associates Laboratory Inc., Reston, VA) bench-top

colorimeter running with D65 northern daylight light

according to Vissa and Cornforth (2006). Calibration

was using black and white tiles covered with plastic

wrap. Bar and model system samples were separated

from their container and covered in plastic wrap. Color

was expressed in terms of the CIELAB color space with

the coordinates being L* (0-100, estimation of lightness),

a* (red-green) and b* (yellow-blue) (Pagliarini and others

1990). Mean color values were determined from five

measurements taken at different spots on the sample.

Whiteness index (WI) based on Vargas and others

(2008) in which 0 = black and 100 = white as well as

color change during storage (ΔE) based on Banach

(2012).

Texture Analysis (Hardness) Testing

Hardness was measured as maximum load in a

permeation test to 10 mm depth using a TA.XT Plus

texture analyzer (Texture Technologies, Ramona, CA)

with 5-kg load cell and a TA-42 45° chisel knife blade.

Samples were let to reach room temperature (~22°C) for

2 h then tested using a crosshead speed of 1 mm/s and

an activation load of 1 g-force. Three measurements for

hardness were collected on different parts of the sample.

Relative changes in hardness (%RC) were calculated

according to Liu et al. (2009).

Fold minimizing in hardness of bar (F.M) after stored

= Hardness bar of Sugar + WPI after storage / Hardness

bar of Sugar +20% Glycerol + WPI + MPC after storage.

Fatty Acids Testing

Fatty acids of bar ingredients were separated

(duplicate) by GC Technique at Ward Lab

([email protected]), Department of Nutrition, Dietetic,

and Food Sciences at Utah State University, Logan,

USA.

Minerals Testing

Minerals of bar ingredients were estimated

(duplicate) using the atomic absorption absorber Atomic

Bulk Spectrophotometer Bulk at USU Analytical Labs

([email protected]) at Utah State University, Logan, USA.

RESULTS & DISCUSSION

Visual Observations during Bars Manufacture

and Storage

Depending on visual, observation and feel of the bars

by tactile hand, in general all bars of alcohol sugar

syrups and natural sugar syrups were initially soft,

malleable and white to cream in color but brown

coloration was observed after stored at 35°C for 43 days

and differences were observed in the hardness and

color during manufacture and storage of bars depending

on the quantity and quality of ingredients were used in

bars and storage conditions (Table 1 and Table 3).

After manufacture and during accelerated storage of

high protein nutrition (HPN) bar there were none-

equilibrium interaction systems among water, protein,

and polyols, and from areas of high to low water activity

(Aw) due to the hydration behavior of individual

components and the competition for available moisture.

At the first time the migration of water takes place from

the higher Aw polyol syrups to the lower Aw protein

powders, and then the migration of water occur from the

protein powders to polyol syrup with the magnitude and

speed of migration influencing the degree and rate of bar

hardening. During day one observations were bar A (standard

bar) made from WPI, sorbitol syrup and vegetable

shortening oil was soft malleable dough with nougat-like

consistency. Bar B of WPI and glycerol and bar G of

MPC and glycerol were the softer bars. Bar F made from

MPC and sorbitol had a more crumbly texture and harder

than bar A. Bars C, D, H, and K were harder, while the

other bars were softer than bar A. Bars B, C, and E were

whiter than bar A, while the other bars were less

whiteness (Table 2). Other observations at day 1 of bar of brown rice

syrup at 34%, 36%, and 38% protein were initially harder

than agave syrup and honey bars and brown rice syrup

had difficult in mixing and packing it in cups, so at 40%

and 45% of protein content we could not mixing its

contents because brown rice syrup has gummy texture

and contains 80% solid matters and 20% water (Table

5).

Table 4. Effect of multi-sized (34%, 36%, 38%, 40% and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on the water activity (Aw) of high-protein nutrition bars (as described in Table 3) after stored at 35°C for 43 days.

Protein %

Bar 1 2 3 4 5 6 7 8

Sorbitol syrup WPI

Sorb+Glyc WPI+MPC

Agave syrup WPI

Agave+Glyc WPI+MPC

Rice syrup WPI

Rice+Glyc WPI+MPC

Honey WPI

Honey+Glyc WPI+MPC

d 1 d 43 d 1 d 43 d 1 d 43 d 1 d 43 d 1 d 43 d 1 d 43 d 1 d 43 d 1 d 43

34 0.652 0.680 0.549 0.581 0.556 0.654 0.503 0.572 0.487 0.538 0.473 0.530 0.481 0.580 0.452 0.550

36 0.635 0.679 0.550 0.593 0.558 0.648 0.488 0.572 0.485 0.517 0.460 0.562 0.468 0.580 0.448 0.548

38 0.630 0.678 0.549 0.590 0.540 0.650 0.484 0.576 0.450 0.506 0.445 0.558 0.467 0.573 0.441 0.551

40 0.628 0.676 0.545 0.589 0.535 0.646 0.488 0.573 -2 - 0.460 0.566 0.458 0.575 0.439 0.553

45 0.615 0.668 0.582 0.615 0.521 0.641 0.548 0.609 - - 0.527 0.607 0.450 0.569 0.520 0.600 1All the information below the Table is described in Table 3. 2Bar cannot mix.

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920

Visual observations after stored at 35°C for 43 days

all bars had changes in hardness and color, and

consistency depending on quantity and quality of

ingredients was used in bars and storage conditions

(Table 1 and Table 3). Sugar alcohols bars of 34%

protein, bar of glycerol with MPC (Bar G) or with WPI

(Bar B) and bar of 20% sorbitol and 80% glycerol with

MPC (Bar J) were the harder bars, while the softer bar

was bar M of 50:50 WPI and MPC with 80% sorbitol and

20% glycerol (Table 1 and Fig. 1).

Hardness of standard bars of alcohol sugar syrup

(sorbitol syrup) or natural sugars syrups (agave or rice

or honey) mixed with 34%, 36%, 38%, 40% and 45% of

WPI after stored at 35°C for 43 days were as the

following: honey > agave > rice> sorbitol (note: at 40%

and 45% protein, bar of rice cannot mix), while hardness

of multi-sized bars of alcohol sugar syrup (80% sorbitol

sugar syrup) or (80% agave or rice or honey) mixed with

20% glycerol and mixed WPI and MPC after stored at

35°C for 43 days were as the following: rice > agave >

honey > sorbitol (Table 5).

In general, during storage the hardness of standard

bars of natural sugar syrups were very hard and they

has rigid and crunchy texture with bad flavor (except

honey in flavor) after storage and undesirable for

consumes at protein concentrations above 34%

(especially at 38%, 40% and 45% protein), while by

using two proteins (WPI and MPC) mixing with glycerol

Table 5. Effect of multi-sized (34%, 36%, 38%, 40%and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on hardness (g-force), relative change in hardness (RC%2) and fold minimizing in hardness of bar (F.M3) of HPN bars (as described in Table 3) after stored at 35°C for 43 days.

Protein %

System

Bar 1 2 3 4 5 6 7 8

Sorbitol syrup WPI

Sorb+Glyc WPI+MPC

Agave syrup WPI

Agave+Glyc WPI+MPC

Rice syrup WPI

Rice+Glyc WPI+MPC

Honey WPI

Honey+Glyc WPI+MPC


34

Hardness 36 427 17 41 26 1629 16 302 266 1008 51 831 49 2092 20 363

RC% 1086 141 6070 1788 279 1529 4169 1715

F.M 10.4 5.4 1.2 5.8

36

Hardness 43 623 19 80 34 2113 19 527 323 1100 62 983 84 2575 26 567

RC% 1349 321 6115 2674 241 1485 2965 2081

F.M 7.8 4.0 1.1 4.5

38

Hardness 64 985 26 198 62 3012 23 985 629 1244 79 1189 120 4446 39 886

RC% 1439 662 4758 4183 98 1405 3605 2172

F.M 5.0 3.1 1.1 5.0

40

Hardness 96 1177 40 251 123 3655 31 1138 -4 - 222 2151 185 4945 70 991

RC% 1126 528 2872 3571 - - 869 2573 1316

F.M 4.7 3.2 - 5.0

45

Hardness 232 2092 41 355 250 6025 68 1290 - - 241 2359 471 6447 80 1100

RC% 802 766 2310 1797 - - 879 1269 1275

F.M 5.9 4.7 - 5.9 1All the information below the Table is described in Table 3. 2RC% = [(Hardness – Initial Hardness) / Initial Hardness] x 100.

3F.M= Hardness bar of Sugar + WPI of d 43 / Hardness bar of Sugar +20% Glycerol + WPI + MPC of d 43. 4Bar cannot mix.

Fig. 1. Effect of multi-sized (34%) whey protein isolate (WPI2) or milk protein concentrate (MPC3) or mixed of WPI with MPC and 47% alcohol sugars (sorbitol or and glycerol) combined with 19% shortening oil on the hardness (g-force) of high- protein nutrition bars (as described in Table 1) after stored at 35°C for 43 days. (Test of best ingredients% for get less hardening).


921

and natural sugar syrups we decreased all bars

hardness more and made them desirable in consume at

all protein levels with desirable flavor, except brown rice

bar stayed hard and has crunchy texture, and

undesirable for consumes especially at 45% protein. Brown color in all bars of standard natural sugar

syrups of all protein levels after stored at 35 for 43 days

were as the following: agave > honey > sorbitol > rice

(note: standard rice bars of 40% and 45% cannot mix

since there is less water in bars for the proteins to be

fully hydrated), while brown color by using two proteins

mixing with glycerol and natural sugar syrups were as

the following: honey > agave > rice > sorbitol (Table 6

and Table 7).

Water Activity

In general, water activity (Aw) values of all high-

protein nutrition (HPN) bars of proteins and alcohol

sugar syrups or natural sugar syrups depend on

ingredients that were used (quantity and quality of

proteins, sugars and lipids) and conditions of storage of

HPN bars. HPN bars water activity of alcohol sugars of 34%

WPI or MPC with 47% glycerol only (Bar B and G) or

with 20% sorbitol and 80% glycerol (Bar E and J), or

with 50% sorbitol and 50% glycerol (Bar D and I) were

very low to low (0.114, 0.091, 0.180, 0.189, 0.371 and

0.381) respectively at day 1, since in these bars, 50%,

80% and 100% of the sorbitol syrup was substituted with

glycerol and the only moisture was that in WPI and MPC,

while Aw was increased to 0.132, 0.164, 0.254, 0.290,

0.425 and 0.433 respectively after stored at 35°C for 43

days (Table 1). HPN bars of glycerol was the most

effective polyol in lowering water activity and provided

the soft texture of HPN bars during the first day of

Table 6. Effect of multi-sized (34%, 36%, 38%, 40% and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on the color as measured using L*a*b* color system, change in color based on Whiteness Index (WI2) and total color change (ΔE3) of high-protein nutrition bars (as described in Table 3) after stored at 35°C for 43 days.

Protein %

Color systems

Bar 1 2 3 4 5 6 7 8

Sorbitol syrup WPI

Sorb+Glyc WPI+MPC

Agave syrup WPI

Agave+Glyc WPI+MPC

Rice syrup WPI

Rice+Glyc WPI+MPC

Honey WPI

Honey+Glyc WPI+MPC


34

L 91.69 77.33 89.87 82.42 90.83 48.52 89.67 60.43 89.55 85.17 89.15 64.87 90.36 58.37 88.82 58.85

a 0.08 2.43 -0.42 2.47 0.81 14.27 -0.12 12.96 0.15 2.55 -0.33 11.40 0.55 13.01 0.17 12.59

b 10.73 24.29 11.20 25.45 15.56 26.70 14.30 36.03 14.32 24.25 13.30 34.63 14.29 31.25 14.19 36.42

WI 86 67 85 69 82 40 82 40 82 71 83 49 83 46 82 44

ΔE 0 20 0 16 0 46 0 40 0 11 0 35 0 38 0 39

36

L 92.20 75.34 89.92 81.76 89.12 48.85 91.20 60.27 88.06 86.21 90.21 65.33 90.00 59.41 89.56 59.86

a 0.10 2.32 -0.38 2.66 0.58 13.79 0.13 12.52 0.14 1.69 -0.23 10.93 0.62 11.94 0.24 12.31

b 11.34 23.24 12.03 26.03 13.96 25.18 14.42 32.45 14.00 21.71 13.68 30.87 13.81 32.53 13.98 33.47

WI 86 66 84 68 82 41 83 45 82 74 83 52 83 47 83 46

ΔE 0 21 0 16 0 44 0 38 0 8 0 32 0 38 0 40

38

L 93.04 73.91 89.70 81.05 91.19 49.46 90.53 55.21 90.22 87.51 90.02 66.22 90.79 62.53 88.81 58.48

a 0.02 2.97 -0.44 3.66 0.77 13.68 -0.06 13.16 0.26 1.00 -0.26 20.38 0.55 11.46 0.18 12.86

b 11.17 25.88 11.98 28.05 15.09 23.94 14.21 34.39 14.02 19.26 13.32 28.93 14.22 28.71 14.54 34.51

WI 87 63 84 66 83 42 83 42 83 77 83 51 83 52 82 45

ΔE 0 24 0 19 0 45 0 43 0 6 0 35 0 34 0 38

40

L 92.48 72.73 88.92 79.60 91.72 49.98 89.50 56.70 -4 - 90.96 65.82 91.10 62.91 89.57 58.81

a 0.24 3.02 -0.27 3.75 0.78 14.38 0.19 13.39 - - -0.11 1140 0.63 11.79 0.23 12.79

b 11.40 24.50 12.71 28.67 15.06 26.69 15.10 35.77 - - 13.46 33.31 14.25 30.54 14.27 34.95

WI 86 63 83 65 83 42 82 42 - - 84 51 83 51 82 44

ΔE 0 24 0 19 0 45 0 41 - - 0 34 0 34 0 39

45

L 91.97 75.83 87.95 76.93 91.78 53.90 88.14 56.38 - - 88.50 60.25 91.16 68.03 87.76 55.39

a 0.28 2.95 -0.26 4.86 0.86 13.50 0.08 13.35 - - 0.06 12.86 0.61 10.71 0.25 13.59

b 11.87 26.30 13.77 31.66 14.15 24.78 15.86 34.69 - - 14.27 33.91 14.00 29.38 15.15 35.11

WI 86 64 82 60 84 46 80 39 - - 82 46 83 55 81 42

ΔE 0 22 0 22 0 41 0 39 - - 0 37 0 30 0 40 1All the information below the Table is described in Table 3. 2WI= 100- [(100-L*) 2 + (a*) 2 + (b*) 2] ½. 3ΔE = [(a* - a*0)2 + (b* - b*0)2 + (L* - L*0)2]1/2. 4Bar cannot mix.

Table 7. Effect of multi-sized (34%, 36%, 38%, 40% and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on the color average as measured using L*a*b* color system, change in color based on Whiteness Index (WI2) and total color change (ΔE3) of high-protein nutrition bars (as described in Table 3)

Protein %

(Average)

Color Systems (Average)

Bar 1 2 3 4 5 6 7 8

Sorbitol syrup WPI

Sorb+Glyc WPI+MPC

Agave syrup WPI

Agave+Glyc WPI+MPC

Rice syrup WPI

Rice+Glyc WPI+MPC

Honey WPI

Honey+Glyc WPI+MPC


45- 34

L 92.28 75.03 89.27 80.35 90.93 50.14 89.81 57.80 89.28 86.30 89.77 64.50 90.68 62.25 88.90 58.28

a 0.14 2.74 0.35- 3.48 0.92 13.92 0.15 13.08 0.18 1.75 0.17- 13.39 0.59 11.78 0.21 12.83

b 11.30 24.84 12.34 12.75 14.76 25.46 14.78 34.67 14.11 21.74 13.61 32.33 14.11 30.48 14.43 34.89

WI 86 65 84 66 83 42 82 42 82 74 83 50 83 50 82 44

ΔE 0 22 0 14 0 44 0 40 0 8 0 35 0 35 0 39 1All the information below the Table is described in Table 3. 2WI= 100- [(100-L*) 2 + (a*) 2 + (b*) 2] ½. 3ΔE = [(a* - a*0)2 + (b* - b*0)2 + (L* - L*0)2]1/2. 4Bar cannot mix.


922

manufacture, this result agree with Liu and others 2009,

Hassan 2015. Water activity values of other HPN bars were

between 0.543 of bar L: 34% (80% WPI, 20% MPC),

47% (80% Sorbitol, 20% Glycerol ) and 0.670 of bar F:

34% MPC and 47% Sorbitol at day 1 and it was

increased to 0.571 and 0.685 respectively after stored at

35°C for 43 days. bar F Aw value > bar L since bar F has

MPC and sorbitol only and the MPC powder contained

slightly more moisture than WPI, in addition to replaced

20% of sorbitol with glycerol in bar L (Table 1). Use of

certain alcohol sugars such as glycerol or sorbitol in

made of HPN bars change the rate-water activity profile;

glycerol decreased water activity as compared to

sorbitol appears to act as an preventive at all aw values,

probably due to glycerol had low viscosity and since the

only moisture was that in the protein. Water activity of HPN bars of sorbitol syrup and

natural sugar syrups bars at all levels of proteins were

used (34%, 36%, 38%, 40% and 45% of WPI and MPC)

at day 1 and after stored at 35°C for 43 days was

decreased with increase of protein levels because

replaced some of protein with sorbitol syrup and natural

sugar syrups decreased water content in bars of 47% to

45%, 44%, 45% and 45% sorbitol respectively (Table 4).

Comparing between standard of HPN bars of sorbitol

syrup and natural sugar syrups when 20% of sorbitol

was replaced with 20% glycerol in bars, produced

decreased Aw content since glycerol was free from

moisture, while substituted 50% of WPI with 50% MPC

causes slightly increase in bars water content because

5.0% water in MPC and 4.5% water in WPI, but this has

slightly effect on Aw compare with when use 20%

glycerol instead of 20% sorbitol (Table 4).

Water activity of all bars was slightly increased after

stored at 35°C for 43 days (Table 1 and Table 4)

because the brown color increased since Maillard

browning reaction releases free water molecules in

addition to during storage some intermediate water was

changed to free water and bound water (Hassan 2015,

Li et al. 2008). Any loss of intermediate water

(plasticizer water around the protein particles) to bulk

and bound water would cause in a loss of ability of

solvent molecules to preserve protein flexibility.

Bar Color

In general, color values as measured using L* a* b*

color system, change in color based on whiteness Index

(WI) and total color change (ΔE) of all HPN bars of

alcohol sugar syrups or natural sugar syrups depend on

ingredients were used in bars manufacture (quantity and

quality of proteins, sugars), water content and conditions

of storage of HPN bars (Table 1, Table 2, Table 3,

Table 6 and Table 7). All bars of alcohol sugar syrups

and natural sugar syrups were initially soft, malleable

and white to cream in color but brown coloration was

observed after stored at 35°C for 43 days and

differences were observed in the hardness and color

during manufacture and storage of bars.

In general there was loss in whiteness (an increase

in coloration) measured as whiteness index (WI) values

of HPN bars (A - N) after storage from between 81.6 –

90.0 to 62.6 – 72.1. The WI of bars B, C, and E at day 1

were whiter than standard bar A of only WPI and sorbitol,

and the other bars were less, while after stored at 35°C

for 43 days WI value of bar L = A, and bars F, H, and K

were whiter and all the other bars had less WI than bar

A. Also, WI value of bar F (MPC and sorbitol) > bar of A

(WPI and sorbitol > of bar B (WPI and glycerol) and

equal to 71.4, 67.5, and 65.6 respectively after stored at

35°C for 43 days (Table 1 and Table 2). There was loss in bars whiteness after stored at 35°C

for 43 days as glycerol was added into the bar

formulation of WPI or MPC and this gradual increased

as more glycerol was added, i.e., the total color change

(∆E) value was higher and bars of WPI had more

affected and higher than of MPC for example bars of

WPI (bar B = 25.9 > E= 25.3 > D= 24.6 > C = 22.9) while

bars of MPC (bar G = 23.4 > J = 22.7 > I = 20.0 > H =

15.3) compare with WPI standard bar A = 21.6 and MPC

bar F = 15.3 (Table 1 and Table 2).

The loss in bars whiteness after stored at 35°C for 43

days was more gradual increased as 20% glycerol with

increased the amount of MPC were added into the WPI

with sorbitol bars formulation for example the ∆E value

= 21.2 of bar N of (20 WPI : 80 MPC combined with 80

sorbitol : 20 glycerol) > 20.8 of bar M of (50 WPI : 50

MPC combined with 80 sorbitol : 20 glycerol) > 19.5 of

bar L of (80 WPI : 20 MPC combined with 80 sorbitol :

20 glycerol) > 13.9 of bar K of (50 WPI : 50 MPC

combined with sorbitol only) (Table 1 and Table 2).

The differences in HPN bars browning after storage

related to some possible factors effect on browning

reactions. Factor one is percent of protein in WPI and

MPC and their lactose content since that MPC (80%

protein) contains more reducing sugar lactose than WPI,

while WPI contains more protein (90%) than MPC, this

means high amino acids in WPI. Increasing the lactose

content results increases the rate of browning, so having

less browning in MPC bars (e.g., bar F has ∆E= 15.3)

rather than WPI bars (e.g., bar A has ∆E= 21.6) is related

to the proteins and not the lactose content (Table 2). It

suggests there are more available amino groups in WPI

bars than MPC bars. Factor two is glycerol percents are

used in bars since glycerol has lower viscosity cause

increase mobility of the Maillard browning reactants so

that lactose can react with amino groups on the surface

of the proteins and increase browning color of HPN bars

during storage. Factor 3 is water content and Factor 4 is

storage conditions (time and temperature).

The differences in color values of HPN bars of sugar

syrups of sorbitol, agave, rice, and honey depending on

their differences in quantity and quality of proteins and


923

sugars and water contents in syrups as mentioned in

Table 3.

In general, HPN bars of alcohol sugar syrups and

natural sugar syrups were initially has white to cream

color especially standard bar 1 of sorbitol, while there

were an increase in coloration measured as whiteness

index (WI) mean values of HPN bars (1 - 8) at day 1

compare with after stored at 35°C for 43 days as the

following: (from between 87 - 86 to 67 – 63 of standard

bar 1 of sorbitol, 85 - 82 to 69 – 60 of bar 2) and (from

between 84 – 82 to 46 – 40 of standard bar 3 of agave;

83 – 80 to 45 – 39 of bar 4) and (from between 83 – 82

to 77 – 71 of standard bar 5 of rice, 84 – 82 to 52 – 46

of bar 6) and (from 83 to 55 – 46 of standard bar 7 of

honey; 83– 81 to 46 – 42 of bar 8) (Table 6 and Fig. 6).

Total color change (∆E) mean values of HPN bars (1

- 8) after stored at 35°C for 43 days as the following:

(from between 20 - 24 of standard bar 1 of sorbitol, 16 -

22 of bar 2) and (from between 41 - 46 of standard bar

3 of agave,39 - 43 of bar 4) and (from between 6 - 11 of

standard bar 5 of rice, 32 - 37 of bar 6) and (from

between 30 - 38 of standard bar 7 of honey and 38 - 40

of bar 8) (Table 6 and Fig. 7).

Fig. 2. Effect of multi-sized (34%, 36%, 38%, 40%and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on hardness (g-force) of HPN bars (as described in Table 3) after stored at 35°C for 43 days.

Fig. 3. Effect of multi-sized (34%, 36%, 38%, 40%and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on relative change in hardness (RC%) of HPN bars (as described in Table 3) after stored at 35°C for 43 days.


924

An increase in coloration of mean values of L*, a*,

b* standard bars of 34 - 45% WPI with sorbitol, or agave,

or rice, or honey at day 1 and after stored at 35°C for 43

days of standard bar 1 of sorbitol with L* (lightness)

values of 93.04 - 91.69 to 77.33 – 72.73, a* values of

0.28 - 0.02 to 3.02 – 2.32 and b* values of 11.87 - 10.73

to 26.30 – 23.24; standard bar 3 of agave with L* values

of 91.78 – 89.12 to 53.90 – 48.52, a* values of 0.86 –

0.58 and b* values of 15.56 – 13.96, standard bar 5 of

rice with L* values of 90.22 – 88.06 to 87.51 – 85.17, a*

values of 0.26 – 0.14 to 2.55 – 1.0 and b* values of 14.32

– 14.00 to 24.25 – 19.26, standard bar 7 of honey with

L* values of 91.16 – 90.00 to 68.03 – 58.37, a* values of

0.63 – 0.55 to 13.01 – 10.71 and b* values of 14.29-

13.81 to 32.55 – 28.71 (Table 6).

An increase in coloration mean values of L*, a*, b*

of bars of 34 – 45% proteins of 50 WPI:50 MPC with 20%

syrups of sorbitol, agave, rice and honey substitution

with glycerol at day 1 and after stored at 35°C for 43

days of bar 2 with L* values of 89.92 – 87.95 to 82.42 -

76.93, a* values of -0.26 - (- 0.44) to 4.86 - 2.47 and b*

values of 13.77 – 11.20 to 31.66 - 25.45, bar 4 with L*

values of 91.20 – 88.14 to 60.43 - 55.21, a* values of

0.19 - (-0.12) to13.39 - 12.52 and b* values of 15.86 –

14.21 to 36.03 - 32.45, bar 6 with L* values of 90.96 –

88.50 to 66.22 - 60.25, a* values of 0.06 - (-0.33) to

Fig. 4. Effect of multi-sized (34%, 36%, 38%, 40%and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on fold minimizing in hardness of bar (F.M) of HPN bars (as described in Table 3) after stored at 35°C for 43 days.

Fig. 5. Glycerol- protein complex: left- docking of glycerol, right- hydrogen bonds, hydrophobic interactions, and dipole-dipole interactions (Van der Walls forces) bonding to protein surface. The same thing can happen with sorbitol, poly, di and monosaccharide, and its polyol derivatives. Also, can happen with secondary products of lipid peroxidation (a mixture of aldehydes , epoxides, ketones, and other products obtained from the products obtained from the decomposition of lipid hydroperoxides) .

H

HO- C-H

H-C-OH

H -C-OH

H

Arg R-group

ggggggroup

group NH2 HN

HN+

H

H

HO- C-H

H-C-O

H

H -C-O - H

H

O

C

¨¨¨¨

Protein

surface

¨..

¨

¨

¨

Hydrophobic pocket

Glycerol Glycerol

Protein

surface

Hy

dro

ph

ob

ic

Inte

ract

ion

s

H.bonds

ss

OH

HH

H CH3

CH3

Van der Walls forces

Peptide bond

N

3

c=o.….H H.b

Carbonyl group for other peptide chain

Ser,Thr,Tyr R-groups

Aliphatic AAs R-groups

NH2

¨¨¨¨

Lys R-group

S

S

Cys-Cys disulfide bond

- O

C

O

Asp&Glu

R-groups

Ionic bond

S S

S S

H2O

O

S S

H2O

O

S S


925

20.38 - 10.93 and b* values of 14.27 – 13.30 to 34.63 -

28.93, bar 8 with L* values of 89.57 - 87.76 to 59.86 -

55.39, a* values of 0.25 – 0.17 to 13.59 - 12.31 and b*

values of 15.15 - 13.98 to 36.42 - 33.47 (Table 6).

Depending on results of change in color values

above based on L* a* b* color system, whiteness Index

(WI) and total color change (ΔE) of all HPN bars of

alcohol sugar syrups or natural sugar syrups after

storage, all bars lost whiteness with decreases in L* and

increases in a* and b* values (Table 6, Table 7, Fig. 6,

Fig. 7 and Fig. 8). Brown color in all bars of standard

natural sugar syrups of all protein levels after stored at

35 for 43 days were as the following: agave > honey >

sorbitol > rice (note: standard rice bars of 40% and 45%

cannot mix), while brown color of bars using of 34 – 45%

proteins of 50 WPI:50 with 20% syrups of sorbitol,

agave, rice and honey substituted with glycerol were as

the following: honey > agave > rice > sorbitol (Table 6,

Table 7, Fig. 6, Fig. 7 and Fig. 8).

Bar Hardening

In general, hardness (g-force) and relative change in

hardness (RC%) and fold minimizing in hardness of bar

Fig. 6. Effect of multi-sized (34%, 36%, 38%, 40% and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on the color as measured using change in color based on Whiteness Index (WI) of high-protein nutrition bars (as described in Table 3) after stored at 35°C for 43 days.

Fig. 7. Effect of multi-sized (34%, 36%, 38%, 40% and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on the color as measured using change in color based on the total color change (ΔE) of high-protein nutrition bars (as described in Table 3) after stored at 35°C for 43 days.


926

(F.M) values of all high-protein nutrition (HPN) bars of

alcohol sugar syrups or natural sugar syrups depend on

ingredients were used in bars manufacture (quantity and

quality of proteins, sugars and lipids) and conditions of

storage of HPN bars (Table 1, Table 3, Table 5, Fig. 1,

Fig. 2 and Fig. 4).

Hardness of HPN bars of sugar alcohols of 34% WPI

or MPC with only 47%% glycerol (Bar B and G) or with

20% sorbitol and 80% glycerol (Bar E and J), or with

50% sorbitol and 50% glycerol (Bar D and I) were very

low (except Bar D is low) (17.2, 19.4, 22.1, 20.3, 52.7

and 24.7) respectively at day 1, while hardness values

were increased to 1200.1,1230.1, 735.7, 1021.2, 375.6

and 815.8 respectively after stored at 35°C for 43 days

(Table 1 and Fig. 1).

Hardness values of other HPN bars (except of Bar

M) at day 1 were between 30.0 and 68.5 g-force of Bar

L= 34% (80% WPI, 20% MPC), 47% (80% Sorbitol, 20%

Glycerol ) and of Bar F= (34% MPC and 47% Sorbitol)

respectively, and increased to 201.5 and 553.0

respectively, while the softer bar M {34% (50% WPI,

50% MPC), 47% (80% Sorbitol, 20% Glycerol)}

hardness 23.3 at day 1 and 46.0 g-force after stored at

35°C for 43 days. Using higher contents of MPC, such

as 20 WPI: 80 MPC or 100% MPC combined with 80%

sorbitol and 20% glycerol has a negative impact since

the MPC becomes the main protein making up the bar

matrix and this increase bar hardness to 296.1 (bar N)

and 568.4 g-force (bar H) after stored at 35°C for 43

days compare with 46.0 of bar M and 415.2 of standard

bar A and bars made using 100% MPC has brittle and

crumbly texture (Table 1).

Hardness progression of HPN bars of alcohol sugar

syrups after stored at 35°C for 43 days were as the

following: Bar G (harder bar) > B > J > I > E > H > F > A

standard bar) > D > N > C > K > L > M (softer bar) (Table

1 and Fig. 1). From these results appear that using MPC with

glycerol caused bars at day 1 to be very soft and brittle,

but too hard and too crumbly and unpalatable compared

with using MPC and sorbitol or standard bar of WPI and

sorbitol after stored at 35°C for 43 days since there is no

water in a mixture, while bar of MPC and sorbitol softer

but brittle and a lack of cohesiveness and a crumbly and

become unpalatable compare with standard bar of WPI

and sorbitol.

Since MPC contains 81.3% protein (about 60%

casein and 20% whey protein), whereas WPI contains

about 91.2% protein, so the presence of whey proteins

appears to plasticize the bar matrix, also WPI was

almost completely dissolved protein because WPI are

more hydrophilic properties than MPC, which are larger

particle size and more hydrophobic because they

contain more casein protein the solvent and cosolvent

have hydrophilic properties so, MPC are less soluble in

solvent and cosolvent and a very large number of

undissolved powder particles was found within the

protein matrix of the bars then the MPC particles has

large size and not have continuous proteinaceous phase

like WPI when bars were examined using Confocal laser

scanning microscopy (CLSM) (Hassan 2015, Huppertz

and Hogan 2015, Li et al. 2016) found protein powder

functionality in semi-solid intermediate moisture foods

influence by particle size, surface composition,

distribution, and particle shape. Banach and others

Fig. 8. Effect of multi-sized (34%, 36%, 38%, 40% and 45%) WPI or (50% WPI + 50% MPC) and sorbitol sugar or natural sugars (agave, rice, honey) mixed with 20% glycerol combined with shortening oil on the color as measured using change in color based on average of L*, a*, b* of high-protein nutrition bars (as described in Table 3) after stored at 35°C for 43 days.


927

(2017) found reduction particles size and shape of MPC

improved its plasticizing capability in bars and produced

bars with better properties (less crumbly, more textural

stability, better cohesiveness and expand sensory shelf

life).

Using WPI and sorbitol syrup as alone sugar in

manufacture of HPN bar, initially the dough was soft,

malleable, and easily formed into bars and had the best

consistency and remained flexible after stored at 35°C

for 43 days, and since particles size of sorbitol molecule

size larger than water molecule and most of bar

ingredients of protein-solvent/cosolvent interactions

would be with water molecules there would be

preferential exclusion of sorbitol molecules from near the

protein surface.

Using WPI and glycerol as alone sugar, at day 1

inhibited the rate of bar hardening caused bars initially

very soft, malleable since glycerol has a lower viscosity,

and it is using as a plasticizing factor in HPN bars, but

bar rapidly hardens to very high levels after stored at

35°C for 43 days because the non-covalent interactions

(hydrogen bonds and van der Waals and ionic forces)

with the surface of protein molecules of protein layers

would be with the hydroxyl groups of glycerol and

glycerol has less possible interactions with other glycerol

molecules compared with water and so there is a greater

entropic effect with relation to hydrophobic moieties of

the protein and leading to a firmer texture (Fig. 5).

Glycerol act as a better plasticizer than sorbitol since

has lower glass transition temperature than sorbitol (Liu

and other 2009), and glycerol is less excluded from the

protein surface (Chanasattru et al. 2008) since it has low

molecular weight. Also, McClements (2001) reported

that glycerol works less favorably with protein

hydrophobic regions than water since in the presence of

a nonpolar group water can still rearrange and form

hydrogen bonds with other water molecules. In contrast,

such rearrangement of glycerol requires that the

hydrogen bonds between its alcohol groups be broken.

Alcohol sugars, sorbitol and glycerol are initially

acting as plasticizers as a lubricant to facilitate the

movements of the protein layer over each other and a

plasticizer disrupts the protein –protein polymer

interactions and a long time these polyols especially

glycerol could lose plasticizing ability and have greater

interactions with the proteins in the HPN bar (Fig. 5),

possibly do increase hydrophobic interactions of the

protein molecules and cause to a harder texture

(Hassan 2015). During storage, bars with glycerol more

harder than bars manufacture with sorbitol since this

may be has relationship to how glycerol interacts with

the surfaces of protein molecules that then increase

aggregation and leading to a firmer bars.

Glycerol interacts with the protein in different ways of

mechanisms depending on its quantity of combination

with sorbitol syrup since it can either increase or

decrease hardening in HPN bars made using WPI or

MPC during storage depending on the amount of

glycerol added in bar manufacture. If added glycerol

more than sorbitol then hardening was increased and if

glycerol less than sorbitol then hardening was

decreased.

Using 80% of the glycerol with 20% sorbitol syrup in

bars of WPI and MPC at day 1 decrease the rate of bar

hardening caused bars initially soft, malleable and softer

than 100% glycerol but harder than standard bar of WPI

after stored at 35°C for 43 days, while, using 50:50 of

sorbitol syrup and glycerol in WPI and MPC bars was

softer than substitution of 80% sorbitol. The smaller

glycerol molecules are preferentially included in the local

domain around the protein surface along with water

molecules.

Using two proteins combined with one sugar or using

one protein combined with two sugars in HPN bars have

similar effects on the HPN bars but, the magnitude of

those effects is distinctly different, since the effect of two

proteins were considerably larger than the effect of two

sugars on bar hardening and the effect of using two

proteins or two alcohol sugars on the HPN bars was

more than one protein or one sugars. Using two proteins combined with two alcohol sugars

were reduced HPN bar hardness more than two proteins

combined with one sugar or two sugars combined with

one protein, while using 50:50 WPI and MPC combined

with 80% sorbitol and 20% glycerol in manufacture of

HPN bars (bar M) gave the softest HPN bar (fold

minimizing in hardness of bar = 9.0) compare with

standard bar A of WPI and sorbitol only since the

particulate protein powder particles of MPC interrupt the

formation of an extensive protein network structure of

WPI (Hassan 2015, Santhoshkumar et 2015). Furthermore, adding a lower portion of glycerol

(20%) with sorbitol syrup (80%) give solvent-cosolvent

mixture contains different sizes of ingredients and

glycerol is present always with water and a larger

cosolvents of sorbitol syrup or nature sugar syrups

(agave, rice and honey) and this inhibits bar hardening

by masking and shielding hydrophobic regions on

protein surfaces by glycerol and decreased the entropic

effects of hydrophobic groups in relation to water since

glycerol molecules are oriented with their hydrocarbon

backbone laying parallel to the hydrophobic moieties of

the protein. In this case, it is possible for glycerol to

positively interact with the protein hydrophobic moieties

through its three-carbon backbone. At the same time,

glycerol hydroxyl groups expand away from the protein

surface and are available for hydrogen bonding with

surrounding sorbitol cosolvent molecules subsequently

the proteins remain in a relatively non-aggregated form

and bar hardening is decreased (Hassan 2015).

At the same time this ways of mechanisms achieved

when glycerol used at a lower level than natural sugar

syrups (agave, rice and honey) that used instead of

sorbitol syrup and this caused retards bar hardening of


928

these sugars (Table 1, Table 3, Table 5, Fig. 1, Fig. 2

and Fig. 4).

With increases of protein levels of WPI or MPC uses

in manufacture of HPN bars the bars hardness will

increase, but when use a mixture of so% WPI and 50%

MPC combined with a mixture of 80% sorbitol and 20%

glycerol in bars manufacture the hardness will inhibited

during bars storage and this lets manufacture of HPN

bars contain higher protein levels. Depending on some of surprised results of high-

protein nutrition bars in Table 1 and Fig. 1 especially of

bar M as a softer HPN bar {34% (50% WPI, 50% MPC),

47% (80% Sorbitol, 20% Glycerol)} had 23.3 at day 1

and 46.0 g- force (RC% 97) after stored at 35°C for 43

days (fold minimizing (F.M) in hardness of bar M = 9.0)

compared with standard bar A (34% WPI, 47% sorbitol

and 19% shortening oil (its hardness 37.6 at day1 and

415.2 g- force with RC% 1004) after stored at 35°C for

43 days (Table 1 and Fig. 1), so we chosen ingredients

of HPN bar M in manufacture of all the following HPN

bars of sorbitol syrup with or without 20% glycerol and

natural sugar syrups (agave syrup, rice syrup, and

honey) with or without 20% glycerol and this lets HPN

bars to be manufacture and contain higher protein levels

than 34%, such as 36%, 38%, 40% and 45% protein

(Table 3). Hardness of HPN bars of sorbitol syrup with or

without 20% glycerol (standard bars) and natural sugar

syrups with or without 20% glycerol (standard bars) at all

protein percents (34%, 36%, 38%, 40%, and 45% of

50% WPI + 50% MPC) were increased at day 1 and after

stored at 35°C for 43 days depending on increase in

protein percents since substitution of 2% to 3% of

sorbitol syrup and natural sugar syrups cosolvent

(plasticizer) with protein percents in bars (Table 5 and

Fig. 2) since decrease percents of sugars and polyols

minimize plasticizing effect on hardness of HPN bars in

addition to the water percent in these sugars. Also,

higher protein content in HPN bars might increase the

firmness of the product, which could result in rubbery

mouth-feel and undesirable texture and hardening

during storage. Comparing influence sorbitol syrup and natural sugar

syrups (agave, rice, and honey) of all protein percents

(34%, 36%, 38%, 40% and 45%) of 50:50 WPI and MPC

with 80% sorbitol + 20% glycerol versus WPI + sorbitol

syrup or with 80% agave syrup + 20% glycerol versus

WPI + agave syrup or with 80% rice syrup + 20%

glycerol versus WPI + sorbitol or with 80% honey + 20%

glycerol versus WPI + honey on HPN bars hardness

after stored at 35°C for 43 days caused minimize of bar

hardness and caused fold minimizing (F.M) in hardness

of bar as the following: 10.4, 5.4, 1.2 and 5.8 fold of 34%

protein, 7.8, 4.0, 1.1 and 4.5 fold of 36% protein, 5.0, 3.1,

1.1 and 5.0 fold of 38% protein, 4.7, 3.2, - and 5.0 fold

of 40% protein, and 5.9, 4.7, - and 5.9 fold of 45% protein

respectively (note: standard rice bars of 40% and 45%

cannot mix since there is deficient water in HPN bars for

the proteins to be completely hydrated) (Table 5 and

Fig. 4).

Hardness of standard HPN bars of sugar syrups of

sorbitol, agave, rice, and honey were as the following:

Honey > Agave > Rice > Sorbitol while, hardness of bars

of a mixture of 50% WPI and 50% MPC with 20%

glycerol combined with 80% sorbitol, agave, rice, or

honey as the following: Rice > Agave > Honey > Sorbitol

(Table 5 and Fig. 2) because there is differences in

quantity and quality of alcohol sugars and natural sugars

ingredients in HPN bars and its ability work as plasticizer

since sugars and polyols themselves can function as

weakly interacting cosolvents (McClements 2002) in

addition to the water in these sugars and have a

stabilizing agent on protein structure (Crowe et al. 1987). In general, mixing bar ingredients such as bar 2

(Sor + Glyc) and 45% (WPI + MPC) decreased hardness

from 2092 g-force of standard bar 1 of (sorbitol and 45%

WPI ) to 355 g-force and this interesting value less than

427 g-force of standard bar 1 of (sorbitol and 34%WPI),

While hardness of HPN bar of 38% protein of bar 4

(Agave + Glyc) and bar 8 (Honey + Glyc) equal to

hardness of standard bar 1 (sorbitol and 38% WPI) =

985 g-force, while hardness of bar 8 (Honey + Glyc) was

less than them and equal to 886 g-force (Table 5).

Relative change in hardness (RC%) of standard

sugars bars after stored at 35°C for 43 days were agave

bar 3 > honey bar 7 > sorbitol bar 1 > rice bar 5 at all

protein percents of 34%, 36%, 38%, 40% and 45%

protein (note: standard rice bars of 40% and 45% cannot

mix), while RC% of HPN bars of mix of 50:50 WPI and

MPC with 20% glycerol combined with 80% sorbitol,

agave, rice, or were as the following: agave bar 4 >

honey bar 8 > rice bar 6 > sorbitol bar 2 after stored at

35°C for 43 days (Table 5 and Fig. 3). Results of hardening and water activity explained

there was relationship between increases rate of

hardening and water activity values after stored of HPN

bars at 35°C for 43 days and these results agree with

Hassan (2015) when he found a significantly increases

in hardening and water activity caused a significantly

decrease in the amount of water (intermediate water <

0.1% of total water) able of influential as a plasticizer in

HPN bars and caused significantly increase in the

amount of free and bound waters and this is agree with

Li and others (2008), but these results were not the

reason of bars hardening.

In general, hardness of the HPN bars can be

attributed to a various number of mechanisms during

storage have been proposed by the researchers for

example, aggregation of proteins following formation of

covalent intermolecular disulphide bonds and non-

covalent interactions between the proteins especially

whey proteins, Maillard browning reactions between the

carbonyl groups in sugars and amino groups in proteins

that result in protein polymerization, moisture migration


929

between constituents of the protein and water/cosolvent,

phase separation occurs between the proteins and the

sugars (Zhou et al. 2008a, Loveday et al. 2009,

McMahon et al. 2009, Zhou et al. 2013). Also, Hardening

of HPN bars by protein aggregation seems to be related

to changes in state of water happen at the protein

surface and protein surface-solvent interactions and a

function of hydrophobic interactions between the layers

of protein in HPN bars will tend to aggregate together

resulting the hardness in HPN bars (Hassan 2015). In

addition, we can add that hardening of bars is related to

protein surface-solvent interactions by non-covalent

interactions (hydrogen bonds and van der Waals and

ionic forces not by disulphide bonds)) with the protein

layers would be with the hydroxyl groups of glycerol (Fig.

5).

From the interesting results above and other results

in Table 1, Table 5, Fig. 1, Fig. 2 and Fig. 4 we can

recommended that using a mixture of 50 WPI:50 MPC,

and 80% sorbitol syrup or natural sugar syrups (agave,

rice and honey) combined with 20% glycerol in HPN bars

formulations in order to improve its cohesiveness and

textural stability, and minimizing hardening of bars to

expand sensory shelf life of such dairy products for

consumer, in addition to meeting consumer demands

with high protein levels.

Bar Fatty Acids

HPN bar is including ≥10% fat (Zhu and Labuza

2010, Hassan 2015). A fat is added to supply flexibility

of the HPN bars, which is including vegetable shortening

oil (McMahon et al. 2009, Adams 2008, Hassan 2015),

canola and soy oils (Adams 2008), cocoa butter

(Loveday et al. 2009, 2010, Hassan 2015), and basically

any class of food category oil (Gautam et al. 2006). The compositional profiles of common plant oils such

as vegetable shortening oils are predominated by

palmitic (16:0), stearic (18:0), oleic (18:1), linoleic (18:2),

and linolenic (18:3) fatty acids. In general, there were no

clear differences between bars in percents of fatty acids,

but after stored at 35°C for 43 days, there were slightly

decrease in unsaturated fatty acids {trans-Vaccenic acid

(C18:1n7), cis-oleic acid (C18:1n9), cis-linoleic acid

(C18:2n6) and α-Linolenic acid (C18:3n3)} of HPN bars

(1 – 8) facing to slightly increase in saturated fatty acids

{palmitic acid (C16:0) and stearic acid (C18:0)}, while

there is nearly no effect on myristic acid (C:14) and

arachidic acid (C20:0) (Table 8 and Fig. 9).

The percent values of fatty acids of all bars were

C18:2n6 > C18:1n9 > C16:0 > C18:0 > C18:3n3 >

C18:1n7 > C20:0 > C14:0 with mean values at day 1 and

after stored at 35°C for 43 days of C18:2n6 values 0.24

– 0.26 to 0.25 – 0.26 and C18:1n9 values 19.02 – 19.57

to 18.85 – 19.51 and C16:0 values 16.15 – 16.91 to

16.12 – 17.04 and C18:0 values 10.57 – 11.99 to 10.99

– 12.28 and C18:3n3 values 5.59 – 5.76 to 5.56 – 5.77

and C18:1n7 values 1.50 – 1.59 to 1.48 – 1.53 and

C20:0 values 0.32 – 0.33 to 0.33 – 0.34 and C14:0

values 0.24 – 0.26 to 0.25 – 0.26 (Table 8 and Fig. 9). There was not study found about effect of storage on

fatty acids of vegetable shortening oil using in

manufacture of HPN bars of alcohol sugar syrups

(sorbitol and glycerol) and natural sugar syrups (agave,

rice, and honey), so this considered the first study about

that.

Table 8. Fatty acids percents of high-protein nutrition bars made of 34% WPI or (50% WPI + 50% MPC) and 80% sorbitol sugar or natural sugars (agave, rice and honey) mixed with 20% glycerol and combined with 19% vegetable shortening oil at day 1 and after stored at 35°C for 43 days.

Test #

Bar Composition8

10Fatty Acids%

Day 1 Day 43, 35°C

C14:0 C16:0 C18:0 C18:1 n7

C18:1 n9

C18:2 n6

C18:3 n3 C20:0 C14:0 C16:0 C18:0 C18:1

n7 C18:1

n9 C18:2

n6 C18:3

n3 C20:0

1 34.0%WPI1, 47.0%Sorb3. (Standard)

0.24 16.25 10.75 1.58 19.48 45.55 5.69 0.32 0.25 16.76 11.93 1.48 19.17 44.31 5.61 0.34

2 17.0%WPI, 17.0% MPC2, 37.6%Sorb.

9.4%Glyc7.

0.24 16.21 10.72 1.59 19.46 45.62 5.70 0.32 0.26 17.02 12.14 1.52 18.94 44.08 5.56 0.34

3 34.0%WPI, 47.0%

Agave4 (Standard)

0.25 16.15 10.57 1.55 19.57 45.68 5.76 0.32 0.25 16.82 11.91 1.51 19.06 44.38 5.6 0.33

4 17.0%WPI, 17.0%

MPC, 37.6%Agave, 9.4%Glyc.

0.24 16.18 10.74 1.55 19.5 45.58 5.74 0.32 0.26 17.04 12.28 1.50 18.85 44.03 5.57 0.34

5 34.0% WPI, 47.0% Rice5

. (Standard) 0.24 16.18 11.06 1.50 19.55 45.28 5.72 0.33 0.25 17.01 11.98 1.53 18.91 44.24 5.60 0.33

6 17.0%WPI, 17.0% MPC, 37.6% Rice,

9.4%Glyc. 0.24 16.26 10.92 1.56 19.43 45.40 5.72 0.32 0.25 16.12 10.99 1.51 19.51 45.38 5.77 0.33

7 34.0%WPI, 47.0% Honey6 (Standard) 0.25 16.46 11.43 1.52 19.28 44.91 5.67 0.33 0.25 16.52 11.53 1.50 19.31 44.73 5.68 0.34

8 17.0%WPI, 17.0%MPC,

37.6%Honey, 9.4%Glyc.

0.26 16.91 11.99 1.51 19.02 44.23 5.59 0.33 0.26 16.94 12.08 1.52 18.98 44.19 5.56 0.33

8All model bar systems contain 19% vegetable shortening oil. 9All the information below the Table is described in Table 3. 10 Myristic acid (C14:0), Palmitic acid (C16:0), Stearic acid (C18:0), trans-Vaccenic acid (C18:1n7), cis-Oleic acid (C18:1n9), cis-Linoleic acid (C18:2n6) and α-Linolenic acid (C18:3n3) and Arachidic acid (C20:0).


930

Bar Minerals

The compositional profiles of milk protein (WPI) with

sorbitol syrup and natural sugar syrups (agave , rice, and

honey) combined with vegetable shortening oil are

dominated by eight minerals, Fe= Iron, Na= Sodium, Si=

Silica, Zn= Zinc, Ca= Calcium, K= Potassium, Mg=

Magnesium and P= Phosphorus. Honey bar dominated

by six of them (Fe, Zn, Ca, K, Mg and P) with values of

7.06 and 2.65 mg/kg, 5.95, 50.13, 1.92 and 3.88 %

respectively, while bar of sorbitol dominated by Al, B, Mo

and Si with values of 0.62, 0.29, 0.33 and 39.2 mg/kg

respectively, and rice bar dominated by Na= 839 mg/kg

(Table 9 and Fig. 10). There was not study found about determination of

minerals content in HPN bars of alcohol sugar syrups

(sorbitol and glycerol) and natural sugar syrups (agave,

rice, and honey), so this considered the first study about

that.

CONCLUSION

1. Hardening of HPN bars was related to protein

surface-solvent interactions by non-covalent

interactions (hydrogen bonds and van der Waals and

ionic forces not by disulphide bonds or browning

reactions or water activity) with the protein layers would

be with the hydroxyl groups of sugars especially of

glycerol and its functioning of hydrophobic interactions

between the hydrophobic layers of protein in HPN bars

will tend to aggregate together resulting the hardness in

HPN bars. 2. Effect of using a mixture of two proteins (WPI and

MPC) or two alcohol sugars (sorbitol and glycerol) in

made of HPN bars has more effect on inhibition of bars

hardness than one protein or on sugars, while the effect

of using two proteins combined with two alcohol sugars

on the HPN bars was more effect than two proteins

combined with one sugar or two sugars combined with

on protein, while using of 34% - 45% milk proteins of

(50% WPI and 50% MPC) combined with 80% (sorbitol

Fig. 9. Effect storage of high protein nutrition bars on fatty acids percents of vegetable shortening oil at day 1 compared with after stored at 35°C for 43 days.

Table 9. Minerals content of high-protein nutrition bars made of 34% WPI and 47% sorbitol sugar or natural sugars (agave or rice or honey) combined with 19% vegetable shortening oil at day 1.

Standard Bar Composition8

Minerals Content10

mg/kg %

Al As B Ba Cd Co Cr Cu Fe Mn Mo Na Ni Pb Se Si Sr Zn Ca K Mg P S

34.0%WPI1, 47.0%Sorb3.

0.62 <11 0.29 0.60 < < 0.19 < 3.04 < 0.33 774 < < < 39.2 1.99 0.33 0.20 0.14 0.04 0.10 0.42

34.0%WPI, 47.0%Agave4 0.51 < 0.17 0.56 < < 0.12 < 3.63 < 0.22 775 < < < 28.7 1.86 1.23 1.17 4.06 1.01 1.08 0.41

34.0% WPI, 47.0% Rice5

0.26 < 0.15 0.57 < < 0.15 < 2.51 < 0.26 839 < < < 27.7 1.85 0.15 0.19 0.13 0.04 0.10 0.41

34.0% WPI, 47.0% Honey6 0.33 < 0.22 0.55 < < 0.17 < 7.06 < 0.29 801 < < < 34.5 1.97 2.65 5.95 50.13 1.92 3.88 0.40

8All model bar systems contain 19% vegetable shortening oil. 9All the information below the Table is described in Table 3. 10Al= Aluminum, As= Arsenic, B= Boron, Ba= Barium, Cd= Cadmium, Co= Cobalt, Cr= Chromium, Cu= Copper, Fe= Iron, Mn= Manganese, Mo=Molybdenum, Na= Sodium, Ni= Nickel, Pb= Lead, Se= Selenium, Si= Silica, Sr= Strontium, Zn= Zinc, Ca= Calcium, K= Potassium, Mg= Magnesium, P= Phosphorus, S= Sulfur. 11<

= Mineral contents is low.


931

or agave or rice or honey) and 20% glycerol in

manufacture of HPN bars gave the softer HPN bars. 3. Glycerol interacts with the protein in different

mechanisms depending on its quantity of combination

with sorbitol syrup and we can say with natural sugar

syrups (agave, rice and honey) since it can either

increase or decrease hardening in HPN bars made

using WPI or MPC during storage depending on the

amount of glycerol added in bar manufacture. If added

glycerol more than sorbitol or natural sugar then

hardening was increased and if glycerol less than

sorbitol or natural sugars then hardening was

decreased. 4. Hardness of standard (WPI) HPN bars of sugar

syrups of sorbitol, agave, rice, and honey were as the

following: Honey > Agave > Rice > Sorbitol while,

hardness of HPN bars of a mixture of 50% WPI and 50%

MPC with 20% glycerol combined with 80 sorbitol,

agave, rice, or honey as the following: Rice > Agave >

Honey > Sorbitol.

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