Narendra Modi

Drawbacks of traditional fluid

preservation techniques

• Microbial spoilage

• Loss of heat sensitive nutrients and vitamins

• Fruit juice suspension

• Enzymatic discoloration

• Prolonged processing time 15 – 45 min.

• Added with additives and preservatives.

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Division of Food science & Post Harvest Technology

Introduction

• Sonication is alternative technology to

replace conventional heat treatment

process.

• More energy efficient

• Less processing time

• Environment friendly

Sonication

Defined as inaudible sound waves at a frequency above 20 KHz.

Sound waves having

frequency more than 20

kHz are known as

ultrasounds /

Ultrasonication /

Sonication

(Dujmic et al., 2013)

Thermo-sonication – combination tretment of ultrasound and mild heat ( 50 °c – 60 ° c )

Manosonication - Combination with increase in pressure (< 600 Mpa)

(Lee et al., 2004)

Ultrasonic systems employed for fluid food processing

Experimental Setup

(1) ultrasound transducer (2) ultrasonic generator(3) ultrasound probe (19 mm)(4) data logger(5) temperature probe(6) Jacketed beaker(7) computer(8) water inlet(9) water outlet(h) depth of probe in thesample (25 mm).

Mechanism of Ultrasonication

1. Cavitation or Microbubbles

formation

2. Lethal effect on

Microorganisms

Cavitation

Lethal effect on Microorganisms

Intracellular cavitation, thus enhancing the permeability and thinning of cell membranes (Soria & Villamiel, 2010).

control Heat Treatment at 40 °C for 3 min Sonication at 40 °C for 3 min

A)

Effect of US processing on physicochemical

properties of some fluid foods.

S.N Food Matrix

US treatments Major findings References

1 Mangojuice

40 kHz/130 W/15–60min/25 °C

Significant increase in carotenoids(4–9%), TPC (30–35%) for US-treated samples (15 and 30 min),compared to control.

Santhirasegaram et al.,(2013)

2 Guavajuice

35 kHz/20 °C/30 min Significant increase in Ascorbicacid (8%) compared to controlsamples.

Cheng et al.,(2007)

4 Apple juice 25 kHz/amplitude 70 μm/20 °C/60 min

Total plate count Yeast and molds 1.2 & 1.3 log reduction respectivly

Abid et al. (2014)

Case studies

Ultrasonics Sonochemistry 21 (2014) 93-97

Muhammad abid et al.,

Objectives

• To evaluate the effects of sonication treatments onthe selected polyphenolic compounds, sugars, totalcarotenoids, total anthocyanins, essential minerals,viscosity and electrical conductivity of apple juice.

Materials and methods

• Fresh apple fruits (M. domestica cv. Fuji)• Electrical juice extractor

Treatment • 0 min ( fresh untreated apple juice)- control • 30 min• 60 min • Temp 20 °c• Frequency – 20 Khz and amplitude – 70 %

Effect of sonication treatement on polyphenolic compounds of apple juice (mg/L)

Polyphenolic compound

Control US treatment (30 min)

US treatment (60 min )

Chlorogenic acid 61.27 ± 0.07 C 85.82 ± 0.04 a 85. 55 ± 0.09 b

Caffeic acid 3.08 ± 0.06 b 3.66 ± 0.09 a 3.66 ± 0.07 a

Catechin 14.69 ± 0.04 c 17.58 ± 0.07 a 17.15 ± 0.06 b

Epicatechin 13.49 ± 0.09 c 33.05 ± 0.12 a 31.27 ± 0.08 b

Phloridzin 1.88 ± 0.07 b 3.31 ± 0.06 a 3.32 ± 0.05 aIncreased conc due to disruption of cells leads liberation of Phenols & attachment of OH molecules to the aromatic phenol rings

Effect of sonication treatments on sucrose, glucose and fructose of apple juice (g/L)

Ultrasound treatment breaks the cells which leads to diffusion of sugars from intracellular spaces into liquid

Effect of sonication on total carotenoids, total anthocyanins,viscosity and electrical conductivity of apple juice

Mechanical Disruption of cell walls may enhance the carotenoids in the juice & increased viscosity is due to disruption of macromolecules creates colloidal solution which makes increase in viscosity

0

2

4

6

8

10

12

14

16

Totalcarotenoids

(µg/mL)

TotalAnthocyanin

(mg/L)

Viscosity (cP) EC (ms/cm)

Control US 30 US60

Effect of sonication treatment on mineral elements of apple juice (mg/L)

Inference

1. Significant increase in phenolic compounds and sugars occurs when juice is sonicated for 30 min.

2. Total carotenoid , mineral element & viscosity increased significantly at 60 min.

3. There is no effect of sonication on improving the total anthocyanin, Zn & electrical conductivity.

Adekunte A.O et al., 2010 Food Chemistry 122: 500–507

Objective To investigate the efficacy of sonication for yeastinactivation in tomato juice and to model changes inselected quality and nutritional parameters as a function ofamplitude level and treatment time.

Materials and methods

• Fresh tomatoes• stored at 3 ± 1 °c

Treatment • Samples - 80 ml• Frequency 20 kHz• Amplitude 24.4–61 µm• Time 2–10 min

Effect of sonication on the quality parameters of tomato juice at a treatment time of 10 min.

Inference

• No significant differences in pH, Brix or TA were observed in sonicated samples.

• Sonication has a significant effect on juice colour, ascorbic acid content and yeast inactivation.

• A 5 log reduction was achieved in 7.5 min at an amplitude of 61 µm.

AIM: Combining ultrasound and UV light techniquesInvestigating the effect on quality attributes and compare theresults with conventional thermal processing.

Treatment conditions: 5 log microbial reduction for all processedjuices.

Objective:To obtain a processed food without any offensive odor and colordevelopment during storage and Retaining all important bio-components in the food

A study into the optimization of ultrasound based processing forachieving the desired log reduction as per the FDA guidelines hasalso been presented.

Material

Filtered juice ofFruits - oranges and sweet lime vegetables - carrots and spinach Stored at 4o C

Treatments

• Pasteurization: 80oC/ 10 min• Ulrasonication: 20kHz/ 15 min (<30oC), 100 W • UV: alone could not give 5 log reduction uptil 30 min (not

covered)• UV+ US: 100 W/ 15 min + UV lamps 8W (2 nos.)

• Scale up:Ultrasonic reactor (5L); Power: 150W, 36 kHz; UV lamps 8W (2 nos.)

Ascorbic acid

TOTAL PHENOLICS

Max content observed only in US treatment

Antioxidant activity (DPPH)

Other studies

• Sugars anslysis

• Scale up (5L)

Microbial growth (preliminary)

• pH played a decisive role (prod. of OH- radicals)

• Untreated : inc. upto 109 cfu/mL

• Thermally pasterurized: no growth

• UV+US: significantly slow growth

Inference • Microbial content: no significant difference

b/w thermal and no-thermal t3

• Excellent nutritional quality can be attainedwith use of US compared to thermal t3

• US juices were a par with fresh juice

• Considering taste, goodness and health, US isthe best option for fruit juice processing.

Future trust

• Optimization by changing time, frequency, temperature for individual fruits and vegetable juices

• Understanding the effect of US on enzymes, juice yield and microbial growth retardation

• Studies on combined use of US with other treatments

Muhammad Aadil et al., 2013

Effect of ultrasound on pH, TSS (Brix), EC, acidity, colour values & non-enzymatic browning of grapefruit juice.

Objective

Material

• Fresh grapefruits• Domestic juice extractor

Treatments

• Control (0 min)• Time 30, 60 and 90 min.• Frequency - 28 kHz• Temperature – 20o C

Effect of sonication on Brix, pH, titratable acidity, cloud value in grapefruit juice (n = 3).

Effect of sonication on EC, colour and non enzymatic browning in grapefruit juice (n = 3).

Effect of sonication on ascorbic acid, total phenols, flavonoids in grapefruit juice (n = 3).

Effect of sonication on flavonols in grapefruit juice (n =3).

Inference

• No significant differences in pH, acidity and Brix level.

• Significant increases in EC were observed after ultrasound treatments.

• Small differences in colour were also observed but overall quality of grapefruit juice was improved.