Post on 23-Dec-2015
Food BiotechnologyDr. Kamal E. M. Elkahlout
Food Biochemistry 5 Vitamins and minerals
Vitamins Micronutrients
Minor components but essential constituents in foods absence in diet affect the health of people absorption levels affects its bioavailability
which also affects cell function and thus health
CategoriesFat-solubleDissolve in fatCan be stored
Water-solubleDissolve in waterCarried in bloodstream, not stored
A, D, E, K C and B-complex vitamins
A and D excess can be harmfulE and K usually not
Excess amounts may cause extra work on kidneys
Thiamin (B1) Functions:
Helps produce energy from carbs
Sources: Whole-grain and
enriched grain products
Beef Liver
Thiamine (B1)Deficiency
Decrease in activity of enzymes. Beriberi (neurological and cardiac
symptoms (severe) sources: legumes seeds, pericarp and germ of cereals, yeast, vegemite, milk and whole grain bread
Loss in cooking water, due to heat, change in pH,
metal ions and ionic strength. Also destroyed by sulfites .(added to fruits &
veg to prevent browning)
Riboflavin (B2) Functions:
Produce energy Changes tryptophan
(amino acid) into niacin
Sources: Liver Yogurt and milk Enriched grains Eggs Green, leafy veggies
Riboflavin
Deficiencylead to accumulation of amino acids so
there is decrease of glutathione reductase activity in red cells
Stability Unstable when exposed to uv light
Niacin Functions:
Helps body use sugars/fatty acids
Helps enzymes function normally
Produces energy
Sources: Foods high in protein
typically (poultry, fish, beef, peanut butter, legumes)
Enriched and fortified grains
Nicotinamide (Niacin)
Deficiency Serious is pellagra (affects skin, digestion and
nervous system – dermatitis, diarrhea and dementia)
Stability quite stable in heat and processAvailability increases slightly during baking due to
alkaline conditions (baking powder)Loss occurs in cooking water due to leaching.
Pyridoxine (B6) Functions:
Helps body make non-essential amino acids
Helps turn tryptophan into niacin and serotonin
Help produce body chemicals (insulin, hemoglobin, etc)
Sources: Chicken Fish Pork Liver Whole grains Nuts Legumes
Pyridoxine (B6)
Deficiency Results in protein metabolic disorders eg
haemoglobin synthesis
Loss during cooking in cooking water extensive loss in dried milk due to interaction
with sulfhydryl groups of proteins
Vitamin B12 (cobalamin) Functions:
Works with folate to make RBC’s
In many body chemicals and cells
Helps body use fatty acids/amino acids
Sources: Animal products Meat Fish Poultry Eggs Milk, other dairy
Cobalamin, B12
Stability
Quite stable to food processing and cooking at pH4-6
However,destroyed in alkaline media or in the presence of reducing agents E.g. Ascorbic acid and SO2
Folate (folic acid) Functions:
Produces DNA and RNA, making new body cells
Works with vitamin B12 to form hemoglobin
May protect against heart disease
Lowers risk of neural tube defects in babies
Controls plasma homocystine levels (related to heart disease)
Sources: Fortified and enriched
grains and breakfast cereals
Orange juice Legumes Green, leafy veggies Peanuts Avacados
Folic acid (Folacin, B9 )
Deficiency leads to anaemia
Loss vitamin C helps preserve folic acid in food, loss
in milk due to oxidative process. However, no destruction during blanching of vegetables.
Biotin Functions:
Produces energy Helps body use
proteins, carbs, and fats from foods
Helps maintain steady blood sugar level,helps strengthen hair and nails
Sources: Wide variety of foods Eggs Liver Wheat germ Peanuts Cottage cheese Whole grain bread
Biotin
Deficiency rare except in people who eat large
amounts of raw egg (cooking releases biotin from protein)
Stable vitamin-loss occurs during processing and storage.
Pantothenic Acid Helps produce
energy Helps the body use
proteins, fat, and carbs from food
Sources: Found in almost all
foods Meat, poultry, fish Whole grain cereals Legumes Milk Fruits, veggies
Pantothenic acid, B5
Deficiency is rare
Loss 10% during milk processing also during
cooking of vegetables due to leaching
Vitamin C Functions:
Helps produce collagen (connective tissue in bones, muscles, etc)
Keeps capillary walls, blood vessels firm
Helps body absorb iron and folate
Healthy gums
Heals cuts and wounds
Protects from infection, boosts immunity
Antioxidant Sources
Citrus fruits Other fruits, veggies
Ascorbic acid (C)
Deficiency leads to scurvy-failure of wounds to heal
Stability Very unstable-readily oxidised to
dehydroascorbic acid and then oxidized to2, 3-diketogulonic acid which has no biological function.
Alkaline pH increases loss, high temperatures increases loss.
Fat Soluble Vitamins
Stored in the fatty tissues-eg liver
Accumulated Soluble in fat-need fat to be absorbed
in body and can lead to toxicityNot required daily
Vitamin A (and carotenoids) Functions:
Normal vision Protects from
infections Regulates immune
system Antioxidant
(carotenoids) Carrotinoids Used in
food industry as a colorant (orange) (label friendly)
Food sources: Liver Fish oil Eggs Fortified milk or other
foods Red, yellow, orange,
and dark green veggies (carotenoids)
Vitamin ALoss
High temperatures and oxygen affect stability. quite stable in food processing and storage
Vitamin D (the sunshine vitamin) Functions:
Promotes absorption of calcium and phosphorus
Responsible for calcium deposition in bone matrix
Regulates cell growth Plays role in immunity
Sources: Sunlight (10 – 15 mins
2x a week) Salmon with bones Milk Orange juice
(fortified) Fortified cereals
Calciferol, cholecalciferol (vitamin D)
Deficiency- impaired bone formation-increased
secretion of Ca and P leading to osteomalacia (weakening and softening)
Excessive intake hypercalcaemia-calcium deposition in
various organs.
Loss Sensitive to oxygen and light
Vitamin E Functions:
Antioxidant, may lower risk for heart disease and stroke, some types of cancers
Protects fatty acids and vitamin A
Sources: Vegetable oils Foods made from oil
(salad dressing, margarine)
Nuts Seeds Wheat germ Green, leafy veggies
α –tocopherol, (vitamin E)
Stablity Quite stable except for autoxidation. loss in activity in commercial deep fried
frozen foods
Vitamin K Functions:
Helps blood clot Helps body make
some other proteins
Sources: Body can produce on
its own (from bacteria in intestines)
Green, leafy veggies Some fruits, other
veggies, and nuts
Vitamin K
Deficiency- reduced acitivity of prothrombin-leads to
hemorrhage
Loss Destroyed by light and alkali Stable to atmospheric oxygen and heat
What Are Minerals? Regulate body processes Give structure to things in the body No calories (energy) Cannot be destroyed by heat constituents which remain as ash after
incineration of plant and animal tissues
Categories of minerals Major minerals
Calcium Phosphorus Magnesium Electrolytes (sodium,
chloride, potassium)
Trace minerals Chromium Copper Flouride Iodine Iron Manganese Selenium Zinc
Sodium
Maintains osmotic pressure of extracellular fluid
Present mostly as an extracellular constituents
Activates enzymes such as amalyse Excess intake-hypertension Food sources-salt,meat,milk Deficiency-various disorders Requirement-300-350mg
Potassium, K
Regulates osmotic pressure within cells, involved in cell membrane transport
Sources-major sources are potatoes and molasses, white bread is potassium deficient
Magnesium (mg)
Roles: Constituents and activator of many
enzymes including Conversion of energy-rich phosphate
compounds Stabilizer of plasma, intracellular
membranes and nucleic acids Life-supporting element Requirement-300-350mg Deficiency-various disorders
Calcium Ca essential nutrient:
abundant in skeleton and other tissues building and maintenance of bones blood clotting and muscle contraction
Requirement is 0.8-1.0g
Major sources are milk and other dairy products, however low in fruits and vegetables, cereals, meat, fish and eggs
Chloride, Cl
Role It serves as a counter ion for Na in
extracellular fluid and for hydrogen ions in gastric juice
Its absorption is rapid as its excretion in urine
Food sources-salt-NaCl
Phosphate, P
Has a role in metabolism
Calcium :phosphate ratio should be 1 in food
Trace elements Iron, Fe Present in haemoglobin and myoglobin pigments
Present in other enzymes as peroxidase, catalase, hydroxylases and flavine
Deficiency causes anemia Iron from vegetable sources –poorly absorbed-
called non haem iron Iron from animal sources-haem iron well absorbed Vitamin C increases absorption Phytates in bran impairs absorption.
Problems on fortification of food with iron
Higher chance of oxidation in wheat flour and decreased baking ability
Catalyses oxidation of fat or oil, increased turbidity of wine and supports growth of iron –requiring bacteria
Copper, Cu
Component of a no. of oxidoreductase (SOD, tyrosinase, urinase, amine oxidase
Bound to ceruloplasmin in plasma (catalyses oxidn of Fe2+ to Fe3+- form transported by transferrin protein to Fe pool in liver
Catalyses oxidative destruction of ascorbic acid
Zinc, Zn
Component of certain enzymes such as
alcohol dehydrogenase, lactate dehydrogenase, malate dehydrogenase, etc
Zn poisoning due to food kept in Zn-plated metal containers
Manganese (Mn)
Metal activator for pyruvate carboxylase
Activates enzymes as arginase, amino peptidase, alkaline phosphatase, etc
Relatively non-toxic
Cobalt, Co
Component of vitamin B 12
Chromium, Cr
Helps in the utilisation of glucose Activates phosphoglucomutase Increase activity of insulin deficiency cause
decrease glucose tolerance Increase risk of CVD
Selenium, Se
Is an antioxidant Enhance tocopherol activity Component of glutathione peroxidase Protect membranes from oxidative
destruction
Fluorine
Required for growth and reproduction
Inhibits tooth decay by retarding solubilization of tooth enamel and inhibiting enzyme involved in dental caries
Iodine, I Utilised in thyroid gland in biosynthesis of
hormone thyroxine Deficiency results in goiter (enlargement of
thyroid gland)
Good sources are seafoods
Fortification-Iodization of common salt (100μg to 1-10g NaCl – combat the deficiency
Higher amounts are toxic – affect reproduction and lactation in animals