Food BiotechnologyDr. Tarek Elbashiti

Food Biochemistry 4 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 carbohydrates and amino acids (Coenzyme)

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, 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 (cofactor)

Changes tryptophan (amino acid) into niacin

Sources: Liver Yogurt and milk Enriched grains Eggs Green, leafy

veggies

Riboflavin (B2)

Deficiency Lead to accumulation of amino acids

so there is decrease of glutathione reductase activity in red cells

Stomatitis including painful red tongue with sore throat, chapped and fissured lips (cheilosis), and inflammation of the corners of the mouth

Stability Unstable when exposed to UV light

Niacin (B3)

Functions: Precursor of

NAD&NADP 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 processingAvailability increases slightly during baking due to

alkaline conditions (baking powder)Loss occurs in cooking water due to leaching.

Pyridoxine (B6) Functions: Cofactor in many

enzyme reactions in amino acid, glucose, and lipid metabolism. 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) B9, M, Bc 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 Avocados

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 (B7, H, coenzyme R) 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).

Found to develop dermatitis and neuromuscular dysfunction.

Stable vitamin-loss occurs during processing and storage.

Pantothenic Acid (B5)

Synthesize coenzyme-A (CoA)

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 Avocados Broccoli

Pantothenic acid, B5

Deficiency is rare

Loss 10% during milk processing also during

cooking of vegetables due to leaching

Vitamin C Functions: Cofactor in at least

eight enzymatic reactions, including several collagen synthesis reactions 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 to 2,3-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 Need fat to be absorbed in body and can lead to toxicity

Not required daily

Vitamin A (and carotenoids)

Functions: Normal vision Protects from

infections Regulates immune

system Antioxidant

(carotenoids) Carotenoids 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 A

Loss

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)

Stability Quite stable except for autoxidation. Loss in activity in commercial deep fried

frozen foodsDeficiency RBCs destruction Impaired of immune response Myopathies Peripheral neuropathy

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 activity of prothrombin-leads to

haemorrhage

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 amylase 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 (ferroxidase) in plasma (catalyses oxidation 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 utilization of glucose Activates phosphoglucomutase Increase activity of insulin deficiency cause

decrease glucose tolerance Increase risk of CVD (cardiovascular

disease)

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 sea foods

Fortification-Iodization of common salt (100μg to 1-10g NaCl – combat the deficiency

Higher amounts are toxic – affect reproduction and lactation in animals