Food Biotechnology
Dr. 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
Categories
Fat-soluble
Dissolve in fat
Can be stored
Water-soluble
Dissolve in water
Carried in
bloodstream, not
stored
A, D, E, K
C and B-complex
vitamins
A and D excess can be Excess amounts may
harmful
cause extra work on
kidneys
E and K usually not
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
Deficiency
lead 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 process
Availability
 increases slightly during baking due to alkaline
conditions (baking powder)
Loss
 occurs in cooking water due to leaching.
Pyridoxine (B6)

Functions:



Helps body make nonessential 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)





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

Functions:

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 toxicity
 Not 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 A
Loss

High temperatures and oxygen affect stability. quite stable in
food processing and storage
Vitamin D (the sunshine vitamin)

Functions:

Sources:

Promotes absorption of
calcium and phosphorus


Responsible for calcium
deposition in bone matrix

Regulates cell growth
Plays role in immunity





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
food
:phosphate ratio should be 1 in
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
