milk composition ii

8/14/2019 Milk Composition II

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Minerals:Minerals:

Although present in small quantities, exertAlthough present in small quantities, exert

considerable influence on the physico- chemicalconsiderable influence on the physico- chemicaland nutritive profile of milk and nutritive profile of milk

Part of the mineral salts occur in true solution,Part of the mineral salts occur in true solution,

while others are in colloidal statewhile others are in colloidal stateAll 22 minerals considered essential to theAll 22 minerals considered essential to the

human diet are present in milk. These include 3human diet are present in milk. These include 3

families of salt:families of salt:1.1. Na,K,Cl: these free ions are negatively Na,K,Cl: these free ions are negatively

correlated to lactose to maintain osmoticcorrelated to lactose to maintain osmotic

equilibrium of milk with bloodequilibrium of milk with blood



2. Ca,Mg,P(i) & citrate: This group consists of 2/32. Ca,Mg,P(i) & citrate: This group consists of 2/3

Ca,1/3 Mg,1/2 P(i) and <1/10 citrate in colloidalCa,1/3 Mg,1/2 P(i) and <1/10 citrate in colloidal(non-diffusible) form & present in casein micelle.(non-diffusible) form & present in casein micelle.

3. Diffusible salts of Ca,Mg, citrate & Po3. Diffusible salts of Ca,Mg, citrate & Po44 – these – these

salts are pH dependant and contribute to overallsalts are pH dependant and contribute to overallAcid base equilibrium of milk Acid base equilibrium of milk



THE MINERAL CONTENT OF FRESH MILK

Mineral Content Per litre

Sodium (mg) 350-900

Potassium (mg) 1100-1700

Chloride (mg) 900-1100

Calcium (mg) 1100-1300

Magnesium (mg) 90-140

Phosphorous (mg) 900-1000

Zinc (ug) 2000-6000

Copper (ug) 100-600

Manganese (ug) 20-50

Iodine (ug) 260



MINERAL CONTENT OF MILK MINERAL CONTENT OF MILK Mineral Content Per litre

Fluoride (UG) 30-220

Selenium (ug) 5-67

Cobalt (ug) 0.5-1.3

Chromium (ug) 8-13

Molybdenum (ug) 18-120

Nickel (ug) 0-50

Silicon (ug) 750-7000

Vanadium (ug) Tr-310

Tin (ug) 40-500

Arsenic (ug) 20-60



Nutritional value:Nutritional value:

Minerals have a high NV.Minerals have a high NV.

Consumption of modest ~60 g of SMP providesConsumption of modest ~60 g of SMP provides

RDA for Ca and P(75%)RDA for Ca and P(75%)

Dietary ca widely recognized a key factor inDietary ca widely recognized a key factor in˜ Healthy bone development in foetus &˜ Healthy bone development in foetus &

Children.Children.

˜ Development of osteoporosis in post – ˜ Development of osteoporosis in post – menopausal women.menopausal women.

Milk is an excellent source of dietary CaMilk is an excellent source of dietary Ca



Its association with phosphorylated caseinsIts association with phosphorylated caseins

improves its absorption from the GIT.improves its absorption from the GIT.

Phosphopeptides released during digestion of Phosphopeptides released during digestion of casein increases the conc. of soluble Ca in thecasein increases the conc. of soluble Ca in the

intestine - enhanced bioavailabilityintestine - enhanced bioavailability

Milk is also rich in a wide range of elementsMilk is also rich in a wide range of elements Trace element requirements significantlyTrace element requirements significantly

contributed by milk in the form of Mg, Zn,contributed by milk in the form of Mg, Zn,

Se,Mb and I.Se,Mb and I.



Minor Milk Constituents:Minor Milk Constituents:

PhospholipidsPhospholipids (0.2-1.0%)(0.2-1.0%)

Present in FGM & Milk serum.Present in FGM & Milk serum.

Three types viz., lecithin, cephalin andThree types viz., lecithin, cephalin and

sphingomyelinsphingomyelin

LecithinLecithin

~forms an imp. Constituent of FGM~forms an imp. Constituent of FGM

~contributes to the richness of flavor of milk ~contributes to the richness of flavor of milk

and other dairy productsand other dairy products

~ Highly sensitive to oxidative deterioration~ Highly sensitive to oxidative deterioration

giving rise to oxidative/ metallic flavors.giving rise to oxidative/ metallic flavors.



PL are excellent emulsifying agents and servePL are excellent emulsifying agents and serve

to stabilize milk fat emulsionto stabilize milk fat emulsion

Cholesterol (0.25-0.40%)Cholesterol (0.25-0.40%) In complex formation with proteins in the non-In complex formation with proteins in the non-

fat portion of milk.fat portion of milk.

Present as part of the FGM complex in fatPresent as part of the FGM complex in fat

portion of milk portion of milk

PigmentsPigments

i.i. Fat soluble- carotene, xanthophylFat soluble- carotene, xanthophyl

ii.ii. water soluble – riboflavinwater soluble – riboflavin



Carotene is responsible for the yellowCarotene is responsible for the yellow

colour of milk, cream, butter, ghee and other colour of milk, cream, butter, ghee and other

fat rich dairy products.fat rich dairy products. Acts as an antioxidantActs as an antioxidant

Precursor of Vit.A.Precursor of Vit.A.

Has two forms alpha and Beta, the former Has two forms alpha and Beta, the former

yields one while latter yields two moleculesyields one while latter yields two molecules

of Vit.A.of Vit.A.

Dairy animals differ in their capacity toDairy animals differ in their capacity totransfer carotene from feed to milk fat.transfer carotene from feed to milk fat.



This varies with Species,breed andThis varies with Species,breed and

individuality.individuality.

cows in general and some breeds in particular cows in general and some breeds in particular (Guernsey, jersey) can transfer more carotene(Guernsey, jersey) can transfer more carotene

from feed to milk fat compared to buffaloes.from feed to milk fat compared to buffaloes.

Buffalo milk is whiter in colour Buffalo milk is whiter in colour

(carotenoid content 0.25-0.48ug/g vs. cow milk (carotenoid content 0.25-0.48ug/g vs. cow milk

~30ug/g)~30ug/g)

Riboflavin, besides being a Vit. is a greenishRiboflavin, besides being a Vit. is a greenishyellow pigment- gives characteristic colour toyellow pigment- gives characteristic colour to

wheywhey



Enzymes:Enzymes:

Milk is rich in native enzymesMilk is rich in native enzymes

About 50 different enzyme activities areAbout 50 different enzyme activities are

reported- only a small number has significance.reported- only a small number has significance.

Lipoprotein LipaseLipoprotein Lipase

Principal lipase in milk Principal lipase in milk

catalyzes the hydrolysis of TG to FFAcatalyzes the hydrolysis of TG to FFA

Present in appreciable quantities in freshlyPresent in appreciable quantities in freshlydrawn milk.drawn milk.

Pronounced reactions lead to production of Pronounced reactions lead to production of

soapy, bitter, rancid and unclean flavorssoapy, bitter, rancid and unclean flavors



Spoilage by this enzyme prevented by twoSpoilage by this enzyme prevented by two

factors:factors:

~ FGM-acts as a physical barrier ~ FGM-acts as a physical barrier ~ Heat treatment readily destroys lipase~ Heat treatment readily destroys lipase

Spontaneous lipolysis rare and occurs due toSpontaneous lipolysis rare and occurs due to

factors like ,factors like ,

~ Stage of lactation~ Stage of lactation

~Season~Season

~ diet~ diet

~ Plane of nutrition~ Plane of nutrition



PlasminPlasmin

Major milk proteinaseMajor milk proteinase

Has a trypsin like activityHas a trypsin like activity Identical to blood plasmin and conc in milk Identical to blood plasmin and conc in milk

associated with blood conc.associated with blood conc.

High milk plasmin is seen in conditions likeHigh milk plasmin is seen in conditions like

~ Early lactation~ Early lactation

~ Late lactation~ Late lactation

~ Udder diseases~ Udder diseases



(Leakage of blood components into milk)(Leakage of blood components into milk)

Index of high plasimn activityIndex of high plasimn activity

~ High levels of gamma casein~ High levels of gamma casein~ Bacteriologically sound milk ~ Bacteriologically sound milk

At neutral pH heat stableAt neutral pH heat stable

Survives pasteurization / UHT treatmentSurvives pasteurization / UHT treatment

LactoperoxidaseLactoperoxidase

Present in high concentrationsPresent in high concentrations

Catalyzes transfer of OCatalyzes transfer of O22 from Hfrom H

22 OO22 to other to other

substrates like Thiocyanatesubstrates like Thiocyanate



Has potential to catalyze oxidation of USFAHas potential to catalyze oxidation of USFA

leading to development Of oxidized flavour leading to development Of oxidized flavour

Extraneous addition of SCN and HExtraneous addition of SCN and H22 oo22 in milk – in milk – acts as a powerful bactericide.acts as a powerful bactericide.

Short term preservation of milk in developingShort term preservation of milk in developing

countries where refrigeration is scarce.countries where refrigeration is scarce.

Xanthin OxidaseXanthin Oxidase

Catalyzes Non- Specific oxidation of dairyCatalyzes Non- Specific oxidation of dairy

products products Overall significance is not high.Overall significance is not high.



Alkaline PhosphataseAlkaline Phosphatase

Completely inactivated by pasteurizationCompletely inactivated by pasteurization

used as index of efficiency of pasteurizationused as index of efficiency of pasteurization

VitaminsVitamins

Essential for many life processesEssential for many life processes Substantial quantities found in milk Substantial quantities found in milk

~ Fat soluble –A,D,E,K ~ Fat soluble –A,D,E,K

~ water soulble B1,B2, B6, B12, niacin,~ water soulble B1,B2, B6, B12, niacin, pantothenic acid, biotin, folic acid pantothenic acid, biotin, folic acid



Factors affecting concentration.Factors affecting concentration.

~ Seasonal changes~ Seasonal changes

~Breed~Breed

~ Diet~ Diet

Vitamins readily affected byVitamins readily affected by

~ Light~ Light

~ Processing (Deteriorates,A,B~ Processing (Deteriorates,A,B22, C), C)

~ Fat soluble – stable~ Fat soluble – stable



VITAMIN CONTENT OF MILK

Vitamin Contents per litre

A (ug RE) 400

D (IU) 40

E (ug) 1000

K (ug) 50

B1 (ug) 450B2 (ug) 1750

Niacin (ug) 900

B6 (ug) 500

Pantothenic acid (ug) 3500

Biotin (ug) 35

Folic acid (ug) 55

B12 (ug) 4.5

C (mg) 20



UreaUrea

Responsible for Seasonal variation in heatResponsible for Seasonal variation in heat

stabilitystability Conc. In milk controlled by conc. In bloodConc. In milk controlled by conc. In blood

which in turn is controlled by diet.which in turn is controlled by diet.

Mechanism by which urea influences heatMechanism by which urea influences heatstability :stability :

urea decompose on heating to yield isocyanateurea decompose on heating to yield isocyanate

which reacts with free SH groups in WP and/or which reacts with free SH groups in WP and/or Kappa caseinKappa casein

High levels of urea are associated with veryHigh levels of urea are associated with very

stable milk.stable milk.



Milk is considered aMilk is considered a near complete singlenear complete single

food in naturefood in nature because it contains almost all because it contains almost allessential nutrients required for growth andessential nutrients required for growth anddevelopment in adequate and assimilable forms.development in adequate and assimilable forms.

Considered asConsidered as chief protective foodchief protective food because it because ithas abundant vitamins and calciumhas abundant vitamins and calcium



ColostrumColostrum Syn. BiestingsSyn. Biestings

First secretion drawn immediately after parturitionFirst secretion drawn immediately after parturition Thick viscid fluid differing greatly in compositionThick viscid fluid differing greatly in composition

from that of milk obtained a week after calvingfrom that of milk obtained a week after calving

Characterized by:Characterized by:~ High proportion of albumin & globulin~ High proportion of albumin & globulin

~higher ash content~higher ash content

~ lower lactose content~ lower lactose content



The change from colosrtrum to milk is gradual andThe change from colosrtrum to milk is gradual and

there is a progressive/ regular fall in:there is a progressive/ regular fall in:

~Chloride~Chloride

~ Ash~ Ash

~ Total Nitrogen~ Total Nitrogen

~ Casein~ Casein~ Albumin + Globulin~ Albumin + Globulin

~ Dry matter ~ Dry matter

~ Specific gravity~ Specific gravity~ TA~ TA

FP Practically constantFP Practically constant

Lactose variable & Fat irregular Lactose variable & Fat irregular



The most striking difference between milk andThe most striking difference between milk andcolostrums is the high globulin content whichcolostrums is the high globulin content whichcauses milk to coagulate on boiling ;alsocauses milk to coagulate on boiling ;alsoinfluenced by salt imbalance and lower heatinfluenced by salt imbalance and lower heatStability.Stability.

Iron content of colostrum is -10-17-timesIron content of colostrum is -10-17-times

higher than normal milk.higher than normal milk. Higher proline content of globulin.Higher proline content of globulin. Significant from the aspect of Hb production inSignificant from the aspect of Hb production in

newly born.newly born. Fat of colostrum compared to milk has :Fat of colostrum compared to milk has :



˜̃ 9 times9 times CarotoneCarotone

˜ 8 times˜ 8 times Vit AVit A

˜ two times˜ two times Vit DVit D

Functions:Functions:

Hb production in rapidly growing new bornsHb production in rapidly growing new borns Passive immunity conferred by transfer of Passive immunity conferred by transfer of

maternal antibodies to offspring'smaternal antibodies to offspring's

Facilitates faecal excretionFacilitates faecal excretion



Composition of colostrumsComposition of colostrumsConstituents Range of Occurrence

Water 75-78%Total Protein 16-18%

Casein 4-5%

Albumin & Globulin 12-13%

Fat 4-5%

Lactose 2-2.5%

Mineral Matter 1-1.6%

Specific gravity 1.046%- 1.079

Total Solids 22-25%

milk composition ii

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