MILKMILK PRODUCTS

COMPOSITION OF MILK

Water - 87-88%Water - 87-88% Total milk solids - 12-13%Total milk solids - 12-13%

CARBOHYDRATE – 5%

Lactose – main CHOLactose – main CHO Low solubility, may precipitate out Low solubility, may precipitate out

as grainy substance during heat as grainy substance during heat treatmentstreatments

Converts to lactic acid with Converts to lactic acid with souring or fermentation – lactose souring or fermentation – lactose stays in wheystays in whey

Part of milk solids non fatPart of milk solids non fat Less sweet than sucroseLess sweet than sucrose

FAT

3-4% for whole milk, varies according to state 3-4% for whole milk, varies according to state lawlaw

Primarily triglycerides, then phospholipids, Primarily triglycerides, then phospholipids, sterolssterols

Mix of unsaturated, monounsaturated, Mix of unsaturated, monounsaturated, polyunsaturatedpolyunsaturated

High level of short chain – contribute to milk High level of short chain – contribute to milk flavor and low melting point of butterflavor and low melting point of butter

Fat globules less dense than water Fat globules less dense than water less stable less stable Milk is an emulsionMilk is an emulsion ““Creaming” process – fat rises to the topCreaming” process – fat rises to the top

PROTEINS

CASEIN

Primary proteinPrimary proteingroup of similar group of similar proteins – micellular proteinsproteins – micellular proteins

Colloidally dispersed, poorly hydrated, Colloidally dispersed, poorly hydrated, calcium sensitive, excellent emulsifierscalcium sensitive, excellent emulsifiers

Can be separated by acidification to bring Can be separated by acidification to bring to isoelectric point (4.6)to isoelectric point (4.6)

RenninRennin- enzyme also precipitates - enzyme also precipitates caseincasein clotting, clabbering, curdling clotting, clabbering, curdling when milk sourswhen milk sours

WHEY

Lactalbumin and lactoglobulinLactalbumin and lactoglobulin More hydrated than casein, denatured More hydrated than casein, denatured

and precipitated by heat >60and precipitated by heat >6000C or 140C or 14000F F forms scum on bottom of pan forms scum on bottom of pan scorches scorches

Not precipitated with acid or rennetNot precipitated with acid or rennet Lactose precipitates with the wheyLactose precipitates with the whey Enzymes – lipase, protease, alkaline Enzymes – lipase, protease, alkaline

phosphatasephosphatase Casein and whey part of milk solids non Casein and whey part of milk solids non

fatfat

VITAMINS

Fat soluble - naturally in fat Fat soluble - naturally in fat component in whole milkcomponent in whole milk

High in vitamin A, some DHigh in vitamin A, some D Fair source of water soluble Fair source of water soluble

vitamins (B), excellent riboflavinvitamins (B), excellent riboflavin Small amounts of vitamin CSmall amounts of vitamin C Fortified with Vitamin A and DFortified with Vitamin A and D

MINERALS

CalciumCalcium PhosphorusPhosphorus MagnesiumMagnesium PotassiumPotassium SodiumSodium Chloride Chloride SulfurSulfur

PIGMENTS

Fresh whole milk Fresh whole milk ivory caused ivory caused by refraction of light in dispersed by refraction of light in dispersed particlesparticles

Skim milk Skim milk bluish cast bluish cast Carotene and riboflavinCarotene and riboflavin yellow yellow

tingetinge Riboflavin Riboflavin green tone green tone

FLAVOR OF MILK

Mouthfeel due to emulsified fat, Mouthfeel due to emulsified fat, colloidally dispersed proteins, lactose, colloidally dispersed proteins, lactose, milk saltsmilk salts

Fresh milk contains acetone, Fresh milk contains acetone, actealdehyde, methyl ketones, and actealdehyde, methyl ketones, and short chain fatty acids to provide short chain fatty acids to provide aromaaroma

Normally a mild sweet flavorNormally a mild sweet flavor Heat processing changes flavorHeat processing changes flavor Affected by physical condition of cow Affected by physical condition of cow

and composition of the feedand composition of the feed

OFF FLAVORS

Main cause Main cause pasture weeds pasture weeds Old or moldy feed Old or moldy feed rancid or bitter rancid or bitter

flavorsflavors Oxidation of fat Oxidation of fat oxidized oxidized

phospholipidsphospholipids

fishy odorsfishy odors Exposure to sunlight changes Exposure to sunlight changes

riboflavin and milk proteinsriboflavin and milk proteins

CLASSIFICATION OF MILK

SOLUTION

Sugar - lactoseSugar - lactose Water-soluble vitamins thiamin Water-soluble vitamins thiamin

& riboflavin& riboflavin Mineral salts, and mineralsMineral salts, and minerals

COLLOIDAL DISPERSION

Casein bound to calcium Casein bound to calcium phosphate in micelle - too big to phosphate in micelle - too big to dissolve dissolve

Whey proteinsWhey proteins

EMULSION

Unstable due to large droplet Unstable due to large droplet phase of fats, temporaryphase of fats, temporary

MILK PROCESSING

SANITATION AND QUALITY

PHFPHF Grade A Pasteurized Milk OrdinanceGrade A Pasteurized Milk Ordinance USDA, US Public Health Service (FDA) and USDA, US Public Health Service (FDA) and

state departments of agriculture regulate state departments of agriculture regulate milk and milk productsmilk and milk products

Voluntary Voluntary

GRADES

Grade A – available to consumer – fluid Grade A – available to consumer – fluid milkmilk

Grade B & C higher bacterial count, Grade B & C higher bacterial count, safe, wholesomesafe, wholesome

Grade US extra and US standard used Grade US extra and US standard used for dried milkfor dried milk

Grades based on bacterial count of Grades based on bacterial count of fresh milkfresh milk

Given on a voluntary fee for service Given on a voluntary fee for service basisbasis

PASTEURIZATION

Treating with heat to kill pathogens and Treating with heat to kill pathogens and inactivate spoilage enzymes; some inactivate spoilage enzymes; some spoilage organisms may survive so cool spoilage organisms may survive so cool promptly and hold under refrigerationpromptly and hold under refrigeration

Destroys lipase which catalyzes Destroys lipase which catalyzes hydrolytic rancidityhydrolytic rancidity

Process is time/temperature dependentProcess is time/temperature dependent Alkaline phosphatase - same heat Alkaline phosphatase - same heat

denaturation curve as milk pathogens; denaturation curve as milk pathogens; presence indicates inadequate presence indicates inadequate pasteurizationpasteurization

TIME/TEMPERATURES

Use high temperature, short time Use high temperature, short time (H.T.S.T.) 162F, 72C for 15 seconds(H.T.S.T.) 162F, 72C for 15 seconds

Low temperature longer timeLow temperature longer time Ultra-high temperature (U.H.T.) - Ultra-high temperature (U.H.T.) -

growing, 280F for 2-4 sec. May growing, 280F for 2-4 sec. May develop cooked flavor, use in shelf develop cooked flavor, use in shelf stable products, often used with stable products, often used with cream, eggnog, half and halfcream, eggnog, half and half

STERILIZATION

Only occurs with ultra-high Only occurs with ultra-high temperatures for 2-6 secondstemperatures for 2-6 seconds

Can be aseptically packaged; no Can be aseptically packaged; no refrigeration until openedrefrigeration until opened

HOMOGENIZATION

Prevents creaming; maintains more uniform Prevents creaming; maintains more uniform composition, optional processcomposition, optional process

Mechanically reduces size, increases number of fatMechanically reduces size, increases number of fat globulesglobules permanently emulsifies fat globules permanently emulsifies fat globules Characteristics: Characteristics: Whiter milk Whiter milk More viscous, creamy milkMore viscous, creamy milk More bland - fat globules smallerMore bland - fat globules smaller Less stable to lightLess stable to light Increased chance of rancidityIncreased chance of rancidity

  

FORTIFICATION

Whole milk - optional addition of A & DWhole milk - optional addition of A & D Lowfat milk, nonfat, low-fat chocolate - Lowfat milk, nonfat, low-fat chocolate -

Must be fortified for AMust be fortified for A Addition of D optional but routinely Addition of D optional but routinely

practicedpracticed To increase viscosity, appearance, and To increase viscosity, appearance, and

nutritive value of lowfat milk, nonfat nutritive value of lowfat milk, nonfat milk solids may be added – states milk solids may be added – states protein fortified or fortified with proteinprotein fortified or fortified with protein

BLEACHING

FDA - benzoyl peroxide or benzoyl FDA - benzoyl peroxide or benzoyl peroxide with potassium alum, peroxide with potassium alum, calcium sulfate, and magnesium calcium sulfate, and magnesium carbonate to be used as a bleaching carbonate to be used as a bleaching agent in milk to remove pigments agent in milk to remove pigments such as carotenoids and chlorophyllssuch as carotenoids and chlorophylls

Vitamin A or precursors may be Vitamin A or precursors may be destroyed destroyed sufficient A added into sufficient A added into milk or curd (for cheesemaking)milk or curd (for cheesemaking)

TYPES OF MILK

FLUID

Must be free of pathogenic bacteriaMust be free of pathogenic bacteria Fat content and % of MSNF subject to FDA Fat content and % of MSNF subject to FDA

regulationsregulations Flavored – same nutrients as milk to which Flavored – same nutrients as milk to which

flavor addedflavor added Certified milk – limited distribution due to Certified milk – limited distribution due to

cost, sanitary standards very highcost, sanitary standards very high Eggnog- mixture of dairy ingredients Eggnog- mixture of dairy ingredients

(cream, milk) egg yolk containing (cream, milk) egg yolk containing ingredients, nutritive carbohydrate ingredients, nutritive carbohydrate sweeteners.sweeteners.

OTHER FLUID MILK

Canned whole milk – homogenized, sterilized, Canned whole milk – homogenized, sterilized, canned asepticallycanned aseptically

Frozen whole milk – homogenized, pasteurized, fat Frozen whole milk – homogenized, pasteurized, fat separates when thawed, protein denatured by separates when thawed, protein denatured by freezingfreezing

Skim or nonfat – as much fat as possible removed, Skim or nonfat – as much fat as possible removed, minimum of MSNF, fortified with vitamin A. minimum of MSNF, fortified with vitamin A. Optional: vitamin D, emulsifiers, stabilizersOptional: vitamin D, emulsifiers, stabilizers

Low-fat milk – some fat removed, named Low-fat milk – some fat removed, named according to fat remaining, minimum MSNF, according to fat remaining, minimum MSNF, fortified with vit. A. Optional: Vit. D, emulsifiers, fortified with vit. A. Optional: Vit. D, emulsifiers, stabilizersstabilizers

Labeled with protein fortified if MSNF >10%Labeled with protein fortified if MSNF >10%

CONCENTRATED MILKS

EVAPORATED MILK

Concentrated through process of Concentrated through process of evaporationevaporation

Evaporated in a vacuum chamberEvaporated in a vacuum chamber Whole or nonfat – 60% of HWhole or nonfat – 60% of H22O removedO removed Homogenized, fortified, canned, Homogenized, fortified, canned,

sterilizedsterilized Increasingly less stable with progression Increasingly less stable with progression

of concentration and heat of concentration and heat may may coagulate coagulate prevent by forewarming prevent by forewarming

Maillard reaction Maillard reaction light tan color light tan color Reconstitute 1:1 ratioReconstitute 1:1 ratio

CONDENSED MILK

Similar in content and use to Similar in content and use to evaporated milkevaporated milk

NOT sterilizedNOT sterilized Perishable at temperatures above Perishable at temperatures above

454500FF

SWEETENED CONDENSED MILK

Concentrated whole or nonfat milkConcentrated whole or nonfat milk 60% of H60% of H22O removedO removed Sweetened with sucrose or dextrose Sweetened with sucrose or dextrose

prior to concentrationprior to concentration 40-45% sugar level, may cause 40-45% sugar level, may cause

grittinessgrittiness Pasteurized, not sterilized due to high Pasteurized, not sterilized due to high

concentration of sugarconcentration of sugar Used in pie filling – thickening occurs Used in pie filling – thickening occurs

because concentrated proteins because concentrated proteins coagulate from the effect of added acidcoagulate from the effect of added acid

DRIED MILK

Processed from whole or nonfat milk Processed from whole or nonfat milk (more common)(more common)

Condensed 2/3 of HCondensed 2/3 of H22O removedO removed Sprayed into heated vacuum chamber Sprayed into heated vacuum chamber

less than 5% moisture level less than 5% moisture level Most nonfat fortifiedMost nonfat fortified ““Instant” or “agglomerated” – some Instant” or “agglomerated” – some

moisture added backmoisture added back pourable, pourable, dispersible, in cold Hdispersible, in cold H22OO

May also dry buttermilk, wheyMay also dry buttermilk, whey

CULTURED AND FERMENTED MILK AND

MILK PRODUCTS

CULTURED/FERMENTED

Cultured products fermented by Cultured products fermented by addition of bacterial cultures-addition of bacterial cultures-Streptococci and LactobacilliStreptococci and Lactobacilli

Ferment lactose Ferment lactose lactic acid; create lactic acid; create low pH to coagulate caseinlow pH to coagulate casein

Acidified products – souring milk with Acidified products – souring milk with acid, with or without microorganismsacid, with or without microorganisms

Cultured and acidified products Cultured and acidified products contain different amounts of lactic contain different amounts of lactic acid acid different flavors different flavors

BUTTERMILK

Traditionally liquid left after churning Traditionally liquid left after churning butter, differs from nonfat milk due to butter, differs from nonfat milk due to content of phospholipids and proteins content of phospholipids and proteins from fat globule, NFDM solids addedfrom fat globule, NFDM solids added

Cultured buttermilk – pasteurized Cultured buttermilk – pasteurized lowfat or nonfat milk with Lactobacilli lowfat or nonfat milk with Lactobacilli and Streptococci addedand Streptococci added

Acidified buttermilk – lactic acid Acidified buttermilk – lactic acid producing bacteria not compulsoryproducing bacteria not compulsory

Smooth cultured flavor, high acid Smooth cultured flavor, high acid content useful in cookingcontent useful in cooking

SOUR CREAM

Traditionally heavy cream souredTraditionally heavy cream soured Pasteurized, homogenized fresh Pasteurized, homogenized fresh

light creamlight cream Coagulated similar to buttermilkCoagulated similar to buttermilk Flavors, stabilizers addedFlavors, stabilizers added Proteolytic bacterial enzyme Proteolytic bacterial enzyme

activity may cause bitter flavor activity may cause bitter flavor after 3-4 weeksafter 3-4 weeks

YOGURT

Culture pasteurized dairy product with Culture pasteurized dairy product with lactobacillus bulgaricus and lactobacillus bulgaricus and streptococcus thermophilisstreptococcus thermophilis

National Yogurt Association seal for live National Yogurt Association seal for live and active bacteria; at least 100 million and active bacteria; at least 100 million bacteria/gram at time of manufacturebacteria/gram at time of manufacture

Yogurt with viable strains of bacteria Yogurt with viable strains of bacteria eaten in sufficient quantities some will eaten in sufficient quantities some will survive passage through stomach and survive passage through stomach and release lactase in the intestinerelease lactase in the intestine

OTHER PRODUCTS

Acidophilus milk - pasteurized low-fat or nonfat Acidophilus milk - pasteurized low-fat or nonfat milk with Lactobacillus Acidophilus added, milk with Lactobacillus Acidophilus added, Bacteria can live in intestine and produce Bacteria can live in intestine and produce number of B vitaminsnumber of B vitamins

Reduced Lactose milk - pasteurized milk Reduced Lactose milk - pasteurized milk treated with lactasetreated with lactase

sweeter than regular milksweeter than regular milk Kefir– fermented dairy products, kefir grain Kefir– fermented dairy products, kefir grain

yields bacteria added to milkyields bacteria added to milk Koumiss – milk heated before fermentationKoumiss – milk heated before fermentation Ferments to yield soft curd with yeasty sour Ferments to yield soft curd with yeasty sour

curd with mild alcoholic flavorcurd with mild alcoholic flavor

MILK SUBSTITUTES

Imitation milk – combination of Imitation milk – combination of several nondairy ingredients; several nondairy ingredients; nutritionally inferiornutritionally inferior

Substitute milk – nutritionally Substitute milk – nutritionally equivalent; reduced calories or equivalent; reduced calories or fat, usually milk derivatives fat, usually milk derivatives ( casein, casein salts, whey)( casein, casein salts, whey)

Filled milk – substitute milk with Filled milk – substitute milk with milkfat replaced with vegetable oilmilkfat replaced with vegetable oil

CREAMS

DESCRIPTION

High fat component separated High fat component separated from milkfrom milk

Federal standards must have at Federal standards must have at least 18% milkfatleast 18% milkfat

Yellow, fat-soluble pigments visibleYellow, fat-soluble pigments visible

TYPES

Light coffee cream – 18-30%Light coffee cream – 18-30% Light whipping cream – 30-36%Light whipping cream – 30-36% Heavy cream – 36% butterfat, Heavy cream – 36% butterfat,

minimumminimum Half and half – cream diluted with Half and half – cream diluted with

nonfat milk 10.5%nonfat milk 10.5%

PRINCIPLES OF USING MILK AND MILK PRODUCTS

EFFECTS OF HEAT

Prolonged heating adversely affects:Prolonged heating adversely affects: Flavor – dependent on length of time of Flavor – dependent on length of time of

heating and temperature reachedheating and temperature reached Due to production of sulfur compounds Due to production of sulfur compounds

from denaturation of whey proteinsfrom denaturation of whey proteins Due to caramelized flavor from Maillard Due to caramelized flavor from Maillard

reactionreaction OdorOdor Cooking propertiesCooking properties

HEAT AND MILK PROTEINS

Heated milk forms precipitate on bottom Heated milk forms precipitate on bottom and sides of pan – coagulated whey and sides of pan – coagulated whey proteinsproteins

Precipitated proteins tend to scorchPrecipitated proteins tend to scorch One whey protein component produces a One whey protein component produces a

low volume in yeast breads made with low volume in yeast breads made with unheated milk- scalded milk unheated milk- scalded milk greater greater volume in yeast breadsvolume in yeast breads

Heated in uncovered pan forms “skin” – Heated in uncovered pan forms “skin” – coagulated proteins, fat, minerals because coagulated proteins, fat, minerals because milk drying out on topmilk drying out on top

Prevents steam from escaping Prevents steam from escaping boil over boil over

HEAT AND MILK PROTEINS

Casein changes little under normal Casein changes little under normal heatingheating

May not take place until milk has been May not take place until milk has been boiled for 14 hoursboiled for 14 hours

Temperatures above boiling Temperatures above boiling cleavage of peptide and phosphate cleavage of peptide and phosphate bondsbonds

In concentrated milks coagulation In concentrated milks coagulation greater due to protein concentrationgreater due to protein concentration

Unstable emulsion like soured milks Unstable emulsion like soured milks accelerate coagulation with heataccelerate coagulation with heat

HEAT AND MILK MINERALS

Decreases dispersion of Decreases dispersion of calcium phosphatecalcium phosphate

Precipitates and becomes Precipitates and becomes enmeshed in whey proteins enmeshed in whey proteins on bottom of panon bottom of pan

EFFECT OF ACID

Normal pH = 6.5-6.7Normal pH = 6.5-6.7 Add acid Add acid pH decreases pH decreases Below 5.1 casein destabilizesBelow 5.1 casein destabilizes At pH 4.5 casein salts formed At pH 4.5 casein salts formed milk curdles milk curdles Coagulum traps whey which is released when curd Coagulum traps whey which is released when curd

is cut, stirred, or heatedis cut, stirred, or heated Curd is soft, fragileCurd is soft, fragile Cheese from acid coagulation is low in calcium Cheese from acid coagulation is low in calcium

compared to wheycompared to whey Cream of tomato soup – separates milk proteinsCream of tomato soup – separates milk proteins Acids in fruits curdle milk in smoothiesAcids in fruits curdle milk in smoothies Add lemon juice to sauce at end of cookingAdd lemon juice to sauce at end of cooking

EFFECT OF ENZYMES

Coagulate proteinsCoagulate proteins Clabbered by rennin – stomach of Clabbered by rennin – stomach of

milk-fed calves – extract is rennet, milk-fed calves – extract is rennet, now use pepsin from hog stomachsnow use pepsin from hog stomachs

Genetically engineered rennet from Genetically engineered rennet from genetically modified Aspergillus moldgenetically modified Aspergillus mold

Clots are tough, rubbery, contain Clots are tough, rubbery, contain most of calciummost of calcium

Add to warm milk for optimal activityAdd to warm milk for optimal activity

EFFECT OF ALKALI

Baking soda, for exampleBaking soda, for example Stabilizes colloidal Stabilizes colloidal

dispersionsdispersions

EFFECT OF POLYPHENOLIC COMPOUNDS

TanninsTannins Astringent compounds found Astringent compounds found

in fruit, vegetables, plant in fruit, vegetables, plant foodsfoods

Produce curdling especially if Produce curdling especially if soured or destabilized by soured or destabilized by heatheat

Potatoes cause curdling in Potatoes cause curdling in scalloped dishesscalloped dishes

EFFECT OF SALT

In high concentration will In high concentration will destabilize a geldestabilize a gel

Influences coagulation of Influences coagulation of caseincasein

Ham added to milk-based Ham added to milk-based dish high sodium content dish high sodium content curdles surrounding liquidcurdles surrounding liquid