NUFS 374 Course Summary

374 Midterm Summary

MILK PRODUCTS
What influences the quality of milk?
1. Primary raw material and its components (including microbial contents)
2. Primary treatments (as well as manufacturing processes) used in transformation of milk

Criteria that can be used to assess quality of foods including dairy:
1. Sensory: flavor, texture, appearance
2. Microbiological: raw milk contains microorganisms, related to sensory quality and safety)
3. Safety: (shelf life) free of pathogens and chemicals
4. Compositional: basic chemical composition of raw material and by processing e.g. quality of butter made from fat of milk (can’t put in grape seed oil)
5. Physiological functionality, nutrition, technological functionality: qualitative function, whip egg whites, boiled

Solution:
Emulsion:
Colloidal suspension:

Milk composition: the quantities of the various main constituents of milk can vary considerably between cows of different breeds and between individual cows of the same breed. Therefore only limit values can be stated for the variations o Casein &Whey proteins (3.5% w/v): o Casein (80%α+κ+β): in micelles with Ca + P, sensitive to enzymes and acid, does not taste o Whey (20%α+βlactoglobulin): in serum, nutraceutical properties, not acid sensitive, sensitive to heat; more complete protein than casein o During denaturation, casein adheres to beta-lactoglobulin o Lactose (4.8% w/v): disaccharide (glucose + galactose) o limited sweetness (unsuitable as a sweetening agent,can be improved by hydrolysis) o reducing sugar (Maillard rxn upon heating) o limited solubility in water (crystallization in highly concentrated dairy foods: ice cream!, whey cheese, sweetened condensed milk) o bacteria utilize lactose in fermentations (LAB) o Lactose intolerance: do not secrete enough lactase, lactose escapes digestion, builds up in colon and gets fermented; natural occurrence in all mammals. Industry responds:
• Lactose hydrolyzed milk (lactaid, lactese): in vitro breakdown of lactose by enzymes to monosacharides by Beta-Galactosidase o Fat (3.5% w/v; 95% in globules! 36-40g fat in 1L milk; 98% found in TG, 2% other components soluble in fat phospholipids, cholesterol, carotenoids, vitamins ADE, 0.1-0.4% FFA): o Fat globules with globule membranes o Saturated (70%) + Unsaturated (30%: 25% MUFA, 3% TFA): the milk FA are derived almost equally from two sources, the feed and the microbial activity in the rumen of the cow o Size/ behaviour o Density, creaming o Sensory effects o Health effects o Soluble in organic solvents o Minerals (Ca + P) (1% w/v): soluble (NaCl), colloidal (Ca) o Free and micelar calcium: holds micelles together, related to cheese making, gel formation o Most abundant = potassium o Water (87% w/v): solvent (solutes decrease freezing point) o Other compounds: o Enzymes: plasmin, lipase, alkaline phosphatase (role in cheese ripening)
• Proteases, proteinases, peptidases; major protease is Plasmin: some are inactivated by heat and some not. Protein degradation can be undesirable and result in bitter off-flavor or it may provide a desirable texture to cheese during ripening.
• Lipase: agitation during processing may bring LPL into contact with the milk fat resulting in fat degradation and off-flavors. Pasteurization will inactivate the lipase in milk and increase shelf life
• Phosphatase (alkaline, acid): heat sensitive enzyme used as indicator of pasteurization. If properly pasteurized, alkaline phosphatase (and lactoperoxidase) is inactivated o Microbial enzymes: psychrotrophs → spoilage o Vitamins (riboflavin, thiamine, C + D)

Bulk Milk:

Mastitis: microbial infection of the udder
. Accompanied by increases in bacterial numbers (incl. human pathogens)
. Dramatic increase in somatic cells: leukocytes (WBC) + epithelial cells from the udder
. Sub-clinical and clinical mastitis: health aspects, milk yield
. Antibiotics in milk (allergy, antibiotic resistant microorganisms, fermentation)
.

Psychrotrophs still could be a problem (even if rapidly cooled to less than 2 degrees, which would inhibit pathogenic and spoilage bacteria): capable of surviving or thriving in a cold environment
… Bacteria Count in Farm Milk: 5 – 50 thousand is good, 50 – 500 thousand is average, and 0.5 – 5 million is poor (3 days)

Casein Micelle: 2 glues: k-casein & calcium phosphate

Aim of Pasteurization: complete deactivation of vegetative forms of microorganisms (pathogenic, potentially pathogenic, toxicogenic), reduction in numbers of other spoilage organisms, partial deactivation of enzymes; mycobacterium tuberculosis + coxiella burnetii Microorganisms that survive are putrefactive (protein breakdown, acidity development)
Types of Pasteurization:
1. HTST: High Temperature Short Time
a. Minimal conditions: 72°C for 15 seconds
b. Goal: deactivate pathogenic microorganisms (also deactivates other bacteria and enzymes that increase shelf life)
c. Carried out as a continuous process using a plate heat exchanger
i. Corrugated stainless steel plates pressed together ii. Alternate flow of water and milk iii. Rapid transfer of heat because flow is very thin film iv. Rubber gaskets preventing mixing of the two streams
v. To maximize the heat recovery, cold milk is heated by the hot pasteurized milk that is thereby cooled – REGENERATION section. Section can be split with the milk undergoing standardization and or homogenization during this phase vi. Then to holding tube (timing pump) vii. Control thermometer is connected to automatic return valve (improperly pasteurized diverted back to tank)
2. LTH: Low Temperature Holding
a. Batch: 65°C for 30 minutes

Pasteurization < 100 °C • 90-95°C for 1-2 seconds (cream)
• 85-90°C for 1-2 seconds (yogurts, ferment milk)
• 72-74°C for 15-30 seconds (milk) followed by rapid cooling
• 65-68°C for few seconds (cheese, thermization)
• 65°C for 30 minutes (farmhouse) For Sterilizing > 100 °C
Thermization < 100 °C 65 °C for 15 seconds
Ultrapasteurization + no aseptic packaging > 100 °C 120°C for 4 seconds
UHT + aseptic packaging > 100 °C 136°C for 4-8 seconds
Direct heating: steam into milk or milk into steam, condensation releases latent heat (instant heating), expansion temperature returns to atmospheric pressure (instantaneous cooling) *latent heat of condensation = latent heat of vaporization
Indirect heating: pasteurization under pressure (heat exchanger where both fluids are under pressure but heat transfer is not instantaneous)
Technological Heating

Effectiveness of pasteurization for various products:
1. temperature used
2. time of heat exposure
3. the come-up time
4. thickness of the heated layer
5. the nature of the product
6. intensity of mixing during the heat treatment (laminar vs. turbulent)

Chemical changes:
1. some denaturation of whey proteins
2. some destruction of vitamins
3. soluble forms of Ca salts of phosphoric acid transferred onto casein micelles
4. heat treatment at 95C causes noticeable changes of smell and taste resulting from Beta-lactoglobulin SH-groups liberation
5. significant deactivation of vegetative bacteria

Homogenization:
• prevents the formation of a cream layer in full cream milk by a reduction in the size of fat globules to < 1μm leads to at least 10-fold increase in the fat globule area
• as a result the stability of the emulsion is improved (secondary fat globule membrane developed)
• accomplished by equipment called homogenizer
• High pressure homogenization: high pressure, high flow velocity, minimum temperature

Stokes Law: to reduce sedimentation (Velocity approach 0) why standardize bfore homogenize)
- reduce the particle size
- increase viscosity of continuous phase
- minimize the density difference

Increased surface area of fat globules covered by the casein and whey protein molecules

Following usually homogenized:
• market milk
• cream
• condensed milk
• ice cream mixes
• milk for yogurt production
• milk for milk powder production

Impact of homogenization:
• the stability of milk fat emulsion increased, no coalescence of fat droplets, no cream layer formation
• prevents the adhesion of fat on the packaging material surface
• milk with lower fat content has a fuller mouthfeel
• finer consistency in fermented products
• some argument whether it reduces the size of casein micelles, reducing the time of coagulation, leading to softer curd, holding more whey

Fat Separation/Standardization
• continuous centrifuge (disk centrifuge) o one inlet: milk stream o two outlets: skimmed milk moves outward, cream moves inward (20-40% fat) o the two streams mixed to get desired fat content

Elements of UHT Technology
2 stage:
1. sterilization of the product outside the package
2. filling the product into pre-sterilized package
a. deactivation of the microbial life at the UHT conditions does not lead to complete deactivation of enzymes, thus shelf life limited; best before date applies)

Extended Shelf-life Milk (ESL): result of bactofugation (separation of spores and bacterial cell with the high speed centrifuge)

WPN Index: whey protein nitrogen

Evaporators (use heat)
Drier (use heat) Effects:
- lactose: solubility, hygroscopicity, crystallization
- heat load, sensitivity of whey protein
- emulsion characteristics
- flavor losses
- quality effects: solubility, reconstitutability, wettability, instantization

Hygroscopicity: tending of a substance to absorb moisture from the air

The principle constituents of normal salted butter (water-in-oil emulsion):
1. Fat (80-82%)
2. Water (15.6 – 17.6%)
3. Salt (1.2%)
4. Protein, Ca, P (1.2%)
5. Some fat soluble vitamins
- The fat MUST be unadulterated milk fat why?

Sweet cream butter: is butter from cream that is not allowed to sour (just about any butter); should taste of cream
Cultured (sour) cream butter: made from cream fermented by suitable cultures producing lactic acid and diacetyl (silky); should taste of diacetyl. The aroma is richer, the butter yield higher and there is less risk of reinfection after temperature treatment as the bacteria culture suppresses undesirable micro-organisms. If ripening is desired for the production of cultured butter, mixed cultures of S. cremoris, S. lactis var. diacetylactis, or Leuconostoc are used and the cream is ripened to pH 5.5 @ 21C and then pH 4.6 @ 13C. Most flavor development occurs between pH 5.5-4.6; ripening usually takes 12-15hours

SNF = solids non-fat

Butter making is based on the controlled destabilization of the oil-in-water emulsion of cream, selective concentration of the lipid components by removal of the aqueous fraction (buttermilk) and subsequent formation of a stable water-in-oil (semi-solid emulsion). Two principle technological avenues for the conversion of the O/W into W/O emulsion:
1. Churning
a. Traditional batch churning
b. Continuous churning (Fritz process)
2. High-fat content cream (Meleshin process): repeat centrifugation and final conversion Anhydrous milk fat: Butter is at least 80% fat (and the rest is __?). If the rest is removed, the final product is 100% milk fat, no water, thus AMF (in Indian ghee). Ghee is made by melting butter and removing the heavier aqueous phase

Emulsion: a find dispersion of minute droplets of one liquid in another in which it is not soluble or miscible

ICE CREAM:
- A mixture of ice crystals embedded in ..
- Unfrozen highly supersaturated solution that also contains fat clusters and globules
- An emulsion with air whipped in during the freezing process → FOAM

Fermented (cultured) dairy products + cheese
Microbial transformations:
• Lactose: fermented into lactic acid
• Casein: broken down to peptides (manufacture, ripening)
• Fat (transformations during cheese ripening)
• Carbon dioxide, acetic acid, diacetyl, acetaldehyde, ketones, and several other substances are formed in the conversion process, and these give the products their characteristic taste and aroma (cottage cheese/quarg = these include some elements of cheesemaking i.e. separation of whey but no ripening)

Technological transformations
1. Fermented products: one phase – manufacturing
2. Cheese: two phases – manufacturing & ripening (initial acidity development by dairy starter cultures, milk clotting by enzymes, separation of curd (casein and fat) from the liquid (whey) and then ripening (in most cases)
a. Ripening: breakdown of protein, fat, lactose by microorganisms and/or their enzymes, other reactions, mechanical handling

1st Step in cheese making: coagulation of milk casein
1. Acid coagulation:
a. Souring by LAB
b. Addition of acid (lactic acid, tartatic acid, acetic acid, glucono-lactone)
2. Rennet coagulation (breaks down casein)
a. Proteolytic enzymes (produced in any mammalian stomach): chymosin, pepsin
b. Plant enzymes
c. Microbial enzymes
d. From genetically modified engineered vectors.

Does yogurt contain lactose?
Yogurt contain all components? T or F
Why is food preservation important?

Types of preservation: KNOW 3
Fermentation With yeast + glucanoobactor – produces vinegar (a good preservative)
Sterilized
Pasteurized
Dried
Syrup
Frozen
Salting
Smoking
Retorting Process of preserving food by cooking in a sealed airtight container

Question: Criteria for Food Quality

Food Deterioration:
• Loss of safety
• Loss of nutrition
• Low of shelf life
• Loss of organoleptic desirability (acting or involving the use of the sense organs)

Major Causes of Food Deterioration: (occur simultaneously)
1. Biochemical:
a. Growth of microorganisms, bacteria, yeasts, and molds
• Beneficial: LAB, yeast, acetobactor or glucanoobactor, molds
• Spoilage: mold, souring, rancid, lipolysis
• Pathogenic
b. Infestation with insects, parasites, and rodents
• Particularly destructive to cereal grains, FV
• Insects damage tissues and promote microbial infestation.
• Control: GMO, chemicals, CO2, low temp, pulpherize
c. Natural food enzymes
2. Chemical:
a. Oxygen: essential for the growth of molds and most spoilage microbes e.g. oxidation of vitamin C!, change of meat colors, molding, rancidity of fats
b. Moisture – gain or loss of moisture
c. Contaminants (pesticide residues, toxic/heavy metals, etc.)
3. Physical:

a. Inappropriate temperatures
b. Light
c. Handling damage

Infection: toxins produced after invasion into cells (samonella)
Intoxication: toxins released into the food (mold)

How can food be deteriorated with enzymes?
Implications on nutrition/sensory? How can it be prevented?

Food Deterioration, Natural Food enzymes:
• Endo/exo amylases: hydrolyze starch = present in fruits, vegetables (pectin in cell walls), grains o Amylase, pectic enzymes such as pectin methyl esterase, endo, exo, and poly galacturonase causes fruit ripening → addition of Ca can pull COOH groups tight (increase rigidity and handling) o Cathepsins: tenderizing of meat upon aging, active at low pH, act on myofibrils and connective tissue proteins
• Lipase: de-esterify lipids so more prone to oxidation = present in cereals and oilseeds
• Protease: hydrolyze protein
• Lipoxygenase: oxygenate PUFA, oxidizes = present in legumes, cereals, oat, rye
• Pigment degrading enzymes
• Polyphenol oxidase/ Phenolase/ Tyrosinase: enzymes that catalyze oxidation of phenols to orthoquinone which rapidly polymerize to melanin (brown color) → inactivated by blanching, vacuum packaging o Ascorbic acid oxidase: blanching protects vitamin C o Phenols are bound (protect colon) o nitrate protects color

Blanching: 70C for 5-10 seconds, most frozen or cool storage vegetables and fruits. Addition of CaCl2 improves pectin strength and thus texture

Modified Atmospheric Packaging: slow respiration by dropping temperature, decreasing oxygen, and increasing carbon dioxide (fine balance to prevent anaerobic respiration)

GRAIN FOODS

1. Monocotyledoneae (1 seed leaf)
a. Gramineae (family with most cereal grains)
• Wheat (cereal)
• Corn (cereal)
• Rice (cereal)
• Barley (cereal)
• Oat (cereal; monocot)
• Rye (cereal)
b. Palmae
• Coconut
• Palm
2. Dicotyledoneae (2 seed leaf) oil/pulses (Leguminosae)!
• Soybean (oil seed)
• Sesame
• Canola/ Rapeseed/ Mustard (oil seed)
• Sunflower (oil seed)
• Cotton
• Linseed/ flax (oil seed)
• Caster
• Olive

Oil Seeds: Rapeseed is high in erucic acid [LEAR (Low erucic acid rapeseed) & HEAR] and glucosinolate (organic compounds)

Cereals: soft (low in protein) & hard wheat (high in protein/gluten). 70% starch, 13% protein, 14% fibre, 5% fat.

Fractionation: a process that uses heat to separate a substance into its components OR is a separation process in which a certain quantity of a mixture is divided up in a number of smaller quantities in which the composition varies according to a gradient. Fractions are collected based on differences in a specific property of the individual components

• Cotyledon: part of germ (well developed in dicot – starch! protein). “Seed leaf”, is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of seedling. (peanut = cotyledon + root)
• Hull (10-20% cereal; 10-18% oilseeds) ≠ seed coat: not fit for human consumption, damages intestinal wall. Remain attached in rice, barley, oat, but not in wheat. Hull-less varieties are available. Fibrous, high in ash.
• Endosperm (50-83% cereal): major storage (rich in starch and protein). Large thin walled cells. Low in ash, oil, sugars, and fiber.
• Bran (6-15% cereal): taken off by processor, concentrated fiber. Epidermis, epicarp, endocarp. Seed coat, aleurone, oil (20% lipid with lipase/lipoxygenase), protein, enzyme sugars, and low starch
• Cell walls: fiber (fruit; cell wall = pectin)
• Germ/Embryo (2-12% cereal): root and shoot, rich in protein, oil (corn; 30% germ), and B-vitamin/Vitamin E. Major storage organ. *Embryo = 2% root/shoot, 85% cotyledons
• More barriers to starch – lower glycemic index

Gib germ secretes hormone (gibberilus) and enzyme (caleurone) to endosperm → hydrolyze germ?

Hulled: hull-attached
Hull-less barley/oat/wheat: loosely attached, falls off automatically in the field, good invention
Dehulling: grains thrown against rotating metal discs, removes hull, blows air (needly, damage intestines)

Steel-cut oats: structure isn’t disrupted too much, breaks cell walls. No longer a barrier so can get at starch. Starch pebbles are embedded in protein matrix.
Meal: remove hull and grind finally
Flour
Groat: the hulled kernels of various cereal grains such as oat, wheat, and rye. Groats are whole grains that include the cereal germ and fiber-rich bran portion of the grain as well as the endosperm
Pearled barley: remove outer layer coating, abrasive, rough discs – remove bran layer (completely removed, polished, white)
Pot barley: some bran still attached (beta – glucon a SDF)
Wet milling: put in water, crack it by applying grinding technology (blends)
Long rice: high in amylose (makes more compact, linear, resists swelling) STARCH = AMYLOSE + AMYLOPECTIN (starch opens with cooking, fine grinding)
GLUTEN = GLIADIN + GLUTENIN (conjoined with starch in endosperm)

Component Cereals Oilseeds
Starch 55 – 72% -
Protein 8 – 16% 22 – 40% ( soybean)
Lipid 1 – 4% (wheat rye bran 4%, corn 5 %, rice oat 7%) 20 – 45% ( canola)
Fiber (cellulose/hemi)
(β – glucan) 15 – 28%
4 – 7% 30 – 35%
-
Minor Components
Sugars, NPSP, Vitamins, Minerals, Phytic acid, phenolics, enzymes, sterols, pigments, lignans, fructans 1 – 3%
Cinamic acid = coumaric acid + ferulic acid 1 – 5%

Pulse Grains: high in protein (20 – 25%), balanced protein (more than wheat but not 100%), starch (30%). E.g. pinto/kidney beans

Value-added Processing: Rated depending on difficulty. Enhancement to a product before offering the product to customers.
• Primary: milling, pearling, cleaning, polishing
• Secondary: starch extraction, protein isolation, soluble fibre,
• Tertiary: starch modification, protein modification

**Steam inactivates enzymes
• Lipoxygenase: are a family of enzymes that catalyse the dioxgenation of PUFA and especially saturated FA in lipids
• Lipase: enzyme that catalyzes the hydrolysis of fats

Phytic acid (inositol hexaphosphoric acid): o Present mainly in bran (whole grains and beans) o Problem to animal industry o Reduce the digestibility of starches, protein (cross-links protein & impede protease action), and fats o Makes soluble fiber, insoluble (cross-links) o About 70% of the phosphorus in cereals occurs as phytic acid o **Chelating agent: chelate divalent cations (calcium, zinc, iron, and magnesium) and thus these minerals become unavailable for absorption (anti-nutrient); can chelate toxins in colon as well o Sprouting/malting/germination of grains improves bioavailability of minerals such as phosphorus, iron, zinc, calcium, magnesium, etc. o Sprouting: practice of germinating seeds to be eaten raw or cooked. The reserve chemical constituents (protein/starch/lipids) are broken down by enzymes (protease/amylase/lipase/phytase) into simple compounds that are used to make new compounds; decrease in phytates and protease inhibitors o Phytate = phtyic acid bound to a mineral o Phytates perform an essential role in plants, as they are an energy source for the sprouting seed. When a seed sprouts, phytase enzymes break down the stored phytates o Phytase activity is beneficial; it converts phytic acid into inositol and phosphoric acid (this enhances protease hydrolysis) o Do not have enzyme that can digest phytic acid (ruminants excreted with fiber, not considered fiber) o Arabinoxylan: composed of two pentose sugars: arabinose + xylose
• Cross-linked by phytic acid
• Less soluble
• Arabinoxylan are one of the main components of SDF and IDF
• Impede * action (improves the quality of bread but is freq. inhibited by wheat.; improves bread volume and crumb structure by maximizing gluten performance and solubilizing polysaccharides in the wheat cell wall)

Ferulic acid esterified with arabinoxylan (AX); AX is less soluble. Impedes xylanase action on AX!! *Ferulic acid esterase or alkaline treatment can enhance xylanase hydrolysis. Phenolic acids = bound! So can reach hind gut with antioxidant activity; otherwise would’ve been secreted

**Vitamins commonly found in grains (usually in the bran, hence why whole grain consumption important):
1. Thiamin
2. Riboflavin
3. Niacin
4. Pantothenic acid
5. Pyridoxine
6. Phosphorus, potassium, calcium, magnesium, iron, copper, manganese

Vitamins commonly found in oilseeds:
1. Vitamin E

** Enzymes present in grains or sprouted grains & what they do:
I. Endo- and exo- type enzymes of amylases (hydrolyze starch)
II. Xylanase (hydrolyse pentosans; or AX)
III. Proteases (hydrolyze proteins/peptides)
IV. Lipase
V. Phytase (hydrolyze phytic acid)
VI. Lipoxygenase (catalyze peroxidation or polyunsaturated fats)

Grain Carbohydates
Major Starch/ Resistant starch Polymer of alpha glucose
Most utilized bio molecule in nature
In the endosperm? (larger in pulse/legume than cereal) Cellulose Cell wall component. Most abundant bio-molecule in nature, water Insoluble, polymer of beta-D glucose Hemi-cellulose (AX = DF) Polysaccharide cell wall component, water soluble and Insoluble fractions exist; but hydrate well! Extractable by dilute alkaline solutions (**AX: wheat grain/husk/bran, Galactomannan: guar/fenugreek/tara, Glucomanna: konjac)
AX: xylan + arabinofuranose, important in baking (function in sync with gluten protein to hold gas), usually exist in complex with phytochemicals, which influence their solubility!! Usually insoluble because of phytic acid and phenolics. *in wheat flour = improves water binding and loaf volume in baked goods, retards staling. Hydrolyzed to pentose sugars (xylose: a sugar OH used in diabetic jams)
AX can be bound to ferulic acid & phytic acid (phytase treatment can enhance xylanase hydrolysis) & diferulate (makes gibre become giant, ferulic acid esterase or alkaline treatment can enhance xylanase hydrolysis) Beta-glucan
Minor Galactomannan (Hemicell.) Branched: mannose backbone with galactose side groups (ratio differs with plant source and higher ratio e.g. locust bean gum 4:1 = highly viscous) Glucommannan Linear: hydrocolloid, glucose + mannose Pectin DF, cementing material in cell walls, gel strength/degree of esterification differ with plant source Inulin (fructan) SDF, prebiotic, very low aqueous viscosity, helpful in blood sugar management, leads to gas and bloating. Fructose polymer

Hydrocolloid: powerful water binding agents, absorbs water and becomes very thick. Grain components that are considered hydrocolloid:
• Galactomannan
• Glucomannan
• Beta-glucan
• Starch

STARCH
• Starch in grains embedded in a complex matrix therefore enzyme access is limited
• Pentosan is a hetero.
• Resistant starch acts like fibre
• Homo = one sugar
• High amylose/waxy/regular based on amylose content
• Waxy = softer, high amylopectin
• Amylose = linear, harder when congregates together
• Amylose-lipid complex are digested slowly; compounded together enzymes can’t get at it.
• Waxy = easier to access/digest, therefore higher GI
• Amylose alpha 1-4
• Amylopectin alpha 1-4, 1-6
• Legume content higher in starch generally than cereal

Stability = Consistency
Gel/Melting = Texture (pudding)

A Chain = do not carry any other chains
B Chain = carry one or more other chains
C Chain = original chain carrying the sole reducing end
Linear portions close together give crystalline structure, amylopectin responsible for formation of pebble like structure.

Amylose present in amorphous region

Bulk amorphous region is less packed (middle, one B chain extending)

On the outside, not crystalline (green), amylase can act here to penetrate inside [once inside, can find amorphous region]

The darker regions: close together form double helix coil, wrap around each other

Two forms of amylose: 1. Complex with lipid 2. Unbound
Lipid amylose complex makes bread softer. Bread needs fat to bake (softer, less chewy). Amylose molecules come out of the structure, leech out and binds with lipids (mainly monoglycerides). Amylose (hydrophilic) coils around hydrocarbon chain making amylose form a helical complex. Wheat 55% starch (gelatinizing, a lot of amylose, binds with fat if not with fat will get together when cooled, compact together, interaction with fat prevents from foaming compact structure therefore softer texture). Lipid complex is digested by our bodies. Native starch molecules – soluble in water because of many OH groups. Pepple granules insoluble because of compaction (crystalline) water cannot penetrate because so compact. To make it soluble – heat in water – gelatinization, disrupts packing, pull molecular apart.

GELATION : GELATINIZATION + RETREOGRADATION

Water swells the amorphous regions. Pulls crystals apart

Swelling → water entering → granular swelling → opens up structure → amylose leech out

Gelatinization = 3 steps**

Total/True amylose content – apparent amylose content = % amylose bound to lipids (iodine binding technique used)

Amylose – 24hrs re-association AA-AAP, amylose role in texture of bread.
Amylopectin – re-associate over 7 days, squeeze out water, water migrates to surface and evaporates, crust dries

Cook rice, open amylose and high glycemic index. In the fridge, forms associations, takes enzymes longer to break down

• Amorphous regions of starch are important for water to bond and act as a plasticizer during starch gelatinization. A plasticizer increases plasticity or fluidity of a material. Most starches gelatinize below 90C (in the presence of water) Amylolysis: enzyme hydrolysis of starch. Starch hydrolyzing enzymes: [specific enzymes related to end products]
1. Alpha amylase: 1-4alpha, D-glycosidic link → random attack/ endo enzyme
2. Beta amylase: 1-4alpha, D-glycosidic link → exo attack from non reducing end, releases maltose units
3. Glucoamylase/amyloglucosidase: 1-6 and 1-4alpha, D-glycosidic link → exo attack from the non reducing end; releases glucose units (less aggressive because must find exo)
.. iso-amylase, pullalanse,
Uses of amylolysis:
• Production of dextrins and syrups (combination of enzymes used to obtain syrups with various dextrose equivalents)
• Dextrin: used to manipulate texture of baked products – starch product, highly digestible, already chopped, hydrolyze much faster, higher GI

**Amylase preferentially hydrolyses the loosely packed regions [of native starch granules]

Corn syrup production through: STARCH LIQUIFACTION + SACCHARIFICATION
Liquifaction: starch gelatinized and dextrinized simultaneously; starch will swell and become viscous leading to technical difficulties in handling the slurry. Thermo-stable alpha-amylase will hydrolyze the amorphous regions of starch and block excessive swelling.
Saccharification: dextrins further hydrolyzed into sugars (note: yeast fermentable sugars from starch are glucose, maltose, and maltotriose);

Important functional properties of food starch (*know examples of first 3):
1. Thermal stability (CS)
2. Shear stability (CS)
3. Freeze thaw and gel stability (S)
4. Acid stability or resistance
5. Cold solubility

Why native starches are chemically modified – to improve their functional properties
A. Cross Linking: improve thermal, shear, and acid resistance (sodium trimetaphosphate, epichlorohydrin)
B. Substitution: improves freeze thaw and gel stability and cold water stability (acetic anhydride vinyl, acetate, ethylene oxide)
C. Double modification: cross-linking and substitution.

Resistant Starch: starch that is resistant to digestion in the human intestinal tract.
Classification based on starch physical state and macro structure.
RS1/Type 1: physically trapped inside other grain components (e.g. cells of endosperm of cereal, cotyledon of pulses, or other grain components such as protein). Present in minimally processed or coarsely ground groats, slowly digested but digested fully → not a fiber e.g. steel cut oats, kidney beans, cracked wheat, potato cubes, banana
RS2/Type 2: amylopectin crystals in starch granule (slowly digested) as well as amylopectin crystals in the retrograded starch! → not a fiber
R23/Type 3: amylose crystals in retrograded starch (insoluble & indigestible), amylose crystalline regions are so tightly packed, enzymes cannot access the glycosidic bonds, escape digestion (reach colon, get fermented), considered as insoluble dietary fiber → not a fiber
RS4/Type 4: chemically and enzymatically modified starches, e.g. isomaltose and isomalto oligosaccharides (soluble & indigestible), considered as soluble dietary fiber → soluble dietary fiber

Classification based on starch digestibility. Health benefits of RS: fermentable (only RS3, production of SCFA), cholesterol reduction, improve immunity/healthy colon, and prebiotic

Other low glycemic ingredients synthesized from glucose: polydextrose, isomaltose, isomaltooligosaccharides

PROTEIN
8 amino acids are generally regarded as essential for humans: phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, leucine, and lysine

Cysteine, tyrosine, histidine, and arginine are additionally required for infants and growing children

Arginine, cysteine, glycine, glutamine, histidine, proline, serine, and tyrosine are conditionally essential.

Functional groups in proteins: OH, COOH, NH2, SH, Alkyl groups

Major non covalent bonds in the protein structures:
- Hydrogen bond (OH/OH, OH/COOH)
- Ionic interaction (NH3/COO-)
- Hydrophobic interaction (between alkyl groups)
- Di-sulfide bond (SH/SH)

Cereal Protein Oilseed Protein
Low in lysine, tryptophan, methionine (lysine is high in oat/rye/GMO corn vs. other cereal) High in lysine
High in aspartic acid, glutamic acid, proline, alanine, leucine VERY high in aspartic acid, glutamic acid, and arginine High in serine, proline, glycine, alanine, and leucine Low in tryptophan

Protein hydrolysate:
Bioactive peptides: present in food and released from food proteins during digestion have a wide range of physiological effects in gut function, modulation of gut motility, stimulation of secretory processes, mineral binding, antibacterial properties, immunomodulation, antithrombotic activity, inhibition of ACE in the control of blood pressure, analgesic and other neuroactive effects. At least some significantly enhance the loss of protein from the SI causing an increased amount of protein to enter the colon. Or inhibit a.a. reabsorption or influence both processes simultaneously. *What is BP and give examples (Beta-casomorphin, bovine casein macropeptide, opiod agonists or antagonists)
Active peptide units that cause gluten intolerance, wheat allergy, and celiac disease remain encrypted within the gluten proteins of wheat, barley, rye, and triticale. Celiac patients can consume oat, rice, corn, sorghum, and buckwheat cereal grains providing they are not contaminated.

Osbourne Protein Classification (classified by solubility in solvents)
1. Albumin: water soluble, coagulated by heat, water soluble
2. Globulin: water insoluble, soluble in dilute salt (0.5M NaCl), salt water soluble
3. Prolamin: soluble in 70% ethyl alcohol
4. Glutelin: soluble in dilute acid (0.5M acetic acid or alkali)
Other proteins that do not fit into this classification
Electrophoresis (separated based on charge density)
DSC (melting temperature)
Sedimentation (sedimentation coefficient S values)
Gel chromatography (molecular sizing)
X-ray and NMR
*The ratio of the various protein groups is under genetic control and can be altered by breeding. E.g. High lysine corn is high in albumin, globulin, and glutelin but low in prolamine

Albumin/Globulin Prolamin/glutelin
Physiologically active proteins (enzymes) Storage proteins in cereals
Concentrated in the aleurone cells, bran, and germ Limited to endosperm
Relatively high in lycine, methionine, and tryptophan (regarded as high in food quality) Prolamin lack in nutritionally important amino acids such as lysine, tryptophan, methionine (low feed/food quality)

Glutenin: important for bread making, plastic properties. Alpha helix and beta sheets (2nd structure) both responsible for elasticity

With mixing: extension and reduction of intermolecular disulphide bonds (S-S reform in bread making)

Bakers yeast: Saccharomyces cerevisiae
- Compressed yeast (70% water, stored at T < 5C); more active strain
- Active dry/instant yeast (99% TG

Degumming: a process of removing phospholipids. The crude oil contains gum. They can get hydrated during the secondary processing of oils, settle in the tanks and be of inconvenience for further processing. Also phospholipids from soybean is high in ‘lecithin’ (phosphotidyl choline) which is an excellent emulsifying agent (*valuable byproduct)
Triglyceride derived from: # db Melting Point (C)
Linolenic 3x3 -24
Linoleic 3x2 -13
Oleic 3x1 5
Stearic 3x0 73

Partially hydrogenated: partially saturated and trans fat can be present

Fully hydrogenated: fully saturated and no trans fat

Trans & CLAs (both unsaturated)
Trans fat forms during partial hydrogenation of oils. CLA: isomer of linoleicacid (t9,c11 and t10/c12 are most abundant)

Trans – leads to CVD, naturally present in foods
CLAs – benefit heart health, it is a trans fat.

Inter-esterification: the process involves rearranging the fatty acids so they become distributed randomly among the triglyceride molecules. Catalysts are normally used to reduce the reaction temperature (sodium methoxide, 50-60C). The oil to be esterified must be extremely dry and low in free fatty acids and peroxides that reacts with the catalyst. Inter-esterification alters the physical properties of fat (melting point, solid fat index, and etc.). This process is used in the production of shortenings with specific solid fat index (SFI). Inter-esterified documents can then be separated by fractional distillation. Crystallization Behaviour of Fats: three types of fat crystals, α, β, β’
The β’ crystals have the capability of creaming and incorporation of air. The type of crystal formed is a function of the heterogeneity of the fatty acid composition. Apart from the fatty acid composition, TG composition is the important factor in crystallization behaviour. Fats that have a fairly homogenous fatty acid composition in their TG tend to crystallize in their beta form. More variety of fatty acids in the TG lead to more β’ crystals
Lard:
Native – Develop into hard β crystals
Inter-esterified – Develop into plastic (semi hard) β’ crystals

Cooking oil Heat stability, oxidative stability, melt rapidly near body temperature
Salad oil No solid fat at refrigerator temperature, good oxidative stability at room temperature
Margarine Water in oil, >80% fat (hydrogenated vegetable oil), emulsifier, salt, butter, flavor, color, Na-benzoate, vitamin A and D. Semisolid and spreadable, smooth texture, melt rapidly near body temperature, oxidative stability
Shortening Fat crystals to pick up and hold air, semisolid/hydrogenated/inter-esterified, incorporate into batter, smooth texture, provide lubrication on eating, oxidative stability, animal fats also used in the production
Mayonnaise Water in oil emulsion, 65% vegetable oil, 2.5% acetic acid or citric acid, egg yolk (act as emulsifier and provide color), salt, natural sweeteners, spices, various flavorings. Smooth texture, provide lubrication on eating, oxidative stability, oil is normally hydrogenated, winterized and interesterified
Extra Virgin Olive oil A free acidity, expressed as oleic acid, of not more than 0.8g per 100g (0.8%) and the other characteristics of which correspond to those fixed for this category in this standard
Virgin Olive Oil A free acidity, expressed as oleic acid, of not more than 2 grams per 100 grams (2.0%) and the other characteristics of which correspond to those fixed for this category in this standard
Pomace olive oil/regular Solvent extracted

MUSCLE
Three types of muscle:
1. Smooth
2. Skeletal (primary meat in N. America)
3. Cardiac

4 compositions of muscle: water, protein, fat, and connective tissue

**Myosin: Constitute the thick filaments of muscle, most abundant myofibrillar protein, assembles spontaneously, hydrolyzes ATP to ADP in presence of Mg, and binds to filamentous actin
- 6 subunits
- 2 globular heads are heavy chain myosin
- 1 alpha-helical tail
- ELC and RLC are light chain myosin
- HMM = Heavy meromyosin
- LMM = Light meromyosin
- Enzyme cleave coincide with hinge points
- Important contributor to texture, consider in processing
- Tail region drives formation of thick filament
- Globular heads bind to actin
- ELC = essential light chains, essential for binding to actin
- RLC = regulatory light chains, not essential for actin binding, phosphorylated

Thin Filament:
- second most abundant myofibrillar protein
- Major constituent of thin filaments
- Can exist as globular (G) or filamentous (F) form o In low salt, G form o In physiological salt, F form
- F-form a helix of actin molecules (will attempt to reassemble gives texture depending on salt)
- Tropomyosin: 2 stranded alpha-helical rod-like molecule
- Complex that traps myosin: o Tn1: Troponin 1 – binds to actin o TnC: Troponin C – binds to calcium ions o TnT = Troponin T – binds to tropomyosin

Sarcoplasmic Reticulum: transverse tubule opens to exterior of muscle cell (2 per sarcomere)
- Sequesters calcium ions until released by a nerve impulse
- Ryanodine receptor releases calcium
- Calcium-ATPase pump retrieves them

The myofibre:
- Is one muscle cell
- Surrounded by sarcolemma
- Polysaccharides
- Covered by basal lamina – thin collagen fibers of endomysium
- Multi-nucleated
- Cytoplasm = sarcoplasm
- Lots of mitochondria

Muscle fibre sarcolemma:
- Cell membrane
- Encompasses whole muscle fibre
- Is equivalent to cell wall
- Composed of phospholipid bi-layer
- Phospholipid: phosphatidyl likes water, 2 FA that don’t like water o Grass, low in saturated, floppy when cold, difficult to handle o Grain, high in saturated, stiff when cold, easier to handle

Connective tissue:
- Main protein: collagen (rope that holds everything together)
- Triple helix
- Contains hydroxyproline
- Fibrous or network protein
- Value parameter of meat (amount of connective tissue)
- Collagen quaternary structure: o Epimysium: around muscles o Perimysium (P): around muscle fibre bundles o Endomysium (E): around muscle fibres
- Collagen has no strength if not cross linked
- More issue in beef because longer amount of time to table
- Divalent: between 2 molecules; younger animals more tender because have more divalent
- Trivalent: between 3 molecules (as get older, goes from di to tri, heat resistant (doesn’t break down with cooking)
- Lysine residues involved in cross-links
- Divalent cross-links re-configure into trivalent
- Trivalent considered “mature” cross-links, divalent “immature”
- Two mature cross-links (trivalent); their [] linked to toughness o Pyridinoline o Ehrlich’s chromogen

The conversion of muscle to meat affects:
➢ Tenderness
➢ Meat appearance (colour, drip)
➢ Water-holding capacity
➢ Flavour
➢ Safety – microbial

How does muscle become meat?
1. Animal dies
2. Blood removed (no oxygen)
3. Death throes (no glucose, no oxygen)
4. Anaerobic glycolysis begins
5. Stored energy (glycogen) accessed

When is muscle meat? When rigor has resolved (rigor: stiffening and loss of extensibility), cross-linking of major muscle proteins, rigor occurs when muscle energy is gone.

Three stages of rigor:
1. Delay Phase: muscle tries to achieve homeostasis; uses glucose and other stores o Rigor delayed by energy saving pathways, muscle still extensible because ATP available o 2ADP → ATP + AMP (via Adenylate kinase) o ADP + creatine phosphate → ATP + creatinine (via creatine kinase)
2. Onset or Rapid Phase: (5 – 90 minutes) glycolysis most active principle use of ATP o Creatine phosphate exhausted o Muscle tries to maintain homeostasis o Anaerobic glycolysis source of energy
Glucose + 2Pi + 2ADP → 2 lactate + 2H+ + 2H2O

H2O: accumulation of water in cell to maintain osmality, releases water = drip from cut surface. How much drip depends on amount of ATP, lower the pH the more drip

Rate of anaerobic determined by 2 enzymes harvesting glucose from glycogen

3. Resolution Phase: proteolytic, enzymatic activity

Nutritive value of meat: determined by proteins, fat, carbohydrates, vitamins, and minerals. Specifically: Protein, B-vitamins, iron/minerals, essential fatty acids (which ones).

Lose fat and moisture when cooked. Lose more moisture, why fat percentage also increases.

Protein content increases with cooking. White chicken = low fat
Fish = less fat when cooked.
Processed meat products: enormously high in fat, protein and moisture are lower. Ash not assess because add sodium
Protein in meat:
- myofibrillar (myosin, actin)
- sarcoplasmic (enzymes, myoglobin) – leaks out, part of gravy
- connective (collagen, elastin) – turns to gel when cooked
- high quality o essential amino acids equivalent to dietary requirements o highly digestible o easily absorbed

Essential amino acids**:
• Phenylalanine
• Valine
• Tryptophan
• Threonine
• Methionine
• Leucine
• Isoleucine
• Lysine
• Histidine

Meat Quality and Acceptability
Colour: from myoglobin! globin (blue), heme group (red); Myoglobin concentration varies with animal age, species, muscle, and physical activity. Myoglobin takes 30-45 minutes to oxygenated and give meat a bright red colour referred to as bloom. Iron binding site exchanged for a water molecule; reversible?

Shelf-life of meat: 5-7 days max, meat lighting can increase meat temperature and hasten spoilage. Dark, firm, and dry meat: cattle that are stressed or exhausted, low glycogen produces beef with high pH (pH > 6.0)

Cooking and colour: denaturation of Heme, oxidation of iron, grey-brown, meat surface darker to dehydration and Maillard browning, if cooked under reducing atmospheres, denatured globin will be pink, ETC*: denatures O2 from myoglobin, can’t hold onto O2 long enough to make red therefore dark [make firm, dry, meat in O2 rich environment]

Water-holding capacity: the ability of meat to retain its water during the application of external forces such as cutting, heating, grinding, or pressing. It is important to the meat industry because it affects palatability, yield, and profit. Expressed as water retained in the meat rather than water expressed.
• Bound: hydrogen bound to protein
• Immobilized: dipolar attraction to protein and other water molecules
• Free: loose dipolar attraction to other water molecules
• Determined by: meat pH, protein structure, fat content, salt

Tenderness/ connective tissue content determined by:
1. Muscle function
2. Animal exercise
3. Animal age
4. Animal growth rate
.. measured by Warner-Bratzler Shear Force (force required to cut cooked meat across the muscle fibers). Sensory panel

Cold Shortening (shortening of sarcomere):
- low temperature of muscles before rigor completed
- chilled below 10C before 10 hours post mortem for bovine
- sudden release of Ca due to cold
- causes severe contraction of sarcomere
- toughness increases as sarcomere length decreases
Thaw rigor shortening:
- muscle frozen before rigor completed
- once thawed, calcium released
- muscle contracts because ATP still available
- can contract up to 80% of original length
- large amount of drip
- usually too tough to eat

Flavour: species flavour comes from fat, flavour carried by the water-soluble fraction, results from chemical reactions between fats, amino acids, and reactive sugars, inosine monophosphate and hypoxanthine associated with enhanced flavour
Ribose or other 5C sugars can be added, enhance umami

Sex effects and boar taint: apparent when pork cooked, unpleasant musky odour. Most prevalent in intact male pigs and mature sows, increases with age. Caused by fat-soluble pheromones, particularly androstenone, skatole, and indole, Can be suppressed by immunized with Improvest

Preserve meat (4): refrigerate (-1 to 4), freeze (-2), salting, processing

Processed meat: fresh meat that has had its properties modified by use of at least one procedure; to increase shelf life, maintain or improve flavour, and/or improve texture

Types of processing:
• Comminution (sausages)
• Curing
• Smoking (cured, seasoned, heat processed)
• Fermenting Advantage
Comminution (ground) - improved product uniformity
- increased tenderness Grinders, choppers, emulsion mill, and flaking machines. Meat and ingredients blended prior to further processing (allows for protein solubilization and better gel formation)
Ground meat releases water
Meat Emulsion Protein, fat, water, salt produces a fat in water emulsion.
1. Swelling of proteins and formation of viscous matrix
2. Emulsification of solubilized proteins, fats, and water this immobilizes water and prevents moisture loss, stabilizes fat
Curing Salt to inhibit spoilage, salt makes meat brown. Nitrite to stabilize colour, flavour and inhibit spoilage, sugar and seasoning for flavour, ascorbic acid as reducing agent, phosphates for water-holding (texture)
Increase Cl-, increased WHC
Smoking Meat exposed to wood smoke, formaldehyde major preservative, flavour and preservation
Antioxidants: phenols
Flavour: ketones, alcohols
Heat Processing Cooked until internal temperatures of 65-77C (52-54C for bacon) to kill microorganisms
Pasteurized but not sterile, emulsion gels set, entraps fat and sets structure, fixes and cures Nitrosylhemochromogen
Fermentation Microbial fermentation (LAB) of sugars and dehydration = special flavour and texture, low pH (4.6) denatures protein, prosciutto fermented and dried, beef jerky dried
Emulsions: A mixture of two immiscible liquids, one of which is dispersed in small droplets or globules in the other (in meat, dispersed phase is fat and continuous phase is water and solubilized proteins; solubilized myofibrillar proteins provide emulsion stability and coat fat droplets) **as fat droplet size decreases, the amount of soluble protein must increase because as fat droplet size decreases, the fat surface area increases.
- emulsion defects: fat capping in frankfurters, Globules of fat form because protein emulsion not stable, not enough soluble protein to cover the fat, fat coalesces, takes place during heating phase

Desirable product: Uniform appearance, composition, taste, physical properties from batch to batch Nitrosylhemochromogen: stabilizes Heme iron in myoglobin, prevents oxidation of fatty acids and rancidity. Nitrite toxic at 15 – 20 mg/kg body weight & carcinogenic. 15.7g/100g allowed in meat, Inhibit Clostridium botulinum

Alkaline phosphates: may not exceed 0.5% final product, phosphates improve WHC by improving solubilization of meat proteins by increasing pH, protect against browning and rancidity (antioxidant activity)
- mixed with comminuted meat, pickled (diffusion), injected and then tumbled, dry cure

Smoke density determines time of exposure, Frankfurters exposed to very dense smoke for short period, humidity important to maintain product moisture. Liquid smoke = condensation and fractional distillation of real wood smoke (advantage, no carcinogens)

Salts and phosphates used to solubilize meat proteins

Formed products: restructure meats (extruded or chunks in a gel, salts and phosphates used to solubilize meat proteins, heat gelation → patties, wieners, bolognas etc.) Patties mechanically formed and contact frozen, natural and synthetic casings, molds and casts used to stuff the casings, casings usually collagen or cellulose or plastic.

Meat used in processed products: skeletal muscle from high connective tissue cuts, trim or head meat. Dark, firm, and dry meat. Variety meats: heart, liver, spleen, tongue, ears, diaphragm, esophagus muscle
High binding – high pH meat desirable!
Low binding – low pH, high fat, high connective tissue meat. Connective tissue is good in raw products, poor in heat processed products. Collagen shrinks during heat processing so does not retain water, gelatinizes on cooking and does not stabilize fat.

MDM (mechanically deboned meat): tends to be partially emulsified, heme iron from marrow, oxygen from air, phosphates used to protect product from oxidation

Extenders and binders (non-meat);
- improve meat batter stability
- improve WHC
- enhance flavour/texture
- reduce shrinkage
- improve firmness for slicing
- reduce formulation costs Soybean / milk protein
Cereal flours
Starches from cereals or potatoes
Corn syrup and its derivatives
No more than 3.5% of final product
Soy no more than 2% of final product
Regulations:
• tightly regulated and monitored
• processed meats to contain less than 30% fat in cooked product
• moisture 45 – 60% (water added)
• No more than 0.5% phosphates