Lecture 9 Flashcards
Why has there been a decrease in ice cream consumption?
People being more health conscious
Replacing with frozen yogurt
What is the nutrition profile of Ice creams, frozen yogurt and other frozen desserts?
Protein
Calcium
Vitamin A
High fat and sugar content
What the difference between sorbet and sherbet?
Sorbet has no dairy
Sherbet has some dairy
-both low in fat but contain more sugar
What are the 3 main types of frozen dessert?
- Ice cream
- Sherbets
- Water ices
What are the 3 classifications of ice cream?
Super premium
-high fat 12% or more, high quality ingredients
Premium
-Lower fat than super
Standard/economy
-meets minimum requirements for ice creams, 10% or less
-economy slightly cheaters but same ingredients
What are other types of frozen desserts?
Dippin dots
-liquid nitrogen, store in very cold temps
Halo Top
- sugar alcohols don’t get absorbed so don’t contribute energy. Can cause GI issues
- Higher in protein
Mochi Ice Cream
-Outer shell made from gelatinous rice then ice cream in the middle
Is ice cream a colloidal structure?
Yes, they are an emulsion and they re a foam and air is incorporated.
Ice cream is a colloidal structure because characterized by dispersed particles that are intermediate in size and also large particles as well
Fat in 3D network contributes to mouth feel
What structure do frozen desserts have?
Foams with air cells dispersed in a continuers liquid phase
What kind of crystals are we aiming for in ice cream?
Small crystals which contribute to a smoother texture in the ice cream
How are fine crystals achieved?
Addition of fat and protein
Addition of sugar influences the freezing point thereby affecting crystal size
Mixing during freezing
Stabilizers including vegetable gums
Rapidly cooling forms small ice crystals
How does sugar influence freezing point?
Sugar lowers the freezing point.
If too much sugar is in the mix then the freezing is delayed because it will take the crystals longer to form which results in a larger crystal.
Too little sugar and the freezing point is higher and it cools too fast
how does mixing of ice cream during freezing impact crystal size?
Constantly being stirred helps to promote small crystal formation
What are common stabilizers and what do they do?
Locus bean gum is a hydrocoroline and they bind to lots of water to increase the viscosity and interfere with crystallization
What is overrun?
Amount of ice cream obtained above the amount of mix frozen
-based on the expansion of the ice cream when making it due to whipping air into the mixture
How much air is commercial ice cream vs home-made by volume?
Commercial is 40-50% air by volume
Homemade is 30-40% air by volume
Why is there a difference between store bought and homemade overrun?
Store bought has a higher over run because they are able to better control freezing condition to keep small crystals
-They get more frothy mouth feel
What happens when were is too much or too little overrun?
Too much: Foamy, airy product (frothy)
Too little: Heavy, compact, coats textured
How do we characterize the body of ice cream?
Firmness
Resistance to rapid melting
Homemade ice cream typically has less body (no added stabilizers)
How do we characterize texture of ice cream?
Fineness of particles
Smoothness
Lightness or porosity
-fat and stabilizers help promote smoother texture
What is homogenization?
The division of fat globules into small particles
What is the point of homogenization?
To prevent separation into a cream layer
What are the characteristics of homo milk because of its increased dispersion of fat?
Has richer flavour
Increased viscosity
Is whiter
-due to light being scattered more effectively with he number of fat molecules
What are some of the ingredients of ice cream?
Milk fat Non fat milk solids Sweeteners Eggs Stabilizers and emulsifiers Acids Fruit and fruit flavourings
What does milk fat contribute to ice cream?
Amount influences the viscosity and impacts incorporation of air
- moderate viscosity is desirable
- if too thick or thin air can’t be incorporated properly
What does nonfat milk solids contribute to ice cream?
Added to improve texture and flavour
-high % can reduce the free water content and improve the texture by allowing small crystals to form
What happens when there is grainy texture/ large crystals when using too much nonfat milk solids?
Lactose crystallization from milk solids at low holding temp. Lower % can lead to tiger over run and leads to poor body and fluffiness. 11% is the upper limit
-If the want to add more, they add lactase to breakdown the lactose to get a more desirable product
What are the ingredient modifications for light products?
- Fat modifications
- fats subs are usually protein, cats or lipid based
- fat contains a lot of flavour and can impact mouth feel - Sugar modificaitons
- bulking agents
- replacement sweetness results in off flavours - Nonfat milk solids
- increase to compensate for other ingredient changes
- too much can lead to gritty texture and have an increase in lactose content which leads to grittiness so you’d need to add lactase to break down the lactose
What are the steps to make hard ice cream?
- Blending of ingredients
- Pasteurization
- Homogenization
- hold overnight to improve texture palatability - Freezing, aging and hardening
Whats the difference between hard and soft ice cream?
Soft doesn’t undergo hardening process
-its continually being stirred
What is the salt to ice ratio when making home made ice cream?
Rocksalt and Ice
- 1:6 by weight (rock salt:ice)
- 1:12 by measure (rock Salt:ice)
Are eggs used in ice cream?
Yes
- make sure they are pasteurized eggs and milk
- if fresh eggs should cook mix to 74degrees C
What are still frozen desserts?
Prepared without agitation
- frozen in freezer
- and frozen with salt/ice mixture
- air beaten in before freezing with mixer
- Mix is relatively high in fat or other ingredients to control crystal formation
How do you store ice cream?
Fluctuating temps will promote:
- Grainy
- Icy
- Crystalline texture
Protect food from strong odour foods
What are the trends in milk consumption?
Agin population drinks less
Other options than just milk
Cultures might not consume milk (Canada is multicultural)
What is the nutritive value of milk?
Fluid Complete protein Calcium Vitamin D when fortified Riboflavin Other
How does osteoporosis occur?
When bones become thin, weak and porous
-they are more likely to break
What nutrient helps the absorption of Ca?
Vitamin D
where is the majority of the Ca found in the body?
In bones not blood
What is the composition of whole milk?
Water 88% Protein 3.3% Fat 3.3% Carbohydrates 4.7% Minerals 0.7%
What kind of proteins area in milk?
Casein 2.8%
Whey protein 0.6%
What is the composition of milk solids in milk?
Protein 3.4%
Lactose 4.8%
Minerals 0.,7%
what is casein?
A Phosphoprotein
80% of milk protein
What makes casein precipitate?
Precipitates to form curds if:
- acid is added
- Rennet added
- Age gelation occurs
What is age gelatine?
Gelation of ultra high temperature milk
-is the result of irreversible micelle aggregation
What is whey?
Lactalbumin and lactoglobulin
- makes up 20% of the protein in milk
- byproduct of making cheese
how does whey coagulate?
By heat
which kind of whey is used for cheese vs. yogurt?
Acid whey used for yogurt
Sweet whey used for cheese
Which milk protein is more water soluble?
Whey more water soluble than casein
What is fat in milk called?
Milkfat
Butter fat
cream
Is milk an emulsion?
Yes
-milk fat droplets are dispersed in the milk
what is milk fat composed of?
Triglycerides (primary type)
Phospholipids
Sterols -cholesterol
Way is the carbohydrate in milk?
Lactose (disaccharide)
- can produce glucose and galactose when hydrolyzed
- least sweet of the sugars
What does it mean to have a lactose intolerance?
Role of enzyme called lactase to break down the lactose, if you don’t have enough of the enzyme can go through your GI and bacteria can ferment and cause gas and discomfort
what is the order of greatest lactose content to least?
Milk Goat milk Buttermilk Yogurt Ice cream Cottage cheese Hard cheese
What is the nutrient profile of milk?
Ca, P, Mg, K, Na
Vitamin ADEK (fat soluble)
Fortified with Vitamin D
Thiamin, Riboflavin, Niacin, B12 (Water soluble)
Why is vitamin A added to low fat milk?
Because it is removed with the cream when you get a reduced fat milk product
What are the enzymes associated with milk?
- Lipoprotein lipase (LPL)
- Plasmin
- Alkaline phosphatase (ALP)
What is LPL?
Associated with casein micelles
What is Plasmin?
Proteolytic enzyme that splits proteins
Heat stable and responsible for bitter flavour in pasteurized milk
What is Alslkine phosphatase?
Found in all raw milk
More heat stable then pathogens therefore pasturization destroys pathogens and then enzyme
-we look for this enzyme to see if the product has bee properly pasturized
Why does milk get its white colour?
Colloidally dispersed casein micelles
Ca phosphate salts
What other colours can milk be?
Yellow: Carotenes
-depends on breed of cow and feed
Green/yellow: fluorescent colour in liquid whey
-Denaturation of riboflavin (why we switched from glass to cartons)
Does pasteurization impact flavour?
Minimal impact
Tends to disappear during storage
What gives milk an off flavour?
Feed Bacteria Chemical Changes Absorption or foreign flavours Light exposure Poor ventilation in milking parlours
What is the acidity of milk and how does it affect milk?
pH is 6.6
Acidity decreases on standing with loss of CO2
Acidity increases by action of lactic acid producing bacteria
what is the theory of milk and acne?
Diets high in fat calories meat high GI foods and dairy might contribute towards acne
-not enough evidence to make specific recommendations to treat of prevent acne
What are the types of milk?
whole 3.5% milk fat 2% 1% Skim Flavoured Concentrated fluid milk Dry milk
Why is fair life milk different?
Has more protein because it is a whey protein concentrate
- has less sugar
- lactose free
What are the 2 kinds of concentrated fluid milk?
Evaporated
-60% of the water found in regular milk has been removed
Sweetened Condensed
- 15% sugar added
- concentrated to 1/3 former volume
What is the difference between. Evaporated and. sweetens condensed milk?
Evaporated is sterilized and sweetened condensed is not because of the high sugar content acts as an antimicrobial
What is dry milk?
Whole or low fat dry milk (short shelf life)
Dried buttermilk
How is yogurt made?
From all types of pasteurized milk before adding the cultures
what is the difference between Probioticm greek and skier yogurt?
Probiotic: Have strains that survive the GI
Greek: is strained to feet rid of extra whey, contains more protein
Skier: Highest protein (Icelandic)
What are the types of milk products?
Yogurt Buttermilk Acidophilus milk Kefir Filled milk Imitation Milk
What is butter milk?
Low fat cultured milk
Liquid remaining after cream is churned to producer butter
What is acidophilus milk?
Low fat/skim milk and cultured with lactobascillus
What is kefir?
Sheep, cow or goat milk
Fermentation form grain producing yeasts
-more acidic in flavour
What is filled milk?
Substitute milk produced from (doesn’t meet standards to be considered milk):
- nonfat milk such soy bean oil combined with water
- non fat milk solids
- Emulsifier, colour, flavouring
What is imitation milk?
Usually contains no milk
May contain casein, whey
Ingredients: water, corn syrup, sugar, vegetable fats, protein source
What are. the types of cream products?
Fluid cream:
- Heavy 36%
- Light cream or coffee cream 18-30%
- Light whipping cream 30-36%
- Half and Half 10.5 to 18%
Sour cream
What is sour cream?
Use a culture of lactobacillus lactic organisms
Acidified source cream when manufacturers use food grade acid instead of bacteria
Thickness is relative to the amount of fat in the sour cream
what is dried cream?
May be reconstituted to liquid form
What are some of the nondairy products?
Whipped topping: more stable than dairy products and maintain quart during storage for a long period of time
Coffee whiteners: Non dairy because main product isn’t dairy or cream
May contain casein or whey
How does heat in food production affect milk?
Proteins coagulate
-whey proteins coagulate and car form in the bottom of the pan
Calcium is less dispersed
-Ca is decreased by heating and a small part is precipitated out
Fat globules coalesce
-Forming more of a solid, and clump together
Surface films may form
-Can be coagulated proteins precipitated salt and some of the fat as well
Sugars and protein may brown
-maillard reaction
what are the 4 ways to coagulate milk?
- Acid
- casein is highly susceptible - Enzyme
- Rennet (cheese making)
- 40-42C optimal temp - Phenolic compounds
- Found in fruit and veggies (stems, roots, pods, seeds)
- organic acids - Salts
- Salts in milk
- Sodium chloride
How is curdling in cooking?
Tiger fat milk is more stable than low fat milk
Non fat dry milk has limited stability
Fresh milk is less likely to curdle than older milk
What is freezing like with milk?
Protein film is weakened
Fat globules coalesce (come together)
Dispersion of protein and calcium phosphate affected
-if frozen t lower rate, film of protein that acts as an emulsifying agent is weekend/ruptured
What do we need to be aware of when whipping cream?
Temp and viscosity (cold whips better) Fat content (30%min) Amount Whipped Sugar increased time to whip Sugar decreases volume and stiffness Acidity has no effect
What is the science behind whipping cream?
Whipping cream has a foam that occurs when whipping cream
Need a surfactant to lower surface tension between gas and liquid. Normally the protein in the milk
Don’t whip for too longer you’ll get butter
How do you care for milk?
Cleanliness
Cold temperature
Prevention of contamination
Protect from light exposure
What is the nutritive value of cheese?
Most high in:
- Protein
- Fat
- Calcium and phosphorus
- Vitamin A
- Sodium
what are the 4 main ingredients of cheese?
Milk
Cultures
Rennet (rennin) - clotting enzyme, synthesized from fungus or bacteria
Salt
What is the natural colour of cheese?
White
-annatto natural yellow colouring from a seed
What are the characteristics to classify cheese?
Ripened- aged
Unripened- consumed right after processing such as cottage cheese
Natural- Made directly from milk
Processed- uses natal cheese and other ingredients to change texture/melting point
How do you group cheeses?
- Amount of moisture in the finished cheese
- soft
- semi hard
- hard - Kind and extent of ripening
- unripened
- mold ripened
- bacteria ripened
What do we need to consider to make cheese?
Optimal moisture pH Fat Protein Ratio Texture Aroma Flavour Taste
What are the steps to making cheese?
- Promoting curd formation with acid produced by lactic acid bacteria
- Cutting the curd into small pieces to allow whey to escape
- Heating the curd rot contract the curd particles and hasten expulsion of whey
- Draining, knitting/stretching, salting and pressing curd
- Curing or ripening
