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Food Technology and Engineering

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Chinmayee Rindani

on 3 March 2014

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Transcript of Food Technology and Engineering

CN4215R - Food Technology and Engineering
FROZEN DESSERTS
Investigation of Ice Cream, Gelato, Frozen Yogurt & Sorbet
What's the difference?
Introduction
Structure of Ice Cream
What is ice cream??
Differences in Rheology
Chemical Composition of Frozen Desserts
Importance of Sugar
Other Considerations of Frozen Desserts
Flavours
– aroma and taste component
-fat or water soluble

Colours
-customer perception
-reasons for addition:
add/change, enhance,
or make uniform

Other Components
-chocolate
-fruit
-syrups
-bakery products

Comparison Summary
Milk, eggs, sugar, additives blended for 6-8 minutes

Homogenizing

break the fat particles down into many small droplets (1micron diameter)
hot mix is forced through a small valve under high pressure (up to 150 atm).
Pasteurization
Temperature: 80.5 Degrees
Holding time: 31s in the Pasteurization Tube
Innovative Ideas
Summary
Examine 4 frozen desserts
Ice Cream, Gelato, Frozen Yogurt & Sorbets
Discuss and compare
Rheology, Chemical and Nutritional Composition, Manufacturing & Innovative Ideas
A micro structure of…
Viscous matrix of sugars, polysaccharides and milk proteins
Mix is cooled and held at between 0 and 4 °C

Two important processes to stabilize air bubbles later:
Emulsifiers adsorb to the surface of the fat droplets, replacing some of the milk protein.
Fat inside the droplets begins to crystallize.

Aging Time
> 6hours for extruded products
2 hours for most products
Freezing
Creates ice-crystals, air bubbles and the matrix by simultaneously
Aerating
Freezing
Beating (shear stress)

5 atm pressure inside barrel
Barrel wall temperature -30°C
Residence time 30-60s

Higher Shear
Increases the amount of partially coalesced fat and makes the ice cream stiffer
Smaller the air bubbles
Larger crystals

Slow down coarsening

Cold air (- 30 °C to - 45 °C) blown over ice cream

Low temperature and fast air flow increase rate of heat removal

Hardening
Sorbet
Similar process
Do not contain fat, so do not need aging
Have aeration
Barrel pressure of 2-3 atm is used to achieve the required overrun
On exit from the factory freezer, a water ice slush is produced, with an ice phase volume that is determined by the outlet temperature.

Frozen Yogurt
Additional
fermentation step

Minimal aeration
Lower stirring

Gelato
Chemical composition
Desserts for diabetics
Desserts for those suffering from Lactose intolerance
Desserts for the Health Conscious




No sugar added - Use of substitutes
Natural sweeteners-  Xylitol, found in corn, berries and mushrooms
Artificial sweeteners such as Sucralose (Splenda)
Purpose:
1. To retain the same “sweetness” level: Xylitol's sweetening power is the same as that of sucrose (table sugar)
2. To avoid compromising health: The body does not require insulin to metabolize xylitol.
Artificial sweeteners do not affect blood sugar levels. They cannot be broken down by the body and pass through our systems without being digested 

Frozen Desserts for Diabetics
Concerns:
Safety
Natural sweeteners are safe for consumption but artificial sweeteners need to be approved as they may have side effects
Example: ADI for Sucralose is 5 milligrams per kilogram, or the equivalent of 6 cans of diet pop

Taste
“It is quite simply a delicious, creamy vanilla ice cream. It isn't too sweet and to be honest you would be hard pressed to distinguish this from any good quality creamy vanilla ice cream."

Frozen Desserts for Diabetics
Lactose intolerance means the body cannot easily digest lactose, a type of natural sugar found in milk and dairy products.

Lactose free products- non dairy
Two methods to allow consumption of frozen desserts for those who are lactose intolerant
1. Use of dairy free products- substitutes
2. Treatment before production.


Frozen desserts for Lactose Intolerance
Low calories desserts - replacing cream and eggs with a milk substitute

Use of sugar-free products
- Sweeteners such as monk-fruit

Reducing the fat percentage
- Reduced, Light, "Low fat" Frozen Dairy
Dessert



Frozen Desserts for the Health Conscious
Chemical and
Nutritional Composition

Frozen desserts is a growing industry
Recorded sales worth $25.1 billion in 2011
Constant progression and new innovations to meet the changing market

Sensory Properties
Blending
Aging
Manufacturing and Processing
Differences in Processing
Ingredients serve as purpose in:
the manufacturing process
stabilizing agents
enhance flavours and textures


Primary Ingredients in Frozen Desserts
percentage of water frozen
Water (40-65%)
- dissolving medium for rest of ingredients
-forms ice crystals

Sugar (10-65%)
- lowers freezing point of water
-sweetener and texture enhancer

Milk Fat (1-20%)
- assists in aeration of product
-adds density,smoothness and flavour

Air-
contributes to consistency, texture and volume







Additional Components
Stabilizers
-add viscosity, control ice crystallization
E.g. Non-fat Milk Solids

- protein source (surface active)

Emulsifiers
impede water-fat seperation
decrease surface tension
E.g. Lecithin (egg yolk)
mono/di glycerides
Food Taste & Rheology
Full transcript