Course:FNH200/2011w Team14 IceCream
Ice Cream Introduction
What is ice cream and how is it made? We are going to compare the function of ingredients in hard and soft ice cream and their subsequent roles during manufacturing. Ice cream, as defined by the Canadian Standards for Ice Cream:
(a) shall be the unfrozen, pasteurized combination of cream, milk or other milk products, sweetened with sugar, liquid sugar, invert sugar, honey, dextrose, glucose, corn syrup, corn syrup solids or any combination of such sweeteners;
(b) may contain
- a flavouring preparation,
- cocoa or chocolate syrup,
- a food colour,
- pH adjusting agents,
- microcrystalline cellulose or a stabilizing agent or both in an amount that will not exceed 0.5 percent of the ice cream made from the mix,
- a sequestering agent,
- not more than one per cent added edible casein or edible caseinates; and
- propylene glycol mono fatty acid esters in an amount that will not exceed 0.35 per cent of the ice cream made from the mix and sorbitan tristearate in an amount that will not exceed 0.035 per cent of the ice cream made from the mix; and
(c) shall contain not less than
- 36 per cent solids, and
- 10 per cent milk fat or, where cocoa or chocolate syrup has been added, eight per cent milk fat.
The Milk fat is what makes ice cream rich and creamy! Ice cream is composed of emulsions - mainly of milk or cream. Emulsion products are tricky to store for long periods of time because emulsions have the tendency to separate if left standing for too long. Creaming is a phenomenon in which the dispersed particles suspended in an emulsion rise to the surface of the continuous phase and settle in a layer on top. This separation of phases is what ice cream producers are trying to avoid, and a variety of food additives are what prevent it.
The history of ice cream is widely unknown however there are a few folklore stories that propose the origin. It's said that ice cream first made its appearance by the Emperor Nero of Rome, 54-68 AD. He sent his slaves to the mountains to bring him back snow, so that he could combine it with nectar, fruit pulp, wine or honey to create a primitive form of ice cream or "sweet snow". Another version of the origin of ice cream is said to be a legend and all started with the Italian explorer Marco Polo. He reported seeing "milk dried into a kind of past"  after spending 17 years in China. This developed into a story of Marco Polo bringing home the recipe for ice cream from China.
The following outlines major events in ice cream's history in North America.
- In 1776, the first ice cream parlor opened in New York City.
- In 1812, ice cream was served in the White House by Dolly Madison at the second inaugural ball.
- In the 1850's the first ice cream factory opened by Jacob Fussell.
- In the 1930's Soft ice cream was originally created by J.F. McCullough, the founder of Dairy Queen, and Tom Carvel, the founder of Carvel chain of parlours. The air content pumped into cream can reach 60%! 
- Chapman's Ice Creamis Canada's largest independent Ice Cream manufacturer and has been making hard Ice Cream since 1973. All Chapman's products that contain milk are made with 100% Canadian milk.
This video shows an old technique for ice cream making that prevents air from getting into the cream resulting in a dense and thick desert, it is called the French Pot Method.
Comparing the ingredients in Mcdonalds soft serve vanilla ice cream and Chapaman's vanilla ice cream  it is apparent that the quantity of ingredients and the presence of a variety of additives are different. While the basic ingredients remain the same, the discrepancies allow for two very unique products in regards to their texture and tastes.
|Soft Ice Cream||Hard Ice Cream|
|Modified Milk Ingredients||Cream|
|Sugar||Modified Milk Ingredients|
|Soy Mono and Diglycerides||Glucose|
|Guar Gum||Mono and Diglycerides|
|Dextrose||Locust Bean Gum|
|Artificial Flavor||Cellulose Gum|
|Natural and Artificial Flavors|
Ice Cream Additives are:
- Mono and diglycerides are used as emulsifiers to help mix the ingredients together. They are hydrogenated oils extracted from palm seeds, rapeseeds and soya beans. In ice cream, mono and diglycerides are used to destabilize the emulsion in the cream or milk which creates a more stable structure. They allow easy blending of non-interacting molecules such as water and oil or fat. They also help keep ice cream from drying out and help the ice cream separate from packaging surfaces during or after manufacturing.
- Guar gum is used as a gelling agent to thicken and stabilize the ice cream. It is a water soluble polysaccharide that is used in food production for its water thickening capabilities. Guar gum is known to have approximately eight times the water thickening capabilities than cornstarch, therefore only small quantities are used in ice cream production to achieve the desired viscosity. Guar gum is also useful as an emulsifier and stabilizer in the production of ice cream. As an emulsifier it impedes the fat droplets in the milk or cream from coalescing, and as a stabilizer it prevents the solid particles in the milk, sugar, and flavorings, from settling on the bottom of the container.
- Carrageenan is a gelling agent used to thicken and stabilize ice cream. It is a flexible polysaccharide that is isolated from red seaweed. The large molecules twist around into helical structures. Carrageenan is a popular food additive in food production because of its gelling abilities and also because it may be used as a vegan substitute for gelatin. There are a few different forms of carrageenan that react with specific molecules and therefore serve particular functions in food processing. The Kappa variety is most often used as a thickening agent in ice cream production because it increases viscosity. The challenge facing the use of carrageenan as a thickening agent in ice cream is that all the varieties of carrageenan are soluble in hot water, but only the lambda variety is soluble in cold water.
- Cellulose gum is a thickening agent which increases the product's viscosity without changing other properties of the ice cream. It is used in a wide range of foods as a viscosity modifier. In ice cream, cellulose gum acts to stabilize emulsions by preventing the separation of the dispersed particles, such as fat and protein solids, from the continuous water phase of milk and cream. Cellulose gum is extracted from the cell walls of plant cells and contributes to the creamy, smooth texture of ice cream.
- Locust bean gum (only in hard ice cream) is a viscosity modifier and texturizer extracted from carob tree seeds. The seeds are dried into a pale yellow powder that is added to food products to increase viscosity. Its use is popular in ice cream manufacture because of its pleasant, sweet, natural taste. In addition to that, locust bean gum also promotes ice crystal growth and decreases the syneresis of water in the ice cream when used in combination with carrageenan. The promotion of ice crystal growth may be why locust bean gum is used in hard ice creams only. More ice crystals will increase the solidity of the ice cream. Locust bean gum, like carrageenan, is also only soluble in hot water.
- Dextrose (only in soft ice cream) serves as a sweetening agent.
Locust bean gum, cellulose gum, guar gum and carrageenan are all thicking or gelling agents that are used to adjust the consistency of ice cream and stabilize the ingredients in one solid form. Their stabilizing qualities help to prevent ingredients from separating out.
The more emulsifiers you add to ice cream leads to an increase in fat destabilization resulting in a decrease in melting rate and better shape retention during melting. Although our products do not contain polysorbate-80, it is best to combine this with monoglycerides to allow this interaction to occur more readily. Examples of such emulsifiers are polysorbate-80, and mono and diglycerides.
Additives are not the only ingredients important in ice cream making:
- Cream and modified milk ingredients are what make ice cream, ice cream.
- Sugar, glucose, dextrose, natural and artificial flavors add sweetness and flavor to the ice cream. They also help promote desirable chemcial reactions in the ice cream.
- Sugar, glucose and Dextrose are used as sweeteners in ice cream. They not only add to sweetness to the product but decreases the freezing point so it doesn't freeze solid at low temperatures. 
How It's Made
Ice Cream Production:
- Using different quantities of the above listed ingredients, different recipes for ice cream can be formulated. The additives contribute to the textural components and to the overall consistency and shape of the product. Without them the ingredients would not hold together or remain consistent and then could not be stabilized into a solid form.
- The staple ingredients of both soft and hard ice cream are milk ingredients, sugar, glucose, and flavouring (vanilla, chocolate, etc). Different quantities of these ingredients will result in a different end product allowing for a wide variety of ice creams.
- Once the desired recipe is set, the ingredients are weighed and blended together to ensure consistency. The dry ingredients are blended into the wet ingredients through rigorous mixing.
In order to destroy pathogens and limit the presence of spoilage causing bacteria, the ice cream mix is pasteurized at a control point determined for ice cream: 69 degrees for 30 minutes; 80 degrees for 25 seconds. The most common methods are batch pasteurizers and continuous methods (high temperature short time pasteurization).
This method denatures the whey protein in milk ingredients. The ingredients are blended while being heated with either steam or hot water in the vats. The product is heated to 69 degrees, and is kept at this temperature for at least 30 minutes to ensure that the product meets the pasteurization requirements in order to destroy the pathogenic bacteria. The product is then homogenized using high pressures, and cooled to refrigeration temperature along a heat exchanger.
HTST Continuous Method:
This involves three sections: heating, cooling, and regeneration.
Using a two stage homogenization technique, the ice cream mix is homogenized to form a fat emulsion. Homogenization has many purposes in creating the ideal ice cream texture but is mostly concerned with reducing the size of fat molecule giving the ice cream a smoother, richer, and melt-resistant texture. The same temperature for pasteurization is used for homogenization to reduce clumping.
Pressure is also controlled during homogenization; pressure was determined by the composition of the fat in the ice cream mix (lower pressure is used for more fat molecules; and higher pressure for less fat molecules). A two stage homogenization method requires that the pressure is higher during the first stage then the second.
To ensure that the fat has time to crystallize, and the proteins to hydrate (increases viscosity), the mix is aged for 4-24 hours. This is solely for textural properties.
Freezing and Hardening:
This is the stage when the colouring and/or flavouring is added to create the different flavours of ice cream. The water component of the mix is frozen during this stage while simultaneously whipping air into the frozen mix using the 'Continuous Ice Cream Barrel Freezer.
Because of this stage, up to half of the final ice cream product is air making the product light, whipped and fluffy.
This "semi-frozen slurry" is termed Soft Ice Cream. At this stage hard products are added, like nuts or fruit. The only difference between the production of soft ice cream and hard ice cream is that the hard ice cream continues on to the next and final stage, whereas the soft ice cream is put into cones and consumed.
Blast freezing at -30 to -40 degrees Celsius is what changes soft ice cream to hard. The water, which was half the volume at the beginning of the previous stage, is now frozen during the hardening phase. Hardening requires plate freezers or freezing tunnels at a rapid low temperature. Temperature accuracy is imperative to this stage because above -25 degrees, the ice cream is a risks of forming ice crystals.
Here is a fun video showing the manufacturing of ice cream!
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