Question

What is the difference between sweet cream butter, cultured butter, clarified butter, and margarine?

Describe how ice crystals, concentrated cream, and air all contribute to the final structure of ice cream.

Answer 1

Butter is made by churning cream that is initially obtained by passing the whole milk through a centrifuge that separates butter fat in milk from non fat milk part.

The cream thus obtained can be churned in a butter churner to get butter; this is sweet cream butter.

Sweet Cream Butter

The butter we all know and love is of the sweet cream variety. Sweet cream butter is made from butter that is fresh and sweet tasting, rather than aged and tart. The end result is butter with a light, uncomplicated flavor that is well-suited for table use or baking.

cultured butter

Alternately, if some lactic acid bacterial cultures ( like Lactococcus lactis, Leuconostoc species) are added and the cream is incubated for these bacteria to grow to produce acid ( lactic acid) and flavor compounds ( diacetyl) and then the cultured cream is churned to obtain butter, it is called cultured butter

The addition of the cultures does several things:
Causes the butter to taste slightly tangier, due to additional lactic acid
Results in a higher-fat product, which in turns makes the butter more silky and gives it a richer taste
The cultures also aid in digestion
And the additional acidity also makes for better baked goods, giving you a "more tender crumb or crust"

Margarine
Margarine is made by emulsifying vegetable oil with skimmed milk or by hydrogenating vegetable oils. It may be a plant product or a combination of plant and dairy product.Margarine contains mostly vegetable oil; High levels of unsaturated fat and trans fat.Margarine varies largely in taste, depending on brand, but rarely if ever has the full taste of butter

Clarified butter

Clarified butter is milk fat rendered from butter to separate the milk solids and water from the butterfat. Typically, it is produced by melting butter and allowing the components to separate by density. The water evaporates, some solids float to the surface and are skimmed off, and the remainder of the milk solids sink to the bottom and are left behind when the butter fat (which would then be on top) is poured off. This butter fat is the clarified butter.

part b

ice cream

Ice cream is a type of emulsion, a combination of fat and water that usually wouldn’t mix together without separating. However, in an emulsion, the very small droplets of fat are dispersed through the water, avoiding this separation. The manner in which this is accomplished is a result of the chemical properties of molecules in the emulsion.

What is ice cream?​
Ice cream is an very complex and delicate substance that contains all three states of matter at once:

1 solid (ice and fat)
2 liquid (sugar solution)
3 gas (air bubbles).

Component #1: Ice
Ice crystals give ice cream it’s firmness. They give it body and solidity. That resistance to your spoon and your tongue: that comes from ice crystals. About 30% of ice cream is made up of ice crystals.

Ice crystals are formed from the water in the mixture as it freezes. Maybe you think there's no water in ice cream? We don’t usually add any directly. But don’t forget: milk and cream are mostly water. Milk is 90% water. And cream is around 60% water.
The size of these ice crystals is very, very important! Small ice crystals will make the ice cream smooth and less cold in the mouth. While large ice crystals will give the ice cream a coarse texture and an icy mouth-feel.

(This apparent difference in temperature is because larger ice crystals require more heat to melt. Since this takes heat away from your mouth, it makes the ice cream seem colder.)

Different people like different types of ice cream but one thing's for sure: good ice cream should be smooth! So keeping those ice crystals small is one of the most important parts of making quality ice cream.

Component #2: Air
Air gives ice cream it’s softness. It keeps the ice cream pliable and makes it easy to scoop.

The air also contributes greatly to texture and consistency. Ice creams with more air are lighter, fluffier and less "creamy". While ice creams with less air are heavier, denser and more "creamy".Air bubbles are added to the ice cream by the paddle (also known as the dasher) that churns the mixture as it freezes. The faster the blades of the dasher move through the mixture, the more air they add. And different shaped dashers will also affect how much air is pushed into the mix.
Component #3: Fat​
Fat contributes to ice cream in four important ways:

it helps to stabilize the final structure by trapping air bubbles
it thickens the mixture which slows melting
it delivers flavor
it gives that lovely creamy texture and mouth-feel.
The fat in ice cream mostly comes from the milk and cream and is called butterfat. Around 3.4% of whole milk is fat. While cream can vary between 30 and 48% fat, depending on what type is being used. So mostly it comes from the cream!

How fat helps stabilize the ice cream
Well, before the mixture is churned the fat globules are very small and are kept apart from each other (more on this later). However, while the ice cream mixture is being churned, the fat globules bang together and join up to form long, pearl like strings that wrap around the air bubbles.These strings hold the air bubbles in place, keeping the “foam” stable. This is how the ice cream maintains it’s light texture, soft consistency and volume: all the qualities that the air bubbles contribute to ice cream.

How fat effects creaminess and flavor release
The fats also give ice cream it’s creamy texture and richness. Higher fat ice creams are rich and creamy with a long lingering after taste. While lower fat ice creams have a much lighter, cleaner flavor with a short lived after taste.

Interestingly, any additional flavours (fruits, chocolates, nuts etc) in the ice cream are also affected by this. This is because the fat tends to hang onto these flavours.

So the fruit flavor in a strawberry ice cream will be delivered more slowly and subtly (but more long lastingly) in a higher fat ice cream. And will be more clearer and prominent (but relatively short lived) in a lower fat ice cream.

Whether you prefer higher fat, rich and creamy ice creams or light and clean, lower fat ice creams is a matter of personal taste. American and French ice creams tend to be higher in fat. While Italian ice creams are usually a bit leaner.

Component #4: Sugar Solution​
This is the liquid part of ice cream. It’s in this sugar solution (also called the matrix) that the solid ice crystals and fat globules and the gaseous air bubbles are suspended.