There are three main differences between the two:
I. Shape
The shapes of natural cheese are very rich, such as block, flake, cube and broken block. In the order shown in the figure.
There are also cylindrical, fan-shaped and so on
Processed cheese is much less in shape, usually sliced, put in metal cans, cartons, plastic bottles or pipes, and can be squeezed out like salad dressing:
From the shape, processed cheese and natural cheese are both flaky, so it is difficult to distinguish them. Processed cheese is generally soft and has a low melting point, while natural cheese, if it can be cut with a knife (usually cut from block cheese with a knife), is hard in texture, and it is still possible to distinguish it by looking and touching.
Second, composition
Natural cheese: The raw material for making natural cheese is milk or goat milk. By adding acid or chymosin, protein in milk is concentrated into small pieces and precipitated, which is separated from whey. Then squeeze out the excess water to form a larger cheese block. Finally, salt, pigment and microorganism are added to give cheese special flavor, texture and color through fermentation, and then give it special shape through mechanical processing.
Main ingredients: water: 30. 17%, fat: 34.39%, protein: 3 1.23%, minerals: 4.3 1%.
From these data, we only need to know two things:
1, the ingredients of different kinds of cheese will change, but protein and fat are always the most important ingredients.
2. Cheese contains oil and water (the ratio is close to 1: 1). Oil and water are incompatible, so it needs to be fully emulsified, so that the cheese will not be layered when placed.
Protein in cheese is a natural macromolecular emulsifier, which makes cheese into a colloid with uniform emulsification. But under the condition of heating, natural cheese is still easy to produce oil.
Processed cheese: The FDA of the United States stipulates that at least 565,438+0% of the raw materials for processed cheese are natural cheese, and less than 49% of the remaining ingredients include additives, water and other milk raw materials, such as milk powder, anhydrous milk fat and whey solids. The additive content of processed cheese is indeed higher than that of natural cheese, and it is purposeful to add additional additives.
PS。 The original answer is "5 1% processed cheese is made of natural cheese and 49% is additive". This description is incorrect. Thanks to @ Liang Hai for pointing out the mistake, which was corrected by the author on August 30th, 20 13.
Target 1: Improve the function.
How to make processed cheese? First, take a small pot, put the cut natural cheese pieces in it and heat it until it melts. At the same time, some emulsifying salts (such as sodium phosphate and sodium citrate), antibacterial preservatives and some seasonings (such as Mexican pepper) are added and fully stirred to form a uniform and stable oil-in-water emulsion system.
Through this process, some characteristics of cheese have been improved:
(1) Emulsifiability becomes better. When cheese is heated and melted, water and oil will not separate. For example, when a hamburger is heated, a thin slice of cheese will melt, but the texture and taste will not change.
(2) The shelf life is prolonged. Quality assurance includes two aspects. First, by adding preservatives, mold and deterioration are inhibited, and the eating time of cheese is prolonged. Secondly, by adding emulsified salt, cheese will not lose its original shape when sold in warm areas, thus prolonging the time for cheese to maintain high quality.
(3) Rich flavor. Because of the seasoning and natural cheese used to make processed cheese, it can be a mixture of many different flavors of cheese.
(4) It has expansibility and popularization. If it is made into cheese sauce dipped in bread (such as pretzels), this process can make the cheese sauce silky and not easy to agglomerate.
Goal 2. Solve the leftovers of natural cheese. Natural cheese will eventually be cut into beautiful shapes for sale, leaving irregular edges and corners, or some natural cheese can't be sold and piled up in the warehouse, so use it as processed cheese ~
Three. Shelf life and storage method
Natural cheese needs refrigeration. Fresh cheese (the name of a cheese refers to fresh mozzarella cheese, whey cheese, cottage), a few days to two weeks; Soft cheese, 1 week; Semi-soft cheese, 2~3 weeks; Hard cheese: 5 weeks; Very hard cheese: 10 week. Processed cheese belongs to soft or semi-soft cheese, which can be stored for 3~4 weeks without refrigeration.
How to judge processed cheese?
After having a basic concept of two kinds of cheese, there are other ways to judge besides the instructions on the package:
1. Many sliced cheeses in sandwich burgers are processed cheeses. For example, American cheese American cheese (this is the name of the variety, not the place of origin).
2, you can dip cookies, and the cheese sauce with good fluidity is the processed cheese.
3. Cheese that doesn't need refrigeration is processed cheese.
4, natural cheese is expensive, and recycled cheese is cheap.
About how to choose cheese:
1, according to taste: undoubtedly the most important factor. You won't know until you eat it.
2, according to nutrition: the nutrition of cheese mainly comes from high protein. Processed cheese has a low proportion of natural cheese, containing many additives and salt. The nutritional value is naturally not as good as natural cheese. What are the nutritional differences between different kinds of natural cheese? Depending on the content of protein and fat, high protein, low fat, low salt and low sodium are ideal. At this time, you can just look at the nutrition label on the cheese, or refer to this webpage:
Comparison of nutritional information of dairy products
3. By use: For China people, there are basically three uses: (1) in hamburgers (2) for baking and cooking, such as making cheesecake, pizza and cheese baked rice (3) for direct consumption as snacks. The first kind of cheese has a wide selection, such as sliced cheese, cheddar cheese, Swiss cheese, Monterey Jack cheese, Colby cheese, etc., as long as it melts, it can basically retain the original shape of cheese. The second kind is mozzarella, mascarpone, cheddar, whey cheese and so on. The third use requires the highest quality cheese. It's best to buy a piece of cheese, cut or slice it yourself and taste it slowly. It can go with red wine.
Common cheese with high acceptance in China:
1, Swiss cheese and little Switzerland. A common cheese with holes in cats and mice is called Swiss cheese. These pores come from carbon dioxide produced during microbial fermentation.
2, the car hit the cheese cheddar cheese. Mild and moderate are easy to accept, sharp and ultra-sharp should not be tried easily.
3. mozzarella cheese. More common in pizza and roasted rice.
4. Parmesan cheese. Parmesan cheese in China is mostly powdered (cheese powder), which is sprinkled on pizza and roasted rice to increase flavor.
5, fresh cheese, such as cottage, whey cheese, fresh mozzarella, the first two are eaten directly, mixed with salad, and the last one is rolled with sliced tomatoes.
6, cream cheese cream cheese, mostly used to make cheesecake.
Don't try cheese easily;
1, cheese fermented by mold, usually has a strong taste, which is unacceptable for the first time. (。 . . . Some people, such as me, still have a hard time accepting cheese for a long time ...) Representative: blue cheese.
2. Sharp and extra sharp cheese refers to cheese whose fermentation period exceeds 65438+2 months or even 3-5 years. Old, too strong! Although some people like it. . .
It took me more than an hour to write a long answer for the first time, so I was tired. Although I am a graduate student majoring in food science, my major is not cheese, and my understanding of it is limited to a dairy course I attended and my life experience. If you have a one-sided understanding, it is entirely possible, please advise.
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# Standards for processed cheese and processed cheese food #, FDA, USA, 2006.
Pasteurized processed cheese
Ingredients: contains natural cheese or enzyme modified cheese, emulsifier & lt3% (w/w), acidulant (vinegar, lactic acid, citric acid, acetic acid and phosphoric acid), cream (from cream, anhydrous cream or dehydrated cream; & lt5% w/w), water, salt, pigment, perfume, flavoring agent, mildew inhibitor 1 (sorbic acid, potassium sorbate, sodium sorbate; < 0.3% w/w), anti-sticking agent 1 (lecithin < 0.03% by weight). Moisture: & lt40% (weight ratio); Fat: & GT30% (w/w); pH:& gt； 5.3
emulgator
The pasteurized cheese food must contain at least 5 1% natural cheese, and the remaining 49% must contain no more than 44% water. And at least 23% milk fat.
Ingredients: natural cheese and enzyme modified cheese. 565438+ 0% (w/w) of the final product, all ingredients allowed in processed cheese, milk, skim milk, buttermilk and cheese whey. Moisture: & LT44% (w/w); Fat: & gt23% (weight ratio); pH:& gt； 5.0
Processed cheese spread is a kind of processed cheese food, which can contain up to 44%~60% moisture and at least 20% milk fat. Besides emulsified salt and seasoning, the formula can also contain sweeteners and polysaccharide stabilizers such as xanthan gum and carrageenan.
Ingredients: natural cheese and enzyme modified cheese. 565438+ 0% w/w of the final product) all ingredients allowed in processed cheese food, as well as edible gum, sweetener and nisin (< 250 ppm). Moisture: 44-60% (weight ratio); Fat: & gt20% (weight ratio); pH:& gt； 4.0
If you are very interested in processed cheese, I suggest reading this review: processed cheese: comments by Rohit Kapoor and Lloyd E. Metzger in science and technology.
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