Sour cream

Cells of microorganisms have constituted a portion of human food siace ancient times. Yeast-leavened baked products contain the residual nutrients from the yeast cells destroyed duriag bakiag (see Bakery processes and leavening agents). Cultured dairy products, such as yogurt, buttermilk, and sour cream, contain up to lO cells of lactic acid bacteria per gram (19) (see Milk and milkproducts). Other examples of fermented foods consumed siace early times iaclude fermented meats, fish, and soybean products. 

The composition of dairy substitutes is highly variable and generally represents the least-cost formulation consistent with consumer acceptance of the product. These imitations invariably have lower fat and protein levels than the dairy products that they are made to resemble. The gross compositions of filled milk, meUorine, synthetic milk, sour cream, coffee whiteners, whipped toppings, and cheese are Hsted in Table 10. A comparison of the composition of certain dairy products and their substitutes is presented in Table 11. 

Ingredient Whole milk A B C A B C A B Nondairy sour cream Liquid coffee whiteners Whipped toppings Cassinate-based cheese... 

Miscellaneous. Miscellaneous products having market significance iaclude sour cream, chip dips, milkshake bases, puddings, yogurt and fat-reduced forms of all substitute dairy foods. These products have been formulated from both caseiaates and soybean proteias. 

Gelatin is very familiar as the gelling agent in Jell-O desserts. It is also used to thicken yogurt, sour cream, and ice creams. In its dried form it is used to make the dissolvable capsules that make medicines easier to swallow. 

Acids and bases are determined by their properties. The word acid comes from the Latin word acidus, which means sour. For example, lemon juice tastes sour because it contains citric acid. Sauerkraut, another sour-tasting food, is cabbage fermented in lactic acid. In fact, sauer (pronounced almost exactly like the English word sour) in German means acid. Sour cream also has lactic acid in it. 

The mechanical breaking of colloids is also essential when making butter from milk the solid from soured cream is churned extensively until phase separation occurs. The water-based liquid is drained away to yield a fat-rich solid, the butter. 

Antibiotics in milk can affect dramatically the production of fermented dairy products such as cheese, yogurt, buttermilk and sour cream. Routine application of antibiotic test kits such as the Delvo kit are required to avoid major losses on the line. 

Avoid high-tyramine foods cheese (aged), sour cream, beer, wine, pickled products, liver, raisins, bananas, figs, avocados, meat tenderizers, chocolate,yogurt soy... 

Apart from public health impacts, residual antimicrobials in animal products can bring about technoeconomic losses in the food processing industry. It has long been known that the presence of some antimicrobial compounds in milk can dramatically affect the production of fermented dairy products such as yogurt, cheese, buttermilk and sour cream (72, 73). As shown in Table 10.2, even minute concentrations of antibiotics in milk can cause inhibition of the growth of commonly used dairy starter cultures (74). 

The term aqueous phase separation is often more simply described as oil-in-water microencapsulation. The two encapsulation processes described above are examples of this oil-in-water encapsulation. In this process the core material is the oil and it should be immisible in the continuous phase, namely water. A commercial example of aqueous phase separation would be the microencapsulation of an oily flavor such as sour cream with a gelatin wall. These microcapsules would then be dispersed in a dry cake mix. The mechanism of release would be during the moist baking cycle of the cake, moist-heat causing the capsule walls to first swell and then rupture. 

Milk and milk products purchased by the consumer in liquid or semiliquid form generally are classified as fluid milk or cream. Fluid milks include all of the plain milk products, with fat contents varying from those of whole to skim milk, as well as flavored and fermented milks. Creams include products varying in fat content from half and half to heavy whipping cream to fermented sour cream. Products from each category are described briefly, with information on their composition. 

Sour cream is cream that has been soured by lactic acid bacteria or by directly adding food-grade acids. According to U.S. federal standards, both sour cream and acidified sour cream must contain not less than 18% milk fat with a titratable acidity of not less than 0.5% expressed as lactic acid (FDA 1981A). Optional ingredients are used to improve... 

Sour cream is prepared by mixing milk fat and skim milk, nonfat solids, and other ingredients. The mix is then pasteurized, homogenized, and cooled to the setting temperature starter and enzymes are then added, and the cream is allowed to ripen. After ripening, it is cooled for 24 hr before packaging. 

Schanback, M. 1977. Manufacture of superior quality sour cream. Cult. Dairy Prod. J. 12 (2), 19-20. 

Milk can be converted easily by lactic acid starter cultures into various cultured and culture-containing milk products. Within the last ten years, consumption of these products (e.g., yogurt, sour cream, and acidophilus milk) has increased appreciably in the United States. (Rasic and Kurmann 1978 Shahani and Chandan 1979 Helferich and... 

Goel, M. C., Kulshrestha, D. C., Marth, E. H., Francis, D. W., Bradshaw, J. G. and Read, R. B., Jr. 1971. Fate of coliforms in yogurt, buttermilk, sour cream, and cottage cheese during refrigerated storage. J. Milk Food Technol. 34, 54-58. 

Minor, T. E. and Marth, E. H. 1972. Fate of Staphyloccus aureus in cultured butter-milk, sour cream, and yogurt during storage. J. Milk food TechnoL 35, 302-306. 

Vedamuthu, E. R. 1974. Cultures for buttermilk, sour cream and yogurt with special comments on acidophilus yogurt. Cultured Dairy Prod. J. 9, 16-21. 

Taste is only one of several qualities of a process or product that is affected by an excess of either of these 10ns. Some raw materials are naturally too acidic, others too alkaline—so that neutralizers must be added to adjust the pH within an acceptable range. In die dairy industry, for example, the acid in sour cream must be adjusted by the addition of alkaline compounds in order that satisfactory butter can be churned. Quite often, the pH may be difficult to adjust or to maintain after adjustment. Stability of pH can be accomplished by the addition of buffering agents that, within limits, effectively maintain the desired pH even when additional acid or alkali is added. For example, orange-flavored instant breakfast drink has just... 

Lactic Fermentation—in which lactic acid is produced. This is an important fermentation for the preservation of food. Ixtclohacillits bitlgaricus. L, casei. and Streptococcus lartis are used for the manufacture of dairy products, such as sour cream. Lactobacillus plunlariim is used in lhe preservation of certain vegetables, such as the production of pickles and kraut. 

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