Sour Cream

Sour cream results from the souring, by lactic acid producing bacteria, of pasteurized cream. The science behind the transformation of milk or cream into sour cream: Bacteria feed on the lactose, or milk sugar, and produce lactic acid. This increases the acidity of the liquid and causes it to "sour" i.e., to coagulate and form solids.

Sour cream may be prepared from cream with different fat contents, according to its intended culinary use. Cream is fermented using a DL starter culture (Undefined mesophilic mixed) and should contain diacetyl as the major flavor compound.

The fat content of sour cream, also known as cultured cream, ranges from 10% to more than 40%. Because of the high fat content, the mouth-feel is smooth and the acidity seems milder than in a low-fat product, even though the pH in the water phase is the same in all of these products.

Among the important flavor compounds in sour cream include diacetyl, acetic acid, acetaldehyde, and dimethyl sulfide. All aroma compounds are associated with mesophilic heterofermentative starter culture metabolism. Sour cream is highly viscous and should be smooth and free of particulate matter.

Sour cream is produced by the fermentation of high-pasteurized cream. It is then homogenized at a low temperature (60-65°C). Temperature homogenization is preferred to promote formation of fat clusters, which during ripening flocculate and also increase the viscosity of the product and improve the texture.

The starter cultures typically used for making sour cream are aromatic starters (i.e., Lc. lactis subsp. lactis biovar. diacetylactis and L. mesenteroides subsp. cremoris). The inoculated cream is then incubated at a temperature of 22°C and allowed to develop titratable acidity and desired body and texture. Usually, it takes 10-12 hrs. to attain the desired acidity.

Sour cream is used as a thickener, but when using for soup or hot sauces. Sour cream is predominantly utilized as an accompaniment with warm entrees such as baked potatoes and burritos. Sour cream must remain viscous without whey separation when placed on warm food.
Sour Cream