Sour cream

[3] According to US (FDA) regulations, commercially produced sour cream contains no less than 18% milkfat before bulking agents are added, and no less than 14.4% milk fat in the finished product.

[2] In addition, according to the Canadian food regulations, the emulsifying, gelling, stabilizing and thickening agents in sour cream are algin, carob bean gum (locust bean gum), carrageenan, gelatin, guar gum, pectin, or propylene glycol alginate or any combination thereof in an amount not exceeding 0.5 percent,[2] monoglycerides, mono- and diglycerides, or any combination thereof, in an amount not exceeding 0.3 percent, and sodium phosphate dibasic in an amount not exceeding 0.05 percent.

[2] Sour cream is not fully fermented, and like many dairy products, it must be refrigerated both before and after opening the sealed container.

Additionally, in Canadian regulations, a milk-coagulating enzyme derived from Rhizomucor miehei (Cooney and Emerson) from Mucor pusillus Lindt by pure culture fermentation process or from Aspergillus oryzae RET-1 (pBoel777) can also be added to the sour cream production process in an amount consistent with good manufacturing practice.

[6] Processed sour cream can include any of the following additives and preservatives: grade A whey, modified food starch, sodium phosphate, sodium citrate, guar gum, carrageenan, calcium sulfate, potassium sorbate, and locust bean gum.

The common stabilizers that are added to sour cream are polysaccharides and gelatin, including modified food starch, guar gum, and carrageenans.

Stabilizers provide a smoother texture, create specific gel structures, and reduce whey syneresis.

The homogenized cream undergoes high temperature short time (HTST) pasteurization method.

The starter culture initiates the fermentation process by enabling the homogenized cream to reach a pH of 4.5 to 4.8.

To avoid phase separation brought on by the increased surface area, the fat globules readily bind with the denatured β-lactoglobulin.

When this decrease begins, dissolution of calcium phosphate occurs, and causes a rapid drop in the pH.

The casein proteins enter a more ordered system, attributing to a strong gel structure formation.

The whey proteins that were denatured in the heating steps of processing, are insoluble at this acidic pH and are precipitated with casein.

[22] At the isoelectric point, the net surface charge of casein micelle is zero and a minimum of electrostatic repulsion can be expected.

[27] The thixotropic properties exhibited by sour cream are what make it such a versatile product in the food industry.

Sour cream is commonly used as a condiment on foods, or combined with other ingredients to form a dipping sauce.

It can be added to soups and sauces to help thicken and make them creamy, or in baking to help increase the moisture level over and above using milk.