Calcium fortified dairy products

Abstract

Nutritionally improved cultured dairy products such as yogurt products include a fine powdered calcium phosphate salt of reduced particle size having a mean diameter ≦6 μm in amounts sufficient to provide a total calcium content of 0.25% to 0.75%. A method for producing the calcium fortified yogurt is also provided wherein an fine powdered insoluble calcium salt is admixed with a milk blend prior to fermentation. The yogurt is prepared by conventional fermentation. Both stirred style and cup set style yogurt products can be prepared.

Description

FIELD OF THE INVENTION [0001] This invention relates to food products, especially refrigerated fermented dairy products such as yogurt that are calcium fortified and to their methods of manufacture, and more specifically to yogurt fortified with calcium. BACKGROUND OF THE INVENTION [0002] The present invention provides improvements to those calcium fortified yogurt products and methods of preparation that are described in U.S. Pat. No. 5,820,903 entitled “Calcium Fortified Yogurt and Methods of Preparation” (issued Oct. 13, 1998 to Fluery et al.) and which is incorporated herein by reference. The '903 patent describes the post fermentation addition of a calcium phosphate having a particle size of less than 150 microns to produce a calcium fortified stirred style yogurt. In important part, the present improvement resides in selecting and adding a more fine powder form of calcium phosphate having a particle size of less than six microns to a milk base prior to fermentation. By utilizi...

AI Technical Summary

Benefits of technology

[0053] Thereafter, the homogenized and pasteurized milk blend is inoculated with a desired culture 20. Usually, a combination of Lactobacillus bulgaricus and Streptococcus thermophilus bacteria is added to begin the fermentation process. In other variations, Lactobacillus acidophilus or L. bifidus can also be added. The present methods further essentially comprise fermenting 22 or culturing the inoculated milk blend to desired endpoints of pH, titratable acidity, time, etc. to provide a warm cultured dairy product such as a yogurt 23. The fermentation step 22, is continued an in highly preferred embodiments, quiescently continued (i.e., without agitation), until the pH of the milk blend reaches approximately 4.4 to 4.6 to form the yogurt base. Depending upon temperature and amount of culture added, this can take from about three to about 14 hours. It is important that the mixture not be agitated during the fermentation process to allow proper curd formation. It is an advantage of the present invention that by selection of such a finely powdered calcium phosphate that surprisingly, the added calcium material does not settle out during fermentation even when quiescently practiced.

[0054] The particular fermentation endpoint pH can vary modestly. Typically, the endpoint pH can range from about 4.2 to 4.6, preferably about 4.45 to 4.55.

[0055] When the proper pH has been reached, the present methods further essentially comprise cooling 24 the warm yogurt (e.g., to about 2 to 21° C., preferably about 5° C.) to arrest further growth and any further drop in the pH to form a cooled yogurt 28 or calcium fortified yogurt base.

[0056] The yogurt base 28 thus prepared importantly is characterized by a viscosity of at least 1500, preferably at least 2300 cps (at 5° C.). Such a viscosity is helpful to suspending the insoluble calcium salt. At a viscosity of 1500 cps, the yogurt is a thinner substance useful for a yogurt beverage-type product. Yogurt viscosities can range up to 25000 cps.

[0057] While the above described particular process can be used, any vat set fermented yogurt can be used.

[0058] Moreover, although a live yogurt product is preferred, the present invention can also be used in yogurt-based foods as distinguished from a yogurt product. For example, a shelf stable yogurt-based product is prepared by heat treating a yogurt to inactivate the culture and packaging aseptically (not shown). In this variation, the pH of the yogurt based product can be adjusted for taste or for compatibility with other ingredients. For example, the pH can be adjusted upwards substantially for a chocolate flavored yogurt based product.

Problems solved by technology

This problem is even more severe for yogurt products containing up to about 20% fruit sauce since such fruit materials are low in native calcium content.

Serious practical difficulties have been encountered in incorporating supplemental calcium into dairy products because most calcium salts have very low solubility in milk.

Added calcium salts, being generally insoluble and not suspended by casein, therefore tend to settle out, frustrating attempts to maintain uniform dispersions during manufacture.

This problem of suspending insoluble calcium salts is compounded by the fact that generally the yogurt base should not be agitated during the incubation period, i.e., the yogurt should be quiescently fermented.

Thus, in the manufacture of yogurt using vat incubation, the required lack of agitation during incubation can cause a substantial portion of an insoluble calcium salt to settle to the bottom of the vat.

In light of these cleaning difficulties, this process is not only impractical using conventional yogurt manufacturing equipment, but also is likely to adversely affect the texture of the product.

Settling can result in a product unacceptable to the consumer.

Usage of such required chelating, however, can adversely affect the flavor of the product.

More importantly, however, the cost of the calcium source is prohibitive for a commercially practical product.

While useful, such formulations require addition of expensive special ingredients or extensive processing to form the materials in situ.

While useful, not all yogurt flavors popular today contain fruit.

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