Food or edible material: processes – compositions – and products – Product with added vitamin or derivative thereof for...
Reexamination Certificate
2000-09-01
2002-07-23
Pratt, Helen (Department: 1761)
Food or edible material: processes, compositions, and products
Product with added vitamin or derivative thereof for...
C426S073000, C426S074000, C426S321000, C426S335000, C426S800000
Reexamination Certificate
active
06423354
ABSTRACT:
This invention relates to nutritionally balanced food compositions, which may be used for oral ingestion or for ingestion along the digestive tract and a process for manufacturing such food compositions. More particularly, the invention relates to nutritionally balanced liquid food compositions which have a low pH, extended shelf life, high antimicrobial activity, and which include protein in solution and in colloidal suspension or, alternately, in only colloidal suspension. The primary protein source for the food composition is milk proteins, including caseins.
BACKGROUND OF THE INVENTION
Liquid nutritionally balanced food compositions are known in the art. See, for example, my U.S. Pat. No. 4,931,300 for “ANTIMICROBIAL FOOD COMPOSITION”.
Liquid nutritionally balanced powdered food compositions like those described in my U.S. Pat. No. 4,931,300 have several potential disadvantages. Protein tends to precipitate from liquid solutions which, like the food composition in U.S. Pat. No. 4,931,300, have acidic pH values in the range of 2.0 to 5.5. In particular, protein tends to precipitate from such liquid solutions when the solutions are heated to a high temperature to sterilize the solutions. Solutions with low pH values in the range of 2.0 to 5.5 are often preferred for nutritional food compositions because the acidity of the solutions normally provides a high level of antimicrobial activity. However, even the food composition in my U.S. Pat. No. 4,931,300 must be refrigerated after it is reconstituted and must then be utilized within about seventy-two hours. Even though the seventy-two hour shelf life of the reconstituted food composition is relatively short, it is still substantially longer than the shelf life of other comparable food compositions. See, for example, U.S. Pat. No. 4,112,123 to Roberts, where the shelf life of a comparable reconstituted refrigerated food composition is only about twenty-four hours.
Some attempts to address these and other problems are illustrated in my U.S. Pat. Nos. 5,156,875 and 5,614,241. Each of these patents utilize a water soluble protein, preferably whey protein, in conjunction with a protein stabilizer system to control precipitation of the proteins out of the aqueous food composition.
In practice, however, the food compositions of the type described in U.S. Pat. Nos. 4,112,123, 4,931,300, 5,156,875 and 5,614,241 have each encountered continued problems with precipitation of the proteins during storage in liquid form or after reconstitution with an aqueous medium such as water. The food compositions of U.S. Pat. Nos. 5,156,875 and 5,614,241 have both been found to undergo significant precipitation of the proteins after sterilization and packaging, thereby reducing the viable shelf life of the product.
Additionally, the prior food compositions of U.S. Pat. Nos. 4,112,123, 4,931,300, 5,156,875 and 5,614,241 all required aseptic sterilization and packaging. Aseptic sterilization, also called high temperature/short time (HTST) sterilization, is a more restrictive, slower and more expensive process than the general commercial retort sterilization used in typical canning processes for food products. Aseptic sterilization is also a more cumbersome commercial process as the product and the packaging must each be separately sterilized prior to packaging the product. By contrast, retort sterilization allows both the packaging and the food product within it to be sterilized simultaneously, a process much more adaptable and useful in mass production/canning operations. However, because retort sterilization is a much more vigorous sterilization process than aseptic sterilization, utilizing higher time heat ratios and longer sterilization times. Retort sterilization is unsuitable for the prior art food compositions because such compositions break down and form precipitants during the longer periods during which the product is held at high temperature which characterize commercial retort sterilization processes.
Finally, prior nutritionally balanced low pH food compositions have required careful selection of the particular proteins to be used due to solubility considerations affecting precipitants. For this reason, food compositions such as those disclosed in my prior patents described above relied upon the use of previously hydrolized proteins or water soluble proteins. In practice, the useful water soluble proteins consisted entirely of whey protein. Whey proteins are known to be useful in nutritional food compositions because they have high nutritional value. However, whey proteins comprise only about 20% of the highly nutritional proteins which are derived from milk.
Milk proteins have excellent nutritional and functional properties and are widely used in the manufacture of food products. Different functionality, composition and flavor of milk protein products make them ideal for a number of uses. Milk protein is a rich source of essential amino acids. Milk is made up of approximately 3-5 percent protein which can be classified into two basic types, casein proteins and whey proteins. About 80 per cent of the protein content is casein which occurs as complexes or micelles in fresh milk, while the whey proteins are soluble in the milk's serum phase. However, caseins have not been utilized in prior low pH, nutritional food compositions due to their insolubility and concomitant tendency to form precipitants.
Casein forms the largest part of the total protein content in cow's milk—around 80 percent—and so it is a valuable component. All casein products are manufactured from skim milk using a similar basic process: the casein is separated from the milk, purified by washing, and dried. However, the process is a little different according to whether acid or rennet casein is being made.
The first stage of making lactic acid casein is similar to cheese making. A ‘starter’ is added to the skim milk—a natural bacteria which converts the milk sugar (lactose) into lactic acid. After about 15 hours, the casein becomes insoluble and is separated from the whey. The casein is then washed in water four times to remove the remaining lactose and minerals, and dried in hot air until the moisture content is less than 12 percent. It is ground to a fine powder and bagged, with the final product containing more than 85 percent protein.
A more direct approach to precipitating the casein is to add a mineral acid directly to the skim milk.
In its insoluble form, acid casein does not presently have many uses. To make it soluble, the casein is neutralized by adding an alkali. Alternatively, caseinates (which have different properties from casein) can be made by adding different dissolving salts to the insoluble acid casein. Both acid casein and caseinates, the salts of caseins, are widely used in the food industry and they have some technical uses also. Caseinates are made by dissolving acid casein in a suitable hydroxide and drying it to make a water soluble product.
Rennet casein is produced by adding a rennet enzyme to the skim milk. A gel forms after about 20 minutes which is then ‘cooked’ to form a mixture of casein and whey. The process of manufacturing rennet casein is similar to the manufacture of acid casein. Rennet casein is mainly used to make imitation cheese (which has an important role in the fast food trade), although some is also used to manufacture plastic products such as buttons. Rennett casein is generally used in the manufacturing of products. Because of its good dye binding ability and excellent extrusion properties, it is ideal for use in plastics such as buttons, beads, buckles, knitting needles, and high quality plastics for jewelry.
Casein is a naturally occurring protein and is specific and identifiable in terms of its composition and, for purposes of the present invention, is not necessarily dependant upon a process for production thereof.
Casein is the primary protein in manufactured milk portein isolates, also known as total milk proteins. Such milk protein isolate products contain all of the proteins found in milk and generally are about
Miller & Martin LLP
Pratt Helen
LandOfFree
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