Food or edible material: processes – compositions – and products – Processes – Separating a starting material into plural different...
Reexamination Certificate
1999-07-28
2001-05-01
Weier, Anthony J. (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Separating a starting material into plural different...
C426S480000, C426S482000, C062S062000, C062S063000, C062S064000, C062S373000, C062S374000
Reexamination Certificate
active
06224932
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention (Technical Field)
The present invention relates to selective modification of rheological properties of foodstuffs to enhance processing. More specifically, the present invention enhances tree nutshell fracturing processes by contacting tree nuts with a cryogen.
2. Background Art
Food processing generally adds value to raw or commodity foodstuffs. Often raw foodstuffs must be ground, milled, fractured or crushed to produce a final marketable product. Rheological properties of foodstuffs govern the selection and ultimately the efficiency of such processes. Rheological properties determine how materials flow or deform. For instance, hydration typically reduces the Young's modulus (a parameter used to help characterize the relationship between stress and strain) and yield stress of foodstuffs like starch grains. A reduced Young's modulus corresponds to an increase in strain for a given amount of applied stress whereas a reduced yield stress means that the foodstuff will fracture or shear at a reduced applied stress. High levels of hydration may minimize or even eliminate fracturing, in such instances, the yield stress corresponds to shearing or the point where the applied stress causes the foodstuff to flow. Other processes such as freezing affect the rheological properties of foodstuffs differently. Freezing usually increases the Young's modulus; however, the yield stress may increase or decrease depending on the physical structure of the foodstuff. In the case of foodstuffs with a substantial water activity, the time-temperature curve, i.e., the rate of cooling, often determines crystal size. For example, slow freezing produces larger crystals whereas rapid freezing produces smaller crystals, Furthermore, slow freezing segregates soluble materials more so than rapid freezing. Although frozen foodstuffs almost always have a higher Young's modulus, those with larger crystals frequently fracture differently than those with smaller crystals. To facilitate fracturing, a high Young's modulus and a lower yield stress are desirable.
The following U.S. Patents disclose methods for cooling foodstuffs using cryogens: U.S. Pat. No. 5,333,802, entitled “Method and apparatus for producing chunks or kibbles of a foodstuff,” to Seelig et al., discloses use of a liquid cryogen to alter rheological properties of foodstuffs prior to chunking or kibbling. U.S. Pat. No. 4,742,686, entitled “Process for increasing tree nut shelling efficiency,” to Cook, discloses use of a cryogen to freeze tree nuts whereby nut kernals become harder than nutshells. U.S. Pat. No. 4,436,757, entitled “Cryogenic process for decortication and hulling of sunflower seeds,” to Lange et al., discloses use of cryogen diffusion into sunflower seeds followed by rapid heating to cause gas expansion and hull separation. U.S. Pat. No. 4,177,296. entitled “Process for the preparation of peanut-curd.” to Mochizuki et al., discloses cryogenic cooling and pulverizing of pressed peanuts to obtain a peanut-curd. U.S. Pat. No. 4,004,037, entitled “Peanut butter manufacture,” to Connick, discloses use of cryogens for preparation of peanut butter in a non-oxidizing, low-temperature environment. U.S. Pat. No. 3,452,936, entitled “Reduction of cereal grains to flour,” to Hanser, discloses use of cryogenic conditions for processing cereal grains. U.S. Pat. No. 3,413,818, entitled “Immersion freezing,” to Pelmulder, discloses cyrogenic processing of foodstuffs for storage or for subsequent freeze-drying. U.S. Pat. No. 3,214,928, entitled “Method and apparatus for freezing food products,” to Oberdorfer, discloses spraying and showering of cryogenic fluids for freezing food products.
SUMMARY OF THE INVENTION (DISCLOSURE OF THE INVENTION)
The present invention is of a method and apparatus for cryogenic rheological modification of shelled foods comprising: providing a shelled food comprising an exterior shell and interior meat and briefly exposing the shelled food to a cryogen to substantially modify rheology of the exterior shell while substantially leaving rheology of the interior meat unaffected. In the preferred embodiment, the present invention further comprises hydrating the shelled food. Preferably, the preferred embodiment comprises providing, for example, nuts (for example, tree nuts), crustaceans, or mollusks. For hydrating of tree nuts a hydrated moisture content of between approximately 5% by weight and approximately 7% by weight is preferred. Exposing comprises briefly exposing shelled food to a cryogen for a time sufficient to enhance fractureability of the shells. The preferred embodiment additionally comprises modifying after exposing, wherein modifying may be fracturing shells of the shelled foods, shattering shells of the shelled foods, imploding shells of the shelled foods, exploding shells of the shelled foods, or combinations thereof. Modifying preferably occurs within approximately 10 seconds of exposing, employs an applied force at least 10% lower in force than an applied force necessary to modify the shelled foods in the absence of exposure to a cryogen and separates at least approximately 90% of the meats from the corresponding shells. Exposing preferably comprises exposing for less than approximately one minute, more preferably between approximately 3 and 16 seconds, and most preferably between approximately 6 and 15 seconds. Exposing also preferably comprises briefly exposing the shelled food to a cryogen having a temperature of at least 100 degrees Fahrenheit lower than a temperature of the shelled food and more preferably of at least 200 degrees Fahrenheit lower.
A primary object of the present invention is to selectively modify rheological properties of foodstuffs to enhance food processing.
A primary advantage of the present invention is enhanced processing of tree nuts whereby more intact nutmeats are recovered.
Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
REFERENCES:
patent: 3214928 (1965-11-01), Oberdorfer
patent: 3413818 (1968-12-01), Pelmulder
patent: 3452936 (1969-07-01), Hanser et al.
patent: 4004037 (1977-01-01), Connick
patent: 4177296 (1979-12-01), Mochizuki et al.
patent: 4436757 (1984-03-01), Lange et al.
patent: 4742686 (1988-05-01), Cook
patent: 4992289 (1991-02-01), Kiczek
patent: 5059151 (1991-10-01), Kiczek
patent: 5333802 (1994-08-01), Seelig et al.
Bivens, Jr. William W.
Rovirosa Sally Stahmann
Stahmann William J.
Myers Jeffrey D.
Pangrle Brian J.
Stahmann Farms, Inc.
Weier Anthony J.
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