Food or edible material: processes – compositions – and products – Processes – Freeze drying or freeze concentrating
Reexamination Certificate
1999-01-05
2001-02-06
Weier, Anthony J. (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Freeze drying or freeze concentrating
C426S616000, C426S524000, C426S640000
Reexamination Certificate
active
06183795
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method and apparatus for producing shattered, dried, preservative-free pieces of edible plant material (fruit pieces or vegetable pieces). In particular, the invention relates to a method and apparatus for producing shattered, preservative-free dried fruit (or vegetable) pieces with a random shaped appearance that do not tend to absorb moisture and lose their integrity quickly.
BACKGROUND OF THE INVENTION
Throughout this specification (including in the claims), the expression “edible plant material” is used to denote edible fruit or vegetable material, and “pieces of edible plant material” denotes edible fruit pieces or edible vegetable pieces.
Small dried fruit pieces are a popular industrial food ingredient used in baking, trail mixes and cereal applications.
Conventional dried fruit pieces are often sticky and tend to clump together unless coated with cornstarch, vegetable oil or other non-stick coating agents. Fruit pieces without preservatives are difficult to store at moisture contents greater than 25% because of the increased risks of yeast and mold growth. At moisture contents below 25% there is generally not enough free water to support growth of yeast and mold.
One method of manufacturing fruit pieces is to form ground fruit paste into strips, and dice or cut the strips into square or rectangular bits. Another method entails blending and extruding finely ground or chopped diced fruit with functional ingredients (which can include colors and flavors) and coating the resulting pieces with non-stick coatings to prevent clumping. However, both of these methods produce pieces that tend to absorb moisture and lose their integrity rapidly.
U.S. Pat. No. 4,948,679, issued Aug. 14, 1996, discloses a process for freezing and thawing and then vacuum drying fruits and vegetables to produce crispy and tender puffed food products.
An English language abstract of Japanese patent application 58134942A discloses a method of processing fruit by rapid freezing at low temperature, pulverizing the fruit at low temperature and defrosting the pulverized fruit with the addition of gum arabic and/or sugar. Although useful in jams and jellies, pulverized fruit particles are too small to be useful as a snack food item or as an ingredient where larger particulates are desired. In addition, pulverized fruit particles, when molded, diced, or otherwise formed into larger pieces, tend to absorb moisture and lose their integrity rapidly.
It would be advantageous to have a process for producing preservative-free shattered fruit (or vegetable) pieces that have a useful size and a random shaped appearance, and do not tend to absorb moisture and lose their integrity as quickly.
SUMMARY OF THE INVENTION
Preferred embodiments of the present invention are methods for producing shattered, dried, preservative-free pieces of edible plant material (fruit pieces or vegetable pieces). In the first step of a first embodiment of such a method, low moisture (22-30%) fruit is cryogenically frozen (e.g., by immersion in liquid nitrogen for a period of approximately 5-15 minutes, preferably 12 minutes, or with CO
2
snow). In the second step, the frozen fruit is impacted to break the fruit into useful-sized frozen pieces (preferably having size primarily in the range ¼ inch to ⅜ inch, in the sense that most or all of them have size not greater than ⅜ inch and not less than ¼ inch). A third step is then performed if the pieces resulting from the second step have a moisture content greater than 25% (or if an undesirably large amount of moisture would condense on the pieces from ambient atmosphere, during thawing in the ambient atmosphere at room temperature). In the third step, the frozen fruit pieces are warmed and dried (or warmed in a dry environment) to produce thawed pieces having moisture content in the range from 22% to 25% (by weight).
In one implementation of the first embodiment of the inventive method, the frozen fruit is crushed between rollers of a dual pass roller mill during the second step of the process. In another implementation of the first embodiment, the frozen fruit is shattered in a rotating tumbler during the second step of the process. In a third implementation of the first embodiment, the frozen fruit pieces are warmed in a drier at temperatures between 150° F. and 180° F. in the third step of the process. In some implementations of the first embodiment, the fruit is selected from the group consisting of prunes, raisins, dried pears, dried peaches, dried apricots, dried apples, dried nectarines, dried figs, and dried dates.
In other implementations of the first embodiment, edible vegetable material (e.g., carrots, squash, zucchini, potatoes, broccoli, onions, cauliflower, celery, or peppers) is substituted for fruit.
In another embodiment, the invention is a method for producing shattered prunes, comprising, in order, the steps: a) increasing the moisture content of dried prunes to 26-30%, preferably 28-29%, to produce low moisture prunes; b) pitting the prunes; c) cryogenically freezing the low moisture pitted prunes to form frozen prunes; d) impacting the frozen pitted prunes with a dual pass roller mill to form primarily ¼ to ⅜ inch frozen fruit pieces; and e) warming the frozen prune pieces to maintain or reduce the moisture content to 22-25% prior to storage (if the frozen fruit pieces have a moisture content greater than 25% upon completion of step d) or if an undesirably large amount of moisture would condense on the pieces from the ambient air during thawing in the ambient air at room temperature). An undesirably large amount of moisture should not be allowed to condense on the pieces from the ambient air during thawing.
Another aspect of the invention is an apparatus for implementing any embodiment of the inventive method.
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patent: 4762725 (1988-08-01), Player et al.
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patent: 43 34 322 A1 (1995-04-01), None
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Database Abstract. AN 80(08):J1151 FSTA from Report, Internation Federation of Fruit Juice Producers, Scientific-Technical Commission, No. 15, pp. 363-372. Author: Moutounet, 1978.
Supplementary European Search Report ( EP 98 98 3221).
Database WPI, Section Ch, Week 199252, Derwent Publications, London, GB, XP 002142192, 15 Feb. 1992.
Greenberg & Traurig, LLP
Sunsweet Growers, Inc.
Weier Anthony J.
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