Title:  Process for preparing fat soluble beadlets

United States Patent:  6,444,227

Issued:  September 3, 2002

Inventors:  Leuenberger; Bruno (Allschwil, CH); Tritsch; Jean-Claude (Saint-Louis, FR); Ulm; Johann (Oberwil, CH)

Assignee:  Roche Vitamins Inc. (Parsippany, NJ)

Appl. No.:  626976

Filed:  July 27, 2000

The invention relates to a process for preparing beadlets containing fat soluble substances in a gelatin matrix which comprises crosslinking the gelatin by radiation or enzymatically. Specifically, the invention relates to a process for preparing beadlets containing fat soluble substances having the steps of: (1) forming an aqueous emulsion of a fat soluble substance, a gelatin, a reducing agent; (2) converting the emulsion into a dry powder; and (3) crosslinking the gelatin matrix in the coated particles by exposing the coated particles to radiation or, in the case of a crosslinking enzyme being present, by incubating the coated particles.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term "fat soluble substance" refers to vitamins selected from the group consisting of vitamin A, D, E, K, and derivatives thereof, carotenoids, polyunsaturated fatty acids and flavoring or aroma substances as well as mixtures thereof. A preferred fat soluble substance is vitamin A and its derivatives, preferably vitamin A acetate or vitamin A palmitate. Suitable carotenoids include beta-carotene, astaxanthin, apocarotenal, canthaxanthin, apoester, citranaxanthin, zeaxanthin, lutein, and lycopenes, as well as mixtures thereof. Examples for polyunsaturated fatty acids include linoleic acid, linolenic acid, arachidonic acid, docosahexaenic acid, eicosapentaenic acid, and the like, as well as mixtures thereof.

As used herein, the term "reducing agent" refers to reducing sugars or reducing sugar derivatives. Preferred reducing sugar compounds are the monosaccharides, preferably pentoses and hexoses, and the oligosaccharides, preferably disaccharides. Examples of monosaccharides are glucose, fructose, galactose, mannose, talose, and invert sugar (mixture of glucose and fructose) as hexoses and arabinose, ribose and xylose as pentoses, threose as tetrose and glycerinaldehyde as triose. Examples of oligosaccharides are lactose, maltose, and the like. In addition, high fructose corn syrups (mixtures of fructose and dextrose) may also be employed in the practice of the invention.

As used herein, the term "antioxidant" includes butylated hydroxy anisole (BRA), butylated hydroxy toluene (BHT), ethoxyquin (6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline), tocopherols, and the like.

As used herein, the term "humectant" includes glycerol, sorbitol, polyethylene glycol, propylene glycol, and the like.

As used herein, the term "radiation" refers to any radiation source that will induce a reaction between the carbonyl group of the sugar with the free amino moiety of the gelatin molecule. Suitable radiation sources are light radiating in a range selected from the ultraviolet, visible, infrared or electromagnetic radiation sources such as microwaves.

As used herein, the term "microwaves" refers to electromagnetic waves having frequencies in the range of about 900 MHz to about 2.45 GHz. These waves are readily absorbed by dielectrics having a polar radical such as water. When such a dielectric is exposed to microwave energy at about 700 to about 1000 watts, its molecules are subjected to high-speed internal vibration which results in the generation of heat.

The crosslinking process is preferably carried out by microwave heating that provides a highly efficient heating and crosslinking effect. The beadlets crosslinked by applying microwave energy are insoluble in water and possess high stability, especially in feed production processes like extrusion and pelleting.

As used herein, the term "crosslinking enzyme" refers to transferases, particularly transglutaminases, which couple amino acids through the formation of a peptide bond. Thus, a reaction between the carbonyl group of the sugar with the free amino moiety of the gelatin molecule is catalyzed. A suitable transglutaminase is on the market under the trade name of ACTIVA TI.RTM. (Ajinomoto). The amount of the transglutaminase to be used is about 0.01 g/g to about 0.10 g/g gelatin.

Small quantities of other ingredients, e.g., emulsifiers, such as lecithin, extenders and solubilizers, and coloring agents can also be incorporated in the emulsions of this invention, as well as other excipients.

The first step of the process according to the invention involves emulsifying the fat soluble substance with water, gelatin and a reducing agent, and optionally with an antioxidant and/or a humectant.

The fat soluble substance can be present in an amount of about 1 wt % to about 80 wt %, preferably about 5 wt % to about 40 wt %.

Gelatin of any origin may be employed. Preferred gelatin is from pig or cattle, and have a Bloom No. of from 80 to 160, particularly 140. The gelatin may be present in an amount of about 5 wt % to about 70 wt %, preferably about 20 wt % to about 60 wt %.

The reducing agent can be present in an amount of about 2 wt % to about 20 wt %, preferably about 5 wt % to about 10 wt %.

The antioxidant can be present in an amount of about 2 wt % to about 15 wt %, preferably about 5 wt % to about 10 wt %.

The humectant can be present in an amount of about 2 wt % to about 20 wt %, preferably about 5 wt % to about 10 wt %.

The preparation of the emulsion can be carried out by methods that will be apparent to those skilled in the art. For example, the gelatin is dissolved in water with the aid of moderate heating, and the fat soluble substance is then dispersed or emulsified in the solution of the gelatin. The reducing agent, as well as any other ingredients, can be introduced into the mixture either before or after adding the fat soluble substance. The mixture is agitated until all dispersoids are uniformly distributed and, if necessary, by passing the mixture through a homogenizer.

The emulsion is then dried by known methods, e.g., by spray drying such as spraying into a collecting powder. In case of enzymatically crosslinking, the enzyme is added just before spraying the emulsion into the collecting powder. The particles containing the fat soluble substance formed in the collecting powder by known methods should be dried to a moisture content of less than 10%.

The crosslinking of the gelatin matrix in the coated particles is started either by exposure to radiation or by an enzyme being present during incubation.

With respect to the beadlet compositions containing an enzyme, the crosslinking of the coated particles is carried out by incubating the enzyme at temperatures where the enzyme is stable, e.g., up to 40^oC. If appropriate, the enzymatically crosslinking procedure may be followed by treating as disclosed in U.S. Pat. No. 4,670,247. The enzymatic crosslinking process leads to less thermal stress of the active ingredient. Furthermore, the crosslinking reaction results in a homogeneously crosslinked product.

The crosslinking process induced by microwaves is carried out under stirring, usually in a microwave oven, e.g., at 1000 Watts for 10 minutes. The crosslinking process ensures uniform heating and prevents local overheating. Thus, the crosslinking reaction results in a homogeneously crosslinked product.

Claim 1 of 20 Claims

What is claimed is:

1. A process for preparing beadlets containing fat soluble substances comprising:

(a) forming an aqueous emulsion of a fat soluble substance, a gelatin, and a reducing agent;

(b) converting the emulsion into a dry powder; and

(c) crosslinking the gelatin matrix in the coated particles by exposing the coated particles to a radiation source.
 

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