Cake-resistant, hygroscopically sensitive materials and process for producing the same

This application claims the benefit of U.S. provisional application No. 60/069,707, filed Dec. 16, 1997.

1. Field of the Invention

The present invention relates to cake-resistant products which comprises materials which are normally hygroscopically sensitive. The present invention also relates to a process for preparing such materials.

2. Discussion of the Background

Dried, flowable food ingredients such as hydrolyzed vegetable proteins, autolyzed yeast extracts, and tomato powders have long been used in the food industry for their contribution to flavor in finished products. However, these products tend to be extremely sensitive to ambient humidity. As a result, such products tend to absorb moisture and cake. They also tend to absorb moisture when combined with components with a higher moisture content, which can also lead to caking.

Caking is a problem, because it impairs the flowability of the product, which leads to production problems. The caking of such products tends not to be reversible and, thus, renders the products unusable.

Suppliers of these ingredients have attempted to alleviate the problem of caking by adding an edible oil such as cottonseed oil or other vegetable oil or a polyoxyethylene sorbitan monoester to the products to reduce the propensity of the product to absorb moisture.

However, such oil-containing products still tend to cake when exposed to high humidity conditions.

U.K. 1,538,958 discloses the addition of silica and an edible oil to hydrolyzed protein to prepare a dust-free and free-flowing product. However, the addition of oil is undesirable, because non-water-soluble components can contribute oxidative off flavors, increase caloric intensity, and cause oiling off of the product in the final application.

Thus, there remains a need for products which contain a hygroscopically sensitive material but are resistant to caking. There also remains a need for a process for preparing such a product.

Accordingly, it is one object of the present invention to provide a product which comprises a hygroscopically sensitive material but exhibits a high resistance to caking.

It is another object of the present invention to provide a product which comprises a hygroscopically sensitive material but exhibits a high resistance to caking when exposed to high humidity conditions.

It is another object of the present invention to provide a product which comprises a hygroscopically sensitive food ingredient but exhibits a high resistance to caking when exposed to high humidity conditions.

It is another object of the present invention to provide a product which comprises a hydrolyzed vegetable protein but exhibits a high resistance to caking when exposed to high humidity conditions.

It is another object of the present invention to provide a process for producing such a product.

These and other objects, which will become apparent during the following detailed description, have been achieved by the inventors' discovery that the hygroscopic nature of many food ingredients, such as hydrolyzed vegetable proteins, is due in large part to the presence of fine particles (i.e., particles with small average particle size) in the material. The presence of fine particles in such materials is, in turn, the result of the manufacturing processes used to prepare such materials. Food ingredients such as hydrolyzed vegetable proteins are typically prepared by spray drying which results in the material containing very small particles (e.g., average particle size of 30 to 150 microns). Thus, the inventors have discovered that it is possible to reduce a normally hygroscopically sensitive material's tendency to cake in the presence of high humidity conditions by mixing with a carrier material and increasing the average minimum dimension of the material to at least 125 to 2,000 microns, preferably 250 to 1,200 microns.

Thus, in a first embodiment, the present invention provides a product which comprises a material which is hygroscopically sensitive and a carrier material and has an average minimum dimension of 125 to 2,000 microns, preferably 250 to 1,200 microns.

In a preferred embodiment, the average minimum dimension of the product comprising a hygroscopically sensitive material and a carrier is increased by milling an extruded product. Thus, the present invention also provides a process for producing a product which contains a hygroscopically sensitive material but is resistant to caking, comprising:

(i) forming a melt comprising a hygroscopically sensitive material and a carrier;

(ii) extruding the melt, to obtain an extruded product;

(iii) milling the extruded product to obtain a milled product with an average minimum dimension of 125 to 2,000 microns, preferably 250 to 1,200 microns.

Alternative methods for increasing the average minimum dimension of the hygroscopically sensitive material include pressure compaction, granulation, and fat agglomeration.

Thus, in a first embodiment, the present invention provides products which comprises a hygroscopically sensitive material and a carrier material but are resistant to caking. Preferably, the hygroscopically sensitive material is a food ingredient.

Examples of hygroscopically sensitive food ingredients which may be included in the present products include hydrolyzed vegetable proteins, such as hydrolyzed soy protein, hydrolyzed corn protein, and hydrolyzed wheat protein; spray-dried soy sauce; tomato powder; onion powder; garlic powder; other natural vegetable powders which are high in carbohydrates; autolyzed yeast extracts; and spray-dried syrups. Most preferably, the hygroscopically sensitive material is a hydrolyzed vegetable protein.

Within the context of the present invention, a material is hygroscopically sensitive if it absorbs and retains moisture under defined relative humidity and temperature conditions, such as 75% relative humidity at 90° F.

The present product comprising the hygroscopically sensitive material and carrier material has an average minimum dimension of 125 to 2,000 microns, preferably 250 to 1,200 microns, more preferably 400 to 1,200 microns. The average minimum dimension may be measured using Official ASTA Analytical Method 10.0, American Spice Trade Association Official Methods, 1997, Englewood Cliffs, N.J. 07632.

In a preferred embodiment, the present product may further comprise additional components such as a flow agent such as calcium stearate and silica (including micronized silicon dioxide, sodium silicate,: potassium silicate, and sodium silicoaluminate-treated (hydrophobized) silica).

Typically, the present product will comprise the hygroscopically sensitive material in an amount of 50 to 99.9% by weight, preferably 80 to 99% by weight, more preferably 80 to 95% by weight, based on the total weight of the product. When the present product contains a flow agent, the flow agent will typically be present in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.1 to 2% by weight, based on the total weight of the product.

Typically the product comprises from 0.1 to 50 weight %, preferably from 1 to 20 weight %, more preferably from 5 to 10 weight %, of the carrier material, based on the total weight of the product.

The cake-resistant product according to the present invention offers retained flowability under conditions where caking typically occur. Flowability is the ability of a powder or particulate to move in mass under a defined application of force.

Certain methods for preparing the present product, including milling of an extruded product, employ a carrier material, such as a proteinaceous or sugar type carrier. Mixtures of carrier materials are provided for. Examples of suitable carrier materials include any viscosity building agent, e.g., modified and native maltodextrins of corn, wheat, potato, barley, paselli, and other grains such as, PRIMACEL™, i.e. microfibrous cellulose, wheat gluten and lactose; structural proteins such as gelatin; modified and native starches of corn, wheat, potato, barley, and other grains; gums and exudates such as tragacanth, xanthan, algin, carrageenan, ghatti, arabic, and pectins. Preferred carrier materials are gum arabic, paselli maltodextrin, primacel cellulose and a mixture thereof.

In a preferred embodiment, the cake-resistant product does not contain an edible oil such as cotton seed oil, vegetable oil, or a polyethylene sorbitan monoester. In this context, the cake-resistant product is considered not to contain an edible oil if the content of edible oil is ≦10 wt. %, preferably ≦5 wt. %, more preferably ≦1 wt. %, even more preferably ≦0.5 wt. % and even more preferably ≦0.1 wt. % and even more preferably 0 wt. %.

In another embodiment, the present invention provides a method of reducing the tendency of a hygroscopically sensitive material to cake by increasing the average minimum dimension of the hygroscopically sensitive material to 125 to 2,000 microns, preferably 250 to 1,200 microns, more preferably 400 to 1,200 microns. Typically, the starting material used in the process for producing the present product will be a hygroscopically sensitive material which has been produced by spray drying and, thus, has an average particle size of 30 to 150.

Any method of increasing:the average minimum dimension of the hygroscopically sensitive material and carrier material may be used so long as the method does not have a deleterious effect on the hygroscopically sensitive material. Specific examples of methods which may be used to increase the average minimum dimension of the hygroscopically sensitive material include milling an extruded product, pressure compaction, granulation, and fat agglomeration.

In a preferred embodiment, the present product is prepared by a process comprising:

(i) forming a melt comprising a hygroscopically sensitive material and a carrier material;

(ii) extruding the melt, to obtain an extruded product;

(iii) milling the extruded product to obtain a milled product with an average minimum dimension of 125 to 2,000 microns, preferably 250 to 1,200 microns.

The formation of products by melt extrusion is described in detail in, e.g., U.S. Pat. Nos. 5,601,865; 5,603,971; 5,792,505; 5,897,897; and 6,090,419, all of which are incorporated herein by reference in their entirety.

Examples of the carrier material to be used in the present process are the same as those described above in the context of the present product. Typically the melt comprises from 50 to 99.9 weight %, preferably from 80 to 99 weight %, more preferably from 90 to 95 weight %, of the hygroscopically sensitive material and from 0.1 to 50 weight %, preferably from 1 to 20 weight %, more preferably from 5 to 10 weight %, of the carrier material, based on the total weight of the melt.

The milling of the extruded product may be carried out by means of any suitable device. Examples of suitable devices for milling the extruded product include hammer mills, roller mills, and rotary mills.

In a particularly preferred embodiment, the milled product is coated with a flow agent. Suitable flow agents are the same as those listed above in the context of the present product. The milled agent may be coated with the flow agent by means of any suitable device. Examples of suitable devices for coating the milled product with the flow agent include rotary drums and ribbon blenders. Alternatively, the flow agent can be added during sieving of the milled product. Typically, the milled product will be coated with the flow agent in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.1 to 2% by weight, based on the total weight of the milled product and the flow agent.

The present product will typically be stored and shipped in a moisture-proof package. An example of a typical package is a 4 mil polyethylene-lined kraft paper bag or a polyethylene bag contained in a cardboard box.

Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.