NL1004294C2 - Method and means for inhibiting quality-reducing processes in foodstuffs. - Google Patents

Description

METHOD AND MEANS FOR BRAKING QUALITY-REDUCING PROCESSES IN FOODSTUFFS

The present invention relates to a method for counteracting or inhibiting quality-reducing processes in a foodstuff.

Foodstuffs such as vegetables, fruit, salads and milk products, such as butter, are subject to quality deterioration rather quickly, for example through the formation of so-called "off flavors", through browning, loss of nutritional value or texture changes. Today's consumer is becoming increasingly critical and sets 10 different requirements than before for the smell, color, taste, texture, appearance and shelf life of certain foods. For example, where green beans used to become relatively weak after processing (cooking or preservation), consumers now demand a product with more "bite". So-called non-natural additives, which were previously used regularly, are now also viewed with suspicion. The requirements for certain foods and their processing are therefore subject to extensive changes. This also requires adjustments in the production and processing of foodstuffs.

The changing production and processing of foodstuffs brings its own problems. Preserved green beans can again be taken as example 25. Shorter cooking times are required for a product with more "bite". The result, however, is that certain enzymes, which in the past were "boiled" as it were, now remain active, so that, in the case of green beans, for example, so-called "off flavors" are formed. Such "off flavors" are undesirable, but are irrevocably linked to the shorter cooking time.

Another example is the browning of fruit and vegetables such as mushrooms, apples and lettuce. Due to the changing lifestyle of the consumer, this requires 35 products, which have an increasing shelf life, but which also keep their appearance attractive and retain their smell and taste. However, this cannot be achieved without any form of processing.

A known problem with fats and fat-containing products such as butter is that they quickly become rancid. An adequate solution for this has still not been found.

The above problems have in common that they are caused in whole or in part by enzymes, and then generally by metal-containing enzymes. Well-known examples are lipoxygenase, which is among other things responsible for the formation of "off flavors" and is involved in the rancidity of fats, and polyphenol oxidase, which plays a role in browning. Peroxidases, which lead to the formation of free radicals, can also cause a deterioration in quality.

It is now the object of the present invention to provide a method and means for inhibiting or inhibiting such processes, which can moreover be regarded as "natural".

Surprisingly, it has now been found that casein is able to inhibit the activity of metal-containing enzymes.

Accordingly, the invention provides a method of counteracting or inhibiting quality-degrading processes in a foodstuff, comprising suitably using casein and / or a hydrolyzate and / or one or more fragments thereof as an inhibitor of metal-containing enzymes in the manufacture , 30 processing or preserving the food.

In addition to casein, hydrolysates or isolated casein fragments can also be used. Casein is a relatively large protein. Hydrolysates can be chemically or enzymatically manufactured. Chemical hydrolyzates consist of randomly cleaved casein, while in enzymatic hydrolysis casein is cleaved by proteases targeting particular sites. After hydrolysis, the casein fragments 1004294 3 formed in this way can be separated from each other. The fragments with the most inhibitory activity can be used separately or in combination.

In vegetables and fruits, the 5 enzymes to be inhibited are usually in the cells. When foodstuffs consisting mainly of intact cells are treated, complete casein will be much more difficult to penetrate into the cells in order to exert its inhibitory effect there. Therefore, in such cases, a hydrolyzate or casein fragments are advantageously used.

Casein is a mixture of phosphoproteins, which occurs naturally in, for example, milk and milk products and is therefore a "natural" agent. There are four subtypes, aSl, aS2, R and k. All casein subtypes are capable of inhibiting metal-containing enzymes, especially lipoxygenase. Furthermore, casein is heat stable, so that the activity is not lost through sterilization or pasteurization treatments.

The agent according to the invention therefore consists of pure casein, a hydrolyzate, individual fragments or combinations of one or more of these three. Optionally, the agent may be a composition comprising, in addition to the active ingredient, suitable excipients and / or additives. Such excipients or additives may, for example, be necessary to improve the membrane passage, further optimization of the inhibition process, increased solubility of the agent or improved emulsification of the agent.

The agent according to the invention can be added directly, for example in dry form or in solution, to the foodstuff and mixed through it, such as for example with salads. In canned foods, it can be added to the infusion (the moisture in a jar or can (sterilized) product).

In the following, the invention is illustrated by a number of examples.

Herein, lipoxygenase is used as a model enzyme. However, the 1004294 4 examples are not intended to limit the invention thereto.

EXAMPLES 5 EXAMPLE 1

In vitro inhibition of lipoxygenase by casein or casein hydrosolate

3.775 ml of 0.05 M Na2B407 buffer of pH 9 is placed in a reaction cell, together with 0.2 ml of 0.032 M linoleic acid 10 in 0.05 M Na2B407 buffer, pH 9. The solubility of linoleic acid in this substrate is improved by adding 0.25% (v / v) Tween 20. This is the control mixture. To prepare the reaction mixtures, part of the 3.775 ml buffer is replaced with a solution of, for example, 50 mg / ml casein in 0.05M Na2B407 buffer, pH 9, or a casein hydrolyzate, which is prepared as described in Example 2.

The table below shows the residual activity of the enzyme after inhibition with different types of casein.

20

Type of casein Residual activity of the enzyme (%) W-casein1 (10 mg / ml) 62.06 W-casein (50 mg / ml) 43.59 α-casein-P (10 mg / ml) 51.89 25 B- casein (50 mg / ml) 48.84 β-casein-P (10 mg / ml) 63.77 κ-casein (10 mg / ml) 42.12

Esprion ™ 580 hydrolyzate2 (50 mg / ml) 33.85

Esprion ™ 3 00 hydrolyzate2 50 mg / ml 50.06 30 whole-casein (mixture of the 4 subtypes of casein in the proportion as they exist in milk 2 hydrolyzate of a whey protein isolate 1004294 5

As can be seen from the above data, in reaction mixtures to which casein or a hydrolyzate thereof has been added, the enzyme activity is markedly less, indicating an inhibitory effect of the casein or casein hydrolyzate.

EXAMPLE 2

Manufacture of hydrolysates

Casein hydrolysates are prepared by adding a protease or a mixture of proteases as a solution to a solution of casein in a buffer suitable for the protease (s) used. The reaction is carried out, for example, by stirring for about 24 hours.

For example, 2.5 g of casein can be suspended with stirring in 95 ml of 0.1 N HCl at 37 ° C. After 20 minutes, the pH is adjusted to 1.9 using 1 N NaOH. Pepsin (5000 units / mg casein) is then dissolved in 5 ml 0.1 N HCl and added to the reaction mixture. 2 ml samples are taken on a regular basis. Of these, the pH is adjusted to 7.5 with 1 N NaOH, whereby the reaction is stopped. The degree of fragmentation is determined by HPLC. If a satisfactory result is obtained, the pH of the entire reaction mixture is adjusted to 7.5 with 1 N NaOH. (See also S.F. Gauthier, C. Vachon and L. Savoie, Journal of Food Science 51 (4), 962 (1986)). Then, if desired, the mixture can be separated into the resulting fragments, each of which can be individually tested for oxygenase inhibitory activity.

1004294

Claims (7)

A method for counteracting or inhibiting quality-reducing processes in a foodstuff, comprising suitably using casein and / or a hydrolyzate and / or one or more fragments thereof as an inhibitor of metal-containing enzymes in the manufacture, processing or food preservation. 2. A method according to claim 1, characterized in that the metal-containing enzyme is lipoxygenase, polyphenol oxidase, or peroxidase. Process according to claim 1 or 2, characterized in that the hydrolyzate is obtained by chemical and / or enzymatic hydrolysis of casein or a casein-containing product. Method according to claim 1, 2 or 3, characterized in that the foodstuff consists of vegetables, fruit, salads or milk products. A method according to any one of claims 1-4, characterized in that the quality-reducing processes consist of the development of "off flavors", texture changes, browning or loss of nutritional value. 6. Casein and / or a hydrolyzate and / or fragments thereof for use as an agent for inhibiting or inhibiting quality-reducing processes in foods. 7. Means for inhibiting or inhibiting quality-reducing processes in foods, including casein and / or a hydrolyzate and / or fragments thereof. 1004294