DK163100B - PROCEDURE FOR THE PREPARATION OF A PLANT FIBER PRODUCT AND USING THE PLANT FIBER PRODUCT AS A SUBSTANCE OF FOOD AND FOOD PRODUCTS - Google Patents

Description

DK 163100 B

The invention relates to a process for the production of a plant fiber product, suitable as a constituent in food and beverage products, in particular in bread and other bakery products.

5 · Over the last decade, there has been a steadily increasing desire among consumers to increase the diet's content of so-called dietary fiber, ie. fibers which do not break down as they pass through the digestive tract.

Too little intake of dietary fiber 10 is believed to increase the risk of certain serious diseases, such as colon cancer and circulatory disease. In addition, consuming an increased amount of dietary fiber as a substitute for caloric nutrients is appropriate and usual when calorie intake is desired to be reduced.

15 This desire to increase the diet's content of indigestible fiber has led some consumers to change their diets towards consuming a larger proportion of vegetables and more coarsely ground cereal products, such as bran.

20 However, it is a desire of many consumers that the increased intake of dietary fiber should be done without changing the diets and while consuming foods and pleasures that do not differ significantly from those of the relatives.

25 This means that there is a need for products which can be used as dietary fiber enriching ingredients in the manufacture of foods and pleasures without significantly affecting their taste, appearance and other properties.

For a fiber product for the aforementioned use, compliance with, among other things, the following conditions is required or desirable: 35 2

DK 163100 B

a) Physiologically acceptable composition, which implies that both the chemical composition determined by the origin of the fibers is acceptable and that the product has not been contaminated or transformed in physiologically disadvantageous upon processing.

b) Organoleptically satisfactory properties, including a neutral taste or preferably no taste at all, and the ability not to significantly alter what is termed "mouth feel" of foods and pleasures in which the fiber product is used.

(C) Suitable water and fat absorption properties, such as are necessary for the fiber product to replace flour or other usual components without significantly altering the nature of the finished foods and foods, or without the methods of preparation of the foods and foods concerned must be changed substantially as a result of the use of the fiber product.

These absorption properties also affect the mouth feel mentioned in (b).

25 d) Pure white color so that the exchange of white flour with the fiber product, e.g. when baking, do not cause any color changes to the finished foods and pleasures.

E) The material used as the starting material for the manufacture of the fiber products should preferably be one which is usually associated with foodstuffs and which is therefore not regarded by consumers as conceivable or forward-looking as a component of nutritional and enjoyment 3

DK 163100 B

agents.

Among the known fiber products for that purpose, there is nothing that fully satisfies the above conditions.

Among materials proposed for this purpose, cellulose fibers are derived from wood, especially hardwood. However, wood cellulose fibers can only be used in relatively small quantities without changing the nature of the nutritional or nutritional agents, especially with regard to the mouth feel mentioned above in (b). To counteract this, it has been proposed to combine the use of wood cellulose products with various consistency regulators and stabilizers, but such use of excipients, which are not usually included in food and enjoyment agents of that kind, is undesirable.

In addition, the fact that wood cellulose does not meet condition e) above.

U.S. Patent No. 4,307,121 discloses a process for producing a cellulosic fiber product suitable for human consumption from soybean shells, pea pods, corn shells or beet pulp. The work-up includes, inter alia, bleaching with Cl2, which gives the presumption that the product may contain greater amounts of chlorinated organic compounds than is considered acceptable in foodstuffs.

According to the patent, the method cannot in practice be applied to the stem parts of plants.

30 U.S. Patent No. 4,774,098 discloses the preparation of a fiber product for use in foodstuffs by delignifying a non-woody lignocellulosic substrate by treatment with hydrogen peroxide at a pH between 11.2 and 11.8. Examples of ligno-cellulose substrates include wheat straw.

Typically, between 40 and 60% of the substrate origin is removed.

DK 163100B

4 equal lignin content. However, a straw made of fiber in which only such a small proportion of the original lignin content is removed will hardly be able to meet the above conditions, as the lignin prevents the product from assuming a pure white color and the lignin further causes that the material will impart a somewhat "woody" taste and "mouth feel" to the nutrients in which it is incorporated.

Finally, published Danish Patent Application No. 997/85 mentions the possibility of producing a product, suitable as dietary fiber, by enzyme processing of straw. The conditions for carrying out this treatment are not disclosed, but it must be assumed that this is also a product which is only partially delignified. That the 15 product cannot be white seems obvious.

It has now been found that a plant fiber product which, to a greater extent than any of the known dietary fiber products, satisfies the above conditions a) -e) can be prepared from straw using a combination of a number of per se known treatments, as defined below, when the treatments are performed with such efficacy that virtually all lignin is removed.

Accordingly, the process of the invention is characterized in that, after mechanical cutting and purification, cereal straw is subjected to the following treatments in the following order: ) treatment with C102 in acidic medium, (iii) treatment with H2O2 in basic medium, (iv) treatment with ClO2 in acidic medium, and (v) drying and milling, 5

DK 163100 B

the treatments (i) - (v) being carried out with such duration and intensity that substantially all lignin is removed and the finished fiber product obtained with a whiteness greater than 80 by Iso standard.

The resulting plant fiber product meets all five conditions a) -e).

By carrying out the delignification to such an extent that the fiber product is obtained with a whiteness greater than 80 according to the Iso standard, the risk is reduced that the final product will contain undesirable organic chlorine compounds such as chlorinated phenols, since the risk of forming them is substantially higher in cases , where the final product still contains significant amounts of lignin, which is known to be made up of phenolic compounds.

15 Thus, introducing the whiteness of the product as a measure of the processing intensity to be achieved serves not only to ensure that the final product can be used without discolouring the food and enjoyment agents in which it uses, but equally to ensure, 20 that the product does not contain any health-related components, created during the treatments with C102.

In addition, the extensive lignin removal reflected in the great whiteness is desirable for the organoleptic properties of the material as explained above.

Treatment with C102, all else being equal, gives rise to a substantially smaller amount of chlorinated organic compounds than a corresponding treatment with Cl2, while in combination with the other measures it ensures an effective removal of the components of the straw which is not cellulose or hemicellulose (pentosans).

Thus, it is an essential feature of the invention that, in part, to achieve the very far-reaching removal of the components which are not cellulose or

DK 163100 B

6 hemicellulose, and thus the removal of potential base materials to form the undesirable chlorinated compounds, and partly to use a treatment which in itself has little tendency to form health-damaging compounds, achieves a final product which can be used without concern human consumption.

The material prepared according to the invention has been subjected to extensive analyzes. Among these, there is a particular interest in tetrachloro-10β-dibenzo-dioxins and furans, which are often summarized under the name "dioxins" and which are feared because of their high toxicity.

These analyzes showed that the compounds 2,3,7,8-tetrachloro-p-dibenzo-dioxip and the corresponding furan compound were present in such small quantities that they could not be detected while the total content of tetrachloro-di-benzo -dioxins were determined at 0.545 dpi (part per trillion) and the total content of tetrachloro-p-dibenzo-fuane was determined at 0.324 dpi.

A content of up to 20 ppt of these compounds will usually be considered acceptable.

By HPLC analysis, presence of chlorinated phenols could not be detected.

Analysis of a typical product made from 25 wheat straw using the method of the invention yielded the following results:

Ash 1.34% calculated on dry matter

Cellulose content 72.1% based on dry matter 30 Pentosan content 25.7% based on dry matter

Kappatal less than 1.

From this it can be calculated that the lignin content is less than 0.15%, based on dry matter.

35 The above determination of the pentosan content we see that this is substantially greater than what applies 7

DK 163100B

for cellulose derived from wood. This greater pentosan content is associated with the improved water absorption and taste properties of the material produced by the process of the invention compared to cellulose based on wood.

A preferred embodiment of the process is characterized in that wheat straw is used as cereal straw, since a resulting product is easily accepted by the consumer as a constituent of food and nutrients, which is otherwise based on wheat flour, and since the process according to the invention is especially proven in connection with wheat straw.

The product resulting from the process appears as a white powder which may be negotiated as such or which may be suitably negotiated admixed with other components used e.g. by baking. Thus, the invention also relates to a flour-containing mixture, in particular for use in the preparation of white bread types, which is characterized in that it contains, in addition to flour and the usual auxiliaries, a plant fiber product prepared according to the process according to the invention.

The invention is further illustrated by the following Example: 25

Example

The process was carried out using an industrial plant developed to produce cellulose for paper fabrication.

Wheat straw, after cutting lengths of a few cm, was sorted to remove grains and dust, and then combined with a sodium hydroxide-based boiling liquor, but without the sulfite or sulfate constituents common in many cellulose preparation processes.

Claims (6)

0 DK 163100B The straw and lye mixture was cooked at approx. 160. for 2.5 hours, and the now substantially disintegrated fiber mass was subjected to countercurrent washing and vibration sieving to remove undissolved 5 particles and impurities. The resulting fiber suspension was pumped through a sand removal hydrocyclone system and then transferred into a so-called bleaching tower, where the pH was adjusted to approx. 3.5 with sulfuric acid, and then C102 was added to the bottom of the bleaching tower. The temperature during this treatment step was approx. 45 C and the treatment time approx. 1 hour. Then, the pulp was washed out and suspended in an aqueous NaOH solution to which H 2 O 2 was added. During this treatment step, the pH value was approx. 11.0 the temperature was approx. 70 C, and the duration of treatment 1.5 hours. The fiber pulp was again leached and then re-treated with C102 in acidic medium under the same conditions as used in the first 0 ClO 4 hours. After washing, the pulp was dewatered to form a pulp web which was dried and ground to a fiber powder. This fiber powder had a whiteness of 83, determined by Iso standard. In baking tests, this fiber powder was found to be able to replace up to 50% by weight of the wheat flour in white bread without the finished bread being distinguishable from bread 30 without the addition of fiber product. This applies both in appearance, taste and mouth feel. 1. A process for the preparation of a plant-fiber product suitable as a constituent in food and beverages, in particular in bread and other bakery products, characterized in that cereal straw after mechanical cutting and purification is subjected to the following treatments in the following order: 5 (i) boiling in sodium hydroxide-containing liquor without sulphate or sulphite addition at atmospheric pressure, (ii) treatment with C102 in acidic medium, (iii) treatment with C202 in basic medium, (iv). treatment with C102 in acidic medium and 10 (v) drying and grinding, the treatments (i) - (iv) being carried out with such duration and intensity as to remove substantially the lignin and obtain the finished fiber product with a white-15 was greater than 80 by Iso standard. Process according to claim 1, characterized in that wheat straw is used as cereal straw. Use of a fiber product made according to claim 1 or 2 as a constituent of food and enjoyment agents. Use according to claim 3, characterized in that the fibers are incorporated into a dough for making white bread. A flour-containing mixture, in particular for use in the preparation of white bread types, characterized in that it contains, in addition to flour and the usual auxiliaries, a plant fiber product prepared according to the process according to claim 1 or 2. 6. Bakery product, especially white bread, is characterized by the fact that it is made from a dough which differs from conventional dough in that from 5-50% by weight of the flour which will be incorporated into the dough in traditional manufacture. replaced by a plant fiber product produced by the method of claim 1 or 2.