Use of a pyrodextrin hydrolysate for the preparation of a food composition for performing improvement of serum lipid

Abstract: A food composite for performing improvement of serum lipid comprising a refined product of pyrodextrin obtained as an active ingredient through a process of decomposing starch or starch hydrolyzate by heating in the presence of an acid or without acid.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention: The present invention relates to the use of a pyrodextrin hydrolysate for the preparation of a food composition capable of performing a function of improving serum lipid. In the invention, the term "function of improving serum lipid" means: (1) a function of reducing serum lipid and total cholesterol in serum; and (2) a function of improving serum lipo-protein metabolism. 2. Description of Prior Art: Increase in serum lipid and cholesterol in serum and decrease in relative content of HDL-cholesterol called benignant cholesterol can be said malignant factors of various circulatory diseases such as arteriosclerosis, cerebral infraction or adult diseases such as obesity, diabetes or the like. It is a recent trend also in Japan that the rate of occurrence of the mentioned diseases has sharply increased with the westernization in meal. The invention intends to provide a food composition performing the function of decreasing serum lipid and cholesterol in serum while increasing the relative content of HDL-cholesterol. Hitherto, dietary fibers have been well known as material performing the fucntion of decreasing the mentioned serum lipid, etc. Generally, dietary fibers are divided into water-soluble dieatary fibers and insoluble ones, and their typical physiological functions have been reported as follows: (1) function of reducing cholesterol in serum and liver; (2) function of saving increase of blood glucose; (3) function of regulating large bowel; and the like. With respect to the above function (1), Among those functions, it is generally said that this function (1) is effective for preventing various disorders caused by negative relation between intestinal flora and metabolite, abdominal inflation, restraint of absorbing nutritious material, inhibition of circulation through bowel and liver and so on. It is also said, however, that in case of these dietary fibers, the insoluble fibers represented by cellulose have a disadvantage in view of taste and texture, and that, though the soluble fibers represented by guar gum and pectin is certainly advantageous in view of performing such useful phisiological function of saving increase of blood glucose and inhibition of cholesterol, they also have a disadvantage of giving negative affect on absorption of useful metals. Moreover, because of high viscosity, there arises a further disadvantage of making it difficult to take them in a large quantity and, as a result, uses of these fibres are quite limited. As noted above, westernization and diversification of meals have taken place also in Japan and the mentioned diseases have been increasing. The inventors of the present application have noticed the existence of pyrodextrin that has never been considered as food material and, after having repeated studies and tests on whether or not pyrodextrin exhibits the performance of serum lipid, come to reach a new idea of developing a novel food composition capable of performing such function of improving serum lipid. EP-A-0443788 and EP-A-0443789, both published on 28-08-91 and having priority dates of 22-02-90 and 20-02-90 respectively relate to food compositions comprising a refined product of pyrodextrin obtained as an active ingredient through a process of decomposing starch or starch hydrolysate by heating in the presence of an acid or without acid. The food composition described in EP-A-0443788 is for use in saving insulin secretion whereas the composition of EP-A-0443789 regulates the larger bowel. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to develop and provide a novel food composition being capable of performing a function of improving serum lipid from pydrodextrin based on the mentioned new idea. The foregoing object of the invention is accomplished by employing a refined product of pyrodextrin that can be obtained through a process wherein starch or starch hydrolysate is decomposed by heating in the presence of an acid or without an acid, the mentioned refined pyrodextrin serving as a main composition of food composition performing a function of improving serum lipid. As mentioned above, the invention is based on a novel concept that the refined pyrodextrin obtained through the process of decomposing at least one of starch or starch hydrolyzate exhibits an extremely remarkable function of improving serum lipid, more specifically, the mentioned functions of (1) and (2). Described now is a process for preparing pyrodextrin in accordance with the invention. As for a raw starch, that is, a starch to be employed in embodying the invention, a wide range of starches such as potato, corn, and cassaba can be utilized. It is also preferable to employ those starches in the form of processed food commertially available in the market. In this case, enumerated as processed starches are, for example, soluble starch, esterified starch, etherized starch, cross linked starch and, preferably, starch phosphate and hydroxypropyl starch. Furthermore, as a material employed in embodying the invention, starch hydrolyzate is used other than the starches mentioned above. This starch hydrolyzate is obtained by slightly hydrolyzing a starch, and in such hydrolyzation, acid or enzyme may be added. The degree of hydrolyzation of starch should be in the range of DE3 to DE4, and the added acid should be normally oxalic acid or hydrochloric acid with their amount in the range of 0.01% to 0.1% (in terms of the weight of starch). In addition, α-amylase can be used as enzyme. These raw materials in accordance with the invention are decomposed by heating, preferably, under normal pressure. The decomposition by heating is achieved by heating the materials at a temperature from about 150°C to 220°C for 1 to 5 hours. The pressure at the heating may be the normal one without necessity of either vacuum or pressure. At this heating step, it is also preferable to add an acid as a catalyst for heating decomposition. As the acid to be adopted as the catalyst, mineral acids such as sulfuric acid hydrochloric acid and nitric acid can be used, and in particular, hydrochloric acid is preferable when added in an amount of several % by weight to the materials to have a concentration of 1% by weight. The acid should be added evenly, being, preferably, well mixed by spraying. The mixture is then preferably dried up preliminarily at a temperature from about 100°C to 120°C so as to reduce the moisture to about 5%. The dextrin in accordance with the invention obtained in the mentioned process, that is, pyrodextrin is then subject to refining. The refining process is now described hereunder: At least one treatment of following (a) and (b) are employed: (a) After a hydrolysis with α-amylase, or after a hydrolysis with glucoamylase following the hydrolysis with α-amylase, the solution is refined through known processes of filtration, decolorization, and deionization. (b) After completing of the treatment (a), a further treatment separates dextrin fraction with chromatography by ion-exchanger resins. Further description on the treatments (a) and (b) is given in detail as follows: In the treatment (a), pyrodextrins are dissolved in water to obtain a solution of 30% to 50% by weight, and then neutralized to pH5.5 to 6.5, preferably to pH5.8, and 0.05% to 0.2% by weight of α-amylase (available in the market, either the one originated from mold and the one from bacteria may be applied) based on the pyrodextrin is added to the solution, and then at the reaction temperature of said amylase in the range from about 85°C to 100°C, the solution is hold for 30 minutes to 2 hours. Subsequently, the temperature of the solution is raised up to 120°C to complete the reaction of α-amylase. Thereafter, the temperature of the solution is decreased to about 55°C, and the solution is adjusted to about pH5.5, then 0.05% to 0.2% by weight of glucoamylase (popularly used) based on the original dextrin is added. The solution is kept at a temperature to allow its reaction for 24 to 48 hours. This reaction aims at decomposition of small molecules such as oligosaccharides into glucose. Following this step, temperature of the solution is raised up to, for example, about 80°C to complete the reaction of glucoamylase. On the other hand, in the treatment (b), chromatographic separation by ion-exchanger resin is carried out. In this treatment, strongly acidic cation exchanger resins sold widely on the market can be employed. Preferable as concrete examples are Amberlite IR-116, IR-118, IR-120B, XT-1022E, XT-471F (all manufactured by Organo), Diaion SK-1B, SK-102, SK-104, SK-106, SK-110, SK-112, SK-116, FR-01 (all manufactured by Mitsubishi Chemicals), and XFS-43281.00, XFS-43280.00, XFS-43279.00, XFS-43278.00 (all manufactured by Daw Chemicals). These resins are preferably dealt with as alkaline metal type or alkaline earth metal type before their uses. It is preferable to adjust the rate of flow at the time of a column fluid according to a resin to be used. The rate of flow of the fluid is preferably in the range of SV = 0.1 to 0.6. The rate of flow out of the above range is tend to deteriorate the workability and separation. The temperature at the time of running the fluid is preferably in the range from 20°C to 70°C, and a temperature below this range will deteriorate the separation and make the viscosity of fluid get high, thereby giving a negative influence on the fluid, while a temperature exceeding this range will cause the fluid to be colored and deteriorate other quality characteristics. When observing carefully the dextrin refined from the mentioned pyrodextrin, it was recognized that their linkages were not only 1 → 4 and 1 → 6 bonds with glucose as structural sugar, but also 1 → 2 and 1 → 3 bonds. Further, a part of reducing end group is of 1-6-anhydroglucose. Viscosity of this pyrodextrin is rather low, i.e., about 10cps (30%, 30°C), and it tastes slightly sweet and is orderless, with the number of 1 → 2 and 1 → 3 bonds below about 10%. The pyrodextrin is, therefore, easily employed as a material for various beverages and processed foods and, furtherfore, it is as safe to be eaten as maltodextrin since its raw material is starch. In this manner, the pyrodextrin serving as the above food material in accordance with the invention can be widely used as a material for various foods, and its uses extend to any food so far as it is used as a material for food. Typical foods in this sense are, for example, beverages, desserts and candies. Other objects, features and advantages of the invention will become apparent in the course of the following description accompanied by the drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 to 7 are graphs showing the results of measuring the function of improving serum lipid on the food composition; and wherein, Figure 1 shows transition of accumulated intake amount of water; Figure 2 shows transition of weight; Figure 3 shows transition of total protein; Figure 4 shows transition of calcium; Figure 5 shows transition of triglyceride; Figure 6 shows transition of total cholesterol (solid line) and HDL-colesterol (dot line); and Figure 7 shows transition of HDL-cholesterol division. Throughout the drawings, marks indicate respectively as follows:  : control ○ : PF-C ▴ : PF DESCRIPTION OF THE PREFERRED EMBODIMENTS Several examples in accordance with the present invention is hereinafter described in more detail. Example 1 : 5-week-old male rats of SD strain (JAPAN CLEA) were put in separate cages and raised preliminarily for 10 days with ordinary solid feed. These rats were divided into three groups each being formed of 5 rats, then three kinds of solution, i.e., an aqueous solution of 10% PF, an aqueous solution of 10% PF-C and tap water were respectively given from feeding bottles to them as drinking water. The three groups of sample rats were free to take the feed and water in, and during the period from one week before starting this test until passing seven weeks therefrom, their intake amount of water, weight, total protein in blood, calcium, triglyceride, total cholesterol and HDL-cholesterol were periodically measured in the following methods, respectively: Total protein in blood by buret method Calcium OCPC method Triglyceride enzyme method Total cholesterol enzyme method Total HDL-cholesterol enzyme method Figures 1 to 7 shows the results of measurement, and in which each drawing, PF, and PF-C show the followings, respectively: Figure 1: transition of accumulated intake amount of water; Figure 2: transition of weight; Figure 3: transition of total protein; Figure 4: transition of calcium; Figure 5: transition of triglyceride; Figure 6: transition of total cholesterol (solid line) and HDL-colesterol (dot line); and Figure 7: transition of HDL-cholesterol division. Throughout the above drawings, average value ± standard error ( x ≐SEM) marks indicate respectively as follows:  : control ○ : PF-C ▴ : PF * : p < 0.05 (showing a significant peril rate of 5% with respect to the comparative reference by T test) * : p < 0.02 (showing a significant peril rate of 2% in the same test) PF : a substance obtained by a process wherein pyrodextrin is hydrolyzed with α-amylase, then is refined by decolorization with activated charcoal and deionization using ion exchager resins. PF-C : a substance obtained by a process wherein pyrodextrin is hydrolyzed with α-amylase and glucoamylase, then the glucose produced thereby is excluded by column chromatography. It is understood from Figure 1 that there was no difference among the three groups of sample rats in the aspect of accumulated intake amount of water, and PF and PF-C were taken in without trouble. It is understood from Figures 2 to 4 that there was no difference among the three groups of sample rats in the aspect of weight, total protein in blood and calcium values, and thus it was acknowledged that neither PF nor PF-C gave negative influence on the growth of rat and absorption of mineral to be taken in safely. It is understood from Figure 5 that triglyceride value of the sample rats belonging to the PF and PF-C intake group was definitely small as compared with the control group, and this advantage has been recognized throughout the entire period of test. It is understood from Figure 6 that total cholesterol value has shown a reduction corresponding to the growth of the sample rats belonging to the control group up to the second week, then normal state has been kept up to the seventh week. On the other hand, total cholesterol value in the PF and PF-C gruop has shown a sharp reduction up to the second week from the beginning of the test, and has further continued to reduce up to the fifth week. The total cholesterol values up to the fifth and seventh weeks were both significantly low as compared with the control group. Concerning the HDL-cholesterol value deeply involved in the prevention of arteriosclerosis and ischemic heart disease, no difference was acknowledged among the three groups. It is, however, understood from Figure 7 that when calculating percentage of HDL-cholesterol occupied in total cholesterol, the PF and PF-C group shows high percentage as compared with the control group, and an advantage of improvement in lipoprotein metabolism was recognized. In this respect, it was reported by S.R. Srinivasan and others that when giving a meal of low saturation fat to resus monkeys, etc., their serum cholesterol level is lowered as compared with a meal of dextrin in substitution for cane sugar. It has been heretofore well known that serum cholesterol level goes down easily by reducing intake energy. On the other hand, cane sugar, in particular fructose being a main component thereof performs a function of increasing cholesterol and neutral fat. Accordingly, in the mentioned well-known method for cholesterol reduction, influence by cane sugar should not be ignored in spite of energetic equivalency. Consequently, in the foregoing embodiment in accordance with the present invention, solid feed commercially available in the market was given to every group of control and sample rats, and indigestible dextrin was dosed to the samples as drinking water in substitution for tap water in order to verify influence on the serum cholesterol and other clinical test values.

Claims: The use of a pyrodextrin hydrolysate for the preparation of a food composition for decreasing the lipid content and total cholesterol in serum and increasing the relative HDL cholesterol content in serum, wherein said hydrolysate is obtained by heating starch in the presence of hydrochloric acid in an amount of 0.01 to 0.1% by weight based on the weight of said starch at 150°C to 220°C for 1 to 5 hours to prepare pyrodextrin; dissolving the pyrodextrin in water to form an aqueous solution in an amount of 30 to 50% by weight of pyrodextrin based on the weight of the solution; adjusting the pH of the solution to pH 5.5 to 6.5; treating the solution with alpha-amylase in an amount of 0.05 to 0.2% by weight based on the weight of the pyrodextrin at 85°C to 100°C for 0.5 to 2 hours; treating the solution with glucoamylase in an amount of 0.05 to 0.2% by weight based on the weight of the pyrodextrin at about 55°C for 24 to 48 hours; and refining the hydrolyzed pyrodextrin. The use of a pyrodextrin hydrolysate as claimed in claim 1, wherein said pyrodextrin hydrolysate contains 1 → 4, 1 → 6, 1 → 2 and 1 → 3 glucosidic linkages and a part of reducing terminal groups of said pyrodextrin hydrolyase are 1 - 6-anhydroglucose. The use of a pyrodextrin hydrolysate as claimed in claim 1, wherein the hydrolyzed and refined pyrodextrin is further subjected to ion exchange resin chromatography to separate said pyrodextrin hydrolysate.

Inventors: OHKUMA KAZUHIRO, SATOUCHI MITSUKO, WAKABAYASHI SHIGERU, OHKUMA, KAZUHIRO, SATOUCHI, MITSUKO, WAKABAYASHI, SHIGERU
Applicants: MATSUTANI KAGAKU KOGYO KK, MATSUTANI CHEMICAL INDUSTRIES CO. LTD.
Application year: 1991
Main classification: A23L1
IPC codes: C12P19, A23L1, C08B30, A61K31, A61P3