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US-20260125726-A1 - METHOD FOR THE ENZYMATIC PRODUCTION OF SOLUBLE FIBRES

US20260125726A1US 20260125726 A1US20260125726 A1US 20260125726A1US-20260125726-A1

Abstract

The invention relates to a method for preparing a mixture of poorly-digestible alpha-glucans from a substrate rich in oligosaccharides having a degree of polymerization (DP) of 4.

Inventors

  • Pierre Lanos
  • Matthieu RAMETTE
  • Magali Remaud-Simeon
  • Claire Moulis
  • Sandra PIZZUT-SERIN
  • Etienne Severac

Assignees

  • ROQUETTE FRERES

Dates

Publication Date
20260507
Application Date
20230710
Priority Date
20220711

Claims (13)

  1. 1 . A method for preparing a mixture of alpha-glucans comprising a step of bringing together a substrate and an enzyme, said substrate being a syrup rich in oligosaccharides having a degree of polymerization (DP) of 4 and said enzyme being an alpha-glucanotransferase capable of cleaving alpha (1,4) glycosidic bonds and of creating alpha (1,6) glycosidic bonds.
  2. 2 . The method according to claim 1 , wherein the syrup rich in oligosaccharides having a DP of 4 comprises at least 40%, preferably at least 45%, even more preferably at least 50% of oligosaccharides having a DP of 4.
  3. 3 . The method according to claim 1 or 2 , wherein the syrup rich in oligosaccharides having a DP of 4 has a dextrose equivalent (DE) greater than 20.
  4. 4 . The method according to any one of the preceding claims , wherein the substrate is at a concentration of between 50 g/L and 500 g/L, preferably between 100 g/L and 200 g/L of reaction medium.
  5. 5 . The method according to any one of the preceding claims , wherein the alpha-glucanotransferase capable of cleaving the alpha (1,4) glycosidic bonds and of creating alpha (1,6) glycosidic bonds is the protein having the sequence SEQ ID No:1 or a protein having at least 90% identity with the protein having the sequence SEQ ID No:1.
  6. 6 . The method according to any one of the preceding claims , wherein the enzyme is at a concentration of between 0.01 and 1 mg/ml of reaction medium, preferably between 0.05 and 0.5 mg/mL, even more preferably approximately 0.1 mg/ml of reaction medium.
  7. 7 . The method according to any one of the preceding claims , characterized in that the substrate and the enzyme are brought together for a period of between 12 and 48 hours, preferably approximately 24 hours and/or at a temperature comprised between 2° and 40° C., preferably approximately 37° C. and/or at a pH of between 5 and 6.5, preferably approximately 5.75.
  8. 8 . The method according to any one of the preceding claims , characterized in that it further comprises a step of enzymatic treatment by an alpha-glucanotransferase capable of cleaving alpha (1,4) glycosidic bonds and of creating alpha (1,3) glycosidic bonds.
  9. 9 . The method according to the preceding claim , wherein the alpha-glucanotransferase capable of cleaving the alpha (1,4) glycosidic bonds and of creating alpha (1,3) glycosidic bonds is the protein having the sequence SEQ ID No:2 or a protein having at least 90% identity with the protein having the sequence SEQ ID No:2.
  10. 10 . A mixture of alpha-glucans capable of being obtained by the method according to any one of the preceding claims .
  11. 11 . The mixture of alpha-glucans characterized in that it has: a content of hydrolyzable fibers of less than 55%, preferably less than 50%, even more preferably less than 45%, and/or at least 20% alpha (1,6) bonds, wherein the fiber content corresponds to the hydrolyzable fraction according to the AOAC 2002.02 method and the percentage of alpha (1,6) bonds represents the molar percentage of alpha (1,6) bonds relative to the total number of glycosidic bonds, measured by the Hakomori method.
  12. 12 . Use of a mixture of alpha-glucans according to any one of claim 10 or 11 for preparing food for human or animal nutrition.
  13. 13 . Use of a glucanotransferase capable of cleaving the alpha (1,4) glycosidic bonds and of creating alpha (1,6) glycosidic bonds in order to reduce the digestibility of a mixture of alpha-glucans, said glucanotransferase having the sequence SEQ ID No:1 or a sequence having at least 90% identity with the protein having the sequence SEQ ID No:1.

Description

TECHNICAL FIELD The invention relates to a method for preparing a mixture of poorly-digestible alpha-glucans from a substrate rich in oligosaccharides having a degree of polymerization (DP) of 4. In the present application, this substrate designates a syrup containing oligosaccharides with a content of oligosaccharides having a degree of polymerization (DP) of 4 of at least 40%, preferably of at least 45%, even more preferably of at least 50%. The invention also relates to a mixture of poorly-digestible alpha-glucans. The present invention also relates to the use of an alpha-glucanotransferase capable of creating alpha (1,6) glycosidic bonds to reduce the digestibility of a mixture of alpha-glucans. PRIOR ART Dietary fiber has an important role in human nutrition. Among dietary fibers, a distinction is made between soluble fibers, which are soluble in water and have a gelling capacity, and insoluble fibers. Soluble fibers, including branched maltodextrins, are particularly advantageous because they are poorly digestible. Because of this, their incorporation into the diet makes it possible to reduce the glycemic index of a food and to prolong the sensation of satiety. They are also endowed with prebiotic properties on the intestinal flora; in other words, they are capable of selectively promoting the growth of certain bacteria of probiotic type or the activity of the microbiota, by providing a health benefit. Hitherto, soluble fibers, including branched maltodextrins, were mainly obtained physicochemically. This is the case in particular with maltodextrin sold by the Applicant company under the brand name NUTRIOSER FM10 as water-soluble fiber. Other soluble fibers obtained physicochemically exist, such as PROMITOR® sold by the company Tate and Lyl, FIBERSOL® or LITESSE® sold by the company Dupont Nutrition and Biosciences. Numerous studies have demonstrated that the digestibility properties were directly linked to the percentages of the various types of glycosidic bonds within the soluble fibers. Indeed, standard maltodextrins are rapidly digestible and are defined as purified and concentrated mixtures of glucose and glucose polymers essentially linked at alpha 1->4 (hereinafter 1->4 or alpha (1,4)) with only 4 to 5% of alpha 1->6 glycosidic bonds (hereinafter 1->6 or alpha (1,6)), of extremely varied molecular weights, completely soluble in water and of low reducing power. By increasing the percentage of alpha 1->6 or alpha 1->3 bonds, the degree of branching of the maltodextrins is increased, which makes them more resistant to digestion. The enzymatic approach, which uses enzymes capable of promoting the creation of “branched” type bonds, has numerous advantages, in terms of safety and environmental preservation, and also offers better specificity. Originally, most enzymatic processes for producing soluble fibers are carried out using sucrose as a substrate for the enzyme, in order to create new bonds. For example, WO2015183714 describes an enzymatic reaction from a mixture of sucrose and alpha-glucan type substrate. At present, most enzymatic processes use amylomaltases to produce soluble fibers from starch. It is desirable to obtain enzymatically soluble fibers from the substrate, in the absence of sucrose. DETAILED DESCRIPTION OF THE INVENTION The Applicant company has then found that it is possible, from a syrup rich in oligosaccharides having a degree of polymerization (DP) of 4, to obtain fibers of interest in human and animal nutrition, enzymatically. The Applicant company has thus developed a method that uses a particular enzyme, capable of creating alpha (1,6) bonds from syrup rich in DP4 oligosaccharides. In a first aspect, the present invention relates to a method for preparing a mixture of alpha-glucans, preferably a mixture of branched maltodextrins, comprising a step of bringing together a substrate and an enzyme, said substrate being a syrup rich in oligosaccharides having a degree of polymerization (DP) of 4 and said enzyme being an alpha-glucanotransferase capable of cleaving alpha (1,4) glycosidic bonds and of creating alpha (1,6) glycosidic bonds. According to the present invention, the terms “alpha-glucan”, “soluble fiber”, “food soluble fiber” are used interchangeably. They define oligosaccharides composed of at least 3 glucose units linked together by alpha-glycosidic (or alpha-glucosidic) bonds. The classification of alpha-glucans is mainly based on the measurement of their reducing power, conventionally expressed by the notion of “dextrose equivalent” (“Dextrose Equivalent” or DE). On this particular point, the definition of maltodextrins given in the Monograph Specifications of the Food Chemical Codex specifies that the DE value for a maltodextrin must not exceed 20. Above 20, these are glucose syrups. Such a DE measurement is however insufficient to accurately represent the molecular distribution of the alpha-glucans. Indeed, the acid hydrolysis of starch, which is totally random,