Acidified dairy products supplemented with fiber and methods of providing the same

Abstract

The present invention relates to the field of acidified dairy products, and more specifically, the present invention relates to the use of slowly or non-digestible dietary fiber and / or prebiotic fiber for increasing the viscosity of spoon-type acidified dairy products. The present invention provides a method for providing a spoon-type acidified dairy product, the method comprising the following steps: a) providing an α-glucan composition, the composition comprising substantially linear isomalt / maltopolysaccharide (IMMP), wherein the content of α(1#6) glycosidic bonds is at least 70%; b) supplementing the dairy product with the α-glucan composition; and c) acidifying the supplemented dairy product to a pH below 5, preferably to a pH of about 4.6. The present invention also provides a product obtainable by this method. The present invention also provides the use of IMMP having an α(1#6) glycosidic bond content of at least 70% for improving the stability and / or sensory properties of acidified dairy products.

Description

Technical Field

[0001] The present invention relates to the field of acidified dairy products. More specifically, the present invention relates to the use of slow or non-digestible, dietary, prebiotic polysaccharide fibers for increasing the viscosity of acidified dairy products. The present invention also provides a method for providing a spoonable acidified dairy product comprising such fibers and the products obtainable thereby. Background Art

[0002] The term "dietary fiber" was originally coined by Hipsley (British. Medical. J., 1953, vol. 2, p. 420-422) to describe the plant cell wall components of food. The existing Codex Alimentarius Guidelines define "dietary fiber" as "edible plant and animal materials that are not hydrolyzed by endogenous enzymes in the human digestive tract as determined by agreed methods." Typically, dietary fiber is classified as soluble or insoluble. Examples of soluble fibers include inulin, oligosaccharides, pectin, β-glucan, and polydextrose. On the other hand, cellulose, hemicellulose, lignin, wheat bran, and resistant starch are examples of insoluble fibers.

[0003] There is a large body of evidence that a high-fiber diet has significant health benefits, including a reduced risk of coronary heart disease, stroke, hypertension, diabetes, obesity, various cancers, and certain gastrointestinal diseases. There are multiple processes behind these benefits. For example, dietary fiber provides bulking and laxative effects that contribute to healthy bowel movements. In addition, dietary fiber slows the rate of absorption from the small intestine, especially the absorption of glucose.

[0004] One particularly relevant class of dietary fibers is prebiotic fibers. Prebiotic fibers are fermented by sugar-breaking (carbohydrate fermenting) microorganisms in the large intestine. These microorganisms are believed to be beneficial to human health. The fermentation of prebiotic fibers by these microorganisms produces short-chain fatty acids, which are absorbed by the intestine and have a variety of physiological effects. Examples of prebiotic fibers include fructooligosaccharides (FOS), galacto-oligosaccharides (GOS), lactulose, inulin, which can be found, for example, in chicory root, garlic, leeks, onions, asparagus, and wheat.

[0005] A diet rich in prebiotic fiber promotes the growth of these beneficial carbohydrate-fermenting microorganisms. This increases the ratio of beneficial carbohydrate fermenters to potentially harmful protein fermenters, resulting in a healthier gut microbiome.

[0006] The importance of dietary fiber, especially prebiotic fiber, to human health is now widely recognized. The World Health Organization recommends that adult males consume 30-40g per day and adult females consume 20-30g per day. However, this is difficult for most adults to achieve, especially in many Western societies. For example, most Americans only consume about half of the recommended daily amount of fiber.

[0007] A promising way to increase dietary fiber intake is to supplement popular processed foods with this fiber. Consumers can be encouraged to buy supplemented products that can be identified by labeling. For example, according to the European Commission's guidelines, processed foods can be labeled as "source of fiber" if the fiber concentration is at least 3% by weight. If the fiber concentration is at least 6% by weight, the "high fiber" label can be added to the product.

[0008] Prebiotic fibers used as supplements in processed foods can be isolated from plant sources. For example, inulin can be extracted from chicory root and beta-glucan can be extracted from oats. Prebiotic fibers can also be synthesized. For example, polydextrose can be synthesized from glucose.

[0009] Derivation of prebiotic fiber from starch could be an attractive alternative. Starch is a polysaccharide used by green plants as a means of storing energy and is usually found in high concentrations in such plants. This makes it a relatively cheap starting product. Rice, wheat, corn and potatoes are good sources of starch, with about 76% of potato dry matter consisting of starch.

[0010] Native untreated starch itself, i.e. starch granules, is not digested in the small intestine and is generally referred to as type 2 resistant starch. However, once dissolved (also referred to as gelatinized), when the starch is applied to food, it becomes easily digested by enzymes released in the mouth, stomach and small intestine due to its texture and thickening properties. Starch can be modified chemically or enzymatically to produce fibers with prebiotic properties. For example, WO2010 / 128859 discloses that a slowly or poorly digestible fiber composition can be obtained by treating starch with GTFB type α-glucanotransferase, and the resulting α-glucan can be used as a food additive to provide prebiotic fiber.

[0011] Spoonable acidified dairy products are an example of a popular processed food category that are often considered candidates for prebiotic fiber supplementation. Spoonable acidified dairy products have a smooth texture and are firm or viscous enough to be eaten with a spoon. Examples of spoonable acidified dairy products include yogurt, Greek yogurt, quark, skyr, curd, and fresh cheese. These products are appreciated for their delicate balance between freshness and creamy mouthfeel and smooth texture.

[0012] Acidified dairy products are also generally considered healthy. They are a good source of protein, vitamins, and calcium. In addition, if the acidified dairy product is cultured, it can contain live cultures of beneficial microorganisms that ferment carbohydrates. Consuming products containing these, called probiotics, helps improve the balance between good and bad bacteria in the intestines.

[0013] Although some non-digestible polysaccharides (exopolysaccharides) may be present, the fiber content of acidified dairy products is generally too low to classify these products as sources of fiber. Therefore, it is desirable to increase their potential health benefits by supplementing them with prebiotic fibers.

[0014] When supplementing acidified dairy products such as yogurt, it is important to maintain the desired creamy mouthfeel and smooth texture. The creaminess and smooth texture of acidified dairy products are key aspects of consumer preference for these products. Rheological properties and viscosity underlie these observable results, with thicker yogurts often being preferred by consumers. Summary of the invention

[0015] Supplementation of yoghurt with prebiotic fibres according to WO 2010 / 128859 has no positive effect on the viscosity of the yoghurt.The inventors therefore recognised the need for a method to increase the amount of prebiotic fibres in acidified dairy products without sacrificing the rheological properties of such products.

[0016] It has surprisingly been found that supplementing a dairy product with an α-glucan composition obtained by treating starch with both pullulanase and GTFB type α-(4,6)-glucanotransferase before acidification results in a yogurt having both a high content of slowly or non-digestible fibers and desirable rheological properties. The α-glucan composition comprises substantially linear isomalt / maltopolysaccharide (IMMP) characterized by a content of α(1→6) glycosidic bonds of at least 70%. Addition of this IMMP to a dairy product before fermentation results in a product having a significantly higher viscosity.

[0017] Therefore, in one embodiment, the present invention provides a method for providing a spoonable acidified dairy product, the method comprising the steps of:

[0018] a) providing an α-glucan composition comprising substantially linear isomalto / maltopolysaccharide (IMMP), wherein the content of α(1→6) glycosidic bonds is at least 70%;

[0019] b) supplementing dairy products with the α-glucan composition;

[0020] c) Acidifying the supplemented milk product to a pH below 5.

[0021] The present invention also provides a spoon-type acidified dairy product obtainable by the method according to the present invention. In another aspect, the present invention provides a spoon-type acidified dairy product comprising at least 1.5 wt%, preferably at least 3 wt%, more preferably at least 6 wt%, of substantially linear isomalt / maltopolysaccharides (IMMP) wherein the content of α(1→6) glycosidic bonds is at least 70%.

[0022] Although the need to supplement acidified dairy products with slow or non-digestible and / or prebiotic fibers is widely recognized, the methods of the present invention and products related thereto are not known or suggested in the art.

[0023] There are currently several yogurts on the market that are supplemented with the prebiotic inulin. However, inulin does not increase the viscosity of these yogurts and its application is preferably limited to low-viscosity products such as stirred yogurt and drinking yogurt.

[0024] According to Allgeyer et al. (2010), the addition of polydextrose does increase the viscosity of yogurt, but the resulting product is perceived as chalky.

[0025] WO2008 / 000913 states that a combination of soluble flax fibre and transglutaminase can be added prior to fermentation to increase the viscosity of acidified dairy products. However, prebiotic fibre alone is not sufficient to achieve the desired viscosity increase.

[0026] Alternatively, high molecular weight dextran can be used to increase the viscosity of acidified dairy products. For example, dextran with a molecular weight of 500 kDa (Mende et al., 2013[1]) or 2000 kDa (Pachekrepapol et al. (2015)[2]) has been shown to increase the viscosity of acidified milk gels. In addition, WO2005 / 048735 discloses that a fraction containing at least 20% β-glucan (extracted from oats and barley) with a molecular weight greater than 400 kDa can be added to yogurt to increase viscosity. It should be noted that such high molecular weight additives tend to cause phase separation in the dairy product due to depletion effects. In addition, the β-glucan-enriched fraction used in WO2005 / 048735 also contains protein and oil. It is unclear how these substances can contribute to the observed increase in viscosity, and their presence is undesirable from a sensory point of view.

[0027] Additionally, it is known in the art to supplement fermented dairy products with isomalto-oligosaccharides.

[0028] Samyang Foods and Taiwan BifidoFerment Co. already sell spoonable yogurts containing isomalto-oligosaccharides. See XP055745938 and XP055745940.

[0029] CN109769937 discloses a maltooligosaccharide yogurt and a preparation method thereof. The maltooligosaccharide yogurt is prepared from 6-15 parts by weight of starch, 0.01-1 parts by weight of alpha-amylase, 3-10 parts by weight of milk protein, 0.07-0.1 parts by weight of a starter and the remainder of milk, wherein the total weight parts are 1000. In this method, enzymolysis and fermentation are carried out simultaneously. By selecting suitable starch as a basic stabilizer and enzymolysis substrate and adding alpha-amylase, starch can be decomposed into maltooligosaccharides, dextrins, etc., and the probiotic health care properties of the yogurt can be further improved.

[0030] US2007 / 0082087 relates to a dairy product fermented by Bifidobacterium longum, Lactobacillus delbrueckii subsp. Bulgaricus and Streptococcus thermophilus, and isomalto-oligosaccharides are added as prebiotics to increase the number of Bifidobacterium longum in the fermented dairy product.

[0031] CN104041583 discloses an isomaltooligosaccharide yogurt, which comprises 2-15wt.% of isomaltooligosaccharide, fermented milk and 37wt.% of xylitol. Preferably, the isomaltooligosaccharide is IMO-90.

[0032] However, it is important to note that the IMMP used in the present invention is structurally different from IMO. IMO is a branched, non-fermentable oligosaccharide, also known as branched oligosaccharide or oligoglucose. Whereas IMO generally covers a DP range from 2 to about 6, IMMP is much larger (IMMP up to DP35 has been identified).

[0033] IMMP fibers for use in the present invention are known. Leemhuis et al. (2014) [3] describe the production of IMMPs by treating starch with pullulanase and GTFB type α-(4,6)-glucanotransferase. However, Leemhuis et al. do not mention the possible use of such IMMPs in acidified dairy products. Furthermore, Leemhuis et al. do not provide any information or suggestions on how these IMMPs may affect the viscosity of such products.

[0034] Thus, there is no teaching or suggestion in the art to use IMMP fibers having at least 70% α(1→6)-glycosidic bonds to increase the viscosity of the acidified milk products disclosed herein.

[0035] IMMPs for use in the present invention include substantially linear α-glucans having one or more glucose units linked by α(1→4) at the reducing end and one or more glucose units linked by α(1→6) glycosidic bonds at the non-reducing end. In order to be useful for microbial fermentation in the large intestine, such IMMP fibers must be resistant to digestion by human enzymes. Human enzymes can only degrade a small fraction of the glycosidic bonds present in polysaccharides. Particularly relevant to IMMP digestion are pancreatic amylase and salivary amylase. Amylases hydrolyze α(1→4) glycosidic bonds in polysaccharides and break down their natural substrates (such as starch and glycogen) into maltose and glucose. The major form of amylase in mammals is α-amylase. This enzyme can only act on α(1→4) bonds in starch with at least three consecutive α(1→4) glycosidic bonds.

[0036] Humans rely primarily on amylase to digest carbohydrates. This enzyme is not able to hydrolyze α(1→6) glycosidic bonds. Therefore, polysaccharides with increased α(1→6) glycosidic bond content are less susceptible to digestion in the small intestine and can be considered as slowly or poorly digestible soluble fibers. As used herein, the α(1→6) bond content is defined as (the number of α(1→6) bonds) / ((the number of α(1→6) bonds)+(the number of α(1→4) bonds)).

[0037] The IMMPs used in the present invention have a content of α(1→6) bonds of at least 70%. Preferably, the IMMPs have a content of α(1→6) glycosidic bonds of at least 72%, more preferably at least 74%. In another preferred embodiment, they contain 75% to 99% α(1→6) glycosidic bonds, such as 76%, 78%, 79%, 82%, 85%, 87%, 90%, 91%, 93%, 94%, 96%, 97% or 98%.

[0038] With regard to the viscosity increase of the supplemented acidified dairy product, good results were obtained using IMMP wherein the content of α(1→6) glycosidic bonds was about 70%, 77% or 87%. Thus, in particularly preferred embodiments, the extent of α(1→6) glycosidic bonds is in the range of 70-90%, such as 70-75%, 74-77%, 75-85%, 80-90%.

[0039] IMMPs containing about 96% α(1→6) glycosidic bonds also show a desirable effect on the viscosity of acidified dairy products. Thus, in another embodiment, the content of α(1→6) glycosidic bonds is in the range of 90-98%, preferably about 95-97%.

[0040] In a particularly preferred embodiment, the IMMP used according to the invention has a content of α(1→6) glycosidic bonds of between 80% and 100%, preferably between 82% and 99%, most preferably between 85% and 98%, for example 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96% or 97%.

[0041] The chain length of the IMMP may vary. In one embodiment, the molecular weight of the IMMP is between 1.0*10 3 and 1.0*10 6 Preferably, the oligosaccharide (part) has a DP of at least 20, more preferably at least 30 glucose residues. In a particularly preferred embodiment, the DP of the oligosaccharide (part) is between 25 and 6200, preferably between 30 and 700, more preferably between 35 and 400.

[0042] The IMMP used in the present invention is substantially linear. In other words, the IMMP has a low degree of branching, where the degree of branching is defined as ((the number of α(1→4,6) branch points) / (the number of glucose residues))*100%. In one embodiment, the degree of branching is less than 5%. Preferably, the degree of branching of the IMMP is less than 4%, more preferably less than 3%, and even more preferably less than 2%. In a particularly preferred embodiment, the IMMP has a degree of branching of less than 1%.

[0043] In a specific embodiment, the isomalt / maltopolysaccharide (IMMP) used in the present invention comprises a linear (i.e., non-branched) glucooligosaccharide of the general formula AB, a glucan comprising such a linear part, or a mixture comprising different glucooligosaccharides / parts of the general formula AB, characterized in that (i) the bond between part A and part B is an α(1→6) glycosidic bond; (ii) part A comprises at least two consecutive α(1→6) glycosidic bonds; (iii) part B comprises at least two consecutive α(1→4) linked glucose residues; and (iv) wherein the content of α(1→6) glycosidic bonds is at least 70%. Linear glucooligosaccharides of the general formula AB are particularly preferred.

[0044] Therefore, the present invention also relates to a method for providing a spoonable acidified dairy product, the method comprising the following steps:

[0045] a) An α-glucan composition comprising an IMMP is provided, wherein the IMMP comprises a linear (i.e., non-branched) oligoglucosaccharide of the general formula AB, a glucan comprising such a linear portion, or a mixture of different oligoglucosaccharides / portions of the general formula AB, characterized in that (i) the bond between portion A and portion B is an α(1→6) glycosidic bond; (ii) portion A comprises at least two consecutive α(1→6) glycosidic bonds; (iii) portion B comprises at least two consecutive α(1→4) linked glucose residues; and (iv) the content of α(1→6) glycosidic bonds is at least 70%.

[0046] b) supplementing a dairy product with the α-glucan composition; and

[0047] c) acidifying the supplemented milk product to a pH below 5, preferably to a pH of about 4.6.

[0048] Preferably, part A comprises isomaltooligosaccharides with a DP of at least four glucose residues. For example, part A is an isomaltooligosaccharide consisting of four glucose residues. Part A with higher DP is preferred because they are thought to make IMMP less susceptible to human enzyme digestion. Therefore, in a preferred embodiment, part A has a DP of at least 15, preferably at least 25, more preferably at least 35, and most preferably at least 50 glucose residues.

[0049] Part B consists of a series of consecutive α(1→4) linked glucose residues. For example, part B consists of two, three, four or five consecutive α(1→4) linked glucose moieties.

[0050] The IMMP used in the present invention can be obtained by subjecting a starch substrate to treatment with a debranching enzyme and to treatment with a GTFB type 4,6-α-glucanotransferase.

[0051] GTFB type 4,6-α-glucanotransferases suitable for the present invention include those disclosed in WO2010 / 128859. GTFB type 4,6-α-glucanotransferases cleave the non-reducing glucose portion of (1→4)-α-D-glucooligosaccharides and attach the glucose portion to the non-reducing end of another α(1→4)-glucan chain via an α(1→6) bond without forming a branch. Repeat this cycle to build a linear α-glucan with continuous α(1→6) bonds on the (1→4)-α-D-glucooligosaccharides.

[0052] When reaching the branch point in the glucose donor substrate, the GTFB type 4,6-α-glucanotransferase will stop. Therefore, there is a negative correlation between the degree of branching in the starch substrate and the degree of α(1→6) glycosidic bonds in the IMMP product. In order to obtain the high degree of α(1→6) glycosidic bonds desired in the present invention, the starch substrate needs to be debranched.

[0053] Therefore, in one embodiment, an IMMP having an α(1→6) bond content of at least 70% is provided by (i) providing a starch substrate; (ii) treating the starch substrate with a debranching enzyme; and (iii) treating the (partially) debranched starch substrate with a GTFB type 4,6-α-glucanotransferase. During the enzymatic conversion, the percentage of α(1→6) bonds gradually increases at the expense of α(1→4) bonds. Products having more than 90% α(1→6) bonds can be obtained, while products having a low percentage of α(1→6) bonds can be obtained by shortening the reaction time.

[0054] Therefore, the present invention also provides a method for providing a spoonable acidified dairy product, the method comprising the steps of: a) treating a starch substrate with a debranching enzyme; and treating the (partially) debranched starch substrate with a GTFB type 4,6-α-glucanotransferase to provide an α-glucan composition comprising IMMP, the IMMP being characterized by a content of α(1→6) glycosidic bonds of at least 70%; b) supplementing a dairy product with said α-glucan composition; and c) acidifying the supplemented dairy product to a pH below 5, preferably to a pH of about 4.6.

[0055] In one embodiment, the enzyme treatment steps are performed sequentially. That is, the treatment of the starch substrate with a debranching enzyme can precede the treatment with a GTFB-type 4,6-α-glucanotransferase. However, from an industrial perspective, it is generally desirable to perform these enzyme treatments simultaneously. In addition, a high degree of α(1→6) bonds has been observed if the starch substrate is treated with a debranching enzyme pullulanase and a GTFB-type 4,6-α-glucanotransferase simultaneously. Therefore, in a preferred embodiment, IMMP is obtained by treating a starch substrate with a debranching enzyme and a GTFB-type 4,6-α-glucanotransferase simultaneously.

[0056] Suitable debranching enzymes include pullulanase (EC 3.2.1.41), isoamylase (EC 3.2.1.68) or limit dextrinase (3.2.1.142). In a preferred embodiment, the debranching enzyme is a pullulanase or an isoamylase, preferably a pullulanase.

[0057] The first known GTFB type 4,6-α-glucanotransferase has been identified in Lactobacillus reuteri 121. However, GTFB homologs exist in several Lactobacillus strains. Therefore, in one embodiment, the GTFB type 4,6-α-glucanotransferase used in the present invention is selected from GTFB from Lactobacillus reuteri 121, GTFB106B from Lactobacillus reuteri TMW 1.106, GTML4 from Lactobacillus reuteri ML1, GTML5 from Lactobacillus reuteri DSM 20016, GTML6 from Lactobacillus reuteri ML2, GTML7 from Lactobacillus reuteri ML3, GTML8 from Lactobacillus reuteri ML4, GTML9 from Lactobacillus reuteri ML5, GTML106 from Lactobacillus reuteri ML6, GTML11 from Lactobacillus reuteri ML121, GTFB106B from Lactobacillus reuteri TMW 1.106, GTML12 from Lactobacillus reuteri ML121, GTFB106B from Lactobacillus reuteri TMW 1.106, GTML4 from Lactobacillus reuteri ML121, GTFB106B ... A GTFDSM and GTF from Lactobacillus fermentum ATCC14931 or its homologs, which show at least 55%, preferably at least 65%, more preferably at least 75%, most preferably at least 85% sequence identity. In a preferred embodiment, the GTFB type 4,6-α-glucanotransferase used in the present invention is GTFB from Lactobacillus reuteri 121.

[0058] Although neither debranching enzymes nor GTFB-type 4,6-α-glucanotransferases introduce an α(1→4,6) branch point, the IMMPs obtainable by these enzymes may still have some residual branching from the substrate. However, the degree of branching in IMMPs is always lower than that in starch substrates.

[0059] Any native or unmodified starch can be used as a starting material for obtaining the IMMP for use in the present invention. For example, the IMMP can be derived from cereal starches, such as corn starch, wheat starch, rice starch, barley starch and rye starch. Alternatively, root or tuber starches, such as tapioca starch, potato starch and sweet potato starch, or leguminous starches, such as pea, lentil and kidney bean starch can be used as starting materials. The ratio of amylose to amylopectin of these starches is in the range of 1:3 to 1:7. However, waxy starches with a higher amylopectin content are also suitable substrates according to the method of the present invention. Examples include waxy tapioca, waxy corn, waxy potato, waxy rice and waxy barley starch. In addition, other starch sources that can be used, such as mung bean, wrinkled pea and high amylose corn starch, are rich in amylose.

[0060] This list is not exhaustive, but it should be understood that starch from any source, high amylopectin (waxy) starch and high amylose starch can be used as starting material to obtain IMMP for use in the present invention. The starch used as starting material can be from non-transgenic as well as transgenic plant variants.

[0061] In addition to native starch, modified starch or derived starch can also be used. Many derivatization methods are known to those skilled in the art (OB Wurzburg, Modified starches-properties and uses, CRC Press Inc, Boca Raton US, 1986 ISBN: 0-8493-5964-3). These derivatizations include cross-linking, enzymatic degradation, acid degradation, oxidation, etherification, esterification, dry roasting, dextrinization, etc. In addition, some physical treatments may change the function of starch. For example, drum drying, spray cooking and extrusion can make starch soluble in cold water. In a preferred embodiment, food grade potato starch is used as starting material to obtain IMMP for the present invention.

[0062] In order to obtain a spoonable acidified dairy product according to the invention, the dairy product is supplemented with IMMP. Supplementation with IMMP increases the viscosity of the final acidified dairy product to a desired extent compared to other prebiotic fibers. Supplementation with 1.5 wt% IMMP-87 increases the Brookfield viscosity of a set yogurt by nearly 10%. Thus, in one embodiment, the supplemented dairy product comprises at least about 1 wt% IMMP. Preferably, the supplemented dairy product comprises at least 1.5 wt%, more preferably at least 2 wt%, most preferably at least 2.5 wt% IMMP.

[0063] The Brookfield viscosity of the resulting yogurt or acid milk gel increases approximately linearly with the IMMP content within the tested range. Although higher IMMP contents are certainly possible, in practice, the upper limit is set to about 20 wt % in order to keep the final acidified dairy product within the desired viscosity range. For stirred yogurts, the viscosity range is typically between 5000 mPas and 70000 mPas, measured at 10 rpm with a Brookfield DV2 equipped with a helipath spindle at a temperature between 4° C. and 6° C. Therefore, in one embodiment, the dairy product is supplemented with 1 wt % to 20 wt %, preferably 1.5 wt % to 15 wt %, more preferably 2 wt % to 12 wt % IMMP.

[0064] The desired viscosity increase can be obtained when the milk product is supplemented with 3 wt% to 12 wt% IMMP. Therefore, in a particularly preferred embodiment, the milk product is supplemented with 3 wt% to 12 wt%, such as 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt% or 12 wt% IMMP.

[0065] According to the method of the invention, a variety of dairy products can be used as starting materials to obtain a spoon-type acidified dairy product supplemented with IMMP. For example, the dairy product can be original or processed. Whole (full fat), skimmed (fat-free) or semi-skimmed milk are suitable as starting materials. These can be fresh or reconstituted, for example from dry milk powder. Concentrated milk can also be used as starting material. The dairy product can also be a mixture of the above-mentioned dairy products. For example, the dairy product comprises whole and semi-skimmed milk, or it comprises fresh and reconstituted and / or concentrated milk.

[0066] Traditionally, acidified dairy products are made from milk produced by mammals. The most common example is cow's milk. Other examples include goat's milk, sheep's milk, buffalo's milk, and camel's milk.

[0067] Recently, plant-based milk substitutes have become increasingly popular. Plant-based milk substitutes, commonly referred to as plant beverages or plant drinks, can be made from grains (e.g., barley, corn, millet, oats, rice, spelt and wheat), pseudocereals (e.g., buckwheat and quinoa), legumes (e.g., peas, peanuts and soy), nuts (e.g., almonds, Brazilwood, cashews, hazelnuts, macadamia nuts, pecans and walnuts), seeds (e.g., chia seeds, flax seeds, hemp seeds and pumpkin seeds), fruits (e.g., coconuts) and tubers (e.g., potatoes and cyperus). Common plant-based milk substitutes on the market today include almond drinks, coconut drinks, oat drinks and soy drinks. Plant-based milk substitutes have several advantages over animal milk. In addition to being suitable for strict vegetarians, plant-based milk substitutes do not contain lactose and are safe for lactose intolerant people to consume. In addition, their environmental footprint is generally lower than that of animal milk.

[0068] Although the list is not complete, it should be clear that the milk product to be supplemented can be of animal or plant origin. Mixtures of milk from different sources can also be used in the present invention. Optionally, the milk product can be supplemented with sugars, such as sucrose of glucose. In a preferred embodiment, the milk product is animal milk. Particularly preferably, cow's milk is used.

[0069] In particular, in the production of acidified dairy products on a commercial scale, the (fresh) dairy product is pasteurized, homogenized and cooled before inducing acidification. Thus, in one embodiment, the dairy product for use in the present invention is homogenized, pasteurized and cooled before supplementation with IMMP. In a preferred embodiment, the dairy product is homogenized, pasteurized and cooled after supplementation with IMMP but before acidification.

[0070] Acidification is essential to achieve the fresh taste and unique texture of acidified dairy products. Lowering the pH to below 5, typically to around 4.6, causes the proteins in dairy products to unfold and aggregate. For example, in animal milk, casein micelles aggregate upon acidification to form a fatty casein network.

[0071] Thus, the method of the present invention comprises the step of acidifying the supplemented milk product to a pH below 5. This step comprises adding an acidulant to the milk product. The acidulant may be a chemical acidulant or a microbial acidulant.

[0072] A chemical acidulant is a compound that is capable of gradually or instantaneously lowering the pH of a supplemented milk product. Chemical acidulants suitable for use in the present invention include food-acceptable acids and / or lactones. Carboxylic acids such as citric acid, tartaric acid, acetic acid and lactic acid are examples of suitable food-acceptable acids. An example of a useful lactone is glucan delta-lactone (GDL).

[0073] Thus, in one embodiment, acidification of the supplemented dairy product comprises adding a chemical acidulant. Preferably, the chemical acidulant comprises a food acceptable acid and / or lactone. For example, the chemical acidulant comprises one or more compounds selected from the group consisting of acetic acid, citric acid, lactic acid, malic acid, succinic acid, tartaric acid and glucono delta-lactone. Preferred acids for acidifying the supplemented dairy product are lactic acid and citric acid.

[0074] In certain aspects, glucono delta-lactone is used to acidify supplemented dairy products. Glucono delta-lactone (GDL), also known as gluconolactone, is a food additive with an E number of E575, commonly used as a chelating agent, acidulant or firming agent, acidulant, or leavening agent. It is a lactone of d-gluconic acid. Pure GDL is a white, odorless, crystalline powder. GDL has been commercially used in feta cheese. GDL is neutral, but hydrolyzes to acidic gluconic acid in water.

[0075] The actual concentration of the chemical acidulant depends on the identity of the agent and the specific formulation of the supplemented milk product.Sufficient amounts of the chemical acidulant are added to lower the pH of the supplemented milk product to below pH 5, preferably to about pH 4.6.

[0076] Alternatively, a microbial acidifier may be used to acidify the supplemented milk product. A microbial acidifier is a bacterial culture, often referred to as a starter culture or inoculant. In this case, the acidification step is essentially an inoculation of the supplemented milk product to obtain an inoculated supplemented milk product.

[0077] Starter cultures used to produce acidified dairy products, such as yogurt, typically include one or more strains of lactic acid bacteria. These lactic acid bacteria ferment the sugars present in milk, producing lactic acid. There are two different phyla of lactic acid bacteria: Firmicutes and Actinobacteria. Genera such as Lactobacillus, Lactococcus, Leuconostoc, Streptococcus, and Enterococcus belong to the Firmicutes, while Bifidobacterium species belong to the Actinobacteria. Lactic acid bacteria used to produce acidified dairy products include Lactobacillus, Leuconostoc, Lactococcus, Streptococcus, and Pediococcus sp. For example, yogurt is usually obtained by inoculating milk products with Lactobacillus delbrueckii ssp., Lactobacillus bulgaricus and Streptococcus thermophiles.

[0078] In principle, any type of starter culture traditionally used for making yogurt and other cultured acidified dairy products can be used in the present invention. Starter cultures used in the dairy industry are usually mixtures of lactic acid bacteria strains. However, single-strain starter cultures can also be used. In the method of the present invention, a starter culture (including commercial starter cultures) can be used as an acidifier, which starter culture contains one or more lactic acid bacteria species selected from the group consisting of Lactobacillus, Leuconostoc, Lactococcus, Streptococcus and Pediococcus.

[0079] Thus, in one embodiment, the acidification of the milk product supplemented with IMMP in the method of the present invention comprises inoculating the milk product with at least one lactic acid producing microbial strain and allowing fermentation. Preferably, the lactic acid producing microorganism is selected from the group consisting of Lactobacillus, Leuconostoc, Lactococcus, Streptococcus and Pediococcus. More preferably, it is selected from the group consisting of Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus bifidus, Lactobacillus bulgaricus and Streptococcus thermophilus.

[0080] Regarding the preparation of quark, different microorganisms can be used to inoculate the IMMP-supplemented dairy product. Typically, lactic acid-forming microorganisms of the species Streptococcus lactis and Streptococcus cremoris are used. In addition, Leuconostoc mesenteroides spp cremoris and / or Streptococcus diacetylactis are used to induce flavor. Some yogurt or yogurt culture can also be added during inoculation.

[0081] Thus, in another embodiment, the acid-producing microorganism is selected from the group consisting of Streptococcus lactis and Streptococcus cremoris, optionally in combination with Leuconostoc mesentericus and / or Streptococcus diaceticus.

[0082] An inoculum or starter culture comprising a plurality of lactic acid producing microorganisms is generally used to induce acidification of a dairy product. Thus, in another embodiment, a dairy product supplemented with IMMP is inoculated with a starter culture comprising at least two different lactic acid bacteria strains. For example, the inoculum comprises Lactobacillus delbrueckii subsp., Lactobacillus bulgaricus and Streptococcus thermophilus.

[0083] When inoculated, the supplemented milk product is maintained under conditions that favor optimal growth conditions for the different microorganisms. This means that the product is allowed to ferment without substantial agitation. Typical fermentation temperatures range from about 30 to about 45°C for 2 to 20 hours. Initial fermentation can usually be terminated by cooling when the mixture reaches a pH of about 4.6. For quark, some rennet is added after the milk product has been inoculated with the microorganisms and before incubation. Typically, fermentation of quark is carried out at 20°C for about 24 hours.

[0084] The probiotic properties of the acidified dairy product of the present invention can be enhanced by adding one or more probiotic organisms, such as Lactobacillus casei, Lactobacillus gasseri, Lactobacillus plantarum, Lactobacillus johnsonii, Lactobacillus reuteri, Lactobacillus rhamnosus, Bifidobacterium bifidum, Bifidobacterium lactis, Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium infantis, Enterococcus faecium, Enterococcus faecalis, Streptococcus salivarius. salivarius or the yeast Saccharomyces boulardii. Probiotic microorganisms can be added before, during or after fermentation or chemical acidification.

[0085] The resulting acidified dairy product can be further processed. For example, it can be stirred or filtered to remove whey. Due to differences in the acidification process (including inoculum and fermentation scheme, as well as post-treatment), a variety of acidified dairy products can be obtained. Examples include yogurt, Greek yogurt, quark, skim yogurt, curd or cheese.

[0086] Preferably, the spoonable acidified dairy product of the present invention is yogurt, Greek yogurt, stirred yogurt, quark, skim yogurt, curd or cottage cheese. A spoonable acidified dairy product with high viscosity, such as Greek yogurt or skim yogurt is particularly preferred. More preferably, the dairy product of the present invention is yogurt, such as set yogurt or stirred yogurt. Most preferably, the dairy product of the present invention is stirred yogurt.

[0087] Such products may also be supplemented with conventional food additives, such as natural or artificial sweeteners, antioxidants, coloring agents, flavorings, preservatives or other functional ingredients. Additives used in acidified dairy products are well known in the art, for example, as described in Kirk-Othmer Encyclopedia of Chemical Technology, 4th edition, volume 11, "Food Additives", pages 805-833.

[0088] Acidified dairy products are usually stored at temperatures around 2-7°C for a period of days to weeks. Storage may have a negative impact on texture and sensory properties. For example, syneresis, as whey separates from the milk protein gel, is thought to reduce the sensory appeal of acidified dairy products. Increasing viscosity is thought to stabilize the texture of acidified dairy products, thereby avoiding or slowing down processes such as syneresis.

[0089] Thus, in one embodiment, the present invention provides the use of substantially linear isomalto / maltopolysaccharides (IMMPs) wherein the content of α(1→6) glycosidic bonds is at least 70%, preferably wherein the IMMP comprises a linear (i.e. unbranched) glucooligosaccharide of the general formula AB, a glucan comprising such a linear portion, or a mixture comprising different glucooligosaccharides / portions of the general formula AB, characterized in that (i) the bond between portion A and portion B is an α(1→6) glycosidic bond; (ii) portion A comprises two or more consecutive α(1→6) glycosidic bonds, preferably wherein portion A comprises an isomalto-oligosaccharide having a degree of polymerization of at least 4 glucose residues; (iii) portion B comprises at least two consecutive α(1→4) linked glucose residues, to increase the viscosity of an acidified dairy product.

[0090] The present invention also provides the use of such IMMP for improving the stability and / or organoleptic properties of acidified dairy products. DETAILED DESCRIPTION

[0091] Examples

[0092] Example 1: Preparation of IMMP fibers

[0093] IMMP fibers suitable for use in the present invention are prepared by enzymatic treatment of starch with pullulanase (EC 3.2.1.41) and GTFB type 4,6-α-glucanotransferase. In this example, IMMP obtained by GTFB type 4,6-α-glucanotransferase alone was compared with IMMP obtained by both pullulanase and GTFB 4,6-α-glucanotransferase. In addition, IMMP obtained by sequential or simultaneous treatment with pullulanase and GTFB type 4,6-α-glucanotransferase were compared.

[0094] Therefore, three different synthetic routes were compared. Each route started with gelatinization of starch followed by one of three treatments: (i) GTFB-type 4,6-α-glucanotransferase (GTFB) enzymatic treatment alone, (ii) debranching first followed by GTFB enzymatic treatment, or (iii) simultaneous debranching and GTFB treatment.

[0095] The commercially available pullulanase Promozyme D6 (Novozymes, batch ATN60003) was used as the debranching enzyme. The GTFB enzyme used was a truncated version of the 4,6-α-glucanotransferase GTFB from Lactobacillus reuteri 121, denoted GTFBdNdC. This was produced by Avebe as described in Bai et al. 2015 and 2017 [4][5].

[0096] Before enzyme treatment, potato starch (Avebe, batch G3771649) was gelatinized by jet cooking with tap water at a mass ratio between 1:4 and 1:7 and a temperature of 160°C in a jet cooker at Henan Laboratory. The gelatinized starch (5 or 10 L) was poured into a preheated RVS steel reaction vessel. CaCl2 (Merck, batch A609182) was added to a final concentration of 1 mM, the temperature was set at the indicated temperature, and 3 M acetic acid (VWR, batch 16D254124) was added to set the pH. At this point, the enzyme treatment was performed by one of the following methods:

[0097] i) setting the temperature to 40°C, adjusting the pH to 4.7, adding GTFB enzyme to a final concentration of 30k units per kg of starch, and incubating for 43 hours. After 43 hours, the reaction was stopped by heating to above 90°C for 30 minutes. The reaction mixture was cooled to 50 to 60°C;

[0098] ii) Set the temperature to 58.5°C, adjust the pH to 4.7, add 0.2 wt% of liquid Promozyme D6 per kg of starch, and then incubate overnight. Terminate the reaction by heating to 80°C (internal temperature) for 30 minutes. After cooling to 40°C, if necessary, readjust the pH to 4.7 and add 30k units of GTFB enzyme per kg of starch. After incubation for 26 hours, stop the reaction by heating to 90°C. Cool the reaction mixture to 50-55°C;

[0099] iii) The temperature was set to 40°C, the pH was adjusted to 4.7, 23.7 k units of GTFB enzyme were added per kg of starch, and 0.05 wt% of liquid Promozyme D6 was added per kg of starch after 15 minutes. After overnight incubation, 0.05 wt% of liquid Promozyme D6 was added per kg of starch. After a total incubation time of 36 hours (for products with a lower percentage of α(1→6) bonds, the incubation time was shortened), and the reaction was terminated by heating to above 90°C for at least 15 minutes. After the reaction mixture was cooled to between 50-60°C, it was optionally filtered using a Buchner with Whatmann paper.

[0100] Subsequently, proteins and salts were removed by ion exchange involving the addition of (i and ii) about 10% v / v Amberlite MB 20 resin (Dow, rinsed thoroughly with demineralized water before use) or (iii) about 10 v / v Amberlite FPA40 Cl resin (Dow, batch A075EAG043) and Amberlite 252 resin (Dow, batch A075 DBH033) and incubation for 45-60 minutes. The resins were prepared according to the manufacturer's instructions. The mixture was filtered through a 45 μm sieve and, in the case of iii, also using a Buchner with Whatmann paper. 4% NaOH solution (Merck, batch 1.06482.500) was added and the pH was adjusted to about 6. A 4% NaOH solution (Merck, batch 1.06482.500) was used with a nozzle (T 入 250℃, T 出 110℃) or with wheel sprayer (T 入 270℃, T 出 The product was spray dried in an Anhydro Denmark spray dryer at 140°C.

[0101] The glucose equivalent (DE) of the product was quantified using the Luff-Schoorl procedure. The content of α(1→6) bonds was quantified by NMR spectroscopy. The 1HNMR spectrum was tested in D2O at 340K using a 600MHz Bruker machine. The fraction of α(1→6) glycosidic bonds was calculated by dividing the α(1→6) of the anomer by the sum of the α(1→4) and α(1→6) signals of the anomer. The molecular weight distribution of the product was analyzed by GPC-RI-MALLS. In brief, the carbohydrate product was dissolved in 50mM NaNO3. The sample was filtered (0.5μm) before injection. The system consisted of a HPLC-Dionex Ultimate 3000 equipped with a GPC column (Shodex-OHpak SB-803HQ, 8.0 x 300 mm), a refractive index detector (Wyatt-Optilab T-rEx 658 nm) and a multi-angle laser scattering detector (Wyatt-Dawn Heleos II (angle 18)). The molecular characteristics of the products are summarized in Table 1. NMR analysis showed that the product obtained from route i had only 25% α (1 → 6) -glycosidic bonds, while the products of route ii and route iii had 76% and 87% α (1 → 6) -glycosidic bonds, respectively. In addition, the product obtained by route i had a much higher molecular weight than the products obtained by route ii or iii.

[0102] Table 1. Effect of preparation method on the molecular properties of IMMP products

[0103]

[0104] 1 About 75% of the product had a molecular weight of 6000 kDa and about 25% of the product had a molecular weight of about 300 kDa.

[0105] 2 The majority of the product had a molecular weight of 15 kDa, but a small portion had a significantly higher molecular weight.

[0106] As shown in Table 1, the IMMP obtained by treatment with only GTFB-type enzyme has a significantly lower content of α(1→6) bonds than the IMMP obtained using pullulanase and GTFB-type enzyme. This indicates that debranching is essential for obtaining a high content (>70%) of α(1→6) bonds.

[0107] The IMMPs obtained by sequential and simultaneous treatment with the two enzymes have very similar properties.Thus, IMMPs suitable for the method of the present invention can be obtained by treating starch with a debranching enzyme and a GTFB type 4,6-α-glucanotransferase simultaneously or sequentially.

[0108] Example 2: Effect of the α(1-6) glycosidic bond content of IMMP on yogurt viscosity

[0109] In this example, the effect of the α(1→6) bond content of IMMP fibers on the viscosity of yogurt was evaluated.

[0110] Yogurts containing 3 wt% of different IMMPs prepared in Example 1 and following the recipe of Table 2 were prepared as follows.

[0111] First, prepare a 10% starter culture stock solution by heating 90 g of milk to 40-50° C. in a sterile beaker and dissolving 10 g of Delvo culture (DSM, batch FVV-221). For 800 g of yogurt mix, 1.6 ml of starter culture must be added before fermentation.

[0112] Weigh the milk and water and add to a Thermomix beaker, set it to 40°C and stir. Add skimmed milk powder (SMP) and IMMP (carbohydrates) and hydrate at 40°C for 10 minutes. Subsequently, preheat the mixture to 65°C for 30 seconds and homogenize at 150 / 50 bar. It is then pasteurized at 85°C for 5 minutes and cooled to 40°C. Add the starter culture stock solution (1.6ml / 800g of milk mixture) and incubate the mixture in a beaker in a 32°C water bath to allow fermentation. After fermentation, cool the yogurt to 8-10°C, homogenize with IKA magic at 3000rpm, fill in sterile plastic containers and place in a refrigerator at 4-6°C.

[0113] Table 2. Yogurt recipe

[0114]

[0115] The viscosity of the yogurt was measured using Anton Paar modular compact rheometers MCR302 SN81328338 and SN81464746, cup rotors CC27 SN23477 and SN32606. The temperature was set at 10 °C. After placing the sample in the rheometer, it was left for a 300 s waiting period to allow for the reorganization of the network. Subsequently, a 10 s -1 The viscosity at the beginning and end of the 2-minute measurement is reported in Table 3.

[0116] Table 3. Changes of yogurt viscosity over time

[0117]

[0118] As can be seen from Table 3, despite the high molecular weight of IMMP-25 (characterized by a 25% α(1→6) bond content), the addition of it had a negligible effect on the viscosity of the yogurt. In contrast, the addition of IMMP-87 (containing 87% α(1→6) bonds) produced a significant increase in the viscosity of the yogurt.

[0119] Thus, this example shows that a high content of α(1→6) linkages is essential to obtain the desired viscosity increase. See also Example 7 below, which demonstrates the promising effect of adding IMMP with 70% or more α(1→6) linkages on yogurt.

[0120] Example 3: Comparison between IMMP and other slowly digesting and / or prebiotic fibers

[0121] In this example, IMMP fibers containing 87% or 96% α(1→6) bonds were mixed with exemplary prebiotics or slow digesting fibers to determine the effect on yogurt viscosity. Compare with VitaFiberTM. is an inulin-type soluble prebiotic fiber with nutritional and functional properties. It is a powdered food ingredient based on chicory inulin with very high purity used to improve texture and mouthfeel in various food applications. Inulin from chicory is a polydisperse mixture of linear fructose polymers that have mainly terminal glucose units coupled via β(2-1) bonds. The number of units (degree of polymerization) can vary from 2 to 60. Composed of over 99.5% fructooligosaccharides / inulin. VitaFiber TM An isomalto-oligosaccharide made from a non-GMO, grain-free starch source. VitaFiber TMIt is a mixture of branched oligosaccharides containing 50 / 50 α(1→4) and α(1→6) bonds. It has good solubility and is used as a low-calorie sweetener. It is considered to be difficult to digest in the small intestine.

[0122] Table 4. Yogurt recipe

[0123]

[0124] Yogurts were prepared according to the recipes in Table 4. All recipes contained about 3 wt% fat and 4 wt% protein. Yogurts were prepared according to the steps outlined in Example 2. Note that the measured moisture content of carbohydrates was used to adjust the amount of carbohydrates so that each yogurt (except the negative control) contained 3% carbohydrate dry matter content. All recipes were prepared in duplicate, except for the yogurt containing IMMP-96 (containing 96% α(1→6) bond content, prepared according to method (iii) of Example 1).

[0125] On day 7 after fermentation, the viscosity of the yogurt was measured using Anton Paar modular compact rheometers MCR302 SN81328338 and SN81464746, cup rotors CC27 SN23477 and SN32606. The temperature was set to 10 °C. After placing the sample in the rheometer, the measurement was started with a waiting period of 300 seconds to allow for network reorganization. The shear rate was set to increase linearly from 0.01 to 100 s at 1 Hz. -1 , and then the shear rate was linearly decreased from 100 to 0.01 s at 1 Hz. -1 The measurement time for each sample was 1 hour. To determine the viscosity, 2 measurement points were used. Point 3 at 6.26 Hz with a shear rate increase from 0.01 to 100 s -1 (upward), point 31 at 6.26 Hz the shear rate decreases from 100 to 0.01 s- 1 The results are shown in Table 5.

[0126] Table 5. Yogurt viscosity after 7 days of fermentation (mPas)

[0127]

[0128]

[0129] The viscosity of the yogurt containing 3 wt% IMMP fibers was about 2 times higher than the viscosity of the yogurt without any fiber. This effect was slightly more pronounced for IMMP-87 compared to IMMP-96. In contrast, the addition of 3w% VitaFiber fibers or Frutafit TEX! fibers had no significant effect on the viscosity of the yogurt compared to the yogurt without soluble fiber.

[0130] Example 4: Effect of IMMP concentration on yogurt viscosity

[0131] In this example, the effect of supplementation with IMMP (content of α(1→6) bonds of about 87%) on yogurt viscosity was evaluated within a certain range of IMMP concentrations.

[0132] Yogurt was prepared as follows. Fresh milk was weighed and added to the Thermomix. Dry ingredients were added gently to prevent lumps and splashing. The mixture was heated to 40°C and stirred at speed 3 for 10 minutes to hydrate. After hydration, it was heated to 85°C for 5 minutes and then cooled to 40°C in a stainless steel beaker. The starter culture stock solution was added similarly to Example 2, the mixture was transferred to a container, and it was fermented in a greenhouse at 30°C for 1 night. After fermentation, the pH value was less than 4.6. To prepare stirred yogurt, the yogurt was homogenized with IKA Magic at 3000rpm, filled into containers and stored in a refrigerator. Set yogurt was stored in a refrigerator after fermentation without homogenization. The amounts and sources of the ingredients are shown in Table 6. Delvo starter culture (DSM, batch FVV-221) was used.

[0133] Table 6. Ingredients used to prepare yogurts with different levels of IMMP-87

[0134]

[0135] Brookfield viscosity was measured after 1, 7 and 14 days at refrigerator temperature between 4 and 6° C. using a Brookfield DV2 with a lifting spindle at 10 rpm. The results for set yogurt and stirred yogurt are summarized in Tables 7a and 7b, respectively.

[0136] Table 7a. Dependence of Brookfield viscosity (mPas) of set yogurt on IMMP-87 concentration

[0137] IMMP-87 0％ 1.5％ 3％ 6％ time 24 hours 84300 89200 92200 100600 7 days 83400 91600 96400 100200 14 days 74200 90800 96200 108400

[0138] Table 7b. Dependence of Brookfield viscosity (mPas) of stirred yogurt on IMMP-87 concentration

[0139] IMMP-87 0％ 1.50％ 3％ 6％ time 24 hours 12300 13800 15900 18800 7 days 17400 - - 25600 14 days 16400 21300 19900 24500

[0140] From Tables 7a and 7b, it can be concluded that supplementation with IMMP-87 over a range of concentrations increased the viscosity of both set and stirred yogurts. For set yogurts, this effect was particularly evident after 7 or 14 days of storage. The increase in yogurt viscosity was dependent on the IMMP concentration, with higher concentrations resulting in higher viscosity.

[0141] Example 5: Comparison of IMMP with other slowly digesting and / or prebiotic fibers

[0142] In this example, regarding the effect on the Brookfield viscosity and storage modulus G' of chemically acidified milk gel, IMMP fibers having an α(1→6) bond content of 96% were compared with exemplary fibers. and VitaFiber TM Make a comparison.

[0143] Acid milk gels were prepared as follows. A skim milk powder stock solution was prepared by dissolving 290 g skim milk powder (Elk, Friesland Campina) in 710 ml demineralized water. Simulated milk ultrafiltration solutions SMUF and SMUF* were prepared according to the recipe in Table 8a. A stock solution containing 30 wt% fibers in SMUF* solution was prepared, including IMMP-96, or VitaFiber TM , where the moisture content of the fiber is taken into account. According to the recipe in Table 8b, 100 ml of acid milk gel solution was prepared by mixing the three stock solutions at a temperature of 30°C and adding glucono delta-lactone. After incubation for 17 hours, the acid milk gel was poured into 50 g plastic jars and stored at 4°C for 7 days.

[0144] Table 8a. Simulated milk ultrafiltration (SMUF and SMUF*) solution formulations

[0145] SMUF SMUF* Monopotassium phosphate 3.16g 3.16g Tripotassium Citrate 2.40g 2.40g Sodium citrate dehydrate 3.58g 3.58g Potassium sulfate 0.36g 0.36g Potassium carbonate 0.60g 0.60g Potassium chloride 1.2g 1.2g Calcium chloride dihydrate 2.64g Magnesium chloride hexahydrate 1.30g Demineralized water 2L 1.96L

[0146] Table 8b. Formulation of acid milk gel containing 6 wt% fiber

[0147] Skim milk powder stock solution (g) 25.57 Fiber stock solution (g) 20 SMUF(g) 53.33 Glucono delta-lactone(g) 1.1

[0148] After 7 days, the Brookfield viscosity and storage modulus of the acid milk gels were measured.

[0149] Brookfield viscosity measurements were performed using LVDVI+ and LVDVII+ viscometers from Brookfield. The measurements were performed for 30 seconds at 6 rpm with LV spindle 2 and LV spindle 3 (S62 / S63). The average value over these 30 seconds was considered the viscosity (mPas).

[0150] The storage modulus G' was measured using a modular compact rheometer MCR 302SN81328338 and SN81464746 from Anton Paar with cup rotors CC27 SN23477 and SN32606. Prior to the measurement, the rheometer was heated for 300 s for 60 s. -1The solution was mixed at a rate of . Then, stress control measurements were performed over time at 1 Hz using a 1% strain (measured once per minute) over 17 hours. The temperature of all experiments was set at 30°C. Before starting the measurement, the sample was covered with paraffin oil to prevent evaporation. The results of these measurements are shown in Table 9.

[0151] Table 9. Brookfield viscosity (mPas) and storage modulus G' of acid milk gels containing 6 wt% fibers

[0152]

[0153] The Brookfield viscosity and storage modulus of the acid milk gel supplemented with 6% IMMP-96 increased significantly (2.4 and 2.9 times, respectively). Supplementation with 6 wt% of any other fiber did not significantly increase the Brookfield viscosity or storage modulus.

[0154] Example 6: Effect of IMMP concentration on acid milk gel viscosity

[0155] In this example, the effect of the concentration of IMMP fibers (content of α(1→6) bonds of about 96%) on the viscosity of chemically acidified acid milk gels was evaluated.

[0156] According to the formulation in Table 10, an acid milk gel was prepared as described in Example 5.

[0157] Table 10. Acidic milk gel formulations with different concentrations of IMMP-96

[0158]

[0159] After storage at 4° C. for 7 days, the Brookfield viscosity and storage modulus G′ of the acid milk gel were measured as described in Example 5. The results are shown in Table 11.

[0160] Table 11. Dependence of Brookfield viscosity (mPas) and storage modulus G' of acid milk gels on IMMP-96 concentration

[0161]

[0162] These results indicate that supplementation of acid milk gels with IMMP-96 over a range of concentrations resulted in higher storage modulus and higher viscosity. Both properties exhibited a roughly linear dependence on IMMP-96 concentration over the range measured.

[0163] Example 7: Effect of the content of α(1→6) glycosidic bonds in IMMP on yogurt viscosity

[0164] IMMPs with different contents of α(1→6) glycosidic bonds were prepared according to the procedure described in Example 1(iii). After termination of the reaction for 36 hours, an IMMP with 87% α(1→6) glycosidic bonds (IMMP-87) was obtained. By removing samples in advance, IMMPs with 70% or 77% α(1→6) glycosidic bonds (IMMP-70 and IMMP-77, respectively) were obtained.

[0165] To evaluate the effect of IMMP on yogurt viscosity, stirred yogurt was prepared as performed in Example 4. The amount of IMMP fiber was corrected for its moisture content (mc). Brookfield viscosity was measured at 10 rpm using a Brookfield DV2 with a lifting spindle after 7 and 14 days of storage at a refrigerator temperature of 4 to 6°C.

[0166] The results in Table 12 show that supplementation with IMMP having at least 70% α(1→6) glycosidic bonds increases the viscosity of stirred yogurt. The increase in viscosity is positively correlated with the α(1→6) content and the IMMP concentration.

[0167] Table 12: Yogurt formulations (A) and Brookfield viscosities (B) obtained using IMMPs with α(1→6) glycosidic bond contents of 87%, 77%, or 69%.

[0168] A

[0169]

[0170]

[0171]

[0172] References:

[0173] [1]SeaMende, "Concentration dependent effects of dextran on the physical properties of acid milk gels," Carb.Pol., vol.98, pp.1389-1396, 2013.

[0174] [2]DHSaLJPachekrepapol,“Effect of dextran and dextran sulfateon the structural and rheological properties of model acid milk gels,”J.DairySci.,Vols.%1van%22843-2852,p.98,2015.

[0175] [3]H.Leemhuis,J.Dobruchowska,M.Ebbelaar,F.Faber,P.Buwalda,M.van derMaarel,J.Kamerling and L.Dijkhuizen,“Isomalto / malto-polysaccharide,a novelsoluble dietary fiber made via enzymatic conversion of starch,”J.Agric.FoodChem.,vol.62,pp.12034-12044,2014.

[0176] [4]Y.Bai,R.van der Kraaij,A.Woortman,Z.Jin and L.Dijkhuizen,“Characterization of the 4,6-α-glucanotransferase GTFB enzyme ofLactobacillus reuteri 121isolated from inclusion bodies,”BMC Biotechnology,p.2015:15.

[0177] [5]Y.Bai,J.Gangoiti,B.Dijkstra,L.Dijkhuizen and T.Pijning,“Crystal structure of 4,6-α-glucanotransferase supports diet-driven evolution of GH70enzymes fromα-amylases in oral bacteria,”Structure,vol.25,25,pp.23,2012.

Claims

1. A method for providing a spoonable acidified dairy product, comprising the following steps: a) providing an α-glucan composition, said α-glucan composition comprising an isomalt / maltopolysaccharide IMMP having a branching degree of less than 5%, said isomalt / maltopolysaccharide being characterized by a content of α-1,6-glycosidic bonds of at least 70%, said IMMP having a 1.0*10 3 and 1.0*10 6 Molecular weight between Da; b) supplementing a dairy product with the α-glucan composition to provide a supplemented dairy product comprising at least 3 wt% IMMP; as well as c) Acidifying the supplemented milk product to a pH below 5.

2. The method according to claim 1, wherein: In step c) the supplemented milk product is acidified to a pH of 4.

6.

3. The method according to claim 1, wherein: The dairy product is selected from the group consisting of fresh milk from mammals, skimmed milk, and reconstituted milk powder.

4. The method according to any one of claims 1 to 3, wherein: The supplemented milk product comprises 3-12 wt% IMMP.

5. The method according to any one of claims 1 to 3, wherein: Step c) comprises the following steps: (c1) inoculating the supplemented milk product with at least one lactic acid producing microorganism; and (c2) fermentation.

6. The method according to claim 5, wherein: The lactic acid producing microorganism is selected from the group consisting of Lactobacillus sp., Leuconostoc sp., Lactococcus sp., Streptococcus sp. and Pediococcus sp.

7. The method according to claim 5, wherein: The lactic acid producing microorganism is selected from the group consisting of Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus bifidus, Lactobacillus bulgaricus and Streptococcus thermophilus.

8. The method according to any one of claims 1 to 3, wherein: Step c) comprises adding an amount of chemical acidulant to said supplemented milk product to obtain a final pH below 5.

9. The method according to claim 8, wherein: The chemical acidulant is an agent including one or more compounds selected from the group consisting of acetic acid, citric acid, lactic acid, malic acid, succinic acid, tartaric acid and glucono delta-lactone.

10. The method according to claim 9, wherein: The chemical acidulant is glucono delta-lactone.

11. Use of an α-glucan composition for increasing the viscosity and / or stability of an acidified dairy product, the α-glucan composition comprising an isomalt / maltopolysaccharide IMMP having a branching degree of less than 5%, the isomalt / maltopolysaccharide being characterized by a content of α-1-6-glycosidic bonds of at least 70%, the IMMP having a molecular weight of 1.0*10 3 and 1.0*10 6 The molecular weight between Da, The acidified dairy product comprises at least 3 wt% IMMP.

12. The method according to any one of claims 1 to 3 or the use according to claim 11, wherein The α-glucan composition comprises an IMMP having an α-1-6-glycosidic bond content of at least 70%, wherein the IMMP is a linear glucooligosaccharide of the general formula AB, a glucan comprising such a linear portion, or a mixture comprising different glucooligosaccharides of the general formula AB, wherein: (i) the bond between part A and part B is an α-1-6-glycosidic bond; (ii) part A comprises at least two consecutive α-1-6-glycosidic bonds; (iii) Moiety B comprises at least two consecutive α-1-4-glycosidic bonds.

13. The method or use according to claim 12, wherein Fraction A comprises isomalto-oligosaccharides having a degree of polymerisation of at least 4 glucose residues.

14. The method according to any one of claims 1 to 3 or the use according to any one of claims 11 to 13, wherein The α-glucan composition is obtained by treating a starch substrate with a debranching enzyme and a GTFB type 4,6-α-glucanotransferase.

15. The method or use according to claim 14, wherein The treatment with the debranching enzyme and the treatment with the GTFB type 4,6-α-glucanotransferase are carried out simultaneously.

16. The method or use according to claim 14, wherein The debranching enzyme is isoamylase EC 3.2.1.68 or pullulanase EC 3.2.1.

41.

17. The method or use according to claim 16, wherein The debranching enzyme is pullulanase.

18. The method or use according to claim 14, wherein The GTFB type 4,6-α-glucanotransferase is GTFB from Lactobacillus reuteri 121.

19. The method or use according to claim 14, wherein The starch substrate is selected from the group consisting of cereal starch; root or tuber starch; and leguminous starch.

20. The method or use according to claim 19, wherein The cereal starch is selected from corn starch, wheat starch, rice starch, barley starch or rye starch; the root or tuber starch is selected from cassava starch, sweet potato starch, arrowroot starch and potato starch; the leguminous starch is selected from pea starch and kidney bean starch.

21. The method according to any one of claims 1 to 3 or the use according to any one of claims 11 to 13, wherein The Brookfield viscosity of the acidified dairy product is in the range of 5000 mPa·s to 70000 mPa·s.

22. The method according to any one of claims 1 to 3 or the use according to any one of claims 11 to 13, wherein The acidified dairy product is yoghurt, curd or cheese.

23. The method or use according to claim 22, wherein The acidified dairy product is yogurt.

24. The method according to any one of claims 1 to 3 or the use according to any one of claims 11 to 13, wherein The acidified dairy product is Greek yogurt, quark or skim yogurt.

25. The method according to any one of claims 1 to 3 or the use according to any one of claims 11 to 13, wherein The acidified dairy product comprises 3 wt% to 12 wt% IMMP.

26. A spoonable acidified dairy product obtainable by the method of any one of claims 1-10 or 12-25.

27. A spoon-type acidified dairy product, comprising at least 3 wt% of isomalt / maltopolysaccharide IMMP with a branching degree of less than 5%, the isomalt / maltopolysaccharide having an α-1-6-glycosidic bond content of at least 70%, the IMMP having a 1.0*10 3 and 1.0*10 6 Molecular weight between Da.

28. The spoonable acidified dairy product according to claim 27, wherein The IMMP comprises a linear oligoglucosaccharide of the general formula AB, a glucan comprising such a linear portion, or a mixture comprising different oligoglucosaccharides of the general formula AB, wherein: (i) the bond between part A and part B is an α-1,6-glycosidic bond; (ii) part A contains two or more consecutive α-1,6-glycosidic bonds; (iii) Moiety B comprises at least two consecutive α-1,4-linked glucose residues.

29. The spoonable acidified dairy product according to claim 28, wherein Fraction A comprises isomalto-oligosaccharides having a degree of polymerisation of at least 4 glucose residues.

30. The spoonable acidified dairy product according to any one of claims 27 to 29, wherein The spoonable acidified dairy product has a Brookfield viscosity ranging from 5000 mPa·s to 70000 mPa·s.

31. The spoonable acidified dairy product according to any one of claims 27 to 29, wherein The spoon-type acidified dairy product is yogurt, curd or cheese.

32. The spoonable acidified dairy product according to claim 31, wherein The spoon-type acidified dairy product is yogurt.

33. The spoonable acidified dairy product according to any one of claims 27 to 29, wherein The spoonable acidified dairy product is Greek yogurt, quark or skim yogurt.

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