Processing aid comprising encapsulated sour dough lactic acid bacteria for preparing baked product dough

Abstract

The invention relates to an aid for preparing a baked food dough. The adjuvant comprises a food grade carrier and microcapsules containing live lactic acid bacteria belonging to at least one species encapsulated in a shell comprising at least one gelling biopolymer. Microcapsules are dispersed in the food grade flour and have an average size of 350 [mu] m to 550 [mu] m, preferably 390 [mu] m to 490 [mu] m, more preferably 400 [mu] m to 460 [mu] m, and a mechanical compressive strength of 3200 g to 9000 g, preferably 3400 g to 6000 g, more preferably 3500 g to 5700 g. The invention also relates to a microencapsulation method, a production method and a use of such an additive, as well as a dough, a preparation method of a baked food using such an additive, and a baked food obtained by the preparation method.

Description

Technical Field

[0001] The present invention relates to a processing aid for preparing dough for baked products, and a related production method and use.

[0002] The present invention also relates to dough containing the processing aid, baked food and a production method using the processing aid.

[0003] The invention also relates to a method for microencapsulating live lactic acid bacteria, and obtains microcapsules for producing the above-mentioned processing aid. Background Art

[0004] Lactic acid bacteria are widely used in the food industry. They are responsible for the fermentation of many foods, such as dairy products, bakery products, fermented meat or vegetables. Due to their metabolic activity, lactic acid bacteria are able to transform raw materials and give foods specific rheological and organoleptic characteristics.

[0005] In the field of baked goods production, lactic acid bacteria are often used together with or instead of yeast in the preparation of dough. Lactic acid bacteria are contained in so-called sourdough or sourdough starter, a mixture of water and flour, in which spontaneous fermentation occurs, forming and maintaining a complex biological ecosystem, depending on the environment, the raw materials used and the production method. The dominant microflora of sourdough consists of lactic acid bacteria associated with yeast, usually in smaller numbers than lactic acid bacteria.

[0006] The use of sourdough imparts favorable rheological and shelf life characteristics to the dough and better organoleptic qualities to the final product. The fermentation of sugars by the lactic acid bacteria present in the sourdough produces organic acids such as lactic acid and, in the case of obligate heterofermentative lactic acid bacteria, acetic acid as well as carbon dioxide. Lactic acid bacteria can also produce polysaccharides, degrade proteins in the flour due to their enzymatic activity and produce volatile compounds that give the product a complex and characteristic aromatic profile.

[0007] The preparation of traditional sourdough (also known in the industry as type 1 sourdough) starts with a spontaneous sourdough obtained from a mixture of water and flour that is left to sour spontaneously for a longer or shorter period of time. The fermentation and subsequent rise of the dough are initiated by lactic acid bacteria naturally present in the flour and in the environment. The spontaneous sourdough can be renewed regularly by subsequent remixing with water and flour in doses adapted to the characteristics of the dough.

[0008] This type of preparation leads to the chaotic and uncontrolled development of various microbial species, not always with positive characteristics, which are spontaneously selected during the fermentation process as the acidity of the mixture increases and the oxygen and sugar content decreases. In general, unwanted organisms are inactivated, but the variability of the microbial community does not usually allow its characteristics to be preserved for a long time, sometimes making the technological properties of natural sourdough yeast unstable and difficult to control. This, together with the laborious handling of sourdough, the long fermentation times and the delicate storage, means that its use is limited to household or at most small-scale industrial production.

[0009] Related technologies

[0010] In order to replicate the properties of spontaneously fermented semi-finished products or foods, such as the above-mentioned sourdough-based dough, or to impart special functional or organoleptic properties to foods, it is technically known to incorporate live lactic acid bacteria into raw materials (such as flour, milk, meat, etc.), semi-finished products or foods, or additives or processing aids for the preparation of such semi-finished products or foods.

[0011] However, there are several key issues in the industrial-scale application of lactic acid bacteria, first of all the need to maintain the activity of the microorganisms and finally the use of additives, processing aids, semi-finished products or foods in which these bacteria are dispersed.

[0012] To address these problems, microencapsulation technology, known in the industry, incorporates living bacterial cells into small capsules of food-grade polymeric materials.

[0013] For example, document KR20160051902A discloses a composition comprising lactic acid bacteria embedded in alginate beads.

[0014] The alginate beads are produced by mixing lactic acid bacteria with an aqueous alginate solution and adding the solution dropwise to a calcium chloride solution to harden the beads. The resulting beads are dried by freeze drying.

[0015] The document points out that freeze drying as a method for drying capsules containing lactic acid bacteria will damage the activity of the bacteria, and the survival rate after drying is only 60%-70%. In order to overcome this disadvantage and increase the survival rate of bacteria, various cryoprotectants are used, such as soy flour, sugar, amino acids, peptides, gelatin, glycerol, sugar alcohols, whey, alginic acid, ascorbic acid, yeast extract, skim milk, trehalose, garlic extract.

[0016] Applicants note that freeze drying is a complex and expensive drying technique, and is quite energy inefficient. The process requires subjecting the material to be dried to very low temperatures under high vacuum conditions for several days. These and other key issues make the technique difficult to scale up at an industrial level.

[0017] Freeze drying also has a significant impact on the activity of encapsulated microorganisms. To address this issue, KR20160051902A relies on the use of cryoprotectants, however, as the document itself admits, changes the taste, texture and / or production cost of the food using the disclosed lactic acid bacteria composition, which may make them unsuitable for preparing many foods.

[0018] It should also be noted that this document does not focus on the textural, organoleptic and nutritional characteristics of the finished product obtained from the composition comprising microcapsules, characteristics which are of particular importance, in the Applicant's opinion, especially when lactic acid bacteria are used in the preparation of baked goods with the aim of reproducing the fermentation effect promoted by natural sourdough yeast. Summary of the invention

[0019] In view of the problems encountered in the prior art, the general object of the present invention is to provide a food additive comprising microencapsulated lactic acid bacteria, which has a high degree of time stability, in particular, can keep the activity of the lactic acid bacteria substantially unchanged when stored at room temperature for at least six months.

[0020] More specifically, the applicant's object is to provide a food additive comprising a capsule structure configured to maintain the activity of microorganisms during storage, while allowing easy release and rapid dispersion of the microorganisms in the dough when an adjuvant is added to the dough during mixing.

[0021] Another object of the present invention is to provide a food additive for preparing dough for baked goods, which food additive enables the preparation of products having better organoleptic and nutritional qualities, longer shelf life and better structure than products prepared with known processing aids and comparable to products prepared with natural leavened dough yeast.

[0022] The Applicant has also set itself the object of providing a food aid comprising microcapsules containing lactic acid bacteria which can be obtained by a simplified, more economical process and which does not require the use of protective additives, such as cryoprotectants, during the step of drying the microcapsules.

[0023] With these objectives in mind, the present inventors have recognized and experimentally discovered that by providing microcapsules with appropriate chemical-physical, mechanical and geometrical properties, their resistance to rupture during storage and subsequent use can be appropriately adjusted.

[0024] Thus, the present invention in its first aspect relates to a processing aid for preparing a dough for baked goods, comprising food grade flour and microcapsules dispersed in the food grade flour.

[0025] The microcapsules comprise live lactic acid bacteria encapsulated in a shell comprising at least one gellable biopolymer and have an average size D50 of 350 to 550 μm, preferably 390 to 490 μm, more preferably 400 to 460 μm. The microcapsules also have a mechanical compressive strength of 3200 to 9000 g, preferably 3400 to 6000 g, more preferably 3500 to 5700 g, measured as detailed in Example 4.

[0026] According to a second aspect of the present invention, in the context of solving the proposed technical problem presented above, the present invention further relates to a method for microencapsulation of live lactic acid bacteria in a shell comprising at least one gellable biopolymer.

[0027] The method includes:

[0028] a) providing a solution comprising a gellable biopolymer and live lactic acid bacteria;

[0029] b) adding droplets of the solution of the gellable biopolymer and live lactic acid bacteria to a gelling bath comprising at least one gelling agent and causing the droplets to gel, and

[0030] c) drying the gelled droplets by air drying to obtain microcapsules containing live lactic acid bacteria belonging to at least one species, said microcapsules having an average size D50 of 350 to 550 μm, preferably 390 to 490 μm, more preferably 400 to 460 μm, and having a mechanical compressive strength of 3200 to 9000 g, preferably 3400 to 6000 g, more preferably 3500 to 5700 g, measured as detailed in Example 4.

[0031] According to a third aspect of the present invention, in the context of solving the proposed technical problem presented above, the present invention further relates to a method for producing an auxiliary for preparing baked goods.

[0032] The method includes:

[0033] x) providing microcapsules containing live lactic acid bacteria belonging to at least one species encapsulated in a shell comprising at least one gellable biopolymer, said microcapsules having an average size of 350 to 550 μm, preferably 390 to 490 μm, more preferably 400 to 460 μm, and having a mechanical compressive strength of 3200 to 9000 g, preferably 3400 to 6000 g, more preferably 3500 to 5700 g, measured as detailed in Example 4, by a microencapsulation method according to the second aspect of the invention; and

[0034] y) dispersing the microcapsules in a certain amount of a food grade carrier for baked food.

[0035] According to a fourth aspect of the present invention, in the context of solving the technical problems presented above, the present invention further relates to a dough for baked food comprising the auxiliary agent according to the first aspect of the present invention, water and optionally other raw materials.

[0036] According to a fifth aspect of the present invention, in the context of solving the technical problems outlined above, the present invention also relates to a method for preparing a baked product, comprising:

[0037] - forming a slurry by mixing the adjuvant according to the first aspect of the invention with water and optionally other raw materials (such as flour),

[0038] -Optionally, divide the dough into several portions;

[0039] - optionally, giving the dough or dough portion a desired shape; and

[0040] - Bake the dough or dough portions in an oven.

[0041] According to a sixth aspect of the present invention, in the context of solving the technical problems presented above, the present invention also relates to a baked food obtained by the preparation method according to the fifth aspect of the present invention.

[0042] According to a seventh aspect, the present invention further relates to the use of the auxiliary agent according to the first aspect in preparing dough for baked goods.

[0043] According to another non-claimed aspect, the present invention further relates to the use of a processing aid according to the first aspect of the present invention in a direct kneading process for producing a baked food product according to the third aspect of the present invention.

[0044] Applicants have surprisingly found that the processing aids of the present invention impart organoleptic, rheological and textural properties to baked products made therewith, or a texture similar to that of products made from sourdough.

[0045] Without wishing to be bound by any theory of explanation, the inventors believe that the positive effects of improving the sensory, rheological and structural properties or texture of the baked goods can be attributed to the above-mentioned combination of size characteristics and mechanical strength of the microcapsules.

[0046] In particular, the inventors believe that the above size and mechanical strength values ​​are an optimal compromise so that the microcapsules can remain intact and preserve the lactic acid bacteria in the absence of mechanical stress and in a dry environment, and the microcapsules can open quickly when exposed to typical mechanical stresses in dough preparation, whether applied manually or mechanically by a kneading machine, as well as the moist environment of the dough.

[0047] The applicant also believes that the size of the microcapsules obtained according to the microencapsulation method of the present invention is smaller than that disclosed in the known art mentioned herein, which facilitates their dispersion and uniform distribution in the dough during mixing.

[0048] The inventors have surprisingly found through experiments that the use of an air drying step in the microencapsulation method according to the invention results in microcapsules having the aforementioned advantageous size and mechanical strength characteristics.

[0049] The inventors have also found that, in addition to producing microcapsules containing lactic acid bacteria suitable for imparting improved properties to baked food dough, the microencapsulation method according to the present invention is simpler, cheaper and easier to scale up than known microencapsulation methods (such as the method disclosed in KR20160051902A including a freeze-drying step).

[0050] The inventors also found through experiments that the activity of the lactic acid bacteria encapsulated in the microcapsules remained substantially unchanged for at least six months of storage of the processing aid. It was unexpectedly found that the activity of the lactic acid bacteria remained unchanged even when the processing aid was stored at room temperature or at a temperature (about 28-30° C.) at which baked food dough is usually processed, indicating the high stability of the processing aid of the present invention.

[0051] Specific implementation of the currently preferred embodiment of the present invention

[0052] In one or more aspects of the invention, the invention may include one or more of the preferred features outlined below, which features may preferably be combined with each other depending on the application requirements.

[0053] In the context of this specification and the claims that follow, "baked food" means any savory or sweet product obtained by baking in whole or in part a leavened and / or fermented dough obtained by mixing a food grade flour product with water and any additives or processing aids. As a non-limiting example, the term may refer to products such as bread, pizza, focaccia, biscuits, crackers, rusks, brioches, cakes and baked desserts, breadsticks, taralli.

[0054] In this specification and the subsequent claims, the terms "direct kneading method / process" and "indirect dough method / process" are used with their ordinary meaning in the field of baked food preparation. In particular, "direct dough making method / process" refers to a method / process for preparing dough for baked food, in which all raw materials are added together or one by one in sequence and kneaded immediately. In contrast, "indirect dough method / process" refers to a method / process in which a pre-dough is prepared with only part of the raw materials, the dough is left to rest for a predetermined time, which can be from a few minutes to a few hours, and then the remaining raw materials are added.

[0055] In the context of this specification and the claims that follow, "added enzymes" refer to enzymes and additional enzymes that are different from the enzymes present in the processing aid and / or the mixture to which such processing aid is added, possibly produced exogenously by the metabolism of microorganisms, in particular lactic acid bacteria, and are added to the processing aid during its production, before the processing aid is used in the dough.

[0056] In the context of the present specification and the subsequent claims, the expression "mean size D50" used with respect to microcapsules refers to the 50% percentile diameter relative to the microcapsule size distribution. D50 is defined as the value below which 50% of the microcapsules in the size distribution have a diameter.

[0057] In the context of the present specification and the subsequent claims, the expression "mean size D10" used with respect to microcapsules refers to the percentile diameter relative to 10% of the microcapsule size distribution. D10 is defined as the value below which 10% of the microcapsules in the size distribution have a diameter.

[0058] In the context of the present specification and the subsequent claims, the expression "mean size D90" used with respect to microcapsules refers to the 90% percentile diameter relative to the microcapsule size distribution. D90 is defined as the value below which 90% of the microcapsules in the size distribution have a diameter.

[0059] In the context of this specification and the claims that follow, an "effective amount of an enzyme" refers to the minimum amount that enables the enzyme to perform its specific action.

[0060] Throughout the present specification and the claims that follow, unless otherwise indicated, all numerical values ​​expressing quantities, parameters, percentages, etc., are in any case considered to be preceded by the term "about". Furthermore, unless otherwise indicated, all ranges of numerical values ​​are to be understood to include the extreme values ​​and, in addition to the ranges specifically indicated below, all possible combinations of maximum and minimum numerical values ​​and all possible intermediate ranges.

[0061] Preferably, the microcapsules contain lactic acid bacteria which can be isolated from natural sourdough yeast.

[0062] More preferably, the microencapsulated lactic acid is a lactic acid bacteria isolatable from traditional sourdough yeast, also known in the industry as traditional or type 1 sourdough.

[0063] Applicants have found that baked products made with a processing aid comprising the lactic acid bacteria of the present invention which can be isolated from conventional sourdough yeast display a recognizable aroma, flavor and taste, which in the applicant's opinion is due to the release of a broad spectrum of characteristic volatile compounds such as acids, alcohols, aldehydes, ketones by the bacteria.

[0064] The applicant further pointed out that during the dough fermentation process, the presence of the lactic acid bacteria of the present invention promotes the production of lipolytic enzymes, which are able to decompose triglycerides and other lipids, releasing glycerol, fatty acids and other molecules with favorable emulsifying power, which helps to improve the quality and structure of the dough.

[0065] The applicant has also found that, due to a metabolic mechanism that has not yet been fully elucidated, the baked products obtained from the processing aid according to the present invention are advantageously subjected to a slowdown in the aging process and loss of freshness, and are preserved longer than the baked products obtained without the processing aid of the present invention. In particular, the applicant has found that the shelf life of the baked products obtained by using the processing aid of the present invention (assessed based on the starch retrogradation rate) is 30% or more longer than the shelf life of similar baked products obtained without the processing aid of the present invention.

[0066] Preferably, the lactic acid bacteria contained in the microcapsule belong to one or more species selected from the group consisting of Fructilactobacillus sanfranciscensis, Furfurilactobacillus rossiae, Lactiplantibacillus plantarum, Companilactobacillus alimentarius, Levilactobacillus brevis, Lentilactobacillus buchneri, Latilactobacillus curvatus, Lactobacillus delbrueckii, Limosilactobacillus fermentum, Limosilactobacillus frumenti, Levilactobacillus hammesii, Lactobacillus helveticus, helveticus), Lentilactobacillus hilgardii, Limosilactobacillus panis, Companilactobacillus paralimentarius, Lacticaseibacillus paracasei, Lactiplantibacillus paraplantarum, Lactiplantibacillus pentosus, Limosilactobacillus pontis, Limosilactobacillus reuteri, Latilactobacillus sakei, Lactococcus lactis, Leuconostoc citreum, Leuconostoc mesenteroides, Pediococcus pentosaceus pentosaceus, Weissella cibaria, and Weissella confusa.

[0067] More preferably, the lactic acid bacteria contained in the microcapsule belong to one or more species selected from the group consisting of Lactobacillus sanfranciscosa, Lactobacillus furfur, and Lactobacillus plantarum.

[0068] In a preferred embodiment of the present invention, the microcapsules contain a combination of lactic acid bacteria belonging to a species selected from the group consisting of Lactobacillus sanfranciscosa, Lactobacillus furfur and Lactobacillus plantarum.

[0069] In another preferred embodiment of the present invention, the processing aid comprises a combination of microcapsules, each microcapsule containing a lactic acid bacterium belonging to a species selected from the group consisting of Lactobacillus sanfranciscosa, Lactobacillus furfur and Lactobacillus plantarum.

[0070] In this case, the processing aid preferably comprises a first portion of microcapsules containing lactic acid bacteria belonging to the species Lactobacillus sanfranciscosa.

[0071] Preferably, the processing aid further comprises a second part of microcapsules containing lactic acid bacteria belonging to the species Lactobacillus furfur.

[0072] Preferably, the processing aid further comprises a third part of microcapsules containing lactic acid bacteria belonging to the species Lactobacillus plantarum.

[0073] Lactic acid bacteria belonging to the species Lactobacillus sanfrancisco, Lactobacillus furfur, and Lactobacillus plantarum are part of the microbiota of many traditional type 1 sourdoughs. In particular, Lactobacillus sanfrancisco and Lactobacillus plantarum are considered to be dominant sourdough species as they are reported to be present in approximately 50% of sourdoughs ( et al. 2016, [1]). In addition, Lactobacillus furfur is widely distributed in sourdoughs, especially those produced in Italy (Settanni et al. 2005, [2]).

[0074] Lactobacillus sanfrancisco is an obligate heterofermentative bacterial species that efficiently metabolizes maltose and is therefore well suited for sourdough environments. Lactobacillus sanfrancisco produces heteropolysaccharides (EPS) that positively affect the volume, texture and general rheological properties of baked goods. Lactobacillus sanfrancisco also produces metabolites such as phenylacetic acid (PLA) that can inhibit fungal growth and contribute to the flavor definition of baked goods through the metabolism of maltose and amino acids. Other technologically relevant characteristics of strains of this species may be the increased bioavailability of minerals and bioactive compounds, as well as the ability to degrade gluten (Zhang et al. 2019, [3]).

[0075] Lactobacillus plantarum is a facultative heterofermentative species that produces antifungal compounds, thereby improving the shelf life of baked goods (Ventimiglia et al. 2015, [4]). In sourdough, Lactobacillus plantarum is important for acid production: it ferments hexoses to lactic acid via the homolactic pathway and degrades pentoses via the pentose phosphate pathway to produce lactic and acetic acid. Some Lactobacillus plantarum strains also have extracellular protease activity that can positively influence the rheological and sensory properties of the product.

[0076] Lactobacillus furfur is an obligate heterofermentative bacterial species that is also highly adapted to the sourdough environment. Strains belonging to this species show interesting technological properties such as acidification capacity and peptidase activity (Di Cagno et al. 2007, [5]).

[0077] The Applicant has observed that the above-mentioned Lactobacillus species, in particular Lactobacillus sanfranciscosifolius and Lactobacillus plantarum, are particularly effective in releasing a broad spectrum and high amount of volatile compounds that have a positive impact on the aromatic quality of baked products.

[0078] Preferably, the processing aid also includes an effective amount of at least one added enzyme.

[0079] Preferably, the processing aid comprises the at least one added enzyme in an amount of 0.01 g / kg to 5 g / kg of processing aid.

[0080] In a preferred embodiment, the at least one added enzyme is selected from xylanases, transglutaminases, cellulases, amylases, amyloglucosidases, lipases, phospholipases, asparaginases, oxidases of fungal or bacterial origin, or mixtures thereof.

[0081] Preferably, the at least one added enzyme is of the hydrolytic type.

[0082] Preferably, the at least one added enzyme is non-proteolytic.

[0083] More preferably, the at least one added enzyme comprises a xylanase that can hydrolyze arabinoxylan to produce xylose.

[0084] Arabinoxylans are branched polysaccharides built from pentose sugars (arabinose and xylose) located in the cell walls of the starchy endosperm, in the bran tissue, and in the husks of different types of cereals. Specially selected xylanases increase the availability of soluble fermentable sugars in the dough by breaking the arabinoxylan chains and generating xylose.

[0085] This increased availability of sugars positively affects the metabolism of xylose-fermenting lactic acid bacteria, especially those with heterofermentative metabolism. Compared to the fermentation of glucose and maltose (hexoses), the fermentation of pentoses such as xylose is more favorable for these microorganisms from an energetic point of view, with a positive effect on the acidification rate of the dough and the release of volatile compounds.

[0086] Able to freely exert their metabolic activity, even with a greater competitive advantage than yeast used for bread leavening, lactic acid bacteria confer on baked goods high-quality sensory, nutritional and textural properties or texture comparable to those observed in products made from natural sourdough.

[0087] Preferably, the food-grade carrier for baked goods comprises one or more of soft wheat flour, hard wheat flour, corn flour, rice flour, spelt flour, oat flour, pea flour, chickpea flour, soy flour, rye flour, millet flour, flaxseed flour, sesame flour, sunflower seed flour, gluten, corn starch, dry sourdough, brewer's yeast, salt or a mixture thereof.

[0088] Preferably, additional raw materials used in preparing the dough may include food grade flour, salt, yeast, sugar, fat and baking additives or adjuvants.

[0089] Preferably, the gellable biopolymer and live lactic acid bacteria solution are aqueous solutions.

[0090] Preferably, the gelling biopolymer of the microcapsule shell is selected from starch or its derivatives, sodium alginate, calcium alginate, potassium alginate, ammonium alginate, gellan gum, xanthan gum, milk protein, gelatin or mixtures thereof.

[0091] In a particularly preferred embodiment of the present invention, the gellable biopolymer of the microcapsule shell is sodium alginate.

[0092] Sodium alginate is a water-soluble polysaccharide isolated from the cell wall of algae, composed of two monomer units, mannuronic acid and guluronic acid. It has a negative overall charge, and when exposed to multivalent cations such as calcium ions, the carboxylic acid groups on the guluronic acid monomers interact with the multivalent cations to form a cross-linked hydrogel. Advantageously, the polymerization can be carried out at room temperature and does not require a heating step, which would negatively affect the activity of the microorganisms to be microencapsulated.

[0093] Preferably, the sodium alginate used according to the present invention has a viscosity of 4 to 12 mPa·s when dissolved in a 1 wt % aqueous solution at a temperature of 20°C.

[0094] Alginates with the above viscosity values ​​are referred to as low viscosity alginates. Low viscosity alginates exhibit high solubility, ie, high concentrations of alginate (up to 15-20 wt%) can be dissolved in aqueous solution while maintaining a viscosity of the resulting solution suitable for processing to form microcapsules.

[0095] The high concentration of alginate in the encapsulation solution used during the microencapsulation of the lactic acid bacteria means that the alginate walls of the microcapsules confining the lactic acid bacteria are thicker and stronger, thus providing greater protection and survival potential for the microorganisms.

[0096] Preferably, the processing aid according to the first aspect of the present invention can be obtained by microencapsulating live lactic acid bacteria belonging to at least one species in a shell formed by a gellable biopolymer and a solution of live lactic acid bacteria, the solution comprising sodium alginate having a viscosity within the above preferred values ​​when dissolved in a 1 wt % aqueous solution at 20°C.

[0097] Preferably, the concentration of sodium alginate in the solution of gellable biopolymer and live lactic acid bacteria is from 3 to 20 wt %, more preferably from 3 to 15 wt %, even more preferably from 4 to 7 wt %.

[0098] Preferably, the concentration of sodium alginate in the solution of gellable biopolymer and live lactic acid bacteria is greater than 1 wt%, more preferably greater than 2 wt%, even more preferably greater than 3 wt%, even more preferably greater than 4 wt%, even more preferably greater than 5 wt%, even more preferably greater than 6 wt%, even more preferably greater than 7 wt%, even more preferably greater than 8 wt%, even more preferably greater than 9 wt%, even more preferably greater than 10 wt%.

[0099] Preferably, the concentration of sodium alginate in the solution of gellable biopolymer and live lactic acid bacteria is less than 20 wt%, more preferably less than 19 wt%, even more preferably less than 18 wt%, even more preferably less than 17 wt%, even more preferably less than 16 wt%, even more preferably less than 15 wt%, even more preferably less than 14 wt%, even more preferably less than 13 wt%, even more preferably less than 12 wt%, even more preferably less than 11 wt%, even more preferably less than 10 wt%, even more preferably less than 9 wt%, even more preferably less than 8 wt%, even more preferably less than 7 wt%, even more preferably less than 6 wt%, even more preferably less than 5 wt%.

[0100] Preferably, the processing aid according to the first aspect of the present invention is obtainable by microencapsulating live lactic acid bacteria belonging to at least one species in a shell formed of a solution of a gellable biopolymer and live lactic acid bacteria, the solution comprising sodium alginate at a concentration within the above preferred numerical range.

[0101] Experiments carried out by the Applicant have demonstrated that the use of alginates, in particular sodium alginate, with the above-mentioned viscosity and concentration values ​​in a solution of a gellable biopolymer and lactic acid bacteria makes it possible to obtain microcapsules having dimensions and mechanical properties within the ranges described above and in the claims.

[0102] Preferably, the gelling bath is an aqueous solution and the at least one gelling agent comprises one or more divalent cations, such as calcium ions from the dissolution of calcium chloride.

[0103] Preferably, said step a) of preparing a solution of a gellable biopolymer and live lactic acid bacteria comprises forming an aqueous solution of the gellable biopolymer, adding the lactic acid bacteria and mixing until homogenized.

[0104] Preferably, the concentration of lactic acid bacteria in the solution of gellable biopolymer and live lactic acid bacteria is from 0.4 to 25 wt%, more preferably from 0.4 to 20 wt%, even more preferably from 0.5 to 20 wt%.

[0105] Preferably, the lactic acid bacteria are provided in the form of fresh concentrated biomass in aqueous suspension, fresh concentrated biomass stored in frozen form or biomass in freeze-dried form, which can be stored at room temperature, under refrigeration or frozen.

[0106] When the lactic acid bacteria are supplied as fresh or freeze-dried biomass stored in frozen form, a lactic acid bacteria thawing step is provided.

[0107] Preferably, the microcapsules have a relative humidity of 10% to 17%, more preferably 11% to 16%, even more preferably 12% to 15.5%.

[0108] Preferably, the microcapsules have an average size D10 of 200 μm to 320 μm, more preferably of 230 μm to 300 μm, even more preferably of 260 μm to 280 μm.

[0109] Preferably, the microcapsules have an average size D90 of 580 μm to 1000 μm, more preferably of 600 μm to 850 μm, even more preferably of 620 μm to 770 μm.

[0110] Preferably, the microcapsules have a bulk density of 0.35 g / mL to 0.55 g / mL, more preferably 0.4 g / mL to 0.5 g / mL, even more preferably 0.45 g / mL to 0.48 g / mL, the bulk density being assessed on the bulk mass of the uncompressed microcapsules and defined as the ratio of the weight to the volume (including voids) of a reference amount of microcapsules.

[0111] Preferably, the microcapsules have a tap density of 0.45 g / mL to 0.7 g / mL, more preferably 0.55 g / mL to 0.65 g / mL, even more preferably 0.58 g / mL to 0.6 g / mL, the tap density being assessed on the compacted volume mass of the microcapsules and defined as the ratio of the weight to the volume of a reference amount of microcapsules after compaction as detailed in Example 3.

[0112] Preferably, said step b) of adding droplets of the gellable biopolymer solution and live lactic acid bacteria to the gelling bath comprises extruding the droplets through a preferably vibrating type nozzle.

[0113] In a preferred embodiment, said step c) of air drying the gelled droplets is performed in an oven with forced air circulation or convection.

[0114] Preferably, the forced air circulation oven comprises one or more support trays for the microcapsules, an electrical coil configured to heat air within an interior chamber of the oven, and a fan configured to move the heated air within the chamber.

[0115] Preferably, such a forced air oven comprises an outlet at the rear configured to release moisture laden air and an outlet system for exhaust air.

[0116] In another preferred embodiment, said step c) of air drying the gelled droplets is carried out in a vibrating fluidized bed dryer.

[0117] Preferably, such a vibrating fluid bed dryer comprises a container containing a plurality of microcapsules, the microcapsules being vibrated by special vibrating elements, and a stream of hot air being conveyed through the plurality of microcapsules into the container as the microcapsules are moved by the vibration of the container.

[0118] The use of this method results in a particularly gentle and uniform drying of the microcapsules.

[0119] Other features of the present invention will be demonstrated in the following examples.

[0120] Example 1 - Preparation of air-dried microcapsules

[0121] Lactic acid bacteria belonging to strains of the species Lactobacillus sanfrancisco (SF), Lactobacillus plantarum (PL) and Lactobacillus furfur (RO) stored in the form of frozen freeze-dried biomass were thawed by immersing the individual tubes in a bath at room temperature.

[0122] After thawing, 2.5 g of biomass of each strain was suspended in 200 g of sterile deionized water under stirring, and the pH was controlled in the range of 4.5-5.2.

[0123] The bacterial suspension of the above three lactobacilli was then added to an encapsulation aqueous solution containing 7 wt % sodium alginate extracted from brown algae (BR-L alginate), which has a viscosity of 4 to 12 mPa·s when dissolved in an aqueous solution at 1 wt % at 20°C.

[0124] A solution of gellable biopolymer and live lactic acid bacteria was then obtained for subsequent droplet extrusion in the amounts shown in Table 1 below.

[0125] Table 1 - Composition of gellable biopolymer solution and live lactic acid bacteria for subsequent extrusion

[0126] Material quantity Weight Percent Lactic acid bacteria 2.5g 0.5％ BR-L Alginate 20g 4％ Sterile deionized water 477.5g 95.5％ Total solution 500g 100％

[0127] Table 2 below shows the pH and viscosity values ​​of the resulting solutions of the gellable biopolymer and the live lactic acid bacteria obtained from each strain.

[0128] Table 2 - pH and viscosity of gellable biopolymer and live lactic acid bacteria solutions

[0129] Solutions of gellable biopolymers and live lactic acid bacteria pH Viscosity Lactic acid bacteria SF solution 6.2 59mPa·s at 25.5℃ Lactic acid bacteria PL solution 6.5 65mPa·s at 24℃ Lactic acid bacteria RO solution 6 57mPa·s at 29.6℃

[0130] Each solution of gellable biopolymer and live lactic acid bacteria thus obtained was first sieved through an 80 μm sieve to remove any unwanted aggregates and then extruded into droplets using a vibrating nozzle with an outlet diameter of 350 μm (500 Hz, 2750 mV, 150 mBar) and the droplets were dropped into a gelling bath containing divalent ions from calcium chloride and optionally polyethylene glycol with an average molecular weight of 1500, the amount of polyethylene glycol being specified in Table 3.

[0131] Table 3 - Gelling bath composition

[0132] Material quantity Weight Percent <![CDATA[CaCl2]]> 100g 2％ PEG 1500 (optional) 50g 1％ Sterile deionized water 4850g 97％ Total Gelling Bath 5000g 100％

[0133] The droplets were left in the gelling bath, producing gelled droplets with an average size of 800 μm and 1000 μm.

[0134] The resulting gelled droplets were washed with 0.85% NaCl solution and then treated with a SiO2 anti-caking agent.

[0135] Finally, the gelled droplets were dried in a forced circulation drying oven with the air temperature set at 30°C until the relative humidity of the microcapsules reached 12% and 15.5%, obtaining a combination of microcapsules, each microcapsule containing lactic acid bacteria of a species selected from Lactobacillus sanfranciscosi, Lactobacillus plantarum and Lactobacillus furfur.

[0136] Similar results were obtained with respect to the characteristics of the gellable biopolymer and the lactic acid bacteria solution (Tables 1 and 2) by mixing the above three lactic acid bacteria strains in the process of forming the gellable biopolymer and the lactic acid bacteria solution, and the method finally obtained microcapsules each of which contained a combination of the three strains.

[0137] Example 2 (Comparative) - Preparation of Freeze-dried Dry Microcapsules

[0138] Lactic acid bacteria belonging to strains of the species Lactobacillus sanfrancisco (SF), Lactobacillus plantarum (PL) and Lactobacillus furfur (RO) stored in the form of frozen freeze-dried biomass were thawed by immersing the individual tubes in a bath at room temperature.

[0139] After thawing, 2.5 g of biomass of each strain was suspended in 200 g of sterile deionized water under stirring, and the pH was controlled in the range of 4.5-5.2.

[0140] The bacterial suspension was then added to an encapsulation aqueous solution containing 7 wt % sodium alginate extracted from brown algae (BR-L alginate), which has a viscosity of 4 to 12 mPa·s when dissolved at 1 wt % in aqueous solution at 20°C.

[0141] A solution of gellable biopolymer and live lactic acid bacteria was then obtained for subsequent droplet extrusion, having the same composition as shown in Table 1 above.

[0142] The pH and viscosity values ​​of the resulting solutions of gellable biopolymers and live lactic acid bacteria obtained from each strain were the same as those provided in Table 2 above.

[0143] Each solution of gellable biopolymer and live lactic acid bacteria thus obtained was first sieved through an 80 μm sieve to remove any unwanted aggregates and then extruded into droplets using a vibrating nozzle with an outlet diameter of 350 μm (500 Hz, 2750 mV, 150 m Bar) and the droplets were dropped into a gelling bath containing divalent ions from calcium chloride and optionally polyethylene glycol with an average molecular weight of 1500, the amount of polyethylene glycol being specified in Table 3 above.

[0144] The droplets are left in the gelling bath, producing gelled droplets having an average size of approximately 800 to 1000 μm.

[0145] The resulting gelled droplets were washed with 0.85% NaCl solution, frozen in liquid nitrogen, and stored at -40°C before lyophilization.

[0146] The gelled droplets were then freeze-dried at -7°C for 74 hours to obtain a combination of microcapsules, each microcapsule containing lactic acid bacteria of a species selected from the group consisting of Lactobacillus sanfranciscosi, Lactobacillus plantarum and Lactobacillus furfur.

[0147] Similar results were obtained with respect to the characteristics of the gellable biopolymer and the lactic acid bacteria solution (Tables 1 and 2) by mixing the above three lactic acid bacteria strains in the process of forming the gellable biopolymer and the lactic acid bacteria solution, and the method finally obtained microcapsules each of which contained a combination of the three strains.

[0148] Example 3 - Characterization of microcapsules containing lactic acid bacteria

[0149] The microcapsules containing lactic acid bacteria obtained according to Example 1 and Example 2 were characterized by evaluating their particle size distribution, bulk density (assessed on the uncompacted microcapsule bulk mass), tap density (assessed on the compacted microcapsule bulk mass), pH value and humidity.

[0150] The characterization results are shown in Table 4 below.

[0151] Table 4 - Characterization of microcapsules containing lactic acid bacteria

[0152]

[0153] (*) The microcapsules were dispersed by free fall using a GRADIS dry dispersion system (Sympatec) and images of the falling particles were acquired at 80 Hz using a high-resolution QICPIC camera (Sympatec).

[0154] The width of the drop shaft outlet slot was set to 40 mm. All measurements were made using the M6 ​​measurement interval (2.8 μm-5632 μm).

[0155] The images were analyzed using software and the measured values ​​of the projected area of ​​each microcapsule were extracted. For each projected area extracted, the diameter of a circle whose area is equal to the projected area was then derived (EQPC method). The diameters so obtained were used to evaluate the volume size distribution of the microcapsules.

[0156] The range of the size distribution is calculated using the following formula:

[0157] Distribution = (D90-D10) / D50

[0158] Wherein, as defined above:

[0159] D10 is the value below which 10% of the microcapsules in the size distribution have a diameter;

[0160] D50 is the value below which 50% of the microcapsules in the size distribution have a diameter;

[0161] D90 is the value below which 10% of the microcapsules in the size distribution have a diameter;

[0162] (**) Bulk density and tap density of microcapsules were determined using a TD1 tester according to USP2 method (Sotax). A certain amount of microcapsules (approximately 90 ml) was weighed into a cylinder and its volume was checked to determine the bulk density.

[0163] To determine the tap density, the cylinder was raised to 3 mm and dropped under its own weight at a frequency of 250 strokes per minute, for a total of 1250 strokes, in order to compact the microcapsules and eliminate the voids. The tap density was then calculated using the final volume evaluated after compaction.

[0164] The parameter values ​​in Table 4 show that, for a large number of microcapsules, the air-dried microcapsules are smaller and more dense than the freeze-dried microcapsules. Applicants believe that the smaller size is related to better dispersibility of the microcapsules in the dough during processing. In Applicants' opinion, the higher density is in turn related to better mechanical properties of the microcapsules (see Example 4 below), which gives the microcapsules greater storage stability.

[0165] In addition to the parameters shown in Table 4, the hygroscopicity of microcapsules containing lactic acid bacteria belonging to each of the three selected species (Lactobacillus sanfranciscosiformis (SF), Lactobacillus plantarum (PL) and Lactobacillus furfur (RO)) obtained according to Example 1 and Example 2 was also compared.

[0166] The hygroscopic behavior of the samples was quantified using dynamic vapor sorption (DVS) (SPSx-1μ High Load, ProUmid, Germany).

[0167] A progressive absorption cycle (relative humidity from 0% to 90%) was applied, with each relative humidity step increasing by 10%. The transition conditions to the next step were determined by equilibrium conditions, with a mass change of 0.01% in each step within 60 minutes or a maximum of 48 hours. The temperature was set at 25°C.

[0168] The test results of the hygroscopic behavior of the microcapsules are shown in Table 5 below.

[0169] Table 5 - Hygroscopicity test of microcapsules

[0170]

[0171]

[0172] The data clearly show that freeze-dried microcapsules have higher mass uptake than air-dried microcapsules at each relative humidity stage.

[0173] For the freeze-dried microcapsules, a strong increase in the mass uptake was observed, especially starting from a relative humidity of 70%. For the freeze-dried microcapsules, no reference point could be determined at 90% relative humidity, since the sample dissolved at such high humidity.

[0174] The air-dried microspheres showed more limited hygroscopicity compared to the freeze-dried microspheres, indicating less sensitivity to humid environments and thus greater storage stability.

[0175] Example 4 - Compression test of microcapsules containing lactic acid bacteria

[0176] The compressive strength of the microcapsules containing lactic acid bacteria belonging to each of the three selected species (Lactobacillus sanfranciscosiformis (SF), Lactobacillus plantarum (PL), and Lactobacillus furfur (RO)) obtained according to Examples 1 and 2 was measured using a texture analyzer (Perten TVT 6700 texture analyzer with a compression probe No. 670159 having a diameter of 21 mm) according to the following method.

[0177] A certain volume of microcapsules was placed in a cylindrical stainless steel container with an inner diameter of 40 mm and a height of 20 mm, so that the filling level of the microcapsules reached 15 mm.

[0178] The compression probe was located 5 mm above the highest level of the microcapsule sample.

[0179] The vertical descent speed of the probe at the start of the measurement was set to 1.7 mm / s, and the minimum force was set to 5 g. The probe stopped moving downward when it reached 40% of the initial height measured at the start of the measurement.

[0180] A force-time curve was obtained for each formulation and the maximum peak force was calculated. For each sample of microcapsules, the compressive strength was then evaluated as the peak force recorded during these transient force trends.

[0181] The results of the compressive strength measurement are shown in Table 6.

[0182] Table 6 - Compression Test

[0183]

[0184] Strength measurements show that the dried microcapsules exhibit compressive strength values ​​that are an order of magnitude higher than those of microcapsules dried by freeze drying. The inventors believe that this is in part related to the smaller size and higher density observed in the air-dried microcapsules (see Example 3 above).

[0185] Example 5 (Invention) - Production of a Processing Aid Comprising Air-Dried Microcapsules

[0186] A combination of microcapsules produced according to Example 1, which were air-dried and each contained a lactic acid bacterium belonging to a species selected from Lactobacillus sanfrancisco (SF), Lactobacillus plantarum (PL) and Lactobacillus furfur (RO), were mixed with food grade flour and xylanase in the amounts shown in Table 7 below.

[0187] Table 7 - Processing aids with microcapsules containing lactic acid bacteria

[0188]

[0189] The added xylanase was a commercial xylanase ( Novozymes), the manufacturer of which claims an activity of 235 NXU / g enzyme (NXU = new xylanase unit, a unit of measurement for enzyme activity determined internally by the manufacturer).

[0190] The food grade flour used was type "0" wheat flour, the characteristics of which are listed in Tables 8 and 9 below.

[0191] Table 8 - Chemical and physical parameters of food grade flour

[0192]

[0193] Table 9 - Rheological parameters of food grade flour

[0194]

[0195]

[0196] Example 6 (Comparative) - Preparation of a Processing Aid Including Microcapsules Dried by Freeze Drying

[0197] Microcapsules produced according to Example 1, which were air-dried and each contained lactic acid bacteria belonging to a species selected from Lactobacillus sanfrancisco (SF), Lactobacillus plantarum (PL) and Lactobacillus furfur (RO), were mixed with food-grade flour and xylanase in the amounts shown in Table 7 above.

[0198] As in previous examples, the food grade flour used was type "0" wheat flour, the characteristics of which are listed in Table 8 above.

[0199] Example 7 - Bread Preparation

[0200] Eight doughs were prepared using the direct kneading method, mixing the ingredients in a single step.

[0201] Table 10 below provides the recipes, ingredient amounts and further details for the eight doughs.

[0202] Table 10 - Dough

[0203]

[0204]

[0205] The added xylanase was a commercial xylanase ( Novozymes), the manufacturer of which claims an activity of 235 NXU / g enzyme (NXU = new xylanase unit, a unit of measurement for enzyme activity determined internally by the manufacturer).

[0206] The food grade flour used in the 8 doughs was type "0" wheat flour, the characteristics of which are listed above in Table 8. Brewer's yeast was used in all doughs.

[0207] Doughs 5 and 6 were made using the processing aids in Comparative Example 6 with and without the addition of xylanase, respectively.

[0208] Doughs 7 and 8 used the processing aid obtained according to Example 5 of the present invention with and without the addition of xylanase, respectively.

[0209] Doughs 1 and 2 (comparative) did not include lactic acid bacteria. Doughs 3 and 4 (comparative) included freeze-dried lactic acid bacteria in non-microencapsulated form.

[0210] For each dough, 80% of the water and all the remaining ingredients except salt were mixed in a spiral mixer (VMI BERTOITALIASRL 80MAG 2V model) at speed 1 for about 5 minutes and at speed 2 for about 10 minutes. When the dough became smooth, the remaining water and salt were added. The dough was then left to rest at 26°C for 45 minutes. After this step, the dough was divided into 100 g portions and fermented for 60 minutes at 28°C and 80% residual moisture.

[0211] The portions were then baked in an electric deck oven (AGIV FORNI model 306-E0) at 210°C for 18 minutes. After baking, the resulting bread was cooled to room temperature and then evaluated by visual, sensory and textural analysis. For each type of dough, 40 loaves were produced. The bread made with these recipes and this process is called "zoccoletto" and is characterized by a noticeably porous soft part and a very crisp, golden and aromatic crust.

[0212] Example 8 - Bread Height

[0213] The height of the bread was assessed using a texture analyser (Perten TVT 6700 Texture Analyser).

[0214] Each loaf was placed in the center of the texture analyzer's scale plate and the height was measured in cm at the point where the maximum volume was reached. The loaves were also weighed. The average height and weight values ​​were then calculated for the 40 loaves produced according to each recipe.

[0215] The average weight and height values ​​of the bread are shown in Table 11.

[0216] Table 11 - Average Bread Height

[0217] Dough number Average bread weight [g] Average bread height [cm] 1(Comparison) 72 4.3 2(Comparison) 78 5.9 3(Comparison) 77 5.7 4(Comparison) 78 6.2 5(Comparison) 78 5.8 6(Comparison) 80 6.0 7(Invention) 77 6.1 8(Invention) 76 6.7

[0218] The weights of the breads were very similar, except for the bread obtained from dough 1, in which no lactic acid bacteria and xylanase were used, which was lighter on average.

[0219] The average bread height increased significantly in the recipes containing added xylanase and lactic acid bacteria. The highest average height was found for bread made from dough 8, which included microcapsules containing air-dried lactic acid bacteria (produced according to Example 2) in combination with xylanase.

[0220] The height of the loaf is a relevant aspect of bread quality perception because, for the same weight, higher height and larger loaf volume are associated with better bread texture.

[0221] Example 9 - Bread Crusty Texture

[0222] The crust texture of the bread was evaluated using a texture analyzer (Perten TVT 6700 Texture Analyzer).

[0223] Place each loaf of bread on the analyzer measuring table and center it under the analyzer probe.

[0224] A compression probe with a diameter of 25 mm was used. The vertical descent speed of the probe was set at 1.7 mm / s. The probe stopped moving downward when it reached 40% of the initial height measured at the start of the measurement.

[0225] A force-time curve was obtained for each bread analyzed. From the obtained curves, the average maximum peak force was calculated for each type of bread.

[0226] The average peak force values ​​for each type of bread are shown in Table 12.

[0227] Table 12 – Bread crust texture

[0228] Dough Bread Number Peak force (average) [g] 1(Comparison) 977 2(Comparison) 2003 3(Comparison) 2194 4(Comparison) 3042 5(Comparison) 1758 6(Comparison) 2086 7(Invention) 2614 8(Invention) 3306

[0229] The bread obtained from dough 1 had a less crispy crust. The addition of xylanase (dough 2) resulted in an improvement in crispness. The addition of non-microencapsulated lactic acid bacteria (doughs 3, 5, 7) resulted in an improvement in crispness compared to bread 1, but to a lesser extent compared to the bread containing enzymes only (dough 2).

[0230] The observed effect is synergistic, since the simultaneous presence of lactic acid bacteria and xylanase significantly increases the crispiness of the crust (e.g. doughs 2, 4, 6, 8 compared to doughs 1, 3, 5, 7). The bread produced from dough 8 showed the best results in terms of the peak force required to crush the crust. This behavior is typical of a particularly crispy crust.

[0231] Example 10 - Sensory Analysis

[0232] A panel of six judges, trained to identify bread quality parameters, evaluated the bread based on colour, texture, aroma and taste.

[0233] For each type of bread, the judges rated the bread on a 9-point preference scale based on the sensory characteristics of the bread, such as crust color, crust cracks, volume increase, porosity of the soft part, aroma of freshly baked bread, toasty aroma of the crust, lactic acid smell, acidity, overall taste, sweetness, softness of the soft part during chewing, and crispness of the crust.

[0234] The results of the sensory analysis are shown in Figure 13. For each sensory parameter and each bread, the table shows the average score given by each judge. The last column shows the grand average of all scores related to all sensory parameters given by the judges for each bread.

[0235] Table 13 - Sensory analysis

[0236]

[0237] The bread obtained by adding lactic acid bacteria shows flavor characteristics in terms of characteristics known to be closely related to consumer acceptability, such as the appearance of the bread and the color of the crust.

[0238] Bread produced from dough 1, which did not include lactic acid bacteria or added enzymes, showed little increase in volume. The crust was light-colored and not very crisp. In addition, the flavor was neither rich nor aromatic.

[0239] For the dough containing xylanase only, a good increase in volume and a good improvement in crust color were evident. In breads 3, 5, 7 containing lactic acid bacteria but without added xylanase, only the increase in lactic acid aroma components was prominent.

[0240] Bread made from dough 8, which contained microcapsules of lactic acid bacteria belonging to the species Lactobacillus sanfrancisco (SF), Lactobacillus plantarum (PL) and Lactobacillus furfur (RO) and was air-dried, with the addition of xylanase, seemed to be the most attractive in terms of proofing, height and crust characteristics. The increase in volume was associated with the presence of a porous soft part with sufficient porosity, a crispy crust, amber color, and long and wide cracks on the surface. The bread was very fragrant, with a strong lactic acid aroma in both taste and aroma.

[0241] Naturally, those skilled in the art may make further modifications and variations to the above invention in order to meet specific and accidental application requirements. In any case, the variations and modifications fall within the scope of protection defined in the claims.

[0242] References

[0243] [1] et al., Composition and function of sourdough microbiota: Fromecological theory to bread quality, Int J Food Microbiol., 19; 239: 19-25, 10.1016 / j.ijfoodmicro.2016.05.004., 2016.

[0244] [2]Settanni et al., In situ activity of a bacteriocin-producing Lactococcus lactis strain. Influence on the interactions between lactic acidbacteria during sourdough fermentation, J Appl Microbiol.2005;99(3):670-81,10.1111 / j.1365-2672.2005.02647.x, 2005.

[0245] [3]Zhang et al.,Prevalence,genetic diversity and technologicalfunctions of Lactobacillus sanfranciscensis in sourdough:A review,Comprehensive Reviews in Food Science and Food Safety,18.10.1111(1541)4337.12459-2019.

[0246] [4]Ventimiglia et al,Codominance of Lactobacillus plantarum andobligate heterofermentative lactic acid bacteria during sourdoughfermentation,Food Microbiology,51,10.1016 / j.fm.2015.04.011,2015.

[0247] [5]Di Cagno et al.,Genotypic and phenotypic diversity ofLactobacillus rossiae strains isolated from sourdough,Journal of appliedmicrobiology,103,821-35,10.1111 / j.1365-2672.2007.03389.x,2007.

Claims

1. An aid for preparing dough for baked goods, comprising a food-grade carrier for baked goods and microcapsules containing live lactic acid bacteria belonging to at least one species, the microcapsules being encapsulated in a shell comprising at least one gellable biopolymer, The microcapsules are dispersed in the food-grade flour and have an average size D50 of 350 to 550 μm, preferably 390 to 490 μm, more preferably 400 to 460 μm, and a mechanical compressive strength of 3200 to 9000 g, preferably 3400 to 6000 g, more preferably 3500 to 5700 g, measured as described in this specification.

2. The auxiliary agent according to claim 1, wherein the lactic acid bacteria in the microcapsules are separated from natural sourdough type 1 yeast.

3. The auxiliary agent according to any one of the preceding claims, wherein the lactic acid bacteria contained in the microcapsule belongs to one or more species selected from the following items: Lactobacillus sanfrancisco, Lactobacillus furfur, Lactobacillus plantarum, Lactobacillus associated with digestion, Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus curvifolia, Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus freundii, Lactobacillus Hamesi fermentation agent, Lactobacillus helveticus, Lactobacillus hilaris, Lactobacillus bread, Lactobacillus associated with digestion, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus pentosaceus, Lactobacillus pontii, Lactobacillus reuteri, Lactobacillus sakei, Lactococcus lactis, Leuconostoc citrinum, Leuconostoc mesenteroides, Pediococcus pentosaceus, Weissella sinusoidalis and Weissella fusion; preferably, selected from Lactobacillus sanfrancisco, Lactobacillus furfur, Lactobacillus plantarum.

4. The adjuvant according to any one of the preceding claims, wherein the microcapsules contain a combination of lactic acid bacteria belonging to the species Lactobacillus sanfrancisco, Lactobacillus furfur and Lactobacillus plantarum.

5. The auxiliary agent according to any one of claims 1 to 3, comprising a combination of microcapsules, each microcapsule containing lactic acid bacteria belonging to a species selected from Lactobacillus sanfranciscosi, Lactobacillus furfur and Lactobacillus plantarum.

6. The auxiliary agent according to any one of the preceding claims, wherein the food-grade carrier for baked goods comprises one or more of soft wheat flour, hard wheat flour, corn flour, rice flour, spelt flour, oat flour, pea flour, chickpea flour, soy flour, rye flour, millet flour, flaxseed flour, sesame flour, sunflower seed flour, gluten, corn starch, dry sourdough, brewer's yeast, salt or a mixture thereof.

7. The adjuvant according to any one of the preceding claims, further comprising an effective amount of at least one added enzyme.

8. The auxiliary agent according to claim 7, comprising at least one added enzyme in an amount of 0.01 g / kg to 5 g / kg of the auxiliary agent.

9. The adjuvant according to any one of claims 7 or 8, wherein the at least one added enzyme is selected from xylanases, transglutaminases, cellulases, amylases, amyloglucosidases, lipases, phospholipases, asparaginases, oxidases of fungal or bacterial origin, or mixtures thereof.

10. The adjuvant according to any one of claims 7 to 9, wherein the at least one added enzyme is of the hydrolytic and non-proteolytic type.

11. The adjuvant according to any one of claims 7 to 10, wherein the at least one added enzyme comprises a xylanase capable of hydrolyzing arabinoxylan to produce xylose.

12. The auxiliary agent according to any one of the preceding claims, wherein the at least one gelling biopolymer is selected from starch or its derivatives, sodium alginate, calcium alginate, potassium alginate, ammonium alginate, gellan gum, xanthan gum, milk protein, gelatin or mixtures thereof, preferably sodium alginate.

13. The auxiliary agent according to any one of the preceding claims, obtainable by microencapsulating live lactic acid bacteria belonging to at least one species in a shell formed by a gellable biopolymer and a solution of live lactic acid bacteria, the solution comprising sodium alginate in a concentration of 2% to 15% by weight, more preferably 2% to 10% by weight, more preferably 3% to 10% by weight, even more preferably 3% to 7% by weight. 14 . The preparation according to claim 13 , wherein the sodium alginate has a viscosity of 4 to 12 mPa·s when dissolved in a 1 wt % aqueous solution at a temperature of 20° C.

15. The auxiliary agent according to any one of the preceding claims, wherein the microcapsules have a relative humidity of 10% to 17%, more preferably 11% to 16%, more preferably 12% to 15.5%.

16. The auxiliary agent according to any one of the preceding claims, wherein the microcapsules have a bulk density estimated on the uncompacted microcapsule volume mass of 0.35 to 0.55 g / mL, preferably 0.4 to 0.5 g / mL, more preferably 0.45 to 0.48 g / mL.

17. The auxiliary agent according to any one of the preceding claims, wherein the microcapsules have an average size D10 of 200 to 320 μm, more preferably 230 to 300 μm, more preferably 260 to 280 μm.

18. The auxiliary agent according to any one of the preceding claims, wherein the microcapsules have an average size D90 of 580 to 1000 μm, more preferably 600 to 850 μm, more preferably 620 to 770 μm.

19. Use of an adjuvant according to any one of the preceding claims in the preparation of dough for baked goods.

20. Use of the auxiliary agent according to claim 19 in the preparation of dough for baked goods by a direct dough preparation method.

21. A method for microencapsulating live lactic acid bacteria in a shell comprising at least one gellable biopolymer, comprising: a) providing a solution comprising a gellable biopolymer and live lactic acid bacteria belonging to at least one species; b) adding droplets of the solution of the gellable biopolymer and live lactic acid bacteria to a gelling bath comprising at least one gelling agent and causing these droplets to gel, and c) drying the gelled droplets by air drying to obtain microcapsules containing live lactic acid bacteria belonging to at least one species, said microcapsules having an average size D50 of 350 to 550 μm, preferably 390 to 490 μm, more preferably 400 to 460 μm, and having a mechanical compressive strength measured as described in the present specification of 3200 to 9000 g, preferably 3400 to 6000 g, more preferably 3500 to 5700 g.

22. A microencapsulation process according to claim 21, wherein said step c) of drying the gelled droplets comprises subjecting the gelled droplets to a stream of air at a temperature of 25°C to 35°C, preferably about 30°C, until said microcapsules reach a relative humidity of 10% to 17%, more preferably 11% to 16%, more preferably 12% to 15.5%.

23. The microencapsulation method according to claim 21 or 22, wherein the at least one gelable biopolymer comprises sodium alginate having a viscosity of 4 to 12 mPa·s when dissolved in a 1 wt % aqueous solution at 20°C, wherein the concentration of sodium alginate in the solution of the gelable biopolymer and live lactic acid bacteria is 2 to 15 wt %, more preferably 2 to 10 wt %, more preferably 3 to 10 wt %, even more preferably 3 to 7 wt %.

24. A method for producing an auxiliary agent for preparing baked goods, comprising: x) providing microcapsules containing live lactic acid bacteria belonging to at least one species encapsulated in a shell comprising at least one gellable biopolymer by a microencapsulation process according to any one of claims 21 to 23, said microcapsules having an average size of 350 to 550 μm, preferably 390 to 490 μm, more preferably 400 to 460 μm, and having a mechanical compressive strength of 3200 to 9000 g, preferably 3400 to 6000 g, more preferably 3500 to 5700 g measured as described in the present specification; and y) dispersing the microcapsules in a certain amount of a food grade carrier for baked food.

25. A dough for baked food, comprising the auxiliary agent according to any one of claims 1 to 18, water and optionally other raw materials.

26. A method for preparing a baked product, comprising: - forming a slurry by mixing the auxiliary agent according to any one of claims 1 to 18 with water and optionally other raw materials, -Optionally, divide the dough into several portions; - optionally, giving the dough or dough portion a desired shape; and - Bake the dough or dough portions in an oven.

27. The preparation method according to claim 26, which is a direct dough making method.

28. The baked food obtained by the preparation method according to claim 26 or 27.

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