Fermented onion composition

Abstract

To provide a composition that can be advantageously used as an effective and label-friendly food ingredient for improving the overall quality of food.SOLUTION: A fermented onion composition has a dry matter content of at least 8 wt.%, and comprises, per gram of dry matter: a) 0-150 mg of sugars selected from fructose, glucose, sucrose, and combinations thereof; and b) 75-500 mg acid equivalent of organic acids selected from propionic acid, lactic acid, acetic acid, and combinations thereof, or 200-800 mg lactic acid equivalent. When the composition is diluted with distilled water such that the dry matter content becomes 5 wt.%, at least 90 wt.% of the dry matter contained in the composition is soluble at 20°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] [Technical field of the invention] The present invention relates to a fermented onion composition having a dry matter content of at least 8% by weight, which comprises, per gram dry matter: a) Fructose, glucose, sucrose and combinations thereof 0 to 150 mg of sugars selected from the group consisting of: b) 5 to 250 mg of phenols selected from an acid equivalent of gallic acid, an acid equivalent of ferulic acid, quercetin, kaempferol, and combinations thereof; c) 75 to 500 mg acid equivalent of an organic acid selected from propionic acid, lactic acid, acetic acid, and combinations thereof. The present invention relates to a fermented onion composition comprising:

[0002] The fermented onion composition of the present invention can be advantageously used as an effective, label-friendly food ingredient to improve the overall quality of food products.

[0003] The present invention provides a method for preparing a fermented onion composition, comprising the steps of: providing an onion base material containing 8 to 50% by weight of dry matter and 50 to 90% by weight of water, wherein at least 40% by weight of the dry matter is derived from onion; inoculating the substrate with a microorganism selected from lactic acid bacteria, Propionibacterium species, and combinations thereof; incubating the inoculated substrate at a temperature in the range of 25-60°C for at least 12 hours to produce an onion fermentation; The present invention further provides a method comprising:

[0004] [Background of the invention] Food preservation involves measures taken to maintain food in its desired characteristics or natural state for as long as possible. Mechanical, physical, chemical, and microbiological influences are the primary causes of food deterioration and spoilage. Based on the type of measures, the major food preservation methods can be classified as follows: (1) slowing or inhibiting chemical deterioration and microbial growth; (2) directly inactivating bacteria, yeast, koji, or enzymes; and (3) preventing reinfection before and after processing.

[0005] The use of chemicals in food is a well-known method of food preservation. A wide variety of chemicals are used in food preservatives as additives to control pH and provide food functionality and preservatives, such as antimicrobials and antioxidants. Many legally approved food preservatives are organic acids and esters, including sulfites, nitrites, acetic acid, citric acid, lactic acid, sorbic acid, benzoic acid, sodium diacetate, sodium benzoate, methylparaben, ethylparaben, propylparaben, and sodium propionate. Some of these additives may be perceived as undesirable or less appealing to consumers, for example, because they are perceived as "chemical," "artificial," or "unhealthy." Consumers would prefer bio-derived or renewable additives that are natural and can be labeled as food products rather than additives. Food companies are making progress in developing products to meet these consumer demands, utilizing, for example, vegetables, fruits, herbs, and spices, or products fermented with bacteria, yeast, and koji, to preserve food.

[0006] Many preservative products are based, at least in part, on organic acids such as acetic acid, lactic acid, and propionic acid. When a weak acid dissolves in water, an equilibrium is established between undissociated acid molecules and charged anions, and the pH decreases as the proportion of undissociated acid increases. The currently accepted antimicrobial strategy proposes inhibition by lowering the pH of the interior of the cell. Undissociated acid molecules are lipophilic and readily penetrate the plasma membrane by diffusion. In the cytoplasm, where the pH is approximately 7.0, acid molecules dissociate into charged anions and protons. These are unable to traverse the lipid bilayer and accumulate in the cytoplasm, thus lowering the pH and inhibiting metabolism. The properties of organic acids as microbial inhibitors in foods have some limitations. They are often ineffective when initial levels of microorganisms are high. Many microorganisms use organic acids as a metabolizable carbon source. There is inherent variation in resistance among individual strains.

[0007] WO 2018 / 106109 describes a natural antimicrobial composition comprising a combination of a buffered food acid component and a nitrite source in the form of a cultured vegetable extract.

[0008] Santas et al. (Onion. A natural alternative to artificial food preservatives, AgroFood industry hi-tech-September / October (2010) - vol 21 n 5) state that onions are widely used as a food ingredient and are known to be a good source of bioactive compounds, such as sulfur-containing compounds and flavonoids, which are well known for their beneficial health effects, antioxidant and antimicrobial properties. The authors report that several studies have tested the effects of organosulfur compounds in in vitro experiments and have shown that they exert significant inhibition against Gram-positive bacteria of the genera Bacillus, Micrococcus, Staphylococcus, and Streptococcus, as well as Gram-negative bacteria such as Salmonella enteridis or some strains of Escherichia coli. Additionally, the antiyeast and antifungal activities of onions are primarily due to the presence of organosulfur compounds that inhibit the growth of yeast and fungi. The authors further explain that the flavonols quercetin and kaempferol, which are typically present in significant amounts in onions, are the primary nonvolatile compounds responsible for their antimicrobial properties. In vitro studies have shown that onion flavonoids can effectively inhibit the growth of gram-positive bacteria that cause food spoilage, such as Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus, and Listeria monocytogenes.

[0009] Dublado et al. (FERMENTED ONION (Allium cepa) JUICE SUPPLEMENTATION TO BROILERS, Journal of Science, Engineering and Technology (2013), 71-77) described a study investigating the effect of fermented onion juice on the growth performance of young chickens. Fermented onion juice was prepared by mixing 1 kg of chopped onion bulbs with 0.5 kg of brown sugar in a bucket, covering the bucket with a plastic bag, and placing a weight on top. After 12 hours, the weight was removed and the bucket was covered with manila paper and secured to the bucket with a rubber band. On the seventh day, the juice was collected in bottles and stored in a cool place.

[0010] [Summary of the Invention] The present inventors have discovered that, despite their inherent antimicrobial activity, the functional properties of onion juice or onion pulp can be further improved as a food ingredient by fermenting it with Propionibacterium or lactic acid bacteria. Onions have a high content of fermentable sugars which can be metabolized to propionic acid (and acetic acid) by Propionibacterium or to lactic acid by lactic acid bacteria. The fermented onion products so obtained have antimicrobial activity due to the presence of antimicrobial phenolics naturally present in onions and the presence of propionic acid, lactic acid and / or acetic acid produced during fermentation. Furthermore, the fermented onion products have antioxidant activity and can improve the textural, organoleptic and other functional properties of food products.

[0011] The present invention therefore provides a fermented onion composition having a dry matter content of at least 8% by weight, wherein per gram dry matter: a) 0 to 150 mg of a sugar selected from fructose, glucose, sucrose, and combinations thereof; b) 5 to 250 mg of phenols selected from an acid equivalent of gallic acid, an acid equivalent of ferulic acid, quercetin, kaempferol, and combinations thereof; c) 75 to 500 mg acid equivalent of an organic acid selected from propionic acid, lactic acid, acetic acid, and combinations thereof. The present invention provides a fermented onion composition comprising:

[0012] The sugars content of the fermented onion composition is substantially lower than the sugar content of onions due to fermentative conversion of these sugars to organic acids. The concentration levels of organic acids in the fermented onion composition are much higher than those found naturally in onions or onion juice.

[0013] The fermented onion composition of the present invention can be advantageously used as an effective, label-friendly food ingredient to improve the overall quality of food products.

[0014] The present invention provides a method for preparing a fermented onion composition, comprising the steps of: providing an onion base material containing 10 to 50% by weight of dry matter and 50 to 90% by weight of water, wherein at least 40% by weight of the dry matter is derived from onion; inoculating the substrate with a microorganism selected from lactic acid bacteria, Propionibacterium sp., and combinations thereof; incubating the inoculated substrate at a temperature in the range of 25-60°C for at least 12 hours to produce an onion fermentation; Also provided is a method comprising:

[0015] [Detailed description of the invention] A first aspect of the invention is a fermented onion composition having a dry matter content of at least 8% by weight, wherein per gram dry matter: a) 0 to 150 mg of a sugar selected from fructose, glucose, sucrose, and combinations thereof; b) 5 to 250 mg of phenols selected from an acid equivalent of gallic acid, an acid equivalent of ferulic acid, quercetin, kaempferol, and combinations thereof; c) 75 to 500 mg acid equivalent of an organic acid selected from propionic acid, lactic acid, acetic acid, and combinations thereof. The present invention relates to a fermented onion composition comprising:

[0016] The term "acid" as used in this disclosure includes the protonated form of the acid, the dissociated form of the acid, and acid salts, unless otherwise indicated. Thus, the term "citric acid" includes, for example, CHO(COOH), CHO(COOH)(COO). - , C3H5O(COO) 3- 3. C3H5O(COONa)3 and C3H5O(COOH)(COONa)(COO) - Includes.

[0017] As used in this disclosure, the term "mg acid equivalent" means the total amount of a particular acid when the acid exists only in its fully protonated form. Thus, 200 mg of sodium propionate corresponds to 200 x 74.08 / 96.06 = 154.24 mg acid equivalent.

[0018] As used in this disclosure, the term "quercetin" encompasses both the aglycone as well as the glycosides of quercetin, unless otherwise indicated.

[0019] The fermented onion composition of the invention may be provided in the form of a liquid, a paste or a solid (for example, powder). Usually, the water content of the fermented onion composition is 0 to 50% by weight, more preferably 0 to 40% by weight, more preferably 0 to 35% by weight, most preferably 0 to 18% by weight.

[0020] According to a particularly preferred embodiment, the fermented onion composition is a granular composition, preferably one having a mean diameter D[4,3] in the range of 100 to 900 μm, more preferably 200 to 800 μm, most preferably 300 to 700 μm. Here, the "mean diameter D[4,3]" means the De Brouckere mean diameter or volume mean diameter, which can be defined as the volume-weighted mean assuming that spherical particles of the same volume are the actual particles. This mean diameter is calculated by the following equation: D[4,3]=(Σn i D i4 ) / (Σn i D i 3 ) During the ceremony, D i = average particle size in particle size category i, n i = number of particles in size category i is.

[0021] In a further preferred embodiment, at least 80% by weight of the granular composition has a particle size in the range of 40 to 1500 μm, more preferably in the range of 100 to 1200 μm, and most preferably in the range of 200 to 1000 μm. Mass-weighted mean particle size can be suitably measured using laser diffraction (Malvern Mastersizer 3000).

[0022] The combination of components a) to c) (sugars, phenols, and organic acids) typically constitutes at least 40% by weight of the dry matter contained in the composition. More preferably, the combination of components a) to c) constitutes 45 to 94% by weight of the dry matter contained in the composition. Most preferably, the combination of components a) to c) constitutes 50 to 89% by weight of the dry matter contained in the composition.

[0023] The fermented onion composition usually contains 0 to 120 mg, more preferably 0 to 100 mg, most preferably 0 to 90 mg of sugars selected from fructose, glucose, sucrose and combinations thereof per gram of dry matter.

[0024] According to a particularly preferred embodiment, the fermented onion composition further comprises component d) in the form of an onion acid selected from citric acid, malic acid, tartaric acid, oxalic acid, pyruvic acid, succinic acid and combinations thereof. The concentration levels of the onion acids in the fermented onion composition are comparable to those naturally found in onions and onion juice. Per gram dry matter, the onion acids are preferably present in the fermented onion composition in a concentration of 3 to 120 mg acid equivalents, more preferably 5 to 110 mg acid equivalents, even more preferably 10 to 100 mg acid equivalents and most preferably 15 to 90 mg acid equivalents.

[0025] The combination of components a) to d) (sugars, phenols, organic acids and onion acids) typically constitutes at least 50% by weight of the dry matter contained in the composition. More preferably, the combination of components a) to d) constitutes 52-95% by weight of the dry matter contained in the composition. Most preferably, the combination of components a) to d) constitutes 55-90% by weight of the dry matter contained in the composition.

[0026] In one embodiment of the present invention, the composition contains 200-800 mg lactic acid equivalents per gram of dry matter. More preferably, the composition contains 300-700 mg lactic acid equivalents per gram of dry matter. Most preferably, the composition contains 400-600 mg lactic acid equivalents per gram of dry matter.

[0027] In another embodiment of the present invention, the composition contains 75 to 450 mg of propionic acid equivalents per gram of dry matter. More preferably, the composition contains 125 to 400 mg of propionic acid equivalents per gram of dry matter. Most preferably, the composition contains 175 to 350 mg of propionic acid equivalents per gram of dry matter.

[0028] In addition to propionic acid, the composition typically contains 10-150 mg acetic acid equivalents per gram of dry matter, more preferably 20-130 mg acetic acid equivalents, most preferably 30-110 mg acetic acid equivalents.

[0029] The antimicrobial activity of the fermented onion composition can be further enhanced by utilizing fermentation to produce not only organic acids but also bacteriocins. The bacteriocins may be one or more bacteriocins selected from the group consisting of nisin, subtilin, cytolysin, variacin, sakacin, pediocin, curvaticin, enterocin, and lactacin. More preferably, the bacteriocin may be one or more selected from the group consisting of nisin, sakacin, pediocin, and lactacin. Most preferably, the bacteriocin is nisin. According to a preferred embodiment, the composition contains 5,000 to 500,000 IU of nisin equivalent activity per gram of dry matter. More preferably, the composition contains 10,000 to 400,000 IU of nisin equivalent activity per gram of dry matter. Most preferably, the composition contains 50,000 to 300,000 IU of nisin equivalent activity per gram of dry matter.

[0030] Since both lactic acid and bacteriocin can be produced by lactic acid bacteria, in a preferred embodiment the fermented onion composition contains both lactic acid and bacteriocin. In an even more preferred embodiment the fermented onion composition contains lactic acid and nisin.

[0031] The fermented onion composition usually has a total nitrogen content of 1.5 to 35 mg per gram dry matter, more preferably a total protein content of 2 to 30 mg per gram dry matter, and most preferably a total protein content of 3 to 25 mg per gram dry matter. The total protein content is suitably determined using the Kjeldahl method.

[0032] Preferably, at least 90% by weight, more preferably at least 95% by weight of the protein contained in the fermented onion composition is onion protein.

[0033] According to a further preferred embodiment, at least 60% by weight of the dry matter contained in the fermented onion composition comes from onions, more preferably at least 70% by weight, and most preferably at least 80% by weight.

[0034] The fermented onion compositions of this invention will typically contain substantial amounts of components naturally occurring in onions such as onion acids, phenols (including flavonols), sulfur-containing compounds, aldehydes, ketones and the like.

[0035] The fermented onion composition preferably contains 0.05 to 30 mg acid equivalent of citric acid per gram of dry matter, more preferably 0.15 to 25 mg acid equivalent of citric acid, most preferably 0.25 to 20 mg acid equivalent of citric acid.

[0036] The fermented onion composition preferably contains 0.2 to 30 mg acid equivalent of malic acid, more preferably 0.5 to 25 mg acid equivalent of malic acid, and most preferably 1 to 20 mg acid equivalent of malic acid, per gram of dry matter.

[0037] The fermented onion composition preferably contains 1 to 150 mg acid equivalent of gallic acid per gram dry matter, more preferably 3 to 125 mg acid equivalent of gallic acid, most preferably 5 to 100 mg acid equivalent of gallic acid.

[0038] The fermented onion composition preferably contains 0.05 to 8 mg acid equivalent of ferulic acid per gram dry matter, more preferably 0.15 to 7 mg acid equivalent of ferulic acid, most preferably 0.25 to 6 mg acid equivalent of ferulic acid.

[0039] The fermented onion composition preferably contains 0.2 to 30 mg of quercetin per gram of dry matter. More preferably, the fermented onion composition contains 0.5 to 25 mg of quercetin per gram of dry matter. Most preferably, the fermented onion composition contains 1 to 20 mg of quercetin per gram of dry matter. The amount of quercetin herein means quercetin in the form of aglycone.

[0040] Preferably, the fermented onion composition contains 0.05 to 8 mg of kaempferol per gram dry matter, more preferably 0.15 to 7 mg of kaempferol per gram dry matter, and most preferably 0.25 to 6 mg of kaempferol per gram dry matter.

[0041] Cellular material from the microorganisms used in the preparation of the fermented onion composition will usually be present in said composition. Thus, in a preferred embodiment, said composition contains cellular material from Lactic Acid Bacteria and / or Propionibacterium sp.

[0042] According to another preferred embodiment, the majority of the dry matter contained in the fermented onion composition is water-soluble. Preferably, when the composition is diluted with distilled water to a dry matter content of 5% by weight, at least 80% by weight, more preferably at least 90% by weight, most preferably at least 95% by weight of the dry matter contained in the composition dissolves at a temperature of 20° C.

[0043] The fermented onion composition of the invention is preferably obtained by the following preparation method, and even more preferably by the following preparation method.

[0044] Another aspect of the present invention is a process for preparing a fermented onion composition comprising the steps of: providing an onion base material containing 10 to 50% by weight of dry matter and 50 to 90% by weight of water, wherein at least 40% by weight of the dry matter is derived from onion; inoculating the substrate with a microorganism selected from lactic acid bacteria, Propionibacterium sp., and combinations thereof; incubating the inoculated substrate at a temperature in the range of 25-60°C for at least 12 hours to produce an onion fermentation; The present invention relates to a method, comprising:

[0045] According to a particularly preferred embodiment, the aforementioned preparation process results in a fermented onion composition as defined above in this disclosure.

[0046] The onion base material used in the above preparation method preferably comprises onion juice, onion pulp or a combination thereof. The onion juice may be obtained in the form of concentrated onion juice such as onion juice powder. The onion pulp may suitably be obtained in the form of onion powder. The powder or concentrate may be diluted with water to obtain an onion base material having 10-50% dry matter as starting material for fermentation.

[0047] In a preferred embodiment at least 50% by weight of the dry matter of the onion base material is derived from onion, more preferably at least 70% by weight, most preferably at least 80% by weight.

[0048] Preferably, at least 80% by weight of the dry matter of the onion base material is provided from onion juice and / or onion pulp, more preferably at least 80% by weight of the dry matter of the onion base material is provided from onion juice, most preferably from concentrated onion juice having a water content of less than 40% by weight.

[0049] The onion base material typically contains at least 40% by weight, more preferably at least 50% by weight, and most preferably at least 55% by weight, of sugars selected from fructose, glucose, sucrose and combinations thereof, calculated by weight of dry matter.

[0050] In an advantageous embodiment of the invention, the onion substrate has been treated with invertase before inoculation, which converts sucrose into glucose and fructose which are more efficiently metabolized by certain strains of Lactobacillus and / or Propionibacterium.

[0051] The total nitrogen content of the onion base material is preferably in the range of 0.15 to 3.5% by weight, more preferably 0.2 to 3.0% by weight, and most preferably 0.3 to 2.5% by weight, calculated on a dry basis. The total protein content of the onion base material is suitably measured using the Kjeldahl method.

[0052] The onion acids selected from citric acid, malic acid, gallic acid and combinations thereof are preferably present in the onion base material at a concentration of 3 to 120 mg acid equivalents per gram dry matter, more preferably 5 to 110 mg acid equivalents, even more preferably 10 to 100 mg acid equivalents, and most preferably 15 to 90 mg acid equivalents per gram dry matter.

[0053] The onion base material preferably contains 0.02 to 3% by weight of quercetin, more preferably 0.05 to 2.5% by weight, and most preferably 0.1 to 2% by weight of quercetin, calculated on a dry basis. The amount of quercetin herein means quercetin in the form of aglycone.

[0054] The onion base material preferably contains 11 to 45% by weight of dry matter and 89 to 55% by weight of water, more preferably 12 to 40% by weight of dry matter and 88 to 60% by weight of water.

[0055] The onion substrate is preferably pasteurised or sterilised prior to inoculation. Most preferably the onion substrate is sterile when inoculated with lactic acid bacteria and / or Propionibacterium.

[0056] Usually the onion base is inoculated with at least 0.1% w / w of a microbial preculture, more preferably with 0.5 to 40% w / w of the microbial preculture, most preferably with 1.0 to 30% w / w of the microbial preculture.

[0057] The inoculated substrate is incubated at a temperature preferably in the range of 20 to 70°C, more preferably 25 to 65°C, for at least 12 hours to produce an onion fermentation product.

[0058] According to another preferred embodiment, the inoculated substrate is incubated under anaerobic conditions.

[0059] Typically, incubation is continued until the incubated substrate contains 10 to 50% by weight of an organic acid selected from propionic acid, lactic acid, and combinations thereof, calculated on a dry basis.

[0060] In one embodiment of the present invention, a base is added during and / or after the incubation so as to neutralize at least a part of the organic acid formed during the incubation. Preferably, a base sufficient to raise the pH of the onion fermented product to 5.0 or higher, more preferably to raise the pH of the onion fermented product to 5.5 to 7.5, is added.

[0061] After incubation, the onion ferment is preferably pasteurized, for example by UHT pasteurization.

[0062] After incubation, the onion fermentate is preferably concentrated to a dry matter content of at least 50% by weight, more preferably at least 60% by weight.

[0063] According to a particularly preferred embodiment, the onion fermentate is dried to produce a dry powder having a moisture content of not more than 18% by weight, preferably not more than 15% by weight. Suitable drying methods are spray drying, drum drying and freeze drying. After drying, the dried onion fermentate may suitably undergo further processing steps such as milling, sieving, granulation, etc. Most preferably, the onion fermentate is dried by spray drying.

[0064] A further aspect of the invention relates to methods for preparing a food product or a beverage comprising the step of combining the fermented onion composition according to the invention with one or more other ingredients. The fermented onion composition of the invention is particularly suitable for preserving food products such as meat products, savory products such as soups and sauces, salads and (vegetable) beverages.

[0065] Preferably, the method for preparing a food product or beverage comprises the step of incorporating the fermented onion composition at a concentration of 0.1 to 10% by weight of the final food product or beverage, more preferably at a concentration of 0.2 to 5% by weight.

[0066] Yet another aspect of the present invention relates to the use of the fermented onion composition of the present invention as a food preservative. This use typically involves mixing the fermented onion composition with one or more other ingredients of the product to be preserved.

[0067] Yet another aspect of the present invention relates to the use of a fermented onion composition for preventing microbial spoilage of food products. Yet another aspect of the present invention relates to the use of a fermented onion composition for improving the organoleptic properties of meat products.

[0068] The present invention is further illustrated by the following non-limiting examples.

[0069] [Example] Example 1 The fermented onion composition according to the invention was produced by treating onion juice with invertase to convert sucrose to glucose and fructose, followed by fermentation using B. coagulans (deposited at the DSMZ (German collection of microorganisms and cell cultures) by Corbion NV on March 20, 2020, accession number DSM 33469) to convert the fermentable sugars present in the treated onion juice into lactic acid. The results shown below were obtained from six repetitions of the experiment.

[0070] Details of the onion juice concentrate are given in Table 1.

[0071] [Table 1]

[0072] 3300 grams of onion juice concentrate was diluted with 6700 grams of demineralized water to prepare an onion juice stock solution. The diluted onion juice was then subjected to UHT sterilization. The sterilized onion juice dilution was cooled to ambient temperature and then used to prepare an onion juice medium. For this, 2500 grams of onion juice stock solution was mixed with 2245 grams of demineralized water. The pH of the resulting medium was about 4.6. Then, after all the sucrose had been converted to glucose and fructose, 5 ml of invertase solution was added and incubated at 54°C for 30 minutes.

[0073] The sugar composition of a typical onion juice medium after invertase treatment is shown in Table 2.

[0074] [Table 2]

[0075] The pH of the invertase-treated onion juice medium was then adjusted to 6.4 by adding a 40% caustic solution of Ca(OH)2 and NaOH (50 / 50 w / w ratio), followed by incubation with B. coagulans (OD 500 6-7) was inoculated into 250 ml of inoculum.

[0076] Fermentation was carried out in a stirred tank fermentor under anaerobic conditions at 54°C. The temperature of the fermentation broth was maintained within the range of 50-56°C during fermentation. The caustic solution described above was used to maintain the pH within the range of 6-6.8.

[0077] After 30 hours of fermentation, samples were taken from the fermentation broth and analyzed, the results of which are shown in Table 3.

[0078] [Table 3]

[0079] Example 2 The fermented onion composition according to the invention was produced by treating onion juice with invertase to convert sucrose into glucose and fructose, followed by fermentation using P. acidipropionici (deposited with the DSMZ (German collection of microorganisms and cell cultures) by Corbion NV on March 20, 2020, accession number DSM 33468) to convert the fermentable sugars present in the treated onion juice into propionic acid and acetic acid. The results shown below were obtained by repeating the experiment seven times.

[0080] 3300 grams of the same onion juice as in Example 1 was diluted with 6700 grams of demineralised water. The diluted onion juice was then subjected to UHT sterilisation.

[0081] After the pasteurized onion juice dilution had cooled to ambient temperature, an onion juice fermentation medium was prepared and the invertase solution was added. The composition of the fermentation medium is shown in Table 4.

[0082] [Table 4]

[0083] The pH of the onion juice medium was about 4.6. After 2 hours of incubation at 35°C, all of the sucrose was converted to glucose and fructose.

[0084] Next, the pH of the dilution of invertase-treated onion juice was adjusted to 7 by adding a 40% caustic solution of Ca(OH)2 and NaOH (50 / 50 w / w ratio), followed by the addition of P. acidipropionici (OD 500 30-40) was inoculated into 250 ml of inoculum.

[0085] Fermentation was carried out in a stirred tank under anaerobic conditions. The temperature of the fermentation broth was maintained between 30 and 38°C, and caustic solution (20% Ca(OH)2) was added to maintain the pH in the range of 6 to 6.8.

[0086] After 40 hours of fermentation, samples were removed from the fermentation broth and analyzed. The results of the analysis of a representative fermentation in onion juice medium are shown in Table 5.

[0087] [Table 5]

[0088] Example 3 The effect of using a fermented onion composition on purge loss in turkey meat formulations, pH and color of cooked meat was investigated. Lab-scale tests were conducted using 13 mm turkey breast fillets with a 20% w / w brine solution.

[0089] Five different brine solutions containing salt, cane sugar and carrageenan were used. Four of the brine solutions tested additionally contained the fermented onion composition of Example 1 or Verdad powder N20 (sold by Corbion, The Netherlands). The concentrations of salt, cane sugar and carrageenan, calculated from the weight of the final meat product, were 1.6%, 0.5% and 0.4%, respectively. The concentrations of the fermented onion composition and Verdad powder, also calculated from the weight of the final meat product, are shown in Table 6. The final concentration of lactic acid was similar for Onion 1 and N20-1 (low dosage) and Onion 2 and N20-2 (high dosage).

[0090] [Table 6]

[0091] The brine solution was prepared by adding the brine ingredients to water followed by mixing for 5 minutes. The brine solution was then added to the meat pieces and vacuum tumbled for 2 hours. After tumble tumbling, the meat batter was vacuum packed into 60 mm plastic high-barrier containers and thermally processed to an internal temperature of 72°C according to the cooking schedule presented in Table 7. The resulting meat product was allowed to cool overnight to an internal temperature of 2°C.

[0092] [Table 7]

[0093] The pH of the raw meat, brine, meat batter, and cooked meat products was measured. Purge loss and color were also measured for each meat product. Purge loss is equal to the weight difference between the pre-cooked and cooked turkey meat product (without free liquid) divided by the weight of the meat product before cooking. Color was measured according to CIELAB standards. The results are presented in Table 8 and show that fermented onion performed better than Verdad powder N20.

[0094] [Table 8]

[0095] Example 4 The antimicrobial effect of the fermented onion composition was investigated on cooked chicken rolls inoculated with a mixture of lactic acid bacteria (LAB) that are associated with meat spoilage.

[0096] The growth of lactic acid bacteria in meat samples spiked with onion ferment (test product) was followed during storage compared to samples spiked with a commercial preservative product (reference product) and samples without added preservative (control).

[0097] Meat sample preparation Chicken roll samples (Table 9) were prepared using 30mm chicken tenderloins and injected with 18% brine. The meat samples were mixed with all ingredients and then rolled for 1 hour. A series of cooks were performed until the center of the roll reached 72°C.

[0098] [Table 9]

[0099] Cooked meat samples were inoculated with a mixture of six LAB strains to reach a bacterial concentration of 3 LogCFU / g. The LAB mixture contains lactic acid bacteria obtained from spoiled meat and is known to be relatively tolerant to organic acids. Cooked meat samples were kept at 7°C. LAB growth was followed over time by harvesting and growing bacterial cells from approximately 20g samples. Duplicate samples were used for each time point.

[0100] result The pH and water activity (Aw) of the different samples are shown in Table 10.

[0101] [Table 10]

[0102] The water activity of the reference and test product samples was very similar, while the water activity of the control was slightly higher. The addition of both the reference and test products resulted in a decrease in pH, although the test product sample was almost 0.2 units higher. This may be due to the higher buffering capacity of the test product.

[0103] The results of bacterial growth measurements are shown in Table 11.

[0104] [Table 11]

[0105] Both the Verdad Opt. Powder N70 and the test product containing onion ferment inhibited the growth of resistant LAB in the chicken rolls compared to the control. The test products performed slightly better despite the higher pH of the chicken rolls.

Claims

1. 1. A fermented onion composition having a dry matter content of at least 8% by weight, comprising per gram dry matter: a) 0-150 mg of a sugar selected from fructose, glucose, sucrose, and combinations thereof; b) 5 to 250 mg of phenols selected from acid equivalents of gallic acid, acid equivalents of ferulic acid, quercetin, kaempferol, and combinations thereof; c) 75 to 500 mg acid equivalent of an organic acid selected from propionic acid, lactic acid, acetic acid, and combinations thereof.

1. A fermented onion composition comprising:

2. The fermented onion composition according to claim 1, which has a water content of 0 to 50% by weight.

3. 3. The fermented onion composition according to claim 1 or 2, further comprising 3 to 120 mg acid equivalent of component d) in the form of an onion acid selected from citric acid, malic acid, tartaric acid, oxalic acid, pyruvic acid, succinic acid and combinations thereof.

4. 4. The fermented onion composition according to claim 3, wherein the combination of components a) to d) constitutes at least 50% by weight of the dry matter contained in the composition.

5. The fermented onion composition according to any one of claims 1 to 4, which contains 200 to 800 mg of lactic acid equivalent per gram dry matter.

6. The fermented onion composition according to any one of claims 1 to 5, which contains 75 to 450 mg of propionic acid equivalent per gram dry matter.

7. 7. The fermented onion composition according to any one of claims 1 to 6, having a total nitrogen content of 1.5 to 35 mg per gram dry matter.

8. The fermented onion composition according to any one of claims 1 to 7, which contains 0.2 to 30 mg of quercetin per gram dry matter.

9. Per gram of dry matter, 0.05 to 30 mg acid equivalents of citric acid, 0.2 to 30 mg acid equivalents of malic acid, 1 to 150 mg acid equivalent of gallic acid The fermented onion composition according to any one of claims 1 to 8, comprising:

10. The fermented onion composition according to any one of claims 1 to 9, which contains cellular material from lactic acid bacteria and / or Propionibacterium sp.

11. 1. A method for preparing a fermented onion composition comprising the steps of: providing an onion base material containing 10-50% by weight of dry matter and 50-90% by weight of water, wherein at least 40% by weight of said dry matter is from onion; inoculating the substrate with a microorganism selected from lactic acid bacteria, Propionibacterium sp., and combinations thereof; incubating the inoculated substrate at a temperature in the range of 25-60°C for at least 12 hours to produce an onion fermentation; A method comprising:

12. 12. The method of claim 11 , wherein the dry matter of the onion base material is provided from onion juice and / or onion pulp.

13. 13. A method according to claim 11 or 12, for producing the fermented onion composition according to any one of claims 1 to 10.

14. 11. A method for preparing a food product or a beverage, comprising the step of combining the fermented onion composition according to any one of claims 1 to 10 with one or more other ingredients.

15. Use of the fermented onion composition according to any one of claims 1 to 10 as a food preservative.

Images