Method of increasing avenanthramide content in oats

Abstract

The present disclosure relates to a method of increasing avenanthramide content in oats through dehulling and subsequent bioactivation of the dehulled oats. The present disclosure also relates to oat material obtainable by said method and to consumables comprising said oat material.

Description

METHOD OF INCREASING AVENANTHRAMIDE CONTENT IN OATSFIELD OF INVENTION

[0001] The present disclosure relates to a method of increasing avenanthramide content in oats through dehulling and subsequent bioactivation of the dehulled oats. The present disclosure also relates to oat material obtainable by said method and to consumables comprising said oat material.BACKGROUND

[0002] Avenanthramides are a class of polyphenolic alkaloids uniquely present in oats (Avena sativa). The chemical structure of avenanthramides is comprised of either an hydroxycinnamic acid and an anthranilic acid (type I, later abbreviated as AVN) or an avenalumin acid and an anthranilic acid (type II, later abbreviated as AVL). The nomenclature of avenanthramides may follow both the Dimberg or the Collins system. The three most common ones found in oats are the avenanthramide 2p or avenanthramide A (p-coumaroylated anthranilic acid), avenanthramide 2f or avenanthramide B (feruloylated anthranilic acid) and avenanthramide 2c or avenanthramide C (caffeoylated anthranilic acid) according to the Dimberg and the Collins nomenclature systems, respectively. The total number of discovered and identified avenanthramides reach well over forty today.

[0003] Interestingly, an emerging body of scientific literature gives evidence that avenanthramides have beneficial health effects, including anti-oxidative, anti-inflammatory, anti-diabetic and anti-cancer properties. Regardless of their great potential, the utilization of postprandial benefits and bioactivity is restricted by their low amount in unprocessed oats (approx. 30 mg / kg), even though avenanthramides withstand food processing and are therefore present also in the end products. Thus there is a need to enrich these compounds into commercial oat products and followingly, to everyday nutrition and lifestyle.

[0004] There are several possible ways to enrich avenanthramides into oats and oat products. Firstly, plant breeding both by traditional and gene modification methods may lead to elevated avenanthramide contents yet these methods are slow and gene modification is poorly accepted. Secondly, food-grade chemical extraction and down-stream purification is plausible yet unlikely to be commercially viable. Thirdly, using a chemical elicitor treatment before harvest induces the biosynthesis of avenanthramides but is not accepted within the EU. Lastly, a time-taking malting process of oats for approx. 5 days enhances the biosynthesis of avenanthramides, representing challenges regarding production efficiency and additional production costs and food safety due to the possible increase in the production ofFusariumtoxins such as deoxynivalenol during the prolonged malting process. The above-mentioned currently available methods leave a great need for a fast, efficient and cost-effective method to increase the amount of avenanthramides in oats and oat products.

[0005] EP2411527 discloses a method for increasing the levels of avenanthramides in hulless (naked) oats through a false malting procedure, wherein a secondary dormancy is introduced to the oat seeds by a two-step dry-heating process step. In the method, the so obtained dormant naturally hulless oats are then malted for up to 5 days at an elevated temperature, without causing the oat kernels to germinate. These false malted but not germinated oats are then dried and used as is, or further processed or milled to produce food, feed, nutraceutical or personal care products or ingredients thereof. As the false malting does not induce germination, the oat kernels have a similar morphology as the starting oat material, and are free of roots, coleoptiles and emerging leaves and shoots, enabling further processing of the oat material into various foods and feeds. If non-dormant oats are used, they are first subjected to induction or enhancement of dormancy, thus rendering the oats suitable for false malting. Also covered (hulled) oat can be used and subjected to dehulling after the false malting process, but the resulting increase in the avenanthramide concentrations is relatively low (~3 times versus 8 – 9 times for naked oat). The overall processing time for producing oats with increased avenanthramide concentration by the disclosed method is long (~13 – 15 days for the steps of introducing the secondary dormancy and false malting only) and involves complex processing steps such as chemical sterilization and use of anaerobic steeping conditions, altogether dramatically increasing the overall costs of the obtained oat material.

[0006] WO 2020 / 065089 discloses a consumable product comprising malted dehulled oats and / or a leachate of malted dehulled oats, wherein said consumable product induces endogenous production of antisecretory factor (AF) protein and / or fragments thereof in a subject after consumption. The malted dehulled oats comprised in the consumable products disclosed are produced by a malting process including germination at a temperature from 5°C to 20°C for 5 to 9 days after a wet steeping of the dehulled oat kernels at a temperature from 5°C to 20°C for 1–5 days. The malted dehulled oats and / or a leachate of the malted dehulled oats comprised in the consumable product comprises (i) avenanthramide D (avenanthramide 1p) in a concentration higher than in the corresponding non-malted dehulled oats, and optionally one or more of the compounds selected from the group consisting of (ii) avenanthramide A (avenanthramide 2p), (iii) avenathramide C (avenanthramide 2c), (iv) avenanthramide C methyl ester, (v) (Z)-N-feruloyl 5- hydroxyanthranilic acid, (vi) avenanthramide G (avenanthramide 4p), and (vii) a compound selected from the group consisting of guaiacol or a derivative thereof, L-tryptophan, DL-phenylalanine, and any combination thereof, wherein the concentration of one or more of (ii-vii) is higher as compared to in the corresponding non-malted dehulled oats. Notably, no comparisons to intact, non-dehulled oats malted by a corresponding malting process are made. The prolonged germination is expected to partly hydrolyse the starch and render the resulting germinated oat kernel fragile and difficult to process into conventional oat products.SUMMARY

[0007] The invention relates to a method of increasing avenanthramide content in oats as set forth in independent claim 1, oat material obtainable by said method as set forth in independent claim 9, and to a consumable product containing said oat material as set forth in independent claim 10.

[0008] Some embodiments of the invention are set forth in the dependent claims. Further embodiments and aspects of the invention become apparent from the detailed description, the drawings and the examples.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] is a graph showing germination energies for different hulled and dehulled oat samples.

[0010] is a photograph demonstrating visual differences in the germination of hulled and dehulled oat grains.

[0011] shows a concentration sum of avenanthramides 2c, 2p and 2f per fresh weight in hulled and dehulled oat grains with or without bioactivation as described in Example 2.

[0012] shows results of a DPPH antioxidant assay. The smaller the EC50 value, the higher the total antioxidativity of the sample.

[0013] shows total DNA levels ofFusariumspecies, as well as DNA levels ofF. graminearumandF. culmorumin hulled and dehulled oat grains with or without bioactivation.

[0014] shows a deoxynivalenol (DON) content in hulled and dehulled oat grains with or without bioactivation.

[0015] illustrates avenanthramide contents in dehulled oat grains germinated as described in Example 3. Shown are concentrations for avenanthramides 2c+2d+2f, avenanthramide 2pd(i.e. avenanthramide O according to the Collins nomenclature), and the sum of the remaining avenanthramides. The results are given per 100g of dry weight.

[0016] shows the contents of the detected and identified avenanthramides. The results are given per 100g of dry weight. AVN, avenantramide type I; AVL, avenanthramide type II (avenalumin).

[0017] andshow the energy and nutrient contents of the dehulled oats before and after bioactivation, respectively. The results are given per 100g of dry weight.DEFINITIONS

[0018] Unless otherwise defined, terms and expressions used in this specification and in the claims have the meanings generally applicable in the field to which the invention belongs. Some of the terms and expressions used herein have the meanings defined below. Further definitions may appear later in the detailed description.

[0019] As used herein, the singular expressions “a”, “an” and “the” mean one or more. Thus, a singular noun, unless otherwise specified, carries also the meaning of the corresponding plural noun.

[0020] As used herein, the term “and / or” in a phrase such as “X and / or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning.

[0021] As used herein, the term ”dehulling” refers to a process of removing the outermost protective layer of the oat grain (i.e. kernel or seed) known as the hull or husk. Accordingly, the term “dehulled oats” refers to oats from which the hull has been removed. Dehulled oat grains may also be called as "groats".

[0022] As used herein, the term ”hulled oats” refers to intact oat grains covered by the hull or husk. Such grains have not undergone a dehulling process and may, therefore, also be called as “non-dehulled” grains.

[0023] In the context of the present disclosure, the terms “hulless” or “naked” oats refer to oat varieties that lack the hull present on common oats, or to oat grains derived from such varieties. Non-limiting examples of naked oat varieties include VAO-2 and VAO-48.

[0024] As used herein, the term “steeping” refers to a process in which grains are supplied with water to provide a suitable moisture content therein by imbibition to enable germination.

[0025] As used herein, the term “germination” refers to a first phase of the growth cycle in plants, culminating in the emergence of a sprout from a grain. Herein, the terms “germination” and “sprouting” may be used interchangeably, unless dictated otherwise.

[0026] As used herein, the term “malting” refers to a process of converting cereal grains into malt. Generally, the malting process comprises at least three stages, namely steeping, germination and drying stages. In a malting process, the germination stage aims at complete or almost complete degradation of the grains’ starch reserves into sugars.

[0027] As used herein, the term “bioactivation” refers to a beginning of an abnormal germination process, more specifically to a phase where various biochemical processes in the oat groats are initiated without normal sprouting and substantial degradation of starch.DETAILED DESCRIPTION

[0028] The present disclosure provides a method of increasing avenanthramide content in oats. It is already known that germination increases avenanthramide content in oat grains, but it has now been unexpectedly realized that the avenanthramide content can be increased even without conventional germination, through short bioactivation of dehulled oats.

[0029] The first step of the present process is dehulling of oat grains. The dehulling may be carried out by any appropriate technique or equipment known to those skilled in the art, including but not limited to the use of a dehuller, such as an impact dehuller. Although industrial dehullers may sometimes be preferred, dehulling may also be carried out using a laboratory dehuller.

[0030] Loose hulls (i.e. the hulls detached from the grains by dehulling) may be separated from the dehulled grain stream by air aspiration or any other appropriate technique available in the art. Purity of the dehulled grain stream may be increased by passing said stream onto a paddy table or any other oscillating gravity separator resulting in efficient removal of any hulled grains remaining in the dehulled grain stream. In some embodiments, broken grains and other small grain pieces may be removed from the dehulled oat grains, for example by using air aspiration, drum sorting, optical sorting, or any combination thereof, as is well known to those skilled in the art.

[0031] Preferably, the dehulled seeds should be subjected to the next steps of the present method as soon after the dehulling as possible, preferably within 6 days, more preferably within 5 days, 4 days, 3 days, 2 days or within 1 day. The shorter the elapsed time, usually the less factors that could potentially have an adverse effect on the quality and organoleptic properties of the dehulled seeds. For example, oxidation of fatty acids increases over time, resulting in unpalatable lipid oxidation products.

[0032] After dehulling and optional removal of broken grains, the oat groats are steeped with an aqueous solution, such as water, to provide them with a bioactivation-enabling moisture content. Too low a moisture content prevents the groats from bioactivation, whereas too high a moisture content not only increases the risk of spoilage but also provides acidic taste to the bioactivated groats, a feature that adversely affects consumer acceptance. Moreover, the moisture content is proportional to the softness of the groats, excess softness complicating further processing of the bioactivated groats. In view of these issues, a suitable moisture content for the steeped dehulled oat groats ranges from 35% to 40% by weight, or between any values within this range, such as 36-39% by weight. In a specific embodiment, the moisture content of the steeped dehulled oat groats is 38% by weight.

[0033] The steeping may be carried out at temperatures varying between about 12°C and about 18°C, including any subranges and point values within this range, such as about 14-16°C or about 15°C, optionally in alternating conditions typically for a total of about 10-20 hours. Said alternating conditions may include not only alternating steeping temperatures but also alternating moisture conditions, namely alternating wet steeping and dry steeping steps. The wet steeping may be carried out by soaking the groats in or spraying them with an aqueous solution such as water with or without additional substances including, but not limited to, hydrogen peroxide and antimicrobial agents such as acids. During the dry steeping, the groats are allowed to air-rest in dry conditions. In an embodiment, the steeping step comprises a sequence of soaking in or spraying with an aqueous solution such as water for about 2 hours, air-rest for about 8 hours, followed by soaking in or spraying with an aqueous solution such as water for about 1-2 hours, such as about 1.5 hours, at a temperature of about 12-18°C, about 14-16°C or about 15°C. In another embodiment, the steeping step comprises soaking in or spraying with an aqueous solution such as water for about 6 hours, air-rest for about 8 hours, followed by soaking in or spraying with and aqueous solution such as water for about 5 hours, at a temperature of about 12-18°C, about 14-16°C or about 15°C. Although employing alternating wet and dry steeping steps may at least in some instances be beneficial, steeping of the groats may also be carried out in wet conditions only, with or without replacing the aqueous steeping solution with a fresh one any desired number of times during the steeping. A switch from wet steeping to possible dry steeping may involve draining of the steeping solution, but it may also be effected by any other suitable means. Likewise, the steeping may include draining or removal of the steeping solution by any other suitable means at the end of the steeping step. Notably, the steeping may also be implemented in any other way and / or in any other conditions as long as the moisture content defined above is achieved.

[0034] After steeping to a desired moisture content disclosed above, either by using the conditions exemplified above or achieved in any other way, the oat groats are bioactivated for about 1 to about 3 days at a temperature ranging from about 10°C to about 20°C, including any subranges and point values within this range, such as about 15-18°C, about 18°C or about 15°C, in any alternating combinations. The present bioactivation phase differs from a germination phase of a conventional malting process at least with respect to the duration and purpose of the germination phase. In malting, the hulled grains are typically germinated for at least about 4 to about 6 days with an aim to achieve complete or nearly complete degradation of starch into sugars. In the present method, in turn, the purpose of the bioactivation is to initiate various biochemical processes in the dehulled groats without complete degradation of starch. At least owing to a clearly shorter duration, the present process is distinct from and should not be referred to as a “malting process” or as “germination” or “sprouting”.

[0035] In an embodiment, steeped dehulled oat groats are bioactivated at about 15°C for about 1 to about 3 days, such as for about 2 days, about 2.5 days or for about 3 days. In another embodiment, steeped dehulled oat groats are bioactivated first at about 18°C for about 0.5-2 days, followed by another about 0.5-2 days at about 15°C, such that the overall bioactivation time does not exceed about 3 days, the total bioactivation time being in some particular embodiments about 2 or about 2.5 days in total. In an embodiment, steeped dehulled oat groats are first bioactivated at about 18°C for about 1 day, followed by another about 1 day at about 15°C.

[0036] Bioactivation times longer than those set forth above may turn the oats into malt, an outcome that is to be avoided for various reasons, including but not limited to higher risk for spoilage, adverse organoleptic properties, such as sour taste, and adverse effects on suitability for further processing. Moreover, the longer the duration of the process, the higher the expenses and lower the cost efficiency.

[0037] After bioactivation, the groats are heat-treated, and thus dried, preferably to a moisture content ranging from about 5% to about 15% by weight, preferably ranging from about 10% to about 12% by weight, more preferably to about 12% by weight. The heat treatment stops the bioactivation and prevents the grains from turning into malt. The heat treatment also inactivates lipases and other enzymes in the bioactivated groats, thereby preventing, for example, rancidification during storage. The heat treatment step has also an impact on the taste of the resulting product, for example by providing roasted taste.

[0038] Heat treatment of the bioactivated groats to a desired moisture content may be achieved by various techniques using various processing conditions. For example, the heat treatment may be carried out in a drum dryer at temperatures gradually increasing to about 90-100°C, preferably to about 95-100°C, in a linear or stepwise manner. This may be done over several hours, such as over about 1-4 hours, preferably over about 2-3 hours. In an embodiment, the bioactivated groats are first heat-treated to a moisture content of about 17-18% by weight, followed by a steam treatment at about 100°C for about 30-60 min, such as for about 45 min, followed by a heat treatment at about 90-100°C, preferably at about 95°C, to a final moisture content of about 10-12%, i.e. a moisture content suitable for storage.

[0039] The present method results in significantly increased amounts of avenanthramides in the resulting oats with a bioactivation that is markedly shorter than conventional germination. Germination of hulled oats as such is known to affect the avenanthramide composition of oats, but it has now been unexpectedly realized that dehulling of the oats significantly increases their avenanthramide content even after a short bioactivation time.

[0040] In an embodiment, the present bioactivation method increases the total avenanthramide content of dehulled oats to at least about 500 mg / kg, preferably to at least about 600 mg / kg, more preferably to at least about 700 mg / kg, even more preferably to at least about 800 mg / kg, still more preferably to at least about 900 mg / kg, and even still more preferably to at least about 1000 mg / kg, all values being on dry weight basis.

[0041] In an embodiment, the present bioactivation method increases the sum of the three main avenanthramides, namely the sum of avenanthramides 2c, 2p and 2f, in dehulled oats to at least about 300 mg / kg, preferably to at least about 400 mg / kg, more preferably to at least about 500 mg / kg, and even more preferably to at least about 600 mg / kg, all values being on dry weight basis.

[0042] In an embodiment, the present bioactivation method increases the amount of avenalumin 2pd in dehulled oats to at least about 100 mg / kg, preferably to at least about 200 mg / kg, the values being on dry weight basis.

[0043] In accordance with what is disclosed above, also provided herein is bioactivated dehulled oats or oat materials with increased avenanthramide content, which oats or oat materials are obtainable by the method disclosed herein. The oats or oat materials so obtained may be processed further, for example, by milling or flaking and / or by converting said oats or oat materials into various consumables. Notably, the bioactivation according to the present disclosure, does not cause adverse effects that would prevent or complicate said further processing or conversion into various consumables.

[0044] Accordingly, the present disclosure also provides consumables comprising material derived from oats bioactivated in accordance with the present method. Examples of such consumables include, but are not limited to, oat flakes, oat flour, non-dairy products such as oat drinks and fermented or non-fermented spoonable products, and bakery products such as breads, cookies, biscuits, pastries, and snack bars.EXAMPLE 1

[0045] Hulled and dehulled oat grains of three different oat varieties, namely Matty, Peppi and Belinda, were used for determining their germination capacity on petri dishes using conditions generally applied for barley (germination energy assay, EBC 3.7). Initially, increase in the germination energy of the dehulled seeds was slower than that of the hulled seeds but after three days, no significant differences in the germination energies were detected, except for Belinda (). However, there was a clear visual difference between the hulled and dehulled seeds. The hulled seeds were primarily characterized by the emergence of radicles whereas the dehulled seeds were primarily characterized by the emergence of coleoptiles ().EXAMPLE 2

[0046] In this experiment, hulled and dehulled Peppi and Matty varieties were used. Because the hulled seeds absorbed water more efficiently than the dehulled seeds, slightly different steeping protocols were employed in order to achieve corresponding moisture contents for both sample types. To this end, the dehulled seeds were first subjected to wet steeping for 2 hour, then to dry steeping (i.e. air-resting) for 8 hours and finally to a second wet steeping for 75 min, whereas the hulled seeds were first subjected to wet steeping for 90 min, then to dry steeping for 8 hours and finally to a second wet stepping for 15 min. All the steeping steps were carried out at 15°C.

[0047] After steeping, the hulled and dehulled seeds were set into an automated germinator device for 2, 3 or 5 days at 15°C followed by drying to a moisture content of 10% by weight, by first raising the temperature to 65°C during 30 min, then by maintaining the 65°C for 10 min, followed by raising the temperature to 100°C during 30 min, and finally by maintaining the 100°C for 90 min.

[0048] After the heat-treatment, the seeds were analysed for their avenanthramide contents at Natural Resources Institute Finland. A clear difference was observed in the starting levels of avenanthramides between different varieties. For example, the sum of the main three avenanthramides (2c+2p+2f) was significantly higher in Peppi than in Matty (67-78 mg / kg vs. 17-19 mg / kg). Bioactivation increased the 2c+2p+2f content in all the samples, but the increase was many times greater in the dehulled samples than in the hulled (i.e. non-dehulled) ones. The highest 2c+2p+2f content (ca. 616 mg / kg) was measured from dehulled Peppi samples that were bioactivated for 3 days and freeze-dried immediately after the bioactivation. Subjecting corresponding samples to a heat drying process after the bioactivation reduced the 2c+2p+2f content to ca. 456 mg / kg. Matty samples did not measure equally high concentrations, but taking into account the lower starting level, the increase in the 2c+2p+2f content was even stronger in Matty samples than in Peppi samples. The 2c+2p+2f content of heat-treated samples is shown in.

[0049] Total antioxidant activities of the oat samples were determined by a conventional 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The results expressed as EC50 (mg / ml), i.e. as the concentration of the oat samples required to cause 50% DPPH inhibition values, are shown in. The lower the EC50 value, the higher the total antioxidant activity of the sample. According to the results, bioactivation increased the antioxidant activity of the samples linearly, being the higher the longer the bioactivation had lasted. Overall, bioactivated samples from the dehulled oats had higher DPPH radical scavenging activities than bioactivated samples from the hulled oats, for both oat varieties studied.

[0050] The greatest single safety risk associated with bioactivated, germinated or malted oats relates to mycotoxins and especially to the deoxynivalenol (DON) mycotoxin produced byFusariummoulds. For example, the EU legislation has set maximum limits for DON for both raw oats (1750 μg / kg) and several end products such as flakes and flour (750 μg / kg). Growth ofFusariumand production of mycotoxins were considered as potential risk factors in the present bioactivation process, which is why samples were analysed for the total DNA ofFusariummoulds and for mycotoxins such as DON. The results showed that in the hulled samples, the total DNA ofFusariummoulds decreased in response to steeping and initiation of the bioactivation, but increased to high levels at the end of extended bioactivation (5 days). Importantly, both the initial levels and the levels after the bioactivation remained very low in the dehulled samples (). The mycotoxin analyses showed that DON was the only mycotoxin present in significant concentrations in the hulled samples, and that its concentrations increased during bioactivation. However, the DON concentrations were considerably lower in the dehulled samples, and clearly below the limits of the EU legislation (), also after extended bioactivation. To conclude, the bioactivated dehulled oats proved to be microbiologically safer than the corresponding bioactivated hulled oats.EXAMPLE 3

[0051] In this example, non-kilned (non-heat treated) oat grains were first dehulled in an industrial dehulling process at Nokia Mill, Finland. After two (batch 1A) or eight days (batch 1B), the groats were soaked as follows: 6h wet soak; 12h dry soak; 7h wet soak to reach the moisture level of 43% (batch 1A) or 42% (batch 1B). Next, the soaked groats were transferred into a malting drum in which they were bioactivated for one day at 18 °C and additional 2.5 days at 15 °C. Next, the bioactivated groats were dried at max 100 °C temperature, and further flaked to produce a consumer product, oat flakes. Surprisingly, a 3.5-day bioactivation time formed a strong acidity and therefore the process needed further optimization.

[0052] Next, the bioactivation method was further optimized and the bioactivation time was drastically shortened to avoid the acidic taste, to increase microbiological safety and to enhance production efficiency. Therefore, the dehulled oats were bioactivated only for 1 and 2 days.

[0053] First, the non-kilned oat grains were dehulled in an industrial dehulling process at Nokia Mill, Finland. After two (batch 2A) or 6 days (batch 2B), the groats were soaked followingly: 6h wet soak; 8h dry soak; 5h wet soak to reach the moisture level of 42% (batch 2A) or 38% (batch 2B). Next, the soaked oat groats were transferred into a malting drum in which they were bioactivated for one day at 18 °C and an additional day at 15 °C. Next, the bioactivated oats groats were dried at max 100 °C temperature, and further flaked to produce a consumer product, oat flakes. During the shortened bioactivation, acidic notes were formed only in the batch 2A, which was more moist. Surprisingly, decreasing the moisture level below the conventional moisture levels used for grains, and decreasing the bioactivating time, resulted in no acidity note.

[0054] Next, the avenanthramide levels of the bioactivated batches 2A and 2B were measured (Figures 7 and 8). Surprisingly, the 1-day bioactivation resulted in significantly increased total avenanthramide levels compared to the non-bioactivated native oat, and the second day of bioactivation caused a further, yet modest, increase. The drier moisture level of the oats (38%) lead to a higher level rise of the avenanthramides compared to the conventional moisture level of 42%, which was surprising.

[0055] Moreover, the content of the main three avenanthramides (2c+2p+2f) increased surprisingly by a factor of ca. 13 times (1 231 %) already after one day of bioactivation compared to the non-bioactivated native oat kernels, whereas after the second day of bioactivation, the value was 1.5 times (55 %) more (). The highest increase for a single avenanthramide was detected for avenalumin 2pd(avenanthramide O), which was increased by a factor of ca. 69 after one day of bioactivation (6787 %) and by factor of 1.8 after the second day of bioactivation (85%). Avenanthramide 4p (G) increased 21 times more after one day of bioactivation, whereas the second day of bioactivation increased its concentration by 20 %.

[0056] Interestingly, no avenanthramide D (avenanthramide 1p) was detected.

[0057] andreveal that the present rapid bioactivation method has only a modest effect on the nutrient contents of the bioactivated groats, indicating that the method does not cause nutritional change.

Claims

A method of increasing avenanthramide content in oats, the method comprising:dehulling oat grains;steeping the dehulled oat grains to a moisture content ranging from 35% to 40% by weight;bioactivating the steeped dehulled oat grains at a temperature ranging from 10°C to 20°C for 1 to 3 days; andheat-treating the bioactivated dehulled oat grains to a moisture content ranging from 5% to 15% by weight, preferably 10-12%, more preferably 12%;wherein the avenanthramide content in the bioactivated dehulled oats is higher than in corresponding bioactivated non-dehulled oats.The method according to claim 1, wherein the avenanthramide content refers to the total avenanthramide content, which is preferably at least 500 mg / kg, more preferably at least 600 mg / kg, even more preferably at least 700 mg / kg, still more preferably at least 800 mg / kg, even still more preferably at least 900 mg / kg, and even still more preferably at least 1000 mg / kg, calculated on dry weight basis.The method according to claim 1 or 2, wherein the avenanthramide content refers to the sum of avenanthramides 2c, 2d, and 2f, which is preferably at least 300 mg / kg, more preferably at least 400 mg / kg, even more preferably at least 500 mg / kg, and still more preferably at least 600 mg / kg, calculated on dry weight basis.The method according to any one of claims 1–3, wherein the avenanthramide content refers to the content of avenalumin 2pd, which is preferably at least 100 mg / kg, more preferably at least 200 mg / kg, calculated on dry weight basis.The method according to any one of claims 1–4, wherein the moisture content of the dehulled oat grains at the end of the steeping is 38% by weight.The method according to any one of claims 1–5, wherein the steeping step comprises soaking the dehulled oat grains in water for 2 to 6 hours, followed by air-rest for 6-10 hours, preferably for 8 hours, followed soaking in water for 1 to 6 hours, followed by draining.The method according to any one of claims 1–6, wherein the steeping step is carried out a temperature ranging from 12-18, preferably 15°C.The method according to any one of claims 1–7, wherein the bioactivation step comprises bioactivating the steeped dehulled oat grains for one day at 18°C and then another one day at 15°C.Oat material obtainable by the method according to any one of claims 1–8.A consumable product comprising the oat material according to claim 9.The consumable product according to claim 10, wherein the product is selected from the group consisting of oat flakes, oat flours, oat drinks, spoonables, and bakery products such as breads, cookies, biscuits, pastries, and snack bars.

Images