Compendium of the most significant studies with reference to properties, intake, effects.
Dhakal H, Yang EJ, Lee S, Kim MJ, Baek MC, Lee B, Park PH, Kwon TK, Khang D, Song KS, Kim SH. Avenanthramide C from germinated oats exhibits anti-allergic inflammatory effects in mast cells. Sci Rep. 2019 May 3;9(1):6884. doi: 10.1038/s41598-019-43412-2.
Abstract. Mast cells play a crucial role in allergic diseases via the release of inflammatory mediators, particularly histamine and pro-inflammatory cytokines. Avenanthramide (Avn) C, a polyphenol found mainly in oats, is known to exhibit various biological properties. In this study, we aimed to evaluate the effectiveness of Avn C from germinated oats against mast cell-mediated allergic inflammation. For the in vitro study, RBL-2H3, mouse bone marrow-derived mast cells and rat peritoneal mast cells were used. Avn C (1-100 nM) inhibited the immunoglobulin (Ig)E-stimulated mast cells degranulation by suppressing phosphorylation of phosphoinositide 3-kinase and phospholipase Cγ1 and decreasing intracellular calcium levels. It inhibited IgE-stimulated secretion of inflammatory cytokines via suppression of FcεRI-mediated signaling proteins Lyn, Syk, Akt, and nuclear factor-κB. To verify the effects of Avn C in vivo, ovalbumin-induced active systemic anaphylaxis (ASA) and IgE-mediated passive cutaneous anaphylaxis (PCA) models were used. Oral administration of Avn C dose-dependently attenuated the ASA reactions, as evidenced by the inhibition of hypothermia and reduction of elevated serum histamine, IgE, and interleukin-4 levels. Avn C also inhibited the PCA reactions, such as ear swelling and plasma extravasation. Our results suggested that Avn C from germinated oats might be a possible therapeutic candidate for mast cell-mediated allergic inflammation.
McGorrin RJ. Key Aroma Compounds in Oats and Oat Cereals. J Agric Food Chem. 2019 Dec 18;67(50):13778-13789. doi: 10.1021/acs.jafc.9b00994.
Abstract. Oats possess a unique flavor, comprising grain and nut-like sensory characteristics. The first comprehensive study of oat flavor by Heydanek and McGorrin [ Heydanek , M. G. ; McGorrin , R. J. Gas chromatography-mass spectroscopy investigations on the flavor chemistry of oat groats . J. Agric. Food Chem. 1981 , 29 ( 5 ), 950 - 954 , 10.1021/jf00107a016 ] identified 110 volatile components in oat groats, including C8-C9 unsaturated aldehydes and ketones contributing raw oat grain, hay-feedy, and grassy aromas. A following study on heat-processed oats and cooked oatmeal by Heydanek and McGorrin ( Heydanek , M. G. ; McGorrin , R. J. Oat flavor chemistry: Principles and prospects . In Oats: Chemistry and Technology , 1 st ed.; Webster , F. H. , Ed.; AACC International : St. Paul, MN , 1986 ; pp 335 - 369 ) identified a series of Maillard-derived compounds, including furanones, thiazoles, and 2-methyl-, 2,5-dimethyl-, C3-, and C4-substituted pyrazines. In the subsequent 38 years since these initial research findings, additional identifications of aroma compounds in oat flakes and flours have been reported. This review addresses significant recent developments of the current understanding of oat flavor chemistry and the key aroma compounds that contribute to the unique flavor of oat cereals.
Gilissen LJWJ, van der Meer IM, Smulders MJM. Why Oats Are Safe and Healthy for Celiac Disease Patients. Med Sci (Basel). 2016 Nov 26;4(4):21. doi: 10.3390/medsci4040021.
Abstract. The water-insoluble storage proteins of cereals (prolamins) are called "gluten" in wheat, barley, and rye, and "avenins" in oat. Gluten can provoke celiac disease (CD) in genetically susceptible individuals (those with human leukocyte antigen (HLA)-DQ2 or HLA-DQ8 serotypes). Avenins are present at a lower concentration (10%-15% of total protein content) in oat as compared to gluten in wheat (80%-85%). The avenins in the genus Avena (cultivated oat as well as various wild species of which gene bank accessions were analyzed) are free of the known CD immunogenic epitopes from wheat, barley, and rye. T cells that recognize avenin-specific epitopes have been found very rarely in CD patients. CD patients that consume oats daily do not show significantly increased levels of intraepithelial lymphocyte (EIL) cells. The safety and the positive health effects of the long-term inclusion of oats in the gluten-free diet have been confirmed in long-term studies. Since 2009 (EC 41/2009) and 2013 (FDA) oat products may be sold as gluten-free in several countries provided a gluten contamination level below 20 ppm. Introduction of oats in the gluten-free diet of celiac patients is advised after the recovery of the intestine. Health effects of oat consumption are reflected in European Food Safety Authority (EFSA)- and Food and Drug Administration (FDA)-approved health claims. Oats can form a healthy, nutritious, fiber-rich, and safe complement to the gluten-free diet.
Kosová K, Leišová-Svobodová L, Dvořáček V. Oats as a Safe Alternative to Triticeae Cereals for People Suffering from Celiac Disease? A Review. Plant Foods Hum Nutr. 2020 Jun;75(2):131-141. doi: 10.1007/s11130-020-00800-8.
Abstract. Oats represent a promising alternative to small-grain cereals from Triticeae group (wheat, barley, rye) for persons suffering from any form of gluten intolerance, especially celiac disease (CD), since oat-specific prolamins avenins reveal generally lower gluten content and immunoreactivity. Recent studies on avenin molecular structure revealed large genetic variability in avenin sequences affecting the spectrum of gluten peptides produced by hydrolases in human digestive tract. The aim of the present review is to summarise recent knowledge obtained in laboratory studies focused on the effect of avenin-derived peptides on reactivity of crucial components of human immune system such as dendritic cells (DC) and T-cells. The other part of the review summarises the results of clinical studies with CD patients including oat products in their diet. Since different clinical studies revealed contradictory results regarding potential safety of oats for CD patients, the focus has to be directed at genetic variability in oat avenins. Identification of avenin isoforms with minimum CD immunoreactivity will open up ways leading to designing novel oat cultivars suitable for CD patients. Knowledge on immunoreactivity of gluten peptides together with breeding new oat cultivars revealing minimum avenin immunoreactivity with respect to CD as well as application of food processing technologies leading to gluten content reduction should result in development of gluten-free oats safe for celiacs.
Dong JL, Yang M, Shen RL, Zhai YF, Yu X, Wang Z. Effects of thermal processing on the structural and functional properties of soluble dietary fiber from whole grain oats. Food Sci Technol Int. 2019 Jun;25(4):282-294. doi: 10.1177/1082013218817705.
Abstract. Normal pressure steaming, high pressure steaming, microwave, and frying are widely used to deactivate enzyme in the oats, but these thermal processing methods may affect the structural and functional properties of soluble dietary fiber, which contribute greatly to the health benefits of oat foods. The objective of this study was to evaluate the effects of four different thermal processing methods on the structural and functional properties of soluble dietary fiber from whole grain oats. The results showed that the thermal processing resulted in changes on nutritional components of whole grain oats. Especially dietary fiber components, the total dietary fiber, insoluble dietary fiber, and soluble dietary fiber content of heat-treated oats were significantly increased ( p < 0.05). Moreover, thermal processing can not only result in an increase in molecular weight and particle size, but also cause molecular aggregation and different functional properties of soluble dietary fiber. High pressure steaming-treated oat soluble dietary fiber displayed significantly higher swelling and emulsifying ( p < 0.05), but microwave-treated oat soluble dietary fiber exhibited the highest glucose, cholesterol, and sodium cholate adsorption capacities. These results might provide basic information to help to better understand the functionality of oat soluble dietary fiber and improve the process efficiency of oat foods with high nutritional qualities.
Sargautiene V, Nakurte I, Nikolajeva V. Broad Prebiotic Potential of Non-starch Polysaccharides from Oats (Avena sativa L.): an in vitro Study. Pol J Microbiol. 2018;67(3):307-313. doi: 10.21307/pjm-2018-036.
Abstract. Prebiotics inducing the growth or activity of beneficial intestinal bacteria - probiotics producing short-chain fatty acids (SCFA) have lately received wide recognition for their beneficial influence on host intestinal microbiota and metabolic health. Some non-starch polysaccharides (NSP) are defined as prebiotics and oats being one of richest sources of NSP in grains are considered as potentially having prebiotic effect. However, information on fermentation of specific NSP of oats is limited. Moreover, bacterial cross-feeding interactions in which fermentation of prebiotics is involved is poorly characterized. Here, we report the exploration of new candidates for the syntrophic bacterial interactions and fermentability of oat non-starch polysaccharides (NSP). The results obtained by differentiating composition, viscosity and concentration of oats NSP in fermentation medium showed that Bacillus licheniformis pre-digests oat NSP, degrades high viscosity of oat β-glucan and makes hemicellulose easier to access for other bacteria. Because of fermentation, B. licheniformis produces lactic and succinic acids, which further can be used by other bacteria for cross-feeding and SCFA production. © 2018 Vanda Sargautiene et al.
Wolever TMS, Jones PJH, Jenkins AL, Mollard RC, Wang H, Johnston A, Johnson J, Chu Y. Glycaemic and insulinaemic impact of oats soaked overnight in milk vs. cream of rice with and without sugar, nuts, and seeds: a randomized, controlled trial. Eur J Clin Nutr. 2019 Jan;73(1):86-93. doi: 10.1038/s41430-018-0329-1.
Abstract. Background/objectives: Soaking oats overnight in milk renders them ready to eat the next morning, however, it is unknown whether oats prepared this way will retain its relatively low glycaemic and insulinaemic impact. Therefore, we compared the glycaemic, insulinaemic and subjective hunger responses elicited by oats soaked overnight in 110 g skim-milk (ONO) vs. cooked cream of rice cereal (CR), both with and without inclusions....Conclusions: Oats prepared by soaking overnight in skimmed milk without and with inclusions retain their relatively low glycaemic and insulinaemic impact.
Angelov A, Yaneva-Marinova T, Gotcheva V. Oats as a matrix of choice for developing fermented functional beverages. J Food Sci Technol. 2018 Jul;55(7):2351-2360. doi: 10.1007/s13197-018-3186-y.
Abstract. Development of oat-based fermented beverages started in Europe in the past 30 years with the rise of the functional foods market. It is based on the increasing consumer demand for health drinks and value added foods and on the scientific insights on the nutrition composition of oats. The main health effects of oats are attributed to their high β-glucan content, which is proved to lower blood cholesterol and the intestinal absorption of glucose thus preventing diseases like cardiovascular injury, dyslipidemia, hypertension, inflammatory state and diabetes type 2. Another important role of β- glucan is its prebiotic function in the gastrointestinal tract, supporting the growth of beneficial microbial groups. The slowly digestible fraction of oat starch has a functional role as it moderates the glycaemic response. Oats are also a valuable source of highquality proteins, unsaturated lipids and antioxidants. In addition, oats are appropriate for people suffering from celiac disease because they do not contain gluten. Oat grain processing involves several steps, including thermal processes aiming to prevent oat products from rapid enzymatic deterioration and ensure storage stability. Oat drinks are formulated through processing oat with a liquid ingredient. Further, this matrix is inoculated with lactic acid bacteria to produce a fermented beverage. In some, drinks, probiotic lactic acid bacteria were used to increase product functional value. Thus, the ancient concept of cereal-based fermented foods is implemented into development of new functional oat-based fermented beverages and several products are already marketed in Europe as healthy, fast and convenient supplementary foods.
Oats 
Avenin
