Oat-Based Foods: Chemical Constituents, Glycemic Index, and the Effect of Processing

Abstract

The desire for foods with lower glycemic indices has led to the exploration of functional ingredients and novel food processing techniques. The glycemic index (GI) is a well-recognized tool to assess the capacity of foods to raise blood glucose levels. Among cereal crops, oats have shown the greatest promise for mitigating glycemic response. This review evaluated decades of research on the effects of oat components on the GI level of oat-based foods with specific emphasis on oat starch, β-glucans, proteins, and phenolics. The effects of commonly used processing techniques in oats on GI level, including heating, cooling, and germination were also discussed. In addition, the GI of oat-based foods in various physical formats such as whole grain, flakes, and flour was systematically summarized. The aim of this review was to synthesize knowledge of the field and to provide a deeper understanding of how the chemical composition and processing of oats affect GI, thereby further benefiting the development of low-GI oat foods.

Integrated Analysis of Metabolome and Volatile Profiles of Germinated Brown Rice from the Japonica and Indica Subspecies

“…The reduction of lipid contents observed in the present study were also in agreement with the previous reports for wheat [26] and brown rice [27]. On the contrary, the investigations on the germinated oat showed increased levels of lipids [24], which might be attributed to the unchanged or even declined levels of lipase activity during the sprout process [28]. Additionally, it is worth noting that the dynamic changes in the levels of the FFAs are also significantly affected by the sprouting conditions, e.g., temperature, moisture, and germination time [29].…”

“…As a result, a great number of metabolites such as fructose, glucose, alanine, valine, serine, and proline all presented much higher levels in GBR than in BR. Similar notable increases in the levels of sugars and amino acids were also reported in the germination course for wheat [21], barley [22], sorghum [23], and Oat [24]. On the contrary, the amounts of several major free fatty acids in BR, including stearic acid, oleic acid, and linoleic acid, were shown to have decreased in the GBR after germination.…”

Multiple Antioxidative and Bioactive Molecules of Oats (Avena sativa L.) in Human Health

“…As soluble dietary fibers have superior physiological functions, interest in oats with high soluble β-glucan content has increased. β-glucans in oats mainly consist of (1→3), (1→4)-beta- d -glucan, which is a linear polysaccharide, and this glucan is often abbreviated as β-glucan ( Figure 2 B) [ 41 , 42 ]. The health benefits of β-glucan in wheat and barley are relatively well-known [ 43 ].…”

“…Oat bran also contains high-quality proteins such as β-glucan, saponin, albumin, prolamins, and glutelins that lower cholesterol levels ( Figure 13 ) [ 148 , 149 , 150 , 151 , 152 ]. To date, studies on oats mainly assessed the nutritional value and processing characteristics of oat grains or powder [ 13 , 42 , 55 ]. There is a lack of studies on its by-products, such as the bran, hull, and leaves, which are mostly thrown away as waste during the processing [ 153 ].…”

“…There is a lack of studies on its by-products, such as the bran, hull, and leaves, which are mostly thrown away as waste during the processing [ 153 ]. However, as recent studies reported the content of numerous functional components in these by-products, the utility of oats is gradually increasing [ 42 , 55 ].…”