Effect of Extrusion and Konjac Flour Addition on the Antioxidant Activity, Structural Properties, and in vitro Digestibility of Extruded Oat–Corn Flour

Effect of steam explosion on nutritional components, physicochemical and rheological properties of brown rice powder

Brown rice powder is underutilized mainly due to its lower starch digestibility and poor processing performance. The present study investigated the potential of steam explosion on the improvement of nutritional and physicochemical characteristic in brown rice powder and rheological property of paste. Compared with native brown rice powder, steam explosion at 0.5 MPa for 7 min increased the water-extractable arabinoxylans (5.77%), reducing sugar content (21.04%), and iodine blue value (30.38%), which indicated steam explosion that destroyed the intact cells of brown rice. Later the crystalline structure of brown rice powder was destroyed into an amorphous structure by steam explosion. Steam explosion enhanced the degree of gelatinization (4.76~351.85%) and solvent retention capacity (SRC) of brown rice powder, compared with native sample. The effect on the intact cells and starch structure of brown rice caused the starch digestibility enhancement remarkable. Viscoelastic profiles confirmed that steam explosion weakened the paste strength and elasticity corresponded with hardness and cohesiveness by increasing the loss factor (tanδ). This work provided important information for brown rice powder modified by steam explosion (0.5 MPa, 7 min) with good nutritional property (nutrients and digestibility) and processability (SRC, textural, and rheological property). Steam exploded brown rice powder (0.5 MPa, 7 min) could serve as a potential ingredient widely used in food products.

Improving bioaccessibility and physicochemical property of blue-grained wholemeal flour by steam explosion

Whole grain contains many health-promoting ingredients, but due to its poor bioaccessibility and processibility, it is not widely accepted by consumers. The steam explosion was exploited to modify the nutritional bioaccessibility and the physicochemical properties of wholemeal flour in this study. In vitro starch digestibility, in vitro protein digestibility of wholemeal flour, total flavonoids content, and total phenolics content of digestive juice were used to evaluate the bioaccessibility, and a significant variation (p < 0.05) was noted. Results showed that steam explosion enhanced the gastric protein digestibility ranged from 5.67 to 6.92% and the intestinal protein digestibility ranged from 16.77 to 49.12%. Steam-exploded wholemeal flour (0.5 MPa, 5 min) had the highest protein digestibility and rapidly digestible starch content. Compared with native flour, steam explosion (0.5 MPa, 5 min) contributed to a 0.72-fold and 0.33-fold increment of total flavonoids content and total phenolics content in digestible juice. Chemical changes of wholemeal flour, induced by steam explosion, caused the changes in the solvent retention capacity, rheological property of wholemeal flour, and altered the falling number (and liquefaction number). An increasing tendency to solid-like behavior and the gel strength of wholemeal flour was significantly enhanced by the steam explosion at 0.5 MPa for 5 min, while the gluten was not weakened. This study indicated that steam-exploded wholemeal flour (0.5 MPa, 5 min) could serve as a potential ingredient with the noticeable bioaccessibility and physicochemical properties in cereal products.

Effects of Oat Complex High-Fiber Formula Powder on the Composition of Intestinal Microbiota and Enzyme Activities in Mice Induced by a High-Fat Diet

Using oat-corn-konjac extruded mixed powder, oat bran micro powder, skim milk powder, Pueraria whole powder, and pumpkin powder as raw materials, a formula powder with high dietary fiber was prepared, and its effect on obesity in mice with a high-fat diet was investigated. After 7 days of adaptive feeding, the mice were divided into blank group, high-fat diet group, formula powder + high-fat diet group, and weight-loss drug + high-fat diet group. After 8 weeks of treatment, the body weight of mice were observed and measured to determine the composition of tract flora, liver leptin content, insulin content, and activities of AMP-activated protein kinase (AMPK), lipoprotein lipase (LPL), fatty acid synthetase (FAS), sterol-regulatory element-binding proteins (SREBPs), and acetyl CoA carboxylase 1 (ACC1). The results indicated that treatment with the formula powder could reduce the body weight of mice and increase the abundance of Bifidobacterium, Akkermansia, and Romboutsia compared to the group given a high-fat diet. Moreover, the leptin and insulin contents of the experimental group decreased from 5.67 μg/L to 0.12 μg/L and from 12.71 μg/L to 7.13 μg/L, respectively, compared to the control group, which was not significantly different from the blank group (P > 0.05). Also, the activities of AMPK and LPL increased, and the activities of FAS, SREBPs, and ACC1 were significantly decreased (P < 0.05). Some pathogenic bacteria were significantly positively correlated with leptin and FAS and significantly negatively correlated with LPL. Some beneficial bacteria were positively correlated with LPL. Therefore, the formula powder used in this study could reduce the body weight of mice, increase the abundance of some beneficial bacteria in the colonic intestinal microbiota, and improve the activities of enzymes related to lipid metabolism in the liver. This study provides a theoretical reference for the pathway by which high-fiber diet improves liver and intestinal metabolic abnormalities.