Wheat Roll Enhanced by Buckwheat Hull, a New Functional Food: Focus on the Retention of Bioactive Compounds.

Wheat roll enhanced by buckwheat hull was used as a model for determining the retention of bioactive compounds during technological steps. The research included analysis of the formation of Maillard reaction products (MRPs) and retention of bioactive compounds such as tocopherols, glutathione, or antioxidant capacity. About a 30% decrease in the content of available lysine in the roll was observed compared to the value obtained for fermented dough. Free FIC, FAST index, and browning index were highest for the final products. The increase of analyzed tocopherols (α-, ß-,γ-, and δ-T) was noticed during the technological steps, with the highest values found for the roll with 3% of buckwheat hull. A significant reduction in GSH and GSSG content occurred during the baking process. The observed increase in the value of the antioxidant capacity after the baking process may be the result of the formation of new antioxidant compounds.

Buckwheat Hull-Enriched Pasta: Physicochemical and Sensory Properties.

This work aimed to evaluate the effect of partial replacement of semolina with 0, 1, 5, 10, 15, and 20% of ground buckwheat hull (BH) on the chemical composition, antioxidant properties, color, cooking characteristics, and sensory properties of wheat pasta. Pasta samples were prepared by dough lamination (tagliatelle shape) and dried at 55 °C until the moisture content was 11-12% (wet basis). Analyses of samples showed that the addition of BH caused an increase in fiber content in pasta from 4.31% (control pasta) to 14.15% (pasta with 20% of BH). Moreover, the brightness and yellowness of BH-enriched products were significantly decreased compared to the control sample, and the total color difference ranged from 23.84 (pasta with 1% of BH) to 32.56 (pasta with 15% BH). In addition, a decrease in optimal cooking time, as well as an increased weight index and cooking loss, was observed in BH-enriched pasta samples. Furthermore, BH-enriched cooked pasta had significantly higher total phenolic content and antioxidant activity but an unpleasant smell and taste, especially if the level of BH was higher than 10%.

Flavonoids in common and tartary buckwheat hull extracts and antioxidant activity of the extracts against lipids in mayonnaise.

Buckwheat hulls, generally discarded as waste, have been known to possess various flavonoids and high antioxidant activities. The objective of this study was to determine effect of extracting solvents [water, ethanol (20%, 50%, 80%, and 100%), methanol, and acetone] on total phenolic content, flavonoid content and composition, and antioxidant activities of common and tartary buckwheat hull extracts. Antioxidative effect of common and tartary buckwheat hull extracts on lipids in mayonnaise was also investigated. Vitexin, isovitexin, isoorientin, orientin, rutin, isoquercetin, and quercetin were identified in the common buckwheat hull extracts, while rutin, quercetin, isoorientin, and isoquercetin were in the tartary buckwheat hull extracts. The methanol and 80% ethanol extracts had more flavonoids than the others, while the aqueous ethanol extracts from both of the hulls had more total phenolics and antioxidant activities. Oxidative stability of lipids in mayonnaises added with common and tartary buckwheat hull extracts (0.02 and 0.08%, w/w) prepared by 50% ethanol were higher than that in the mayonnaise with butylated hydroxytoluene (0.02%) and control. Oxidative stability was not significantly different between the mayonnaises added with the two buckwheat hull extracts.

Valorisation of Buckwheat By-Product as a Health-Promoting Ingredient Rich in Fibre for the Formulation of Gluten-Free Bread.

Bread is a widely consumed food that has often been used as a vehicle for functional ingredients such as dietary fibre. Fibre-rich breads have beneficial physiological effects on health, helping to combat chronic pathologies such as cardiovascular disease, diabetes, and certain types of colon cancer. The aim of this study is to evaluate the technological and nutritional effects of the inclusion of buckwheat hull particles (BH) at two addition levels (3 and 6%) and two particle sizes (fine, D50: 62.7 µm; coarse, D50: 307 µm) in a gluten-free (GF) bread formulation. A significant (p < 0.05) increase in the dough elastic modulus (G') was observed for all doughs containing BH, from 712 Pa for a rice-based dough to 1027-3738 Pa for those containing BH. Compared to rice-based breads, those containing BH showed a significant (p < 0.05) increase in total dietary fibre content (from three to five times) and in antioxidant capacity (from 78 to 290 mg TE/100 g dw. in the ORAC test). Breads containing fine BH at a level of 3% had similar sensory properties to the rice-based bread, demonstrating that it is possible to improve the TDF content while maintaining the sensory quality of the GF bread.

Hepatoprotective effects of flavonoids from common buckwheat hulls in type 2 diabetic rats and HepG2 cells.

Flavonoids from common buckwheat hulls (BHFs) show significant antioxidant and antidiabetic potential. However, their hepatoprotective property is yet to be defined. This study aims to examine the hepatoprotective effect of BHFs in type 2 diabetes mellitus (T2DM) rats and chronic high glucose-damaged HepG2 cells. Results showed that BHF treatment significantly relieves the state of insulin resistance, thereby reducing blood glucose and improving oxidative stress in T2DM rats. It is worth mentioning that BHF treatment improved diabetes-induced liver damage disorders, manifested as the clearance of liver fat and the decline of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. In vitro, HepG2 cells pretreated with BHFs maintained higher superoxide dismutase (SOD), glutathione peroxidase (GSH-px), and catalase (CAT) activities than the unprotected group. In parallel, compared with the unprotected group, BHFs significantly reduced the leakage of ALT and AST in pre-protected group dose-dependently. These results indicated that BHFs had considerable antioxidant and hepatoprotective potential and could be promising to be used as nutraceuticals and dietary supplements to prevent and/or protect against liver disorders.

Effects of pretreatment and type of hydrolysis on the composition, antioxidant potential and HepG2 cytotoxicity of bound polyphenols from Tartary buckwheat (Fagopyrum tataricum L. Gaerth) hulls.

This study investigated the effects of ultrasound assisted-subcritical water (U-SW), subcritical water (SW), ultrasound (U) and hot water (HW) pretreatments and acid hydrolysis (AH) and alkaline hydrolysis (AlkH) on the phenolic composition, antioxidant potential and cytotoxicity of Tartary buckwheat hull extracts. The Folin Ciocalteu assay and HPLC-MS were used to characterize and quantify phenolics of the extracts. The ABTS, FRAP and TEAC assays were used to measure antioxidant activity and the MTT assay was used to measure cytotoxicity of the extracts in HepG2 human liver cancer cells. Results showed that U-SW gave the best AH yield of phenolics (128.45), followed by SW (85.82) and U (64.70), compared to the control, HW (35.82 mgg-1). The same trend was observed for phenols extracted using AlkH. U-SW had the highest antioxidant activity, followed by SW and U regardless of hydrolytic method used. Cytotoxicity followed a similar trend with U-SW and SW being the most cytotoxic to liver cancer cells, followed by U, with the least being HW. The findings suggested that plant materials such as Tartary buckwheat hulls can be pretreated with U-SW, SW and U prior to hydrolytic recovery of bound polyphenols. Also, AH was more efficient than AlkH for phenol extraction, and gave extracts with higher antioxidant activity and cytotoxicity in HepG2 liver carcinoma cells. This application allows for beneficial usage of agricultural biomass and help diversify income sources and products for industry.

The Effect of Buckwheat Hull Extract on Lipid Oxidation in Frozen-Stored Meat Products.

This study investigated the effect of antioxidants on lipid stability of frozen-stored meat products. Buckwheat hull extract was used to enrich fried meatballs made from ground pork. During 180-d storage of meat products, lipid oxidation (peroxide and 2-thiobarbituric acid reactive substances [TBARS] value) was periodically monitored. The results were compared with butylated hydroxytoluene (BHT). The addition of antioxidants decreased lipid oxidation in stored meatballs. The highest ability to control peroxide and TBARS values was demonstrated for buckwheat hull extract. Moreover, buckwheat hull extract showed a higher 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity as well as higher Fe(II) ion chelating ability, as compared with BHT. The total content of phenolic compounds are highly correlated to the individual polyphenols in extract of buckwheat hull, among which the following were assayed: 3,4-dihydroxybenzoic acid, 4-hydroxybenzoic acid, gallic acid, isovanillic acid and p-coumaric acid, and flavonoids: isoorientin, quercetin, quercetin 3-d-glucoside, rutin, and vitexin. These results indicate that plant extracts can be used to prolong shelf life of products by protecting them against lipid oxidation and deterioration of their nutritional quality.

Green and efficient extraction of rutin from tartary buckwheat hull by using natural deep eutectic solvents.

In this study, an efficient extraction technique using a combination of ultrasound and natural deep eutectic solvents (NADESs) was developed. Some basic physical properties, including viscosity, polarity, and solubility, of thirteen NADESs prepared from natural components were investigated systematically. Results show that the solubility of rutin increased in choline chloride- and glycerol-based NADESs by 660-1577times compared to water. NADESs with high rutin extractability can be designed by combining NADESs components. A maximum of 9.5mg/g rutin was extracted from tartary buckwheat hull with extraction efficiencies of 95%. NADESs can be recovered and recycled. In addition, the biocompatibility and biodegradability of the tested NADESs were also evaluated. The results demonstrated that these NADESs were excellent solvents with extremely low toxicities and favorable biodegradabilities. Our findings suggest that NADESs can be used as green solvents for the extraction of bioactive ingredients.