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Thermal sensitivity of anthocyanin and low‐water solubility of rutin limit their stability in processed foods and biological activity, respectively. Therefore, we aimed to develop a value‐added food composite (VAFC) by mixing of anthocyanin‐enriched potato (P) and rutin‐enriched buckwheat (B) flour using soy lecithin (LCT) and vitamin E (Vita E) by hot‐melt extrusion (HME). The VAFC was formulated using P 50% + B 50% (F1), P 45%+B 45%+LCT 10% (F2), and P 45%+B 45%+LCT 8%+Vita E 2% (F3). Results revealed that the solubility of the VAFC was significantly increased in F3 formulation. Likewise, total phenolic content, including single phenolic acids, total flavonoid including rutin and quercetin, total anthocyanin including single anthocyanins, and antioxidant capacity of the VAFC were significantly increased in F3 formulation. This study successfully demonstrated the approach of developing biopolymer‐mediated functional VAFC from potato and buckwheat by HME. Practical applications: People are becoming more conscious about daily consumed foods and their nutritional facts. Human health requires a well‐balanced nutritional composition to keep well‐functioning of the body. In this study, an approach was taken to develop anthocyanins, and rutin‐enriched functional food by the mixes of potato and buckwheat by hot‐melt extrusion. Food biopolymers and plasticizer were added to the food formulation to enhance the activity of the extrudate composites' functional attributes. Our developed formulation successfully improved the food composite's functional quality, which required industrialization for bulk production. [ABSTRACT FROM AUTHOR]

Buckwheat grain is a valuable source of various phytochemicals: health promoting flavonoids (rutin), as well as substances such as phototoxic fagopyrin. In this study, total fagopyrins, rutin, and quercetin were determined in Tartary buckwheat grains, milled fractions, and food products. HPLC was used for analyses; fagopyrins were detected by fluorescence, flavonoids by UV/VIS. After steaming, the fagopyrin content in the grain decreased. The remaining fagopyrins were unequally distributed; minor amounts were found in groats and higher concentration in hulls. Similarly, the concentration of rutin decreased, although to a lesser extent. Unlike fagopyrins, rutin was concentrated in groats. In the bread making procedure, a minor decrease of fagopyrins was seen comparing its concentration in grains, dough, and bread, while large amounts of rutin were degraded into quercetin during baking. Our results may stimulate further research on edible parts and products of buckwheat, particularly, the quantitative evaluation of total fagopyrin content in relation to flavonoids, providing information about the treatment process needed to prepare buckwheat products with the highest utilization value. [ABSTRACT FROM AUTHOR]

Abstract: The effects of far infrared irradiation (FIR) on total polyphenol (TP), total flavonoid (TF) content, antioxidant properties and aglycone quercetin production in tartary buckwheat sprout (TBS) were investigated. The study showed that FIR treatment decreased the total antioxidant capacity and metal chelating property in TBS in a temperature dependent manner, however, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity increased with the temperature. Similarly, TP and TF content also increased with temperature. The HPLC result revealed that quercetin production was directly proportional to the temperature, and the maximum production (average 14.8 mg/g dw) of quercetin was at 120 °C which was 13.5 times higher than the untreated control sample of TBS. Overall, this research is expected to be helpful to improve the nutritional value of tartary buckwheat by optimizing the FIR conditions. [Copyright &y& Elsevier]

Abstract: Tartary buckwheat seeds are highly nutritious and excellent dietary sources of phenolic compounds. Rice-tartary buckwheat is a special type of tartary buckwheat with a non-adhering hull trait. Here, we investigated the levels of expression of genes involved in the flavonoid biosynthetic pathway in common tartary and rice-tartary buckwheat. The flavonoid biosynthetic genes, from FtPAL to FtANS, showed different expression levels, especially in the reproductive organs of the 2 cultivars. The transcription levels of these genes, except FtC4H and FtANS, were higher in the mature seeds of rice-tartary buckwheat than in those of common buckwheat. We also analyzed the flavonoid compounds found in the different organs of common tartary buckwheat and rice-tartary buckwheat. Even though the content of rutin was similar in both the cultivars, the distribution of the 3 main flavonoids—rutin, quercetin, and kaempferol—was different in the 2 cultivars, both across organs and within the seed. These results indicate that in the 2 tartary buckwheat cultivars, flavonoid biosynthesis is carried out by different mechanisms. [Copyright &y& Elsevier]