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This study investigated the effects of varying proportions of buckwheat flour mixed with wheat flour on the drying characteristics, physical properties, and nutritional quality of instant buckwheat noodle sheets (IBNS). The results indicated that incorporating buckwheat into pure wheat sheets reduced the drying time of IBNS by 10–16.7 min. With the increase in drying time, the amount of free water decreased significantly. The transverse relaxation times (T 2) range gradually decreased, and the overall peak shifted towards the left. During rehydration, sheets with 10% buckwheat content exhibited a rehydration ratio of 17%, which was higher than that of pure wheat sheets. Initially, pure wheat sheets displayed the highest levels of hardness and chewiness during rehydration. The inclusion of buckwheat flour greatly improved the nutritional content and antioxidant capacity of the IBNS. The addition of buckwheat modified the secondary structure of proteins and the ordered structure of starch. Raw sheets with a 10% buckwheat addition demonstrated the highest value of short-range ordered structure (DO) at 2.16. In contrast, noodles with a 30% buckwheat addition showed the highest lacunarity at 38.44 × 10−2. The findings of this study will serve as a theoretical foundation and provide guidance for the production of mixed-grain composite products in the instant food industry. • Adding buckwheat reduced the drying time of IBNS by 10–16.7 min. • IBNS with 10% buckwheat exhibited a rehydration ratio of 17%. • The incorporation of buckwheat promoted the formation of a porous gluten network. • A high content of buckwheat reduced the hardness and chewiness of rehydrated IBNS. • The incorporation of buckwheat increased the antioxidant properties of IBNS. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metabolomics revealed that drying affects flavonoids in sea buckthorn berries. • The flavonoid content increased and antioxidant capacity decreased after drying. • Hot air drying and infrared drying had distinct effects on flavonoid compounds. Flavonoids are major nutrients in sea buckthorn berries. However, the effects of drying methods on flavonoids in sea buckthorn berries are unclear. In this study, ultra-performance liquid chromatography and metabolomics were adopted to analyse the effects of hot air drying (HAD) and infrared drying (IRD) on flavonoid compounds and antioxidant capacity in sea buckthorn berries. In total, 97 metabolites belonging to 12 classes were identified, including 26 flavones, 23 flavonols, and 11 flavanones. Additionally, 32 differential metabolites were identified among groups. Isorhamnetin and quercetin contents increased in response to HAD and IRD, while (-)-epigallocatechin and (-)-gallocatechin contents decreased. Differential metabolism of flavonoid compounds occurred mainly via the flavonoid biosynthesis and secondary metabolite biosynthesis pathways. Flavonoid compound degradation might be associated with antioxidant activity during drying. This study elucidated the effect of drying on nutritional components of sea buckthorn berries and may guide the improvement of quality during food processing. [ABSTRACT FROM AUTHOR]