Relationship between Storage Quality and Functionality of Common Buckwheat (Fagopyrum esculentum Moench) and Tartary Buckwheat (Fagopyrum tataricum Gaertn) at Different Temperatures

Buckwheat and other grains have become influential in sustainable agriculture and food security owing to climate change. However, subpar storage conditions can result in the deterioration of the nutritional value and active components of buckwheat, making storage quality a significant research subject. This study examined common buckwheat (CB) and Tartary buckwheat (TB) stored at 4 °C, 30 °C, and 55 °C from 0 to 6 months to assess storage quality and its relationship to the preservation of active components. The results of agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) showed that as storage temperature and time increased, both CB and TB exhibited the following differences: significant alterations in color due to an increase in browning index (B.I.), higher acidity from accelerated acid production at high temperatures, and a decrease in total phenolics, flavonoid content, and antioxidant capacity due to thermal degradation of functional components. In the storage quality assessment, no alteration in microstructure or degradation in components was detected after exposure to all times and temperatures, and the content of the primary bioactive compound, rutin, was CB (16.57–27.81 mg/100 g d.w.) and TB (707.70–787.58 mg/100 g d.w.), demonstrating buckwheat’s resistance to microbial contamination. Storage temperature significantly impacts buckwheat’s quality and bioactive components, making it an important element in establishing a sustainable food supply chain.