Associations of Soybean Seed Quality Attributes with Sensory Properties of Natto.

Natto is a popular fermented soybean food product in Japan. Natto quality is partially determined by physical and chemical attributes such as seed size, hardness, water absorption, sugar, calcium, protein, and oil content. However, sensory evaluation following fermentation is critical for selecting genotypes that are suitable for the natto market.  The objective of this study was to determine seed quality attributes that contribute to the taste, flavor, texture, and shelf life of natto. Thirty small-seeded soybean lines were grown at Stuttgart and Rohwer, AR in 2007.  Harvested seeds were evaluated for physical and chemical properties, and natto was produced from each line for sensory evaluation.  The results of sensory evaluation showed that natto samples made from ARK1, SS-516, R05-1953, R05-1989, R05-2505, and R05-2734 were most acceptable at two locations in terms of flavor and texture.  Those lines tend to have softer seed, higher water uptake, lower calcium and protein content.  Natto stickiness was positively correlated with sucrose and total sugar content; natto taste was positively correlated with sucrose content.  Natto hardness was negatively correlated with protein, and protein plus oil content.  Seed protein and hardness were negatively correlated with natto texture.  There was a negative correlation between water absorption capacity and natto shelf life.  The results of this study should facilitate soybean breeding schemes in development of superior natto varieties.