Effect of the use of lipoxygenase-free soybean line on the sensory attributes of soymilk and tofu

Abstract

Flavor is the most important factor limiting consumption of soy foods in western markets. Soybean lines lacking one or several of the lipoxygenase isozymes involved in flavor have recently been developed. Sensory evaluation provides relevant information related to actual perception which presents some challenges that must be addressed. Perception of flavor by people varies according to their background. The use of terminology to describe the sensory attributes must be addressed. Also, the dynamism of the perceived intensity of some sensory attnHtf»s must be considered for evaluation of soy products. In the first part of the present study, three groups of panelists from the United States, Japan and China were trained to describe and compare soymilk or tofli made from lipoxygenasefree and normal soybean lines. Soymilk made from lipoxygenase-free soybeans had less cooked beany aroma, less cooked beany flavor and less astringency. Panelists noted no differences between lipoxygenase-free and normal soybeans for milky flavor, wheat flavor, thickness, chalkiness or aftertaste. Tofli made from lipoxygenase-free soybeans had less cooked beany flavor than that made from normal soybeans. There were no differences in cooked beany aroma, raw beany aroma, raw beany flavor, wheat flavor, astringency, hardness, darkness or yellowness. The second part of the research comprised the description of the concept related to the 'beany' attributes. A panel of five judges was trained to describe and evaluate different soymilks. Descriptors used to describe 'beaniness' were 'raw as hexanal' for flavor or aroma, 'grassy' flavor, and 'sweet as green floral' flavor. Significant differences 0.01) were found among commercial soymilk and soymilks processed from normal or lipoxygenase-free soybean lines and lipoxygenase-free soybeans stored for 1 yr at A°C.