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Title: RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY PARAMETERS OF COOKED SWEETPOTATO TEXTURE

Author
item TRUONG, VAN - NCSU
item Walter Jr, William
item HAMANN, D - NCSU

Submitted to: Journal of Texture Studies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Texture is an important attribute of foods and is an essential factor in consumer perception of food quality. Cooked sweetpotatoes have been arbitrarily classified into "moist" or "yam" types, having soft, syrupy texture, and "dry" types, having a firm, mealy texture. However, objective determination of the textural properties using modern instrumental methods has not been conducted, nor have instrumental parameters been compared with sensory data. To accomplish this, we performed a fundamental test (uniaxial compression), an imitative test (Texture Profile Analysis) and a sensory texture profile analysis on ten sweetpotato selections, which represented both types, as well as some which had textural properties intermediate between the two. We found that several instrumental parameters were strongly related to two types of sensory responses and that some fundamental and imitative parameters were also highly related. This research has provided objective instrumental measures of sweetpotato texture and has demonstrated that some instrumental parameters can be used to predict sensory characteristics of cooked sweetpotatoes.

Technical Abstract: This study compared two instrumental methods, namely uniaxial compression and texture profile analysis (TPA), with sensory evaluation in describing the textural properties of cooked sweetpotatoes. The steamed cooked samples (1.4 x 2.2 cm cylinder) of four cultivars and six selections were subjected to a trained texture profile panel for sensory ratings and the two instrumental methods for determination of the mechanical properties. Factor analysis indicated that the 15 sensory variables were grouped into 3 main factors, namely moistness-firmness (factor 1), particles (factor 2), and fiber (factor 3). Among the instrumental parameters, shear stress of compression and fracturability, hardness, and gumminess of TPA correlated highly (r = 0.73-0.95) with both the mouthfeel and mechanical-type sensory notes. These parameters of the two instrumental methods were linearly related (R square = 0.95) and could be converted from one to another with a high degree of reliability. Regression equations based on shear stress significantly explained (R square = 0.71-0.91) eight of the sensory notes. These instrumental parameters can be good predictors of cooked sweetpotato texture.