Methods to routinely predict the texture quality of potatoes by tuber specific gravity

Abstract

Information on texture of steam-cooked potato is of increased importance for consumers of fresh potatoes. As potato texture not only depends on genetic disposition but also on growth conditions, simple and reliable methods are needed to improve characterization of single potato lots. In the present study 65 potato lots were fractionized to 192 tuber samples according to their specific gravity and used for sensory evaluations. The aim was: (1) to further clarify the role of tuber specific gravity, variety and growth condition for texture attributes; and (2) to develop statistical models to predict potato texture objectively and reliably. Texture attributes varied considerably within varieties. The attributes mealiness, dryness, graininess were closely interrelated. Within the varieties, the three attributes as well as sloughing correlated with specific gravity (r = 0.78-0.96). Thus, they were predicted by specific gravity using variety-dependent models. Alternatively, using variety-independent models mealiness was predicted by the two parameters specific gravity and sloughing. Softness was related to the variety, but not to specific gravity. The statistical models may be helpful in optimizing the allocation of individual potato lots to specific cooking types for the retail market and for processing. PRACTICAL APPLICATIONS Information on texture of steam-cooked potato is of increased importance for consumers of fresh potatoes. We were approached by the potato industry to develop simple and reliable methods for characterization of single potato lots in trade. The objective measurement of texture by instrumental methods is rarely performed for routine testing, probably because of the laborious procedures. The measurement of tuber specific gravity is very simple. However, the relationship between specific gravity and various texture attributes is still not clear. We elaborate the relationship in an extensive evaluation using a broad range of potato lots. The models presented here may be applied directly for routine testing. We also suggest adaptations for routine calibration of new varieties and for routine testing of single lots. Further, the study encourages the scale-up of technologies which allow the grading of potatoes according to their specific gravity and thereby increase significantly texture homogeneity. © 2010, Wiley Periodicals, Inc.