Évaluation des caractéristiques fonctionnelles et rhéologiques des farines d'igname pilée instantanées (Dioscorea rotundata) obtenues à partir des tubercules des cultivars utilisés comme parents dans un programme de sélection au Bénin

Abstract

Assessment of the functional and rheological characteristics of instant pounded yam (Dioscorea rotundata) flour obtained from the tubers of cultivars used as parents in a breeding program in Benin Description of the subject. In West Africa, yam tubers are mainly consumed in the pounded form. However, in view of the high perishability of fresh tubers, the consumption of pounded yam throughout the year is becoming a major concern. The transformation of tubers into stable products, such as instant flour that can give a dough with characteristics similar to that of pounded yam, has become a priority. Objectives. To evaluate the functional and rheological properties of instant pounded yam flour (InstAgoun) produced from 48 cultivars used as parents in a selection program on yams in Benin. Method. The flours from the 48 yam cultivars were characterized in terms of their color and their functional and rheological properties, using standardized methods. Results. The results showed that the flour yield (14.7 – 27.9%), color (L*: 70.1 – 83.9; a*: -1.2 – 1.6; b*: 0.8 – 13.6), solubility (6.4 – 11.9%), peak viscosity (1,048 – 4,376 cPs), final viscosity (1,568 – 6,251 cPs), holding strength viscosity (875 – 4,004 cPs), viscosity breakdown (14 – 592 cPs), viscosity setback (395 – 2,418 cPs), peak time (5 – 8 min) and the starch pasting temperature (73 – 93 °C) of the flours produced varied significantly depending on the yam cultivars. However, no significant difference was observed in the swelling power of the flours derived from the different cultivars, which varied from 3.2 to 5.1 g·g-1. In terms of functional and rheological characteristics, eight promising cultivars (Singor, Parayobou, Agbaobé, Portchahabim, Tarayè, Tchée, Anklouman, and Kpagninan) were identified as the most suitable for producing instant pounded yam flour. Conclusions. An effective introduction of these eight promising cultivars into breeding programs could generate varieties that will meet the quality requirements of the various program participants for the improvement of the yam value chain in the Republic of Benin.

Keywords

• flour yield
• luminance
• pasting properties
• solubility index
• swelling power