Evaluation Of Some Nutritional, Physicochemical And Phytochemical Parameters Of Dioscorea Rotundata (White Yam) Flesh And Peels Exposed To Four Different Storage Patterns In Nigeria.

ABSTRACT

The hue and cry of food insecurity in Nigeria prompted the curiosity of this study. This study investigates the evaluation of some nutritional, physicochemical and phytochemical parameters on Dioscorea rotundata (white yam) flesh and peels exposed to four different storage patterns in Nigeria. Four storage patterns and 20 tubers of yam were used for this study. The yams were grouped into the four storage patterns: Open Sided, Yam Barn, Heap on Floor and Platform Storage, and the analysis was carried out for four weeks on a weekly basis. The storage was done outdoor. The carbohydrate content in the yams increased generally in the second week, before variations occurred between yams exposed to different storage patterns. The highest carbohydrate content was observed in the yam flesh exposed to the Platform storage, in the fourth week, (36.5g/100g). The highest in the yam peels was observed both in the second week of Yam Barn storage and fourth week of Platform storage (9.8g/100g). Carbohydrate content throughout the analysis varied from 0.6 to 36.5g/100g. Protein content varied among yams exposed to different storage patterns. The highest protein content was 26.6g/100g, observed in the yam peels of Platform storage, in the third week. Protein content in the yam flesh and peels varied from 0.3 to 26.6g/100g. Moisture and ash content in the yam flesh and peels decreased throughout the storage period. Moisture content in the yam flesh and peels were similar. Moisture reduced in the yam flesh and peels from 64% to 55% and 69% to 64% respectively. Ash content was higher in the yam peels than the flesh throughout. The ash content in the yam flesh and peels reduced from 1.057% to 0.862% and 9.307% to 8.727% respectively. The pH of the yam flesh and peels varied from 5.6 to 6.7 within the four weeks of storage. The lowest pH was for the yam flesh, in the first week of storage. The highest pH is recorded in the Yam Barn Storage, in the fourth week of storage. The variation in the proximate and physicochemical parameters can be as a result of respiration. Some phytochemicals: Alkaloids, Saponins and Steroids tested positive, while Flavonoids, Tannins and Anthraquinones tested negative. It was observed that the storage patterns had no effect on the presence/absence of phytochemicals. It is concluded from the result that the Platform storage pattern is the best to preserve the nutritional content of yams.