Sensory properties of pre-treated blast-chilled yam (Dioscorea rotundata) as a convenience food product

Abstract

Yam (Dioscorea sp.) is a popular staple tropical root crop in West Africa. Its postharvest loses are between 30 - 40%. Pretreated packaged convenience yam would address postharvest losses of yam. Dioscorea rotundata var. fitaa was pretreated in a factorial design with sodium metabisulphite, water blanch and steam and subsequently blast chilled at hard (-24°C) and maxi chill (-26°C) temperature regimes. A Hedonic scale of 1-9 with twenty trained judges was employed to evaluate the sensory characteristics of fried yam chips (1.0cm2 x 7.0cm sizes) and boiled yam (4.0cm2 x 7.0cm sizes) on appearance, colour, aroma, taste, texture, mouthfeel, overall acceptability and crispness for fried yam chips. Sodium metabisulphite treatment showed the best overall acceptability for both boiled and fried treatments for maxi chilled than hard chilled against all other treatments. Overall acceptability for sodium metabisulphite was in the range of 7.2 - 7.9 with the highest attributes from appearance, taste, aroma and colour. The sensory ranges for water blanch treatments were 6.1 - 6.8 with the highest attributes for taste and aroma. Steam treatment recorded sensory ranges of 6.1 - 7.1, however in combination with sodium metabisulphite the ranges increased to 6.4 - 7.6 with the best sensory attributes for aroma, colour and taste. The sensory attributes indicated a potential for pretreated convenience packaged Dioscorea rotundata var. fitaa