Effect of various drying methods on the physical characteristics of purple yam powder

Abstract

Purple yam (Dioscorea alata) is a type of plant that grown in almost all regions of Southeast Asia. In Indonesia, purple yam is one of the most popular types of sweet potatoes compared to other types of the genus Dioscorea. Purple yum is usually consumed directly as a side dish, or processed into a powder. One important process of making purple yam powder is drying. In this study, the characteristics of purple yam powder were evaluated from several drying methods, namely sunlight drying (SD), cabinet drying (CD), and pneumatic drying (PD). The pneumatic dryer used was self-made with a stainless steel plate (3 mm thickness) and has total dimension of 1600x 500x 2500 mm. The results showed that the CD sample had the lowest water content. The purple yam powder by CD and PD can produce brighter powder compared to that with SD method. From the FM test, the smallest FM value was obtained from CD sample. CD sample proven to be able to retain purple yam nutritive values after drying process.