Comparison of selected underutilized yam flours for their proximate and phytochemical composition

Abstract

With the urbanization and changing food habits, most of these underutilized yams have lost their significance. However, the study of their nutritional value is insufficient. The overall objective of this study was to evaluate the nutritional composition, functional properties and phytochemical composition of four selected underutilized yam varieties in Sri Lanka; “Dioscorea alata”, “Amorphophallus campanulatus”, “Canna indica” and “Dioscorea pentaphylla”. The moisture content of “Dioscorea alata” was the highest (7.75 ± 0.09%) and the lowest was recorded in “Canna indica” (6.41 ± 0.04%). All five varieties were low in fat content and highest was recorded in “Dioscorea alata” (1.09 ± 0.01%). The crude protein content of “Dioscorea alata” and “Amorphophallus campanulatus” were 4.28 ± 0.13%, 5.70 ± 0.11% respectively. The highest ash content was recorded in “Amorphophallus campanulatus” (4.711 ± 0.36%). All five yam flour varieties were high in carbohydrate content and highest was recorded in “Canna indica” (85.28 ± 0.96 %). The observed fiber content in “Dioscorea pentaphylla” (5.20 ± 1.08 %) was much higher than the reported value of other yam flour varieties. K was the most predominat element found in each yam flour varieties. The highest K content was recorded in “Amorphophallus campanulatus”. In antioxidant screening of “Canna indica”, by using DPPH Radical scavenging activity, showed highest value compared to other varieties. The highest TPC of 42.50 ± 0.98 mg Gallic acid equivalent per g was recorded in “Canna indica” and the lowest was recorded as 6.47 ± 0.01 mg Gallic acid equivalent per g in “Dioscorea pentaphylla”. Functional properties of the five varieties were illustrated by the water holding capacity and oil holding capacity. The highest oil holding capacity and the highest water holding capacity were recorded in “Amorphophallus campanulatus” (WHC-243.08 ± 2.56% & OHC-77.04 ± 2.95%).