Protein content and amino acid scores of sweet potatoes in Papua New Guinea highlands

Protein content and amino acid scores of sweet potatoes were determined in Papua New Guinea Highlands where sweet potatoes contributed approximately 5 0% of the total protein intake. Major cultivars of sweet potatoes in the Ta ri basin and the Asaro valley, 15 in total, were sampled and their nitrogen and amino acid contents were analyzed. Sweet potatoes in the Tari basin an d the Asaro valley contained, respectively, 1.4% and 0.8% of protein in fre sh weight basis. The concentration was 1.7 times higher in the former than in the latter (t-test,p<.01). The first limiting amino acid was leucine in the samples from both areas and amino acid scores were 87 in the Tari sampl es and 85 in the Asaro samples, using values of FAO/WHO (1973). Protein con tent and amino acid scores of sweet potatoes in the Tari basin were higher than those previously reported in Papua New Guinea Highlands probably becau se of introduction of new cultivars in recent decades, and thus protein int ake of the inhabitants may have been increased.