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 50% of the total protein intake. Major cultivars of sweet potatoes in the Tari 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 and the Asaro valley contained, respectively, 1.4% and 0.8% of protein in fresh 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 samples and 85 in the Asaro samples, using values of FAO/WHO (1973). Protein content and amino acid scores of sweet potatoes in the Tari basin were higher than those previously reported in Papua New Guinea Highlands probably because of introduction of new cultivars in recent decades, and thus protein intake of the inhabitants may have been increased.