Abstract: The leaves of Moringa oleifera (periyakulam-1, an improved cultivar) were dried by 6 industrial drying methods: shade drying, sun drying, and mechanical (hot air at 40 and 60 ℃, microwave and far-infrared ray) drying. The major nutritional and functional components, vitamins and amino acid contents in the dried leaves were investigated. The essential amino acid composition was evaluated by score of ratio coefficient of amino acid (SRCAA) according to the World Health Organization/Food and Agriculture Organization of the United Nations (WHO/FAO) reference pattern. The results showed significant differences in the contents of protein, total phenols, vitamin E, β-carotene, vitamin B2, vitamin C, vitamin B6, nicotinic acid and pantothenic acid, while no significant difference in crude fat, flavonoid or polysaccharide contents of Moringa oleifera leaves subjected to different drying methods was observed. On the whole, hot air drying at 60 ℃ had the lowest impact on the nutritional and functional components and amino acids; L, a and b values of the dried leaves were 90.26, 5.55 and 6.35, respectively, the contents of protein, flavonoids, total phenols, total amino acids, essential amino acids, vitamin E, β-carotene, vitamin B2, vitamin B6 and pantothenic acid were 30.76%, 3.17%, 13.82%, 30.56%, 12.35%, 113.00 mg/100 g, 60.36 mg/100 g, 1.90 mg/100 g, 8.18 mg/100 g, and 89.10 mg/100 g, respectively, which were higher than those obtained using other drying methods. The proportion of essential amino acids in total amino acids was 1.17 times higher than the WHO/FAO reference pattern and SRCAA was 63.88. According to the WHO/FAO reference pattern, the first limiting amino acids were methionine and cystine. Overall, hot air drying at 60 ℃ was more suitable for drying of fresh leaves of Moringa oleifera. The results of this study can provide scientific information for industrial exploitation of Moringa oleifera leaves.

Key words: drying methods, Moringa oleifera leaves, chemical components, amino acid composition evaluation