NUTRITIONAL AND ANTINUTRITIONAL ASSESSMENT OF SOME UNDERUTILIZED CORMS, RHIZOMES AND TUBERS

Abstract

Background. With ever-increasing populace pressure and rapid depletion of natural resources, it has become exceptionally important to diversify the present time agriculture with the cultivation of some wild varieties of tubers, rhizomes and corms in order to meet various human nutrient needs. However, information regarding the nutritional and antinutritional composition is meager. Objective. To study the chemical composition and antinutritional factors of the wild edible corms, rhizomes and tubers consumed by the Palliyars and Kanikkar tribes living in South Eastern Slopes of Western Ghats, Tamil Nadu Methodology. The wild edible corms of Alocasia macrorrhiza, Amorphophallus paeoniifolius var campanulatus, Amorphophallus sylvaticus, Colocasia esculenta, Xanthosoma sagittifolium, Xanthosoma violaceum, rhizomes of Canna indica, Maranta arundinacea and tubers of Asparagus racemosus, Nymphaea pubescens and Nymphaea rubra were analysed for proximate and mineral composition, starch, vitamins like niacin, ascorbic acid and antinutritional factors like total free phenolics, tannins, hydrogen cyanide, total oxalate, amylase and trypsin inhibitor activities were quantified. Also, in vitro protein and starch digestibility were assessed. Results. The rhizome of Maranta arundinacea and tubers of Nymphaea pubescens contain high quantity of crude proteins. The tubers of Asparagus racemosus contained higher amount of crude lipids. The corms of Alocasia macrorrhiza, Colocasia esculenta, Xanthosoma sagittifolium and Xanthosoma violaceum appeared to have a higher level of potassium content compared to recommended Dietary allowances (RDA) for infants, children and adults. The corms of Alocasia macrorrhiza, Amorphophallus sylvaticus, Xanthosoma violaceum and rhizomes of Maranta arundinacea were found to contain more starch. All the investigated samples had low in vitro protein digestibility. Implications. The present result highlights the potentiality of these underground plant parts as source of unconventional foods. Being wild, they also are easily accessible and cheaper. Studies on nutritional value of wild plant food are of extensive importance since it may help to recognize long forgotten food resources. Conclusion. Most of the wild edible corms, rhizomes and tubers were found to be a good source of protein, lipid, total dietary fiber, starch, vitamins and minerals. All the investigated samples exhibited variations in the levels of the total free phenolics, tannins, hydrogen cyanide, total oxalate, amylase and trypsin inhibitors