Effect of Indigenous Processing by Obu Manuvu on the Anti-nutrient and Nutrient Factors of Taro (Colocasia esculenta)

Abstract

Anti-nutrient factors are secondary plant metabolites that can adversely affect the full utilization of nutrients in plant-based food products. However, the level of these antinutrients can be reduced by the application of various food processing methods. This study determined the effect of indigenous processing by the Obu Manuvu in Sitio Ladian, Marilog District, Davao City, Philippines on the anti-nutrient factors, proximate composition and mineral content of taro. The indigenous process involves soaking and boiling of taro, which is then stuffed in bamboo tubes to make ‘linutlut na gabi.’ The anti-nutrients analyzed in this study were tannin, cyanogenic glycoside and oxalate. Results showed a significant reduction amounting to 66.67, 98.08 and 91.74% for these anti-nutrients, respectively. The indigenous processing also showed a significant effect on the proximate composition of taro, specifically on the moisture (13.06% increase) and crude ash (2.45% increase) contents. For crude fat, crude fiber and crude protein contents, no significant changes were observed. For the mineral analyses, it was found that iron and manganese increased by 152.45 and 26.32%, respectively, after indigenous processing. Moreover, no significant changes were observed in the zinc and calcium contents of taro after indigenous processing. Hence, the processing method of the Obu Manuvu was effective in decreasing the anti-nutrient content, particularly tannin, cyanogenic glycoside and oxalate. This also improved the nutrient profile of taro as shown by the increase in iron and manganese. This study could be used for future dietary interventions to address issues of malnutrition and food safety.