Effect of Processing on Phytochemicals and Nutrient Composition of Tiger Nut (Cyperus esculentus L)

Abstract

The study investigated the effect of processing on phytochemicals and nutrient composition of tiger nut (Cyperus esclentus L). Tiger nut also is known as Earth-almond was purchased as dried tiger nut tubers, carefully selected to remove dust particles and shared into four sets. The first set was further air-dried (EAAd) for four days and blended using laboratory miller. The second, third and fourth sets were soaked in water for four days to rehydrate. After which the following processing methods were applied; blanching at 80°C for 10 minutes (EAB), soaking in water to ferment for 4 days (EAF) and dehydrated (EAD) by oven drying again after rehydration respectively. The 2nd-4th sets were then oven-dried at a temperature of 60°C for 17 hours before milling into flour. Results of proximate analysis of the processed Earth-almond showed EAF to have the highest concentration of protein (8.37 ± 0.12), carbohydrate (49.01 ± 0.17) and ash (6.20 ± 0.12). The highest lipid (7.55 ± 0.06) and crude fibre (19.50 ± 0.23) was recorded for EAD, while the highest moisture content was recorded for EAB (19.71 ± 0.35). EAF, significantly (p<0.05) improved mineral and amino acid contents; while processing generally reduced the phytochemical content when compared with the air-dried sample (EAAd).