Biochemical Composition and Glucose Syrup Production Potential of Elite Yam Varieties from Benue State, Nigeria

The starchy tubers of five elite white yam (Dioscorea rotundata) varieties (Okpani, Hemba, Ogoja, Dorban and Ameh) from Benue State (North – Central, Nigeria) were biochemically assessed as possible raw materials for the production of glucose syrup and yam flour. Glucoamylase enzyme was used in profiling the rate of glucose production. The glucose production was monitored using the glucose oxidase method. Standard phytochemical methods were used to determine the proximate composition and mineral content of the samples. Results showed that the gelatinized starch slurry of Okpani variety gave the highest rate of glucose syrup production (60%) at 24 hours reaction time followed equally by those of Hemba and Ameh (55%) respectively. The five elite yam varieties had a pre-processing proximate composition of 3.01 – 3.81% protein, 0.81 – 1.03% fat, 1.46 – 1.74% crude fibre, 1.29 – 1.31% ash and 47.41 – 48.78% moisture. The calculated caloric values and total carbohydrate were (198.15 – 203.62 Cal/100g) and (43.99 – 45.13%). The mineral analyses showed that the yam varieties had appreciable values for mineral elements such as 0.36 – 0.57mg/100g phosphorus, 0.30 – 0.70mg/100g potassium, 0.07 – 1.20mg/100g calcium, 0.38 – 0.47mg/100g magnesium, 0.02 – 0.05mg/100g iron, 0.05 – 0.07mg/100g sodium and 0.01 – 0.03mg/100g zinc. The futuristic potentials of the obtained values were discussed in the paper.