PHYSICO-CHEMICAL AND RHEOLOGICAL PROPERTIES OF JUICES OF SOME EXOTIC FRUITS IN AN AGROFORESTRY SYSTEM AT DIFFERENT MATURITY STAGES

Nigerian Journal of Forestry, 49 (2) 127 - 133

Oyerinde, A.S. (2019)

Abstract
Knowledge of the rheological properties of food products is important for design and process evaluation, process control and consumer's acceptability of a product. The physico-chemical and rheological behavior of Orange, Pineapple and Grape juices, some common agroforestry fruit species were studied considering each fruit at four different stages of maturity viz: unripe, fairly ripe, fully ripe and overripe stages, so as to determine the flow behavior they exhibit, the pH level and the amount of sugar concentration present. The results obtained indicated that the apparent viscosity decreases with increase in shear rate for the samples. The viscosity values ranged between 0.0493

– 1.5513 Pas, pH values between 3.12 - 4.17, and the sugar concentration between 4.5 – 18o Brix respectively. The unripe fruit juices of Orange, Pineapple and Grape have pH values of 3.36, 4.17 and 3.12 respectively, which were all acidic. Orange and Grape juice showed pseudoplastic behavior while Pineapple juice at its overripe stage showed a viscoplastic behavior.

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