Effects of Pretreatments on the Physicochemical Properties of Deep Fat Fried Plantain Strips

Abstract

Deep-fat frying of plantain strips was investigated with the aim of optimizing the effect of pretreatments with sorbitol and carboxymethyl cellulose to minimize oil uptake. The effect of sorbitol and carboxymethyl cellulose on water retention, oil uptake, crispness, colour and  breaking strength of the plantain strips were evaluated. The experiment was Response surface methodology designed as Face centered central composite design (FCCCD). The levels of sorbitol concentration ranged between 0.5 - 2.5% and carboxymethyl cellulose concentration (CMC) 1 - 3%. The plantain was washed, peeled, sliced and blanched at 850C for 6 minutes. It was immediately immersed in an aqueous solution of CMC mixed with sorbitol, drained and dried at 1000C for 3 minutes. Frying was carried out at 1800C for 4 minutes, cooled and packaged in an air tight polyethylene bag.  The dependent variables : water retention, oil uptake, crispness, colour, breaking strength, free fatty acid,  peroxide value were in the following ranges 3.02 - 4.95 %, 1.21 - 1.93%, 3.95 - 4.95 Nnm-1, 41.65 - 70.33, 11.76 - 18.08 N, 3.53 - 5.08 mg(KOH)/g and 2.07 - 4.01 meq/kg respectively. The optimum values of the dependent variables were 3.95 %, 1.63 %, 4.67 Nnm-1, 17.23 N, 4.23 mg(KOH)/g and 2.87 meq/kg at the concentrations of 1.75 % sorbitol and 1 % CMC with a frying temperature of 1800C for 4 minutes. Therefore, pretreatment had a significant effect (p<0.05) on the quality attributes of the deep fat fried plantain strips.