Résumé
Plantains and bananas are one of the major staple foods of sub-Saharan Africa and Latin-America. These fruit are source of dietary minerals and vitamins. Deep-fat frying unit operation is widely used for the transformation of plantain in Latin-America and in Africa. The aim of this research was to evaluate the influence of deep-fat frying on the micronutrients of plantain (Musa AAB "barraganete"). Influence of the raw material (two batches) was analyzed. Cylinders (diameter 30 mm, thickness 10 mm) of plantain were fried at four thermal treatments (120-180° C and from 24 to 4 min). Molecules of nutritional interest with water soluble properties (potassium, L-ascorbic acid) or lipid soluble properties (alpha-carotene, beta-carotene) were quantified during the course of frying. One plantain batch was initially rich in L-ascorbic acid (24.4 ± 0.9 mg/100mg) and poor in total carotenoid (0.6 ± 0.3 mg/100mg), while the other was poor in L-ascorbic acid (7.5 ± 0.3 mg/100mg) and rich in total carotenoid (2.1 ± 0,7 mg/100mg). On line measurements of the water content and internal temperature profile allow to characterize the behaviour of bath products during deep-fat frying. The thermal study used the cook value as indicators of the effect of thermal history on quality. Potassium was determinate by ICP; L-ascorbic acid and carotenoid determinations were performed by HPLC. Deep-fat frying had no significant effect on potassium contents at any frying- conditions. Exclusively with the plantain initially rich in L-ascorbic acid, a-carotene and ,alpha-carotene, significant losses were observed. The average loss on L-ascorbic acid. alpha-carotene and beta-carotene were close to 75%, 44% and 35%, respectively. Cook values were very different at any frying conditions, while the lasses of micronutrient were not significantly different at the four frying treatments. Cook value parameters does not seem relevant. These couldn't be explained just with a first order kinetic thermal degradation behaviour. Perhaps, the heterogeneous distribution of micronutrient across the plantain (in radial direction) and/or cellular scale could explain of such behaviours. However it's difficult to develop more extensive assumptions without histological information of the micronutrient localization in plantain. (Texte intégral)