Storage proteins in cassava and sweet potato root tissues, quality and effects of processing and other compounds.

摘要

Cassava is a staple food in Africa with deficiency in protein content. Evaluation of protein fortified cassava was studied. Sporamin, the major protein of sweet potato, has potential for cassava fortification. One objective of this study was to evaluate effects on sporamin due to different parameters involved in cassava physiological postharvest deterioration (PPD). Model systems were designed to determine sporamin modification. Sporamin did not suffer any major degradation by PPD components: scopoletin (a hydroxycoumarin), cassava phenolic extract, peroxidase and hydrogen peroxide. Oxidation of methionine was observed at 0 and 24 h incubation with or without oxidation factors by matrix-assisted laser desorption/ionization (MALDI). Polymerization of sporamin A and B was observed by presence of a high molecular weight band in SDS-PAGE.;Physico-chemical parameters for cassava flours with zeolin, sporazein, sporazein plus pro-vitamin A and pro-vitamin A, and a wild type sample were measured. Wild type flour had the greatest pasting temperature (90.4 °C) while pro-vitamin A fortified flour had the greatest final viscosity (269.94 RVU).;Fufu, a fermented cassava product, was prepared from flour with and without Lactobacillus plantarum 6710 starter for 96 h while monitoring lactic acid bacteria. Physico-chemical parameters of the intermediate uncooked products (wet fufu and fufu flour) were evaluated. Use of Lactobacillus plantarum allowed a rapid acidification of wet fufu reaching maximum acidity at 72 h. Thus, the use of starter cultures lead to a rapid acidification of the product inhibiting the growth of spoilage and pathogenic bacteria.;In general, fermentation caused a significant decrease of the protein content in the fortified samples.;Sensory evaluation of cooked fufu by a trained panel showed a significant influence of flour source in most attributes evaluated: brown color intensity, stale and fermented aromas; and hardness, adhesiveness and springiness (p≤0.05). However, no significant differences in the “fufu” aroma descriptor were found. Similar volatile compounds were identified in all cooked fufu samples.;Sporamin should be considered for protein fortification of cassava without expecting a major damage to the protein due to PPD. Based on “fufu” aroma sensory evaluation, fortified cassava flours offer consumers a product similar to that commonly consumed.