Water Vapor Permeability and mechanical properties of edible films on native starch from improved cassava variety in Côte d’Ivoire

Résumé fourni par la source

A study in Côte d'Ivoire entitled "artisanal and industrial valorization of native cassava (Manihot esculenta Crantz) and yam (Dioscorea sp)" starches showed that the film produced with starch cassava and vegetable oil showed the most promising coatings capabilities. This film was designed without plasticizer and showed mechanical limits. So, the presence of plasticizer could overcome the fragility of the film, with a commonly used slurry of 15-40/g of glycerol in 100 g of starch. The properties of starch films can be further improved by producing composite films with incorporation of functional additives. Thus, in this present study, starch-based films have been strengthened with addition of a plasticizer (glycerol), an emulsifier (soy lecithin) and a preservative (potassium sorbate). Films were prepared with 5 % oil, 25 and 30 % glycerol, 0 and 5 % soy lecithin and 0.2 g potassium sorbate. Mechanical (Tensile strength and Elongation at break) and water vapor properties of native cassava starch improved variety Olekanga films were determined. Increasing glycerol concentration and soy lecithin addition had no significant effect on water vapor permeability of all films. In opposite significant difference (p <0.05) of glycerol concentration was observed on tensile strength and elongation at break of films. Which was not the case when soy lecithin concentration is increased from 0 to 5 %. Tensile strength decreased with increase in glycerol concentration. Opposite behavior was observed for elongation at break. Films on native starch from improved cassava variety Olekanga in Côte d’Ivoire were less resistant, very elongable with acceptable water vapor permeability.

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