Sorption, texture, and colour properties of edible films elaborated with cassava starch, rebaudioside A, and yerba mate extract

BEUTER, D. A.; LA CAVA, E. L.; HOLOWATY, S. A.; MEZA, B. E.; BRUMOVSKY, L. A.; PERALTA, J. M.

Buenos Aires

Congreso; 11th World Congress of Chemical Engineering; 2023

Asociación Argentina de Ingenieros Químicos

Edible films are used in the food industry as covers, wraps or separation layers to enhance product quality, stability, and safety. They are selective barriers to moisture transfer and can increase the performance of foods by the inclusion of natural bioactive compounds and colouring agents. The use of plasticisers is necessary to decrease the film brittleness, preventing its destruction during handling and storage. The objective of this work was to study the water adsorption isotherms, texture profiles, and colour of edible films elaborated with native cassava starch (film matrix material), rebaudioside A (bioactive compound), glycerol (plasticiser), and different concentrations (0, 0.5, 2, and 4% w/w) of yerba mate extract (YME) powder (colouring and alternative plasticiser agent). Formulations were elaborated following a procedure previously published [1]. Drying was carried out by a casting method at 50, 60, and 70°C for 24 h. Films were stored in hermetic plastic bags at 25°C for further analysis. Water adsorption isotherms were obtained by placing dried (at 60°C) film samples in hermetic sealed glass jars containing saturated salt solutions with water activities from 0.113 to 0.836. The jars were stored at 30°C for four weeks. The equilibrium moisture content (M) of films was measured gravimetrically in quadruplicate (dry basis). Texture profiles were obtained through penetrometry (six replicates). Values of displacement at failure point (D), maximal force at failure point (F), and mechanical work associated with F (W) were determined from the force/displacement curves. Film colour was measured using the Cielab scale to determine, in quintuplicate, the lightness (L), redness (+a)/greenness (-a), and yellowness (+b)/blueness (-b). Statistical analysis was carried out using ANOVA and the Tukey's range test. As result, water absorption isotherms showed a type II form and the M values decreased as the YME concentration increased. Texture profiles displayed an increase in D as the YME content and drying temperature increased. For films dried at 70°C, values of F and W decreased as the YME concentration increased. For lower temperatures, films with 2% (w/w) of YME showed the higher values of F and W. Colour parameters indicated that, as the YME content increased, the values of a increased and L decreased. Also, values of b for films with 0.5, 2, and 4% w/w of YME were similar but higher than control samples. In all cases, the effect of the drying temperature on a, b, and L was not significant. As conclusion, concentrations lower than 5% w/w of YME might affect the water adsorption behaviour, texture, and colour of cassava starch-based edible films enriched with rebaudioside A. These findings are useful in designing new functional films for food preservation purposes.References1. Beuter, D. A., Meza, B. E., Brumovsky, L. A., Peralta, J. M. (2022). Effect of yerba mate (Ilex paraguariensis St. Hil.) extract on thedrying behaviour of cassava starch films enriched with rebaudioside A. Journal of Food Processing and Preservation. In Press, DOI:10.1111/jfpp.17159