Extrato de repolho roxo como indicador de qualidade em filmes para aplicação em alimentos.

Abstract

With the development of the food industry, the role of packaging has been reinvented beyond its function of containing and protecting the product, but also with the idea of informing the consumer in real time about the quality of the product through the intelligent packaging. In this context, the objective was to develop and characterize food quality indicator films using green banana starch alone or combined with other biopolymers incorporated with vegetable extract of purple cabbage as a colorimetric indicator. The films developed were submitted to the following treatments: (i) banana starch with indicator; (ii) banana starch and gelatin with indicator; (iii) alginate, banana starch and gelatin with indicator; (iv) banana starch without indicator; (v) banana starch and gelatin without indicator; (vi) alginate, banana starch and gelatin without indicator. The extract of purple cabbage was evaluated for sensitivity to light, and the films were submitted to swelling tests, water vapor transmission rate, sensitivity evaluation to different pH ranges and activation test in sheep meat. The light influenced the stability of the purple cabbage extract, with a reduction of 10.96% in the rate of phenolic compounds. In the index of swelling, the films with indicators presented a lower water absorption rate when compared to the films without indicators. In the evaluation of the permeability to water vapor, the starch film without indicator had lower permeation rate (1,05 g.h־1.mm.m2.Pa־1), while the alginate/starch/gelatin indicator film showed a higher permeation rate (5,13 g.h־1.mm.m2.Pa־1). The activation of the indicator films in the acid, neutral and alkaline solutions showed a rapid color change and it remained stable. The films with indicators in contact with the ovine meat presented a color change through the colorimetric parameters for both films with indicators during the seven days of refrigerated storage, where only the alginate/starch/gelatin film with indicator showed a noticeable color change ( ΔE = 8.10) to the human eye. The results indicate that the use of natural polymers and vegetable extract in the development of indicator packages are feasible as a vehicle of communication with the consumer, and an economical and environmentally correct alternative.