Stability of anthocyanins from agro-industrial residue of isabel grape grown in São Francisco Valley, Brazil

Abstract

Grape by-products are promising and sustainable sources of anthocyanins. Considering the factors related to degradation of those pigments, spectrophotometric and kinetic analyzes were carried out with the aim to evaluate the light and heat stability of anthocyanins from Isabel grape residue. We found that the exposure to luminosity (80W; 2500 lux) and high temperature (≥ 70ºC) significantly affected the absorption and content of those compounds (p <0.05), whose the most stable condition was obtained at 50°C (t1/2: 37.7h; k: 1.84 x 10-2 h-1) and protected from light (t1/2: 3,320.6h; k: 2.09 x 10-4 h-1). Therefore, the anthocyanins from the agroindustrial residue of Isabel grape are an alternative of natural colorants for food that can be packaged in opaque packaging and not subjected to severe heat treatment during processing.