Effect of genotype,maturity stage and post‐harvest storage on phenolic compounds,carotenoid content and antioxidant capacity,of Andean mashua tubers (Tropaeolum tuberosum Ruiz & Pavón)

The total phenolics, anthocyanins, flavan 3‐ols, carotenoids and antioxidant capacity of mashua (Tropaeolum tuberosum Ruiz & Pavón) tubers from 10 yellow and purple cultivars were determined at different maturity stages (5–7.5 months after planting) and sunning post‐harvest storage periods (7–35 days). Both the antioxidant capacity (ORAC and ABTS assays) and the content of the bioactive compounds tested varied markedly between cultivars. Purple varieties reached the highest antioxidant capacity during tuber development (271–446 µmol Trolox equiv g^?1 DM, ORAC assay). The kinetics of accumulation or disappearance of the bioactive compounds tested during maturation was dependent both on the cultivar and on the compound considered. For anthocyanins, there was a marked increase during maturation in all the purple cultivars. During the sunning post‐harvest storage, the changes in antioxidant capacity (ABTS assay) and content of the bioactive compounds tested also varied between cultivars. A marked decrease in anthocyanins was observed for the anthocyanin‐containing cultivars. In general, the correlation between antioxidant capacity and the content of bioactive compounds varied markedly between cultivars. Antioxidant capacity in purple varieties correlated with total phenolics or flavan 3‐ols while only in some yellow varieties antioxidant capacity correlated with total phenolics. Copyright © 2007 Society of Chemical Industry     

Preparation and physicochemical properties of edible films from gelatin and Andean potato (Solanum tuberosum Group Phureja) starch

A novel edible film formulation using native Andean potato starch (APS) and gelatin (G) was developed, and evaluated as a function of the APS/G ratio (3:1, 1:1, and 1:3). The films were physicochemically, structurally (FTIR and Raman), morphologically (SEM), thermally (DSC/TGA) and mechanically characterised. The addition of starch increased water resistance, clarity and thermal stability of the films. The SEM micrographs showed a heterogeneous surface and a compact structure. The films also showed low values for both tensile strength and elastic modulus. FTIR analysis revealed intermolecular interactions between the gelatin and starch. Edible film obtained in this work may have potential applications in many fields.