From mango by-product to food packaging: Pectin-phenolic antioxidant films from mango peels.

The objective of the study was to prepare active films based on pectin and polyphenol-rich extracts from Tommy Atkins mango peels. Aqueous and methanolic extracts showed a variety of phenolic compounds that were identified by UPLC-MS analysis, and a high content of total phenolics that were quantified by the Folin-Ciocalteau method. The methanolic extract showed better results in antioxidant tests and was more effective in inhibiting the growth of Gram-positive and Gram-negative bacteria. The pectin extracted from mango peels showed good thermal stability and a degree of methoxylation of 58.3% by 1H NMR. The films containing the phenolic extracts showed lower water vapor permeability when compared to the control film (without any phenolic extracts). The incorporation of the extracts led to an increase in elongation (ε) and a decrease in tensile strength (σ) and modulus of elasticity (Y). The films with aqueous or methanolic extracts showed higher antioxidant activity in terms of inhibition of the DPPH radical. Therefore, the films developed in this work are presented as a promising alternative for food packaging and/or coating applications.

Antioxidant films and coatings based on starch and phenolics from Spondias purpurea L.

The objective of this study was to prepare, for the first time, active films and coatings from fruit starch (SPFS) and phenolic stem bark extract (SBPE) from Spondias purpurea L. Starch film formulations were prepared with different SBPE contents (5-20 wt% on starch), then cast and dried into films. SBPE showed higher antioxidant activity and antimicrobial activity against both Gram-negative and Gram-positive bacteria. Chemical, morphological, thermal, optical, mechanical, and barrier properties were studied for SPFS-SBPE films. In general, the phenolic extract caused significant changes in starch films (especially when in excess), such as gradual reduction of elastic modulus and tensile strength, increased elongation, opacity, and thermal properties (e.g. glass transition and melting enthalpy). On the other hand, SBPE provided the films with active properties (antioxidant and UV-absorbing). Coatings were applied to minimally processed mangoes (MPM), which were stored for 10 days at 12 °C. SBPE-containing coatings provided better protective action, reducing the total color difference (∆E⁎) and delaying the browning index (BI) during storage as well as reducing fungus attack. The active SPFS-SBPE films showed great potential as environmentally friendly active films and coatings.

In vitro bioaccessibility of copper, iron, zinc and antioxidant compounds of whole cashew apple juice and cashew apple fibre (Anacardium occidentale L.) following simulated gastro-intestinal digestion.

Considering the lack of research studies about nutrients' bioaccessibility in cashew apple, in this study the whole cashew apple juice and the cashew apple fibre were submitted to simulated in vitro gastrointestinal digestion. The samples were analysed before and after digestion and had their copper, iron, zinc, ascorbic acid, total extractable phenols and total antioxidant activity assessed. As a result, for the whole cashew apple juice, the content of copper and iron minerals bioaccessible fraction were 15% and 11.5% and for zinc this level was 3.7%. Regarding the cashew apple fibre, the bioaccessible fraction for these minerals was lower than 5%. The ascorbic acid, total extractable polyphenols and total antioxidant activity bioaccessible fraction for whole cashew apple juice showed bioaccessibility percentages of 26.2%, 39% and 27%, respectively, while for the cashew apple fibre, low bioaccessibles levels were found. The bioacessible percentage of zinc, ascorbic acid and total extractable polyphenols were higher in cashew apple juice than cashew apple fibre.