Profiling phenolic compounds in underutilized mango peel by-products from cultivars grown in Spanish subtropical climate over maturation course.

Nutraceutical market has undergone an exponential growth worldwide due to its health link-up. With the purpose of evaluating nutraceutical value, the phenolic composition of underutilized mango peel by-products of three cultivars ('Keitt', 'Kent' and 'Osteen') grown in Spanish subtropical climate was monitored at three maturation stages (green, ripe and overripe). Tracking the total phenol content, mango peels were figured out to have until twenty-seven fold higher than edible fraction. Mango peels comprised a wide range of phenolic compounds such as mono- and di-galloyl compounds, gallotannins, phenolic acids, benzophenones and flavonoids. The influence of both factors, cultivar and maturation degree, on the phenolic composition was the main outcome of the research. 'Keitt' mango peel was revealed as the cultivar with the highest phenolic content mainly due to the great quantities of galloyl glucose, 5-galloylquinic acid, digalloylquinic acid, hexagalloyl glucose and macluring galloyl glucoside detected. Regarding to the effect of maturation degree, green mango peels showed the highest amounts of polyphenols, although this behaviour could be dependent on the mango cultivar. Therefore, mango peels resulted to be a promising and low-cost resource of phenolic compounds to be exploited in food industry, but to enhance the nutraceutical value, factors such as cultivar and maturation degree should be taken into account.

HPLC-DAD-Q-ToF-MS profiling of phenolic compounds from mango (Mangifera indica L.) seed kernel of different cultivars and maturation stages as a preliminary approach to determine functional and nutraceutical value.

Mango seed kernel is a by-product which is usually discarded. However, it has been confirmed in this study that seed kernel exhibits more phenolic compounds with bioactive properties than edible fraction of mango. The influence of factors such as cultivar and maturation degree on the phenolic composition has been studied to evaluate nutraceutical value. The comprehensive analysis of phenolic composition by HPLC-DAD-Q-ToF-MS seed kernel from different cultivars ('Keitt', 'Kent'and 'Osteen') at five maturation stages was conducted. Results evidenced that 'Keitt' samples exhibited higher quantities of iriflophenone glucoside, maclurin C-glucoside, maclurin digalloyl glucoside, mangiferin, 5-galloyl quinic acid and trigalloyl glucose at the first three ripening stages. However, seed kernel from 'Osteen' variety showed higher amounts of hexa- and hepta-gallotannins whose concentrations diminished over the maturation course. Therefore, cultivar and maturation stage factors should be take into account due to their influence on the phenolic composition and subsequently on the nutraceutical value.

Pressurized GRAS solvents for the green extraction of phenolic compounds from hibiscus sabdariffa calyces.

An environmental friendly extraction procedure has been tested to extract phenolic compounds from H. sabdariffa calyces using pressurized GRAS solvents. A central composite rotatable design (CCRD) was performed to evaluate the influence of the main operational conditions: temperature (40-200 °C) and solvent composition based on aqueous hidroalcoholic solutions (0-100% ethanol). Phenolic composition of experimental extracts analyzed by HPLC-ESI-QTOF-MS showed that higher temperatures and greater ethanol percentages drove to solvents with lower dielectric constants, which resulted in extracts with major quantities of phenolic compounds. An exception was the extraction of cyanidin-3-sambubioside that could only be quantified in extracts performed at the lowest temperature (40 °C) due to its thermal sensibility. In addition, a RSM was carried out with the aim to maximize the extraction of total phenolic content. To this end, the predicted optimal extraction conditions by RSM were 200 °C and 100% (v/v) of ethanol. Results showed that temperature and ethanol percentage had a significant influence on the extraction of total phenolic compounds (p value < 0.05). The mathematical model pointed out 200 °C of temperature and 100% of ethanol as the optimum conditions to perform the isolation of phenolic compounds by means of pressurized GRAS solvents.

Lipid nanocarriers for the loading of polyphenols - A comprehensive review.

Polyphenols are secondary metabolites found in all vascular plants and constitute a large group of at least 10,000 unique compounds. Particular attention is currently being paid to polyphenols attributed to their beneficial effects in the protection and prevention of several diseases. While their use in food, pharmaceutical and cosmetic industries is largely documented, several environmental conditions (e.g. light, temperature or oxygen) may affect the physicochemical stability of polyphenols, compromising their bioactivity in vivo. To overcome these limitations, the loading of polyphenols into nanoparticles has been proposed aiming at both increasing their bioavailability and reducing eventual side effects. Lipid nanoparticles offer several advantages, namely their biodegradability and low toxicity, with the additional capacity to modify the release profile of loaded drugs. This paper is a review of the recent advances of lipid nanocarriers commonly used for the encapsulation of polyphenols, highlighting their added value to increase bioavailability and bioactivity of this group of compounds as well as their application in several diseases.