Phenolic composition and cell-based biological activities of ten coloured potato peels (Solanum tuberosum L.).

The present study provides an in-depth characterisation of the non-anthocyanin and anthocyanin phenolic compounds of potato peels from ten coloured potato varieties. Furthermore, the underexplored bioactive potential (antioxidant, cytotoxic and anti-inflammatory capacities) of the studied peels is comprehensively analysed. Among non-anthocyanin phenolics, caffeic and a caffeoylquinic acid were found in the highest concentrations in all samples, which also showed the presence of O-glycosylated flavonol derivatives and polyamine derivatives. Acylated anthocyanins were identified in red and purple varieties, being pelargonidin, peonidin, and malvidin the most prominent aglycones. All samples revealed antioxidant and antitumor activities, and no toxic effect. The extract of the Rosemary variety presented the best antioxidant and antitumor outcomes and was the only sample to reveal anti-inflammatory activity. These results are valuable for the food-industry by adding value to an important bio-residue, particularly concerning its potential as natural ingredients in novel food and pharmaceutical formulations.

Potato biodiversity: A linear discriminant analysis on the nutritional and physicochemical composition of fifty genotypes.

Fifty potato genotypes from twenty-four different countries of origin, four different flesh colours (yellow, purple, red and marble) and different cultivation types (Andean accessions, landraces, breeder lines and cultivated varieties) were studied in terms of their nutritional and physicochemical characteristics. In general, cultivated varieties and breeder lines showed the highest similarity (slight differences only in some particular fatty acids distributions: C10:0, C12:0 and C22:0) concerning the physicochemical parameters assayed in this work, independently of the geographical origin or tuber flesh colour of these genotypes. Nonetheless, some of the studied landraces and Andean accessions proved to be similar enough to be considered as genotypes with good potential for commercial cultivation. These results can contribute to the supply of new potato genotypes into sustainable farming systems, supporting the protection of potato biodiversity, particularly Andean accessions, landraces and coloured genotypes (red or purple flesh) which are not widely cultivated so far.

Anthocyanin-rich extracts from purple and red potatoes as natural colourants: Bioactive properties, application in a soft drink formulation and sensory analysis.

Aqueous extracts from seven coloured potato varieties (three red-fleshed, three-purple fleshed, and one marble-fleshed) were studied for their anthocyanin content, in vitro biological activities, colouring properties and their potential application in the food industry. Acylated glycosides or pelargonidin and petunidin aglycones were identified as the main anthocyanin forms in the red and purple varieties, respectively. The total anthocyanin content among varieties ranged from 478.3 to 886.2 mg/100 g extract. All the extracts presented in vitro antioxidant, antibacterial and antifungal activities, whereas no toxic effects were detected. Finally, two selected extracts were tested as colourants in a soft drink formulation and presented suitable sensory profiles as well as high colour stability during a 30-day shelf-life when compared with the commercial colourant E163. Therefore, the tested extracts could be used as natural food colourants and considered for substituting the existing synthetic colouring agents.

Nutritional value, physicochemical characterization and bioactive properties of the Brazilian quinoa BRS Piabiru.

Chenopodium quinoa Willd. is an ancient food crop that has provided nutrition to Andean populations for thousands of years. BRS Piabiru is a quinoa genotype developed and adapted to tropical climate by the Brazilian Agricultural Research Corporation. In this work, BRS Piabiru quinoa was evaluated concerning its nutritional, physicochemical and phenolic composition and also its bioactive properties. This variety showed high carbohydrate and protein contents and a low-fat level, composed of 86% of unsaturated fatty acids, 60% of which are polyunsaturated fatty acids. Four organic acids were detected, with quinic acid as the most abundant, while α- and γ-tocopherols were the vitamin E isoforms found. Quercetin and kaempferol glycosides were the main phenolic compounds in the quinoa extract, which also revealed relevant antioxidant and antimicrobial activities, with no toxic effect. These results support the potential of BRS Piabiru quinoa as a nutritious food crop and a source of bioactive compounds.