ABSTRACT
This study aimed to investigate the effects of spontaneous fermentation on physicochemical characteristics, bioactive compounds, and antioxidant activity of acerola and guava fruit industrial by-products. Viable cell counts of lactic acid bacterial (LAB) in acerola and guava by-products were ≥ 5.0 log CFU/mL from 24 h up to 120 h of fermentation. Fermented acerola and guava by-products had increased luminosity and decreased contrast. Contents of total soluble solids and pH decreased, and titrable acidity increased in acerola and guava by-products during fermentation. Ascorbic acid contents decreased in acerola by-product and increased in guava by-product during fermentation. Different phenolic compounds were found in acerola and guava by-products during fermentation. Fermented acerola and guava by-products had increased contents of total flavonoids, total phenolics, and antioxidant activity. The contents of total flavonoids and total phenolics positively correlated with antioxidant activity in fermented acerola and guava by-products. These results indicate that spontaneous fermentation could be a strategy to improve the contents of bioactive compounds and the antioxidant activity of acerola and guava by-products, adding value and functionalities to these agro-industrial residues.
ABSTRACT
The aim of this study was to evaluate the phenolic composition, sugars, and organic acids by HPLC-DAD/RID, and the antioxidant capacity of 100% commercial 'Syrah' and 'Tempranillo' red wines from the San Francisco Valley-SFV wineries, and to compare them with commercial monovarietal wines of the same cultivars from countries such as South Africa, Spain, Chile, and Australia. In total, 25 phenolic compounds were quantified and classified into chemical groups in all wines (phenolics acids, flavanones, flavan-3-ols, flavonols, anthocyanins, and stilbenes). Among these, catechin, procyanidins B1 and B2, lactic acid, and antioxidant capacity were highlighted as the markers responsible for the typification of SFV wines when compared to wines from temperate regions. The data reported here contribute to the knowledge of the potential for producing quality wines in tropical climate regions. The wines of cultivars 'Syrah' and 'Tempranillo' are consolidated among the wineries in the SFV region, Brazil, due to their excellent adaptation to the semi-arid tropical climate. The SFV recently applied for a wine geographical indication as its wines are young with tropical climate typicity. This study shows that it is possible to differentiate SFV Syrah and Tempranillo wines from other world regions by HPLC molecular profile using chemometric techniques. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05739-7.
ABSTRACT
In this study honey samples produced by Melipona (Michmelia) seminigra merrillae, collected in seven counties distributed in the central and southern region of Amazonas state in Brazil, were analysed for their botanical origin, content and profile of phenolic compounds, and antioxidant and antimicrobial activities. Twenty-two pollen types were identified. The total phenolic content ranged from 17 to 66 mg GAE/g of extract; the highest contents were found in honeys produced from pollen types such as Clidemia and Myrcia. The antioxidant activity was higher in the samples that contained higher quantities of phenolic compounds. In relation to the antibacterial activity, samples CAD3, CAD4 and SAD3 presented the best results. Fourteen phenolic compounds were determined. Among them, we identified the flavonoid taxifolin, which has not previously been described in honeys from stingless bees, and we report the identification of catechol in Brazilian honey samples for the first time.
