Effects of Latitude and Weather Conditions on Proanthocyanidins in Blackcurrant (Ribes nigrum) of Finnish Commercial Cultivars.

Blackcurrants of three Finnish commercial cultivars 'Mortti', 'Ola', and 'Melalahti' cultivated in southern and northern Finland were compared on the basis of the content and composition of proanthocyanidins (PAs). Seventeen B-type PA oligomers (degree of polymerization 2-5 and 7) were detected by hydrophilic interaction liquid chromatography and electrospray ionization mass spectrometry. Total PAs, dimers, trimers, and tetramers were quantified. Among the three cultivars, 'Ola' had the highest contents of both total PAs and PA oligomers. 'Melalahti' was separated from both 'Mortti' and 'Ola' by PA profiles in the partial least-squares discriminant analysis model. All three cultivars revealed distinct responses to latitude and weather conditions. The content of total PAs showed a positive correlation to latitude in 'Ola' and 'Melalahti'. Among the meteorological variables, high temperature and radiation correlated negatively with total PAs, while only specific variables showed a correlation with PA oligomers.

Thinned stone fruits are a source of polyphenols and antioxidant compounds.

BACKGROUND: Thinned fruits are agricultural by-products that contain large quantities of interesting compounds due to their early maturity stage. In this work, the phenolic profile and the antioxidant activity of six thinned stone fruits (apricot, cherry, flat peach, peach, plum and nectarine) have been investigated, focussing on proanthocyanidins. RESULTS: Thinned nectarine had the highest content of total phenols [67.43 mg gallic acid equivalents (GAE) g-1 dry weight (DW)] and total flavonoids (56.97 mg CE g-1 DW) as well as the highest antioxidant activity measured by DPPH scavenging (133.30 mg [Trolox equivalents (TE) g-1 DW] and FRAP assay (30.42 mg TE g-1 DW). Proanthocyanidins were very abundant in these by-products, and the main phenolic group quantified in cherry (10.54 mg g-1 DW), flat peach (33.47 mg g-1 DW) and nectarine (59.89 mg g-1 DW), while hydroxycinnamic acids predominate in apricot, peach and plum (6.67, 22.04 and 23.75 mg g-1 DW, respectively). The low, mean degree of polymerisation of proanthocyanidins suggests that their bioavailability could be very high. CONCLUSIONS: This study shows that thinned stone fruit extracts might be used as antioxidants in foods or as a source of compounds with health-related benefits that can be used in the pharmaceutical, cosmetic and food industries. © 2016 Society of Chemical Industry.

Reutilization of mango byproducts: study of the effect of extraction solvent and temperature on their antioxidant properties.

UNLABELLED: Mango biowastes, obtained after processing, contain large amounts of compounds with antioxidant activity that can be reused to reduce their environmental impact. The present study evaluates the effect of solvent (methanol, ethanol, acetone, water, methanol:water [1:1], ethanol:water [1:1], and acetone:water [1:1]), and temperature (25, 50, and 75 °C) on the efficiency of the extraction of antioxidants from mango peel and seed. Among the factors optimized, extraction solvent was the most important. The solvents that best obtained extracts with high antioxidant capacity were methanol, methanol:water, ethanol:water, and acetone:water (ß-carotene test, antioxidant activity coefficient 173 to 926; thiobarbituric acid reactive substances test, inhibition ratio 15% to 89%; 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid ABTS(·+); and 2,2-diphenyl-1-picrylhydrazyl DPPH· scavenging, 7 to 22 and 8 to 28 g trolox equivalent antioxidant capacity [TE] per 100 g mango biowaste on a dry matter basis [DW]). Similarly, the flavonoid (0.21 to 1.4 g (+)-catechin equivalents per 100 g DW), tannin (3.8 to 14 g tannic acid equivalents per 100 g DW), and proanthocyanidin (0.23 to 7.8 g leucoanthocyanidin equivalents per 100 g DW) content was highest in the peel extracts obtained with methanol, ethanol:water, or acetone:water and in the seed extracts obtained with methanol or acetone:water. From the perspective of food security, it is advisable to choose ethanol (which also has a notable antioxidant content), ethanol:water, or acetone:water, as they are all solvents that can be used in compliance with good manufacturing practice. In general, increasing temperature improves the capacity of the extracts obtained from mango peel and seed to inhibit lipid peroxidation; however, its effect on the extraction of phytochemical compounds or on the capacity of the extracts to scavenge free radicals was negligible in comparison to that of the solvent. PRACTICAL APPLICATION: There are many antioxidant compounds in mango peel and seed, and they could be used as a natural and very inexpensive alternative to synthetic food additives. However, the conditions in which the antioxidants are extracted must be optimized. This work proves that conditions such as extraction solvent or temperature have a crucial impact on obtaining extracts rich in antioxidants from mango biowastes.