Assessment of Bioactive Phenolic Compounds and Antioxidant Activity of Blackberry Wines

Blackberry wine is a natural source of bioactive phenolic compounds that have profound antioxidant potential. The objectives of the present research were to assess the phenolic compounds and antioxidant activity of blackberry wines (BW), and to use the chemometric analysis to differentiate among the two groups of samples, i.e., conventional and organic. Fifteen BW samples were analyzed for their total polyphenol index, total polyphenols, total flavonoids, total tannins, total monomeric anthocyanins and antioxidant activity by the appropriate spectrophotometric methods. The concentrations of individual phenolic acids (gallic acid, chlorogenic acid, caffeic acid, p-coumaric acid and cinnamic acid) and trans-resveratrol were determined by high-performance liquid chromatography. A comparison between the two groups of investigated BW samples revealed a statistically significant difference in the concentration of caffeic acid and p-coumaric acid, both being higher in the organic BW samples. Furthermore, the results showed a series of statistically highly significant relationships between the analyzed constituents (caffeic acid and p-coumaric acid). The antioxidant activity of the investigated wines was proportional to the concentrations of bioactive phytochemicals.

Blackberry wines mineral and heavy metal content determination after dry ashing: multivariate data analysis as a tool for fruit wine quality control

This study brings out the data on the content of 21 mineral and heavy metal in 15 blackberry wines made of conventionally and organically grown blackberries. The objective of this study was to classify the blackberry wine samples based on their mineral composition and the applied cultivation method of the starting raw material by using chemometric analysis. The metal content of Croatian blackberry wine samples was determined by AAS after dry ashing. The comparison between an organic and conventional group of investigated blackberry wines showed statistically significant difference in concentrations of Si and Li, where the organic group contained higher concentrations of these compounds. According to multivariate data analysis, the model based on the original metal content data set finally included seven original variables (K, Fe, Mn, Cu, Ba, Cd and Cr) and gave a satisfactory separation of two applied cultivation methods of the starting raw material.

Effect of maturation on wild apricot vermouth of different treatments

Wild apricot vermouths (WAV) of different sugar levels (8, 10 and 12 °Brix), different alcohol levels (15, 17 and 19%) and spice levels (2.5 and 5%) were prepared. The product was matured for six months and evaluated for physico- chemical characteristics at 0, 3 and 6 months of maturation. In general, ethyl alcohol content decreased in wild apricot vermouth of all treatments during maturation for six months, in proportion to their initial values. The decrease in TSS was revealed with the advancement of the storage period of six months. A similar trend was observed for total sugars with the advancement of the ageing period. The amount of reducing sugars, however, increased with the prolongation of the maturation period. The total esters content in WAV increased with the advancement of the ageing period, irrespective of their alcohol content. However, the volatile acidity showed a very little increase during ageing but remained non-significant among the different treatments. Total phenols content in WAV decreased by both the ageing period of six months and an increase in alcohol level. A non-significant increase in the titratable acidity with an ageing period was observed in all the WAV having different alcohol levels. The effect of spice extract levels added in the preparation of WAV showed that with the advancement of storage period total esters increased from 246.8 to 272.8 mg/L and 252.8 to 280.6 mg/L for WAV having 2.5 and 5% spices content, respectively. In brief, an overview of the entire results revealed that there was an interactive effect of alcohol level, the sugar level and the spice extract during maturation of wild apricot vermouth. It can be concluded that the maturation of WAV exerted a favourable effect on physico-chemical properties of wild apricot vermouth and is thus, considered desirable.

Polyphenolic content, antioxidant activity and metal composition of traditional blackberry products

In this study, commercially available traditional blackberry products, namely blackberry wines and blackberry elixirs from Coastal Croatia and Bosnia and Herzegovina, were investigated as sources of bioactive compounds, essential nutrients and metals. Samples were analysed for pH, total polyphenols and monomeric anthocyanins content, individual phenolic acids (gallic acid, chlorogenic acid, caffeic acid and p-coumaric acid), antioxidant activity (DPPH and ABTS), reducing power (RPA), total nitrogen and phosphorus as well as metals (K, Na, Ca, Mg, Fe, Mn, Cu, Zn, Co, Cr, Cd). The results of this study showed that the studied traditional blackberry products are rich sources of polyphenols and their consumption could increase the daily intake of dietary antioxidants in humans. In addition, both groups of traditional blackberry products could be considered safe for health and good additional sources of essential minerals such as manganese and potassium. The concentrations of the analysed undesirable toxic and potentially toxic metals in the studied blackberry products were below the maximum allowable concentrations defined by various regulations for wines and fruit wines.