engleski

Impact of mash maceration duration and temperature on non-flavonoid phenolics in Malvazija istarska wines

Phenolic acids and stilbenes are important groups of non-flavonoid phenolic compounds present in grapes and wine. Their content in wine may be modulated by the vinification technique applied. The present study aimed to determine the impact of the application of different grape mash maceration treatments on the composition of hydroxycinnamic (HCA) and hydroxybenzoic acids (HBA) and stilbenes in Malvazija istarska wines. The research was conducted at the Institute of Agriculture and Tourism (Poreč, Croatia) with Malvazija istarska (Vitis vinifera L.), an autochthonous Croatian white grape variety. A total of six vinification treatments were carried out: two days maceration treatment at 8 °C (CRYO), and seven (M7), 14 (M14), 21 (M21), and 42 days (M42) maceration treatments at 16 °C, compared with the control treatment without maceration (C). Identification and quantification of phenolic acids and stilbenes was performed after direct injection of the filtered wine sample, using a high performance liquid chromatograph (HPLC) equipped with a diode array detector (DAD). The obtained results were statistically processed by one-way analysis of variance (ANOVA) and Fisher's test of least significant differences (LSD). According to the obtained results, the highest concentration of total HBAs was recorded in prolonged post-fermentative maceration treatment M42, and among all HBAs gallic acid had significantly the highest concentrations. Regarding HCAs, the total content was significantly the highest in seven days maceration treatment (M7), while in longer maceration treatments (M14, M21, M42) total HCA content 58 gradually decreased as maceration progressed. When observing individual HCAs, transcaftaric acid had the highest concentrations, especially in M7 treatment wine, while caffeic and ferulic acids reached the highest concentrations in pre-fermentative two days (CRYO) treatment. Regarding total stilbene content, treatments M7, M14, and M21 obtained the highest concentrations, but did not significantly differ between each other, and when observing individual stilbenes, cis-piceid concentrations were the highest in those treatments and among all identified stilbenes. Obtained results show that HBA content benefits from the prolonged maceration, while for the most HCAs and stilbenes concentrations increase up to seven days of maceration and then decrease during prolonged maceration, possibly due to oxidation and other reactions.

Malvazija istarska ; maceration ; non-flavonoid phenolics

nije evidentirano