engleski

Impact of pre-fermentative mash cooling, heating, saignée technique and prolonged macerations on antioxidant capacity and total phenolic content in Teran red wine

This study aimed to determine antioxidant capacity and total phenolic content in red wine obtained from cv. Teran (Vitis vinifera L.), autochtonous Croatian grape variety. Five different vinification treatments were submitted to: 48-hour pre-fermentative mash cooling (8 °C) followed by prolonged post-fermentative maceration of 13 days (C15), 28 days (C30), and saignée technique (juice runoff) proceeded with maceration of 13 days (CS15) ; and to 48-hour heating (50 °C) followed by maceration of 13 days (H15) and 28 days (H30). Also, this experiment included a control treatment (K7), with a standard 7-day maceration. The antioxidant capacity of the wines was determined by the ferric reducing/antioxidant power (FRAP) assay and the oxygen radical absorbance capacity (ORAC) assay. Fluorescence was measured by spectrofluorometer. The FRAP assay results are expressed in mmol/L FeSO4 × 7H2O, and the ORAC assay results are expressed as mmol/L of Trolox equivalents (TE). Total phenolic content (TPC) was determined by the Folin–Ciocalteu colorimetric method using a UV/Vis spectrophotometer. The results are expressed as gallic acid equivalents in mg/L of wine (mg GAE/L). Obtained results showed that both FRAP and ORAC assay values in all treatments were significantly higher compared to the control treatment (K7). Also, the two assays showed a strong correlation (r= 0.998). FRAP assay values ranged from 10.77 to 23.67 mM Fe2+, and ORAC assay values ranged from 17.77 to 31.67 mM Trolox. The highest values of both assays were obtained in treatment submitted to pre-fermentative heating and 30-day maceration (H30). Total phenolic content varied from 821.52 mg GAE/L in control wine (K7) to significantly the highest value, 2710.61 mg GAE/L in treatment where saignée technique and 15-day maceration were performed (CS15). In comparison to control wine (K7) TPC in all treatments was statistically higher. Obtained results suggested a noticeable impact of saignée technique and 15-day maceration on TPC, and the impact of pre-fermentative mash heating and 30-day maceration on antioxidant capacity. According to our results, Teran red wine, affected by particular vinification processes considered a strong source of bioactive compounds, as well their beneficial properties can contribute to human health.

Teran red wine, pre-fermentative procedures, prolonged maceration, total phenolic content, antioxidant capacity

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