The impact of seeds on anthocyanin extraction from skins was assessed on four Italian red winegrape varieties presenting different anthocyanin profile. Grape skins were macerated alone or in presence of seeds for ten days in model solutions. Aglianico, Nebbiolo, Primitivo, and Sangiovese cultivars showed differences in the anthocyanin extraction rate, content, and profile. The presence of seeds did not significantly affect the anthocyanin content and forms extracted from skins and kept into solution, but it generally led to an increase in the polymerization rate. For the first time, anthocyanins adsorbed on seed surface have been quantified after maceration. The amount of anthocyanins retained by seeds was less than 4 mg/kg berries and it seems variety-dependent, with a possible role of seeds number and weight. Individual anthocyanin forms were adsorbed mainly according to their abundance in the solution, but cinnamoyl-glucoside anthocyanin forms showed a higher affinity with seed surface.

This study investigates the effects of maceration temperature (24 or 29 °C) and duration (12, 18, or 24 days) on phenolic compounds during 'Nebbiolo' wine-like extraction and lab-scale winemaking. In wine-like maceration, anthocyanins quickly peaked and then decreased, with temperature alone showing limited influence on extraction or degradation. In lab-scale fermentations, the rapid anthocyanin extraction at 29 °C was followed by higher degradation, driven by fermentative enzymatic activities and evidenced by increased skin softening at higher temperatures. Longer macerations led to less wine anthocyanins. Tri-substituted anthocyanins were better preserved at 24 °C. Tannin content and structure were minimally affected. Phenolic analyses of grapes, wine, pomace, and lees revealed the extracted, unextracted, resorbed, and degraded phenolic fractions. Reduced anthocyanins in pomace at higher temperatures or extended maceration indicated enhanced extraction and subsequent degradation. The study introduces a "phenolic budget" concept, highlighting the interplay of maceration parameters shaping 'Nebbiolo' wine phenolics.

This study investigated tannin extraction in four Italian red grape varieties — ‘Aglianico’, ‘Nebbiolo’, ‘Primitivo’, and ‘Sangiovese’. The grape initial tannin content was characterized through a potential extraction. Moreover, the extractable phenolic content was evaluated through maceration in wine-like solution of skins, seeds, and their combinations for 10 days, with ethanol concentration incrementally adjusted to simulate fermentation. Texture analysis of grape seeds and skins was conducted before and after the wine-like solution macerations. Results revealed variety-dependent differences in the mechanical and acoustic properties of grape skins and seeds, with seeds showing increased acoustic energy upon breakage. Grape varieties showed differences in skin and seed phenolic pools and extractability. Significant positive correlations were found between potential and extractable tannin content. Smaller, less galloylated flavan-3-ols were well extracted in model wine solutions. Extraction curves were examined from skins, seeds, and combined skins + seeds matrices, evidencing a faster skin phenolics extraction than seeds. Interestingly, tannin extraction from skins + seeds did not correspond to the sum of individual skin and seed extractions. Moreover, the skin-to-seed tannin ratio and tannin structural characteristics also varied between skin and seed joint and separate extractions.

Cold liquid stabulation aims to extract valuable compounds from grape lees before juice clarification. In this study, 7, 14, and 21 days of lees contact were tested on aroma-neutral 'Arneis' and 'Cortese' grape juices vs control. Basic parameters, colour, polyphenols, antioxidant capacity, and volatile organic compounds were assessed throughout winemaking. Wine sensory analysis was performed. The produced wines did not differ in terms of colour and show limited differences in polyphenols, not influencing astringency and bitterness. Variety and treatment length influenced free and glycosylated volatile organic compounds. Free terpenes increased in the 21-day treated 'Arneis' wine (+67 %). Lower free esters in 'Arneis' with 14 days of stabulation were found (-10 %). On the contrary, higher values of individual esters were found in 14 and 21-day treated 'Cortese' wines, but these showed lower free C6 (-12 %) and sulphur compounds (-23 % and - 24 %, respectively), and higher overall wine quality with respect to non-stabulated wine.

BACKGROUND: Sforzato di Valtellina (Sfursat) is a PDO reinforced red wine produced in Valtellina (northern Italy) from partially withered red grapes (Vitis vinifera L.) cv. Nebbiolo. The present study aimed to evaluate the combined influence of different grape ripeness levels and withering length on the chemical composition, mechanical properties, and phenolic profile of Nebbiolo winegrapes from two Valtellina vineyards. During three consecutive vintages (2019, 2020, and 2021), three different technological binomials have been tested: early harvest/long withering (EL), medium‐term harvest/medium‐term withering (MM), and late harvest/short withering (LS).RESULTS: At the end of the withering process, EL thesis usually presented the highest values of sugars and acidity. Extractable seed polyphenols showed a decreasing trend by leaving the grapes on the plant longer, and this effect increased considerably after withering with respect to fresh samples. EL and MM evidenced the greater concentration of these compounds expressed on grape weight, particularly for tannins. Instead, skin‐extracted total phenolics were less influenced by the harvest time, whereas their concentration increased after withering. The harvest time appears to have a higher impact than the withering length on the final extractable anthocyanin content, although the trend was no stable during the vintages or common for the two vineyards evaluated. EL and MM experienced the highest contents of grape skin tannins in most cases, suggesting that a longer withering increases their concentration.CONCLUSION: Harvest time and withering length can be modulated according to the desired oenological objective, promoting the valorization of grape potentialities. The choice to harvest the grapes earlier and enhance the withering length should be preferred to obtain wines with higher acidity and phenolic content, more suitable for long‐ageing period. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.