Effect of thermomaceration and enzymatic maceration on phenolic compounds of grape must enriched by grape pomace, vine leaves and canes

Characterization of an Antioxidant-Enriched Beverage from Grape Musts and Extracts of Winery and Grapevine By-Products

“…Temperature was set at 60 • C using a Thermo/Haake DC10-K10 circulating heating bath (Haake, Karlsruhe, Germany), while the extraction vessel was duly covered by parafilm and aluminum foil to avoid solvent loss and light influence. The process time was fixed at 4, 6, and 8 h for cane, pomace, and leaf samples, respectively, in order to achieve a grape must with a maximum amount of polyphenols and antioxidants [23]. Then, enriched grape juice was prepared by mixing pomace, leaf and cane extracts as follows: after filtration using 20-25 µm nylon filter bags, pomace, leaf, and cane extracts were mixed in a ratio of 40:20:40 (v/v/v).…”

“…Additionally, total antioxidant capacities were evaluated by the ABTS (2,2 -azinobis(3-ethylbenzothiazoline -6-sulfonic acid)) radical cation assay, CUPRAC (cupric reducing antioxidant capacity) method, ORAC (oxygen radical absorbance capacity)-fluorescein (FL), and ORAC-pirogallol red (PGR) assays, as described previously [23,[28][29][30]. In all of the assays, Trolox was used as reference compound and results were expressed in terms of mmol Trolox equivalent antioxidant capacity per kg of sample.…”

Recent Advances and Applications of Pulsed Electric Fields (PEF) to Improve Polyphenol Extraction and Color Release during Red Winemaking

“…As the majority of the compounds responsible for the quality and stability of wine color (polyphenolic compounds, colour precursors, tannins) are located in the grape skin vacuoles of the grape berries, the mass transfer is a critical mechanism for achieving their efficient extraction, and the winemaking techniques aim to increase the permeability of cytoplasmic membranes to facilitate their release; however, an effective extraction of such compounds strongly impacts the industrial process in terms of duration and cost. Different techniques have been developed to enhance the extraction of polyphenols and pigmented compounds improving the performances of the static maceration: thermovinification, grape freezing, the use of maceration enzyme, among others, have been tested on pilot and industrial scales [19][20][21]. To date, many of these approaches require a significant amount of energy and cause losses of valuable nutraceuticals: conducting alcoholic fermentation at high temperatures can cause fermentation failures and loss of volatile compounds, freezing grapes was demonstrated to affect the wine quality on different extents, and commercial formulations of maceration enzymes provide different levels of purity and potential contamination of detrimental species like β-glucosidases [22][23][24].…”

Aroma characterization of grape juice enriched with grapevine by-products using thermomaceration

“…After vintage, autumn leaves and canes were cut and stored at -20 °C until processing. Compounds from grape pomace, grapevine leaf and cane samples were extracted by thermomaceration as previously reported (Aguilar et al, 2016). After filtration using 20-25 µm nylon filter bags, extracts of pomace, leaves and canes were mixed in a proportion of 40:20:40% (v/v/v), respectively.…”

“…However, hot break processing should be used carefully, especially with immature fruit, as it may result in the persistence of green aromas in grape juice (Iyer et al, 2010). Recently, thermomaceration has been used as a green extraction technique to fortify grape juice with antioxidant compounds from grape pomace, grapevine leaves and canes (Aguilar et al, 2016). Nevertheless, the potential of winery and grapevine by-products as a source of aroma compounds has still received small attention.…”