ABSTRACT
The wine industry generates large quantities of by-products each year. Therefore, this work aimed to isolate and evaluate the oil and protein fractions of Japanese quince (Chaenomeles japonica, JQ) press residue, offering a partial utilization of valuable bioactive compounds of wine industry by-products. To study the JQ oil extract yield, composition and oxidation stability, we modified the co-solvent composition during the supercritical CO2 (SC-CO2) extraction of oil by adding different ethanol content. The remaining defatted material was used for the isolation of proteins. The SC-CO2 extraction yielded oil rich in polyunsaturated fatty acids, tocopherols, and phytosterols. The use of ethanol as a co-solvent increased the oil yield but did not enhance its oxidative stability or content of antioxidants. We recovered protein isolate after removing tannins with 70% ethanol extraction in the next step. The JQ protein isolate contained all essential amino acids. In addition to its balanced amino acid composition, the protein isolate exhibited excellent emulsifying properties highlighting its potential as a food additive. In conclusion, JQ wine by-products can be utilized for the extraction of oil and protein fractions which can be used in food or cosmetic product formulation.
ABSTRACT
Grapevine shoots and canes represent a significant amount of biomass, considered as a waste in viticulture. In cooler climates, grapevines are pruned in the autumn (October) and spring (March) due to harsh winter conditions (e.g., snow, low temperatures), and large amounts of biomass are produced at these different pruning times. This work was undertaken in order to investigate the potential of vineyard pruning waste for recovery of polyphenolic compounds for biomass valorization. Qualitative and quantitative analyses of grapevine shoot and cane polyphenols, including flavonoids and stilbenoids were performed using UHPLC MS/MS method. The results revealed the flavonols (quercetin) to be the most abundant compounds in shoots among all the three cultivars screened (Zilga, Hasansky Sladky, Rondo). Stilbenoids (ε-viniferin) dominated in the canes, while increased level of flavonols with lower contents of stilbenoids was detected in the endo-dormant canes, and higher amounts of flavanols and stilbenoids were recorded in eco-dormant canes. In conclusion, the content of polyphenols in grapevine shoots and canes differed among the cultivars and dormancy phases. The results generated from the present study contribute to the sustainable and environmentally friendly viticulture practice via valorization of vineyard pruning wastes.
