Characterization of Unripe Grapes (Vitis vinifera L.) and Its Use to Obtain Antioxidant Phenolic Compounds by Green Extraction

Abstract

Thinning pruning is a process in modern viticulture to improve product quality when grapes are still in the immature fruit stage. Unripe grapes, which are waste, are mostly consumed locally as verjuices to meet domestic demand. This study aims to optimize a more efficient “green” technique for the extraction of total phenolic compounds (TPC) and antioxidant capacity (AC) from three varieties of unripe grape juice by response surface method (RSM) using ultrasound-assisted extraction (UAE). The influence of temperature (25–65°C) and extraction time (5–30 min) on total phenolic content (TPC) and antioxidant capacity (DPPH and CUPRAC) was investigated. In this study, physicochemical properties, mineral composition, phenolic and organic acid components of three different verjuices were also investigated. As a result, the optimal extraction points for extraction time (12 min) and temperature (30°C) were determined. All independent variables were found to be significantly effective on TPC and AC content during UAE. Verjuices are a rich source of antioxidants, phenols, organic acids, minerals, and vitamin C. This study is expected to contribute to the evaluation of unripe grape wastes, which are very rich in bioactive components, and to increase its economic potential by expanding local production, thus contributing to sustainable agri-food processing.

A comparison of Nine Grape Vitis vinifera L. Cultivars Growing in Iraq’s Kurdistan Region in Terms of Their Vegetative Growth and Physicochemical Traits

“…In another research [26] used 21 Spanish-origin grape cultivars found that concentration of phenolic compounds ranged from (92.1 to 468 mg 100g -1 ). The range of phenolic compounds in grapes changing depending on some factors such as cultivar, maturation level, ripening duration and grape components, year of production, and some environmental factors such as soil, climate and agricultural practices [27,28]. The researcher [29] found that tartaric acid in 24 grape cultivar ranging from (0.53 to 13.16%).…”

Assessment of the influence on Hypsizygus marmoreus stem waste as a sustainable alternative to corn in Holdobagy geese dietary

“…Mushrooms contain various phenolic compounds, which are generally believed to be related to antioxidant activity (Bayram and Karabacak, 2022;Moazzen et al, 2022), with phenolic compounds in mushrooms reportedly possessing the ability to remove LDL-C (Tang et al, 2016), Mushrooms also contain vitamin C and selenium, which have antioxidant properties (Lauridsen et al, 2021;Rathore et al, 2022). Six antioxidants can be extracted from H. marmoreus (Cai et al, 2020), and polysaccharides extracted from H. marmoreus can improve the antioxidant status by enhancing CAT, SOD, GSH-Px, and T-AOC, and reducing MDA (Liu et al, 2018).…”

Screening and Characterization of Phenolic Compounds from Selected Unripe Fruits and Their Antioxidant Potential

“…are the most prominent fruits on earth, with an annual production of over 75 million tons. The industry primarily uses grates to screen out many unripe grapes, which are then dumped into agricultural land [ 5 , 6 ]. Several potentially bioactive compounds, such as organic acids, phenolic compounds, vitamins, and minerals that are highly beneficial to human health, cosmetics, and biomedical areas, are thought to have been recently discovered in unripe grapes [ 7 ].…”