Unripe grapes: an overview of the composition, traditional and innovative applications, and extraction methods of a promising waste of viticulture

Abstract

Unripe grapes (UGs) are a waste product of grapevine cultivation and an emerging source of several compounds, such as organic acids, phenolic compounds, vitamins and mineral salts, of great economic importance to the pharmaceutical, cosmetic and food industries. Traditionally, products made from UGs, such as verjuice and sour grape sauces, have been used as seasoning or acidifying agents. The health effects of grape compounds are described as anti-inflammatory, cardioprotective, anticancer and antidiabetic, as often demonstrated by both in vitro and in vivo studies. Recently, UGs have received renewed attention because of the innovative potential applications of their extracts in food and beverages for purposes of preservation and enrichment with healthy compounds, or for direct use in the human diet. The aim of this article is to review the composition and properties of UG products and their traditional and innovative application in food and beverages.

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

“…It is obtained by pressing unripe grapes using physical pressure (De Matos et al, 2017;Özturk and Şengun, 2019). Australia, New Zealand, South Africa, the United States, and Spain were among the first countries in the world to grow and use unripe grapes (Fia et al, 2021).…”

“…In recent years, it has been used to prevent the enzymatic browning of fruits and vegetables (Tinello and Lante, 2017). It is also a common ingredient in Turkish sorbets (Ekici et al, 2018;Fia et al, 2021).…”

“…Verjuice is made from unripe grapes and contains compounds similar to those found in grape juice. It contains water, carbohydrates, protein, potassium, calcium, sodium, iron, phosphorus, ascorbic acid thiamine, niacin, and riboflavin (Fia et al, 2021). Unripe grapes have antioxidant and antimicrobial effects due to their rich structure of organic acids and phenolic compounds such as malic acid, tartaric acid, catechin, caffeic acid, gallic acid, and quercetin (De Matos et al, 2017;Özturk and Şengun, 2019;Turkmen et al, 2019).…”

Biomass estimation and characterization of the nutrient components of thinned unripe grapes in China and the global grape industries

“…Due to the rapid expansion of table grape planting area and the continuous improvement of viticulture management, fruit thinning has become a very extensive horticultural measure, so a large amount of solid waste such as thinned unripe grapes (TUR) is generated every year ( Guo et al, 2019 , Fia et al, 2021 , Wei et al, 2021 ). This new type of solid waste will be accumulated into the soil of the orchard and may become hosts for pathogens after decaying ( Dou et al, 2015 ), which accelerates the spread of crop diseases and increases the acidity of the soil, thereby disrupting the microbial community in the soil ( Mazzola, 1998 ).…”

“…Therefore, TUR gradually attracts people's attention ( Bovo et al, 2016 , Fia et al, 2021 , Gutiérrez-Gamboa et al, 2020 , Piccardo et al, 2019 , Tinello and Lante, 2017 ) and becomes an urgent problem for the grape industry. Previous studies have revealed that grape juice made from TUR could be used as food-flavoring agent ( Dupas de Matos et al, 2018 ), such as replacing vinegar to make salad dressings and pickles.…”