Abstract
Approximately, 67.1 million tons of grapes were utilized in wine production in 2013 (FAO 2014). is generates a considerable amount of waste because as much as 20% of the weight of processed grapes is not found in the nal product (Mazza and Miniati 1993). Figure 3.1 shows the vinication process and waste materials generated at each production step. e three main by-products that are generated from wine making are stalks, grape pomace/marc, and wine lees (Bustamante et al. 2008). Stalks and grape pomace (comprising skin, seeds, and pulp) are left over after crushing, draining, and pressing ( Jin and Kelley 2009). Wine lees is a sludge (or mud-like) material generated in the wine making process. is material contains dead yeast, yeast residue, or particles precipitated at the bottom of wine tanks or barrels (Hwang et al. 2009). Waste contains signicant amounts of organic species (such as sugars, phenolics, polyalcohols, pectins, and lipids) with high chemical and biological oxygen demand and is therefore recognized as an environmental pollutant (Lafka et al. 2007). ere is growing interest in the utilization of this waste including its conversion into biofuels and use as nutrient supplements, food ingredients, and animal feeds. For example, Shirikhande (2000) and González-Paramás et al. (2003) reported that extracts from grape seeds and skin contain phenolic compounds that can be used as dietary supplements for better health and well-being. Many studies have investigated the use of waste derived from grapes as a source of natural antioxidants with most of the focus being on the skins, stalks, and seeds (Van Dyk et al. 2013; Wadhwa and Bakshi 2013; Naziri et al. 2014). However, the utilization of waste from wine production, particularly wine lees, is still poorly investigated.