Abstract
Several by-products are generated by de-stemming, pressing, and
decantation steps during the wine making process. ese materials
are very rich in biodegradable organic matter and can support microbial growth and emission of environmentally undesirable odors and
compounds. e wine residues, if not treated eciently, have the
potential to initiate environmental hazards ranging from surface and
groundwater pollution to foul odors. Indeed, a signicant negative
environmental impact is seen due to discharge of wine waste (News
2014) and signicant nes have been issued for dumping of wine
residues (Devesa-Rey et al. 2011; EPA 2014). Inappropriate disposal of grape pomace attracts ies and pests and this can create
unwanted hazards (Bustamante et al. 2007). In some cases, where
the wine solid residues are used as fertilizers or composts at excessive rates, plant growth is aected due to nitrogen immobilization
or an increase of nitrogen leaching in soils treated with wine solids (Flavel et al. 2005; Bustamante et al. 2007). Supplementation
of the wine by-product composts with minerals and micronutrients
such as phosphorous can lead to problems pertaining to their heavy
metal content (Del Castilho et al. 1993; Karaka 2004). Pinamonti
et al. (1997) argued that the heavy metal content is a critical factor leading to restricted agriculture use of wine waste compost.
Furthermore, tannins and other compounds from pomace can
cause oxygen depletion in the soil and inltrate surface, soil and
groundwaters (Arvanitoyannis et al. 2006). e problems mentioned
indicate that current wine waste management practices can potentially lead to serious environmental pollution. It is becoming more4.8.5 Grape-Seed Oil 171
4.8.6 Non-Food Applications 1734.9 Fermentation174
4.10Green Material1754.10.1 Grape Stalks175
4.10.2 Grape Leaves 1764.11 Challenges and Opportunities 177
Acknowledgments 177
References 178important and a subject of increasing concern for wine processors
and scientists to nd a safe and economical use for grape and wine
waste. Furthermore, utilization of wine by-products and the production of environmentally sustainable wine can have marketing advantage. Research from New Zealand indicated that consumers support
the purchase of wine produced by green production practices and
are prepared to pay a higher price for sustainably produced wine
(Forbes et al. 2009). By-products generated from wine making can
be broadly classied as follows: solid by-products (stalks and grape
pomace), highly viscous by-products (wine lees), and low-viscosity
by-products (wastewater) (Figure 4.1). e physical nature of the
materials can to a large extent aect their economic potential for
utilization, inuencing the composition and level of compounds
of interest as well as the costs associated with bioconversion and
maintaining the stability of the by-product (i.e., handling of solids
or liquids will need dierent engineering requirements and storage
of the material will depend on their stability against microbial and
oxidative processes). Grape pomace (GP) is equivalent to about 20%of the grapes used in wine making and is responsible for the largest
amount of by-product generated from wine making with an estimated 10,930,834 Mt (Van Dyk et al. 2013). Grape pomace contributes to approximately 62% of the organic waste (Naziri et al. 2014)
and therefore practical utilization is an urgent issue from an environmental perspective. GP may contain grape skin and pulp (10%–12%
of grapes), seeds (3%–6%), and stalks (2.5%–7.5%) (Wadhwa et al.
2013) (Figure 4.2). e composition depends largely on the wine
production system (white wine versus red wine), the grape variety and
maturity, production size, the use of machinery for the separation of
grapes before crushing, separation techniques used, and type of wine
variety that is being produced. Several compounds can be recovered
from GP such as oil (12%–17% of the grape seeds weight), protein,
carbohydrates (up to 15% sugars and 30%–40% ber), phenolics/
pigments (0.9%), and tartrate (0.05%–0.08%), which are suitable for
a range of useful products that can be used in food, pharmaceutical,
and agricultural industries. Given the massive amounts produced
and its organic load, the utilization of GP is seen as an important
activity to eliminate the environmental problems associated withthe disposal of GP as well as an opportunity to add value and generate extra income from the by-product. Lees and stalks represent
signicant sources of organic waste, 14% and 12% of organic byproduct generated during wine making, respectively (Naziri et al.
2014). Grape seeds can be separated from GP and used for the
production of linolenic-rich oil (12%–20%), carbohydrates (60%–
70%), protein (about 11%), and phenolics (5%–8%) (Naziri et al.
2014) (Figure 4.3). ese valuable compounds have several useful
applications as animal feed, and food, cosmetic, and pharmaceutical ingredients. e conventional uses of solid wine by-products are
animal feed (Louli et al. 2004) and fertilizer/compost (Kammerer
et al. 2005) without or with little further processing. However, in
recent years, there has been a growing interest in the exploitation
of wine industry waste in other applications as the awareness of the
potential commercial value has become known. For example, it was
found that during the wine making process, while soluble phenolic compounds that are present in the vacuoles of the plant cells
are extracted, a large amount of phenolic compounds bound to thecell walls are not (Meyer et al. 1998). Compounds extracted from
wine by-products with high phenolic content may be able to exert
positive eects on human health, to protect against cardiovascular
disease, to produce anti-inammatory activity and anticarcinogenic
eects as well as being used as food antioxidants (Shrikhande 2000;
van de Wiel et al. 2001; Khanna et al. 2002). Many researchers have
reported that the extracted natural antioxidants and various phenolic compounds from wine by-products, including grape seeds, skin,
exhausted pomace, grape stalks, wine lees, and grape pomace, are
safer to use than synthetic antioxidants (Alonso et al. 2002; Negro
et al. 2003; Arvanitoyannis et al. 2006). e recovery and utilization of winery by-products could not only reduce the waste disposal burden and other environmental issues, but could also lead to
the development of new healthier, robust ingredients, and extract
compounds for both the pharmaceutical and food industries. Due
to the aforementioned benecial properties, wine by-products are
now available as dietary supplements. Products such as GSE, grape
extract, and red wine powder are sold commercially. Table 4.1 summarizes the physicochemical properties and potential use of wine
by-products. Recently, viable new business opportunities have
emerged from within the wine industry. ere is an increasing interest from several industries, including the food industry, to utilize
antioxidants and other phenolics from wine by-products and this
has resulted in several applications being developed. One of these is
the extraction of anthocyanins, known as “enocyanin,” to be utilized
as food colorants (Alonso et al. 2002). Patents have been awarded
to researchers related to their work in processing and developing
commercial products in cosmetic and pharmaceutical industries
from grape seeds, skin, and related avonoids (Carson et al. 2001;
Henry et al. 2001; Pykett et al. 2001; Ray and Bagchi 2001). Other
than human-orientated applications, wine waste can also potentially
be utilized for alternative applications such as absorption of heavy
metals (namely lead and cadmium) (Farinella et al. 2007); and for
the production of pullulan, a polysaccharide that has many food and
pharmaceutical applications (LeDuy and Boa 1983). An interesting
and newly reported approach toward the integrated utilization of
grape skins consists of consecutive or simultaneous extraction with a
neutral organic solvent and water under reux (Mendes et al. 2013).