1
GREEN EXTRACTION
MARTINA PĆREZ-SERRANO AND TOMĆS LANDETE-CASTILLEJOS
Animal Science Techniques Applied to Wildlife Management Research Group, Instituto de InvestigaciĆ³n en Recursos CinegĆ©ticos, Albacete Section of CSIC-UCLM-JCCM, Universidad de Castilla-La Mancha, Campus Universitario sn, 02071, Albacete, Spain SecciĆ³n de Recursos CinegĆ©ticos y Ganaderos, Instituto de Desarrollo Regional of Universidad de Castilla-La Mancha, Campus Universitario sn, 02071, Albacete, Spain Departamento de Ciencia y TecnologĆa Agroforestal y GenĆ©tica, Escuela TĆ©cnica Superior de Ingenieros AgrĆ³nomos y Montes of Universidad de Castilla-La Mancha, Campus Universitario sn, 02071, Albacete, Spain
LUIS ROCA-PĆREZ
Department of Vegetal Biology, Faculty of Pharmacy, Universitat de ValĆØncia, Avda. Vicent AndrĆ©s EstellĆ©s, s/n 46100 Burjassot, ValĆØncia, Spain
MLADEN BRNÄIÄ AND SUZANA RIMAC-BRNÄIÄ
Faculty of Food Technology and Biotechnology; University of Zagreb; Pierottijeva 6; Zagreb; Croatia
JOSE M. LORENZO
Centro TecnolĆ³gico de la Carne de Galicia, RĆŗa Galicia NĀŗ 4, Parque TecnolĆ³gico de Galicia, San CibrĆ”n das ViƱas, 32900 Ourense, Spain
FRANCISCO J . MARTI-QUIJAL AND FRANCISCO J . BARBA
Nutrition and Food Science Area, Preventive Medicine and Public Health, Food Science, Toxicology and Forensic Medicine Department, Faculty of Pharmacy, Universitat de ValĆØncia, Avda. Vicent AndrĆ©s EstellĆ©s, s/n, 46100 Burjassot, ValĆØncia, Spain
1 Introduction
The legislative framework developed in several countries around the world prioritizes recycling and recovery of waste and by-products to elimination. For instance, the European Directive 2006/12/EEC (Anonymous 2006) sets out the importance of encouraging the recovery of waste/by-products and the use of recycled materials in order to preserve natural resources. In this framework, Directive 2008/98/EC (Anonymous 2008) on waste lays down measures to protect the environment and human health by preventing or reducing overall impacts of resource use and improving the efficiency of such use.
The cultivation and processing of the products obtained entail the generation of waste that can be valued as by-products. In this sense, Lal (2005) defined the residue of a crop āas the part of the inedible plant that remains in the field after harvest.ā Some researchers also include as such the organic remains that are produced in the crop treatment plants, or those that are discarded after the management of the crop. Recently, Alexander et al. (2017) quantified the losses, inefficiencies, and waste in the global food system. These authors concluded that, due to cumulative losses, the proportion of global agricultural dry biomass consumed as food is just 6% (9.0% for energy and 7.6% for protein) and of harvest biomass is 24.8% (31.9% for energy and 27.8% for protein). The highest rates of loss are associated with livestock production, although the largest absolute losses of biomass occur prior to harvest. Losses of harvested crops were also found to be substantial, with 44.0% of crop dry matter (36.9% of energy and 50.1% of protein) lost prior to human consumption. On the other hand, about 38% of food waste is produced during food processing (Helkar, Sahoo, and Patil 2016).
According to the US Environmental Protection Agency (EPA), food waste represents the single largest type of waste entering landfills (Nishida 2014). A large amount of food waste and by-products, as well as their microbial decomposition, creates huge environmental, human health, economic, and social problems (Helkar, Sahoo, and Patil 2016; Koubaa et al. 2015; Mourad 2016; Parniakov et al. 2015; Putnik et al. 2017b). In addition, the large cost for waste treatment is an additional charge for the food manufacturers. However, wastes and by-products derived from agri-food industry contain large amounts of high-added-value compounds such as nutrients and bioactive compounds (e.g., vitamins, polyphenols, and glucosinolates/isothiocyanates), among others that have beneficial effects attributed, mainly, to their antioxidant power (Barba, Esteve, and FrĆgola 2014; Barba et al. 2016b; Deng et al. 2015; Granato, Nunes, and Barba 2017; Putnik et al. 2017a; RosellĆ³-Soto et al. 2016; VincekoviÄ et al. 2017). Food by-products have numerous applications in several industries such as pharmaceutical, biomedicine, cosmetic, paper industry, as well as human and animal nutrition, among others. In fact, a healthy trend in the food industry consists of converting the food wastes or by-products to functional food ingredients (Helkar, Sahoo, and Patil 2016).
In order to valorize the waste and by-products from different agri-food industries, it is important to evaluate first the amount produced, as well as the microbial load they present and the added value they can present from an economic point of view, especially due to their content in high-added-value compounds (Barba et al. 2015a, 2015b, 2016a; Barba and Orlien 2017; Putnik et al. 2017b).
Most of the wastes and by-products that have been selected in this book to extract high-added-value compounds, among other criteria, have been chosen for their remarkable production worldwide. Table 1.1 shows the global production data of some of the crops obtained from FAO in 2015. The waste generated by the crops can be estimated by multiplying the annual production by the values of residue-production-ratio (RPR) for each crop. The proportion between the harvested product and the waste can vary depending on a set of factors such as the variety of crop, the supply of water and nutrients during cultivation, the water content of the waste, the use of chemical growth regulators, environmental factors of each zone, harvested method, and so on (Abou Hussein and Sawan 2010; Eisentraut 2010; Singh 2015). The RPR depends on the crop and the approximate amount of waste generated worldwide for some of the waste generated.
Table 1.1 World production of crops in 2015
| MATRIX | WORLD 2015 PRODUCTION (MILLIONS TONS) | RPR1 | ESTIMATED RESIDUE PRODUCTION (MILLIONS TONS) |
| Cereals total | 2,795 | 1.5 Rice and wheat (Lal 2005) 2.0 Maize (Iye and Bilsborrow 2013) | 4,751 |
| Sweet potato | 103 | 0.25 (Iye and Bilsborrow 2013) | 26 |
| Olive oil | 3 | 1.5 (Eisentraut 2010) | ā |
| Nuts with nutshell | 3 | ā | ā |
| Wine | 29 | 0.25 (OIV 2015) | 7.25 |
| Oilseed (soya+rapeseed+sunflower+peanut+corn+sesame) | 98 | 1.5 (Eisentraut 2010) | 147 |
| Coffee green | 8.8 | 2.1 (Duku, Gu, and Hagan 2011) | 18.5 |
| Leaf vegetable | 287 | 1.25 (Eisentraut 2010) | 359 |
Most of the waste from crops is produced by cereals. Other important food by-products are pulses, fruits, vegetables, meat, dairy, marine, sugarcane, winery, and plantation waste. In particular, production and applications of waste and by-products originated from fruit and vegetable, grain proccesing, coffee, winery, marine (including fish and algae), meat, and dairy industries are reviewed in this book. Moreover, other by-products have been selected due to their importance at the local level such as tiger nuts (Cyperus esculentus). Given their high global annual production, to deliver insight into the current state of art and innovative extraction technologies to extract valuable products from food processing by-products is necessary (Koubaa et al. 2015; RosellĆ³-Soto et al. 2018a, 2018b).
Conventional methods of by-productsā disposal, animal feed, soil fertilizers, and/or biofuels do not provide the industry with the sufficient economic incentive to increase their competitiveness and address environmental problems, which is aggravated by legal restrictions. Traditionally, different techniques have been used for the recovery of bioactive compounds from waste and by-products of the agri-food industry, such as milling, extraction with solvents, etc. (Misra et al. 2015, 2017a; RosellĆ³-Soto et al. 2015b). However, this type of techniques, generally, uses a large amount of solvents, which in many cases can be toxic. Moreover, they also need long extraction times to obtain maximum performance, which supposes an additional operating cost. That is why research is necessary to find new alternative technologies to eliminate toxic solvents, reduce operating costs with the maximization of yields, and use techniques that are ecological, thus generating a great benefit for both industries and the society. Innovative extraction technologies are, in general, more āgreenā technologies than conventional ones for the extraction of bioactive compounds. As global waste production rates are expected to continue rising during the following decennium, the development and selection of sustainable waste management solutions become more and more interesting (Six et al. 2016).
Different classifications for waste and by-products from agri-food industries are available. Food by-products can be classified into the following six categories: (a) crop waste and residues; (b) fruit and vegetables by-products; (c) sugar, starch, and confectionary industry by-products; (d) oil industry by-products; (e) grain and legume by-products; and (f) distilleries and breweries by-products (Ajila et al. 2012). In the current book, waste and by-products from food industries will be categorized, based on Helkar et al. (2016) classification, as follows: (a) fruit and vegetable (including olive oil), (b) grain processing, (c) winery (includes also brewery), (d) marine, (e) meat, and (f) dairy industry.
