## 5 Future Trends and Perspectives: Raisins and Currants Production within the Bio-Economy Era  
The majority of studies on raisins undertook the effect of processing on bioactive compounds but also the health benefits raisins exert, as previously demonstrated. However, raisins and particularly Greek currants were overlooked the past years, regardless the known and documented health benefits. The flourishing consumers' appeal for functional foods has induced an interest on traditional foods that were previously disregarded. As such, Greek currants have been lately implemented in numerous studies with a prosperous intention to reintegrate these products as part of an everyday balanced diet. Apart from the inclusion of currants in well-established bread and bakery products, to further enhance the nutritional value, currants could serve as a carrier matrix for the fortification of foods with probiotic strains, in a similar approach to previous studies reporting the inclusion of probiotics on dried fruit [88; 89]. The composition of currants in fructooligosaccharides, a well-established prebiotic compound, along with probioticcould entail a potential symbiotic effect [90]. Subsequent studies could be directed on investigating also the viability through the passage of the gastrointestinal transit. Likewise, the viability of bacteria versus storage time and temperature could be also implemented. On top of that, textural and sensorial characterization will entail a crucial factor to be determined in order to coincide with consumers' acceptance. Increased demand for currants will ultimately result in a proportional upturn of waste streams. Currant processing wastewater is mainly composed of sugars, glucose, and fructose, including lower concentrations of nitrogen compounds, lipids, minerals, organic acids, tannins, and pectins [91]. For instance, hot water blanching of currants is accompanied by significant losses in nutritional compounds along with the management of wastewater streams [18]. So far, wastewater treatment of currant-finishing facilities included chemical and physical processes (coagulation, acidification, evapotranspiration, and anaerobic digestion) to reduce chemical oxygen demand (COD) and mitigate the polluting effect, thus enabling reutilization for irrigation [91]. Biological treatment methods were recently reported by [PERSON] et al. [92], where raisin and winery effluents were utilized for the fermentative production of biomass and lipids. The synthesized lipids from cyanobacteria/microalgae consortia, containing saturated and mono-unsaturated fatty acids, were also evaluated as feedstock for biodiesel production. In a following study, winery-raisin wastewater was also used as substrate in mixed microbial cultures using a support matrix as an attached growth system, to produce biomass, lipids, and biodiesel [93]. The authors demonstrated an intracellular lipid content up to 23.2%, suggesting also the suitability for biodiesel production and correspondingly further optimization of the process for industrial-scale implementation. Inevitably, currant processing facilities will be required to undertake waste stream management schemes to conform with the context of bio-economy. Development of integrated biorefinery concepts to generate value-added products could provide the potential to resolve waste effluent treatment (Figure 3). Several approaches have implemented the utilization of agro-industrial and food residues as onset material to produce multiple products [94]. A more targeted approach for Zante currant side streams valorization as renewable feedstock within a biorefinery scenario was presented by [PERSON] et al. [57]. In this case, rejected Zante currants from the processing stage, were employed to yield a sugar-rich extract and a phenolic fraction. Analysis of phenolic compounds exhibited moderate antioxidant activity.