## 4 Discussion  
In this context, the results from this study support the possibility to propose an efficient green procedure, using water (PW) or ethanol aqueous solution (10%) (PE) to recover value added compounds from potato peels in order to formulate food-grade additives useful to replace or at least reduce synthetic preservatives in freshly stored vegetables.  
While the final validation of the proposed method requires the comparison of the results obtained with those derived from other known extraction techniques (i.e., other solvent composition, ultrasound assisted, etc.), the results showed appear encouraging, and the cryomaceration of potato peels appears as a very efficient as well as easy way to realize the pre-treatment phase, thus promoting the extraction of bioactive compounds from these wastes.  
The novel formulations (PE and PW) were particularly rich in phenol compounds. As a consequence of their interesting antioxidant power, PE and PW exhibited a good activity in keeping the quality of fresh-cut apple, regardless of the solvent utilized during extraction. In particular, a significant anti-browning effect as well as a slowing down of softening of fruits were observed.  
Although this study is the first step in this direction, the potato peel extracts could represent potential novel natural additives of interest with the possibility of replacing or at least reducing synthetic preservatives in post-harvest treatments for the production of MP fruits. Furthermore, the employment of potato peels proposed in this study may contribute to their valorization as a promising strategy to manage the environmental and economic problems caused by the increasing amount of potato waste and residues from food-processing industries.  
Figure 4: Flesh firmness expressed in kilogram-force (kg/0.5 cm\({}^{2}\)) of fresh-cut apples treated with different preservative media (sample codes are described in Table 1). Data are referred to storage at \(20\pm 1\)\({}^{\circ}\)C (2 and 4 h) and \(4\pm 1\)\({}^{\circ}\)C (1 and 3 days). Values are means \(\pm\) SE and different letters indicate significant statistical difference (\(p\leq 0.05\)).  
In the present study our attention has been focused on the overall effect showed by different antioxidant compounds present in the potato extract as a whole [63]. Future experimental investigations are needed to estimate the suitability as well as the economic feasibility of the replacement of unsafe chemicals with potato extracts in extending fresh-cut fruit. In particular, the antimicrobial effects, the sensory impact, and a more detailed chemical characterization of PE and PW need to be performed.  
[PERSON], [PERSON], and [PERSON] conceived and designed the experiments; [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] performed the experiments; [PERSON] analyzed the data and made graphs; [PERSON], [PERSON], [PERSON], and [PERSON] wrote the paper. [PERSON] coordinated the project.  
This work was supported by the project \"I residui della trasformazione dell'ordo-frutta: da'scarto' a 'risorsa' per il recupero di composti fitochimici naturali\" from the MiPAAFT (Italian Ministry \"Politiche Agricole Alimentari, Forestali e del Turismo\").  
The authors declare no conflict of interest.