## 3 Results and Discussion
Analyzing the two different cultivars, there is a significant difference between AK_D and W_D, with a higher value for Akko. On the contrary, no significant differences in TPC were observed between the cultivars when the extraction was performed by PUAE. As regards RSA, no significant differences were observed by ANOVA in Akko and Wonderful cultivars extracted both by decoction and PUAE, although the statistical significance was very low (Table 2). Some previous studies, which considered aqueous extracts of pomegranate peels starting from different cultivars, showed an extraction efficiency, expressed as TPC, lower than that obtained in the present work; for example, [PERSON] et al. 2014 [41] reported a TPC equal to 16.343 mg GAE/g for aqueous extracts obtained from similarly oven-dried peels, which is more than 10 times less than those reported in Figure 1. [PERSON] et al. 2019 [24] described different 'green' extraction methods using just water as a solvent to efficiently extract the bioactive fraction of pomegranate peels. From a comparison of different aqueous extraction methods applied to pomegranate peels, such as ultrasound (UAE), infrared, pulsed electric fields, and high-voltage electrical discharges (HVED), HVED-assisted extraction, applied for 7 min., yielded a maximal concentration of phenolics equal to 46 mg GAE/g DW. After the same period, the UAE method yielded phenolic recovery equal to 14.5 mg of GAE/g DW, which is approximately 10-16 times lower than the TPCs of those reported in Figure 1. Recently, [PERSON] et al. 2019 [42], exploiting the action of ultrasound and microwave to extract the phenolic compounds from pomegranate peels, described TPCs equal to 119.82 mg GAE/g dry peel and 199.4 mg GAE/g dry peel, respectively, which are more in accordance with the values described in this study (148-237 mg GAE/g DW). Figure 2 reports the free EA and ET amounts of the peel aqueous extracts (D and PUAE) belonging to the two different cultivars investigated. Figure 1: TPC and RSA of Akko and Wonderful pomegranate peel aqueous extracts obtained by the traditional (D) and innovative extraction technique (PUAE). Bars show mean values and SE of the replicated data. Free EA and ET contents were not correlated. In particular, for both cultivars, the decoction (AK_D and WO_D) showed higher EA and lower ET contents compared to the PUAE extracts (AK_PUAE and WO_PUAE). The PUAE extract, according to several other green strategies reported in the literature [42; 43; 44], confirms its superiority in terms of ET recovery, even if the simplest decoction is endowed with a higher free EA content, probably due to the highest boiling temperature, which allows the partial hydrolysis of ETs with the consequent release of the common aglycone (EA) and some sugar moieties [36]. The aim of this investigation was the comparison between the innovative PUAE and the traditional decoction. For this reason, the same experimental conditions (extraction time, liquid/solid ratio, extraction solvent) were maintained for both of the extraction strategies with the exception of the temperature, which was the only variable that changed (PUAE \(<\) 65 \({}^{\circ}\)C and D \(=\) 100 \({}^{\circ}\)C). ETs are stable in acidic conditions (pH \(=\) 2-4), which is their natural condition; nevertheless, they rapidly degrade in neutral and mildly basic media, especially at higher temperatures [36]. In acidic conditions, as in the pomergnate extracts, ETs show high stability in the range of temperature 20-60 \({}^{\circ}\)C but at 80 \({}^{\circ}\)C they gradually degrade [36]. One-way ANOVA, analyzing the mean differences of the free EA content, showed significant differences (\(p<\) 0.05) only between AK_D and WO_D.