Micro-encapsulation exhibits better protection than nano-encapsulation on phenolics before and after in vitro digestion

In this study, micro-capsules (by complex coacervation) and nano-capsules (by liposomal encapsulation) containing phenolic extracts from jujube peel (PEJP) were compared in terms of changes in encapsulation efficiency, phenolic and anthocyanin content and antioxidant, angiotensin converting-I enzyme (ACE) inhibitory and alpha-amylase inhibitory activities before and after in vitro digestion. According to the results, micro-capsules were prepared with a biopolymer ratio of 0.125:1:1 (PEJP: WPI: GA) at pH 3.4, while nano-capsules were obtained using 1% lecithin and 0.4% chitosan at pH 3.4. Nano-capsules had higher encapsulation efficiency (74.27%) than micro-capsules (67.34%). In contrast, total phenolic content of PEJP was preserved better in micro-capsules before and after in vitro digestion compared with nano-capsules. The highest total monomeric anthocyanin content remained in the undigested micro-capsules and in the digested nano-capsules. Micro-capsules exhibited a stronger antioxidant activity than those of nano-capsules with PEJP with both DPPH and CUPRAC assays. After in vitro intestinal digestion, micro-capsules with PEJP exhibited the highest ACE inhibitory activity (80.00 +/- 2.50%) and alpha-amylase inhibitory (48.31 +/- 0.84%) activity. Considering all these results, micro-capsules protected phenolics better than nano-capsules. The stability of phenolics based foods can be protected by microencapsulation. Also, microencapsulants including phenolics can be added to cosmetic and food supplements.