Effects of high-pressure homogenization, thermal processing, and milk matrix on the in vitro bioaccessibility of phenolic compounds in pomelo and kiwi juices

We investigated the effects of high-pressure homogenization processing (HPHP), thermal treatment (TT), and milk matrix (soy, skimmed, or whole milk) on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) scavenging activity and in vitro bioaccessibility of total and individual phenolics in pomelo juice (PJ) and kiwi juice (KJ). HPHP and TT resulted in an increase of 10.6–17.5% in the phenolic contents of KJ and PJ but diminished phenolic bioaccessibility from 1.3% to 46.8%. Addition of milk matrix effectively enhanced phenolic bioaccessibility in KJ and PJ from 21.6% to 37.8% and 60.1% to 63.3%, respectively, except that addition of soy milk reduced total phenolic (TP) bioaccessibility by 14.9% in PJ. Skimmed milk improved TP bioaccessibility in KJ to a greater extent than did soy or whole milk, and whole milk effectively enhanced bioaccessibility in PJ. Our results suggest that the bioaccessibility of phenolics in fruit can be improved by regulating processing conditions and food matrices.