Lim Sang-Bin
Department of Food Bioengineering, Jeju National University, Jeju 63243, Korea.
Foods. 2021 Dec 22;11(1):18. doi: 10.3390/foods11010018.
Immature pomace (ICUP) was hydrolyzed under organic acid-catalyzed, subcritical water (SW) conditions to produce flavonoid monoglucosides (hesperetin-7--glycoside and prunin) and aglycons (hesperetin and naringenin) with high biological activities. The results of single-factor experiments showed that with 8 h of hydrolysis and an increasing citric acid concentration, the yield of flavonoid monoglucosides (hesperetin-7--glycoside and prunin) increased from 0 to 7% citric acid. Afterward, the hesperetin-7--glycoside yield remained constant (from 7 to 19% citric acid) while the pruning yield decreased with 19% of citric acid, whereas the aglycon yield increased continuously. In response surface methodology analysis, a citric acid concentration and hydrolysis duration of 13.34% and 7.94 h were predicted to produce the highest monoglucoside yield of 15.41 mg/g, while 18.48% citric acid and a 9.65 h hydrolysis duration produced the highest aglycon yield of 10.00 mg/g. The inhibitory activities of the SW hydrolysates against pancreatic lipase (PL) and xanthine oxidase (XO) were greatly affected by citric acid concentration and hydrolysis duration, respectively. PL and α-glucosidase inhibition rates of 88.2% and 62.7%, respectively, were achieved with 18.48% citric acid and an 8 h hydrolysis duration, compared to 72.8% for XO with 16% citric acid and 12 h of hydrolysis. This study confirms the potential of citric acid-catalyzed SW hydrolysis of ICUP for producing flavonoid monoglucosides and aglycons with enhanced enzyme inhibitory activities.
未成熟果渣（ICUP）在有机酸催化的亚临界水（SW）条件下进行水解，以生产具有高生物活性的黄酮类单糖苷（橙皮素-7-O-糖苷和樱草糖苷）和苷元（橙皮素和柚皮素）。单因素实验结果表明，水解8小时且柠檬酸浓度增加时，黄酮类单糖苷（橙皮素-7-O-糖苷和樱草糖苷）的产率从0增加到7%柠檬酸。此后，橙皮素-7-O-糖苷产率保持恒定（从7%到19%柠檬酸），而樱草糖苷产率在19%柠檬酸时下降，而苷元产率持续增加。在响应面法分析中，预测柠檬酸浓度为13.34%且水解时间为7.94小时时，单糖苷产率最高，为15.41mg/g，而柠檬酸浓度为18.48%且水解时间为9.65小时时，苷元产率最高，为10.00mg/g。SW水解产物对胰脂肪酶（PL）和黄嘌呤氧化酶（XO）的抑制活性分别受柠檬酸浓度和水解时间的极大影响。在柠檬酸浓度为18.48%且水解时间为8小时时，PL和α-葡萄糖苷酶的抑制率分别达到88.2%和62.7%，相比之下，XO在柠檬酸浓度为16%且水解12小时时的抑制率为72.8%。本研究证实了柠檬酸催化ICUP的SW水解用于生产具有增强酶抑制活性的黄酮类单糖苷和苷元的潜力。
