%0 Journal Article %A ZHANG Yanrong %A FAN Hongxiu %A LIU Hongcheng %A DONG Xin %T Preparation and Identification of Cyclo (His-Pro) Precursors from Corn Protein %D 2016 %R 10.7506/spkx1002-6630-201622008 %J FOOD SCIENCE %P 52-59 %V 37 %N 22 %X The value-added use of corn protein for production of the cyclo (His-Pro) precursors histidyl-proline (His-Pro) and prolyl-histidine (Pro-His) was investigated. The extracted γ-zein was hydrolyzed with single proteases (alcalase, protamex, flavourzyme and papain) and two proteases in sequence, respectively. The hydrolysate prepared with alcalase and flavourzyme in sequence exhibited the highest content of cyclo (His-Pro) precursors. Response surface methodology and an orthogonal array design L16 (45) were applied to optimize the hydrolysis conditions. The optimum conditions for alcalase hydrolysis were as follows: substrate concentration of 32 mg/mL, enzyme/substrate (E/S) ratio of 12 100 U/g and hydrolysis time of 6.5 h, while the optimum conditions for flavourzyme hydrolysis were as follows: E/S ratio of 17 000 U/g, pH of 7.5, hydrolysis temperature of 55 ℃ and hydrolysis time of 6 h. Identification and quantification of cyclo (His-Pro) precursors in the hydrolysate were achieved by ultraperformance liquid chromatography (UPLC) and electrospray ionizationmass spectrometry (ESI-MS). The results showed that the hydrolysate contained a high content of Pro-His dipeptide (6.88 mg/g). %U https://www.spkx.net.cn/EN/10.7506/spkx1002-6630-201622008