Effects of Heat Treatment on Protein Changes and Antioxidant Activity of Coconut
The changes of coconut protein after heat treatment were studied. The influence factors were heating temperature, heating time and different microwave time. The evaluation indexes were liquid chromatography of coconut protein(RP-HPLC), electrophoresis(SDS-PAGE), MALDI-TOF-MS, protein concentration change and antioxidant activity (Nitroso R salt-CO3 + color fading method). The microwave treatment of RP-HPLC and SDS-PAGE spectra began to change at 9 seconds. Heat treatment at 85, 100 and 120 °C began to change after 20 minutes. The change may be due to the high temperature which caused the protein to polymerize, recombine and decompose. The results of MALDI-TOF-MS showed that compared with unheated proteins, three proteins were identified, which were 11S globulin subtype 1 [coconut], glutenin [oil palm] and pea globulin-like antimicrobial peptide 2-1, some [oil palm], indicating that some of the heated coconut proteins were decomposed into other proteins or peptide segments. When the heat treatment of coconut protein had the smallest effect on oxidation resistance, the treatment conditions were 85°C, 20 minutes, and when the microwave treatment time was 7 seconds, the clearance rate of coconut protein solution toOH was the best, IC50 was 1.074. This study provides a theoretical basis for promoting the development and utilization of coconut products.