射频热水联合漂烫对鲜切西兰花过氧化物酶活性的影响

Effects of combined radio frequency and hot water blanching on peroxidase activity of fresh cut broccoli

中文关键词:  西兰花  钝化  射频  漂烫

英文关键词:broccoli  deactivation  radio frequency  blanching

中文摘要:

      目的 研究射频热水联合漂烫对鲜切西兰花过氧化物酶(peroxidase, POD)活性的影响。方法 采用6 kW, 27.12 MHz自由振荡式平行极板射频系统, 对500 g不同切割尺寸(50、30和20 mm)的西兰花在不同极板间距(90、95、100、105和110 mm)和不同漂烫目标温度(70、80、90°C)下进行射频加热, 测定射频漂烫速率和均匀性。以愈创木酚、过氧化氢为底物, 通过分光光度计法, 对单独射频、单独热水、射频热水联合处理后西兰花POD相对酶活进行测定。结果 西兰花射频加热后的POD相对酶活是射频加热温度和持续时间的双重作用, 针对中间尺寸西兰花, 与单独热水漂烫(90°C, 120 s)相比, 射频(70°C, 59 s)和热水(90°C, 10 s)联合可将漂烫时间缩短至69 s, 漂烫时间减少了42.5%, 能量效率提高了110%。此时的最佳漂烫条件为: 极板间距90 mm, 西兰花尺寸30 mm, 射频漂烫目标温度70°C, 热水温度90°C。结论 射频热水联合是一种高效、高品质的漂烫处理方法, 能够有效降低西兰花中过氧化物酶活性且获得最佳的能量利用效率。

英文摘要:

      Objective To study the effect of radio frequency combined with hot water blanching on peroxidase (POD) activity in fresh-cut broccoli. Methods A 6 kW, 27.12 MHz free-oscillating parallel plate radio frequency system was used to heat 500 g of broccoli with different cutting sizes (50, 30 and 20 mm) at different electrode gap (90, 95, 100, 105 and 110 mm) and different blanching target temperatures (70, 80, 90°C). Radio frequency blanching rate and uniformity were measured. Using guaiacol and hydrogen peroxide as substrates, POD relative enzyme activity of broccoli treated with radio frequency alone, hot water alone, radio frequency combined with hot water was determined by spectrophotometer. Results The POD relative enzyme activity of broccoli after radio frequency heating was the dual effect of radio frequency heating temperature and duration. For mid-size broccoli, the combination of radio frequency (70°C, 59 s) and hot water (90°C, 10 s) could reduce blanching time to 69 s, reduce blanching time by 42.5% and increase energy efficiency by 110% compared to hot water blanching alone (90°C, 120 s). At this time, the best blanching conditions were: electrode gap of 90 mm, broccoli size of 30 mm, radio frequency blanching target temperature of 70°C and hot water temperature of 90°C. Conclusion The combination of radio frequency and hot water is an efficient, high-quality blanching method that can effectively reduce the POD activity in broccoli and obtain the best energy use efficiency.