摘要:
为开发黑果枸杞汁加工新技术,采用超高压处理(300、400、500 MPa/10 min)和巴氏杀菌(75℃,15 min)处理,分析处理前后及贮藏期(4和37℃,40 d)的微生物、活性成分、关键内源酶及抗氧化活性等品质的变化。结果表明,200 MPa以上高压处理和巴氏杀菌均能有效杀灭酵母菌和霉菌,300 MPa以上高压处理能使菌落总数降低到1个对数以下;300 MPa高压处理能使过氧化物酶(Peroxidase,POD)活性减少17.81 U/mL,但不能使多酚氧化酶(Polyphenol oxidase,PPO)酶活性显著降低;400 MPa以上及巴氏杀菌均能使POD酶和PPO酶活性降低至0.5 U/mL;超高压处理分别为300、400、500 MPa条件下,总酚含量分别为87.10、87.11、86.92 mg/100 g、总多糖含量分别为61.54、61.04、60.97 mg/mL、花青素含量分别为2.62、2.56、2.58 mg/mL;超高压处理的黑果枸杞汁对DPPH自由基清除率分别为86.82%、87.40%、86.60%,均高于巴氏杀菌处理的82.17%;超高压处理组对亚铁离子的还原能力分别为15.74、16.15、15.95 μg/100 mL DW,处理后直至贮藏结束,高压处理各活性物质均高于巴氏处理。超高压处理在有效灭活微生物、钝化酶的同时,极大程度保护活性物质不被破坏并保证了黑果枸杞汁的抗氧化能力,使得黑果枸杞汁得到了良好的贮藏品质。
Abstract:
In order to develop new technologies for Lycium ruthenicum Murr juice processing,the juice of Lycium ruthenicum Murr treated by ultra-high pressure treatment(300,400,500 MPa/10 min) and pasteurization(75℃,15 min) were compared on microorganisms,main endogenous enzyme activities,active substances,and antioxidant capacity. The changes of these physicochemical indexes were also compared during storage period(4 and 37℃,40 d). The results showed that high-pressure treatment above 200 MPa and pasteurization could effectively kill yeasts and molds. High-pressure treatment above 300 MPa could reduce the total number of colonies to less than one logarithm. High-pressure treatment at 300 MPa could reduce POD enzyme activity to 17.81 U/mL,but could not significantly reduce PPO enzyme activity. Above 400 MPa and pasteurization could reduce POD enzyme and PPO enzyme activity to 0.5 U/mL. With the conditions of ultrahigh pressure treatment of 300,400,and 500 MPa,the contents of polyphenols were 87.10,87.11,86.92 mg/100 g,and total polysaccharide contents were 61.54,61.04,60.97 mg/mL,and anthocyanin contents were 2.62,2.56,2.58 mg/mL in juice under ultra-high pressure treatment. The DPPH free radical scavenging rates of Lycium ruthenicum Murr juice by ultra-high pressure treatment were 86.82%,87.40%and 86.60%,which were higher than 82.17%. The abilities reduced ferrous ions of Lycium ruthenicum Murr juice from ultra-high pressure treatment were 15.74,16.15,and 15.95 μg/100 mL DW,which were higher than those of pasteurization until the end of storage. The ultra-high pressure treatment could effectively inactivate microorganisms and inactivate enzymes,and protect the active substances from destruction to ensure the antioxidant capacity of Lycium ruthenicum Murr juice,so that the Lycium ruthenicum Murr juice would have a good storage quality.
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