The inactivation kinetics of β-glucosidase in blackberry were investigated at high hydrostatic pressure (300-600 MPa) combined with moderate temperature (35-55°C). Analysis of the obtained kinetic data revealed a dual-effect of combined pressure-temperature inactivation: the first one, designated as an instantaneous pressure kill value (IPK), which depended on temperatures and pressures, but was independent of treatment time; and the second one, a labile and stable fraction of β-glucosidase from blackberry are present and the inactivation kinetics of β-glucosidase by high hydrostatic pressure combined with temperatures are adequately described by the two-fraction model. The kinetic rate constants K L and K S of labile and stable fractions are 2.777 and 0.047 min -1, and the decimal reduction times D L and D S are 0.83 and 49.1 min at 400 MPa and 55°C. T Z representing the needs of temperature increase for a 90% reduction of the D value and the activation energy E a of the labile fraction at 400 MPa are 23.36°C and 81.95 kJ/mol, p Z representing the needs of pressure increase for a 90% reduction of the D value and the activation volume V a at 45°C are 1111 MPa and -5.02 cm 3/mol.

采用固相微萃取与气相色谱质谱仪（GC-MS）联用检测,对超高压处理前、后黑莓清汁香气成分进行分析和感官评价。结果表明:经超高压处理的黑莓清汁香气种类与原汁相同,但不同成分的含量略有变化,300 MPa处理10 min的黑莓清汁醇类、酯类含量减少了4.8%和11.1%,醛类、酮类含量增加了12.06%和14.59%;400 MPa处理10 min后,其内的醇类、酯类、醛类含量增加4.9%、26.86%和9.9%;而200、500和600 MPa处理10 min的黑莓清汁醇类、酯类、醛类含量均无显著变化。感官评定表明,400 MPa处理10 min能较好地保留黑莓清汁典型浓郁的香气,且与GC-MS检测分析结果一致。

The effects of high pressure processing(HPP) at 300~600 MPa for 15 min on organic acids and VC in blackberry(Rubus Hull.) juice were detected by using reversed-phase high performance liquid chromatograp method and 2,4-Dinitrophenylhydrazine colorimetry method respectively.Their synergistic antioxidant capacities were also evaluated.In blackberry juice,the dominant acid was L-malic acid,which constituted 87.98% of total acids.While α-ketoglutaric acid,acetic acid,citric acid,and butanedioic acid were detected in low amounts.After application of pressure,L-malic acid and butanedioic acid were significantly changed(P<0.05).However,no significant changes in other organic acids(P>0.05).L-malic acid in juice decreased by 12.2% after 300 MPa processing for 15 min,while increased by 8.53%,6.08% and 22.35% respectively at 400~600 MPa processing for 15min.Compared with the control juice,the contents of VC were well retained and ranged from 90.10% to 97.92% at 300~600 MPa.L-malic acid enhanced the scavenging activity of VC on DPPH· with its concentration increasing,which indicated that L-malic acid synergistically enhanced the antioxidant capacity of VC.

The effect of high pressure processing(HPP) on levels of total phenolic,flavonoid content and the in vitro antioxidant activity of soymilk was studied.The antioxidant activity of soymilk was evaluated by DPPH free radical scavenging activity and ferric reducing antioxidant power(FRAP).Results showed that the total phenolic content had no significant differences after 200 MPa treatment(P0.05),the significant increases were observed after 300,400,500 MPa(P0.05) treatments,whereas thermal treatment significantly reduced the level(P0.05).In addition,the flavonoid content,DPPH and FRAP values were significantly higher than that of unprocessed soymilk after 400,500 MPa treatments and thermal treatment.The optimal treatment condition of soymilk was 400 MPa,10 min and its total phenolic and flavonoid content values were 2.51 mg·g-1 and 0.48 mg·g-1,respectively,the DPPH free radical scavenging activity was 79.6% and the FRAP value was 0.83.

The effects of high pressure processing（HPP）（200～600 MPa for 10 min） on the changes of sensory quality,physicochemical properties and nutritional quality of carrot juice were studied.The results showed that：compared with the control samples,the colors,total soluble solids,total sugars,α-and β-carotene contents had no significant differences after HPP（P﹥0.05）,The total antioxidant capacity reduced significantly after 400 MPa processing,while increased a lot after 600 MPa processing.In addition,by HPP,the pH of carrot juice was decreased,total acid content increased,sedimental stability was improved,all of which were changed significantly（P0.05）.Based on an overall consideration of various experimental results,carrot juice had the best quality after 600 MPa processing.Therefore,the HPP can maintain a fairly good quality and nutritional value of carrot juice,which can achieve the purpose of maintaining nutritional quality and extending its shelf life.