采用反相高效液相色谱法、2,4-二硝基苯肼法对300～600 MPa处理15 min的黑莓汁中有机酸、VC进行检测分析,并采用DPPH.法对其协同抗氧化性进行评价。结果表明:黑莓汁有机酸主要是L-苹果酸,占总酸的87.98%,并含有少量的α-酮戊二酸、醋酸、柠檬酸和琥珀酸等;超高压处理对黑莓汁中琥珀酸和L-苹果酸的影响显著(P<0.05),对其他酸作用不显著(P>0.05)。经300 MPa、15 min处理,黑莓汁中L-苹果酸含量减少12.2%,400、500和600 MPa处理15min后,其L-苹果酸含量分别增加8.53%、6.08%和22.35%;超高压黑莓汁中VC的保留率在90.10%～97.92%;随着L-苹果酸浓度的增加,其协同VC清除DPPH自由基能力显著增强(P<0.05),表明L-苹果酸可协同VC增加其抗氧化性。

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.