超高压处理对鲜切莲藕品质及其贮藏性的影响
Effects of ultra high hydrostatic treatment on the quality of fresh-cut lotus roots during storage

以鲜切莲藕为载体，研究超高压处理对鲜切莲藕的Vc、可溶性固形物、菌落总数、质构、多酚氧化酶（polyphenol oxidase,PPO）活性等各项品质指标及其在贮藏过程中的影响。结果表明：随着处理压力的增大和保压时间的延长，莲藕中可溶性固形物、总酚含量基本保持不变（P＞0.05）；还原型Vc、PPO的活性、脆度均呈下降趋势（P<0.05）。压力对微生物的影响效果比较显著（P<0.05）;随着压力的增加,灭菌效果越好,但延长保压时间,杀菌效果并没有进一步提升。在贮藏期间，与未经超高压处理的对照组相比，超高压处理后的鲜切莲藕Vc损失程度较小，可溶性固形物损失逐渐增大,总酚含量逐渐降低,而PPO活性变化趋势则是先降低后升高，再逐渐降低;并且随着贮藏时间的延长,莲藕的脆度值呈下降趋势，L*值下降，a*值上升，总体色差增大。整个贮藏期间500 MPa处理的莲藕色差变化最小。总菌落数随贮藏时间的增加而不断增加，但总体来说压力越大，微生物增长速度越慢。对超高压处理后莲藕细胞结构进行显微观察，发现高压处理可以破坏细胞结构，并且压力越大对细胞结构的破坏作用越明显。
Fresh-cut lotus roots were used to study the effects of ultra high hydrostatic treatments on the quality of lotus roots during storage.With the increase of pressure and holding time of extending,soluble solid and total phenol had little changes.The content of ascorbic acid,the activity of PPO and the frangibility of lotus roots decreased significantly (P<0.05).The high hydrostatic pressure treatment significantly inhibited the microbial growth (P<0.05).The sterilization effect was not increased with the prolonging of holding time,indicating that the instant pressurization and instantaneous unloading process played an important role in ultra high pressure sterilization.Further studies of ultra high pressure treatment on fresh-cut lotus root showed that the loss of Vc under UHP treatment was lower than that of the control but the soluble solids loss increased gradually during storage.The color of lotus root changed little.The high hydrostatic pressure treatment inhibited the PPO activity and the microbial growth.It was clearly demonstrated under the microscope that the high pressure damaged the cell structure of lotus root.