Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Block S3, Level 6, Science Drive 4, Singapore 117543, Republic of Singapore.
Food Microbiol. 2011 May;28(3):377-83. doi: 10.1016/j.fm.2010.09.010. Epub 2010 Oct 1.
The objective of this study was to evaluate the efficacy of supercritical carbon dioxide (SCCO(2)) for inactivating Lactobacillus plantarum in apple cider using a continuous system with a gas-liquid metal contactor. Pasteurized apple cider without preservatives was inoculated with L. plantarum and processed using a SCCO(2) system at a CO(2) concentration range of 0-12% (g CO(2)/100g product), outlet temperatures of 34, 38, and 42 °C, a system pressure of 7.6 MPa, and a flow rate of 1 L/min. Processing with SCCO(2) significantly (P<0.05) enhanced inactivation of L. plantarum in apple cider, resulting in a 5 log reduction with 8% CO(2) at 42 °C. The response surface model indicated that both CO(2) concentration and temperature contributed to the microbial inactivation. The extent of sublethal injury in surviving cells in processed apple cider increased as CO(2) concentration and processing temperature increased, however the percent injury dramatically decreased during SCCO(2) processing at 42 °C. Structural damage in cell membranes after SCCO(2) processing was observed by SEM. Refrigeration (4 °C) after SCCO(2) processing effectively inhibited the re-growth of surviving L. plantarum during storage for 28 days. Thus this study suggests that SCCO(2) processing is effective in eliminating L. plantarum and could be applicable for nonthermal pasteurization of apple cider.
本研究旨在评估超临界二氧化碳（SCCO₂）在使用气液金属接触器的连续系统中对苹果 cider 中植物乳杆菌的灭活效果。未经防腐剂处理的巴氏杀菌苹果 cider 接种植物乳杆菌，然后使用 SCCO₂ 系统在 CO₂浓度范围为 0-12%（g CO₂/100g 产品）、出口温度为 34、38 和 42°C、系统压力为 7.6 MPa 和流速为 1 L/min 的条件下进行处理。SCCO₂ 处理显著（P<0.05）增强了苹果 cider 中植物乳杆菌的灭活效果，在 42°C 下用 8% CO₂可实现 5 个对数减少。响应面模型表明，CO₂浓度和温度都对微生物失活有贡献。在加工的苹果 cider 中，存活细胞的亚致死损伤程度随 CO₂浓度和处理温度的升高而增加，但在 42°C 下进行 SCCO₂ 处理时，损伤百分比急剧下降。SCCO₂ 处理后通过 SEM 观察到细胞膜的结构损伤。SCCO₂ 处理后冷藏（4°C）可有效抑制存活的植物乳杆菌在 28 天储存期间的再生长。因此，本研究表明 SCCO₂ 处理有效消除了植物乳杆菌，可适用于苹果 cider 的非热巴氏杀菌。
