不同超高静压处理及贮藏过程中杨梅果汁微生物多样性变化

Changes in Microbial Diversity in Bayberry Juice under Different High Hydrostatic Pressure Treatments and Storage Conditions

摘要:

为探讨杨梅果汁合适的超高静压（High Hydrostatic Pressure, HHP）加工与贮藏条件，该研究以非浓缩还原（Not from concentrate, NFC）杨梅果汁为试验对象，对其进行HHP处理（500 MPa/20 min、500 MPa/30 min、600 MPa/10 min、600 MPa/20 min），再分别经过4、25、37 ℃贮存后，采用16S rDNA高通量测序技术对杨梅果汁中微生物多样性进行分析。结果表明：NFC杨梅果汁中的细菌门主要为厚壁菌门（Firmicutes），随后为放线菌门（Actinobacteria）和变形菌门（Proteobacteria）。主要菌属为双歧杆菌属（Bifidobacterium）、肠球菌属（Enterococcus）和肠杆菌属（Enterobacter）；经25 ℃和37 ℃贮藏7 d后，对照组以醋杆菌属（Acetobacter）为主，HHP 组以葡糖杆菌属（Gluconobacter）为主；4 ℃贮藏28 d，葡糖杆菌属占据绝对优势（86.62%~98.42%）。将600 MPa/20 min 杨梅汁经结合隔氧贮藏7 d（37 ℃）后，有效降低了葡糖杆菌属的丰度，并经货架期加速试验预测其在20 ℃的货架期为133 d。该研究为HHP加工新技术的应用以及NFC 果汁的安全性控制提供了相应理论依据。

Abstract:

To explore the suitable high hydrostatic pressure (HHP) processing and storage conditions for bayberry juice, notfrom-concentrate (NFC) bayberry juice was subjected to HHP treatments (500 MPa/20 min, 500 MPa/30 min, 600 MPa/10 min, and 600 MPa/20 min) and temperatures (4, 25, and 37 ℃). The microbial diversity of the bayberry juice was analyzed using 16S rDNA high-throughput sequencing. Results revealed that NFC bayberry juice is dominated by Firmicutes, followed by Actinobacteria and Proteobacteria. Bifidobacterium, enterococcus, and Enterobacter were the dominant genera. After incubation at 25 ℃ or 37 ℃ for seven days, acetobacter became dominant in the control group, while Gluconobacter became dominant in the HHP group. After storage at 4 ℃ for 28 days, gluconobacter became the dominant genus, accounting for 86.62%~98.42% of the total population. After storing the HHP-treated (600 MPa/20 min) bayberry juice at 37 ℃ for seven days in an anaerobic conditions, the gluconobacter abundance was significantly reduced. The commercial shelf-life of bayberry juice at 20 ℃ was expected to be 133 days, based on the shelf-life acceleration test. This study provides a theoretical basis for further application of HHP and food safety control in NFC juices.