轻微加工大黄鱼特定腐败菌生长/非生长调控及响应机制研究

The original nutrition, texture and flavor of lightly salted Pseudosciaena crocea can be retained better by lightly preserved means, to meet consumers’ demands for natural, nutritious, ready-to-use and safety seafood .Since high-strength preserved ways to inhibit microbial growth can’t be adopted, the freshness decreases and safety risks rise. That is a critical point to investigate the indefiniteness of targeted microorganisms, lack of digital assessments, confusion of action mechanisms to solve the contradiction between light process of fish products and the increasing of safety risks. Lightly preserved Pseudosciaena crocea including salt-cured and semi-moisture fish will be chosen as raw materials in this project. On the basis of identifying specific spoilage organisms(SSOs) including Proteus vulgaris and Vibrio alginolyticus etc. in lightly preserved Pseudosciaena crocea, the project optimizes the major, sensitive stress factors(temperature, salinity, pH, water activity, organic acids and natural preservative,etc.）and their action domains, regulates their growth/no growth activities,digitally evaluates their regulation effects by growth/no-growth model, validates and modifies the growth/no growth models in fish, and explores the physiological and energy mechanisms of SSOs from growth to no-growth conditions. The project will provide scientific basis for digitally elucidating the regulation effects of growth/no growth for targeted microorganisms isolated from aquatic products under multiple and mild regulation factors, theoretical supports for response mechanism of objective conversion from growth to non-growth of targeted microorganisms, meanwhile the reference for optimizing traditional fish products, developing new fish products, and realizing the technological innovations of safety risk assessment of fish products.

轻腌大黄鱼采用轻微化加工，能较好保持原有营养、质地和风味等，符合人们追求天然、营养、即用和安全的消费需求。由于不能采用高强度控菌手段，鲜度下降和安全风险随之上升。要解决加工轻微化与安全风险增加之间的矛盾，需针对水产品靶向微生物模糊，调控缺乏数字化评估及作用机制不清等关键问题进行研究。本项目拟选取轻微加工（腌渍和半干）大黄鱼为对象，在前期确定轻微加工大黄鱼特定腐败菌（普通变形杆菌和溶藻弧菌等）的基础上，确定特定腐败菌胁迫因子（如温度、盐分、pH、Aw、有机酸和保鲜剂等）和作用范围，采用生长/非生长模型评估调控效应，并在真实食品中进行验证和修正，探究胁迫因子作用下由生长向非生长转化的生理学和能量学响应机制。本项目的实施将从数字化层面评估多重温和胁迫因子作用下靶向微生物生长/非生长的调控效应，解析生长/非生长之间转化的响应机制，以及为传统水产品优化升级、新产品和风险评估新技术提供支撑。

轻腌大黄鱼采用轻微化加工，能较好保持原有营养、质地和风味。本课题开展了轻微加工大黄鱼SSO（普通变形杆菌和蜂房哈弗尼菌）腐败特性及相互效应、生长/非生长调控、能量学响应机制，评价验证等研究。表明：①两种菌均具有较强腐败能力，生物被膜产生影响腐败能力，腐败能力比较为复合菌>普通变形杆菌>蜂房哈夫尼菌，两菌共存加速腐败进程；②确定了SSO胁迫因子（如温度、盐分、Aw和乙醇等）和保鲜剂（茶多酚、壳聚糖、Nisin等）作用范围，采用了生长动力学及生长/非生长模型评估调控及协效应。随茶多酚、NaCl浓度增大及pH下降，两菌µmax减小，λ增加，NaCl和茶多酚抑菌效应极显著，茶多酚和pH存在交互增强效应；壳聚糖在亚抑菌质量浓度时，Nisin浓度越高，协同抑制作用越强，壳聚糖62.5μg/mL+Nisin1000μg/mL，协同抑菌效果最佳。pH和乙醇协同抑制普通变形杆菌增殖，乙醇浓度越大，抑制效应越好，pH=6.0时，µmax最大；③研究了SSO在NaCl、温度、Aw和pH等作用下生长/非生长转化的生物膜等生理学和能量学响应机制。表明5℃条件下，Aw为0.97时，蜂房哈弗尼菌利用单糖和部分二糖，普通变形杆菌主要利用部分二糖和多糖。Aw为0.98时，两菌利用糖类、羧酸类、氨基酸类、胺/酰胺和脂肪酸/酯类、其他类的µmax均值显著大于Aw为0.97时。25℃和Aw（0.92~0.98）时，两菌均能利用糖类、氨基酸类和羧酸类等碳源。随Aw增高，碳源代谢能力增强，µmax和λ呈增大和减小趋势；随NaCl浓度增加，碳源利用逐渐减弱，增至3%时，几乎完全抑制，pH5.0~7.0时，两菌碳源代谢差异不大；④分析了原料（鲜品和冻品）品质、加工要素（腌制、干燥）、抑菌因子（盐分、Aw、乙醇等）和生物抑菌（短乳杆菌、酿酒酵母等）等协同作用下的产品品质特征。以鲜大黄鱼为原料，采用湿腌（6g/L NaCl）和冷风干燥等手段，适口性较好（水分含量60%），结合发酵剂（短乳杆菌和酿酒酵母等）协同抑菌，酿酒酵母使产品风味柔和，短乳杆菌和红酒糟高效协同抑菌。为解决加工轻微化与安全风险增加的矛盾，靶向控菌、货架期延长及新品开发提供支撑。