Shelf-life in cucurbitacin-containing phytonematicides: Non-conformity to Arrhenius model

Shelf-life information provides end-users with the assurance that the product is still in compliance with label claims. Behavioral reaction orders of the Arrhenius model had been consistently used under fixed conditions to provide shelf-life in food products. Due to non-conformity of the cucurbitacin-containing phytonematicides to the Arrhenius behavioral reaction orders, an alternative quadratic model consistent with the behavioral reaction orders of cucurbitacins was developed under chilled (5°C at 95–98% RH) and fixed tropical (38°C at 90% RH) conditions, while room temperature constituted unfixed conditions. Sampling for cucurbitacins was done at time-frames compliant with geometric series, with cucurbitacin analysis regularly performed using high-performance liquid chromatography techniques. Under chilled conditions, neither the Arrhenius nor the quadratic model could predict the shelf-life for Nemarioc-AL phytonematicide, whereas Nemafric-BL phytonematicide had shelf-life of 35 weeks. In contrast, under tropical conditions, the positive quadratic models showed that Nemarioc-AL and Nemafric-BL phytonematicides had shelf-life of 35 and 825 weeks, respectively. In conclusion, the two phytonematicides could be stored under fixed tropical conditions to enhance the shelf-life of their active ingredients.

货架期（shelf-life）信息可为终端用户提供产品仍符合标签声明的有效保障。长期以来，阿伦尼乌斯模型（Arrhenius model）的行为反应级数被广泛应用于固定条件下食品货架期的确定。由于含葫芦素（cucurbitacin）的植物源杀线虫剂（phytonematicides）不符合阿伦尼乌斯模型的行为反应级数，本研究在冷藏（5℃、相对湿度95%~98% RH）与固定热带环境（38℃、相对湿度90% RH）条件下，开发了一种与葫芦素行为反应级数相符的替代二次模型；其中室温环境属于非固定条件。葫芦素的采样严格遵循几何级数设定的时间区间开展，其分析工作常规采用高效液相色谱（high-performance liquid chromatography）技术完成。在冷藏条件下，阿伦尼乌斯模型与二次模型均无法预测Nemarioc-AL型植物源杀线虫剂的货架期，而Nemafric-BL型杀线虫剂的货架期为35周。与之相反，在热带固定条件下，正向二次模型结果显示Nemarioc-AL与Nemafric-BL型植物源杀线虫剂的货架期分别为35周与825周。综上，两种植物源杀线虫剂可在固定热带环境条件下储存，以延长其有效成分的货架期。