de Nijs Monique, Mulder Patrick P J, Klijnstra Mirjam D, Driehuis Frank, Hoogenboom Ron L A P
a RIKILT Wageningen University & Research , Wageningen , the Netherlands.
b NIZO Food Research , Ede , the Netherlands.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2017 Dec;34(12):2212-2219. doi: 10.1080/19440049.2017.1364432. Epub 2017 Aug 25.
To investigate the fate of pyrrolizidine alkaloids (PAs) during milk processing, milk of cows treated via rumen fistula with a mixture of 84% (w/w) ragwort (Jacobaea vulgaris, syn. Senecio jacobaea) and 16% narrow-leaved ragwort (Senecio inaequidens) was processed using laboratory scale heating systems with industrial settings. Pasteurised and sterilised (UHT) milk were produced, as well as set-type yoghurt and cheese. Samples were analysed for 29 PAs using LC-MS/MS, of which 11 PAs were detected above LOQ in the samples (0.1 µg l). Alterations in the PA concentration and composition between the standardised milk and the corresponding end-product(s) were evaluated. The heat treatments applied for pasteurisation and UHT sterilisation to prepare semi-skimmed consumption milk did not affect the PA levels in the end-products. In yoghurt, after fermentation of standardised milk (6 h, pH 4.4), 73% of total PAs were recovered. The PA concentration, specifically dehydrojacoline, was decreased, although not quantifiable, during cheese production. A further decrease of 38% during 6 weeks of ripening was observed. The results show that the PA concentration of natural contaminated cow's milk is not affected by heat treatment applied for pasteurised and sterilised milk, but that microbial fermentation of the milk leads to a lowered PA concentration in yoghurt and cheese. This is probably due to microbiological degradation, since PAs are fairly stable under acidic conditions.
为研究牛奶加工过程中吡咯里西啶生物碱（PAs）的去向，通过瘤胃瘘管给奶牛投喂由84%（w/w）欧洲千里光（Jacobaea vulgaris，syn. Senecio jacobaea）和16%窄叶千里光（Senecio inaequidens）组成的混合物后，采集牛奶，使用具有工业生产条件的实验室规模加热系统对牛奶进行加工。制备了巴氏杀菌奶和超高温灭菌（UHT）奶，以及凝固型酸奶和奶酪。使用液相色谱 - 串联质谱法（LC-MS/MS）对29种PAs进行分析，其中在样品中检测到11种PAs的含量高于定量限（0.1 μg/l）。评估了标准化牛奶与其相应最终产品之间PAs浓度和组成的变化。用于制备半脱脂消费奶的巴氏杀菌和UHT灭菌热处理对最终产品中的PAs水平没有影响。在酸奶中，标准化牛奶发酵（6小时，pH 4.4）后，回收了73%的总PAs。在奶酪生产过程中，PAs浓度，特别是脱氢夹可啉的浓度有所下降，尽管无法定量。在成熟6周期间，进一步下降了38%。结果表明，天然受污染牛奶中的PAs浓度不受巴氏杀菌奶和灭菌奶热处理的影响，但牛奶的微生物发酵会导致酸奶和奶酪中的PAs浓度降低。这可能是由于微生物降解，因为PAs在酸性条件下相当稳定。
