Fungi are commonly identified as the cause for dairy food spoilage. This can lead to substantial economic losses for the dairy industry as well as consumer dissatisfaction. In this context, biopreservation of fermented dairy products using lactic acid bacteria, propionibacteria and fungi capable of producing a large range of antifungal metabolites is of major interest. In a previous study, extensive screening was performed in vitro and in situ to select 3 dairy fermentates (derived from Acidipropionibacterium jensenii CIRM-BIA1774, Lactobacillus rhamnosus CIRM-BIA1952 and Mucor lanceolatus UBOCC-A-109193, respectively) with antifungal activity. The aim of the present study was to determine the main compounds responsible for this antifungal activity. Fifty-six known antifungal compounds as well as volatiles were targeted using different analytical methods (conventional LC and GC, GC-MS, LC-QToF). The most abundant antifungal compounds in P. jensenii-, L. rhamnosus- and M. lanceolatus-derived fermentates corresponded to propionic and acetic acids, lactic and acetic acids, and butyric acid, respectively. Many other antifungal compounds (organic acids, free fatty acids, volatile compounds) were identified but at lower levels. In addition, an untargeted approach using nano LC-MS/MS identified a 9-amino acid peptide derived from αs2-casein in the L. rhamnosus-derived fermentate. This peptide inhibited M. racemosus and R. mucilaginosa in vitro. This study provides new insights on the molecules involved in antifungal activities of food-grade microorganism fermentates which could be used as antifungal ingredients in the dairy industry.

中文翻译：

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发酵乳制品成分的抗真菌活性：鉴定抗真菌化合物。

真菌通常被认为是导致乳制品腐败的原因。这可能导致乳制品行业的巨大经济损失以及消费者的不满。在此背景下，使用能够产生大量抗真菌代谢物的乳酸菌，丙酸杆菌和真菌对发酵乳制品进行生物保存是非常重要的。在先前的研究中，在体外和原位进行了广泛的筛选，以选择3种具有抗真菌活性的乳制品发酵液（分别来自詹氏酸性酸杆菌，CIRM-BIA1774，鼠李糖乳杆菌CIRM-BIA1952和Mucor lanceolatus UBOCC-A-109193）。本研究的目的是确定引起这种抗真菌活性的主要化合物。使用不同的分析方法（常规LC和GC，GC-MS，LC-QToF）确定了五十六种已知的抗真菌化合物以及挥发物的目标。在詹氏疟原虫，鼠李糖乳杆菌和轮叶分枝杆菌衍生的发酵物中最丰富的抗真菌化合物分别对应于丙酸和乙酸，乳酸和乙酸以及丁酸。鉴定出许多其他抗真菌化合物（有机酸，游离脂肪酸，挥发性化合物），但含量较低。另外，使用纳米LC-MS / MS的非靶向方法鉴定了源自鼠李糖乳杆菌的发酵物中αs2-酪蛋白的9个氨基酸肽。该肽在体外抑制消旋支原体和粘菌R. mucilaginosa。