The impact of salt and fat intake on human health drives the consumer's attention towards dairy food with reduced salt and fat contents. How changes in salt and fat content modulate dairy LAB population and the associated proteolytic activities have been poorly studied. Here, non-starter LAB populations from 12 Parmigiano Reggiano (PR) cheeses (12-month ripened), clustered in low salt and fat content (LL-PR) and high salt and fat content (HH-PR) groups, were investigated and identified at specie-level with molecular assays. Lactobacillus rhamnosus was dominant in HH-PR samples, whereas Lactobacillus paracasei in LL-PR samples. (GTG)₅ rep-PCR analysis discriminated 11 and 12 biotypes for L. rhamnosus and L. paracasei isolates, respectively. Screening for proteolytic activity identified L. rhamnosus strains more proteolytic than L. paracasei, and, within L. rhamnosus species, HH-PR strains were generally more proteolytic than LL-PR strains. Two L. rhamnosus representatives, namely strain 0503 from LL-PR and strain 2006 from HH-PR, were functionally characterized in cow milk fermentation assay. HH-PR strain 2006 overcame LL-PR strain 0503 in acidification performance, leading to a fermented milk with higher angiotensin I-converting enzyme inhibitory and antioxidant activities. L. rhamnosus 2006 was more prone to release VPP, while L. rhamnosus 0503 released higher amount of IPP. This study provides evidences that salt/fat content affects NSLAB cultivable fraction and the associated proteolytic ability resulting in a complex occurrence of bioactive peptides featuring health-promoting properties.

盐和脂肪摄入量对人体健康的影响促使消费者开始关注盐和脂肪含量降低的乳制品。盐和脂肪含量的变化如何调节乳品乳酸菌种群以及相关的蛋白水解活性的研究很少。在这里，调查了来自12种帕玛森芝士（PR）奶酪（成熟12个月）的非起步LAB种群，这些种群聚集在低盐和脂肪含量（LL-PR）和高盐和脂肪含量（HH-PR）组中。在分子水平上通过分子分析鉴定。鼠李糖乳杆菌在HH-PR样品中占主导地位，而副干酪乳杆菌在LL-PR样品中占主导地位。（GTG）₅ rep-PCR分析区分了鼠李糖乳杆菌和副干酪乳杆菌的11种和12种生物型分离。筛选蛋白水解活性鉴定出鼠李糖乳杆菌比副干酪乳杆菌更具有蛋白水解作用，并且在鼠李糖乳杆菌种中，HH-PR菌株通常比LL-PR菌株更具蛋白水解作用。在牛奶发酵测定中对两个鼠李糖乳杆菌代表，即LL-PR的0503菌株和HH-PR的2006菌株进行了功能表征。HH-PR菌株2006在酸化性能方面胜过LL-PR菌株0503，从而导致发酵乳具有更高的血管紧张素I转化酶抑制和抗氧化活性。鼠李糖乳杆菌2006更倾向于释放VPP，而鼠李糖乳杆菌0503释放了更高数量的IPP。这项研究提供了证据，表明盐/脂肪含量会影响NSLAB可培养级分和相关的蛋白水解能力，从而导致复杂的具有生物活性肽的健康活性肽出现。