# Proteomics Analysis in Dairy Products: Cheese, a Review
## 8 Bioactive Peptides  
In the past few years there has been a rising need in the industry for reagents that can be received through food and can contribute to improving and maintaining the status of wellness and prevent the appearance of chronic diseases. The need for wellbeing regimes can be obtained by consumption of various meat and vegetable products [97]. Peptides are small molecules with weight less than 10 kDa and can be found naturally in foods or occur by chemical or enzymatic hydrolysis of the parent proteins [98]. Usually peptides are latent, when encrypted into proteins, and become active, when released after proteolysis or digestion in gastrointestinal (GI) tract [99]. They affect many physiological functions in the human body, such as gastrointestinal, cardiovascular, immune, endocrine, and nervous pathways. One of the most important, and accessible to the majority of people, sources of beneficial peptides is milk and dairy products in general [100; 101]. As previously discussed, these peptides are well protected in the protein matrix of milk,requiring proteolytic enzymes, originating from various sources, such as natural rennet or starter bacteria, for their release. A growing body of evidence indicates that milk and dairy products have unique metabolic, signaling and antimicrobial effects, apart from their high nutritional content [102; 103; 104; 105]. Such peptides are involved in many physiological activities, including regulation of inflammatory and immune response, signaling and metabolic process, antihypertensive, antioxidant and antimicrobial properties [105]. According to previous studies, pasta filata cheeses (Caciocavallo and Mozzarella) have antibacterial peptides [106]. [PERSON] et al. [106] conducted in vitro simulated gastrointestinal digestion on six buffalo dairy products (Grana, ice cream, yoghurt, Mozzarella, Ricotta and Scandorza) and the isolated peptide digests were characterized by high resolution mass spectrometry, followed by a database-driven specific bioactivity assessment for each identified sequence. The study revealed a great amount of potential bioactive peptides, with characteristics promoting wellness, including antihypertensive, immunomodulatory, antimicrobial, antidiabetic, anticancer and antioxidant. The different manufacturing process of each product explained the diversity of the released peptides. Antimicrobial peptides (AMPs) with resistance in proteolysis have a direct impact on the gut microbiome assisting to control dysbiosis, by suppressing opportunistic pathogens, such as _Helicobacter pylori_[107], _Escherichia coli_ and _Staphylococcus aureus_[108], so that the GI tract can remain healthy. The milk and dairy products from different animal breeds and species have unique compositions of bioactive peptides offering a broad range of sequences to screen for peptides with functional traits of medical and scientific interest [109]. [PERSON] et al. [102] focused on the potential antimicrobial properties of Feta cheese, to probe for AMPs following an assessment of their stability in an intestine-like environment and they characterized the antimicrobial \"load\" of the proteomes of interest. Protein sequences from Feta cheese were screened using the publicly available tool AMPA [110; 111] to find sequence stretches with predicted high antimicrobial potential (i.e., low AMPA propensity). The same protein sequences were digested in silico to identify which peptides, that can actually occur in the GI tract, matched the predicted AMPA stretches. The authors stated that Feta cheese proteome had 63-64 AMPs the same with the milk from the sheep and goat breeds, used to manufacture Feta. Albeit the small proteome size of Feta cheese, the proteome presents to have unique antimicrobial properties and resistance in proteolysis AMPs in quite a large amount. Recent work has suggested that lactic acid microbes have a central role in the release of encrypted bioactive peptides during ripening [112].