*Corresponding author email: gnoratto@tamu.edu Symbiosis Group Symbiosis www.symbiosisonline.org www.symbiosisonlinepublishing.com Aged American Cheddar Cheese as Source of Protein Derived Compounds that Modulate Obese Mice Fecal Bacteria and Colon Inflammation In Vitro Luis Condezo-Hoyos 1,3 , Giuliana D Noratto 1,2 * 1 School of Food Science, Washington State University 2 Current address: Department of Nutrition and Food Science, Texas A&M University 3 Current address: Faculty of Medicine, Universidad Autónoma de Madrid, Spain Journal of Nutritional Health & Food Science Open Access Research Article Received: September 13, 2016; Accepted: October 26, 2016; Published: November 08, 2016 *Corresponding author: Dr. Giuliana Noratto, Ph.D, Department of Nutrition and Food Science, Texas A&M University. 1500 Research PKWY, Centeq A, Room 220D, College Station, TX 77845. Fax: 979 862 4056; Tel: 979-571-0272; E-mail: gnoratto@tamu.edu from milk and coagulant, as well as proteolytic activity of Starter Lactic Acid Bacteria (SLAB) and Non-Starter Lactic Acid Bacteria (NSLAB). In addition, cheese produced with Lactobacillus helveticus as adjunct culture has been reported to produce novel flavors, to improve acceptability of reduced-fat cheddar cheese, and to increase concentrations of low molecular weight peptides due to its high proteolytic activity and ability to autolyze [1]. The use of the L. helveticus strain as an adjunct to traditional starter cultures has been studied in cheese ripening. Results have shown that it produces a strongly flavored cheese within a relatively short period (2 mo). The main feature of the adjunct culture L helveticus is its ability to autolyze during cheese ripening which contributes to improved flavor [1]. This is evidenced by the release of intracellular enzymes such as d-lactate dehydrogenase and prolinase [2]. In addition, peptides produced by L. helveticus have been demonstrated to possess biological activity as angiotensin converting enzyme inhibitors in fermented dairy products. L. helveticus has genes responsible for key metabolic functions such as proteolysis, lipolysis, and cell lysis. Thus, some health benefits of milk fermented with L. helveticus include the blood pressure lowering effect in a human clinical trial associated with the peptides-induced inhibition of Angiotensin Converting Enzyme (ACE), a molecule that promotes vasoconstriction. A study examined the effects of 8 mo ripened Gouda-type cheese produced using L. helveticus in addition to the starter culture bacteria. Results showed the suppression of abdominal adipose tissue accumulation in rats fed freeze dried cheese on a 20% fat diet compared with rats given butter oil and casein in isocaloric diet [3]. The cheese diet also led to changes in metabolic syndrome markers and inflammation such as reduction of serum cholesterol, triglycerides, very low density lipoprotein, low-density lipoprotein, and reduction on production of Abstract Intestinal bacteria are key component in obesity and obesity- induced inflammation that leads to chronic diseases. Lactobacillus helveticus, a highly autolytic and proteolytic strain, has been associated with dairy products with health benefits. We investigated protein changes in American cheddar cheese manufactured with Lactobacillus helveticus (Cougar Gold brand, CG) during ripening, and their potential as modulators of fecal bacteria and colon Reactive Oxygen Species (ROS) in vitro. Results confirmed that casein-derived products and proteins/peptides released after In Vitro Digestion (IVD) shifted DNA abundances of Enterobacteriaceae, Enterococcus, and Bifidobacterium spp. in obese mice feces to resemble lean mice. CG fecal fermentation metabolites protected human colon fibroblast CCD-18Co cells against production of ROS. Overall, proteins in aged cheese might help to improve obese fecal bacteria balance and protect against obesity-induced colon inflammation. Further in vivo studies are needed to validate these findings and to confirm the intestinal beneficial value of ripened cheese. Keywords: Cheese Proteins; Cheese Ripening, Obese Fecal Bacteria, Colon Inflammation Abbreviations CG: Cougar Gold brand; ROS: Reactive oxygen species; IVD: In vitro digestion; SLAB: Starter lactic acid bacteria; NSLAB: Non- starter lactic acid bacteria; MRPs: Maillard reaction products; AGEs: Advanced glycation end-products; PCR: Polymerase chain reaction; SCFAs: Short-chain fatty acids; RFU: Relative fluorescence units; PCA: Principal component analysis; Introduction Proteolysis of cheese caseins can be attributed to enzymes