| Functional foods have not only been a phenomenon of the past few decades; 2500 years ago Hippocrates suggested, "let food be thy medicine and medicine be thy food". The Health Canada working definition for functional foods states that a functional food is similar in appearance to, or may be a conventional food, is consumed as part of a usual diet and is demonstrated to have physiological benefits and/or reduce the risk of chronic disease beyond basic nutritional functions. Agriculture and Agri-food Canada indicate a tremendous potential for developing function foods from dairy.; There is increasing evidence indicating that lactic acid bacteria (LAB) and milk proteins (MP) may modulate many disease states. The majority of studies use LAB of human origin; while dairy LAB represent a large population of bacteria with unexploited potential. Furthermore, studies are beginning to demonstrate that biotransformation of bacterial growth medium results in the liberation of many bioactive proteins/peptides that may also be used to modulate disease. There is a strong lack of understanding regarding the mechanism through which these compounds alter disease state; in addition, there is a strong need to have well characterized functions of individual ingredients before introduction as a functional food ingredient.; Thus, the objective of this thesis research was to identify new functional ingredients derived from dairy LAB isolates and proteins that can be used as dietary adjuvants in the modulation of gastrointestinal disorders. The following biomarkers were investigated: antimutation, adhesion properties and mechanisms of adhesion of LAB, apoptotic, necrotic and cytotoxic action of LAB and MP against cancer cells. We also investigated the ability of LAB isolates and MP to modulate the secretion of TNFalpha, IL-6 and nitric oxide from macrophage cells. We found that each of the LAB tested was strongly adhesive and the adhesion mechanisms varied in a strain dependent manner. We found that LAB and MP were able to prevent mutation, induce cellular death and modulate the immune response, in a strain or MP specific manner. These findings and their possible applications in gastrointestinal disease modulation will be discussed. |
