Abstract #306

# 306
The dairy matrix—Bioaccessibility of nutrients and physiological effects.
S. L. Turgeon*1, 1STELA Dairy Research Centre and Institute of Nutrition and Functional Foods (INAF), Department of Food Science, Université Laval, Québec City, QC, Canada.

Studies have linked food structure and texture to kinetics of nutrient delivery. Changes in some nutrient release rates, such as for protein and lipids, could induce different physiological effects (e.g., satiety effect, reduction of postprandial lipemia). Examples will be presented to showcase the contribution of dairy food structure, as found in yogurt and cheese, on nutrient release rates. The impact of the casein:whey protein ratio or fiber addition on digestion kinetics of protein, and subsequently, satiety, was examined in one study. A static in vitro digestion model was used on experimental yogurts differing in the casein-to-whey protein ratio (C:W) or dietary fiber content. Healthy men (20) consumed the 5 isocaloric/isoproteinemic yogurt snacks previously studied. Ad libitum food intake was monitored 2.5 h post-snack consumption. A human clinical trial revealed that yogurt formulation with increased whey protein content significantly reduced subsequent energy intake compared with the control, and increased satiety. This result was linked to a slower in vitro disintegration rate. Soluble protein release for yogurt increased in whey protein whereas no difference was observed for yogurts with fiber. A second study allowed for the discrimination of the effects of cheese attributes on lipid release and absorption. Nine commercial cheeses were digested in vitro and 2 were selected for an in vivo study. Healthy women/men (43) ingested 33 g of fat from cheddar, cream cheese or butter, incorporated in a standardized meal. Plasma concentrations of triglycerides (TG) were measured before the meal and at 2, 4, 6 and 8 h. At the end of the in vitro gastric digestion, cheddar and cream cheese showed different disintegration, attributed to the texture and manufacturing processes. The in vivo study revealed that cream cheese, but not cheddar, induced a more important increase in TG concentrations than the butter (Δ vs baseline: +44% vs +24%, P = 0.002) at 2 h. These studies demonstrate that the dairy food matrix per se modulates nutritional properties. Studies published on this topic will be included to put into perspective the role of the dairy food matrix on nutrient release, the physiological effects, and how this can be compared with other foods.

Key Words: nutrient delivery, dairy food, food structure

Speaker Bio
Dr. Sylvie Turgeon obtained her Ph.D. in Food Science and Technology at Laval University in 1991. She has been the director of the STELA Dairy Research Centre at Laval University for 9 years until 2012. She is currently professor at the Department of Food Science and director of the Institute on nutrition and functional foods. This Institute brings together researchers to study the link between food, their components, nutritional and health impacts. Dr Turgeon’s main scientific interests aims to understand the molecular interactions in food to apprehend the functionality of proteins and polysaccharides. This knowledge should allow controlling the food structure which is the key to food product stability, organoleptic properties but also its nutritional properties. 
She has developed an original research area to study the link between food composition/structure/process/nutritional properties. Her recent research looks at the intrinsic nutritional qualities of dairy products as related to their structural organization. 
Other topics include: functionality of dairy products, impact of processing steps, link between food chemistry and culinary sciences in support of the development of gastronomic sciences.