Development of Oat bran based fiber-rich beverage and its corresponding placebo for a clinical trial

Abstract: Oats have been gaining huge popularity in the past three decades, due to its well-known positive effects in serum cholesterol levels, glucose homeostasis and insulinemia. A growing body of evidence shows a link between obesity, metabolic dysfunctions and gut microbiota composition. The main objective of the project is to develop an oat bran and milk based fiber-rich beverage and an oat based yogurt, that would promote increasing the average consumption of fiber from the current 15 g/day estimated for the European population, to the actual recommended daily level of 25 - 38 g/day for women and men, respectively, when consumed as a part of daily diet. A placebo for the oat beverage is also developed, which would be used along with the test product in a clinical trial for glyceamic control and weight management. Several trials for development of oat beverage and yogurt was carried out using three different oat bran flours: OBA, OBB and OBC with varying β-glucan content (10 g, 15 g and 28 g per 100 g oat flour respectively) and three different processing methods and varying concentrations of milk (5 - 50 %). The trials for the placebo was carried out using four different rice-based ingredients (RF, RS, RM and MD). The flavor of the oat drink was optimized after trying out 60 flavors and 33 combinations. The developed products were characterized using physical measurements such as viscosity, pH and moisture analysis, enzymatic analysis for β-glucan content, maltose, sucrose and glucose contents and sensory analysis. The nutritional content and percentage of dry oats was also estimated. Sensory analyses revealed that, among the three variants, OBC oat drink had significantly higher scores for taste, texture and appearance. OBA oat drink performed better in yogurt application, in terms of taste and texture. Two flavor combinations were identified for the oat drink (Tea+cinnamon+ginger and coffee+caramel+vanilla), but no significant difference was observed between these two flavors, in terms of sensory acceptance. A placebo with similar organoleptic and nutritional properties as the oat drink was developed using rice flour. The developed products – the oat drink and oat yogurt - have a β-glucan content of 3 g and 1 g per 250 ml serving, respectively, which fulfills the amount required for the health claim of providing 3 g beta glucans/ day, according to EFSA guidelines for cholesterol lowering effect of oat β-glucans.