Multidimensional evaluation of the effects of pre-gelatinized purple sweet potato flour on the characteristics and glycaemic response of yogurt drink

Purple sweet potato (Ipomoea batatas L.) is rich in bioactive compounds with antioxidant activity. Pre-gelatinized purple sweet potatoes can be used in low-sugar yogurt drink products. This study aims to evaluate the effect of adding pre-gelatinized purple sweet potato flour on the characteristics and glycaemic response of yogurt drinks. The research consisted of two stages. The first stage employed the Mixture Design method to obtain the formulation with the highest antioxidant activity. The second stage involved comprehensive characterization, including physio-chemical, microbiological, sensory by the Temporal Dominance of Sensations method, and glycaemic index analyses. The optimized formulation (6 % pre-gelatinized purple sweet potato flour, 0.04 % stevia, and 2.96 % erythritol) showed the highest antioxidant activity (84.7 %). The addition of pre-gelatinized flour significantly improved the antioxidant component, lactic acid bacteria viability, and viscosity compared to formulations containing non-pre-gelatinized flour and without purple sweet potato. Furthermore, the pre-gelatinized formulation enhanced the presence of organic compounds that contribute to the product's sweet aroma. In contrast, the pre-gelatinized sample showed a lower carbohydrate, protein, and fat content. Sensory analysis revealed sweetness, sourness, and purple sweet potato flavour as dominant attributes. The pre-gelatinized sample also showed a low glycaemic index and stable post-prandial glucose response.