Impact of the Food Matrix on the Antioxidant and Hypoglycemic Effects of Betalains from Red Prickly Pear Juice After In Vitro Digestion

This study evaluated the impact of the food matrix on the bioaccessibility and hypoglycemic potential and antioxidant potential of betalains from red prickly pear juice (Opuntia spp.) after in vitro gastrointestinal digestion. Six aqueous model systems (AMSs) were formulated using a betalain extract combined with glucose, citric acid, mucilage, pectin, or all components, alongside three complex matrices, the fresh juice (FJ), a formulated beverage (BF), and a pasteurized formulated beverage (BP). In vitro digestion simulated the gastric and intestinal phases. The results showed that complex matrices (FJ, BF, and BP) enhanced betalain bioaccessibility, with FJ exhibiting the highest bioaccessibility (59%). Mucilage and pectin provided the strongest protection, reducing betalain degradation by 30% and 25%, respectively, while citric acid had a destabilizing effect. Pasteurization (BP) reduced betalain stability compared to FJ and BF. Antioxidant activity decreased post-digestion but remained higher in BF. Notably, FJ showed the highest inhibition of α-amylase (72%) and α-glucosidase (68%), surpassing acarbose (50–60% inhibition). These findings highlight the critical role of the food matrix, particularly mucilage and pectin, in stabilizing betalains through non-covalent interactions and enhancing their hypoglycemic potential. Red prickly pear juice emerges as a promising functional food for managing postprandial glucose levels, offering valuable insights for developing betalain-rich foods to address type 2 diabetes.