Yvonne Roman Maldonado

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.

This study evaluated the impact of the food matrix on the bioaccessibility and hypoglycemic potential of betalains from red prickly pear juice (Opuntia spp.) after in vitro gastrointestinal digestion. Six aqueous model systems (AMS) were formulated using betalains extract combined with glucose, citric acid, mucilage, pectin, or all components, alongside two complex matrices, the fresh juice (FJ) and a formulated beverage (BF), the latter also pasteurized (BP). In vitro digestion simulated oral, gastric, and intestinal phases. Results showed that complex matrices (FJ, BF, BP) enhanced betalains bioaccessibility, with FJ exhibiting the highest bioaccessibility (59%). Mucilage and pectin provided the strongest protection, reducing betalains degradation by 30% and 25%, respectively, while citric acid had a destabilizing effect. Pasteurization (BP) reduced betalains 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 betalains-rich foods to address type 2 diabetes.

The red prickly pear fruit (Opuntia ficus-indica L. Mill), endemic from Mexico’s semi-desert regions and present in North Africa and Southern Europe, particularly Italy and Spain, is a valuable source of nutrients, bioactive compounds, and polysaccharides. This study used non-destructive techniques like microscopy and Raman and infrared (IR) spectroscopy to characterize polysaccharides extracted from two red prickly pear varieties. The polysaccharides constitute approximately 80% of the peel and 39–18% of the pulp; microscopy provided insights into its microstructural details, while Raman and IR spectroscopy enabled the identification of its specific functional groups. The results revealed distinct microstructural attributes: mucilage displays a microstructure influenced by the ratio of acidic to neutral sugar monomers; pectin exhibits a low degree of methoxylation alongside a characteristic egg-box structure facilitated by calcium ions; hemicellulose presents a delicate, porous layer; and cellulose reveals a layered microstructure supported by thin or robust fibers and calcium crystals. The functional groups identified via Raman and IR spectroscopy provided specific information that could be used to infer chemical interactions influenced by functional groups like hydroxyl, carboxyl, and methyl, suggesting potential binding, stabilization, and water retention properties that enhance their utility as functional ingredients in food products. These findings, obtained using non-destructive methods, enhance the understanding of the compositional and microstructural characteristics of polysaccharides in the red prickly pear, which, in turn, can be used to predict their promising technological applications as functional ingredients.