Encapsulation of piperine in metal organic frameworks and evaluation of its stability, characteristics, in-vitro digestion and product fortification

Abstract

Piperine is a phytochemical known for its health beneficial properties. However, it suffers from poor solubility and stability in the aqueous system. This could be the major hurdle for the application of piperine in functional foods. These drawbacks were addressed with the encapsulation using metal organic frameworks. Therefore, his study investigates the synthesis and application of β-cyclodextrin based metal-organic frameworks (β-CD-MOFs) as a carrier for piperine encapsulation in order to enhance its solubility and stability. The β-CD-MOF and piperine were combined in different ratios (1:1, 1:2, 1:3, 1:4, 2:1, 3:1 and 4:1) for the encapsulation and optimal ratio was selected based on loading efficiency. The β-CD-MOF-to-piperine ratio of 1:2 was identified as optimal, achieved a highest loading rate of 15.36 %. SEM analysis observed a slight increase in the size of β-CD-MOF from 429.63 ± 13 nm to 463.80 ± 48 nm after encapsulation of piperine. FTIR analysis confirmed the encapsulation and retention of basic structure of MOF. XRD analysis demonstrated the retention of MOF's crystalline structure following the encapsulation of piperine. Storage study showed that the encapsulated piperine maintained absolute antioxidant activity over three months of storage at 30°C. The encapsulated piperine maintained maximum stability at various pH, processing temperature and ionic conditions. During in-vitro digestion, the antioxidant activity of encapsulated piperine was decreased from 92.92 ± 0.37 % at oral phase to 86.66 ± 0.57 % at gastric phase and 85.33 ± 0.76 % at intestinal phase. Encapsulated piperine was incorporated in flavored milk at the concentration of 10, 12.5, and 15 mg/ml and achieved an antioxidant activity of 87.11 ± 0.32 91.86 ± 0.68 and 94.45 ± 0.78 %, respectively. Sensory evaluation revealed that even lower piperine concentration (10 mg/ml) showed remarkable spiciness and pungency. Overall, this study offers valuable insights into the stabilization and delivery of piperine through β-CD-MOFs, paving the way for their application in functional foods and nutraceuticals.