Encapsulation of papaya seed oil in casein-alginate-based shell materials

This study aimed to develop papaya seed oil macrocapsules using ionotropic gelation encapsulation with casein and sodium alginate as shell materials. Mechanical stability and physical properties, assessed via response surface methodology, were used to determine optimal conditions. Bioaccessibility and oil release post in-vitro gastrointestinal digestion were also quantified. Independent variables (papaya seed oil concentration, calcium chloride percentage, and pH) were examined, revealing correlation coefficients (R2) of 0.938, 0.957, 0.954, and 0.845 for elastic limit, Young modulus, oil loss capacity, and capsule diameter, respectively. Optimal encapsulation conditions were identified as 60% papaya seed oil, 0.5% calcium chloride (w/v), and pH 2, resulting in macrocapsules with an elastic limit of 176.84 Pa, Young modulus of 4.44 Pa, oil loss capacity of 19.81%, and a capsule diameter of 2.727 mm. In-vitro studies indicated a target oil release of 52.23%, primarily in the intestinal phase, with a bioaccessibility of 75.36%. This study underscores the impact of encapsulation process conditions on macrocapsule properties and highlights the potential application of casein alginate macrocapsules as oral delivery vehicles for lipophilic compounds in the food and nutraceuticals industry.