In-vitro digestion of refined kenaf seed oil microencapsulated in β-cyclodextrin/gum arabic/sodium caseinate by spray drying

Refined kenaf seed oil was microencapsulated by spray drying using the wall materials of β-cyclodextrin (β-CD), gum arabic (GA), and sodium caseinate (SC) to produce three different models (SC:β-CD, GA:β-CD, GA:SC:β-CD) of microencapsulated refined kenaf seed oil (MRKSO). An in-vitro digestion was used to simulate the human gastrointestinal digestion to examine the oil release behavior of MRKSO, changes in antioxidant activity and bioactive compounds of undigested oil, digested oil, and digested MRKSO samples. The results showed that three models of the MRKSO offered good protection by a lower percentage of oil released (1.43-6.44%) in the simulated gastric fluid and a high percentage of oil released (81.10-91.19%) after simulated gastric and intestinal phases digestion. The degree of lipolysis was in the order of SC:β-CD > GA:SC:β-CD > GA:β-CD > un-encapsulated oil. Among three models of MRKSO, GA:SC:β-CD offered better bioaccessibility by showing an increase in DPPH (20.0% increase) and ABTS (5.0% increase) values, phenolic content (130.4% increase), tocopherol and tocotrienol contents (147.7% increase), as well as slower degradation of phytosterol contents (59.4% decrease) after in-vitro digestion, compared to the undigested kenaf seed oil.