Volatile Retention and Morphological Properties of Microencapsulated Tributyrin Varied by Wall Material and Drying Method

Butyric acid is an important short-chain fatty acid for intestinal health and has been shown to improve certain intestinal disease states. A triglyceride containing 3 butyric acid esters, tributyrin (TB) can serve as a source of butyric acid; however, the need to target intestinal delivery and mitigate unpleasant sensory qualities has limited its use in food. Microencapsulation, the entrapment of one or more cores within a matrix, may provide a solution to the aforementioned challenge. This research primarily focused on the influence of (1) wall material: whey and soy protein isolate (WPI and SPI, respectively) and gamma-cyclodextrin (GCD), (2) wall additives: inulin of varying chain length, and (3) processing method: spray or oven drying (SD or OD, respectively) on the morphological properties and volatile retention of TB within microcapsules. SPI-based microcapsules retained significantly less (P < 0.001) TB compared to WPI-based microcapsules as measured by gas chromatography. The inclusion of inulin in the SD WPI-based microcapsules increased (P < 0.001) TB retention over WPI-based microcapsules without inulin. Inulin inclusion into WPI-based microcapsules resulted in a smoother, minimally-dented, circular morphology as compared to noninulin containing WPI-based microcapsules as shown by scanning electron microscopy. GCD and TB OD microcapsules retained more (P < 0.001) TB (94.5% ± 1.10%) than all other WPI, WPI-inulin, and GCD TB SD microcapsules. When spray dried, the GCD-based microcapsules exhibited (P < 0.001) TB retention than all other microcapsules, indicating the GCD may be unsuitable for spray drying. These findings demonstrate that microencapsulated TB in GCD can lead to minimal TB losses during processing that could be utilized in functional food applications for intestinal health.