Microencapsulation is commonly used in the food industry to provide functional and sensory benefits to a variety of compounds. Tributyrin (TB), a source of butyric acid, is characterized by a highly bitter taste and negative odor attributes. Its use in the maintenance of intestinal health and treatment of intestinal disorders shows promise. However, due to the negative sensory qualities and necessity to target the intestinal epithelium, TB has yet to be widely utilized in a food system for treatment. The overall objectives of this study were to: 1) determine the impact of protein type, inulin chain length, and gamma-cyclodextrin (GCD) on the stability and retention of microencapsulated TB, 2) measure which TB microcapsule formulation imparts the least overall sensory difference in an infant formula system, 3) determine the site of intestinal delivery and release of butyrate from microencapsulated TB, and 4) determine the sensory properties of food products containing microencapsulated TB. Microencapsulated TB in whey protein isolate (WPI)-based microcapsules resulted in higher (p<0.001) retention than soy protein isolate (SPI)-based microcapsules. The inclusion of inulin WPI-based wall materials improved (p<0.01) the retention of TB for all chain lengths over WPI-based microcapsules without inulin. The creation of altered surface morphology from inulin is due to the ability of inulin to interact with the WPI-based wall material. This interaction creates added wall flexibility during drying and may be responsible for increased TB retention. The use of GCD resulted in the highest TB retention (95%) when oven dried but the lowest when spray dried (62%). In infant formulas, GCD and TB oven dried (GCT OD) microcapsules were able to reduce the sensory perception of TB to a level indistinguishable from a control infant formula containing no TB. All other WPI, WPI-inulin, and GCD-based microcapsules were significantly different from the control (R-index above 57% or at p<0.05) but not from free TB (p>0.05) as indicated by the rating method. During in vitro digestion, all microcapsules containing TB showed limited butyrate release (<5%) during oral and gastric stages. In then simulated small intestine, TB microcapsules released approximately 75% of their total butyrate content with no significant differences (p>0.05) across formulations. During fermentation, GCD-based microcapsules produced significantly more butyrate (p<0.001) on a molar basis than all WPI-based microcapsules. The microcapsule GCT OD was able to effectively deliver and produce butyrate in the small and large intestines. Results from the descriptive analysis (DA) test conducted using GCT OD in apple sauce, infant formula, and crackers, revealed that GCT OD behaved differently in each system due to the matricies physical properties. Combined common attribute principal correlation analysis (PCA) biplots show samples containing free TB were highly characterized by bitter taste and aftertaste. Cracker samples were not significantly different (p>0.05) for all measured attributes intensities as compared to free TB-containing samples, and were significantly higher in bitter taste and aftertaste. Apple sauce and infant formula containing GCT OD were significantly (p<0.05) reduced in bitter taste and aftertaste as compared to free TB samples. This bitter taste and aftertaste intensity for GCT OD was still, however, significantly higher (p<0.05) than the control for apple sauce and infant formula. The inclusion of GCT OD in infant formula had the least overall impact on the attributes that characterize control infant formula samples. Overall, findings from this research can be used to guide the production and application of microencapsulated TB for use in these and additional food products for the potential improvement of intestinal health or disease states.
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Microencapsulation of tributyrin to improve sensory qualities and intestinal delivery