Gastrointestinal digestion of Pickering emulsions stabilised by hydrophobically modified cellulose nanocrystals: Release of short-chain fatty acids.

This study aimed to deliver short-chain fatty acids (SCFAs, including propionic and butyric acids) using Pickering emulsions stabilised by hydrophobically modified cellulose nanocrystals (MCNCs). The emulsions (20 wt% oil, 1 wt% MCNCs) were subjected to two in vitro digestion pathways. In the first pathway, the emulsions were used for direct intestinal digestion by bypassing the gastric phase while in the second pathway, the emulsions were subjected to sequential gastrointestinal digestion. Flocculation of emulsion droplets occurred because of charge screening effects by the gastric electrolytes. Such gastric flocculation reduced the droplet surface area, overall lipolysis kinetics and consequently decreased the extent of SCFA release, latter was 40-45% in the gastric-bypassed emulsions and 30-35% in the sequentially-digested emulsions. High proportion of SCFAs remaining after the intestinal digestion (~65%) shows promise in the use of Pickering emulsions for the colon-targeted delivery of SCFAs.

Application of ultrasound to microencapsulation of coconut milk fat by spray drying method.

Mixtures of coconut milk and gelatin solution were treated by ultrasound, mixed with maltodextrin and subsequently spray-dried to yield powder. The effects of ultrasonic power and sonication time on the microencapsulation efficiency (ME) and microencapsulation yield (MY) of coconut fat were investigated. The results indicated that increase in ultrasonic power from 0 to 5.68 W/g and in sonication time from 0 to 2.5 min augmented ME and MY of coconut fat. However, treatment with sonication power higher than 5.68 W/g led to a drop in fat ME and MY, mainly due to aggregation of fat particles and that blocked the adsorption of gelatin molecules on the particle surface.

Impact of high temperature on ethanol fermentation by Kluyveromyces marxianus immobilized on banana leaf sheath pieces.

Ethanol fermentation was carried out with Kluyveromyces marxianus cells at various temperatures (30, 35, 40, and 45 °C). Fermentation performance of the immobilized yeast on banana leaf sheath pieces and the free yeast were evaluated and compared. Generally, ethanol production of the immobilized and free yeast was stable in a temperature range of 30-40 °C. Temperature of 45 °C restricted yeast growth and lengthened the fermentation. The immobilized yeast demonstrated faster sugar assimilation and higher ethanol level in the fermentation broth in comparison with the free yeast at all fermentation temperatures. Change in fatty acid level in cellular membrane was determined to clarify the response of the free and immobilized yeast to thermal stress. The free cells of K. marxianus responded to temperature increase by increasing saturated fatty acid (C16:0 and C18:0) level and by decreasing unsaturated fatty acid (C18:1 and C18:2) level in cellular membrane. For fermentation at 40 °C with immobilized cells of K. marxianus, however, the changes were not observed in both saturated fatty acid (C16:0) and unsaturated fatty acid (C18:1 and C18:2) level.