Enzymatically modified quinoa starch based pickering emulsion as carrier for curcumin: Rheological properties, protection effect and in vitro digestion study

Curcumin, as a lipid-soluble and environment-sensitive (light, heat and oxidants) polyphenol, need to be embedded to develop health care products with stable storage-stability and of higher bioaccessibility. Enzymatically modified quinoa starch (EMQS) based emulsion gel was fabricated and used as the carrier for curcumin. The emulsifying property and mechanism of EMQS, and the micromorphology, stability, rheological properties and in vitro digestion properties of the emulsion gel were studied. The decreased particle size and increased contact angle of QS after enzymatic hydrolysis contributed to the improved emulsifying properties of EMQS. The curcumin-encapsulated EMQS Pickering emulsion gel showed better emulsifying stability, much clearer solid-like behavior, higher gel strength and viscosity than that of Tween 80 emulsion. The retention rates of curcumin in the EMQS Pickering emulsion gel were higher than 85% after subjected to the different treatments. And under 7 h UV and 8-day storage conditions, the protective effect of EMQS-based Pickering emulsion gel on curcumin was even higher than that of tween 80 emulsion system. The lipid digestion extent in EMQS Pickering emulsion gel was higher than that in bulk oil system and lower than that in tween 80 system. Compared with that of bulk oil system (5.37%), the bioaccessibility of curcumin in EMQS Pickering emulsion gel (38.57%) was greatly improved, proving that EMQS Pickering emulsion gel could be used as delivery vehicle for curcumin.