Spray-air contact and operating conditions in tall and short-form co-current spray dryers affect relevant physico-chemical properties of microencapsulated chia oil (Salvia hispanica L.)

Utilization of gallic acid-crosslinked soy proteins as wall material for chia oil microencapsulation

BACKGROUND

Chia oil represents the vegetable source with the highest content of omega-3 fatty acids. However, the incorporation of polyunsaturated fatty acids into food is limited due to their susceptibility toward oxidation. This investigation aimed to study the microencapsulation of chia oil (CO), using gallic acid (GA) crosslinked-soy protein isolate (SPI) as a wall material and its effect on its oxidative stability.

RESULTS

Microcapsules presented a moisture content, water activity, and encapsulation efficiency of around 2.95-4.51% (wet basis); 0.17 and 59.76-71.65%, respectively. Rancimat tests showed that with higher GA content, the induction period increased up to 27.9 h. The storage test demonstrated that the microencapsulated oil with crosslinked wall material has lower values of hydroperoxides and higher induction times concerning the non-crosslinked oil. Finally, the fatty acid profile at this storage time indicated that microcapsules with GA did not have significant changes. In vitro digestion exhibited a reduction in the percentage of bioavailable oil for crosslinked microcapsules, but with no variations in its chemical quality, and an increase in the total polyphenols amount and antioxidant activity.

CONCLUSION

The results obtained demonstrated that the microencapsulation of CO using SPI crosslinked with GA as wall material exerted a very important protective effect since a synergistic effect could be described between the microencapsulation effect and the antioxidant power of GA. © 2023 Society of Chemical Industry.

Porous Microparticles of Corn Starch as Bio-Carriers for Chia Oil

Native corn starch and pretreated corn starch were treated with α-amylase, glucoamylase and mixtures of both to generate starches with high porosity with conserved granular structure. Porous starches were characterized; particle size distribution analysis, nitrogen adsorption-desorption analysis, scanning electron microscopy, water and oil adsorption capacity, differential scanning calorimeter, X-ray diffraction and damaged starch techniques were used. The α-amylase/glucoamylase mixture at the highest dose was the best treatment to generate porous starches with interesting adsorption capacity and granular structure conservation. Selected starches were impregnated with chia oil using a vacuum. Pretreated corn starch modified with the α-amylase/glucoamylase mixture showed no significant differences on impregnation capacity compared with native starch with a similar enzyme treatment. The highest oxidative stability was achieved with pretreated porous starch impregnated with 10 to 25% chia oil, compared with the bulk oil (5.37 to 4.72 and 2.58 h, respectively). Results have demonstrated that vacuum impregnation could be a potential technique for the incorporation of oil in porous structures based on starch and porous starches obtained by enzymatic hydrolysis are a promising material for the incorporation and protection of oils susceptible to oxidation.