Development of food-grade Pickering oil-in-water emulsions: Tailoring functionality using mixtures of cellulose nanocrystals and lauric arginate.

In this study, we investigated the tailoring of food emulsions using interactions between rice bran cellulose nanocrystals (CNCs) and lauric arginate (LAE), which is food-grade cationic surfactant. Complexes of anionic CNCs and cationic LAE (CNCs/LAE) were formed through electrostatic attraction which were characterized using isothermal titration calorimetry (ITC), turbidity, and zeta-potential measurements. The saturation complexes could be formed at ratios of 1:2 (w/w) CNCs-to-LAE. Furthermore, the physical and oxidative stability of oil-in-water emulsions containing lipid droplets coated by CNCs/LAE complexes was determined. Electrostatic complexes formed from 0.02% CNCs and 0.1% LAE produced stable Pickering emulsions that were resistant to droplet coalescence. It was also exhibited that 0.02% CNCs and 0.1% LAE complexes stabilized-emulsions was able to extend the lag phase to 20 days for lipid hydroperoxide and to 14 days for hexanal production. This study shows that food-grade Pickering emulsions with good stability can be produced by CNCs with LAE complexes.

Impact of Phospholipid-Tocopherol Combinations and Enzyme-Modified Lecithin on the Oxidative Stability of Bulk Oil.

Phosphatidylethanolamine (PE) and phosphatidylserine (PS) have been shown to increase the antioxidant activity of α-tocopherol. This study investigated the ability of PE or PS to increase the antioxidant activity of different tocopherol homologues in bulk oil. In addition, the ability of a phospholipase-D-modified lecithin (high in PE) to increase the activity of α-tocopherol was determined. Results showed that PE was much more effective than PS at increasing the activity of the tocopherol homologues. The combination of mixed tocopherols with PE presented the greatest increase in antioxidant activity, with hydroperoxides and hexanal lag phases increasing 54 and 53 days compared to the mixed tocopherols alone. Phospholipase-D-modified lecithin increased the antioxidant activity of α-tocopherol in stripped bulk oil as well as a commercially refined oil with no added tocopherols. The study indicates that PE is a powerful tool to increase the antioxidant activity of tocopherols in bulk oil and that modification of lecithin to increase the PE concentration could be a commercially viable option to functionalize lecithin, so that its ability to inhibit lipid oxidation increases in bulk oils.

Digital image colorimetric analysis for evaluating lipid oxidation in oils and its emulsion.

Optical analytical images were captured by a digital camera, and lipid peroxidation was monitored using colorimetric determination. The Image-J method was shown to have comparable accuracy to the conventional titration (American Oil Chemists' Society) and UV-Vis spectroscopic methods. Over the PV range 3-14 meq.O2/kg, a good correlation (R2 = 0.9836) was found between the proposed method and UV-Vis method with an SD of ±0.0339 meq.O2/kg. The range and accuracy of detection were determined from the changes in the Image-J intensity values. At equivalent PV, the limit of detection was 0.175 meq.O2/kg and the limit of quantitation was 0.35 meq.O2/kg. The proposed Image-J application can be used to develop fast and portable devices for monitoring peroxide values. These have potential applications in quality control for small-scale farmers and small and medium enterprises.