Lipid Oxidation in Algae Oil-in-Water Emulsions Stabilized by Bovine and Caprine Caseins

Abstract

Caseins (alpha(s1)-, alpha(s2)-, and beta-casein) are phosphoproteins that are capable of binding transition metals and scavenging free radicals; this property makes them good candidates to be used as natural antioxidants in oil-in-water emulsions. Caprine casein exhibits variability in alpha(s1)-casein content generated by genetic polymorphism. This variability in composition could lead to altered antioxidant properties. Thus, the ability of two caprine caseins differing in alpha(s1)-casein content to inhibit lipid oxidation in algae oil-in-water emulsions at 5% oil was investigated and compared to bovine caseinate. All caseins inhibited the formation of lipid oxidation at pH 7.0 as determined by lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS). However, caprine caseins were in general more effective inhibitors of lipid oxidation than the bovine caseins, which may be attributed to their altered casein amino acid content and/or metal binding capabilities. The combination of the carotenoids with bovine and caprine caseins was highly effective at repressing oxidation leading to the speculation that the caseins may inhibit the loss of the carotenoids and/or react with and enhance the carotenoid activity; again some differences between bovine and caprine caseins were observed with caprine caseins being slightly more effective in the presence of carotenoids.

Cross‐linking of bovine and caprine caseins by microbial transglutaminase and their use as microencapsulating agents for n‐3 fatty acids

“…One factor contributing to the differences in antioxidant activity of the bovine and caprine caseins in algae oil‐in‐water emulsions is the different profile of caseins (Mora‐Gutierrez et al ., ). Bovine and caprine caseins both contain the four main casein classes: α s1 ‐, α s2 ‐, β‐ and κ‐casein, but the level of α s1 ‐casein in caprine caseins isolated from the milks of American‐bred, French‐Alpine goats ranges from high to low (Mora‐Gutierrez et al ., ).…”

“…Because of the compositional differences, these milk proteins exhibit major differences ( P < 0.05) in terms of the content of potential antioxidative amino acids histidine, methionine, phenylalanine, proline, tryptophan and tyrosine (Fig. ); curiously, these differences favour the bovine casein, which in previous studies was less effective in suppressing lipid oxidation (Mora‐Gutierrez et al ., ). It was expected that a high content of antioxidative amino acids in the caseins would lead to a decrease in lipid oxidation.…”

“…The results by Mora‐Gutierrez et al . () were largely explained on the basis of interfacial phenomena having a significant effect on oxidative stability of lipid systems. The mechanism of this process may be related to the affinity of β‐casein towards the oil‐in‐water interfaces in emulsions, that is, β‐casein was adsorbed and formed a viscoelastic film at the oil‐in‐water interface of the emulsion.…”

“…It was expected that a high content of antioxidative amino acids in the caseins would lead to a decrease in lipid oxidation. Instead, a high content of the β‐casein fraction was correlated with improved oxidative stability of algae oil‐in‐water emulsions (Mora‐Gutierrez et al ., ). The results by Mora‐Gutierrez et al .…”

Algal Supply System Design - Harmonized Version

“…Hydroperoxide, an initial product of lipid oxidation degrades causing volatiles like aldehydes and alcohols that cause rancidity (Kim et al 2007;Min and Boff 2002). Oxidation of lipids can occur when exposed to light, air, transition metals, and elevated temperatures (Harris 2007;Mora-Gutierrez et al 2010). A study on the stability of biodiesel from sunflower oil demonstrated that increases were measured in acid and peroxide content for storage temperatures of 50°C and in the presence of light (Du Pleiss et al 1985).…”