Structurally modified pectin for targeted lipid antioxidant capacity in linseed/sunflower oil-in-water emulsions

Abstract

The present work explored the lipid antioxidant capacity of citrus pectin addition to 5%(w/v) linseed/sunflower oil emulsions stabilized with 0.5%(w/v) Tween 80, as affected by pectin molecular characteristics. The peroxide formation in the emulsions, containing tailored pectin structures, was studied during two weeks of storage at 35°C. Low demethylesterified pectin (≤33%) exhibited a higher antioxidant capacity than high demethylesterified pectin (≥58%), probably due to its higher chelating capacity of pro-oxidative metal ions (Fe), whereas the distribution pattern of methylesters along the pectin chain only slightly affected the antioxidant capacity. Nevertheless, pectin addition to the emulsions caused emulsion destabilization probably due to depletion or bridging effect, independent of the pectin structural characteristics. These results evidence the potential of structurally modified citrus pectin as a natural antioxidant in emulsions. However, optimal conditions for emulsion stability should be carefully selected.

Influence of Pectin Structural Properties on Interactions with Divalent Cations and Its Associated Functionalities

“…A further increase in pectin concentration from 0.05 to 0.1% (w/v) did not lead to a clear difference in the lipid antioxidant capacity of LM or HM pectin (Chen et al., ), whereas according to Celus et al. (), a further increase in citrus pectin concentration from 0.1 to 1 % (w/v) in the aqueous phase of linseed/sunflower o/w emulsions (5% w/v) stabilized by Tween 80 (0.5% w/v) was accompanied by a significant decrease in lipid oxidation. Despite the fact that emulsion destabilization was observed for the o/w emulsions containing 1% pectin (w/v), it can be suggested that increasing pectin concentration results in a decrease in lipid oxidation, given the higher number of negatively charged carboxyl groups present to bind Fe 2+ .…”

“…Despite the fact that several pectin structural properties, such as DM, DB, DP, or DAc, have been suggested to direct its divalent cation‐chelating capacity and, thus, its lipid antioxidant capacity, only the effect of pectin DM and DB abs on the oxidative stability of o/w emulsions has been reported in the literature. The lipid antioxidant capacity of pectin is reported to be more pronounced at low DM, due to the higher number of negative charges, which is associated with a higher Fe 2+ ‐binding capacity (Celus et al., ; Chen et al., ). In contrast, pectin DB abs reportedly does not have a large influence on its lipid antioxidant capacity (Celus et al., ).…”

“…The lipid antioxidant capacity of pectin is reported to be more pronounced at low DM, due to the higher number of negative charges, which is associated with a higher Fe 2+ ‐binding capacity (Celus et al., ; Chen et al., ). In contrast, pectin DB abs reportedly does not have a large influence on its lipid antioxidant capacity (Celus et al., ). In addition to the pectin molecular structure, extrinsic factors such as the pectin concentration and pH are reported to influence lipid oxidation.…”

“…To date, EDTA is widely used for this purpose. However, with the growing demand to replace artificial additives by natural alternatives, the ability of anionic natural polysaccharides such as pectin to retard lipid oxidation by binding Fe 2+ has been explored by a few researchers (Celus et al, 2018c;Chen, McClements, & Decker, 2010;Huang, Lu, Wang, & Wu, 2011;Shimada, Okada, Matsuo, & Yoshioka, 1996;Xu, Liu, Luo, Liu, & McClements, 2017). Although Cu 2+ is also known to accelerate lipid oxidation (Schaich, Shahidi, Zhong, & Eskin, 2013), the interaction between pectin and Fe 2+ is considered more important here, given that Fe 2+ is more (naturally) abundant in food products (Katsuda, McClements, Miglioranza, & Decker, 2008).…”

Synthesis, physicochemical properties, and health aspects of structured lipids: A review

“…But the oxidative stability could be restored when the proteins were added back, mainly due to iron‐binding capacity of the unabsorbed proteins. Addition of other types of biopolymers in O/W emulsions, which are not intended to be used as emulsifiers, have also been reported to exhibit antioxidant capacity such as casein (Chen et al., ), citrus pectin (Celus et al., ), and sodium alginate (Salvia‐Trujillo, Decker, & Mcclements, ), to name a few. In addition, a recent work by Johnson, Inchingolo, and Decker () has reported that oxygen content in a fish oil‐in‐water system could be reduced by ≥95% by using commercially accessible oxygen scavenging packaging, which significantly improved the emulsion oxidative stability.…”