Formation of Antioxidant Multilayered Coatings for
the Prevention of Lipid and Protein Oxidation in Oil-in-Water Emulsions: Lycium barbarum Polysaccharides and Whey Proteins
posted on 2021-12-21, 07:29authored byLi Tian, Shulin Zhang, Jianhua Yi, Zhenbao Zhu, Meili Li, Eric Andrew Decker, David Julian McClements
The
impact of Lycium barbarum polysaccharides
(LBPs) on the physical and chemical stability of oil-in-water emulsions
coated by a whey protein isolate (WPI) was investigated. At pH 3.0,
the anionic LBP (0.2–0.6 wt %) molecules were electrostatically
deposited onto the cationic surfaces of the WPI-coated oil droplets,
leading to the formation of stable multilayered emulsions containing
WPI-/LBP-coated oil droplets. However, increasing the LBP concentration
to 0.8 wt % led to oil droplet aggregation, which was attributed to
charge neutralization, bridging flocculation, and/or depletion flocculation.
For subsequent experiments, a low (0.2%) and an intermediate (0.6%)
LBP dose was used to prepare the secondary emulsions, and then their
physical and oxidative stability was studied during 8 days of storage
at 37 °C. The presence of the multilayer WPI/LBP coatings around
the oil droplets inhibited lipid oxidation (reduced levels of lipid
hydroperoxides and 2-thiobarbituric acid-reactive substances), as
well as protein oxidation (reduced levels of carbonyl formation, sulfhydryl
consumption, molecular weight modifications, intrinsic fluorescence
loss, and Schiff-base fluorescence gain). The antioxidant effects
of the multilayer coatings were greater at the higher LBP concentration.
These results suggest that LBP, a natural plant-based polysaccharide
isolated from a traditional Chinese medicine, can be used to improve
the quality of emulsion-based foods. However, the level used should
be optimized to ensure good physical and oxidative stability of the
emulsions.