Browsing by Person "Klinger, Evelyn"

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Interactions between lipid oxidation and anthocyanins from black carrots in ω-3 fatty acid-rich flaxseed oil-in-water emulsions
(2024) Klinger, Evelyn; Salminen, Hanna; Bause, Karola; Weiss, Jochen
The application of anthocyanins as red colorants in lipid-containing foods such as oil-in-water emulsions is challenging due to their ability to act as antioxidants and their instability under various environmental conditions. In this study, we investigated the kinetics of black carrot anthocyanin degradation and the subsequent color loss influenced by lipid oxidation reactions in 1% ( w/w ) flaxseed oil-in-water emulsions stabilized by 0.1% ( w/w ) sodium dodecyl sulfate (SDS) at pH 2 upon storage at 35 °C for ten days under light and in the dark. Oxidatively stable Miglyol oil-in-water emulsions and SDS solutions were used as reference. The results showed simultaneous formation of lipid hydroperoxides and degradation of anthocyanins. The addition of anthocyanins decreased lipid hydroperoxide formation, confirming the antioxidant activity of anthocyanins through radical scavenging mechanism. The kinetic modelling of lipid oxidation and anthocyanin degradation are particularly important for estimating color stability in colored emulsion-based food systems such as dairy or non-dairy milk or yoghurt drinks.
Stability of anthocyanin extracts from chokeberry, grape, hibiscus, and purple sweet potato in ω-3-fatty acid rich oil-in-water emulsions
(2024) Klinger, Evelyn; Salminen, Hanna; Bause, Karola; Weiss, Jochen
The food industry is actively investigating the stability of natural red pigments to replace artificial food colorants from all food applications in the near future. In this study, the stability of coloring extracts from chokeberry, grape, hibiscus, and purple sweet potato was investigated in ω-3 fatty acid-rich flaxseed oil-in-water emulsion during storage. The red color of the oil-in-water emulsions faded within 4 days, indicating that the anthocyanin extracts were susceptible to lipid oxidation reactions of the ω-3 fatty acids. The color stability varied between all used extract sources: The chokeberry (degradation constant k = 19.6 h−1) and grape (k = 15.2 h−1) extracts showed similar degradation kinetics, whereas purple sweet potato extract (k = 10.7 h−1) degraded significantly slower, and hibiscus extract (k = 110.2 h−1) significantly faster. The differences can be explained by the different anthocyanins contained in the plant extract, especially by the proportion of acylated anthocyanins.