Abstract
This study compared the capacity of propolis extract (PE) and thyme waste extract (TWE) to prevent the oxidation of oil in water (O/W) emulsion, as well as their impact on emulsion apparent viscosity (AV) in the presence of wheat germ and almond oils as lipid phase. For this, central composite design (CCD) and principal component analysis (PCA) were performed. Oxidation process was monitored by evaluating the formation of primary and secondary lipid oxidation products, at the same time the AV behavior was determined evaluating consistency index and flow behavior index. The results revealed that the increase of PE% and TWE% decreases TBARS (Thiobarbituric Acid Reactive Substances) and hydroperoxides formation. Viscosity increases with the rise of TWE% over (0.04%), whereas lower concentrations of PE% decreases it. Those results have been confirmed in the PCA analysis. TWE showed higher resistance to oxidation, although PE was more effective as antioxidant than TWE.
Funding source: Fundação para a Ciência e a Tecnologia
Acknowledgments
The authors wish to acknowledge the financial support provided by the Fundação para a Ciência e a Tecnologia—FCT; Portugal, under the projects the Project UIDB/05183/2020 and UID/MAR/00350/2013.
Conflicts of interest: The authors declare that they have no conflicts of interest.
References
1. Nikovska K. Study of olive oil-in-water emulsions with protein emulsifiers. Emir J Food Agric 2012;24:17–24. https://doi.org/10.1002/ejlt.201100321.Search in Google Scholar
2. Linke C, Drusch S. Pickering emulsions in foods – opportunities and limitations. Crit Rev Food Sci Nut 2018;58:1971–85. https://doi.org/10.1080/10408398.2017.1290578.Search in Google Scholar
3. Yamaki K, Taneda S, Yanagisawa R, Inoue K, Takano H, Yoshino S. Enhancement of allergic responses in vivo and in vitro by butylated hydroxytoluene. Toxicol Appl Pharmacol 2007;223:164–72. https://doi.org/10.1016/j.taap.2007.05.007.Search in Google Scholar
4. Nieva-Echevarría B, Manzanos MJ, Goicoechea E, Guillén MD. 2,6-Di-tert-butyl-hydroxytoluene and its metabolites in foods. Compr Rev Food Sci Food S 2015;14:7–80. https://doi.org/10.1111/1541-4337.12121.Search in Google Scholar
5. El-Guendouz S, Aazza S, Lyoussi B, Majdoub N, Bankova V, et al. Effect of poplar-type propolis on oxidative stability and rheological properties of O/W emulsions. Saudi Pharm J 2018;26:1073–82. https://doi.org/10.1016/j.jsps.2018.05.017.Search in Google Scholar
6. El-Guendouz S, Aazza S, Dandlen SA, Majdoub N, Lyoussi B, et al. Antioxidant activity of thyme waste extract in O/W emulsions. Antioxidants 2019;8:243. https://doi.org/10.3390/antiox8080243.Search in Google Scholar
© 2020 Walter de Gruyter GmbH, Berlin/Boston
