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Akazawa T, Itami H, Furumoto T, Nozaki C, Koike H, Iritani S, Amimoto N, Ogawa M. Impact of an Olive Leaf Polyphenol 3,4-DHPEA-EDA on Physical Properties of Food Protein Gels. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:14250-14258. [PMID: 34730369 DOI: 10.1021/acs.jafc.1c04661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A cold-water extract of olive leaves (Olea europaea L.) is useful as a texture-improving agent for food protein gels. In this work, the compound contributing to the improvement of gel properties was investigated by using the egg white gel (EWG) as a model for food protein gels. Adding 1.0% (w/v) cold-water extract (OLEx) greatly improved the elasticity (2.1 times), viscosity (4.5 times), and breaking stress (1.4 times) of the EWG. Chemical analyses of the protein revealed that the enhancement of physical properties by OLEx was attributed to protein cross-linking activity of polyphenols. LC/MS and NMR analyses indicated that a major protein cross-linker is the dialdehydic form of demethoxycarbonylelenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA), which is an aglycone derived from oleuropein, a major polyphenol of olive leaves. These results suggest that 3,4-DHPEA-EDA generated by cold-water extraction from the leaf improves the physical properties, that is, texture, of protein gels.
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Affiliation(s)
- Takashi Akazawa
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan
- Department of Food Management, School of Food, Agricultural and Environmental Sciences, Miyagi University, Sendai, Miyagi 982-0215, Japan
| | - Hikaru Itami
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan
| | - Toshio Furumoto
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan
| | - Chie Nozaki
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan
| | - Hiroyuki Koike
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan
| | - Saika Iritani
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan
| | - Naoyuki Amimoto
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan
| | - Masahiro Ogawa
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki, Kagawa 761-0795, Japan
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