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. 2025 Jun 30:12:1619072.
doi: 10.3389/fnut.2025.1619072. eCollection 2025.

Effects of screw-pressing temperature on the functional properties and structural characteristics of apricot (Prunus armeniaca L.) kernel protein isolates

Li Zhang  1 , Hongyu Wu  1 , Mengshi Wang  2 , Xianjin Zhou  3 , Bayinkexike  4 , Ruiguo Cui  1 , Lijun Song  2 , Fengjuan Liu  5
Affiliations

Effects of screw-pressing temperature on the functional properties and structural characteristics of apricot (Prunus armeniaca L.) kernel protein isolates

Li Zhang et al. Front Nutr. .

Abstract

This study aimed to investigate the effect of screw-pressing temperature on the quality of apricot kernel protein isolates (API). The API values at different screw-pressing temperatures (40-200°C) were obtained, and the functional and structural properties of different API samples were comparatively studied. The results revealed that the total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant activities (DPPH and FRAP assays) increased significantly with increasing temperature. High-temperature pressing also increased the surface hydrophobicity and emulsification of API. SDS-PAGE confirmed the preservation of the primary structure of API, with molecular weights ranging from 13 to 20 kDa and 36-56 kDa. Circular dichroism (CD) spectroscopy analysis revealed that the α-helix content increased (by 4-8%) and the β-sheet content decreased (by 2-5%) when the samples were pressed at high temperatures. The decrease in fluorescence intensity and the fluorescence spectral shift indicated changes in the tertiary structure. Multivariate statistical analysis revealed that the antioxidant activities were positively correlated to protein carbonyls, free sulfhydryl groups, surface hydrophobicity, TPC, and TFC. Mechanistically, thermally-induced protein conformational changes and surface hydrophobicity modulation drove the observed enhancements in functional properties. These findings will collectively serve as a theoretical basis for the efficient preparation and application of API.

Keywords: apricot kernel protein isolate; functional properties; multivariate statistical analysis; screw-pressing temperatures; structural characteristics.

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Conflict of interest statement

XZ was employed by Bazhoujiamu Agroscience Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
The functional characteristics of API at different screw-pressing temperatures. (A) NSI; (B) WHC and OHC; (C) EAI and ESI; (D) Foaming properties and stability. NSI, Nitrogen soluble index; WHC, Water-holding capacity; OHC, Oil-holding capacity; EAI, Emulsifying activity index; ESI, Emulsion stability index.
Figure 2
Figure 2
Particle size distribution (A) and zeta-potential (B) of different API types.
Figure 3
Figure 3
SDS-PAGE profiles of different API types.
Figure 4
Figure 4
Effect of different screw-pressing temperatures on the structural characteristics of API. (A) CD spectroscopy, (B) Secondary structure content, (C) Fluorescence spectra.
Figure 5
Figure 5
The appearance and SEM images of the API samples obtained at different screw-pressing temperatures. (A-E) Respectively represent API-40, API-80, API-120, API-160, and API-200.
Figure 6
Figure 6
Principal component analysis (A), correlation analysis (B), and hierarchical cluster analysis (C) of different API types.
See this image and copyright information in PMC

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References

    1. Kshirsagar HH, Fajer P, Sharma GM, Roux KH, Sathe SK. Biochemical and spectroscopic characterization of almond and cashew nut seed 11S Legumins, Amandin and Anacardein. J Agric Food Chem. (2011) 59:386–93. doi: 10.1021/jf1030899 - DOI - PubMed
    1. Wolf WJ, Sathe SK. Ultracentrifugal and polyacrylamide gel electrophoretic studies of extractability and stability of almond meal proteins. J Sci Food Agric. (1998) 78:511–21. doi: 10.1002/(sici)1097-0010(199812)78:4<511::aid-jsfa148>3.0.co;2-x - DOI
    1. Zhu X, Zhang X, Wang Z, Ren F, Zhu X, Chen B, et al. Screening and preparation of highly active antioxidant peptides of apricot and their inhibitory effect on ultraviolet radiation. Food Chem. (2025) 463:141336. doi: 10.1016/j.foodchem.2024.141336, PMID: - DOI - PubMed
    1. Pawar KR, Nema PK. Apricot kernel characterization, oil extraction, and its utilization: a review. Food Sci Biotechnol. (2023) 32:249–63. doi: 10.1007/s10068-022-01228-3, PMID: - DOI - PMC - PubMed
    1. Akhone MA, Bains A, Tosif MM, Chawla P, Fogarasi M, Fogarasi S. Apricot kernel: bioactivity, characterization, applications, and health attributes. Food Secur. (2022) 11:2184. doi: 10.3390/foods11152184, PMID: - DOI - PMC - PubMed

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