Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Feb 27:2020:8380461.
doi: 10.1155/2020/8380461. eCollection 2020.

Assessment of Enzymatic Browning and Evaluation of Antibrowning Methods on Dates

Mariam Al-Amrani  1 , Ahmed Al-Alawi  2 , Insaaf Al-Marhobi  2
Affiliations

Assessment of Enzymatic Browning and Evaluation of Antibrowning Methods on Dates

Mariam Al-Amrani et al. Int J Food Sci. .

Abstract

Dates' color is known to play a crucial role in determining the value and quality of the fruit. The color changes from the natural accepted golden color to unfavorable dark brown color during storage. In this study, the effect of different color preservation methods (modified atmosphere packaging, cold storage (4°C), sulfur dioxide gas (SO2), and blanching) and its relation to darkening due to action of the browning enzymes and melanin production were investigated. Polyphenol oxidase was shown to be active in all treatments except the samples treated with SO2 gas and steam blanching for ten minutes. Likewise, peroxidase activity showed a similar trend in all samples, but a decrease in activity was observed in sulfated samples and total inactivation in steam blanching for ten minutes. Moreover, sulfated samples have shown improvement in color compared to all other treatments, whereas the steamed samples showed the highest color deterioration. Concurrently, melanin content increased in all samples over the period of storage except in the sulfated samples. FTIR analyses of dates' melanin have revealed similar structural feature to the reference melanin; however, some differences were noticed in the regions 2850-2950 cm-1 and 1690-1705 cm-1 which indicated major structural difference between the two melanin samples. More work is suggested to reveal structural and functional properties of dates' melanin.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no conflicts of interest.

Figures

Figure 1
Figure 1
Effect of different preservation methods on polyphenol oxidase activity during storage. Control (♦), SO2 (●), cold storage (▲), blanching three minutes (■), modified atmosphere packaging (╳), and blanching ten minutes (∗). Same letter indicates no statistical differences between groups.
Figure 2
Figure 2
Effect of different preservation methods on peroxidase activity during storage. Control (♦), SO2 (●), cold storage (▲), blanching three minutes (■), modified atmosphere packaging (╳), and blanching ten minutes (∗). Same letter indicates no statistical differences between groups.
Figure 3
Figure 3
Hue index for different preservation methods during 100 days of storage at room temperature (P value < 0.05). Control (♦), SO2 (●), cold storage (▲), blanching three minutes (■), modified atmosphere packaging (╳), blanching ten minutes (∗). Same letter indicates no statistical differences between groups.
Figure 4
Figure 4
Melanin concentration (%) obtained by the different preservation methods during storage (P value < 0.05). Control (♦), SO2 (●), cold storage (▲), blanching three minutes (■), and modified atmosphere packaging (╳). Same letter indicates no statistical differences between groups.
Figure 5
Figure 5
FTIR spectra of partially purified dates' melanin (B) and reference melanin (A).
See this image and copyright information in PMC

References

    1. Al-Yahyai R., Khan M. M. Date palm status and perspective in Oman. In: al-Khayri J. M., Jain S. M., Johnson D. V., editors. Date Palm Genetic Resources and Utilization. Dordrecht: Springer; 2015. pp. 207–240. - DOI
    1. Ghnimi S., Umer S., Karim A., Kamal-Eldin A. Date fruit (Phoenix dactylifera L.): An underutilized food seeking industrial valorization. NFS Journal. 2017;6:1–10. doi: 10.1016/j.nfs.2016.12.001. - DOI
    1. Hazbavi I., Khoshtaghaza M. H., Mostaan A., Banakar A. Effect of postharvest hot-water and heat treatment on quality of date palm (cv. Stamaran) Journal of the Saudi Society of Agricultural Sciences. 2015;14(2):153–159. doi: 10.1016/j.jssas.2013.10.003. - DOI
    1. Al-Yahyai R., Al-Khanjari S. Biodiversity of date palm in the Sultanate of Oman. African Journal of Agricultural Research. 2008;3(6):389–395.
    1. Ahlam R., Cheb M., Mohammed K., Mami Y. Impact of heat treatment on polyphenol oxidase and peroxidase action in Algerian stored dates. International Journal of Agricultural Sciences. 2015;5(3):517–520.

LinkOut - more resources