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. 2025 Jul 30;14(15):2686.
doi: 10.3390/foods14152686.

Optimization of Anthocyanin Extraction from Purple Sweet Potato Peel (Ipomea batata) Using Sonotrode Ultrasound-Assisted Extraction

Raquel Lucas-González  1 , Mirian Pateiro  2 , Rubén Domínguez-Valencia  2 , Celia Carrillo  3 , José M Lorenzo  2   4
Affiliations

Optimization of Anthocyanin Extraction from Purple Sweet Potato Peel (Ipomea batata) Using Sonotrode Ultrasound-Assisted Extraction

Raquel Lucas-González et al. Foods. .

Abstract

Sweet potato is a valuable root due to its nutritional benefits, health-promoting properties, and technological applications. The peel, often discarded during food processing, can be employed in the food industry, supporting a circular economy. Purple sweet potato peel (PSPP) is rich in anthocyanins, which can be used as natural colourants and antioxidants. Optimising their extraction can enhance yield and reduce costs. The current work aimed to optimize anthocyanin and antioxidant recovery from PSPP using a Box-Behnken design and sonotrode ultrasound-assisted extraction (sonotrode-UAE). Three independent variables were analysed: extraction time (2-6 min), ethanol concentration (35-85%), and liquid-to-solid ratio (10-30 mL/g). The dependent variables included total monomeric anthocyanin content (TMAC), individual anthocyanins, and antioxidant activity. TMAC in 15 extracts ranged from 0.16 to 2.66 mg/g PSPP. Peonidin-3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside was the predominant anthocyanin. Among four antioxidant assays, Ferric-reducing antioxidant power (FRAP) showed the highest value. Ethanol concentration significantly influenced anthocyanin and antioxidant recovery (p < 0.05). The model demonstrated adequacy based on the coefficient of determination and variation. Optimal extraction conditions were 6 min with 60% ethanol at a 30 mL/g ratio. Predicted values were validated experimentally (coefficient of variation <10%). In conclusion, PSPP is a promising matrix for obtaining anthocyanin-rich extracts with antioxidant activity, offering potential applications in the food industry.

Keywords: RSM-BBD; acylated anthocyanins; antioxidant activity; co-products; pigments; valorisation.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Image of purple sweet potato. (a) Unpeeled, (b) peeled, (c) fresh, (d) dehydrated, (e) milled and sieved (<1 mm).
Figure 2
Figure 2
Schematic representation of anthocyanin extraction process using sonotrode-UAE (created with BioRender).
Figure 3
Figure 3
Contour plot as function of extraction time (min), liquid-to-solid ratio (mL/g), and ethanol concentration (%).
See this image and copyright information in PMC

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References

    1. Grant K.R., Gallardo R.K., McCluskey J.J. Consumer Preferences for Foods with Clean Labels and New Food Technologies. Agribusiness. 2021;37:764–781. doi: 10.1002/agr.21705. - DOI
    1. Asioli D., Aschemann-Witzel J., Caputo V., Vecchio R., Annunziata A., Næs T., Varela P. Making Sense of the “Clean Label” Trends: A Review of Consumer Food Choice Behavior and Discussion of Industry Implications. Food Res. Int. 2017;99:58–71. doi: 10.1016/j.foodres.2017.07.022. - DOI - PubMed
    1. Paola Floridas-Galán J., Paredes-Concepción P. Bioactive Compounds from Agroindustrial Byproducts and Their Applications: From Traditional Methods to Green Technologies. Sci. Agropecu. 2024;15:461–476. doi: 10.17268/sci.agropecu.2024.034. - DOI
    1. Frosi I., Balduzzi A., Moretto G., Colombo R., Papetti A. Towards Valorization of Food-Waste-Derived Pectin: Recent Advances on Their Characterization and Application. Molecules. 2023;28:6390. doi: 10.3390/molecules28176390. - DOI - PMC - PubMed
    1. Di Maro M., Gargiulo L., Gomez d’Ayala G., Duraccio D. Exploring Antimicrobial Compounds from Agri-Food Wastes for Sustainable Applications. Int. J. Mol. Sci. 2024;25:13171. doi: 10.3390/ijms252313171. - DOI - PMC - PubMed

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