Abstract :

Star fruit (Averrhoa carambola L.) is cultivated in Asian and Latin American countries and has high nutritional value due to its content of bioactive compounds, polyphenols, vitamins A and C, minerals, and antioxidant activity. However, its high water content makes it highly perishable, limiting its preservation and commercialization; therefore, it is necessary to develop technological alternatives that extend its shelf life without affecting its organoleptic and nutritional quality. The objective of this study was to evaluate combined power ultrasound-assisted drying technologies for obtaining star fruit flakes as a preservation alternative, analyzing their effect on physicochemical, functional, and sensory attributes. Fruit from the Postgraduate College, Veracruz Campus, was used, and osmotic dehydration (OD) curves were performed at 50 and 60 °Brix, using ultrasound (US) as a pretreatment to convective drying (CS). Drying kinetics were performed at 50 and 60 °C, and total phenolic compounds, antioxidant activity (DPPH and ABTS), oxalic acid, color (ΔE), moisture, total solids, water activity (aw), and texture in the center and periphery were evaluated, in addition to sensory analysis. The DO treatments assisted with ultrasound reached equilibrium in less time. The 60°Brix-CUS-60 °C treatment showed lower final moisture content, while the 60°Brix-CUS-50 °C treatment reached an aw of approximately 0.47, favoring microbiological stability. The 60 °Brix DO treatment with ultrasound and 60 °C surface drying showed lower moisture content and higher total solids content. The 60 °Brix DO treatment without ultrasound and 50 °C surface drying preserved phenols better, reducing oxalic acid by >50% and showing improvements in antioxidant activity. High sensory acceptability was obtained. It is concluded that the DO-US-SC combination is effective in preserving carambola with adequate quality and acceptance.

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Keywords :

convective drying, osmotic dehydration, Oxalic acid, phenolic compounds, Ultrasound

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References :

1. Badui Dergal, S. (2006). Food Chemistry (Fourth ed.). Mexico: PEARSON.
2. Barman, N., & Badwaik, L.S. (2017). Effect of ultrasound and centrifugal force on carambola (Averrhoa carambola L.) slices during osmotic dehydration. Ultrasonics Sonochemistry- ELSEVIER, 37-44.
3. Biswas R., Sayem MAS, Alam M., Sun D. & Afzal HM (2025). Combined Ultrasound and Osmotic Pretreatment as Innovative Preservation Strategies for Enhancing the Quality of Dried Mango Slices. LWT 223(6):117702. https://doi.org/ 1016/j.lwt.2025.117702
4. Bozkir, H.; Ergün, AR; Serdar, E.; Metin, G. & Baysal, T. (2019) Influence of ultrasound and osmotic dehydration pretreatments on drying and quality properties of persimmon fruit. Ultrasound. Sono Chem. 54, 135–141.
5. Camacho MJL, Aguilar TD, Vidales HMA, Jiménez RO, Perdomo F. & Vázquez MR (2025) Ultrasound Strategies for Enhanced Food Dehydration: A Comprehensive Overview. Journal of Future Foods, 1-49 p. doi: https://doi.org/10.1016/j.jfutfo.2025.10.037
6. Ciurzyńska, A.; Kowalska, H.; Czajkowska, K. & Lenart, A., (2016). Osmotic dehydration in production of sustainable and healthy food. In: Trends in Food Science and Technology, 50, pp. 186–192. DOI: https://doi.org/10.1016/j.tifs.2016.01.017
7. Enríquez-Valencia, SA, Salazar-López, NJ, Robles-Sánchez, M., González-Aguilar, GA, Ayala-Zavala, JF, & López-Martínez, LX (2020). Bioactive properties of exotic tropical fruits and their health benefits . ALAN Journal of Food Science and Nutrition , 3(6), 1–13
8. Gamboa-Santos, J., Montilla, A., Cárcel, J., García-Pérez, J., & Villamiel, M. (2012). Application of power ultrasound in the pretreatment and dehydration of vegetables and fruits. Revista Alimentaria, 94-103.
9. Gamboa-Santos, J., Montilla, A., Cárcel, J., Villamiel, M., & García-Pérez, J (2014). Airborne ultrasound application in the convective drying of strawberries, Journal of Food Engineering 128 (2014) 132–139. doi: https:10.1016/ j.jfoodeng. 2013.12.021
10. García, E. 2004. Modifications to the Köppen Climate Classification System. Institute of Geography, National Autonomous University of Mexico. https://librosoa.unam.mx/handle/123456789/1372
11. Guberman, M., Soteras, T., Méndez, I., & Galmarini, MV (2025). Instrumental texture and sensory characteristics of freeze-dried star fruit snacks with added trehalose and sucrose. INNOTEC, (29 Jan-Jun), e681. https://doi.org/10.26461/29.05
12. Moreira, R., & Oliveira, FAR (2008). Osmotic dehydration. In R. Moreira (Ed.), Food dehydration (pp. 1–39). CRC Press.
13. Molyneux, P. (2004). The use of the stable free radical diphenyl-picrylhydrazyl (DPPH) for estimating antioxidant activity. Songklanakarin Journal of Science and Technology, 26 (2), 211–219.
14. Noor Asna, A., & Noriham, A. (2014). ANTIOXIDANT ACTIVITY AND BIOACTIVE COMPONENTS OF OXALIDACEAE FRUIT EXTRACTS. The Malaysian Journal of Analytical Sciences, 116 – 126.
15. Pandiselvam, R.; Tak, Y.; Olum, E.; Sujayasree, OJ; Tekgül, Y.; Çalı¸skan Koç, G.; Kaur, M.; Nayi, P.; Kothakota, A.; Kumar, M. (2022). Advanced osmotic dehydration techniques combined with emerging drying methods for sustainable food production: Impact on bioactive components, texture, color, and sensory properties of food. Texture Stud. 53, 737–762.
16. Pérez Jiménez, J., & Saura-Calixto, F. (2007). Methodology for the evaluation of antioxidant capacity in fruits and vegetables . V Ibero-American Congress on Postharvest Technology and Agro-exports: Technology, quality and safety of fruits and vegetables, Cartagena, Colombia. Postharvest and Refrigeration Group, UPCT
17. Pirone, B., Ochoa, M., Kesseler, A., & De Michelis, A. (2002). Evolution of ascorbic acid concentration during the dehydration process of rosehip fruits (Rosa Eglanteria L.). RIA. Journal of Agricultural Research, 85-98.
18. Re, R., Pellegrini, N., Proteggente, A., Pannala, A., Yang, M., & Rice-Evans, C. (1999). Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radical Biology and Medicine, 26 (9–10), 1231–1237. https://doi.org/10.1016/S0891-5849(98)00315-3
19. Robles Ozuna, LE, & Ochoa Martínez, LA (2012). ULTRASOUND AND ITS APPLICATIONS IN FOOD PROCESSING. Ibero-American Journal of Postharvest Technology, pp. 109-122.
20. SAS Institute Inc. (2011). SAS/STAT® 9.3 User’s Guide . SAS Institute Inc., Cary, NC, USA.
21. Salas-Pérez, L., Moncayo-Luján, M. del R., Borroel-García, VJ, Guzmán-Silos, TL, & Ramírez-Aragón, MG (2022). Phytochemical composition and antioxidant activity in three basil varieties under the effect of different solvents . Mexican Journal of Agricultural Sciences, 13(28), 113–123. https://doi.org/10.29312/remexca.v13i28.3267
22. Secretariat of Commerce and Industrial Development – NMX-F-102-S-1978 . (1978). NMX-F-102-S-1978: Determination of titratable acidity in products made from fruits and vegetables . General Directorate of Standards, Mexico
23. (June 2006). SIDEL. Retrieved from Services and Information for Rural Economic Development: http://www.del.org.bo/info/archivos/frutas_exoticas/capitulo%20IV.pdf
24. Singleton, V.L., & Rossi, J.A., Jr. (1965). Colorimetry of total phenolics with phosphomolybdic–phosphotungstic acid reagents. American Journal of Enology and Viticulture, 16 (3), 144–158.
25. Turkiewicz, I.P., Wojdyło, A. & Tkacz, K. (2020). Osmotic Dehydration as a Pretreatment Modulating the Physicochemical and Biological Properties of the Japanese Quince Fruit Dried by the Convective and Vacuum-Microwave Method. Food Bioprocess Technol 13, 1801–1816 https://doi.org/10.1007/s11947-020-02522-w
26. Udomkun, P., Argyropoulos, D. & Nagle, M. (2018). Changes in microstructure and functional properties of papaya as affected by osmotic pre-treatment combined with freeze-drying. Food Measurement 12, 1028–1037. https://doi.org/10.1007/s11694-018-9718-3