Alim25628 Vol. 24 No. 3 (2025)

Vol. 24, No. 3 (2025), Alim25628 https://doi.org/10.24275/rmiq/Alim25628

Impact of modulation of solar irradiance on spinach drying and its effects on bioactive compounds and quality

Authors

D. P. García-Moreira, I. Moreno, L. Delgadillo-Ruiz, E. C. López-Vidaña

Abstract

This study investigated spinach's drying kinetics, colorimetric degradation, Antioxidant Capacity and Total Fenolic Content using two solar dryers: Cylindrical Solar Dryer and a novel Solar Dryer with Dynamic Irradiance Control. The parameters monitored were moisture content, temperature, relative humidity, solar irradiance, and CIELa*b* color coordinates. The Solar Dryer with Dynamic Irradiance Control achieved a final moisture content of 0.030 g H₂O/g d.m. in 220 minutes, while the Cylindrical Solar Dryer reached equilibrium in 160 minutes. The Solar Dryer with Dynamic Irradiance Control exhibited a maximum drying rate of 0.1346 g H₂O/g d.m. min⁻¹ and demonstrated superior control over drying conditions, mitigating thermal losses and preserving color quality. The Cylindrical Solar Dryer showed faster drying but greater color degradation, particularly in the b* coordinate. Chemical analyses revealed that SDIC-dried spinach retained significantly higher antioxidant activity (1686.34 ± 42.98 µmol Eq Trolox/g d.w. by ABTS) compared to CSD (1419.00 ± 50.79), despite CSD showing elevated total phenolics (62.541 ± 1.76 mg GAE/100 g) likely due to oxidative degradation. These findings highlight SDIC’s potential to balance drying efficiency with phytochemical preservation in photosensitive crops. These findings highlight the potential of the Solar Dryer with Dynamic Irradiance Control for preserving the quality of photosensitive crops like spinach, offering a sustainable solution for food preservation in semi-arid regions.

Keywords

BFood Colorimetry, Solar Drying, Solar Irradiance modulator, Spinach drying, PDLC applied in solar drying.

References
Guiné, R. P. (2018). The Drying of Foods and Its Effect on the. International Journal of Food Engineering Physical-Chemical, Sensorial and Nutritional Properties, 4(2), 93-100. Álvarez - Parrilla, E., De la Rosa, L. A., Martínez, N. R., & González, G. A. (2007). Total phenols and antioxidant activity of commercial and wild mushrooms from chihuahua, Mexico fenoles totalesy capacidad antioxidante de hongos comercialesy silvestres De Chihuahua, México. CYTA-Journal of Food, 5(5), 329-334. Amarowicz, R., & Pegg, R. B. (2008). Legumes as a source of natural antioxidants. European Journal of Lipid Science and Technology, 110(10), 865-878. Aravindh, M. A., & Sreekumar, A. (2015). Solar drying—a sustainable way of food processing. In Energy sustainability through green energy (pp. 27-46). Sharma: Springer India. Benzie, I. F., & Strain, J. J. (1996). The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant power”: The FRAP assay. Analytical Biochemistry, 239(1), 70-76. Chew, Y. L., Lim, Y. Y., Omar, M., & Khoo, K. S. (2008). Antioxidant activity of three edible seaweeds from two areas in South East Asia. LWT-Food Science and Technology, 41(6), 1067-1072. FAOSTAT. (2024, December 20 ). Food Agriculture Organization of the United Nations. Retrieved January 21, 2025, from https://www.fao.org/faostat/en/#data/QCL Galla, N. R., Pamidighantam, P. R., Karakala, B., Gurusiddaiah, M. R., & Akula, S. (2017). Nutritional, textural and sensory qualitu of biscuits supplemented with spinach (Spinacia oleracea L.). International Journal of Gastronomy and Food Science, 7, 20-26. García-Moreira, D. P., López-Vidaña, E. C., Moreno, I., & Delgadillo-Ruiz, L. (2025). Impact of Spectral Irradiance Control on Bioactive Compounds and Color Preservation in Solar Dried Papaya. Processes, 13, 2311. García-Moreira, D. P., Moreno, I., Irigoyen-Campuzano, J., Martín-Domínguez, I., García-Valladares, O., & López-Vidaña, E. C. (2024). Effect of convective drying on color, water activity, and browning index of peach slices. Revista Mexicana de Ingeniería Química, 23(1). Gutiérrez-Martínez, S., Hernández-Varela, J., Chanona-Pérez, J., Méndez-Méndez, J., González-Martínez, H., Perea-Flores, M., . . . González-Victoriano, L. (2024). Study of drying, thermal, shrinkage, and color kinetics using digital and thermographic imaging of potato slices under real-time convective drying. Revista Mexicana de Ingeniería Química, 23(3), Alim24322. Kaur, A., Kaur, D., Oberoi, D., Gill, B., & Sogi, D. (2008). Effect of dehydration on physicochemical properties of mustard, mint and spinach. Journal of Food Processing and Preservation, 32, 103-116. Krokida, M. K., Tsami, E., & Maroulis, Z. B. (1998). KINETICS ON COLOR CHANGES DURING DRYING OF SOME FRUITS AND VEGETABLES. Drying Technology: An International Journal, 3(5), 667-685. Manzoor, M. F., Ahmed, Z., Ahmad, N., Aadil, R. M., Rahaman, A., Roobab, U., . . . Siddeeg, A. (2020). Novelprocessing techniques and spinach juice: Quality and safety im-provements. Journal of Food Science, 85(4), 1018-1026. Mulokozi , G., & Svanber , U. (2003). Effect of Traditional Open Sun-Drying and Solar Cabinet Drying on Carotene Content and Vitamin A Activity of Green Leafy Vegetables. Plant Foods for Human Nutrition, 58(3), 1-15. Nahar, N. M. (2009). Processing of vegetables in solar dryer in arid areas. International Solar Food Processing Conference. Indore, India. Pal, A. A., & Acedo Jr, A. L. (2022). Quality profile of different vegetables dried using simple solardryers . Int. J. Postharvest Technology and Innovation, 8(4), 313-327. S., G., Brat, P., Alter, P., & Amiot, J. (2005). Rapid determination of polyphenols and vitamin C in plant-derived products. Journal of Agricultural and Food Chemistry, 53, 1370-1373. Spence , C. (2015). On the psychological impact of food colour. Flavour, 4(21). doi:https://doi.org/10.1186/s13411-015-0031-3 Vargas, L., Kapoor, R., Nemzer, B., & Feng, H. (2022). Application of different drying methods for evaluation of phytochemical content and physical properties of broccoli, kale, and spinach. LWT, 155, 112892. Wang, W., Li, M., Emam Hassanien, R. H., Wang, Y., & Yang, L. (2018). Thermal performance of indirect forced convection solar dryer and kinetics analysis of mango. Applied Thermal Engineering, 134, 310-321. Waseed, M., Akhtar, S., Manzoor, M. F., Mirani, A. A., Ali, Z., Ismail, T., . . . Karrar, E. (2021). Nutritional characterization and food value addition properties of dehydrated spinach powder. Food Sci Nutr, 9, 1213-1221. Yamakage, K., Yamada, T., Takahashi, K., Takaki, K., Komuro, M., Sasaki, K., . . . Orikasa, T. (2021). Impact of pre-treatment with pulsed electric field on drying rate and changes in spinach quality during hot air drying. Innovative Food Science and Emerging Technologies, 68, 102615. Zhishen , J., Mengcheng, T., & Jianming, W. (1999). The determination of flavonoid contents in mulberry and their scavenging effects on superoxide radicals. Food Chemistry, 64, 555-559. Zhu, A., & Shen, X. (2014). The model and mass transfer characteristics of convection drying on peach slices. International Journal of Heat and Mass Transfer, 72, 345-351.

References

Guiné, R. P. (2018). The Drying of Foods and Its Effect on the. International Journal of Food Engineering Physical-Chemical, Sensorial and Nutritional Properties, 4(2), 93-100.
Álvarez - Parrilla, E., De la Rosa, L. A., Martínez, N. R., & González, G. A. (2007). Total phenols and antioxidant activity of commercial and wild mushrooms from chihuahua, Mexico fenoles totalesy capacidad antioxidante de hongos comercialesy silvestres De Chihuahua, México. CYTA-Journal of Food, 5(5), 329-334.
Amarowicz, R., & Pegg, R. B. (2008). Legumes as a source of natural antioxidants. European Journal of Lipid Science and Technology, 110(10), 865-878.
Aravindh, M. A., & Sreekumar, A. (2015). Solar drying—a sustainable way of food processing. In Energy sustainability through green energy (pp. 27-46). Sharma: Springer India.
Benzie, I. F., & Strain, J. J. (1996). The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant power”: The FRAP assay. Analytical Biochemistry, 239(1), 70-76.
Chew, Y. L., Lim, Y. Y., Omar, M., & Khoo, K. S. (2008). Antioxidant activity of three edible seaweeds from two areas in South East Asia. LWT-Food Science and Technology, 41(6), 1067-1072.
FAOSTAT. (2024, December 20 ). Food Agriculture Organization of the United Nations. Retrieved January 21, 2025, from https://www.fao.org/faostat/en/#data/QCL
Galla, N. R., Pamidighantam, P. R., Karakala, B., Gurusiddaiah, M. R., & Akula, S. (2017). Nutritional, textural and sensory qualitu of biscuits supplemented with spinach (Spinacia oleracea L.). International Journal of Gastronomy and Food Science, 7, 20-26.
García-Moreira, D. P., López-Vidaña, E. C., Moreno, I., & Delgadillo-Ruiz, L. (2025). Impact of Spectral Irradiance Control on Bioactive Compounds and Color Preservation in Solar Dried Papaya. Processes, 13, 2311.
García-Moreira, D. P., Moreno, I., Irigoyen-Campuzano, J., Martín-Domínguez, I., García-Valladares, O., & López-Vidaña, E. C. (2024). Effect of convective drying on color, water activity, and browning index of peach slices. Revista Mexicana de Ingeniería Química, 23(1).
Gutiérrez-Martínez, S., Hernández-Varela, J., Chanona-Pérez, J., Méndez-Méndez, J., González-Martínez, H., Perea-Flores, M., . . . González-Victoriano, L. (2024). Study of drying, thermal, shrinkage, and color kinetics using digital and thermographic imaging of potato slices under real-time convective drying. Revista Mexicana de Ingeniería Química, 23(3), Alim24322.
Kaur, A., Kaur, D., Oberoi, D., Gill, B., & Sogi, D. (2008). Effect of dehydration on physicochemical properties of mustard, mint and spinach. Journal of Food Processing and Preservation, 32, 103-116.
Krokida, M. K., Tsami, E., & Maroulis, Z. B. (1998). KINETICS ON COLOR CHANGES DURING DRYING OF SOME FRUITS AND VEGETABLES. Drying Technology: An International Journal, 3(5), 667-685.
Manzoor, M. F., Ahmed, Z., Ahmad, N., Aadil, R. M., Rahaman, A., Roobab, U., . . . Siddeeg, A. (2020). Novelprocessing techniques and spinach juice: Quality and safety im-provements. Journal of Food Science, 85(4), 1018-1026.
Mulokozi , G., & Svanber , U. (2003). Effect of Traditional Open Sun-Drying and Solar Cabinet Drying on Carotene Content and Vitamin A Activity of Green Leafy Vegetables. Plant Foods for Human Nutrition, 58(3), 1-15.
Nahar, N. M. (2009). Processing of vegetables in solar dryer in arid areas. International Solar Food Processing Conference. Indore, India.
Pal, A. A., & Acedo Jr, A. L. (2022). Quality profile of different vegetables dried using simple solardryers . Int. J. Postharvest Technology and Innovation, 8(4), 313-327.
S., G., Brat, P., Alter, P., & Amiot, J. (2005). Rapid determination of polyphenols and vitamin C in plant-derived products. Journal of Agricultural and Food Chemistry, 53, 1370-1373.
Spence , C. (2015). On the psychological impact of food colour. Flavour, 4(21). doi:https://doi.org/10.1186/s13411-015-0031-3
Vargas, L., Kapoor, R., Nemzer, B., & Feng, H. (2022). Application of different drying methods for evaluation of phytochemical content and physical properties of broccoli, kale, and spinach. LWT, 155, 112892.
Wang, W., Li, M., Emam Hassanien, R. H., Wang, Y., & Yang, L. (2018). Thermal performance of indirect forced convection solar dryer and kinetics analysis of mango. Applied Thermal Engineering, 134, 310-321.
Waseed, M., Akhtar, S., Manzoor, M. F., Mirani, A. A., Ali, Z., Ismail, T., . . . Karrar, E. (2021). Nutritional characterization and food value addition properties of dehydrated spinach powder. Food Sci Nutr, 9, 1213-1221.
Yamakage, K., Yamada, T., Takahashi, K., Takaki, K., Komuro, M., Sasaki, K., . . . Orikasa, T. (2021). Impact of pre-treatment with pulsed electric field on drying rate and changes in spinach quality during hot air drying. Innovative Food Science and Emerging Technologies, 68, 102615.
Zhishen , J., Mengcheng, T., & Jianming, W. (1999). The determination of flavonoid contents in mulberry and their scavenging effects on superoxide radicals. Food Chemistry, 64, 555-559.
Zhu, A., & Shen, X. (2014). The model and mass transfer characteristics of convection drying on peach slices. International Journal of Heat and Mass Transfer, 72, 345-351.