Background and objectives: Pectin is a multifunctional polysaccharide widely used in the food, pharmaceutical, and packaging industries. Owing to its valuable functional properties, global demand for pectin exceeds 30,000 tons per year, with an annual market growth of approximately 4–5%. Lime peel (Citrus aurantifolia), particularly its inner white layer (albedo), is rich in pectin and represents an economical and sustainable raw material for pectin production. Utilizing this agro-industrial by-product not only provides added economic value but also contributes to reducing the environmental impacts associated with waste disposal. Conventional pectin extraction methods rely on mineral acids, which, despite ensuring high extraction yields, are associated with elevated production costs and environmental concerns. In contrast, organic acids such as citric acid function as green solvents, providing desirable yields while minimizing adverse environmental effects. Accordingly, the present study aimed to optimize acid extraction of pectin from lime peel to achieve maximum yield and desirable quality characteristics, including high purity and adjustable degree of methoxylation. Methodology: Lime albedo was separated from fresh fruit, washed, chopped, and dried at 50 °C to a constant weight, then ground and passed through a 20-mesh sieve. For acid extraction, 10 g of albedo powder was mixed with an aqueous citric acid solution at a fixed liquid-to-solid ratio of 30:1 (v/w) under three pH levels (1, 2, and 3). The resulting suspension was subjected to extraction at temperatures of 65, 80, and 95 °C and for extraction times of 30, 60, and 90 minutes. After centrifugation, pectin was precipitated using absolute ethanol, washed with 96% ethanol, dried at 40 °C, and subsequently powdered. A Box–Behnken experimental design was employed with three independent variables (temperature, time, and pH) at three levels, comprising 15 experimental runs. Extraction yield was calculated gravimetrically; galacturonic acid content (GalA) was determined by a colorimetric method using the m-hydroxydiphenyl reagent with absorbance measured at 520 nm; and degree of esterification (DE) was quantified via a two-step titration method (neutralization and saponification). Data were fitted to a second-order polynomial model using Design Expert version 13, and the optimal model was selected based on analysis of variance (ANOVA), coefficient of determination (R²), adjusted R², and lack-of-fit tests. Results: The pectin extraction yield was significantly influenced by the processing conditions and varied between 8.21% and 53.8%. The highest yield was obtained at 80 °C, 90 minutes, and pH 1, whereas the lowest yield occurred at pH 3 under lower temperature conditions. The degree of esterification (DE) also showed a clear dependency on extraction parameters; the highest DE value (61.11%) was achieved under milder conditions (80 °C, 30 minutes, pH 3), indicating the production of high-methoxyl pectin. In contrast, more severe extraction conditions—such as pH 1 combined with prolonged extraction time—led to a marked reduction in DE to approximately 9.13%, resulting in low-methoxyl pectin. Galacturonic acid content was similarly affected by extraction severity; the highest purity (87.83%) was observed at pH 3, 30 minutes, and 80 °C, while significantly lower purity values were recorded under highly acidic conditions. The regression models developed for yield, DE, and GalA exhibited excellent statistical performance, with coefficients of determination (R²) exceeding 0.98, confirming the high accuracy and predictive capability of the models in describing the extraction system. Conclusion: The findings of this study confirm the effectiveness of citric acid as a green and environmentally friendly solvent for extracting pectin from lime peel. Under optimized conditions, pectin with high yield, high purity, and an adjustable degree of esterification was successfully obtained. The application of response surface methodology enabled precise modeling of the extraction process, and the close agreement between predicted and experimental values demonstrated the strong validity and reliability of the developed model.Given its high purity and tunable methoxyl content, the extracted pectin is suitable for a wide range of applications in the food, pharmaceutical, and bio-based packaging industries. Utilizing lime peel - an abundant by-product of the lime juice industry - as a raw material not only provides a valuable source for pectin production but also contributes to sustainable development, agricultural waste management, and the reduction of environmental impacts. This approach offers an effective strategy for converting plant-based waste materials into value-added products within related industries. |
-Allian, M., Ramasaviny, B. & Emmambuk, M., 2020. Extraction, Characterisation, and Application of Pectin from Tropical and Sub-Tropical Fruits: A Review. Food Reviews International, https://doi.org/ 10.1080/87559129.2020.1733008.
-Canteri-Schemin, M.H., Fertonani, H.C., Waszczynskyj, N. & Wosiacki, G., 2005. Extraction of pectin from apple pomace, Brazilian Archives of Biology and Technology. 48 (2), 259–266, https://doi.org/10.1590/s1516-89132005000200013.
-Chalapud, M.C., Salgado-Cruz, Ma de., Baümler, E.R., Carelli, A.A., Morales-Sanchez, E., Calderon-Domínguez, G. & García-Hernandez, A.B., 2023. Study of the physical, chemical, and structural properties of low- and high-methoxyl pectin-based film matrices including Sunflower Waxes. Membranes, 13 (10), 846, https://doi.org/10.3390/ membranes13100846.
-Chen, J., Liu, W., Liu, C. M., Li, T., Liang, R. H. & Luo, S. J., 2015. Pectin modifications A review. Critical Reviews in Food Science and Nutrition, 55(12), 1684–1698. https://doi.org/10.1080/ 10408398.2012. 718722.
-Dubey, P., Tripathi, G., Mir, S. S. & Yousuf, O., 2023. Current scenario and global perspectives of citrus fruit waste as a valuable resource for the development of food packaging film. Trends in Food Science & Technology, 141, Article 104190. https://doi.org/ 10.1016/j.tifs.2023.104190.
-Durán-Aranguren, D.D., Ramírez, C.J., Díaz, L., Valderrama, M.A. & Sierra, R., 2022. Pectins – The New-Old Polysaccharides: Production of Pectin from Citrus Residues. Process Alternatives and Insights on Its Integration under the Biorefinery Concept, http://dx.doi.org/10.5772/intechopen. 100153.
-Ebrahim Zadeh, M. & Zadbakht, M., 2006. Extraction of Pectin and Comparison of Yield, Degree of Esterification and Percentage of Galacturonic Acid in the Skin of Some Citrus. Magazine of Mazandaran University of Medical Sciences, 16 (54),52–59.
-Eça, K.S., Machado, M.T., Hubinger, M.D. & Menegalli, F.C., 2015. Development of active films from pectin and fruit extracts: light protection, antioxidant capacity, and compounds stability. Journal Food Science, 80 (11). https://doi.org/ 10.1111/1750-3841.13074.
-Fissore, E.N., Ponce, N.M., Escalada Pla, M., Stortz, C.A., Rojas, A.M. & Gerschenson, L.N., 2010. Characterization of acid-extracted pectin-enriched products obtained from Red Beet ( beta vulgaris l. var. conditiva) and butternut ( cucurbita moschata duch ex poiret), Journal Agricultural Food Chemical, 58 (6), 3793–3800. https://doi.org/10. 1021/jf903844b.
-Gharibzahedi, S.M., Smith, B. & Guo, Y., 2019. Ultrasound-microwave assisted extraction of pectin from fig (ficus carica L.) skin: optimization, characterization and bioactivity, Carbohydrate Polymer, 222, 114992. https://doi.org/10.1016 /j.carbpol.2019.114992.
-Hossain, Md., Ara, R., Yasmin, F., Suchi, M. & Zzaman, W., 2024. Microwave and ultrasound assisted extraction techniques with citric acid of pectin from Pomelo ( Citrus maxima) peel. Measurement: Food, https://doi.org/10.1016/j. meafoo.2024.100135.
-Hosseini, S., Parastouei, K. & Khodaiyan, F., 2020. Simultaneous extraction optimization and characterization of pectin and phenolics from sour cherry pomace. International Journal Biological Macromolecules, 158, 911–921, https://doi.org/ 10.1016/j.ijbiomac.2020.04.241.
-Jesmin Akhter, J., Sarkar, Sh., Tajnuba Sharmin, T. & Chandra Mondal, Sh., 2024. Extraction of pectin from powdered citrus peels using various acids: An analysis contrasting orange with lime. Applied Food Research, 4,100614. https://doi.org/10.1016/j.afres. 2024.100614.
-Lasunon, P. & Sengkhamparn, N., 2022. Effect of ultrasound-assisted, microwave-assisted and ultrasound-microwave-assisted extraction on pectin extraction from industrial tomato waste, Molecules, 27 (4), 1157. https://doi.org/10.3390/molecules270 41157.
-Liu, L., Cao, J., Huang, J., Cai, Y. & Yao, J., 2010. Extraction of pectins with different degrees of esterification from Mulberry Branch bark. Bioresource Technological, 101 (9), 3268–3273. https://doi.org/10.1016/j.biortech.2009.12.062.
-Ma, S., Yu, S., Zheng, X., Wang, X., Bao, Q & Guo, X., 2013. Extraction, characterization and spontaneous emulsifying properties of pectin from Sugar Beet Pulp. Carbohydrate Polymer, 98 (1), 750–753. https://doi.org/10.1016/j.carbpol.2013.06.042.
-Mahmud, M.M., Belal, M., Ahmed, S. & Hoque, M.M., 2021. Zzaman, Microwave-assisted extraction and characterization of pectin from citrus fruit wastes for commercial application. Food Resource, 5 (5), 80–88. https://doi.org/10.26656/fr.2017. 5(5).592.
-Mamiru, D. & Gonfa, G., 2023. Extraction and characterization of pectin from watermelon rind
-Martau, G.A., Mihai, M. & Vodnar, D.C., 2019. The use of chitosan, alginate, and pectin in the biomedical and food sector—biocompatibility, bio adhesiveness and biodegradability. Polymers, 11 (11), 1837. https://doi.org/10.3390/polym11111837.
-Marwa Mahmoud, F.M. Abu-Salem, D.E. & Azab., 2022. A comparative study of pectin green extraction methods from Apple Waste: characterization and functional properties. SSRN Electron. Journal. https://doi.org/10.2139/ssrn. 4005101.
-Mellinas, C., Ramos, M., Jimenez, A. & Garrigos, M.C., 2020. Recent trends in the use of pectin from agro-waste residues as a natural-based biopolymer for food packaging applications. Materials, 13 (3), 673. https://doi.org/10.3390/ma13030673.
-Mosayebi, V. & Emam Djomeh, Z., 2017. Optimization of ultrasound assisted extraction of pectin from black mulberry ( Morus nigra.L) pomace. Iranian Food Science and Technology Research Journal, 13 (4), 594-610. https://doi.org/10.22067/ifstrj.v1395i0.504 66.
-Oliveira, T.T., Rosa, M.F., Cavalcante, F.L., Pereira, P.H., Moates, G.K., Wellner, N., Mazzetto, S.E., Waldron, K.W. & Azeredo, H.M.C., 2016. Optimization of pectin extraction from banana peels with citric acid by using response surface methodology. Food Chemical, 198, 113–118, https://doi.org/10.1016/j.foodchem.2015.08.080.
-Pei, Ch., Hsien, T, Sh., Hsuan, F, Sh., Hsuan, H, L., Chi, Ch. & Yi, M, L., 2024. Microwave- and Ultrasound-Assisted Extraction of Pectin Yield and Physicochemical Properties from Lemon Peel. Journal of Agriculture and Food Research, https://doi.org/10.1016/j.jafr.2024.101009.
-Pereira, P.H., Oliveira, T.´I. N., Waldron, W. & Azeredo. H.M.C., 2016. Pectin extraction from pomegranate peels with citric acid. International Journal Biological Macromolecule, 88, 373–379, https://doi.org/10.1016/j. ijbiomac.2016.03.074.
-Pinheiro, E.R., Silva, I.M.D.A., Gonzaga, L.V., Amante, E.R., Te´ofilo, R.F., Ferreira, M.M. C. & Amboni, R.D.M.C., 2008. Optimization of extraction of high-ester pectin from passion fruit peel (passiflora edulis flavicarpa) with citric acid by using response surface methodology. Bioresource Technology, 99 (13), 5561–5566. https://doi.org/10.1016/j.biortech.2007. 10.058.
-Wai, W.W., Alkarkhi, A.F.M. & Easa, A.M., 2010. Effect of extraction conditions on yield and degree of esterification of Durian Rind pectin: an experimental design. Food Bioproduction Process, 88 (2–3), 209–214. https://doi.org/10.1016/j.fbp.2010.01.010.
-Xu, F., Zhang, S., Waterhouse, G. I. N., Zhou, T., Du, Y., Sun-Waterhouse, D. & Wu, P., 2022. Yeast fermentation of apple and grape pomaces affects subsequent aqueous pectin extraction: Composition, structure, functional and antioxidant properties of pectins. Food Hydrocolloid, 133,107945. https://doi.org/10.1016/j.foodhyd.2022.107945.
-Yapo, B.M., Robert, C., Etienne, I., Wathelet, B. & Paquot, M., 2008. Effect of extraction conditions on the yield, purity and surface properties of sugar beet pulp pectin extracts. Food Chemical, 100 (4), 1356–1364. https://doi.org/10.1016/j.foodchem.2005.12. 012.
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