Evaluation and optimization of orange peeling machine performance based on physical-geometric characteristics of the fruit

Document Type : Research Paper

Authors

1 Professor, Agrotechnology Department of Agrotechnology, College of Abouraihan, University of Tehran, In Pakdasht, Tehran Province, I.R.Iran

2 Ahgrotechnology department , College of abouraihan, University of Tehran, Pakdasht,,IRAN

Abstract

Sour Orange peel (Citrus aurantium) contains bittering compounds such as naringenin and limonin, the presence of which in the juice reduces the sensory quality of the product. Accurate and effective peeling is a key step in the processing of oranges. In this study, the physical and geometric properties of orange fruit were investigated. The results showed that oranges have a shape close to a sphere with a sphericity of 0.96 which has a positive effect on the design of peeling equipment. To optimize the performance of the orange peeler, the rotational speed of the cylinder (5 levels: 300, 500, 700, 900 rpm), the feed rate (4 levels:1, 3, 6, and 8 oranges per turn) and the mesh size of the blade (3 levels: 2, 3 and 4 mm) were evaluated in a completely randomized factorial design with three replications. The response variable was the average percentage of peeled area. The results of the analysis of variance showed that the effect of rotational speed, feed rate and blade mesh size as well as their interaction were significant at the 1% probability level. By increasing the rotational speed to 900 rpm, the peeling percentage increased significantly, but at speeds higher than 900 rpm and 4 mm mesh, mechanical damage to the fruit and a decrease in quality were observed. The optimal operating conditions of the device were obtained, which included a rotational speed of 900 rpm, feeding of 6 oranges and a blade mesh of 3 mm.

Keywords

Main Subjects

Introduction

Sour orange peel contains important bittering compounds such as naringenin and limonin, which, if they penetrate into the fruit juice, create an aftertaste and significantly reduce the sensory quality of the product. Due to its relative solubility in water and high heat resistance, naringenin is separated from the pulp and enters the aqueous phase even during pasteurization and storage. Therefore, accurate and effective peeling before juicing is a key step in orange processing.

Materials and Methods

In this study, the physical-geometric properties of orange fruit were first investigated. The results showed that the average main diameters (a), (b) and (c) were 69.14 ,67.34and 65.15mm, respectively, the geometric mean diameter was 67.21 mm, the sphericity coefficient was 0.96, the volume was 3.18 cm3 and the surface area was 41.16 cm2. The nearly spherical shape of oranges (96% sphericity) makes it easier to design mechanical peeling equipment. With a cylindrical abrasive peeling machine designed and manufactured to optimize its performance, the effect of three parameters: rotational speed of the abrasive cylinder (300, 500, 700 and  900 rpm), feeding rate (1, 3, 6 and 8 fruits per turn) and mesh size of the abrasive blade (2, 3 and 4 mm) on the percentage of peeled surface was investigated in a completely randomized factorial design with three replications.

Results and Discussion

The results of the analysis of variance showed that the main effect of all three factors and their two-way and three-way interaction effects were significant at the 1% probability level. By increasing the rotational speed to 900 rpm, the percentage of peeling increased significantly (p<0.01). However, at speeds above 900 rpm, and especially at a mesh size of 4 mm, severe mechanical damage to the fruit and a decrease in visual quality were observed. The optimal operating conditions of the device were obtained through an interaction analysis, which included a rotational speed of 900 rpm, a feeding rate of 6 fruits, and a blade mesh size of 3 mm. Under these conditions, the average peeled percentage was more than 88% and mechanical damage was at the lowest level.

Conclusion

The effect of water spraying during peeling on reducing the bitterness of the final juice was investigated through sensory evaluation (by 10 trained evaluators). The results showed that continuous water spraying during the process significantly reduced the bitterness intensity of the juice (p<0.05), which is due to the rapid washing of naringin and limonin released from the fruit surface. Finally, the designed device, by applying optimal conditions and a water spraying system, is capable of peeling oranges with high efficiency, minimal mechanical damage, and maintaining the sensory quality of the juice, and provides a practical and economical solution for small and medium-sized orange processing industries.

Funding

Financial support for this research from the university. Tehran the Faculty of Agricultural Technology of Aburaihan has been done in the form of a research paper of the student thesis of the first author and also a research paper for other authors.

Authorship contribution

Conceptualization, Seyed Ahmad Mirsadeghi and Gholamreza Chegini.; methodology, Seyed Ahmad Mirsadeghi.; software, Seyed Ahmad Mirsadeghi; validation, Seyed Ahmad Mirsadeghi and Gholamreza Chegini.; formal analysis, Seyed Ahmad Mirsadeghi and Gholamreza Chegini investigation,  Gholamreza Chegini resources,; data curation, Seyed Ahmad Mirsadeghi writing-original draft preparation, Seyed Ahmad Mirsadeghi and Gholamreza Chegini ,writing-review and editing, Gholamreza Chegini; visualization, Gholamreza Chegini; supervision, Gholamreza Chegini; project administration, Gholamreza Chegini; funding acquisition, Gholamreza Chegini.

All authors have read and agreed to the published version of the manuscript.

Declaration of Generative AI and AI-assisted technologies in the writing process

Authors didn’t use of generative AI and AI-assisted technologies in the writing process of their manuscript in the core manuscript.

Data availability statement

The data that support the finding of this study will be available from the corresponding author

Acknowledgements

We would like to thank the University of Tehran, for financial support in carrying out this research.

Ethical considerations

The authors avoided data fabrication, falsification, plagiarism, and misconduct.

Conflict of interest

The authors declare no conflict of interest.

References

Bustamante, J. Van Stempvoort, S.  García-Gallarreta, M. J.A. Houghton, H.K. Briers, V.L. Budarin, A.S. Matharu, J.H. Clark, (2016). Microwave assisted hydro-distillation of essential oils from wet citrus peel waste. J. Clean. Prod. 137, 598–605.
Ferrer, V., Costantino, G., Paoli, M., Paymal, N., Quinton, C., Ollitrault, P., Tomi, F., Luro, F. (2021). Intercultivar Diversity of Sour Orange (Citrus aurantium L.) Based on Genetic Markers, Phenotypic Characteristics, Aromatic Compounds and Sensorial Analysis. Agronomy, 11, 1084. https://doi.org/10.3390/agronomy11061084.
Foxcroft (2009). United states Patent Office. P.N.: 20090211462.
Garcia, E. and Barrett, D. M. (2006). Peel ability and yield of processing tomatoes by steam or lye. Journal of Food Processing and Preservation, 30(1), 3–14.
Hasegawa S., Vandercook C. E. Choi G. Y., Herman Z., and Ou P. (1985). Limonoid debittering of citrus juice sera by immobilized cells of Corynebacterium fascians, J. Food Sci. 50: 330-332.
Heinzen et al. (1997). United states Patent Office. P.N. 5660104.
Kazemi, S. (2013). Differential and integral calculus. Thomas, George. Fatemi Publications. Tehran. 476 pp. (In Persian).
Kimball D. A. (1991). Citrus processing Quality control and Technology, Chapman & Hall, New York.
 
Kimball D. A. and Norman S. I. (1990). Changes in california Naver orange juice duning commercial debittering, J. Food Sci. 55(1): 273-274.
Kohli, D., Padam, Singh, C., Vishwambhar, D., Mudgal, S., Kumar, J., Brijesh, K. (2021). Advances in peeling techniques for fresh produce, Journal of Food Process Engineering. e13826, P 1-18.
Li, Xuan. (2020), Methods of Peeling Fruits and Vegetables from: Handbook of Food Preservation CRC Press.
Maksoud, S., Abdel-Massih, R.M., Rajha, H.N., Louka, N., Chemat, F., Barba, F.J., Debs, E. (2021). Citrus aurantium L. Active Constituents, Biological Effects and Extraction Methods. An Updated Review. Molecules, 26, 5832.
Mortazavi, S.A., Zia-ol-Haq, S. H. (2004). Technology of processing citrus by-products. Ferdowsi University of Mashhad Publications, 332 pp. (In Persian).
Norman S. I. (1990). A commercial citrus debittering system, Trans. Citrus Eng. Conf. 36: 1-31.
Rafiq, Sh, Kaul, R, Sofi, S.A., Bashir, N, Nazir, F, Gulzar ,A. (2016). Citrus peel as a source of functional ingredient: A review. Journal of the Saudi Society of Agricultural Sciences, (6), 1-8.
Rownaghi, M., & Niakousari, M. (2024). Sour orange (Citrus aurantium) seed, a rich source of protein isolate and hydrolysate – A thorough investigation. Heliyon, 10(12).
Shen, Y., Khir, R., Wood, D., (2020). Pear peeling using infrared radiation heating technology, Innovative Food Science and Emerging Technologies, https://doi.org/10.1016/j.ifset.2020.102474.
Talmadge J. (1998). The Blade Geometry FAQ. Bellies and Angle section p1 – 10.
Topuz A., Topakci M., Canakci M., Akinci I., and Ozdemir F. (2005). Physical and nutritional properties of four orange varieties. J. Food Eng. Res., 66, 519-523.
Zaki, S.A. (2008). Design, construction and evaluation of walnut shelling machine. Master's thesis in mechanical engineering of agricultural machinery. Aburaihan Campus, University of Tehran. (in Persian)
Iranian Journal of Biosystem Engineering
Volume 57, Issue 2
July 2026
Pages 23-40

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History

  • Receive Date: 14 December 2025
  • Revise Date: 18 April 2026
  • Accept Date: 20 May 2026

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