Development and performance evaluation of small-scale low-viscous juice continuous pasteurizer

Document Type : Original research


Department of Agricultural & Biosystems Engineering, Makerere University P. O. Box 7062, Kampala, Uganda


Pasteurization is regarded as a critical unit operation in the juice processing chain because it extends the juice's shelf life. This study aimed to design, construct and assess the performance of the small-scale low-viscous juice continuous pasteurizer. The pasteurizer is equipped with three shell and tube heat exchangers (STHE) that operate on a counter-current flow system. During operation, raw juice is preheated in the regeneration section before being heated in the heating section to a specified pasteurization temperature. The juice is then held at pasteurization temperature in holding tubes for a specific period before being cooled in the regeneration and cooling section. The performance was evaluated by determining the maximum hot water temperature attainable, product pasteurization temperature and throughput at various pumping speeds of the product. With an initial heating time of 23 minutes, all product pump speeds over 792 rpm can yield a regeneration efficiency of about 50% with a throughput capacity of about 600 L/h. An automated control system can be used to adjust the pasteurizing temperatures. This enables effective use with a wide range of food products with pasteurization temperatures ranging from 72°C to 88°C under High-Temperature-Short-Time (HTST) processing. The logarithmic and quadratic polynomial models were found to be suitable for predicting throughput capacity and pasteurization temperature, respectively. The results from the validation showed R2 values of 97.52% and 99.28% for throughput capacity and pasteurization temperature, respectively. Juice pump speed did not affect the regeneration efficiency (p < 0.05). The pasteurizer is suitable for low-viscous food products.


Main Subjects

Adumene, S., Nwaoha, T. C., Ombor, G. P., & Abam, J. T. (2016). Design and off-design performance evaluation of heat exchanger in an offshore process configuration. Open Access Library Journal, 3, e2748.  doi:
Ahumuza, A., Nabututa, E., Kigozi, J., Zziwa, A., & Sempiira, E. (2017). Design, construction and performance evaluation of an automatic batch pasteurizer. Journal of Advances in Food Science & Technology, 4(4), 145-154.
Amit, S. K., Uddin, M. M., Rahman, R., Islam, S. M. R., & Khan, M. S. (2017). A review on mechanisms and commercial aspects of food preservation and processing. Agriculture & Food Security, 6(51), 1-22.  doi:
Ankwasa, P. (2018). Factors Affecting Pineapple Production In Ntungamo District. Makerere University, Retrieved from
Baidhe, E., Kigozi, J., & Balimunsi, H. K. (2022). Visualization of temperature and flow behavior in a continuous pasteurizer using computation fluid dynamics. Open Access Library Journal, 9, e8888.  doi:
Bennett, C. A., Kistler, R. S., Lestina, T. G., & King, D. C. (2007). Improving heat exchanger designs. Chemical Engineering Progress, 103(4), 40-45.
Bhatt, D., & Javhar, P. M. (2014). Shell and tube heat exchanger performance analysis. International Journal of Science and Research, 3(9), 1872-1881.
Bisig, W., Jordan, K., Smithers, G., Narvhus, J., Farhang, B., Heggum, C., Farrok, C., Saylor, A., Tong, P., Dornom, H., Bourdichon, F., & Robertson, R. (2019). The technology of pasteurisation and its effect on the microbiological and nutritional aspects of milk. Brussels, Belgium: International Dairy Federation.
Borah, A., & Hazarika, K. (2017). Simulation and validation of a suitable model for thin layer drying of ginger rhizomes in an induced draft dryer. International Journal of Green Energy, 14(13), 1150-1155.  doi:
Chaudhary, D. A., & Chaudhari, A. G. (2015). Performance evaluation of a plate type (HTST) milk pasteurizer. Research Journal of Animal Husbandry and Dairy Science, 6(2), 130-134.  doi:
Chavhan, S. D., Gohel, N. S., & Jha, R. S. (2016). Thermal-hydraulic performance of elliptic shape staggered tube cross flow heat exchanger at 45  angle of attack. International Journal of Current Engineering and Technology (Special Issue-5 (June 2016)), 75-77.
Deloitte. (2016). Uganda Economic Outlook 2016: The Story Behind the Numbers.  Retrieved from Outlook 2016 UG.pdf
Hall, S. (2012). Rules of thumb for chemical engineers (5th ed.): Butterworth-Heinemann.
Igboayaka, E. C., Ndukwu, M. C., & Ernest, I. C. (2019). A Modelling approach for determining the throughput capacity and energy consumption of a cassava tuber shredder. Journal of the Chinese Advanced Materials Society, 6(4), 801-816.  doi:
Kakac, S., Liu, H., & Pramuanjaroenkil, A. (2012). Heat Exchangers: Selection, rating, and thermal design (Third ed.): CRC Press Taylor & Francis Group.
Kanade, P., & Subramani, A. (2014). Hygienic design aspects of pasteuriser to assure effective pasteruisation of milk. Journal of Hygienic Engineering and Design, 8, 19-29.
Kern, D. Q. (1965). Process Heat Transfer (Internatioal Student ed.). Tokyo, Japan: McGraw-Hill International Book Company, Inc.
Kikulwe, E., Okurut, S., Ajambo, S., Nowakunda, K., Stoian, D., & Naziri, D. (2018). Postharvest losses and their determinants: A challenge to creating a sustainable cooking banana value chain in Uganda. Sustainability, 10(7), 2381.  doi:
Kiwana, D., & Naluwagga, A. (2016). SEEK: Fuel performance of faecal sludge briquettes in Kampala, Uganda. Retrieved from
Krishnan, N. M. C., & Kumar, S. B. (2016). An over view on shell and tube heat exchanger. International Journal of Engineering Science and Computing, 6(10), 2632-2636.
Kughur, P. G., Iornenge, G. M., & Ityonongu, B. E. (2015). Effects of postharvest losses on selected fruits and vegetables among small-scale farmers in gboko local government area of Benue state, Nigeria. International Journal of Innovation and Scientific Research, 19(1), 201-208.
Kumari, P., & Kumar, S. (2018). A study on post-harvest losses and constraints in banana cultivation in Vaishali district (Bihar). The Pharma Innovation Journal, 7(6), 93-95.
Kuteesa, A., Kisaame, E. K., Barungi, J., & Ggoobi, R. (2018). Public Expenditure Governance in Uganda’s Agricultural Extension System (ACODE Policy Research Paper Series, No. 84, 2018, Issue 84).  Retrieved from
Lebele-Alawa, B. T., & Ohia, I. O. (2014). Influence of fouling on heat exchanger effectiveness in a polyethylene plant. Energy and Power, 4(2), 29-34.  doi:
Malaikritsanachalee, P., Choosri, W., & Choosri, T. (2018). Study on kinetics of flow characteristics in hot air drying of pineapple. Food Science and Biotechnology, 27(4), 1047-1055.  doi:
Marwa, V. (2021). Design a VAT milk pasteurizer in Tanzania. Academic Journal of Engineering Studies, 1(4), AES.000525.
Ninshaba, P. (2015). Design and construction of a gas heated milk pasteuriser. Busitema University, Busitema, Uganda
Oyedokun, O. A., Achara, N., Muhammed, S. U., & Ishaq, O. O. (2017). Design and simulation of solar powered water pumping system for irrigation purpose in Kaduna, Nigeria. International Journal of Scientific Engineering and Technology, 6(10), 342-346.  doi:
Qian, X., Lee, S. W., & Yang, Y. (2021). Heat transfer coefficient estimation and performance evaluation of shell and tube heat exchanger using flue gas. Processes, 9(6), 1-19.  doi:
Rahiel, H. A., Zenebe, A. K., Leake, G. W., & Gebremedhin, B. W. (2018). Assessment of production potential and post-harvest losses of fruits and vegetables in northern region of Ethiopia. Agriculture & Food Security, 7(29).  doi:
Rosa, V. d. S., & Júnior, D. d. M. (2017). Design of heat transfer surfaces in agitated vessels. In S. M. S. Murshed & M. M. Lopes (Eds.), Heat Exchangers - Design, Experiment and Simulation (pp. 37-60): InterOpen. doi:10.5772/66729
Sarkar, S. (2015). Microbiological Considerations: Pasteurized Milk. International Journal of Dairy Science, 10(5), 206-218.  doi:
Shawabkeh, R. A. (2015). Steps for design of Heat Exchanger: Springer.
Uganda Investment Authority. (n.d.). The Compendium of Investment and Business Opportunities Volume 2 (Business Start-up Ideas). Uganda Investment Authority Retrieved from
Vengateson, U. (2010). Design of multiple shell and tube heat exchangers in series: E shell and F shell. Chemical Engineering Research and Design, 88, 725-736.  doi:
Wakholi, C., Cho, B.-K., Mo, C., & Kim, M. S. (2015). Current state of postharvest fruit and vegetable management in East Africa. Journal of Biosystems Engineering, 40(3), 238-249.  doi:
Widiatmo, J. S., & Hendrarsakti, J. (2018). Process Control of Milk Pasteurization using Geothermal Brine with Proportional Controller. Paper presented at the 43rd Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California.
Yousufuddin, S. (2018). Heat transfer enhancement of a shell and tube heat exchanger with different baffle spacing arrangements. Scholar Journal of Applied Sciences and Research, 1(6), 1-7.
Zhang, L., Shi, Z., & Yuan, T. (2020). Study on the coupled heat transfer model based on groundwater advection and axial heat conduction for the double u-tube vertical borehole heat exchanger. Sustainability, 12, 7345.  doi: