PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

There are several different forms of coconut kernel products, such as copra, desiccated coconut, coconut chips, strips, and flakes, each with its identity, industrial standard, and use in the food sector. In view of this, many studies concentrate on drying kinetics and the quality of the final dried product and extend from laboratory-scale research to industrial operations. This article discusses the application of various drying processes for various types of coconut kernel products, the pre-treatment involved prior to drying and some qualitative aspects associated with the final product. The use of mathematical modelling in various drying techniques was also examined and compared in this article. The effects of drying parameters such as air temperature, velocity, and pre-treatment on drying rate, time, colour quality, energy consumption, and yield are particularly interesting. Future suggestions and directions are emphasised and featured to fill the research gap in this product and sector.

• Abidin, M. H. Z., Sabudin, S., Zakaria, J. H., & Batcha, M. F. M. (2014). Thin layer modeling of grated coconut drying. Applied Mechanics and Materials, 660, 367-372. https://doi.org/10.4028/www.scientific.net/AMM.660.367

• Agarry, S. E., & Aworanti, O. A. (2012). Modelling the drying characteristics of osmosised coconut strips at constant air temperature. Journal of Food Processing & Technology, 3(4), Article 1000151. https://doi.org/10.4172/2157-7110.1000151

• Ahou, K., Emmanuel, A. N., Patrice, K., & Benjamin, Y. (2014). Modelling of rough rice solar drying under natural convection. European Scientific Journal, 10(3), 141-156.

• Arulandoo, X., Sritharan, K., & Subramaniam, M. (2017). The coconut palm. In B. Thomas, B. G. Murray & D. J. Murphy (Eds.) Encyclopedia of applied plant sciences (2nd ed.: pp. 426-430). Elsevier. https://doi.org/10.1016/B978-0-12-394807-6.00237-9

• Anuththara, J. G. M., Edirisinghe, E. A. V. U., Amarasinghe, B. M. W. P. K., & Jayatunga, G. K. (2019, July 03-05). Kinetics and mathematical modeling of drying of parboiled paddy in a packed bed dryer. [Paper presentation]. Moratuwa Engineering Research Conference (MERCon), Moratuwa, Sri Lanka. https://doi.org/10.1109/MERCon.2019.8818766

• Arun, S., Balaji, S. S., & Selvan, P. (2014). Experimental Studies on drying characteristics of coconuts in a solar tunnel greenhouse dryer coupled with biomass backup heater. International Journal of Innovative Technology and Exploring Engineering, 4(5), 56-60.

• Bal, L. M., Kar, A., Satya, S., & Naik, S. N. (2010). Drying kinetics and effective moisture diffusivity of bamboo shoot slices undergoing microwave drying. International Journal of Food Science and Technology, 45(11), 2321–2328. https://doi.org/10.1111/j.1365-2621.2010.02402.x

• Erkmen, O., & Bozoglu, T. F. (2016). Food preservation by reducing water activity. In Food microbiology: Principles into practice (pp. 44–58). Wiley. https://doi.org/10.1002/9781119237860.ch30

• Chantaro, P., Sribuathong, S., Charoen, R., & Chalermchaiwat, P. (2016). Pre-treatment conditions affect quality and sensory acceptability of dried osmotic dehydrated coconut. International Food Research Journal, 23(4), 1453-1458.

• Cruz, A. C., Guiné, R. P. F., & Gonçalves, J. C. (2015). Drying kinetics and product quality for convective drying of apples (cvs. golden delicious and granny smith). International Journal of Fruit Science, 15(1), 54-78. https://doi.org/10.1080/15538362.2014.931166

• Deepa, J., Rajkumar, P., & Arumuganathan, T. (2015). Quality analysis of copra dried at different drying air temperatures. International Journal of Agricultural Science and Research (IJASR), 5(4), 1-5.

• Deng, L. Z., Mujumdar, A. S., Zhang, Q., Yang, X. H., Wang, J., Zheng, Z. A., Gao, Z. J., & Xiao, H. W. (2019). Chemical and physical pretreatments of fruits and vegetables: Effects on drying characteristics and quality attributes - A comprehensive review. Critical Reviews in Food Science and Nutrition, 59(9), 1408-1432. https://doi.org/10.1080/10408398.2017.1409192

• Devi, M., & Ghatani, K. (2022). The use of coconut in rituals and food preparations in India: A review. Journal of Ethnic Foods, 9(1), 1-13. https://doi.org/10.1186/s42779-022-00150-7

• Dippon, K., & Villaruep, E. R. (1996, July 15-19). Copra dryers and copra drying technologies. [Paper presentation]. Proceedings of the XXXIII Cocotech Meeting, Kuala Lumpur Malaysia.

• Fayose, F., & Huan, Z. (2016). Heat pump drying of fruits and vegetables: Principles and potentials for Sub-Saharan Africa. International Journal of Food Science 2016, 9673029. https://doi.org/10.1155/2016/9673029

• Feng, H., Yin, Y., & Tang, J. (2012). Microwave Drying of food and agricultural materials: Basics and heat and mass transfer modeling. Food Engineering Reviews, 4(2), 89–106. https://doi.org/10.1007/s12393-012-9048-x

• Guarte, R. C., Mühlbauer, W., & Kellert, M. (1996). Drying characteristics of copra and quality of copra and coconut oil. Postharvest Biology and Technology, 9(3), 361–372. https://doi.org/10.1016/S0925-5214(96)00032-4

• Guida, V., Ferrari, G., Pataro, G., Chambery, A., Di Maro, A., & Parente, A. (2013). The effects of ohmic and conventional blanching on the nutritional, bioactive compounds and quality parameters of artichoke heads. LWT - Food Science and Technology, 53(2), 569-579. https://doi.org/10.1016/j.lwt.2013.04.006

• Guiné, R. (2018). The drying of foods and its effect on the physical-chemical, sensorial and nutritional properties. ETP International Journal of Food Engineering, 4(2), 93–100. https://doi.org/10.18178/ijfe.4.2.93-100

• Gupta, V., Vijayalakshmi, N. S., Ashwini, B., Anbarasu, K., Vijayalakshmi, G., Prakash, M., Indiramma, A. R., Rangarao, G. C. P., & Ramesh, B. S. (2010). Shelf life enhancement of coconut burfi - an Indian traditional sweet. Journal of Food Quality, 33(3), 329–349. https://doi.org/10.1111/j.1745-4557.2010.00312.x

• Hii, C. L., & Ogugo, J. F. (2014). Effect of pre-treatment on the drying kinetics and product quality of star fruit slices. Journal of Engineering Science and Technology, 9(1), 122–134.

• Inyang, U. E., Oboh, I. O., & Etuk, B. R. (2018). Kinetic models for drying techniques—Food materials. Advances in Chemical Engineering and Science, 8(2), 27–48. https://doi.org/10.4236/aces.2018.82003

• Jayasekhar, S., Chandran, K. P., Thamban, C., Jaganathan, D., & Muralidharan, K. (2017). Analyzing the trade competitiveness of Indian coconut sector in the liberalization regime. Journal of Plantation Crops, 44(3), 147. https://doi.org/10.19071/jpc.2016.v44.i3.3163

• Jongyingcharoen, J. S., Wuttigarn, P., & Assawarachan, R. (2019). Hot air drying of coconut residue: Shelf life, drying characteristics, and product quality. IOP Conference Series: Earth and Environmental Science, 301(1), Article 012033. https://doi.org/10.1088/1755-1315/301/1/012033

• Joshi, S., Kaushik, V., Gode, V., & Mhaskar, S. (2020). Coconut oil and immunity: What do we really know about it so far? The Journal of the Association of Physicians of India, 68(7), 67–72.

• Kalayanamitra, K., & Assawarachan, R. (2022). Modeling the drying of coconut residue in fluidized bed dryer. Journal of Culinary Science & Technology, 1-15. https://doi.org/10.1080/15428052.2022.2036662

• Kamalanathan, G., & Meyyappan, R. M. (2014). Osmotic drying out of coconut slices in salt solution: Optimization of process parameters using response surface methodology. International Journal of ChemTech Research, 7(6), 2773-2785.

• Khanali, M., Banisharif, A., & Rafiee, S. (2016). Modeling of moisture diffusivity, activation energy and energy consumption in fluidized bed drying of rough rice. Heat and Mass Transfer, 52, 2541-2549. https://doi.org/10.1007/s00231-016-1763-z

• Konan, B. R., Konan, J. L., Assa, R. R., Oule, M., & Amanai, G. (2009). The physicochemical characteristics of coconut (Cocos nucifera L.) kernels in germination. Seed Science and Technology, 3(1), 1–7.

• Krishna, S., & Mathew, G. (2018). Development of a solar copra dryer incorporated with evacuated tubes. International Journal of Current Microbiology and Applied Sciences, 7(6), 2457-2465. https://doi.org/10.20546/ijcmas.2018.706.292

• Kurniawan, H., Sukmawaty, S., Ansar, A., Yuniarto, K., Sabani, R., & Murad, M. (2021). Introduksi teknologi pengolahan kelapa menjadi coconut chips di UKM maju bersama Desa Kekait, Gunung Sari, Lombok Barat [Introduction of coconut processing technology of coconut chips in UKM with Kekait Village, Gunung Sari, Lombok Barat]. Jurnal Ilmiah Abdi Mas TPB Unram, 3(1), 8-14. https://doi.org/10.29303/amtpb.v3i1.55

• Lal, J. J., Sreeranjit Kumar, C. V., & Indira, M. (2003). Coconut palm. In L. Trugo & R. M. Finglas (Eds.), Encyclopedia of Food Sciences and Nutrition (2nd ed., pp.1464-1475). Academic Press. https://doi.org/10.1016/B0-12-227055-X/00263-7

• Lamidi, R. O., Jiang, L., Pathare, P. B., Wang, Y. D., & Roskilly, A. P. (2019). Recent advances in sustainable drying of agricultural produce: A review. Applied Energy, 233–234, 367–385. https://doi.org/10.1016/j.apenergy.2018.10.044

• Lee, D., So, J. D., Jung, H. M., Mo, C., & Lee, S. H. (2018). Investigation of drying kinetics and color characteristics of white radish strips under microwave drying. Journal of Biosystems Engineering, 43(3), 237–246.

• Liu, H., Liu, H., Liu, H., Zhang, X., Hong, Q., Chen, W., & Zeng, X. (2021). Microwave drying characteristics and drying quality analysis of corn in China. Processes, 9(9), 1511. https://doi.org/10.3390/pr9091511

• Madamba, P. S. (2003). Thin layer drying models for osmotically pre-dried young coconut. Drying Technology, 21(9), 1759-1780. https://doi.org/10.1081/DRT-120025507

• Madhiyanon, T., Phila, A., & Soponronnarit, S. (2009). Models of fluidized bed drying for thin-layer chopped coconut. Applied Thermal Engineering, 29(14-15), 2849-2854. https://doi.org/10.1016/j.applthermaleng.2009.02.003

• Manikantan, M. R. R., Arumuganathan, T., Arivalagan, M., Matthew, A. C., & Hebbar, K. B. (2015). Coconut chips: A healthy non-fried snack food. Indian Coconut Journal, 34-36.

• Marikkar, J. M. N., & Madurapperuma, W. S. (2012). Coconut. In M. Siddiq (Ed.) Tropical and subtropical fruits: Postharvest physiology, processing and packaging (pp. 159-177). Wiley. https://doi.org/10.1002/9781118324097.ch9

• Meisami-asl, E., Rafiee, S., Keyhani, A., & Tabatabaeefar, A. (2010). Drying of apple slices (var. Golab) and effect on moisture diffusivity and activation energy. Plant Omics, 3(3), 97-102.

• Mithra, A., Swamy, G. J., Rajendran, S. P., Chandrasekar, V., Shanmgam, S., & Hasker, E. (2013). Coconut- value added products coconut : An extensive review on value added products. Indian Food Industry Magazine, 32(6), 1–9.

• Mohanraj, M., & Chandrasekar, P. (2008a). Comparison of drying characteristics and quality of copra obtained in a forced convection solar drier and sun drying. Journal of Scientific and Industrial Research, 67(5), 381-385.

• Mohanraj, M., & Chandrasekar, P. (2008b). Drying of copra in a forced convection solar drier. Biosystems Engineering, 99(4), 604-607. https://doi.org/10.1016/j.biosystemseng.2007.12.004

• Mohanraj, M., Chandrasekar, P., & Sreenarayanan, V. V. (2008). Performance of a heat pump drier for copra drying. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 222(3), 283-287. https://doi.org/10.1243/09576509JPE548

• Moses, J. A. A., Paramasivan, K., Sinija, V. R. R., Alagusundaram, K., Brijesh kumar, T., Alugusundaram, K., & Kumar, B. (2013). Effect of microwave treatment on drying characteristics and quality parameters of thin layer drying of coconut Jeyan. Asian Journal of Food and Agro-Industry, 6(02), 72-85.

• Motevali, A., Chayjan, R. A., Salari, K., & Taghizadeh, A. (2016). Studying the effect of different drying bed on drying characteristic of mint leaves. Chemical Product and Process Modeling, 11(3), 231-239. https://doi.org/10.1515/cppm-2015-0045

• Mühlbauer, W., & Müller, J. (2020). Quality kinetics. In Drying atlas (pp.63-66). Woodhead Publishing. https://doi.org/10.1016/b978-0-12-818162-1.00007-9

• Nelsonekanem, E., Alonge, A., George, E., & Ossom, I. (2020). Optimization of mechanically expressed coconut (Cocos Nucifera L.) oil using response surface methodology. The International Journal of Engineering and Science, 9(6),1-9. https://doi.org/10.9790/1813-0906010109www.theijes.com

• Niamnuy, C., & Devahastin, S. (2005). Drying kinetics and quality of coconut dried in a fluidized bed dryer. Journal of Food Engineering, 66(2), 267-271. https://doi.org/10.1016/j.jfoodeng.2004.03.017

• Nor, N. F. A., Ya’akob, H., Idris, A., Ngadiran, S., Anuar, N. S., & Sarmidi, M. R. (2021). Evolutions in virgin coconut oil: Liquid to powder. Jurnal Teknologi, 83(3), 119–132. https://doi.org/10.11113/jurnalteknologi.v83.16265

• Pestaño, L. D. B. (2015, April 11-12). Mathematical modeling of the drying process. [Paper presentation]. Third International Conference on Advances in Applied Science and Environmental Engineering (ASEE), Kuala Lumpur, Malaysia. https://doi.org/10.15224/978-1-63248-055-2-80

• Pestaño, L. D. B., & Jose, W. I. (2016). Engineering an improved coconut processing system in the Philippines at the farm-level. Journal of Advanced Agricultural Technologies, 3(1), 58-62. https://doi.org/10.18178/joaat.3.1.58-62

• Prades, A., Salum, U. N., & Pioch, D. (2016). New era for the coconut sector. What prospects for research? Oilseeds & Fats, Crops and Lipids, 23(6), 4–7. https://doi.org/10.1051/ocl/2016048

• Pravitha, M., Manikantan, M. R., Ajesh Kumar, V., Shameena Beegum, P. P., & Pandiselvam, R. (2022). Comparison of drying behavior and product quality of coconut chips treated with different osmotic agents. Lwt, 162, 113432. https://doi.org/10.1016/j.lwt.2022.113432

• Prieto, W. H., Iguti, A. M., & Nitz, M. (2011). Drying evaluation of green coconut pulp for obtaining a snack-like product. Procedia Food Science, 1, 1618–1627. https://doi.org/10.1016/j.profoo.2011.09.239

• Ramaswamy, H. S., & Nsonzi, F. (2007). Convective-air drying kinetics of osmotically pre-treated blueberries. Drying Technology, 16(235), 743-759. https://doi.org/http://dx.doi.org/10.1080/07373939808917433

• Revaskar, V. A., Pisalkar, P. S., Pathare, P. B., & Sharma, G. P. (2014). Dehydration kinetics of onion slices in osmotic and air convective drying process. Research in Agricultural Engineering, 60(3), 92-99.

• Salehi, F. (2021). Recent applications of heat pump dryer for drying of fruit crops: A review. International Journal of Fruit Science, 21(1), 546–555. https://doi.org/10.1080/15538362.2021.1911746

• Samson, A. S. (1971). Heat treatment of coconut meats and coconut meal. Journal of the Science of Food and Agriculture, 22(6), 312–316. https://doi.org/10.1002/jsfa.2740220612

• Santosa, I., Sulistiawati, E., & Aktawan, A. (2019). Mathematical modeling of drying behavior of coconut grate in a modified screw mixed dryer. IOP Conference Series: Materials Science and Engineering, 674(1), 1–6. https://doi.org/10.1088/1757-899X/674/1/012009

• Sarkar, A., Ahmed, T., Alam, M., Rahman, S., & Pramanik, S. K. (2020). Influences of osmotic dehydration on drying behavior and product quality of coconut (Cocos nucifera). Asian Food Science Journal, 15(3), 21-30. https://doi.org/10.9734/afsj/2020/v15i330153

• Satter, M. A. (2001, December 26-28). Optimization of copra drying factors by taguchi method. [Paper presentation]. 4th International Conference on Mechanical Engineering, Dhaka, Bangladesh.

• Sharabiani, V. R., Kaveh, M., Abdi, R., Szymanek, M., & Tanaś, W. (2021). Estimation of moisture ratio for apple drying by convective and microwave methods using artificial neural network modeling. Scientific Reports, 11(1), 1-12. https://doi.org/10.1038/s41598-021-88270-z

• Simpson, R., Ramírez, C., Nuñez, H., Jaques, A., & Almonacid, S. (2017). Understanding the success of Page’s model and related empirical equations in fitting experimental data of diffusion phenomena in food matrices. Trends in Food Science and Technology, 62, 194-201. https://doi.org/10.1016/j.tifs.2017.01.003

• Sutar, P., & Prasad, S. (2008, February 1-3). Microwave drying technology-recent developments and R&D needs in India. [Paper presentation]. 42nd ISAE Annual Convention, Bhopal, India.

• Tepe, T. K., & Tepe, B. (2020). The comparison of drying and rehydration characteristics of intermittent-microwave and hot-air dried-apple slices. Heat and Mass Transfer, 56(11), 3047–3057. https://doi.org/10.1007/s00231-020-02907-9

• Thanaraj, T., Dharmasena, N. D. A., & Samarajeewa, U. (2007). Comparison of drying behaviour, quality and yield of copra processed in either a solar hybrid dryer on in an improved copra kiln. International Journal of Food Science and Technology, 42(2), 125-132. https://doi.org/10.1111/j.1365-2621.2006.01087.x

• Thiyagarajan, R., Srinivasan, P., Aneesh, T., & Mayilvakanan, S. (2020). Design and fabrication of semi automatic coconut copra electric dryer. International Journal of Innovative Technology and Exploring Engineering, 9(6), 637-641. https://doi.org/10.35940/ijitee.f3323.049620

• These, H. (2016). Spoilage of vegetables and fruits. In O. Erkmen & T. F. Bozoglu (Eds.) Food microbiology: Principles into practice (pp.337–363). Wiley https://doi.org/10.1002/9781119237860.ch20

• Thiyagarajan, R., Srinivasan, P., Aneesh, T., & Mayilvakanan, S. (2020). Design and fabrication of semi automatic coconut copra electric dryer. International Journal of Innovative Technology and Exploring Engineering, 9(6), 637–641. https://doi.org/10.35940/ijitee.f3323.049620

• Vera, F. H. C., Soriano, A. N., & Dugos, N. P. (2021). A Comprehensive review on the drying kinetics of common tubers. Applied Science and Engineering Progress, 14(2), 146-155. https://doi.org/10.14416/j.asep.2021.03.003

• Waisundara, V. Y., Perera, C. O., & Barlow, P. J. (2007). Effect of different pre-treatments of fresh coconut kernels on some of the quality attributes of the coconut milk extracted. Food Chemistry, 101(2), 771-777. https://doi.org/10.1016/j.foodchem.2006.02.032

• Wutthigarn, P., Hongwiangjan, J., & Sripinyowanich Jongyingcharoen, J. (2018). Modeling of hot air drying of coconut residue. MATEC Web of Conferences, 192, 1-4. https://doi.org/10.1051/matecconf/201819203061

• Yahya, S., Shahrir, A. M., Syariffudden, M. A. A. A., Shafie, A., Shukri, J. M., Zaimi, Z. A. A. M., & Redzuan, S. A. (2020). A study of drying parameters on drying time and colour quality of grated coconut using tumbling mechanism in convective dryer. Food Research, 4(Suppl. 6), 64-69. https://doi.org/10.26656/fr.2017.4(S6).023

• Yu, Y., Jin, T. Z., & Xiao, G. (2017). Effects of pulsed electric fields pretreatment and drying method on drying characteristics and nutritive quality of blueberries. Journal of Food Processing and Preservation, 41(6), Article e13303. https://doi.org/10.1111/jfpp.13303