The Effect of Freeze Drying and Determination of Heat Transfer on Various Maturity Levels of Robusta Coffee Fruits

Tri Hariyadi, Mohamad Djali, Bambang Nurhadi, Santi Rosniawaty


The quality of coffee beans is influenced by the level of maturity, which can be determined based on the skin color of the coffee fruit and post-harvest processing. The study was conducted to determine the effect of freeze-drying on various variations in the level of maturity of water content, caffeine, and heat transfer value. The freeze-drying method was chosen because it can maintain the chemical content of the food. Robusta coffee was obtained from Karawang Regency, West Java, Indonesia. Coffee fruit is sorted by skin color using a colorimeter. Fresh beans are obtained by stripping the fruit skin and epidermis and washing mucus. Fresh bean is reduced in size until it passes the 18-mesh sieve. Freeze-drying is operated at an initial temperature of -20 ℃, sublimation temperature of 40 ℃, and operating pressure of 1 to 6 mbar abs. Water content analysis using gravimetric methods, caffeine content analysis using UV-Vis spectrophotometry method, and fat content using the Soxhlet method. The total heat transfer value is determined from the cup to the material. The results showed that the freeze-drying process at semi-ripe to over-ripe maturity levels could reduce the water content to the permissible limit but cannot be used for unripe. The results of the statistical significance test show that the freeze-drying process at various maturity levels can significantly reduce the water content but can maintain the caffeine content in robusta coffee beans. The highest heat transfer value occurs at the un-ripe maturity level of 86.50 kJoule.


Caffeine; freeze-drying; heat transfer; maturity level; robusta coffee.

Full Text:



F. Y. F. Verhage, N. P. R. Anten, and P. C. Sentelhas, “Carbon dioxide fertilization offsets negative impacts of climate change on Arabica coffee yield in Brazil,†Clim. Change, vol. 144, no. 4, pp. 671–685, 2017, doi: 10.1007/s10584-017-2068-z.

E. Rahn, P. Vaast, P. Läderach, P. van Asten, L. Jassogne, and J. Ghazoul, “Exploring adaptation strategies of coffee production to climate change using a process-based model,†Ecol. Modell., vol. 371, no. January, pp. 76–89, 2018, doi: 10.1016/j.ecolmodel.2018.01.009.

R. J. Henry, “Innovations in plant genetics adapting agriculture to climate change,†Curr. Opin. Plant Biol., vol. 56, pp. 168–173, 2020, doi: 10.1016/j.pbi.2019.11.004.

A. P. Davis, H. Chadburn, J. Moat, R. O’Sullivan, S. Hargreaves, and E. N. Lughadha, “High extinction risk for wild coffee species and implications for coffee sector sustainability,†Sci. Adv., vol. 5, no. 1, pp. 1–10, 2019, doi: 10.1126/sciadv.aav3473.

S. Krishnan, Sustainable Coffee Production, no. September. 2017.

D. Komes and A. Bušić, “Antioxidants in Coffee,†in Processing and Impact on Antioxidants in Beverages, Elsevier Inc., 2014, pp. 25–32.

B. Cheng, H. E. Smyth, A. Furtado, and R. J. Henry, “Slower development of lower canopy beans produces better coffee,†J. Exp. Bot., vol. 71, no. 14, pp. 4201–4214, 2020, doi: 10.1093/jxb/eraa151.

W. B. Sunarharum, R. Ahmad, and E. Primadiani, “Effect of different manual brewing techniques to the sensory profile of the Indonesian Arabica and Robusta ‘natural coffees,’†IOP Conf. Ser. Earth Environ. Sci., vol. 475, no. 1, 2020, doi: 10.1088/1755-1315/475/1/012020.

N. Happyana, Y. M. Syah, and E. H. Hakim, “Discrimination of Metabolite Profiles of Gayo Roasted Arabica and Robusta Coffees,†Molekul, vol. 17, no. 1, pp. 98–106, 2022.

B. Kaido, N. Takashino, and K. Fuyuki, “Challenges of Arabica coffee marketing: A case study in Kerinci regency, Indonesia,†Asian J. Agric. Rural Dev., vol. 11, no. 1, pp. 53–62, 2021, doi: 10.18488/journal.ajard.2021.111.53.62.

W. Dong, R. Hu, Z. Chu, J. Zhao, and L. Tan, “Effect of different drying techniques on bioactive components, fatty acid composition, and volatile profile of robusta coffee beans,†Food Chem., vol. 234, pp. 121–130, 2017, doi: 10.1016/j.foodchem.2017.04.156.

J. C. Ramalho, I. P. Pais, A. E. Leitão, M. Guerra, F. H. Reboredo, C. M. Máguas, M. L. Carvalho, P. Scotti-Campos, A. I Ribeiro-Barros, F. J. C. Lidon, and F. M. DaMatta, “Can elevated air [CO2] conditions mitigate the predicted warming impact on the quality of coffee bean?,†Front. Plant Sci., vol. 9, no. March, pp. 1–14, 2018, doi: 10.3389/fpls.2018.00287.

V. M. C. Martínez, I. D. T. Aristizábal, and E. L. C. Moreno, “Evaluation of the composition effect of harvested coffee in the organoleptic properties of coffee drink,†Vitae, vol. 24, no. 1, pp. 47–58, 2017, doi: 10.17533/udea.vitae.v24n1a06.

L. Li, M. Zhang, X. Song, W. Wang, and B. Bhandari, “Changes in unfrozen water content and dielectric properties during pulse vacuum osmotic dehydration to improve microwave freeze-drying characteristics of Chinese yam,†J. Sci. Food Agric., vol. 99, no. 14, pp. 6572–6581, 2019, doi: 10.1002/jsfa.9938.

N. L. E. Wahyuni, R. Rispiandi, and T. Hariyadi, “Effect of bean maturity and roasting temperature on chemical content of robusta coffee,†IOP Conf. Ser. Mater. Sci. Eng., vol. 830, no. 2, 2020, doi: 10.1088/1757-899X/830/2/022019.

W. Dong, R. Hu, Y. Long, H. Li, Y. Zhang, K. Zhu, and Z. Chu, “Comparative evaluation of the volatile profiles and taste properties of roasted coffee beans as affected by drying method and detected by electronic nose, electronic tongue, and HS-SPME-GC-MS,†2018, doi: 10.1016/j.foodchem.2018.08.068.

F. Elmas, E. Varhan, and M. Koç, “Drying characteristics of jujube (Zizyphus jujuba) slices in a hot air dryer and physicochemical properties of jujube powder,†J. Food Meas. Charact., vol. 13, no. 1, pp. 70–86, 2019, doi: 10.1007/s11694-018-9920-3.

G. Adams, “The principles of freeze-drying.,†Methods Mol. Biol., vol. 368, no. 2, pp. 15–38, 2007, doi: 10.1007/978-1-59745-362-2_2.

R. Owusu-Apenten, Introduction to food chemistry. 2021.

S. Bhatta, T. S. Janezic, and C. Ratti, “Freeze-Drying of Plant-Based Foods,†Foods, vol. 9, pp. 1–22, 2020, doi: 10.3390/foods9010087.

K. Cheng, W. Dong , Y. Long, J. Zhao, R. Hu, Y. Zhang, and K. Zhu, “Evaluation of the impact of different drying methods on the phenolic compounds, antioxidant activity, and in vitro digestion of green coffee beans,†Food Sci. Nutr., vol. 7, no. 3, pp. 1084–1095, 2019, doi: 10.1002/fsn3.948.

S. Bhatta, T. Stevanovic, and C. Ratti, “Freeze-drying of maple syrup: Efficient protocol formulation and evaluation of powder physicochemical properties,†Dry. Technol., vol. 38, no. 9, pp. 1138–1150, 2020, doi: 10.1080/07373937.2019.1616751.

H. Yang, T. Sombatngamwilai, W. Y. Yu, and M. I. Kuo, “Drying Applications during Value-Added Sustainable Processing for Selected Mass-Produced Food Coproducts,†Processes, vol. 8, no. 3, 2020, doi: 10.3390/pr8030307.

V. K. Maurya, K. M. Gothandam, R. Vijay, S. Amita, and S. Pareek, “Effect of drying methods (microwave-vacuum, freeze, hot air and sun drying) on physical, chemical and nutritional attributes of five pepper (Capsicum annuum var. annuum) cultivars,†J. Sci. Food Agric., vol. 98, no. 9, pp. 3492–3500, 2018, doi: 10.1002/jsfa.8868.

M. Harguindeguy and D. Fissore, “On the effects of freeze-drying processes on the nutritional properties of foodstuff: A review,†Dry. Technol., vol. 38, no. 7, pp. 846–868, 2020, doi: 10.1080/07373937.2019.1599905.

V. Wahl, J. Khinast, and A. Paudel, Lyophilized protein powders: A review of analytical tools for root cause analysis of lot-to-lot variability, vol. 82. Elsevier B.V., 2016.

G. Hu, X. Peng, X. Wang, X. Li, X. Li, and M. Qiu, “Excavation of coffee maturity markers and further research on their changes in coffee cherries of different maturity,†Food Res. Int., vol. 132, no. February, 2020, doi: 10.1016/j.foodres.2020.109121.

S. Velásquez, A. P. Franco, N. Peña, J. C. Bohórquez, and N. Gutiérrez, “Classification of the maturity stage of coffee cherries using comparative feature and machine learning,†Coffee Sci., vol. 16, no. Equation 1, p. 1, 2021, doi: 10.25186/.v16i.1710.

M. Worku, B. de Meulenaer, L. Duchateau, and P. Boeckx, “Effect of altitude on biochemical composition and quality of green arabica coffee beans can be affected by shade and postharvest processing method,†Food Res. Int., vol. 105, 2018, doi: 10.1016/j.foodres.2017.11.016.

B. K. Choi, S. B. Park, D. R. Lee, H. J. Lee, Y. Y. Jin, S. H. Yang, and J. W. Suh, “Green coffee bean extract improves obesity by decreasing body fat in high-fat diet-induced obese mice,†Asian Pac. J. Trop. Med., vol. 9, no. 7, pp. 635–643, 2016, doi: 10.1016/j.apjtm.2016.05.017.

G. C. Román, R. E. Jackson, R. Gadhia, A. N. Román, and J. Reis, “Mediterranean diet: The role of long-chain ω-3 fatty acids in fish; polyphenols in fruits, vegetables, cereals, coffee, tea, cacao and wine; probiotics and vitamins in prevention of stroke, age-related cognitive decline, and Alzheimer disease,†Rev. Neurol. (Paris)., vol. 175, no. 10, pp. 724–741, 2019, doi: 10.1016/j.neurol.2019.08.005.

L. J. M. Alferink, J. C. Kiefte-De Jong, and S. D. Murad, “Potential Mechanisms Underlying the Role of Coffee in Liver Health,†Semin. Liver Dis., vol. 38, no. 3, pp. 193–214, 2018, doi: 10.1055/s-0038-1666869.



  • There are currently no refbacks.

Published by INSIGHT - Indonesian Society for Knowledge and Human Development