Published

2026-06-01

Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®)

Implementación de una nueva técnica de medición de índice de blancura como un indicador del blanqueamiento de cascarilla de Coffea arabica (variedad Castillo®)

DOI:

https://doi.org/10.15446/ing.investig.118094

Keywords:

Whiteness Index, digital photography, coffee parchment, hydrogen peroxide bleaching, physiochemical characterization (en)
índice de blancura, fotografía digital, cascarilla de café, blanqueamiento con peróxido de hidrógeno, caracterización fisicoquímica (es)

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Coffee parchment (CP) is a by-product of coffee bean processing that lacks significant value-added applications. However, CP has a high cellulose content, making it a promising source for this biopolymer extraction. This extraction process requires the removal of lignin and hemicellulose, with bleaching being a crucial step. The effectiveness of bleaching can be assessed using the whiteness index (WI), typically measured using robust colorimeters or reflectance spectrophotometers that require flat samples, which are not always readily available. This work presents a simple and promising technique for WI measurement using digital photography. The method was compared to standard colorimetry and demonstrated a strong linear correlation (R² = 0.996). To validate its usability, this novel technique was applied to optimize a well-known bleaching process, the alkaline hydrogen peroxide bleaching method, through response surface methodology. The optimal bleaching conditions were then subjected to experimental validation, and the bleached CP was characterized to confirm the accuracy of WI measurements obtained through digital photography. The Fourier-transform infrared (FTIR) and thermogravimetric analysis (TGA) findings indicate that the bleaching process resulted in the removal of hemicellulose and a partial removal of lignin. Scanning electron microscopy (SEM) images revealed that cellulose fibers remained adhered to the surface, likely due to incomplete lignin removal. X-Ray Diffraction (XRD) analysis revealed an enhancement in crystallinity from 59.7% in raw CP to 65.4% in bleached CP, suggesting the removal of amorphous phases such as hemicellulose and lignin. These results demonstrate the effectiveness of using digital photography for WI measurement in early cellulose isolation stages.

La cascarilla de café (CP) es un subproducto del procesamiento del grano de café que carece de aplicaciones con valor agregado. Sin embargo, la CP tiene un alto contenido de celulosa, lo que la convierte en una fuente prometedora para la extracción de este biopolímero. Este proceso de extracción requiere la eliminación de lignina y hemicelulosa, siendo el blanqueo un paso crucial. La efectividad del blanqueo puede evaluarse utilizando el Índice de Blancura (WI), que generalmente se mide con colorímetros robustos o espectrofotómetros de reflectancia y muestras planas, los cuales no siempre están disponibles. Este trabajo presenta una técnica sencilla y prometedora para medir el WI utilizando fotografía digital. El método se comparó con la colorimetría estándar y demostró una fuerte correlación lineal (R² = 0.996). Para validar su utilidad, esta nueva técnica se aplicó para optimizar un conocido proceso de blanqueo, el método de blanqueo con peróxido de hidrógeno alcalino, mediante metodología de superficie de respuesta. Las condiciones óptimas de blanqueo fueron validadas experimentalmente, y la CP blanqueada fue caracterizada para confirmar la precisión de las mediciones de WI obtenidas mediante fotografía digital. Los análisis de FTIR y TGA indicaron que el proceso de blanqueo eliminó la hemicelulosa y eliminó parcialmente la lignina. Las imágenes de SEM revelaron que las fibras de celulosa permanecieron adheridas, probablemente debido a una eliminación incompleta de lignina. El análisis XRD mostró un aumento en la cristalinidad del 59.7% en la CP cruda hasta el 65.4% en la CP blanqueada, lo que sugiere la eliminación de fases amorfas como hemicelulosa y lignina. Estos resultados demuestran la efectividad del uso de fotografía digital para la medición del WI en las etapas iniciales de la obtención de celulosa.

References

[1] R. C. Alves, F. Rodrigues, M. Antónia Nunes, A. F. Vinha, and M. B. P. P. Oliveira, “State of the art in coffee processing by-products,” in Handbook of Coffee Processing By-Products: Sustainable Applications, First., Elsevier Inc., 2017, ch. 1, pp. 1–26. https://doi.org/10.1016/B978-0-12-811290-8.00001-3

[2] A. Franca, L. Oliveira, and A. Franca, Coffee processing solid wastes: current uses and future perspectives, no. January 2009. 2009.

[3] A. L. Souza, F. S. Bernardino, R. Garcia, O. G. Pereira, F. C. Rocha, and A. J. V. Pires, “nutritivo de silagem de capim-elefante (Pennisetum pur-purem Schum.) com diferentes níveis de casca de café (Nutritive value of Pennisetum purpurem Schum. sillage with different levels of coffee husks),” Rev. Brasil. Zootec. no. 32, pp. 828–833, 2003. https://doi.org/10.1590/S1516-35982003000400007

[4] V. Benitez, M. Rebollo-Hernanz, S. Hernanz, S. Chantres, Y. Aguilera, and M. A. Martin-Cabrejas, “Coffee parchment as a new dietary fiber ingredient: Functional and physiological characterization,” Food Res. Int., vol. 122, no. March, pp. 105–113, 2019. https://doi.org/10.1016/j.foodres.2019.04.002

[5] M. Jeguirim, L. Limousy, and M. Labaki, Environmental applications of coffee processing by-products. Elsevier Inc., 2017. https://doi.org/10.1016/B978-0-12-811290-8.00009-8

[6] J. A. Suarez, P. A. Beaton, C. A. Luengo, and F. F. Felfli, “Coffee husk briquettes: A new renewable energy source,” Energy Sources, vol. 25, no. 10, pp. 961–967, 2003. https://doi.org/10.1080/00908310390232415

[7] E. B. Wondemagegnehu, N. K. Gupta, and E. Habtu, “Coffee parchment as potential biofuel for cement industries of Ethiopia,” Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, vol. 0, no. 0, pp. 1–12, 2019. https://doi.org/10.1080/15567036.2019.1656682

[8] S. R. Hughes et al., “Sustainable conversion of coffee and other crop wastes to biofuels and bioproducts using coupled biochemical and thermochemical processes in a multi-stage biorefinery concept,” Appl. Microbiol. Biotechnol., vol. 98, no. 20, pp. 8413–8431, 2014. https://doi.org/10.1007/s00253-014-5991-1

[9] S. A. Bekalo and H. W. Reinhardt, “Fibers of coffee husk and hulls for the production of particleboard,” Mater. Struct., vol. 43, no. 8, pp. 1049–1060, 2010. https://doi.org/10.1617/s11527-009-9565-0

[10] F. Campuzano, D. M. Escobar, and L. Ana María Torres, “Physicochem-ical characterization of coffee parchment of species Coffea arabica va-riety Castillo®,” Coffee Sci., vol. 19, Apr. 2024. https://doi.org/10.25186/.v19i.2182

[11] J. George and S. N. Sabapathi, “Cellulose nanocrystals: synthesis, func-tional properties, and applications.,” Nanotechnol. Sci. Appl., vol. 8, pp. 45–54, 2015. https://doi.org/10.2147/NSA.S64386

[12] H. P. S. Abdul Khalil, A. H. Bhat, A. Abu Bakar, P. Md. Tahir, I. S. M. Zaidul, and M. Jawaid, “Cellulosic Nanocomposites from Natural Fibers for Medical Applications: A Review,” in Handbook of Polymer Nanocom-posites. Processing, Performance and Application, Berlin, Heidelberg: Springer Berlin Heidelberg, 2015, pp. 475–511. https://doi.org/10.1007/978-3-642-45232-1_72

[13] I. Kouadri and H. Satha, “Extraction and characterization of cellulose and cellulose nanofibers from Citrullus colocynthis seeds,” Ind. Crops Prod., vol. 124, no. August, pp. 787–796, 2018. https://doi.org/10.1016/j.indcrop.2018.08.051

[14] B. Nasri-Nasrabadi, T. Behzad, and R. Bagheri, “Extraction and charac-terization of rice straw cellulose nanofibers by an optimized chemo-mechanical method,” J. Appl. Polym. Sci., vol. 131, no. 7, pp. 1–7, 2014. https://doi.org/10.1002/app.40063

[15] E. Csiszar, P. Kalic, A. Kobol, and E. D. P. Ferreira, “The effect of low frequency ultrasound on the production and properties of nanocrystal-line cellulose suspensions and films,” Ultrason. Sonochem., vol. 31, pp. 473–480, 2016. https://doi.org/10.1016/j.ultsonch.2016.01.028

[16] J. X. Liew et al., “Effect of hydrogen peroxide bleaching duration on Sesbania grandiflora pulp,” AIP Conf. Proc., vol. 2454, no. 1, Jun. 2022, https://doi.org/10.1063/5.0078265/2826159

[17] R. Ciriminna, L. Albanese, F. Meneguzzo, and M. Pagliaro, “Hydrogen Peroxide: A Key Chemical for Today’s Sustainable Development,” ChemSusChem, vol. 9, no. 24, pp. 3374–3381, Dec. 2016. https://doi.org/10.1002/cssc.201600895

[18] N. Mosier et al., “Features of promising technologies for pretreatment of lignocellulosic biomass,” Bioresour. Technol., vol. 96, no. 6, pp. 673–686, 2005. https://doi.org/10.1016/j.biortech.2004.06.025

[19] J. H. Chen, J. W. Xu, and C. X. Shing, “Decomposition rate of hydro-gen peroxide bleaching agents under various chemical and physical con-ditions,” J. Prosthet. Dent., vol. 69, no. 1, pp. 46–48, Jan. 1993. https://doi.org/10.1016/0022-3913(93)90239-K

[20] K. Liu, K. Yan, and G. Sun, “Mechanism of H2O2/bleach activators and related factors,” Cellulose, vol. 26, no. 4, pp. 2743–2757, 2019. https://doi.org/10.1007/s10570-019-02244-z

[21] W. S. Yeo and W. J. Lau, “Predicting the whiteness index of cotton fabric with a least squares model,” Cellulose, vol. 28, no. 13, pp. 8841–8854, 2021. https://doi.org/10.1007/s10570-021-04096-y

[22] A. N. M. A. Haque, S. A. Smriti, M. Hussain, N. Farzana, F. Siddiqa, and M. A. Islam, “Prediction of whiteness index of cotton using bleaching process variables by fuzzy inference system,” Fash. Text., vol. 5, no. 1, 2018. https://doi.org/10.1186/s40691-017-0118-9

[23] M. D. M. Pérez et al., “Development of a customized whiteness index for dentistry based on CIELAB color space,” Dent. Mater., vol. 32, no. 3, pp. 461–467, 2016. https://doi.org/10.1016/j.dental.2015.12.008

[24] R. W. Gerlach, X. Zhou, and S. F. Mcclanahan, “Comparative response of whitening strips to a low peroxide and potassium nitrate bleaching gel,” Am. J. Dent., vol. 15, no. SPEC. ISS. 1, pp. 19A-23A, Sep. 2002.

[25] T. Wang and Y. Zhao, “Optimization of bleaching process for cellulose extraction from apple and kale pomace and evaluation of their poten-tials as film forming materials,” Carbohydr. Polym., vol. 253, no. August 2020, p. 117225, 2021. https://doi.org/10.1016/j.carbpol.2020.117225

[26] Mathworks, “Image Processing Toolbok, User’s guide,” 2023.

[27] L. Segal, J. J. Creely, A. E. Martin, and C. M. Conrad, “An Empirical Method for Estimating the Degree of Crystallinity of Native Cellulose Using the X-Ray Diffractometer,” Text. Res. J., vol. 29, no. 10, pp. 786–794, 1959. https://doi.org/10.1177/004051755902901003

[28] C. M. G. C. Renard, Y. Rohou, C. Hubert, G. Della Valle, J. F. Thibault, and J. P. Savina, “Bleaching of apple pomace by hydrogen peroxide in alkaline conditions: Optimisation and characterisation of the products,” LWT–Food Sci. Technol., vol. 30, no. 4, pp. 398–405, 1997. https://doi.org/10.1006/fstl.1996.0195

[29] K. C. Coelho de Carvalho Benini, H. J. C. Voorwald, M. O. H. Cioffi, A. C. Milanese, and H. L. Ornaghi, “Characterization of a New Lignocel-lulosic Fiber from Brazil: Imperata brasiliensis (Brazilian Satintail) as an Alternative Source for Nanocellulose Extraction,” J. Nat. Fibers, vol. 14, no. 1, pp. 112–125, 2017. https://doi.org/10.1080/15440478.2016.1167647

[30] M. I. Najeeb et al., “Characterization of Lignocellulosic Biomass from Malaysian’s Yankee Pineapple AC6 Toward Composite Application,” J. Nat. Fibers, vol. 18, no. 12, pp. 2006–08, 2021. https://doi.org/10.1080/15440478.2019.1710655

[31] R. D. Kale, T. Getachew Alemayehu, and V. G. Gorade, “Extraction and Characterization of Lignocellulosic Fibers from Girardinia Bullosa (Steudel) Wedd. (Ethiopian Kusha Plant),” J. Nat. Fibers, vol. 17, no. 6, pp. 906–920, 2020. https://doi.org/10.1080/15440478.2018.1539940

[32] C. J. Lim, M. Arumugam, C. K. Lim, and G. C. L. Ee, “Mercerizing Ex-traction and Physicochemical Characterizations of Lignocellulosic Fiber from the Leaf Waste of Mikania micrantha Kunth ex H.B.K,” J. Nat. Fi-bers, vol. 17, no. 5, pp. 726–737, 2020. https://doi.org/10.1080/15440478.2018.1527742

[33] R. M. Silverstein, F. X. Webster, and D. J. Kiemle, Spectrometric Identifi-cation of Organic Compounds, Seventh. New York, NY: John Wiley & Sons, Inc., 2005. https://doi.org/10.1021/ed039p546

[34] M. Rizwan, S. R. Gilani, A. I. Durrani, and S. Naseem, “Cellulose extrac-tion of Alstonia scholaris: A comparative study on efficiency of differ-ent bleaching reagents for its isolation and characterization,” Int. J. Biol. Macromol., vol. 191, no. April, pp. 964–972, 2021. https://doi.org/10.1016/j.ijbiomac.2021.09.155

[35] B. Lindner, L. Petridis, P. Langan, and J. C. Smith, “Determination of cellulose crystallinity from powder diffraction diagrams,” Biopolymers, vol. 103, no. 2, pp. 67–73, 2015. https://doi.org/10.1002/bip.22555

[36] A. Thygesen, J. Oddershede, H. Lilholt, A. B. Thomsen, and K. Ståhl, “On the determination of crystallinity and cellulose content in plant fi-bres,” Cellulose, vol. 12, no. 6, pp. 563–576, 2005. https://doi.org/10.1007/s10570-005-9001-8

[37] A. Kaya, M. Hundley, A. Boydoh, and B. Hanson, “Characterization of tobacco stalk bleached pulp,” Cellul. Chem. Technol., vol. 52, no. 5–6, pp. 403–411, 2018.

[38] A. D. French and M. Santiago Cintrón, “Cellulose polymorphy, crystal-lite size, and the Segal Crystallinity Index,” Cellulose, vol. 20, no. 1, pp. 583–588, 2013. https://doi.org/10.1007/s10570-012-9833-y

[39] A. D. French, “Idealized powder diffraction patterns for cellulose polymorphs,” Cellulose, vol. 21, no. 2, pp. 885–896, 2014. https://doi.org/10.1007/s10570-013-0030-4

[40] L. Thompson, J. Azadmanjiri, M. Nikzad, I. Sbarski, J. Wang, and A. Yu, “Cellulose nanocrystals: Production, functionalization and advanced ap-plications,” Rev. Adv. Mater. Sci., vol. 58, no. 1, pp. 1–16, 2019. https://doi.org/10.1515/rams-2019-0001

[41] A. Hideno, “Thermogravimetric analysis-based characterization of suitable biomass for alkaline peroxide treatment to obtain cellulose and fermentable sugars,” BioResources, vol. 15, no. 3, pp. 6217–6229, 2020. https://doi.org/10.15376/biores.15.3.6217-6229

[42] P. Tomme, R. A. J. Warren, and N. R. Gilkes, “Cellulose Hydrolysis by Bacteria and Fungi,” Adv. Microb. Physiol., vol. 37, pp. 1–81, Jan. 1995. https://doi.org/10.1016/S0065-2911(08)60143-5

[43] J.-L. Wertz, O. Bédué, and J. P. Mercier, Cellulose science and technology, First. Lausanne, Switzerland: CRC/Taylor & Francis, 2010. https://doi.org/10.4324/9780203087701

How to Cite

APA

Campuzano Cardona, F. J., Escobar Sierra, D. M. & Torres López, A. M. (2026). Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®). Ingeniería e Investigación, 46(2), e118094. https://doi.org/10.15446/ing.investig.118094

ACM

[1]
Campuzano Cardona, F.J., Escobar Sierra, D.M. and Torres López, A.M. 2026. Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®). Ingeniería e Investigación. 46, 2 (Jun. 2026), e118094. DOI:https://doi.org/10.15446/ing.investig.118094.

ACS

(1)
Campuzano Cardona, F. J.; Escobar Sierra, D. M.; Torres López, A. M. Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®). Ing. Inv. 2026, 46, e118094.

ABNT

CAMPUZANO CARDONA, F. J.; ESCOBAR SIERRA, D. M.; TORRES LÓPEZ, A. M. Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®). Ingeniería e Investigación, [S. l.], v. 46, n. 2, p. e118094, 2026. DOI: 10.15446/ing.investig.118094. Disponível em: https://revistas.unal.edu.co/index.php/ingeinv/article/view/118094. Acesso em: 19 jul. 2026.

Chicago

Campuzano Cardona, Francisco José, Diana Marcela Escobar Sierra, and Ana María Torres López. 2026. “Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®)”. Ingeniería E Investigación 46 (2):e118094. https://doi.org/10.15446/ing.investig.118094.

Harvard

Campuzano Cardona, F. J., Escobar Sierra, D. M. and Torres López, A. M. (2026) “Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®)”, Ingeniería e Investigación, 46(2), p. e118094. doi: 10.15446/ing.investig.118094.

IEEE

[1]
F. J. Campuzano Cardona, D. M. Escobar Sierra, and A. M. Torres López, “Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®)”, Ing. Inv., vol. 46, no. 2, p. e118094, Jun. 2026.

MLA

Campuzano Cardona, F. J., D. M. Escobar Sierra, and A. M. Torres López. “Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®)”. Ingeniería e Investigación, vol. 46, no. 2, June 2026, p. e118094, doi:10.15446/ing.investig.118094.

Turabian

Campuzano Cardona, Francisco José, Diana Marcela Escobar Sierra, and Ana María Torres López. “Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®)”. Ingeniería e Investigación 46, no. 2 (June 1, 2026): e118094. Accessed July 19, 2026. https://revistas.unal.edu.co/index.php/ingeinv/article/view/118094.

Vancouver

1.
Campuzano Cardona FJ, Escobar Sierra DM, Torres López AM. Implementation of a new technique for whiteness index measurement as a performance indicator in the bleaching of Coffea arabica parchment (variety Castillo®). Ing. Inv. [Internet]. 2026 Jun. 1 [cited 2026 Jul. 19];46(2):e118094. Available from: https://revistas.unal.edu.co/index.php/ingeinv/article/view/118094

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