High gravity enzymatic hydrolysis of non–gelatinized starch from black - purple rice

Huong Do Thi Thanh, Tien Thanh Nguyen
Author affiliations


  • Huong Do Thi Thanh School of Biotechnololgy and Food Technology, Hanoi University of Science and Technology, No. 1 Dai Co Viet, Hai Ba Trung, Ha Noi, Viet Nam
  • Tien Thanh Nguyen School of Biotechnololgy and Food Technology, Hanoi University of Science and Technology, No. 1 Dai Co Viet, Hai Ba Trung, Ha Noi, Viet Nam




Thanks to novel recombinant starch degrading enzymes which can directly hydrolyze raw starch at ambient temperature, the technology of hydrolysis of uncooked starch has recently been developed andproven to be effective. In combination with high substrate concentration (high gravity) approach, this technology not only saves the thermal energy for starch gelatinization but also reduces the impact of heat on valuable components in starch–containing raw materials. Black–purple rice is a specialty of Northwest Viet Nam, which contains high level of anthocyanin, a biologically active ingredient. In this study, commercial enzymes were applied to hydrolyze non–gelatinized black–purple rice to obtain anthocyanin–containing sugar solution. Factors affecting the starch conversion such as enzyme/substrate ratio, hydrolysis duration, temperature, and the presence of supporting enzymes in the hydrolysis process were investigated. The results showed that in the presence of Stargen 002, Viscozyme L, and Cellulast 1.5 L, more than 86 % of starch in a total of 320 g/L black-purple rice were converted into glucose after 72 hours at 50 °C. From black-purple rice, two products were received, including a glucose–rich hydrolysate (245.92 g/L) containing anthocyanin (30 mg/L) and a solid by–product rich in protein, which were very potential for food application.


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Yao S. L., Xu Y., Zhang Y. Y., and Lu Y. H. - Black rice and anthocyanins induce inhibition of cholesterol absorption in vitro, Food Funct. 4 (11) (2013) 1602-1608. doi:10.1039/ C3FO60196J.

Oikawa T., Maeda H., Oguchi T., Yamaguchi T., Tanabe N., Ebana K., Yano M., Ebitani T., and Izawa T. - The birth of a black rice gene and its local spread by introgression, Plant Cell 27 (9) (2015) 2401-2414. doi: 10.1105/tpc.15.00310.

Abdel–AalE.S. M., Young J. C., and Rabalski I. - Anthocyanin composition in black, blue, pink, purple, and red cereal grains, J. Agr. Food Chem. 54 (13) (2006) 4696-4704. doi:10.1021/jf0606609.

Sompong R., Siebenhandl–Ehn S. Linsberger–Martin G., and Berghofer E. - Physicochemical and antioxidative properties of red and black rice varieties from Thailand, China and Sri Lanka, Food Chem. 124 (1) (2011) 132-140. doi:https://doi.org/ 10.1016/j.foodchem.2010.05.115. https://doi.org/ 10.1016/j.foodchem.2010.05.115.">

Zhong Y., Xu J., Liu X., Ding L., Svensson B., Herburger K., Guo K., Pang C., and Blennow A. - Recent advances in enzyme biotechnology on modifying gelatinized and granular starch, Trends Food Sci. Tech. 123 (2022) 343-354. doi:https://doi.org/ 10.1016/j.tifs.2022.03.019. https://doi.org/ 10.1016/j.tifs.2022.03.019.">

Devantier R., Pedersen S. and Olsson L. - Characterization of very high gravity ethanol fermentation of corn mash, Effect of glucoamylase dosage, pre–saccharification and yeast strain, Appl. Microbiol. Biot. 68 (5) (2005) 622-629. doi: 10.1007/s00253–005–1902–9.

Pereira F. B., Guimarães P. M. R., Teixeira J. A., and Domingues L. - Optimization of low-cost medium for very high gravity ethanol fermentations by Saccharomyces cerevisiae using statistical experimental designs, Bioresource Technol. 101 (20) (2010) 7856-7863. doi: https://doi.org/10.1016/j.biortech.2010.04.082. https://doi.org/10.1016/j.biortech.2010.04.082.">

Cinelli B. A., Castilho L. R., Freire D. M. G., and Castro A. M. - A brief review on the emerging technology of ethanol production by cold hydrolysis of raw starch, Fuel 150(2015) 721-729. doi: https://doi.org/10.1016/j.fuel.2015.02.063. https://doi.org/10.1016/j.fuel.2015.02.063.">

Tien T. N., Nguyen T. C., Nguyen C. N., Nguyen T. T., Pham T. A., Pham N. H., and Chu–Ky S. - Protease increases ethanol yield and decreases fermentation time in no-cook process during very-high-gravity ethanol production from rice, Process Biochem. 117 (2022) 10-18. doi: https://doi.org/10.1016/j.procbio.2022.03.005. https://doi.org/10.1016/j.procbio.2022.03.005.">

Chu–Ky S., Pham T. H., Bui K. L. T., Nguyen T. T., Pham K. D., Nguyen H. D. T., Luong H. N., Tu V. P., Nguyen T. H., Ho P. H., and Le T. M. - Simultaneous liquefaction, saccharification and fermentation at very high gravity of rice at pilot scale for potable ethanol production and distillers dried grains composition, Food Bioprod. Process 98 (2016) 79-85. doi: https://doi.org/10.1016/j.fbp.2015.10.003. https://doi.org/10.1016/j.fbp.2015.10.003.">

Nguyen T. C., Chu–Ky S., Luong H. N. and Nguyen H. V. - Effect of pretreatment methods on enzymatic kinetics of ungelatinized cassava flour hydrolysis, Catalysts 10 (7) (2020). doi: 10.3390/catal10070760.

Kim M. S., Park J. T., Kim Y. W., Lee H. S., Nyawira R., Shin H. S., Park C. S., Yoo S. H., Kim Y. H., Moon T. W., and Park K. H. - Properties of a novel thermostable glucoamylase from the hyperthermophilic archaeon Sulfolobus solfataricus in relation to starch processing, Appl. Environ. Microb. 70 (7) (2004) 3933-3940. doi:10.1128/AEM. 70.7.3933–3940.2004.

Wang P., Singh V., Xue H., Johnston D. B., RauschK. D., and Tumbleson M. E. -Comparison of raw starch hydrolyzing enzyme with conventional liquefaction and saccharification enzymes in dry–grind corn processing, Cereal Chem. 84 (1) (2007) 10-14. doi:https://doi.org/10.1094/CCHEM–84–1–0010. https://doi.org/10.1094/CCHEM–84–1–0010.">

Prior R. L. and Wu X. - Anthocyanins: Structural characteristics that result in unique metabolic patterns and biological activities, Free Radical Res. 40 (10) (2006) 1014-1028. doi: 10.1080/10715760600758522.

Pham T. N., Lam T. D, Nguyen M. T, LeX. T., Vo D.V. N., Tran Q. T., Vo T. S. - Effect of various factors on extraction efficiency of total anthocyanins from Butterfly pea (Clitoria ternatea L. Flowers) in Southern Viet Nam, IOP Conference Series: Mater Sci. Eng. 544 (2019) p012013. doi: 10.1088/1757–899X/544/1/012013.

Rattanachomsri U., Tanapongpipat S., Eurwilaichitr L., and Champreda V. - Simultaneous non-thermal saccharification of cassava pulp by multi-enzyme activity and ethanol fermentation by Candida tropicalis, J. Biosci. Bioeng. 107 (5) (2009). doi:https://doi.org/ 10.1016/j.jbiosc.2008.12.024. https://doi.org/ 10.1016/j.jbiosc.2008.12.024.">




How to Cite

Huong Do Thi Thanh and T. Thanh Nguyen, “High gravity enzymatic hydrolysis of non–gelatinized starch from black - purple rice”, Vietnam J. Sci. Technol., vol. 61, no. 5, pp. 787–797, Aug. 2023.



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