Shelf-stable Dried Okara from the Wet By-products of Philippine Soybean Curd Processing


Ma. Patricia V. Azanza1,2* and Fredelyn S. Gascon1

1Department of Food Science and Nutrition, College of Home Economics
University of the Philippines – Diliman, Quezon City, Philippines 1101
2Industrial Technology Development Institute, Department of Science and Technology
corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.


Okara is the wet by-product of silken soybean curd (taho) processing and other soybean processing procedures. It has a short shelf life of 12 h under Philippine ambient temperature (30 oC). Without further processing, it is generally used as feed or thrown as waste due to rapid spoilage. A two-stage drying scheme which utilized a manually-operated vertical screw-type press and mechanical dryer was applied to wet okara from a producer of silken tofu. The physicochemical, proximate, microbial, sensory, and rancidity parameters of dried okara were evaluated within its estimated shelf life. Drying of okara to about 5% moisture content extended its shelf life at 30 oC to almost 6 months when packed under vacuum in laminated PET/FOIL/PE (119 μm). End of shelf life was based on rancid odor through sensory evaluation. Shelf stable dried okara was described as yellowish cream, granular powder with slightly sweet, nutty, and moderately beany odor and taste. The proximate composition of freshly dried okara consisted of >20% protein, >10% fat, and>50% dietary fiber. The value added dried okara did not show any strong beany taste which normally limits the use of other dried soybean products as ingredient thus can be utilized as a functional ingredient in various food products. Dried okara can be incorporated into food products to increase the protein and dietary fiber content.



In the Philippines, amongst the significant industries utilizing soybeans include tofu (firm soybean curd or tokwa); taho (silken tofu/soft soybean curd sold as sweetened dish); and soymilk processing industries (O’Toole 1999, Bureau of Agricultural Statistics 2011). The difference between firm and silken tofu is primarily related to the water content of the formed soybean curd (Paino & Messinger 1991) with firm tofu containing lower amount of water. The production of firm tofu includes curd breaking and pressing which removes water from the curd (Chang 2006). In producing firm tofu, the coagulant is stirred quickly and vigorously into the hot soymilk then the curds are broken and pressed. Tofu texture becomes firmer and water content decreases as the pressure or weight applied becomes heavier during pressing (Liu 1997) . . . . . read more



AGUADO A. 2010. Development of okara powder as a gluten free alternative to all purpose flour for value added use in baked goods. [MS Thesis]. College Park, MD: University of Maryland. 80p. (Available at the University of Maryland Digital Repository).
ALENCAR E, FARONI L, PETERNELLI L, DA SILVA M, MOREIRA S. 2006. Soybean oil quality from grains stored under different conditions. In 9th International Working Conference on Stored Product Protection. p. 38-46
[APHA] American Public Health Association. 1992.Compendium of methods for the microbiological examination of foods, 3rd ed. Washington: American Public Health Association p. 225-228.
[AOAC] Association of Official Analytical Chemists. 2005. Official methods of analysis International, 18th ed. Gaithersburg, MD, USA: AOAC International. p.806-842.
[AOCS] American Oil Chemists’ Society.2009. Method Cd 19-90 2-Thiobarbituric acid value. Official methods and recommended practices of the American Oil Chemists’ Society. Champaign: American Oil Chemists’ Society. p.3.
BADARINATH V, RAGHAVENDRA P, HALAMI PM. 2010. Characterization of Lactic Acid Bacteria isolated from okara for probiotic properties. Int J Probiotics and Prebiotics 5(3):149-156.
[BAS] Bureau of Agricultural Statistics. 2011. Vegetables: Supply and Utilization Accounts by Year, Commodity and Item. Accessed from
BENJAKUL S, VISESSANGUAN W, PHONGKANPAI V, TANAKA M. 2005.  Antioxidative activity of caramelisation products and their preventive effect on lipid oxidation in fish. Food Chem90:231-239. doi:10.1016/j.foodchem.2004.03.045.
CALVERT G, LAWSON S, BILTON M.2013. Let them beat cake. Innov Pharm Technol Issue 44:42-45.
CHANG KC. 2006. Chemistry and technology of tofu making. In: Handbook of Food Science, Technology, and Engineering Vol. 4. Yiu H. ed. Boca Raton: CRC Press. p.171-1 to 171-4. Retrieved from,+technology+volume+4&hl=en&sa=X&ved=0ahUKEwjD4aLluJTLAhWJCI4KHY_-B20Q6AEIGzAA#v=onepage&q=handbook%20of%20food%20science%2C%20technology%20volume%204&f=false on 26 August 2015.
CHEN W, DUIZER L, CORREDIG M, DOUGLAS G. 2010.Addition of Soluble Soybean polysaccharides to dairy products as a source of dietary fiber. J Food Sci75(6):C478-C484.
CHOE E, MIN D. 2006. Mechanisms and Factors foe Edible Oils Oxidation. Comprehensive Reviews in Food Science and Food Safety 5: 169-186.
CORONEL E, TOBINAGA S. 2004. Drying the okara in a spouted bed. Drying 2004 – Proceedings of the 14th International Drying Symposium (IDS 2004); 2004 August 22-25; São Paulo, Brazil: State University Chemical Engineering School. C: 1767-1775.
CROWE T, WHITE P. 2001. Adaptation of the AOCS official method for measuring hydroperoxides from small-scale oil samples. J Am Oil Chem Soc 78(12):1267-1269.
[DTI] Philippine Department of Trade and Industry. 2008. Micro, small and medium enterprises. Accessed on 12 Feb 2014 from
DEBRUYNE I. 2004. Soybean Oil Processing: Quality Criteria and Flavor Reversion. Oil Mill Gazetteer 110 (July 2004): 10-11.
DOBARGANES MC, MARQUEZ-RUIZ G. 1998. Regulation of used frying fats and validity of quick tests for discarding the fats. Grasas y Aceites 49(3-4): 331-335
FREGA N, MOZZON M, AND LERCKER G.1999. Effects of free fatty acids on oxidative stability of vegetable oil. J Am Oil Chem Soc 76(3):325-329.
FU B, LABUZA T. 1997. Shelf Life Testing: procedures and prediction methods for frozen foods. In: Quality in Frozen Food. Erickson M& Hung Y ed. US: Springer, doi: 10.1007/978-1-4615-5975-7_19.
GRIZOTTO RK, RUFI CR, YAMADA EA, VICENTE E. 2010. Evaluation of the quality of a molded sweet biscuit enriched with okara flour. Food Sci Technol (Campinas) 30(Suppl. 1): 270-275. Retrieved on 12 Feb 2014 from
GRIZOTTO RK, AGUIRRE JM. 2011. Study of the flash drying of the residue from soymilk processing - "okara". Food Science and Technology (Campinas)31(3): 645-653. Retrieved from
GULLA S, WAGHRAY K. 2011.Effect of storage on physico-chemical characteristics and fatty acid composition of selected oil blends.  J Life Sci 3(1): 35-46.
HEAD KA. 1997. Isoflavones and other soy constituents in human health and disease. Alt Med 2(6): 433–450.
KACZMARCZYK M, MILLER M, FREUND G. 2012. The health benefits of dietary fiber: beyond the usual suspects of type 2 diabetes, cardiovascular disease and colon cancer. Metabolism 61(8) (August): 1058-1066. doi:10.1016/j.metabol.2012.01.017
KATAYAMA M, WILSON L. 2008.Utilization of okara, a byproduct from soymilk production, through the development of soy-based snack food. J Food Sci 73(3): S152-S157. doi: 10.1111/j.1750-3841.2008.00662.
KROKIDA MK, MAROULIS ZB, SARAVACOS GD. 2001.The effect of the method of drying on the colour of dehydrated products. Int J Food Sci Technol 36: 53–59.
LANGE J, WYSER Y. 2003.Recent innovations in barrier technologies for plastic packaging – a Review. Packag Technol Sci 16: 149-158. doi: 10.1002/pts.621.
LAROTONDA F, MATSUI K, PAES S, LAURINDO J. 2003. Impregnation of Kraft Paper with Cassava-Starch Acetate – Analysis of the Tensile Strength, Water Absorption and Water Vapor Permeability. Starch/Starke 55:504-510. doi:10.1002/star.200300179
LESCANO CA, ROCHA SC, FRAILE V. 2005. Drying of the soymilk residue “Okara” in spouted bed. In: ENPROMER – 2nd Mercosur Congress on Chemical Engineering and 4th Mercosur Congress on Process Systems Engineering; 2005 August 14 – 18; Village Rio Das Pedras, Club Med, Rio de Janeiro, Brazil: ENPROMER. p.1 – 10.
LI B, QIAO M, LU F. 2012. Composition, nutrition, and utilization of okara (soybean residue) Food Reviews International 28:231-252. doi: 10.1080/87559129.2011.595023.
LIGOT JS, PANGTS, SAYSON R, DE GUZMAN E, REBOTOS RL. 1994.The Utilization of Taho Production Residue as Flour and Meat Additive and Its Nutritive Analysis. Bato Balani 14(3):16-18.
LIU KS. 1997. Nonfermented oriental soyfoods. In: Soybeans: Chemistry, Technology, and Utilization. Singapore: Springer. p.142-155. Retrieved from on 27 August 2015.
MA CY, LIU WS, KWOK CF, AND KWOK F. 1997.Isolation and characterization of proteins from soymilk residue (okara). Food Res Int 29(8): 799-805.
MA G, JIN Y, PIAO J, KOK F, BONNEMA G, JACOBSEN E. 2005. Phytate, calcium, iron and zinc contents and their molar ratios in foods commonly consumed in China.J Agric Food Chem 53:10285-10290.
[MII] Megazyme International Ireland. 2011. Phytic Acid (Phytate)/Total Phosphorus: Measured as phosphorus released by phytase and alkaline phosphatase (Assay Procedure K-PHYT 07/11). Retrieved from on 26 April 2013.
MEILGAARD MC, CARR BT, AND CIVILLE GV. 2006.Descriptive Analysis Techniques. In: Sensory Evaluation Techniques, 4th ed. Florida: CRC Press, p. 173-181.
MEYER MD, TERRY LA. 2008.Development of a Rapid Method for the Sequential Extraction and Subsequent Quantification of Fatty Acids and Sugars from Avocado Mesocarp Tissue. J Agri Food Chem 56 (16): 7439-7445. doi: 10.1021/jf8011322
N’KOUKA K, KLEIN B, LEE S. 2004.Developing a lexicon for descriptive analysis of soymilks. J Food Sci (Sensory and Nutritive Qualities of Food) 69(7): S259-S263.
[OTA] Office of Technology Assessment (OTA). 1979. Application of Open Dating to Specific Foods. In: Open shelf-Life dating of food. Washington, D.C.: US Government Printing Office. p 59 – 76.
O’TOOLE DK. 1999.Characteristics and use of okara, the soybean residue from soy milk production – a review.J  Agric Food Chem 47(2): 363-371.
PAINO J, MESSINGER L. 1991. Tofu tips: A shopper’s guide to buying and storing. In: The Tofu Book: The New American Cuisine. USA: Avery. p 32-33. Retrieved from on 26 Aug 2015.
RAMONAITYTE DT, KERŠIENE M, ADAMS A, TEHRANI KA, DE KIMPE N. 2009.The interaction of metal ions with Maillard reaction products in a lactose–glycine model system. Food Res Int 42:331–336. doi:10.1016/j.foodres.2008.12.008
RINALDI VE, NG PK, BENNIK MR. 2000. Effects of dietary fibre and isoflavone contents of wheat extrudates enriched with okara. Cereal Chem 77 (2): 237-239.
RUKUNUDIN I, WHITE P, BERN C, BAILEY T. 1998.A modified method for determining free fatty acids from small soybean oil sample sizes. J Am Oil Chem Soc 75(5):563-568.
SALDAÑA MD, MARTINEZ-MONTEAGUDO SI. 2013. Oxidative stability of fats and oils measured by differential scanning calorimetry for food and industrial applications. In: Applications of Calorimetry in a Wide Context – Differential Scanning Calorimetry, Isothermal Titration Calorimetry and Microcalorimetry, Elkordy AA ed. InTech Open Access Publisher. p 445-468. doi: 10.5772/54486. Retrieved from on 21 May 2015
SENGUPTA S, CHAKRABORTY M, BHOWAL J, BHATTACHARYA DK. 2012.Study on the effects of drying process on the composition and quality of wet okara. Int J Sci Env 1(4): 319-330.
SODERGREN E. 2000. Lipid Peroxidation in vivo: Evaluation and application of methods for measurement. In: Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine. Sweden: Tryck & Medier. 949p.
SunOpta. 2007.Grains and Foods Group, Supreme Soy Okara. Minnesota, USA: SunOpta, Inc. Available from
TODA K, CHIBA K, ONO T. 2007. Effect of components extracted from okara on the physicochemical properties of soymilk and tofu texture. J Food Sci 72(2):c108-13
TORRES-PEÑARANDA AV, REITMEIER CA, WILSON LA, FEHR WR, NARVEL JM. 1998.Sensory characteristics of soymilk and tofu made from lipoxygenase-free and normal soybeans. J Food Sci 63(6):1084 -1087.
TURHAN S, TEMIZ H, SAGIR J. 2007.Utilization of wet okara in low-fat beef patties.J Muscle Foods18: 226–235. doi: 10.1111/j.1745-4573.2007.00081.
[USDA] United State Department of Agriculture, Agricultural Research Service. 2013. USDA National Nutrient Database for Standard Reference, Release 26. Retrieved from on 4 Feb 2014.
[USFDA] United States Food and Drug Administration. 2001. Bacteriological Analytical Manual. Retrieved from on 21 May 2015.
VAHCIC N, HRUSKAR M. 1999.Quality and sensory evaluation of used frying oil from restaurants. Food Technol Biotechnol 37(2): 107-112.
VELASCO J, DOBARGANES C, MÁRQUEZ-RUIZ G. 2003.Variables affecting lipid oxidation in dried microencapsulated oils. Grasas y Aceites 54(3): 304-314. doi: 10.3989/gya.2003.v54.i3.246.
VILLANUEVA M, YOKOYAMA W, HONG Y, BARTTLEY G, RUPEREZ P. 2011. Effect of high-fat diets supplemented with okara soybean by-product on lipid profiles of plasma, liver and faeces in Syrian hamsters. Food Chem 124:72-79. doi:10.1016/j.foodchem.2010.05.106.
WACHIRAPHANSAKUL S, DEVAHASTIN S. 2005.Drying kinetics and quality of soy residue (okara) dried in a jet spouted-bed dryer. Drying Technol 23 (6):1229–1242.
WAKIYAMA N, KUSAI A, NISHIMURA K. 1992. Mechanism of caking of granules containing oily materials. Int J Pharm (kidlington) 78(2-3): 95-102.
WATANABE T, KISHI A. 1984.Current ways of using and processing soybeans. In: The book of soybeans. Tokyo: Japan Publications Inc. p.31-38.
WICKRAMARATHNA GL, ARAMPATH PC. 2003.Utilization of okara in bread making Cey J Sci (Bio.Sci.) 31:29-33. Retrieved from on 12 Feb 2014.
YOSHIDA H, KONDO I, KAJIMOTO G. 1992. Participation of free fatty acids in the oxidation of purified soybean oil during microwave heating. J American Oil Chemists’ Society 69(11):1136-1140.
ZHOU J, ERDMAN J. 2009.Phytic acid in health and disease. Crit Rev Food Sci Nutr 35(6): 495-508.