Effect of different drying methods in the production of okara as food additives

Mohammad Sabri, Nur Hannan (2018) Effect of different drying methods in the production of okara as food additives. [Project Paper] (Submitted)

Text lp FK 2018 12.pdf Download (3MB)

Abstract

The by-product produced from processed soybean is soybean waste or soybean residue or known as okara in Japanese. The soybean waste is in the form of pulp where it contains the insoluble part of soybean after blending and filtering process. Okara is obtained from processed soybean. Firstly, soybean will be soaked in water and then blended to form slurry. The slurry is then filtered to separate soymilk and the residue. The residue obtained is known as okara. Okara is often regarded as waste despite of its high nutritional value especially protein because of its high moisture content. Since okara is high in moisture content, it deteriorates rapidly. Thus, okara drying is used as preservation method to increase the shelf life of okara. The objectives of this study are to evaluate the effect of freeze and oven drying methods towards the moisture, protein and fat contents of okara, to study the effect of freeze and oven drying on the physical characteristics of okara which are colour and density, and to study the effect of storage on moisture and protein content of dried okara powder. In this project, two drying methods are used which are oven drying and freeze drying. Okara dried at 60°C for 24 hours by using oven drying method and at -40°C for 72 hours by using freeze drying method. Drying rate that shows the drying behaviour of the okara also being analysed. Moisture, protein and fat content analysis are carried out on the wet and dried okara. Physical characteristic analysis which are colour and density also carried out on the okara. The results obtained from this study are the moisture content of wet, freeze and oven dried okara are 71.53%, 5.68% and 5.49% respectively, the results obtained for protein content of wet, freeze and oven dried okara are 34.77%, 34.21 % and 34.27% respectively, and the results obtained for fat content of wet, freeze and oven dried okara are 0.85%, 0.46% and 0.35% respectively. The colour analysis for both drying methods show that the both dried okara powder are light and yellow in colour, but oven dried okara is redder than freeze dried okara. The density of freeze and oven dried okara are 0.32 and 0.68 g/cm3 respectively. Finally, after two weeks, the moisture and protein contents of dried okara powder are analysed. The results obtained for moisture content of freeze and oven dried okara are 5.83% and 5.60% respectively, the results obtained for protein content of freeze and oven dried okara are 34.21 % and 34.26% respectively. The costing for freeze drying is higher than oven drying in term of operational and equipment costs. As a conclusion, both drying methods effectively dried the okara because they successfully reduce large amount of moisture in okara while retaining valuable nutrient content of okara which are protein. Both methods used remove high amount of moisture from the wet okara to a safe level for storage, and they also preserve the protein content of okara. Both drying methods also produce dried okara powder with light colour which is good to be used as food additives as it will not affect the colour of the food and the low density of okara powder which will be convenient for storage and transportation. However, in term of costing, the oven drying method will be better than freeze drying method as the operational and equipment costs for oven drying are way lower than that of freeze drying.

Item Type:	Project Paper
Faculty:	Faculty of Engineering
Depositing User:	Ms Siti Mariam Giman
Date Deposited:	27 Oct 2023 08:17
Last Modified:	27 Oct 2023 08:17
URI:	http://psaspb.upm.edu.my/id/eprint/1610

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