Effects of soaking on shelf life of soybean full fat flour

Abstract

Background: Soy products are gaining popularity as economical protein sources and nutritional or health foods.Processing that ensures improved shelf life is essential to enhance its use in alleviating malnutrition. Shelf life studies were carried out on Soybean full - fat flour samples produced from soybean soaked in different solutions. Methods: Soybean seeds were soaked, drained, steam bleached (100ºC) for 45 minutes, dehulled, dried in a cabinet drier and subsequently milled. The flour samples were stored and quality parameters (moisture content, ash content, protein content, crude fibre content, fat content, carbohydrate content and free fatty acid content) were determined at an interval of four weeks over a period of 12 weeks. Result: The crude fibre content of the chemically treated samples ranged from 5% to 12% over the 12 - week storage period. The moisture content of the control sample was 14% at the end of the storage period while that of the chemically treated samples were 12%, 6%, 8% for sodium carbonate, sodium bicarbonate and sodium chloride respectively. Soaking in 5% w/v sodium bicarbonate solution yielded a shelf stable soybean full fat flour. Sodium bicarbonate treated sample had the least free fatty acid content. Conclusion: Soaking sobean seeds in chemical solutions before processing reduced peroxidase action on the samples which was evident in the low free fatty acid content of the samples towards the end of the shelf life period.