Physical-Chemical Properties of Edible Film Made from Soybean Residue and Citric Acid

Wenjun Ma,Lianzhou Jiang,Yang Li,Sami Rokayya,Xiaonan Sui,Liang Xu

doi:10.1155/2018/4026831

Abstract

The effect of citric acid on the properties of soybean enzyme-assisted aqueous extraction processing (EAEP) residue edible film was studied. The washed soybean EAEP residue was produced by the process of EAEP. It was determined that the washed soybean EAEP residue is rich in fibers (76.10 ± 1.03%) and has lower oil and protein contents (7.74 ± 0.11% and 3.50 ± 0.20%, resp.). Edible films intended for food packaging have been produced from the washed EAEP residue combined with glycerol, different concentrations of citric acid (0%, 10%, 15%, 20%, 25%, and 30%), and sodium hypophosphite. The spectra have evidenced that the cross-linking reaction of citric acid and fibers has taken place in the residue. 30-CA films showed the highest tensile strength (17.52 MPa) and the lowest water vapor permeability (7.21 g·cm−1·s−1·Pa−1). Also, it indicated that citric acid can cross-link with the hydroxyls of polysaccharide and improve the compatibilization between the polymeric molecules to improve the intermolecular interaction between polysaccharide molecules, so that the water uptake is reduced. The smooth surface and better translucency of the films suggest that the EAEP residue films treated with citric acid are suitable for application in food packaging.

Highlights

IntroductionA large number of soybean residues which contain mostly crude fiber are generated in the process of extracting oil, protein, or other soy products from soybeans
Soybean is one of the most dominant oilseeds in the world
The result of elongation at break is exactly opposite to that of the tensile strength. e value of elongation at break was the highest in the 0-CA lm, which is 9.37%. e addition of citric acid increases the tensile strength and decreases the elongation at break, respectively. e lms with higher tensile strength were obtained when enzyme-assisted aqueous extraction processing (EAEP) residue lms were treated with higher concentration of citric acid

Summary

Introduction

A large number of soybean residues which contain mostly crude fiber are generated in the process of extracting oil, protein, or other soy products from soybeans. Due to the large amount of production and relatively low market values of soybean fiber besides its rich residues, it has a great potential as a raw material for preparing films. E surplus amount of residues is the limitation of EAEP as it produces 2.8 L of residues when extracting 1 L of oil [5]. E insoluble fiber produced by EAEP is a potential material for producing edible films due to the large amount of fiber content. Using the EAEP residue to prepare edible films could improve the values of coproduct of EAEP and reduce its limitation

Objectives

Results

Conclusion