Soybean meal has found limited applicability in plant based industrial adhesive and binder applications due to its inability to deliver the required mechanical strength. The focus of this project was to identify novel processing conditions to improve the overall functionality of the meal to achieve the required properties to meet the performance standards of large industrial applications such as wood composite adhesives. The use of soy in this context (i.e. plywood) has been demonstrated with soy flour and a proprietary cross-linker, but an opportunity to develop a more cost-effective ingredient system exists.
To guide research efforts to determine how the soymeal could be modified, the following insights were gathered:
KPI 1 – Determination of key structural and chemical differences between soymeal and soy flour: Other than particle size, our initial observations indicate minimal chemical and functional differences amongst the soymeal samples evaluated. When we compare the soymeal samples to soy flour and white flake, differences in surface hydrophobicity, water binding capacity and the protein dispersibility index were noted, while similarities in the secondary structure of the proteins were observed.
KPI 2 – Understand the key interactions between soy flour and cross-linker: Initial studies suggest soluble proteins in the soymeal and soy flour react with the PAE. We still need to understand what proteins (MW, etc.) are involved in the reaction. Higher viscosities were noted in the soymeal/PAE systems when compared to soy flour. It is currently believed that this viscosity difference is on account of non-protein components in the raw materials.
KPI 3 & KPI 4 – Characterize Wood Surface Interactions w/ Binder/Develop Novel Soymeal Binder Prototypes: Successful production of particle board using adhesive systems derived from soybean meal and extracted protein from soybean meal was achieved and preliminary testing completed. The dry bond and wet strength for soymeal adhesive systems were inferior to those of soy flour.
Proposed Next Steps:
? Further characterize the soluble protein fraction – composition and particle size distribution;
? Confirm the hypothesized interaction mechanisms between PAE and soluble soy protein and understand the role of the other components (i.e. sugar, fiber) in the interaction;
? Study the mechanism through which meal produces excessive viscosity in plywood adhesive formulations;
? Identify soymeal modifications to improve performance with a reasonable cost; and
? Exploration of other non-formaldehyde based cross-linkers.