(152a) Characterization of Novel Soybean Hull-Based Binders for Aqua-Feed Pellets

Soybean is one of the most cultivated crops in the world generating about 18–20 million tons of soybean hull (SBH) per year in the world (with ~50% of it for US only). Current applications of SBH are mainly animal feed and dietary fiber, with the rest being landfilled or incinerated. With the goal of producing value-added products from SBH and reducing the environmental problems caused by landfilling or incineration of this under-utilized biomass, the Alabama Center for Paper and Bioresource Engineering (AC-PABE) has recently developed a novel compound feed binder using 100% soybean hull (SBH) in collaboration with USDA-ARS [1]. The novel binder has exhibited superior binding performance in laboratory scale evaluations as compared to the commercial feed binders: carboxymethyl cellulose, corn starch, and wheat gluten [1]. In addition, the novel binder's production requires only traditional, simple to apply, and scalable acid treatment with minimum effluent.

The objective of this study is to characterize the chemical and physical properties of the novel binders and understand the interactions among different components such as protein, pectin, hemicellulose and cellulose and their synergistic effects under different processing conditions, with a goal of identifying the optimal processing conditions.

Evaluation of the mass balance of the filtrate and retained solids from the acid treatment showed that a significant amount of non-fibrous components, i.e., pectin and protein, are solubilized during the treatments (Fig 1). Chemical composition and functional group analysis confirmed the dissolution of pectin and protein, contributing to the binding properties of the SBH binders (SBH-1, 2, 3) as opposed to the untreated SBH (Table 1). The carboxylic acid content for SBH-1 is twice the value for the untreated SBH. This value is even higher for SBH-2 and SBH-3, due to the separation from fibers and having more dissolved pectin and protein in them (about 18% compared to 10% in SBH-1). We are evaluating the structural changes of pectin, protein, SBH fibers, and their synergistic effects under different processing conditions.

[1] B. Aksoy, Z. Jiang, M. Aksoy, B. Beck, Animal feed binders derived from pectin-and protein-containing feedstock, US Patent App. 16/745,562 (2020).