183: Physical and Mechanical Properties of Chickpea Protein-Alginate Foams: Comparative Analysis of Freeze Drying and Convection Drying

Introduction

The widespread use of non-biodegradable polymers like polyethylene and polystyrene for packaging has raised environmental and health concerns. Biodegradable alternatives, including alginate-based foams, offer a sustainable solution due to their biocompatibility and mechanical adaptability. This study aimed to develop chickpea protein-alginate foams and evaluate their stability after freeze-drying and convective drying, focusing on their physical, textural, and microbiological properties for potential packaging applications.

Methods

Foams were prepared by combining 2.5% sodium alginate with chickpea cooking water (aquafaba) in varying ratios (1:1, 1:0.5, 1:5, and 1:0), with calcium chloride-sodium citrate as a cross-linking agent. The mixtures were whipped, pH-adjusted to 4.0, and allowed to gel. Drying was performed using freeze-drying (25°C, 0.0998 mmHg) and convective drying (60°C, 3.3 m/s air) during 24 h. Physical properties (density, water activity, and color), and tensile parameters (force, stress, and elasticity) were assessed using standard techniques. Data were statistically analyzed using ANOVA and Tukey’s test (95% confidence).

Results

Freeze-dried foams exhibited higher density (1209.82 kg/m³) and lower water activity (aw = 0.453) compared to convective-dried foams (250.76 kg/m³, aw = 0.479). Both foams showed yellow-green hues and microbiological stability (aw < 0.479). Freeze-dried foams demonstrated higher rigidity and flexibility, with a tensile force of 7.52 N and modulus of elasticity of 0.976 Pa, while convective-dried foams were more resistant to initial deformation with a modulus of elasticity of 294 Pa. Convective-dried foams had a significantly higher maximum stress (26,316.12 Pa vs. 2845.25 Pa) and lower fracture energy.

Significance

The results demonstrate the potential of chickpea protein-alginate foams as biodegradable materials for packaging. The rigidity and flexibility of freeze-dried foams make them suitable for solid products, such as fruits, while convective-dried foams' lower density suggests applications in lightweight packaging. Future research should explore storage stability and extended functionality to further validate these materials' commercial viability. This study contributes to the advancement of sustainable packaging solutions aligned with environmental preservation objectives.

Authors: Julio Emmanuel Gonzalez-Perez, Oscar Jimenez-Gonzalez, Lizbeth Rosas-Ordoñez