The effect of agar from the seaweed Gracilaria fisheri on properties of biodegradable starch foam

Abstract

This work focuses on the potential of agar from the seaweed Gracilaria fisheri to modify the properties of starch foam. The effects of different ratios of glycerol and agar on the properties of starch foams were investigated. All formulations used in this study produced easy-to-handle, smooth, single-use foam trays with no visible cracks. The addition of agar slightly affected the off-white color of the foam but red and yellow color values significantly decreased with increments of agar content. As the agar content was increased, the foam became less dense. A foam produced at a glycerol:agar ratio of 3:7 exhibited the highest values of flexural stress at maximum load (3.23 MPa), modulus (194.46 MPa) and hardness (97.50), and the highest temperature at maximum weight loss (Tmax) (337 °C). Therefore, starch foam modified with agar from Gracilaria fisheri showed suitable physical, mechanical and thermal properties for food packaging, and could possibly be used in the place of expanded polystyrene (EPS) foam.