Preparation and Characterization of Protein Bioplastics from Fish Waste Using Different Plasticizers

Abstract

The objective of this study was to develop protein bioplastics from fish waste using different types of plasticizers; polyethylene glycol, triethylene glycol and glycerol. Fish protein powders (head, skin, scales, viscera) were prepared from sardine byproduct (SBP), mackerel fillet powder (MFP) and mackerel byproduct powder (MBP). Protein content was characterized using proximate analysis and amino acids was determine using amino acid analysis. SBP was transform into bioplastics by using extrusion and compression moulding. The properties were characterized using thermo gravimetric analysis (TGA) and mechanical testing. Protein content in byproduct (SBP and MBP) were reasonable at approximately 40-60%. TGA result showed two stages of thermal decomposition starting at 230 °C. Below 230 °C, it was believed that protein denaturation occurred, involve structural or conformational changes from native structure without alteration of amino acid sequence. Further heating after 230 °C showed massive weight loss that lead to degradation. Mechanical properties was majorly influenced by plasticizers which improved the elongation at break properties. Glycerol was found to be the most effective plasticizer among those studied here, possibly because of its characteristics such as low molecular weight, high solubility in water, and large protein miscibility. The results obtained in this study showed that plasticizer types and concentration significantly improve film properties and enhances their suitability for single used of agriculture applications.