Optimisation of fish gelatin and red pitaya peel powder edible film production

Abstract

SummaryGrowing awareness of the environmental devastation caused by plastic packaging, particularly in the food industry, has led to the emergence of the concept of a renewable and environmentally safe consumable film as an alternative to plastic. Red pitaya (dragon fruit) peel (RPP), which has a high pectin content, can be used as an additional ingredient or co‐biopolymer to enhance the functional properties of fish gelatin (FG) edible film. Edible films were produced using casting techniques and varying concentrations of FG (3.2%–8.8% w/v) and RPP (0.2%–1.0%) with the aid of Central Composite Design (CCD) of Response Surface Methodology (RSM) by Design Expert 13's software. The optimal formulation consisted of 5.97% (w/v) FG and 0.45% (w/v) RPP. Increasing the concentrations of RPP and FG affected the thickness (0.18–0.36 mm), water solubility (46.72%–66.78%), brightness (60.04–79.02), redness (7.08–28.36), yellowness (2.48–8.44), and opacity (0.85–2.58) of the physical properties. Mechanical testing revealed a tensile strength between 2.76 and 9.34 MPa and a break elongation between 82.78% and 153.89%. The results suggested the physical and mechanical properties of RPP‐based films were greatly affected by concentration of gelatin.