Optimisation of O2 and CO2 concentrations to retain quality and prolong shelf life of ‘shelly’ mango fruit using a simplex lattice mixture design

The experimental design and gas mixture selection is of great importance in the definition of optimal gas concentrations for use in storage of fresh produce. The aim of this study was to optimise O2 and CO2 concentrations under controlled atmosphere conditions to understand the effect on quality and shelf life of ‘Shelly’ mango fruit stored at 13 °C for 28 d. This was achieved by designing three experimental points (gas compositions = O2, CO2 and N2) using simplex lattice mixture design to (i) determine single and interaction effects of gas compositions on selected quality parameters and (ii) determine the optimal gas combination in order to maintain quality and prolonging shelf life of ‘Shelly’ mango fruit. The estimated model parameters coefficients successfully categorised the single and interaction effects of O2, CO2 and N2 gas compositions. The selected quality attributes experimental data was fitted well using the canonical Scheffe type special cubic model, resulting in coefficient of Determination, R2 = 0.70 to 0.97. The low O2 and high CO2 in CA-2 managed to retard ripening and mass loss, and reduce fruit softening and chlorophyll degradation. Positive relationship was observed for linear effect in all quality attributes, while binary and ternary interaction effects varied across all the treatments. The optimal gas compositions for storage of ‘Shelly’ mango fruit in terms of selected quality attributes ranged between 5 and 8% O2 + 5–9% CO2 + 86–91% N2. The results highlight the potential use of simplex lattice mixture design to optimise CA storage conditions