Multi-response optimisation of gas composition in modified atmosphere packaging for postharvest quality retention of button mushrooms (Agaricus bisporus)

Button mushrooms (Agaricus bisporus) are highly susceptible to deterioration due to their rapid respiration rate, enzymatic browning and microbial load, which limit their shelf life. This study focused on optimising the gas composition of modified atmosphere packaging (MAP) to delay the physiological deterioration of button mushrooms using a simple lattice mixture design. The effects of oxygen (O2), carbon dioxide (CO2) and nitrogen (N2) at different combinations on colour (L*, a* and b*), firmness, physiological loss in weight (PLW), polyphenol oxidase (PPO) activity, antioxidant activity and microbial load were evaluated. Modified atmosphere packaging under optimised conditions significantly (p < 0.0001) maintained the post-harvest quality of button mushrooms compared with the control. The optimised condition (69 % O2, 10 % CO2 and 21 % N2) improved lightness by 7.5 % and firmness by 14.3 %, while reducing browning (a* by 22.0 %, b* by 8.5 %) and physiological weight loss by 93.5 %. The PPO activity decreased by 15.2 % and antioxidant activity increased by 17.7 %, indicating delayed senescence and oxidative deterioration. The quadratic Scheffe model revealed that all responses exhibited a strong correlation, showing a high R2 value (> 0.90) with a non-significant lack of fit. Numerical optimisation predicted an optimal gas composition of 69 % O2, 10 % CO2 and 21 % N2, with a desirability value of 0.725. Validation experiments closely matched predicted values, confirming that optimised MAP is an effective and practical approach for enhancing postharvest quality and extending the shelf life of button mushrooms.