AN EMPIRICAL APPROACH FOR ASSESSMENT OF SAFE STORAGE PERIOD FOR BUTTON MUSHROOM (AGARICUS BISPORUS) BASED UPON COLOR CHANGES UNDER MODIFIED ATMOSPHERE PACKAGING

Abstract

ABSTRACT White button mushroom accounts for 35–45% of the total mushroom produced in the world. Modified atmosphere packaging or MAP is a technology that, along with low temperature storage, helps in extending the shelf life and maintenance of quality of the produce packaged in polymeric films. The present study mathematically modeled the various transport processes associated with the mushroom under MAP at 15C and 75% relative humidity (RH) using the enzyme kinetics approach. Low density polyethylene (LDPE), polypropylene (PP) and oriented polypropylene (OPP) films were used to pack the mushroom. Numerical solutions to the transient state equations were programed in a computer programing language to predict the in-pack gaseous partial pressures at any instant of time. The model was experimentally validated, and a simple qualitative tool based upon optimum whiteness of mushroom was developed using the predictions to determine the safe period of storage. The predicted and experimental in-pack partial pressures of O2 and CO2 were in fair agreement with each other. In the OPP film packages, the O2 and CO2 levels stabilized around 6.87 and 12.93 kPa, respectively. Whereas, O2 levels decreased drastically in LDPE and PP film packages. A combination of predicted in-pack environment in all the film packages, storage time and whiteness of mushroom led to the conclusion that mushrooms can be stored safely for 32, 44 and 108 h in the gaseous environment available in the LDPE, PP and OPP film packages, respectively. PRACTICAL APPLICATIONS The empirical approach followed in this study through assimilation of various transient state in-pack variables with a single qualitative attribute of mushroom can serve as a measure of assessment of the mushroom's safe storage period under modified atmosphere packaging. Further, the mathematical approach suggested in this study can also serve as a benchmark for its application to other fruits and vegetables, taking into consideration their respective limiting qualitative characteristics. Thus, the results detailed in the study can be easily applied for their direct practical application during storage as well as for further academic exercises.