MATHEMATICAL MODELLING ON STORAGE OF FRUITS AND VEGETABLES IN MODIFIED ATMOSPHERE PACKAGING (MAP) AND CONTROLLED ATMOSPHERE STORAGE (CA)

摘要

In modified atmosphere packaging (MAP) our aim is to find by mathematical models a steadyrnstate where the CO_2 production, O_2 consumption and H_2O transpiration rates of the commodityrnare proportional to the permeability rates of the respective gases through the packaging at arngiven temperature to reach maximum storage life.rnIn this way we abtain optimum concentrations of O_2, CO_2 and relative humidity, avoiding thernlimits put by fermentation, too fast ripening, senescence or appearance of disorders and decay.rnCommodity characteristics (maturity, dry matter, size), temperature, O_2 and CO_2 are known torninfuence respiratory activity in a package. We have to recognize an important interrelationrnbetween these different parameters and the changings in time.rnNature, thickness, surface, holes or micropores as well as gradients of CO_2, O_2 and H_2O at arncertain temperature and relative humidity determine permeability for gases.rnIn controlled atmosphere storage (CA). Next the fruit properties, also refrigerating characteristics (cooling capacity, delta t, air circulation and defrosting systems), and the used CO_2 regulating system, (CO_2 absorbers or N_2 flushing apparatus) are important parameters to realize the optimum temperature, O_2, CO_2, ethylene and relative humidity to maintain freshness of the produce.rnMathematical modelling on CA and MAP could help to frind not only the longest storage time, to reduce losses but also to find an optimal equilibrium between costs and benefits. New sensors are yet available or are to be developed.