PERMEABILITY ESTIMATION OF A MODIFIED ATMOSPHERE PACKAGE FOR “HASS” AVOCADO STORAGE

Abstract

Refrigeration and modified atmosphere packaging (MAP) are useful technologies to preserve and extend the shelf life of fruit and vegetables. The packaging industry aims to permanently develop technologies that provide suitable conditions for the commercialization of fruit and vegetables. Due to the market demands, packages were developed to protect fresh products from quality loss and to prolong shelf life. MAP is not always used for horticultural products in México. There are few cases where packages are designed for a specific fruit. Sometimes, the same package is used for different fruit; therefore, there is no adequate control of the gas concentration during storage, causing a faster deterioration. The objective of this research was
to simulate the O₂ and CO₂ concentrations of “Hass” avocado (Persea americana Mill.) stored in a MAP with different O₂ and CO₂ permeabilities, based on the non-stationary state mass balances for the gas concentrations and the enzymatic kinetics for O₂consumption and CO₂ production rates. A closed system and inhibition models were used to determine the respiratory  behavior, and the correspondent kinetic parameters were obtained  through a regression analysis. The O₂ and CO₂ concentrations inside a MAP in function of time were satisfactorily (R²>0.97)  simulated at 8±1 °C using a competitive inhibition model.  Through simulation, different permeabilities were tested to ensure lower O₂ and higher CO₂ concentrations levels inside the MAP. With the estimated O₂ (2.9x10^–5 mL cm cm^-2 h^-1 cmHg^-1) and CO₂ (4.1x10^-5 mL cm cm^-2 h^-1 cmHg^-1) permeabilities, the gas concentrations inside the ackage were simulated for the system to reach stable concentrations of 10.0 and 9.5 mol% for O₂ and CO₂ after 240 h of storage. These permeabilities could improve the internal atmosphere and extend the “Hass” avocado shelf life when stored under MAP at 8±1 °C.