L. Piergiovanni et P. Fava, MINIMIZING THE RESIDUAL OXYGEN IN MODIFIED ATMOSPHERE PACKAGING OF BAKERY PRODUCTS, Food additives and contaminants, 14(6-7), 1997, pp. 765-773
The total elimination of air represents a serious hurdle in modified a
tmosphere packaging of bakery products, due both to the high spin-rate
s of the packaging lines and, particularly, to the typical texture of
bakery products which retain large quantities of air inside their poro
us structure. Simulating the gas-flushing modified atmosphere packagin
g with laboratory equipment and measuring the oxygen concentration dir
ectly inside bread rolls, by means of a gas analyser connected with th
e internal portion, it was possible to follow the rate of atmosphere s
ubstitution, evaluating the effects of different baking treatments (7,
12 and 23 min at 230 degrees C) and the role played by different gase
s (nitrogen, argon, helium, nitrous oxide and carbon dioxide). The oxy
gen content inside the products, plotted versus time, led to typical l
ogistic 'dose-response' curves which made it possible to forecast the
time needed to reach established values of residual oxygen concentrati
on and to emphasize the effects of the different conditions used. The
gas properties particularly affected the rate of oxygen substitution a
nd the less water-soluble was the gas, the faster was the oxygen reduc
tion, the larger was the gas molecule, the slower was the process. Als
o baking time was shown to have, to a different extent, some measurabl
e effects on the rate of oxygen substitution and hence, its optimizati
on as well as the choice of gas mixture can contribute to improve modi
fied atmosphere packaging of bakery products.