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Absorption kinetics of oxygen scavengers
Author(s) -
Tewari Gaurav,
Jayas Digvir S.,
Jeremiah Lester E.,
Holley Richard A.
Publication year - 2002
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1046/j.1365-2621.2002.00558.x
Subject(s) - scavenger , chemistry , absorption (acoustics) , kinetics , oxygen , scavenging , radical , analytical chemistry (journal) , nuclear chemistry , chromatography , antioxidant , organic chemistry , materials science , quantum mechanics , composite material , physics
The oxygen (O 2 ) absorption kinetics of six commercial O 2 scavengers were studied. The scavengers were placed in bags which were filled with 240 mL of air, 4.5 L N 2 + 15 mL of air, or 3.5 L CO 2 + 9 mL of air. The O 2 concentration in each bag was measured at hourly intervals for 8 h. The effects of variability among individual scavengers, initial O 2 concentrations of 20% or 500 ppm (0.05%), temperatures of 25, 12, 2 or −1.5 °C, and scavenger capacity on the O 2 absorption rate were determined. In addition, the effect of placing scavengers within over‐wrapped trays within bags, was examined. Rates of O 2 absorption varied by factors of up to 2 between individual O 2 scavengers of the same type, but rates of absorption by groups of four scavengers of the same type were similar. Low temperatures gave longer O 2 half‐life when compared with those at higher temperatures, e.g. O 2 half‐lives of 7.1 and 1.0 h at −1.5 and 25 °C, respectively, were obtained for one scavenger type. Shorter O 2 half‐lives were obtained in air than in N 2 atmospheres at the same temperature, e.g. O 2 half‐lives of 1.0 and 3.3 h in air and N 2 at 25 °C, respectively, were obtained for one scavenger type. The O 2 absorption reactions were of first order for both high and low initial O 2 concentrations. However, O 2 concentration was the primary limiting factor for O 2 absorption in atmospheres having O 2 concentration of 500 ppm because of the dominance of diffusion. Scavengers, when placed within over‐wrapped trays within bags had up to 12 times longer O 2 half‐lives, indicating that the O 2 permeable film acts as an O 2 barrier when pack atmosphere has low O 2 concentrations. To obtain consistent and reproducible results, it is recommended that multiple scavengers be used in a packaging system. The appropriate number should be based on scavenger type, desired O 2 absorption rate, storage temperature, and pack atmosphere (air/N 2 /CO 2 ).