Oxygen absorbers for extension of crackers shelf-life

Abstract

Applicability of oxygen absorbers for extending shelf-life of military ration crackers packaged in hermetically sealed tin cans and stored at 15, 25 and 35°C for up to 52 weeks was assessed. Lipid oxidation began immediately after baking. Storage temperature was the major factor affecting the rate of oxygen depletion within the can. Residual headspace oxygen of the crackers stored for 52 weeks with or without oxygen absorbers was 9, 3, 2 and 55, 41, 4 mL/L at 15, 25 and 35°C, respectively. Hexanal generation commenced shortly after baking and at 24 and 52 weeks was 6.1 and 8.8, 6.0 and 9.1, and 10.7 and 12.9 mg/kg at 15, 25 and 35°C, respectively. Oxygen absorbers reduced hexanal concentration significantly. Peroxide values were markedly affected by storage temperature. A lag period of 17 and 10 weeks was observed at 25 and 35°C, respectively. Sensory evaluations suggested that crackers stored without oxygen absorbers developed oxidative rancid odours after 24 weeks at 25 and 35°C. Independently of storage temperatures, no oxidative rancid odours were observed after 44 weeks with oxygen absorbers. The onset of oxidative rancid odours correlated with hexanal concentration above 6 mg/kg. Additional means are required to prevent oxidation and to extend shelf-life of crackers stored at 25°C or above. © 1998 Academic Press Limited.