EFFECTS OF PACKAGING AND STORAGE-CONDITIONS ON VOLATILE COMPOUNDS IN GAS-PACKED POULTRY MEAT

Volatile compounds released by raw chicken legs packed in modified atm osphere packages were determined in order to develop a spoilage indica tor for monitoring the shelf-life of raw chicken, Internal spoilage in dicators would react with compounds released during chemical, enzymati c and/or microbial spoilage reactions. The effects of four packaging f actors (headspace volume, oxygen transmission rate of the package, res idual oxygen and carbon dioxide concentration) and three storage facto rs (temperature, illumination and storage rime) on the amounts of vola tile compounds in the headspace of gas packages containing two chicken legs were studied. Statistical experimental design was applied and a linear screening design comprising 18 experiments (fractional factoria l) was utilized. Volatile compounds in package headspace were determin ed by gas chromatography-mass spectrometry using the dynamic headspace technique. The results were compared with the results of sensory eval uation and microbial determinations. The headspace of stored packages was dominated by the following compounds: butene, ethanol, acetone, pe ntane, dimethylsulphide, carbon disulphide and dimethyl disulphide. In modelling, some interaction terms and squared terms were needed in ad dition to linear terms. The main factors affecting the amounts of etha nol, dimethyl sulphide, carbon disulphide and dimethyl disulphide were storage time and temperature. Other factors had only minor importance , carbon dioxide concentration and headspace volume being the most sig nificant package parameters. The same four factors also had rite great est effects on the odour of chicken legs.