The aim of this study was to evaluate a headspace solid-phase microextraction gas chromatography (HS-SPME-GC) method for monitoring lipid oxidation in muscle foods. Oxidation in muscle foods was determined in a model system consisting of turkey muscle washed with a sodium phosphate buffer (pH= 5.6), to concentrate the myofibrillar proteins and membrane lipids. Lipid oxidation was determined by changes in propanal and hexanal concentrations by HS-SPME-GC along with thiobarbituric acid reactive substances (TBARs). To prevent oxidation of the washed muscle during analysis, an antioxidant mixture (EDTA, Trolox and propyl gallate) was added immediately before HS-SPME-GC. After antioxidant addition, propanal and TBARs concentrations did not increase during subsequent storage, indicating that the antioxidants stopped oxidation during HS-SPME-GC analysis. During storage of the washed muscle, it was observed that propanal concentrations increased, while hexanal significantly decreased after 8 h of further storage. While hexanal formation would be expected to be slower than propanal since most -6 fatty acids are more oxidatively stable than -3 fatty acids, it was surprising that decreases instead of increases in hexanal were observed. To determine if the aldehydes were becoming covalently conjugated to the amines and sulfhydryl groups in the washed turkey muscle proteins leading to reduced volatility, hexanal and propanal were added to either phosphate buffer or washed turkey muscle and their concentrations were monitored over time. Headspace concentrations of neither propanal nor hexanal decreased in the phosphate buffer during storage for 24 h. However, in the washed turkey, headspace propanal decreased 47% and hexanal decreased 84% after 24 h of storage. In conclusion, TBARs were found to be a more sensitive marker of lipid oxidation than headspace hexanal and propanal in washed turkey muscle. This could be due to the reaction of propanal and hexanal with proteins in muscle foods, resulting in decreased volatility.
G. Pignoli, R. Bou, M. T. Rodriguez-Estrada, E. A. Decker (2008). Time-dependent interaction of saturated aldehydes in washed turkey muscle added with different antioxidants. FRANKFURT : Euro Fed Lipid.
Time-dependent interaction of saturated aldehydes in washed turkey muscle added with different antioxidants
PIGNOLI, GIOVANNI;RODRIGUEZ ESTRADA, MARIA TERESA;
2008
Abstract
The aim of this study was to evaluate a headspace solid-phase microextraction gas chromatography (HS-SPME-GC) method for monitoring lipid oxidation in muscle foods. Oxidation in muscle foods was determined in a model system consisting of turkey muscle washed with a sodium phosphate buffer (pH= 5.6), to concentrate the myofibrillar proteins and membrane lipids. Lipid oxidation was determined by changes in propanal and hexanal concentrations by HS-SPME-GC along with thiobarbituric acid reactive substances (TBARs). To prevent oxidation of the washed muscle during analysis, an antioxidant mixture (EDTA, Trolox and propyl gallate) was added immediately before HS-SPME-GC. After antioxidant addition, propanal and TBARs concentrations did not increase during subsequent storage, indicating that the antioxidants stopped oxidation during HS-SPME-GC analysis. During storage of the washed muscle, it was observed that propanal concentrations increased, while hexanal significantly decreased after 8 h of further storage. While hexanal formation would be expected to be slower than propanal since most -6 fatty acids are more oxidatively stable than -3 fatty acids, it was surprising that decreases instead of increases in hexanal were observed. To determine if the aldehydes were becoming covalently conjugated to the amines and sulfhydryl groups in the washed turkey muscle proteins leading to reduced volatility, hexanal and propanal were added to either phosphate buffer or washed turkey muscle and their concentrations were monitored over time. Headspace concentrations of neither propanal nor hexanal decreased in the phosphate buffer during storage for 24 h. However, in the washed turkey, headspace propanal decreased 47% and hexanal decreased 84% after 24 h of storage. In conclusion, TBARs were found to be a more sensitive marker of lipid oxidation than headspace hexanal and propanal in washed turkey muscle. This could be due to the reaction of propanal and hexanal with proteins in muscle foods, resulting in decreased volatility.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
