Flavor quality of food

The flavor quality of food is a primary factor involved in a consumer s decision to purchase a food item. Therefore, food technologists require a thorough understanding of how flavor deteriorates if they are to prepare products that consumers will purchase repeatedly. This knowledge is particularly important in meat and meat products, since the deterioration of meat flavor is a serious and continual process (1-4) that involves both the loss of desirable flavor components 4,5) and the formation of off-flavor compounds (6-9) many of which are associated with lipid oxidation (10). 

Reineccius G., Instrumental means of monitoring the flavor quality of foods. Acs. Symp. Series., 631, 241-252, 1996. 

Instrumental Means of Monitoring the Flavor Quality of Foods... 

Both 15 and 16 are involved in plant defense, they may have a role in the flavor spectrum, and their concentration can influence the nutritional safety and quality of food crops. For example, Soledade and colleagues demonstrated the crucial role of indole-3-aldoxime in the biogenesis of cruciferous defense against fungi-induced plant diseases. This is achieved by inserting the indolyl moiety via indole-3-aldoxime, which is a precursor of several secondary chemical defense metabolites of cruciferae. 

Dupuy and coworkers have reported a direct gas chromatographic procedure for the examination of volatiles in vegetable oils (11). peanuts and peanut butters (12, 13), and rice and com products (14). When the procedure was appTTed to the analysis of flavor-scored samples, the instrumental data correlated well with sensory data (15, 16, 17), showing that food flavor can be measured by instrvmental means. Our present report provides additional evidence that the direct gas chromatographic method, when coupled with mass spectrometry for the identification of the compounds, can supply valid information about the flavor quality of certain food products. Such information can then be used to understand the mechanisms that affect flavor quality. Experimental Procedures... 

Subramanian, A., Harper, J. W., and Rodriguez-Saona, L. E. (2009b). Rapid prediction of composition and flavor quality of Cheddar cheese using ATR-FTIR spectroscopy. I. Food Sci. 74, C292-C297. 

Ahmed, E. M. Dennison, R. A. Shaw, P. E. Effect of selected oil and essence volatile components on flavor quality of pumpout orange juice. J. Agric. Food Chem., 1978, 26, 368-372. 

Quality of food products is nearly always based on esthetic values, such as color, texture and consistency, as well as physiological thresholds and sensitivities to taste, flavor and aroma. Ultimately the acceptance of foods and their products is dependent upon the physiological or biochemical state of the product, however, the subjective evaluations cannot be ignored except in times of hunger and famine. 

Ethylfuran was identified in pasteurized crahmeat. 2-Pentylfuran was also identified in all three samples and contributed negatively to the flavor quality of both crayfish and blue crab. Limonene was identified in all three samples and possibly entered these crustaceans via food ingestion. Limonene has been found as a volatile component in fish (24), krill (28) and shrimp (13). 

A substantial amount of information on volatiles can be obtained with less than 30 g of each of these samples in a direct DHS/GC/MS analysis. DHS operation sweeps volatile flavors from the surface of food samples in a similar way as we sniff for the volatile flavors of a food. DHS does not require high sampling temperature or solvent for extraction and may be considered as a lcw-artifact arcma sampling technique. The concentrating effect of DHS provides better sensitivity than static headspace sampling. Techniques such as GC-coupled aroma perception and GC/MS identification can be used to complement other approaches in improvement of flavor quality of a variety of products. 

Lipids can degrade in frozen systems by means of hydrolysis and oxidation. Lipid oxidation is indeed one of the major causes of food spoilage. It is of great economic concern to the food industry because it leads to the development of various off-flavors and off-odors. In addition, oxidative reactions can decrease the nutritional quality of foods (Nawar, 1996). 

Sensory evaluation provides information most closely associated with the quality of food lipids. Flavor or odor defects may be detected by panelists before they are recognised by chemical or instrumental methods. For example, the fishy and grassy taste produced in linolenic acid-containing oils such as soybean oil occurs at very low levels of oxidation only detected by sensory analyses. The limitations of this method are poor reproducibility and high cost of panelists and the necessary facilities. The recommended approach is to use more reproducible chemical or instrumental methods to complement or support the sensory analyses (Frankel 1998). 

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