Volatile Compounds Identified in Preserved Duck Eggs

Abstract

Although egg is one of the most popular foods in the world, few studies on the flavor of eggs have been reported and no specific compounds have been determined to be responsible for characteristics egg flavor. MacLeod and Cave are the pioneers to investigate the egg flavor (MacLeod and Cave, 1975, 1976). Using a simultaneous distillation and extraction method, they have identified over 100 volatile flavor compoounds in cooked hen‐s eggs. Those classes of compounds are hydrocarbons, furans, pyrazines, pyrroles, carbonyls, alcohols, indans, and benzenes. A review of egg flavor was later published by Maga (Maga, 1982), where he discussed the previous studies on the flavor of whole egg, egg yolk, fermented egg, and dehydrated egg products, etc. Two paper on scrambled egg flavor were recently published (Matiella and Hsieh, 1991, Warren et al., 1995), and some sulfur-containing compounds such as dimethyl sulfide, thirane, dimethyl disulfide, and tetrahydrothiophene were identified. When the eggs were heated at 200°C, some sulfides, nutriles, thiazoles, thiophenes, pyrides and more pyrazines were produced form eggs (Umano et al., 1990).

Volatile compounds of preserved duck eggs and cooked duck eggs were isolated by a simultaneous steam distillation/extraction method and analyzed by GC and GC/MS. Flavor profiles in both egg products were compared. The preserved duck eggs have a fresh sulfur, weak roasty, and alkaline odor. Pyrazines, hydrogen sulfide, and ploysulfur compounds were exclusively identified in the preserved duck eggs, while more long chain aldehydes existed in the cooked duck eggs.