14B-13

H. Y. CHUNG, Bio. Dept., Food and Nutritional Sciences Programme, and Food Sci. Lab., The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong, China

Salting and drying of fish is a preservation practice with a long history. Two such specific preparation methods involving freshly salting and drying (F), and delayed salting and drying (D) of fishes are common in Hong Kong and in southern China. Some consumers claimed that stronger flavor was perceived in products prepared by method D than by method F.

The objective of this experiment was to validate the claim by qualifying, quantifying and comparing the volatile components of the Chinese herrings (Ilisha elongata), a popular salted-dried fish, prepared by F and D methods.

Triplicate fish samples (Ilisha elongata) prepared from methods F and D were purchased, cleaned and manually reduced in size before simultaneous steam distillation and solvent extraction (SDE). Extracts were analyzed by a gas chromatography/mass spectrometry. Compounds were verified with authentic standards.

A combined total of 115 components were identified in fishes prepared from the two methods. They included acids (6), aldehydes (25), alkanes (14), esters (9), ketones (19), miscellaneous compounds (3), oxygen-containing compounds (12), nitrogen-containing compounds (8), alcohols (17) and sulfur-containing compounds (2). Eighty and 77 compounds were found in D and F samples, respectively. Majority of the 42 common components found in both samples was similar in quantity (p > 0.05), but 32 of them from method D were with higher mean values than the rest from method F.

Method D generally provided a more intensive background flavor to the final products than method F. Major qualitative and quantitative differences observed in the rest of the volatile component suggested that the type of methods used would also have an impact on the subtle flavor produced in the final products. Overall, it is valid that stronger flavor was perceived in products prepared by method D than by method F.