Studies On The Quality Characteristics Of The Brine Of Water-Boiled Salted Duck

Flavor is one of the most important sensory properties of food. More reports on the flavor of traditional Chinese duck meat product-Nanjing water-boiled salted duck were presented. However little reports were on the study of the brine of water-boiled salted duck. So this study is intended to do some studies on the brine of different technics and different aging level which includes four kinds of brine, the fresh and aged brine of sweet-scented osmanthus duck and chen, which were studied by basic physical and chemical indicators, taste substances and volatile flavor compounds. The aim is to create a method, which can distinguish the fresh brine and the aged one and provide a theory basis in improving the processing technology and the regulation of flavor of water-boiled salted duck flavor. The contents and results are as follows.1. The crude protein content, fat content, pH value, the total number of colonies, TBA value, POV value and so on were analyzed and determinated in the four kinds of brine after curing and boiling. The results showed that pH value of the fresh brine gradually increased with the increase of frequency of use. pH value was respectively at about5.4and5.55after6cycles in the fresh brine of sweet-scented osmanthus duck and Chen, however which were respectively about in the small range of5.7to6.0and5.7to5.8in the aged brine of sweet-scented osmanthus duck and Chen. Thus pH can be one of the indicators that can distinguish the fresh brine and the aged one. If with the increase of frequency of use, the pH value changes within the5.7-6.0, that we will know the fresh brine has reached the level of aged brine. The total number of colonies, nitrite content, TBA values and POV values were lower in the fresh brine and the aged one than the national food hygiene standards in the corresponding provisions of the lowest concentration. It was secure and had no effect on human health. Therefore, the brine of curing was suitable for water boiled salted duck processing.2. Free amino acids and free fatty acids were the major taste compounds in the brine. However the nucleotide and its degradation products had little effect on the taste, which were the main flavor only in the brine of Chen. Glutamate was the main taste compound in the aged brine, which could be one of the indicators that can distinguish the fresh brine and the aged one. Threonine, isoleucine, histidine, tryptophan, cysteine, palmitic acid (C16:0), myristic acid (C14:0) and stearic acid (C18:0) were the main taste compounds in the fresh brine of sweet-scented osmanthus duck. Lysine, leucine, palmitic acid (C16:1), linoleic acid (C18:2), stearic acid (C18:0) and palmitic acid (C16:0) were the main taste compounds in the fresh brine of Chen. Phenylalanine, alanine, glycine, glutamic acid, serine, isoleucine, arginine, cysteine, myristic acid (C14:0), stearic acid (C18:0), oleic acid (C18:1) and palmitic acid (C16:0) were the main taste compounds in the aged brine of sweet-scented osmanthus duck. Phenylalanine, glutamic acid, leucine, isoleucine, valine,5’-AMP,5’-GMP, Hx,5’-IMP, linolenic acid (C18:3), linoleic acid (C18:2) and proline were the main taste compounds in the aged brine of Chen.3. The times of cooking and curing had great influence on the types and contents of volatile flavor compounds in the fresh brine and in the aged one. Hexanal had the highest concentrations and was the main body of the volatile flavor compounds in the aged brine, thus hexanal could be one of the indicators that can distinguish the fresh brine and the aged one. The main flavor compounds in the old brine were mainly alcohols, aldehydes, ketones, and oxygens.2-borneol, eucalyptus oil alcohol,6-methyl-5-heptene-2-one, hexanal, amyl alcohol, benzene, formaldehyde co-existed in the aged brine of sweet-scented osmanthus duck and Chen.1-memoxy-4-(2-propenyl)benzene,4-methoxybenzaldehyde, benzaldehyde, geraniol, linalool were the main body of the volatile flavor compounds in the fresh brine of sweet-scented osmanthus duck. Linalool, d-limonene,1-(4-methoxyphenyl)-2-acetone, benzaldehyde,2-heptanol were the main body of the volatile flavor compounds in the fresh brine of Chen.To sum up, pH, glutamate, hexanal were the indicators that can distinguish the fresh brine and the aged one. The times of cooking and curing had great influence on the flavor of the fresh brine and the aged one. Compounds changed in the dynamic process.