| Salted duck egg is a traditional pickled egg product in China,which is widely welcomed by consumers.Well-preserved salted egg yolk has good oil and taste and is often used as filling for pastries.The salt content of salted duck egg white will gradually increase during the pickling process,and will produce a strong fishy smell.Since they are not directly edible,a large amount of salted duck egg whites are discarded every year.Although salted duck egg whites contain more than 6% salt,their protein content is not reduced,so they can still be considered a good source of protein.The proteins in salted duck egg whites can provide a good substrate for microorganisms to grow,thus the discarded salted duck egg whites not only cause waste of resources but also pollution to the environment.Currently,many researchers have used various methods and techniques to desalinate salted duck egg whites in order to extract the bioactive substances in them.The desalination methods and techniques for salted egg whites mainly include enzymatic digestion,desalination by soaking after gelation,desalination by ultrafiltration,desalination by electrodialysis and desalination by adding flocculants,etc.,but their production costs are high.Therefore,in this study,salted duck egg white liquid,egg white liquid and egg yolk liquid were used to obtain the best ratio for making salted duck egg white based egg sausage through formulation optimization and process investigation.The effects of different additions and different types of phosphates on the gelatinous properties of egg sausages were investigated.On this basis,the egg sausages were seasoned with spice juice and the flavor effects of spice juice on egg sausages were compared.The main conclusions were as follows:(1)Study on the base formulation and process optimization of egg sausage.The salted duck egg whites,eggs and water were compounded,and the optimal ratio of the base formulation was obtained by single-factor and orthogonal tests with texture,water-holding capacity,salinity and chromaticity as response indicators.The heating time and heating temperature were also optimized.The results showed that the hardness of the formula was 2657.45 g,the elasticity was 0.93 and the water-holding capacity was77.34%,and the color and salinity of the egg sausage were within the acceptable range when the amount of salted duck egg white added was 25 g,the amount of egg white added was 25 g,the amount of egg yolk added was 45 g,the amount of water added was15 g,the heating temperature was 90 ℃ and the heating time was 25 min.Therefore,this formulation and process were selected for subsequent optimization.(2)The effects of different phosphates on the gel characteristics of egg liquor were investigated.Three phosphates,sodium pyrophosphate(TSPP),sodium hexametaphosphate(SHMP)and sodium tripolyphosphate(STPP),and four compound phosphates,TSPP/SHMP,TSPP/STPP,SHMP/STPP and TSPP/SHMP/STPP,were selected to improve the gelation properties of egg intestines.The effects of single as well as composite phosphates on the thermal gelation properties of egg sausages were investigated by textural,water-holding,low-field NMR,rheological,and microstructural indices.The results showed that 0.5% TSPP had the best effect on the improvement of egg gelation.The hardness of the egg gel was 3121.32 g and the water holding capacity was 83.78%.(3)Research on the flavoring process of egg sausages.The recipe with the highest sensory score was obtained by adding spice juice for flavoring,optimizing the concentration ratio of spice juice,the amount of spice juice added and the amount of sucrose added.E-nose,E-tongue and flavor substance analysis were performed on the products before and after flavoring to investigate the differences in flavor and taste.The results showed that the highest sensory scores were obtained with a 3:15 spice juice concentration ratio,6% spice juice addition,and 1.7% sucrose addition.Comparing the e-nose,e-tongues and volatile flavor substances of egg sausages before and after seasoning,it was found that the briny flavor of egg sausages was more adequate after seasoning,and the volatile flavor substances produced many flavor-presenting substances in the spices,which effectively utilized the salted duck egg whites and were of great significance to the industrial development of egg products. |
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