Milk Source Of Protein And Vegetable Oil And Its Application In Emulsified Sausages

Fat substitutes are important additives in food processing. Recently, pre-emulsions made from oil, protein and water have been researched extensively as fat substitute in meat processing. With good physical stability, water holding capacity and solubility, pre-emulsions have been used in fermented sausage and Frankfurt in order to reduce the fat content and improve fatty acid profile. Pre-emulsions stabilized with sodium caseinate and soy protein isolate have been studied a lot, while application pre-emulsions stabilized with whey protein replacing pork back-fat in chicken breast emulsified sausage have not been reported.In this study, firstly, emulsions made from different protein(sodium caseinate and whey protein),oil contented different saturated fatty acid and water, then the ability of emulsifying of different emulsions were compared. Secondly, pre-emulsions made from oil, whey protein and water were used as pork back-fat replacers in low-fat emulsified sausages. Composition and technological properties were analyzed. The contents and results were as follows:1. Study on the emulsifying properties of the emulsions contenting whey protein and sodium caseinateEmulsions were made from different contenting of protein (1%、2%、3%、4%、5%、 6%)、oil contenting with different saturated fatty acid(8% and 16%) and water, and then comparing the emulsifying stability of different emulsions use different methods. The results indicated three laws:the first, with the concentration of protein increasing, the emulsions’ emulsifying stability were significant improving (P<0.05). The second, the concentration of protein was low to 3%, the emulsions contenting with whey protein was more stable than the one contenting sodium caseinate. While the concentration of protein was high to 3%, the emulsions contenting sodium caseinate were more stable than the one contenting whey protein. The third, the emulsions which contented with high saturated fatty acid(16%) were more stable than the emulsions contenting low saturated fatty acid(8%).2. Pre-emulsion stabilized with whey protein as pork back-fat substitute in low-fat emulsified sausagesPre-emulsions stabilized with whey protein were used as pork back-fat replacers in low-fat emulsified sausages. Composition (proximate analysis and fatty acid profile), technological properties (processing loss, WHC, color, pH and texture) and the water mobility of the sausage were analyzed as affected by the percentage of fat replacer (1/3,1/2, 2/3). Results indicated that pH, moisture, protein, ash content of emulsified sausages became larger and fat content became smaller with the increase of replacing level. Compared to control sample, sausages produced with pre-emulsions had high levels of processing loss and low levels of WHC excepted from 2/3 replacer. Also, sausages produced with pre-emulsions had higher L* and b* values while the a* values was lower(P<0.05). Sausages with the pre-emulsions had higher cohesiveness, springiness, chewiness and lower hardness (P<0.05), while the gumminess was not significant changing (P>0.05). Emulsified sausages had unpleased flavor when all pork back-fat was replaced by the emulsions and it was not accepted by customers. The suggested percentage of fat substitution was 75%. Compared to control sample, sausages produced with pre-emulsions had high percentage of T24 and low percentage of T22 (P<0.05), while the percentage of T21 and T23 was not significant changing (P>0.05). Considering the 2/3 replacer had good processing loss, WHC, texture and so on, so it was chosen the most suitable replacer of all.