A Study On The Oxidative Stability Of Fish Oil Emulsified In Surimi Gels

Surimi-based products have large amount of consumption in Japan every year.Kamaboko,as traditional surimi-based product,occupies a large part of market.On the other hand,PUFA contained in fish oil can significantly improve people's health.Human epidemiological and experimental animal studies have suggested that regular consumption of fish oil reduces morbidity as well as mortality due to cardiovascular diseases.Recently,many attempts have been made to produce processed foods containing fish oil,such as surimi-based products.PUFAs have great benefit for people's health,however it is easy to be oxidized during processing and storage.In previous study,on the other hand,oil could keep higher oxidative stability in an emulsion state when compared to a bulk state.And its oxidative stability was influenced by its particle size in an emulsion.The purpose of this study is to clarify oil oxidation in emulsified surimi gels by changing manufacturing method,and to provide theoretical basis for production.In this study,surimi gels were prepared by different conditions to clarify changes of fish oil oxidation.Generally,surimi gels were prepared by the following conditions1)Different mixing conditions(high-and low-speed mixing)under vacuum and air conditions;2)Different protein concentration in surimi gels;3)Oils with different melting point.By high-speed mixing condition of surimi gels,the oil was well emulsified and the small oil particles with diameter below 5 ?m were formed and remained stable even after heating,whereas the oil particle size by low-speed mixing was much larger and showed a little oily texture after heating.Although both peroxide value and thiobarbituric acid reactive substances values of each type of surimi gels increased with storage period in both cases of vigorous and mild mixing,the oxidation was prevented especially in the case of high-speed mixing under vacuum plus air.On the other hand,oil particle size decreased in surimi gels with protein concentration increasing,and the oxidative stability was significantly enhanced in higher protein concentration.In case of different oils,oil that has lower melting point could form smaller particle size and had higher oxidative stability.These results suggests that the level of oxidation of oil in surimi gel is affected by the levels of emulsification,and that the complete emulsification make fish oil to be protected.The mechanism of fish oil oxidation in surimi-based products needs to be clarified,and then scientific basis for food production will be provided.