Effects Of Soybean Protein Isolate Combined With Ultrahigh Pressure On The Gelation Characteristics Of Low-sodium Minced Pork

Low sodium meat products have been a challenge for the meat industry due to the growing demand for healthy meat products.However,directly reducing the sodium content in meat products will affect the dissolution of myofibrin,thus reducing the quality of meat products.How to ensure the quality of meat products while minimizing the sodium content is an urgent problem to be solved.Soy protein isolate is a kind of non-plant protein rich in a variety of essential amino acids.Due to its good gelation,stable emulsification,strong water and fat retention,it can be added to meat products to combine with low sodium to form a better gelation structure for minced pork.Potassium chloride is probably the most common salt substitute in low-salt or low-sodium foods,with a replacement ratio of no more than 50%.If soy protein isolate is added to meat products and potassium chloride is used as a substitute,the appropriate replacement ratio will be studied to reduce sodium content to a greater extent.High pressure treatment is a new technique to improve the quality of meat products by inactivating enzymes,reducing the number of microorganisms and denaturating proteins,which has great advantages for the production of low-sodium meat products.It can be used to reduce the cooking loss of meat products,improve the structure of meat products,and make low-sodium meat products rich in better quality characteristics.Based on ground pork as the research object,this paper discusses the high pressure treatment combined with soybean protein isolated and potassium chloride to replace sodium chloride on the physical and chemical properties,rheological property of minced pork and water distribution and the influence of protein conformation,in-depth study of the subject is helpful to the improvement of the theory of low sodium gel,guide the development and production of low sodium gel type of meat.The main research contents and results of this paper are as follows:1.Effects of soy protein isolate and sodium chloride on the gelation characteristics of minced porkIn this study,the changes of physico-chemical,rheological properties and water distribution state attributes of minced pork with various amount of NaCl?1%and 2%?and soy protein isolate?3%and 6%?were investigated.The level of NaCl and soy protein isolate significantly affected the color,cooking yield,texture,microstructure,rheological properties and water distribution state.The cooking yield and hardness of minced pork were increased significantly?P<0.05?with the NaCl and soy protein isolate improved,L^*value also was increased significantly?P<0.05?except 2%NaCl content.At the 2%NaCl content,the springiness and cohesiveness of minced pork with 6%soy protein isolate were decreased significantly?P<0.05?.Improved the levels of NaCl and soy protein isolate,increased the denaturation temperature of myosin,formed more compact and continuous structures during the heating,and the initial relaxation times of T_2b,T₂₁1 and T₂₂2 were significantly quicker?P<0.05?,the peak ratios of P₂₁1 were significantly increased and P₂₂2 were significantly decreased?P<0.05?.Overall,the soy protein isolate enabled lowering the NaCl content of frankfurters with desirable quality.2.The effects of potassium chloride partial substitution of sodium chloride on the characteristics of pork minced pork gelatinKCl was selected to replace the traditional sodium salt.On the premise of adding 6%soybean protein isolate and 1%NaCl,the substitution ratio of KCl was 0%,10%,20%,30%and 40%,respectively.The water-retention,color difference,texture,sensory evaluation and rheological properties of minced pork gelation were analyzed.The results showed that,compared with the control group with NaCl added alone,with the increase of KCl substitution,the cooking rate of gel had a decreasing trend at 40%substitution ratio,but there was no significant difference,and there was no significant difference between the groups?P>0.05?.The hardness and elasticity of minced pork gel fluctuated slightly,but there was no significant difference on the whole,and there was no significant difference in cohesiveness and mastication?P>0.05?.There was no significant difference between gel color difference and G'?P>0.05?,and there was no significant difference between gel color difference and G'between different substitution ratios?P>0.05?.The cooking rate and texture characteristics and overall acceptability of minced pork gel decreased when potassium chloride was 40%.The results provide reference for low sodium meat products.3.Effects of high pressure on gelation characteristics of low sodium minced porkIn order to explore the effects of high pressure,soybean protein isolate and potassium chloride binding on the physicochemical properties of minced pork with low sodium,the changes of water retention,color difference,texture and rheological properties of minced pork were analyzed under different pressure levels?0.1⁴00MPa?and pressure holding for 10 minutes at 10?.Results show that compared with the control group 0.1MPa,along with the increase of stress level,the minced pork gel water retention increased significantly,peaked at 200MPa,L*value increases after the first decreases,and the lowest when 200MPa,hardness and elasticity of highest during 200³00MPa,no significant difference between the two groups?P>0.05?,and rheological properties of the energy storage modulus was also significantly increased with the increase of stress level,peaked in 200MPa.This study shows that 200MPa pressure treatment can significantly improve the quality of low-sodium minced pork products,which provides a theoretical basis for the development of low-sodium meat products.