Effects Of Curcumin On The Stability And Digestibility Of Myofibrin Emulsion Gel System

Curcumin（CUR）is a fat-soluble polyphenolic compound mainly obtained from the rhizome of turmeric.It has antibacterial,antioxidant,anti-inflammatory and other biological activities.However,CUR has problems such as low water solubility,poor stability,and low bioavailability,which affect its application in the food industry.In this paper,soybean oil was used to load the active ingredient CUR to study the effect of CUR active ingredients on the emulsification and thermal gel functional properties of myofibrillar protein（MP）.On the basis of screening out the optimal amount of CUR added in the composite system,the effects of its digestion characteristics and heating,light,UV,p H,ionic strength and other conditions on the stability of CUR were studied,and the effect of the composite system on the quality of emulsified sausage in practical application was discussed.The main research conclusions are as follows:1.The effect of CUR addition in the composite system on the emulsification properties of MP:With the increase of CUR addition,the emulsification activity gradually increased（P<0.05）,which was opposite to the trend of emulsification stability.When the addition amount is 200 mg/L,the hydrophobicity is the lowest,the particle size is the smallest,the absolute value of the zeta potential is the largest,and the gelation rate is the fastest at 14.83±0.33 Pa/℃.With the increase of CUR content,the antioxidant capacity of the composite system was significantly improved,and the DPPH free radical scavenging rate increased from 1.52%to 8.13%,but the particle size of the emulsion increased and the fat droplets aggregated when the addition amount was 400 mg/L.2.The effect of CUR addition in the composite system on the properties of MP gel:With the increase of CUR addition,the yellowness value increased significantly.The water retention is the best when the addition amount is 200 mg/L.The relaxation time T₂₁first increased and then decreased（P<0.05）,T₂₂increased and T₂₃decreased relatively.The peak area ratio of P₂₁is about 1%,and P₂₂is about 85%,accounting for the largest proportion of the total water content.In addition,when the addition amount of CUR was 400 mg/L,the voids of the gel network increased,and irregular pores appeared,which had an adverse effect on the structure of the emulsified gel.3.Influence of external environmental conditions on the stability of composite system:when the p H value is 6.0,the minimum emulsion particle size is 1.09±0.93μm,and the maximum absolute value ofζ-potential is 44.88±3.00 m V.The emulsion stability was the highest when the ion concentration was 0.6 mol/L.Heating at 80°C for 10 h,the CUR retention rate can reach 50%.The retention rate of UV irradiation for 10 h was 47%.The retention rate of incandescent lamp irradiation for 10 h can reach 55.1%.It shows that the composite system has certain protection value for CUR.The changes in particle size and zeta-potential of the emulsions with and without CUR addition during the simulated digestion process were the same.In the late stage of digestion,the protein-encapsulated oil phase structure has completely disappeared.The bioavailability of CUR in the complex was 61.28±1.77%.4.Application of compound system in emulsified sausage:Use compound to replace backfat in emulsified sausage.With the continuous increase of replacement ratio,the cooking loss,water holding capacity,p H value,hardness and chewiness of emulsified sausage all decreased（P<0.05）.The values of yellowness,elasticity,cohesion and recoverable deformation were significantly increased（P<0.05）.It shows that proper substitution can improve the taste of the product,but when the addition amount is more than 13%of the total amount,the hardness of the product will decrease,the chewiness will decrease,and the taste will become worse.Taking into account comprehensively,the ratio of complex to backfat fat in emulsified intestine is2:3 is the most suitable.