| Noodles have an indispensable position in the daily diet of human beings and are deeply loved by consumers.However,the nutritional value of ordinary noodles is low,and the storage resistance of fresh noodles is very poor,and the storage method of fresh wet noodles also has great defects.Therefore,in order to improve the storage performance and nutritional value of fresh wet noodles,in this study,protein,starch and polypeptide were extracted from the fruit of Millettia dielsiana Harms,which has high nutritional value.Then the protein and starch were used as the wall materials of microcapsules,polypeptide of Millettia dielsiana Harms and antibacterial substance Nisin were used as the core materials to prepare a W/O/W microcapsule.The properties of microcapsules were characterized to determine the best formulation of microcapsules.Finally,the effects of microcapsules on cooking quality and storage quality of fresh wet noodles were investigated.The main results are as follows:(1)Ultrasonic and microwave assisted methods were used to optimize the extraction rate of Millettia dielsiana Harms protein.The effects of different ultrasonic power and microwave power on the extraction rate were investigated.When the temperature was45 ℃ and the time of ultrasonic and microwave treatment was 15 min respectively,the extraction yield reached the highest 15.36% ± 0.02% under the power combination of ultrasonic at 30 W and microwave at 30 W,which was 5.65% higher than that of the blank group.SDS-PAGE results showed that the protein contained more 7S and 11 S,which had good processing potential.Millettia dielsiana Harms polypeptide concentrated around 1.2k Da,showing good antioxidant activity(DPPH free radical scavenging rate 68.09% ±0.86%).(2)The W/O emulsion was prepared with citrus essential oil,Nisin and Millettia dielsiana Harms polypeptide,and the inclusion rate reached 28.21% ± 0.457% when the oil-water ratio was 5:1.Subsequently,Millettia dielsiana Harms protein and its starch were used as the microcapsule wall materials,and W/O/W microcapsules were prepared by secondary embedding of W/O emulsion by complex coagulation method.When the core material amount was 5 g,wall material amount was 100 m L and the wall material ratio was1:1,the highest embedding rate was 61.47% ± 3.07%.The microcapsules formed by this method had good morphology and good stability.The Zeta potential value was-24.73 ±1.86 m V,the particle size was 7.64 ± 0.22 μm,and the PDI was 0.52 ± 0.05.Further study found that there were van der Waals force,hydrogen bond and electrostatic interaction force between Millettia dielsiana Harms protein and its starch in the wall material.DSC curve showed that microencapsulation was beneficial to improve thermal stability.The microcapsules prepared with the best formula had good in vitro digestion performance,and the final release in the intestine was 84.8% ± 4.24%,which could achieve good protection in liquid environment.(3)W/O/W microcapsules were added to fresh noodles in different proportions to study the practical application effect of microcapsules in fresh noodles.The results showed that when the amount of microcapsules was less than 0.3%,the water absorption rate was increased and the cooking loss rate was reduced.In general,the addition of microcapsules can improve the stability of Nisin and increase the nutritional value of noodles and can be accepted by consumers.Among them,0.3% microcapsules have the best preservation effect on fresh wet noodles,which can extend the shelf life. |
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