Effect Of CaCl₂ On The Aggregates Of Whey Protein Concentrate With Adding Fibril Nuclei

Whey protein concentrate?WPC?nanofibril polymer was formed at t he conditions of under low p H,low ionic strength and high temperature for a long time.The homogeneous nuclei and secondary nuclei structure were formed during the fibril polymer formation process.The two kinds of nuclei induce WPC can accelerate the formation of fibril and increase the amount of fibril.CaCl₂ has the effect on the formation of fibril polymers.There is a lack of comparative study on adding CaCl₂ to two nuclei induce WPC polymerizations.This subject is mainly to explore the effect of CaCl₂ on the ability of two kinds of nuclei induce WPC polymerization.In this paper,whey protein concentrate was used as raw material to study the effect of CaCl₂ on the polymerization degree of different WPC polymers by measuring the gel time,texture and viscosity.Studying the influence of CaCl₂ on the induction process by Th T fluorescence intensity and polymerization amount.The effect of CaCl₂ on nuclei formation was studied.Exploring the main role of the changing the polymerization ability was Ca2+ or Cl-by comparing different ionic compounds,dialysis test and infrared spectroscopy.The difference in functional properties of CaCl₂ on nuclei formation,nuclei induction and fibril was explored by comparing the difference in functional properties of adding CaCl₂ in three stages.The results of the study are as follows:?1?Effect of CaCl₂ on the degree of polymerization of different WPC polymers : the degree of polymerization of WPC polymers was increased by adding CaCl₂.Adding CaCl₂ can significantly shorten the gel time and increase the hardness and viscosity.The effect of CaCl₂ on the degree of polymerization of the fibril polymer was greater than the conventional polymer.The two types of fibril formation?spontaneous and nuclei induction?were different.The gel time of nuclei induction was shorter than spontaneous and the hardness and viscosity values were higher than spontaneous by the influence of CaCl₂.The effect of CaCl₂ on nuclei induction polymerization was greater than spontaneous.The two nuclei inductions were different with CaCl₂.The hardness of homogeneous nuclei induction and secondary nuclei induction increased by 142.34% and 106.96%,and they were 2.04 and 2.34 times of the increase in spontaneous hardness at the concentration of CaCl₂ was 50 mmol/L.The gel time of the secondary nuclei induction to be the shortest,the hardness and viscosity values were also the largest,the homogeneous nuclei induction gel time was shortened the most,and the hardness was the highest.?2?Effect of CaCl₂ on nuclei induction process: the addition of CaCl₂ during nuclei induction has an effect on the formation of fibril polymers.The addition of CaCl₂ destroys the original structure of the fibril,but the degree of damage to the fibril polymer formed by the nuclear induction is lower than that of spontaneous.In terms of the amount of polymerization,the polymerization between proteins was promoted by adding CaCl₂.With the increasing concentration of CaCl₂,the amount of polymerization was increased.The protein polymerization of spontaneous,homogeneous nuclei induction and secondary nuclei induction increased 33.35%,39.74% and 35.42% by 50 mmol/L CaCl₂?10 h?,the homogeneous induction increased the most.In terms of fibril amount,the nuclei inducing ability was reduced by adding CaCl₂.The fibril polymer formed by adding CaCl₂ had lower Th T fluorescence intensity,but the homogeneous nuclei induction?0²0 mmol/L CaCl₂?and secondary nuclei induction?0³0 mmol/L CaCl₂?was higher than that of spontaneous?no CaCl₂?.The CaCl₂ tolerance of secondary nuclei induction was higher than that of homogeneous nuclei induction.The effect of CaCl₂ on the polymerization kinetics was calculated by the amount of polymerization and the fluorescence intensity of Th T.With the increasing CaCl₂ concentration,the polymerization rate of fibril polymer increased gradually,the activation energy decreased gradually.The effect of CaCl₂ on nuclei induction was greater than spontaneous.The rate of polymerization induced b y secondary nuclei was the largest and the increasing degree of homogeneous nuclei induction was the most by adding CaCl₂.The maximum hourly fluorescence increment?df/dt?obtained by spontaneous and homogeneous nuclei induction by CaCl₂ was advanced to heat treatment for 1 h.The tlag and t0.5max was shortened and the fmax was decreased by CaCl₂.?3?Effect of CaCl₂ on nuclei formation: CaCl₂ has different effects on two kinds of nuclei.The homogeneous nuclei has a certain inducing ability at 10 mmol/L,but lower than the homogeneous nuclei without CaCl₂.The inducing ability of homogeneous nuclei was gradually decreased with the increasing concentration of CaCl₂.The secondary nuclei has no inducing ability by CaCl₂.The degree of secondary nuclei loss inducing ability does not significantly differ with the change of CaCl₂ concentration.The effect of CaCl₂ concentration of 30 mmol/L on the homogeneous nuclei was equivalent to that of the secondary nuclei 10 mmol/L.When the CaCl₂ concentration was 40⁵0 mmol/L,the loss of homogeneous nuclei induction ability was higher than that of the secondary nuclei.?4?Effect of ions on fibril polymers: by comparing the effects of different ionic compounds on the fluorescence intensity of Th T during fibril formation process,it was found that there was no significant difference in the fluorescence intensity of Th T between CaCl₂ and MgCl₂ samples,it was indicated that the main role may not be cations.Compared with MgCl₂ and MgSO₄,it was found that when MgCl₂ was added at a protein concentration of 1.0 wt%,the fluorescence intensity of Th T was higher,and MgSO₄ was lower than control?sample without ionic compound?.The intensity of SO42-ion was higher than that of Cl-ion.Speculating the main role is anion because of the Th T fluorescence intensity decreased.The Ca2+ content was determined by dialysis.The binding of Ca2+ to the fibril polymer was weak,and the nuclei induction binding ability to Ca2+ was slightly higher than spontaneous.Infrared spectroscopy results showed that the addition of CaCl₂ during the induction process changed its N-H bond,presumably due to the combination of Cl-and N-H.Both Ca2+ and Cl-had a certain effect on the formation of fibril polymers,and Clplayed a major role.?5?Differences in the functional properties of CaCl₂: the influence of nuclei formation,nuclei induction and fibril were different.The hardiness was increased by adding CaCl₂ at first and second stages,and the foam stability and emulsion stability decreased.The degree of nuclei induction hardness improvement,foam stability and emulsification stability reduction at the first stage were all greater than those in the second stage.There was no significant change in the third stage of CaCl₂.Through the results of functional properties,it is found that the addition of CaCl₂ in the first stage has a destructive effect on the formation of nucle i,and its functional properties change the most.In the second stage,it has a certain influence on nuclei induction,and the degree of change in functional properties was second.For the mature fibril in the third stage,CaCl₂ has no obvious damage,so there was no obvious change in functional properties.