Effect Of Different Salt Ions On The Formation Of Nuclear Induced Whey Protein Concentrate Nanofibers

Whey protein concentrate?WPC?usually forms nanofiber polymer under the condition of low p H value,low ionic strength,high temperature and long time heating.Our previous research results showed that nuclear induction was another way to form nanofiber polymer.The addition of salt ions has a strong destructive effect on the formation of nanofibers in the conventional way,while the nuclear induced way has a certain improvement on the salt tolerance.Therefore,from the differences of the ability of different concentrations about NaCl to form nanofibers in three ways:spontaneous,nuclear induction?homogeneous nuclear induction,secondary nuclear induction?and multiple nuclear induction,the effects of NaCl on the kinetics of nuclear induced polymerization were systematically analyzed.Through the change of Th T fluorescence intensity,four salts?NaCl,KCl,Mg Cl₂,Ca Cl₂?with the same anion and different cations were studied.The influence of anions and cations on the formation of fibers was analyzed by means of thermogravimetry,surface charge,infrared spectroscopy and X-ray photoelectron spectroscopy.The specific research results are as follows:Effect of NaCl on kinetics of nuclear-induced polymerization The addition of NaCl decreased the ability of nuclear induction.The tolerance of nuclear induction mode to NaCl is higher than that of spontaneous mode,and the amount of fibers formed by nuclear induction mode is in low concentration?homogeneous nucleus is in the range of 0-50mmol/L,secondary nucleus is in the range of 0-75 mmol/L?is higher than the amount of fibers formed spontaneously without NaCl,but also has the ability of induction.In the high concentration condition,it gradually loses the ability of induction.In the nuclear induction mode,the secondary nuclear induction is more tolerant to salt.The effect of NaCl on nuclear induction was weaker than that of spontaneous induction.Effect of NaCl on fiber forming ability of multiple induction samples The effect of NaCl addition on the formation of fibers was different.The ability of salt tolerance of nuclear induction is higher than that of spontaneous induction.With the increase of NaCl concentration,the ability of nuclear induction will be reduced or even lost.When NaCl is not added,the amount of the first five induced fibers is higher than that of spontaneous induction.Only induced 6 loses the ability of induction.When 50m M NaCl is added,induced 4 and induced 5 samples that did not lose the ability of induction when salt is not added lose the ability of induction.When 100m M NaCl is added,induced 4 and induced 5 samples lose the ability of induction When NaCl was used,only induced 2 had induction ability.Influence of different cations on the ability of multiple induction samples to form fibers When four salts?NaCl,KCl,Mg Cl₂,Ca Cl₂?with the same anion,different cations and the same anion concentration are added,the amount of fibers formed by samples with the same induction times is different,and 50m M is added When the concentration of Cl^-was the same,the inhibition of divalent cations on fibers was greater than that of monovalent cations.Effects of four salts on surface charge and thermal stability of fibers The addition of salt can inhibit the ability of the sample to form fiber,and the degree of inhibition is different with different salt concentration and type.The amount of fiber determines the level of potential.Without NaCl,the change trend of potential of the sample is the same as that of fiber.The potential increment of the sample with divalent cations is larger than that of the sample with monovalent cations.It can be seen from the results of TG that there is a positive correlation between the fiber quantity and the mass loss rate in the process of thermal decomposition.Relationship between salt ion binding amount and fiber formation The combination of anions and cations with the sample inhibited the formation of the fiber and reduced the amount of the fiber.The changes of N-H bond and O-H bond show that the combination of anion and cation of NaCl with amino and carboxyl groups is more than that of Ca Cl₂ at the same concentration of Cl^-.The amount of Cl^-binding in the sample with NaCl addition is larger than that of the sample with Ca Cl₂ addition,but the amount of fiber is only reduced very little.It is speculated that the inhibition of Cl^-on fiber is very small,and the increase of the amount of cation binding to sample significantly reduces the amount of fiber,and the inhibition of fiber is greater.The inhibition of Ca²⁺on the fibers was greater than that of Na⁺.