The Study On Preparation Of Whey Protein Peptide Chelating Calcium And Its Microencapsulation

In this paper, whey protein, calcium, lecithin were used for raw materials, whey proteinpeptide chelating calcium and its microcapsules were prepared. The optimal conditions ofpreparing whey protein peptide, whey protein peptide chelating calcium and peptide-calciummicrocapsule was studied. The mechanism and the rule of whey protein peptide chelatingcalcium was explored, the nature and structure of the peptide-calcium microcapsule wasmeasured. Finally, the digestion performance of home-made products and commerciallyavailable calcium supplements were compared by in vitro digestion technology. The mainconclusions were as follows,1. The influence of various factors on the efficiency of whey protein hydrolysis wasstuded, the results showed that: With the prolonged hydrolysis time and increased E/S, thedegree of whey protein hydrolysis(WPHD) first increased and then tended to a constant value;With the increased temperature and increased initial pH of the solution, the WPHD firstincreased and then decreased; With the increased substrate concentration, the WPHDdecreased. The optimal conditions of enzymatic process: reaction temperature60℃, initial pH10.5, E/S0.06, hydrolysis time5h. The WPHD was32.60%. HPSEC showed that themolecular weight of whey peptide was300-6000Da.2. The influence of various factors on the production of whey protein peptide chelatingcalcium was studed, the results showed that: With the increased weight ratio of peptide andcalcium salt, increased initial pH and increased reaction temperature, calcium chelation ratefirst increased and then decreased; With the increased quality of calcium salts, the calciumcontent of the product first increased and then tended to a constant value; With the prolongedreaction time, calcium chelation rate first increased and then tended to a constant value. Theoptimum reaction process: the weight ratio of peptide and calcium salt1:5, the initial pH ofpolypeptide solution10.5, the reaction temperature65℃, the reaction time50min. Theproduct was water-soluble, the content of calcium was10.5%±0.5%, calcium chelation ratewas7.45%.After chelating reaction of whey protein peptide and calcium, functional group NH2-andCOO-infrared absorption peak shifted and the results indicted a linear relationship betweenthe wavelength and calcium content; UV scan spectra peaks around200nm violet shifted; Thecalcium ion mainly binded with NH2-in whey protein, but the calcium ion primarily chelated with COO-in reaction. XRD patterns showed two new peaks in32°and45°diffraction angle.3. The influence of various factors on the core embedded rate in peptide-calciummicrocapsules was studed, the results showed that: with the increased mass fraction of wallmaterial, increased solution concentration, higher inlet air temperature, quicker feed pumpand extended sonication time, the core embedded rate first increased and then decreased; Theoptimal production process: the mass fraction of wall material40%, ultrasonic time20min,inlet temperature of spray drying145℃, feed pump speed7r/min. The core embedded ratewas68.88%.The particle size of peptide-calcium microcapsule mainly located in2-10um, themicrocapsule was easily dispersed in acidic solution.4. The influence of of lecithin addition on the digestive performance of peptide-calciumwas studed, the results showed that: In simulated stomach digestion, peptide-calcium releaserate was not proportional to lecithin addition, but inversely proportional to the embedding rate;In simulated intestinal digestion, the absorption rate of peptide-calcium was proportional tothe embedded rate before100min, and proportional to lecithin addition after3h.The comparison results of in vitro digestion performance of various calciumsupplements showed that: The calcium release rate after1h in simulated stomach digestion:Caltrate> Osteoform calcium≈Laboratory peptide calcium> New Zealand microcapsulesmilk calcium> Laboratory microcapsules calcium. The calcium absorption rate after3h in thesimulated intestinal digestion: Laboratory microcapsules calcium> Laboratory peptidecalcium≈Osteoform calcium> New Zealand microcapsules≈Caltrate calcium milk calcium.