| The roe protein of Larimichthys crocea has poor solubility and emulsification.The preliminary study in the laboratory showed that after the enzymatic modification,the emulsifying performance of the protein with a hydrolysis degree of 4.6% was significantly improved,but it was also found that p H had a significant impact on the emulsification performance of the enzymolysis protein.In the neutral,the emulsification performance was excellent,while in the acid condition,its solubility was poor,flocculation was easy to occur,emulsification activity and emulsification stability declined sharply.In order to improve the stability of hydrolyzed protein in acid condition,different proportion of soybean lecithin was added,and then clarify its mechanism.On this basis,the best proportion of hydrolyzed protein-soybean lecithin was used as emulsifier to prepare the beta carotene emulsion with oil as carrier.The simulated digestion experiment in vitro was carried out to study its digestion mechanism in vivo,and the emulsion was applied to the preparation of acidic fruit flavored beverage containing beta carotene to investigate its stability.(1)Firstly,prepare emulsions with different ratios of hydrolyzed protein and soy lecithin(1: 0,0.8: 0.2,0.6: 0.4,0.5: 0.5,0.4: 0.6,0.2: 0.8,0: 1),studied the effect of soybean lecithin on the stability of hydrolyzedprotein by emulsify properties,physical stability and storage stability.The results showed that the emulsification performance of the emulsion stabilized with composite of hydrolyzed protein/soybean lecithin was significantly improved,compared with emulsions stabilized by hydrolyzed protein and soybean lecithin.When the ratios of hydrolyzed protein and soybean lecithin was 0.2:0.8,this composite demonstrated greatest emulsifying performance.The smallest particle size and the narrowest distribution of the oil droplets was found in the emulsion stabilized with this composite.During storage,In the emulsion added with soybean lecithin,the ratio of the emulsion has better oxidation resistance.(2)In order to study the action mechanism of hydrolyzed protein and soybean lecithin under acidic conditions,the combination mechanism was investigated by fluorescence titration and three-dimensional fluorescence spectroscopy.It’s found that: under p H = 4.0,the quenching method of hydrolyzed protein by soybean lecithin is static quenching,the interaction between soybean lecithin and hydrolyzed protein is hydrophobic;the complex of soybean lecithin results in the change of the microenvironment of Tyr and Trp in hydrolysate protein,and the extension of polypeptide chain and the change of conformation of hydrolysate protein.The maximum binding amount of hydrolysate protein-soybean lecithin is 0.77.(3)The nanoemulsion of β-carotene was prepared by hydrolyzed protein-soy lecithin with a ratio of 0.2: 0.8.The digestion and absorption process of the emulsion was studied by simulating in vitro digestion experiments.The results showed that in the process of simulated digestion,the particle size of the emulsion in the small intestine was smallest,and FFA of beta carotene reached 82.62%,It shows that digestion and absorption mainly occur in the small intestine stage,which can make β-carotene fully absorbed and utilized in human body.(4)Formulate acid drinks containing β-carotene,the best scheme ofβ-carotene containing acid beverage was selected by sensory evaluation.Then,the effects of four thickeners of xanthan gum,carrageenan,sodium carboxymethyl cellulose and sodium alginate on the stability ofβ-carotene-containing acid drinks were analyzed by LUMi Sizer.The results showed that when the sucrose content was 8% and the orange flavor added 0.17%,the taste of the beverage was the best.When xanthan gum was used and the amount of xanthan gum was 0.08%,the area of starting curve and ending curve was the smallest,and the instability index was the lowest,indicating that 0.08% xanthan gum can better maintain the stability of the system.(5)The stability of acidic fruit-flavored beverages decreases with increasing storage temperature.At the same time,the fruit-flavored beverages are more stable when the homogenizing pressure is 30 MPa. |
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