Nutritional Composition and Structural Analysis of Yeast Proteins Obtained by Fermentation with Different Strains
In order to analyze the differences in nutritional composition and structure of yeast proteins YP-1,YP-2,YP-3,YP-4 and YP-5,which were obtained by fermentation with 5 different yeast strains,and their nutritional composition and hydrolyzed amino acid contents were determined.The free polypeptide of yeast proteins was determined by high performance liquid chromatography-mass spectrometry.In addition,the structure of the yeast proteins was characterized by scanning electron microscopy,the particle size of the yeast proteins in solution was determined by laser diffraction particle size analyzer,and the secondary structure of the yeast protein was determined by Fourier transform infrared spectroscopy.The results showed that YP-5 contains the highest total mineral content,and the content of each yeast protein varies.The highest vitamin B2 content measured in YP-2 was 0.240 mg/100 g.The total content of vitamin PP in YP-3 and YP-4 was not much different.The ratios of EAA(essential amino acids)/TAA(total amino acids)of the five yeast proteins were all above 0.44,and the ratios of EAA/NEAA(Non-essential amino acids)were all above 0.79,which proved that yeast protein is an ideal protein source.The sequence determination of yeast protein free polypeptide showed that the expression of polypeptide was different among all groups.Scanning electron microscope results showed that the yeast protein was aggregated,and the particle diameters were 2.20-4.01 μm.The results of laser diffraction particle size analyzer showed that the average particle size of yeast protein solution particles was between 3-5 μm.Among them,YP-4 had the largest average particle size.In addition,secondary structures showed that the amide I bands of the five yeast proteins were concentrated at about 1724 cm-1.These results can provide theoretical guidance for the development of functional products of yeast proteins.
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维普
