The Development Of Perilla Protein Products;the Development Of Perilla Protein Products

The content of protein in perilla seed is 20%～23%.The amino acid composition of perilla protein is more reasonable.It contains eighteen amino acid ,eight of which are essential amino acid to human. Besides the content of sulfur-containing amino acid (methionine + cystine) is lower,the composition of other amino acid is similar to that of popular oil plants protein.Perilla meal as by-product of perilla seed by extracting oil is processed into feed.The perilla protein is not well developed.The programe aims at the development of perilla protein resource ,to enhance the economic value of perilla.The preparation of perilla protein isolates (PPI) and perilla peptides was studied in this paper.The main results of study were as follows:1. perilla protein isolates was prepared from defatted perilla meal through alkali-extraction and acid-precipitation . The extration process was optimized by single factor and orthogonal experiments ,and the optimum process conditions were obtained as follows : alkali-extraction temperature 55℃,solid-liquid ratio 1:10, alkali-extraction pH 10, 2 times and 60min once , acid-precipitation pH 4.4.Under these conditions,the product yield was 24.5% ,and the protein content was 91.52%( N×6.25,dry).2. The function properties of perilla protein isolates were studied with soybean protein isolates (SPI) used as a standard reference .The Nitrogen Solubility Index (NSI) of the PPI had a similar trend to that of SPI within pH range from 2 to 12, but the PPI shown much higher solubility than that of SPI at isoelectric point. The PPI's capabilities of holding water,foaming,emulsification,gelatinaion and stability of foarms were lower than corresponding properties of SPI at pH 7.0. However, the oil adsorption capability of PPI was very close to that of SPI, and the emulsion stability of PPI was almost equal to that of SPI when the protein concerntration was higher than 3%. The results suggested that the PPI is a potential protein enhancer for food processing.3. the defatted Perilla Meal, the raw material, was hydrolyzed by Alcalase alkaline protease to make perilla peptides.Through the single factor experiment and orthogonal experiment,the optimum conditions for hydrolysis were confirmed as follows : concentration of substrate3%,pH9.5,temperature60℃, the amount of enzyme7%(E/S),time4h. Under optimum conditions, the degree of hydrolysis (DH%) was 38.75%,and the recovery rate of nitrogen is 87.62%.Then perilla protein hydrolyzates is decoorizated.The optimum process conditions for decolorization were as follows:the amount of active carbon 5.0%,pH3,temperature 60℃,time 40min. We get the ultimate product by freeze-drying perilla protein peptides. In the product ,the content of protein and peptides were of 68.4%( N×6.25,dry)and 65.1%( N×6.25,dry) respectively,and the component with relative molecular weight under 1000 was of 86.6%.4. The desalting technology of perilla peptides by DA201-C macroporous adsorption resin was studied.The results indicated that the optimum condition for desalting was obtained as follows : concentration of loading sample 20mg/ml, flow rate ofsampling 1BV/h,flow rate of water washing 2BV/h,and desorption rate of 70% ethanol 1.5BV/h.Under these conditions ,the ash content in perilla peptides was decreased from 20.6%to 0.93%,and the content of peptides was incresed from 65.1 % ( N×6.25,dry)to 85.1%( N×6.25,dry).