Preparation, Activity And Structures Of Se-enriched Corn Protein Hydrolysates Facilitating Alcohol Metabolism

In order to utilize and develop the Se-enriched corns effectively, Se-enriched corns from Enshi were studied. The four kinds of Se-containing proteins, Se-polysaccharide, Se-nucleic acids were extracted from Se-enriched corns, and the selenium content of all components were determinated by HG-AFS. Se-enriched corn proteins were extracted by alcohol and NaOH solutions, and then were hydrolyzed by Alcalase. The facilitating alcohol metabolism activities of Se-enriched corn peptides, corn peptides and inorganic selenium were investigated by animal test in vivo. Furthermore the primary structures of Se-enriched corn peptides were analyzed by HPLC-MS/MS method couple with mass spectrum database. In addition, the qualitative and quantitative analysis of seleno-amino acids were identified by HPLC-ICP-MS method. The major results were as follow.1. Combined forms of Selenium in Se-enriched cornsThe Se-containing proteins are as the main storing form in the corns accounting for 87.40% of total selenium, the selenium content was 8.854 μ/g. Also part of selenium existed in polysaccharide and nucleic acids. There are 5.086 μg/g and 3.397 μg/g selenium in glutein and zein which are account for 57.44% and 38.37% respectively.2. Preparation and activity of the Se-enriched corn peptides facilitating alcohol metabolism(1) The optimal conditions of corn proteins extraction are as follow:the material to solvent ratio is 1:13 (w/v), the alkali (0.1mol/LNaOH) to ethanol (95%) ratio is 1:1 (v/v), the temperature is 45℃. The proteins content in extractive is 68.87% and the selenium content in proteins is as high as 9.03 μg/g,.(2) The optimal conditions of hydrolysis are as follow:the material to solvent ratio of 1:35 (w/v), the temperature of 60℃, the Alcalase dosage of 0.6%. Under these conditions, selenium recovery rate was as high as 81.78%, the peptide recovery was 73.32%, the degree of hydrolysis was 10.50% and the scavenging activity toward·OH with an IC50 value was 3.57 mg/ml.(3) The selenium-enriched corn peptides at the dose of 100,200 and 400 mg/kg could reduce 11.08%,30.33% and 50.99% of blood alcohol concentration (BAC) in mice those who consumed large amounts of alcohol, and BAC decreased very significantly (P<0.01) in a dose-dependent manner. The BAC was significantly reduced in selenium-enriched corn peptides group at the dose of 200 mg/kg (P<0.01) and 400 mg/kg (P<0.01) when compared to the corn peptides group at the dose of 200 mg/kg.(4) The BAC of corn peptides group and selenium-enriched corn peptides group which could reduce 31.40% of BAC had significant difference (P<0.01) under the same dose, and selenium-enriched corn peptides showed highly significant difference with Na2SeO3 (P<0.01). The BAC was sgnificantly reduced in selenium-enriched corn peptides group (P<0.01) when compared to the corn peptides+Na2SeO3 group under the same dose.3. Structure identification of seleno-peptides and seleno-amino acids in Se-enriched corn protein hydrolysate(1) Six kinds of seleno-peptides were identified as SeMet-MeSeCys-E, SeMet-A-A-K, Met-MeSeCys-E, MeSeCys-E-D, I-MeSeCys-E, y-Glu-MeSeCys. Five of them contained MeSeCys and Glu(E), and two of them had SeMet. SeMet-A-A-K was seleno-peptides facilitating alcohol metabolism.(2) Seleno-amino acids and dipeptide had also been quantified with the standard samples, the reducing order of content was SeMet, SeEt, y-Glu-MeSeCys, MeSeCys and SeCys2.(3) Four kinds of corn peptides were identified as Y-Q-Q-P-I-I-G-G-A, L-Q-L-Q-Q-L-L-P, Q-Q-I-L-L-P-F, L-P-F-Y-L. These peptides contained hydrophobic amino acids (L, I, P, F, Y), especially L, whith could play an important role in antioxidant and facilitating alcohol metabolism activities.