Preparation Of A Novel Umami Flavoring By Enzymatic Hydrolyzing Of Corn Protein

Umami flavoring,also known as flavor enhancer,is a class of substances that can increase the flavor of food.Compared to MSG,umami peptide flavoring has not only mild and harmonious flavor but also high nutritional value,so its development is highly valuable.In this paper,the umami mechanism of peptide in the traditional chicken soup was studied,and peptide umami flavoring was prepared by plant protein hydrolyzing according to umami mechanism of chicken soup peptide.Corn protein was investigated to produce peptide umami flavoring by enzymatic hydrolyzation,the enzymatic hydrolyzing technology was optimized and the constitutents,peptide structures were analyzed.The white feather chicken was stewed and the chicken soup was obtained.After microfiltration and ultrafiltration,peptides<3 kD was analyzed with high performance liquid Chromatography-Mass Spectrum(HPLC-MS),1635 peptide sequences were obtained.By blasting these peptide sequence with Uniprot database,the peptides were found to be generated from certain regions in the original protein while more large the exposed rigion by solvent digestibility analysis,more peptides generated.The region is rich of sweet amino acids and hydrophilic amino acids.The amino acids in peptide cleavage site were predominanlyt hydrophilic amino acids.The cheap,high protein content and large yield corn protein was used as raw material for umami peptide preparation.Pretreatment was needed to break the compact structure of corn protein for its better enzymatic hydrolysis.The single variable factor pretreatment including acid treatment,cellulase pretreatment and ethanol extraction was conducted and cellulase pretreatment was proved to be most effective.The enzymatic hydrolysis process for corn protein was optimized: enzyme composition: Alcalase:Flavourzyme=1:1;enzyme:substrate(refered to protein)=5%;substrate concentration(w/v)=20%;temperature=50?;pH=8.0;time=21 h.The free amino acid and total amino acid composition,as well as peptide sequences of corn protein hydrolysates were analyzed,and it was found that the proportion of essential amino acids in the free amino acids was higher showing its high nutritional value.But the lack of essential amino acids in the lysine,nutrition is not comprehensive.The peptides had high ratio of sweet and umami amino acids and low of hydrophobic amino acids.The corn protein hydrolysates have the potential to be used for umami peptide flavoring preparation.