Preparation Of Pea Protein Maillard Peptides And Their Flavor Characteristics

As the most basic condiment in life,salt has the function of imparting saltiness and regulating flavor.However,due to the influence of cooking habits and food processing,the salt intake of people far exceeds the recommended value in dietary guidelines.As people pay more and more attention to health problems,it is urgent to develop salt reduction products.Maillard reaction products can not only enhance saltiness,umami and kokumi taste,but also bring characteristic aroma to food and improve antioxidant activity.In this research,pea peptides were used as substrates to construct a complex Maillard reaction system.The effects of reaction parameters on the color,flavor quality and antioxidant capacity were investigated.The preparation technology of thermal processing flavor peptides with the effect of salt reduction was established,and the mechanism of saltiness strengthening was explored.This research provided a new idea and theoretical reference for the development of scientific salt reduction products.The main research contents are as follows:In this paper,pea protein was hydrolyzed by proteases.Taking the degree of hydrolysis(DH)and solid dissolution rate as indexes,the optimal preparation process of pea protein peptides was determined as follows:when the substrate concentration was 8%(w/w),3500U/g substrate protamex protease?was added and hydrolyzed for 4 h,and then 400 U/g substrate aminopeptidase was added and hydrolyzed for 4 h.Under this condition of enzymatic hydrolysis,the DH reached 17.48%and the solid dissolution rate reached 71.99%.The chemical composition results showed that the hydrolysates were composed of 18.86%components with relative molecular weight<250,72.74%components with relative molecular weight 250?1000,and 8.4%components with relative molecular weight>1000.Moreover,the content of peptide-bound amino acids accounted for 90.83%of total amino acids,indicating that pea protein was mainly hydrolyzed into small peptides.Small peptides had higher reactivity and were suitable for Maillard reaction.The saltiness enhancement effects of Maillard peptides(MPs)derived from different reducing sugars were compared.The optimal reducing sugar was glucose.Taking browning degree,aroma and taste as indexes,the effects of Maillard reaction parameters on the quality of products were investigated.The preparation parameters of MPs with overall taste and flavor enhancement were determined as follows:the p H of solution was adjusted to 8.4 and reacted at 110?for 2 h.The MPs obtained under this condition had prominent saltiness enhancement effect,obvious umami and kokumi,low bitterness and light color.And the aroma of this product was harmonious,with meat and burnt aroma.In addition,linear regression analysis was used to analyze the correlation between electronic tongue and sensory evaluation.The results showed that the fitting effect of these two methods was good,which indicated that the electronic tongue,as a new taste evaluation method was reasonable and reliable in the analysis of saltiness,and can be used for rapid quantitative analysis of saltiness.In order to further analyze the influence mechanism of thermal reaction conditions on the saltiness enhancement effect of MPs,the products were analyzed from two aspects of chemical composition and saltiness sensitivity.Based on the results of relative molecular weight and amino acids,it was speculated that the taste characteristics of products were related to the degree of reaction,and the changes of small tasty peptides in the Maillard reaction process may cause the different taste of products.According to the analysis of aldosterone content in human saliva,the pea peptides and their MPs could both stimulate the secretion of aldosterone in oral cavity,indirectly promoted the increase of amiloride-sensitive cells,and strengthened the saltiness sensitivity of human body,resulting in a stronger saltiness feeling.Taking reducing power,DPPH radical scavenging capacity and Fe²⁺chelating capacity as indexes,the effects of Maillard reaction on antioxidant properties were investigated.When the same reducing power and DPPH radical scavenging efficiency were achieved,the concentrations of pea peptides were 15 mg/mL and 30 mg/mL,respectively,while MPs only needed 0.8 mg/mL and 1.0 mg/mL,respectively.At the same 10 mg/mL concentration,the Fe²⁺chelation rate of pea peptides was only 12.54%,and the Fe²⁺chelation rate of MPs was as high as 75.69%.Therefore,Maillard reaction could significantly improve the antioxidant activity.Because of the high reducing power of MPs,if added to iodized flavor salt,it may react with potassium iodate to form iodine and cause sublimation loss.Therefore,MPs are more suitable for flavor salt without iodization.