Preparation Of Pea Peptide Maillard Reaction Intermediates With Salt Reduction And Umami Enhancement And Their Controlled Formation Of Process Flavors

Salt and monosodium glutamate are essential salty and umami seasonings in daily life.However,excessive use can lead to excessive sodium intake,which will endanger human health.Therefore,it is necessary to seek effective substitutes for salt and monosodium glutamate.Pea protein isolate,as a kind of low allergenicity vegetable protein,has a lot of flavor amino acids and flavor peptides in their enzymatic hydrolysates.As a result,enzymatic hydrolysates of pea protein isolate can be used as a condimentin with salt reduction and umami enhancement in food products.Enzymatic hydrolysates of pea protein isolate with different enzymatic hydrolysis degrees were prepared by the controllable enzymolysis technology in this study.The results of electronic tongue and sensory evaluation indicated that the enzymatic hydrolysates in salt solutions had an obvious effect of increasing salt and umami.The stable pea peptides Maillard reaction intermediates(MRIs)were further prepared.The taste traits,anti-oxidation properties and flavor characteristic traits in the thermal processing of MRIs were studied to develop a new type of flavor enhancer.For the preparation of enzymatic hydrolysis products with high Maillard reaction activity,the enzymolysis technology of pea protein isolate was optimized based on the degree of hydrolysis and solids dissolution rate.The optimum technological parameters were as follows:substrate concentration was 10%(w/w),protamex?was at 3500 U/g addition level,hydrolyzed at 60?for 4 h,and aminopeptidase was at 400 U/g addition level,hydrolyzed at 50?for 4 h.Under this enzymatic condition,96.42%of the enzymatic hydrolysates were substances with relative molecular mass less than 1000,and free amino acids only accounted for 9.65%of total amino acids.This suggested the main components of the enzymatic hydrolysates were small molecular peptides,which were suitable for preparing pea peptides MRIs.The pea peptides MRIs was prepared through using the above enzymatic hydrolysates of pea protein isolate as raw materials.With Cysteine as tracers,the variable-temperature Maillard reaction was used to determine the critical formation time of MRIs at 80°C.The formation time were respectively as follows:for ribose,heating for 40 min;for xylose,arabinose(Ara),fructose,glucose,and galactose,heating for 60 min.Then the corresponding pea peptides MRIs were prepared in the aqueous solutions.Electronic tongue and sensory evaluation were used to analyze the taste traits of pea protein hydrolysates and their MRIs in dilute salt solutions.Both evaluations showed that bitterness of enzymatic hydrolysates of pea protein isolate reduced through Maillard reaction and the umami-enhancing ability of MRIs was higher than enzymatic hydrolysates.Amomg all pea peptides MRIs,the Ara-pea peptides MRIs showed the most superiority for salt reduction,umami improvement and bitterness reduction in the salt solutions.The intensities of umami and saltiness were positively correlated with the concentration of Ara-pea peptides MRIs(1 mg/g?6 mg/g)in salt solutions.Even when the dosage of MRIs was 1 mg/g in salt solutions,it could achieve a 20%reduction in Na Cl content without decreasing saltiness;when the dosage of MRIs was 4 mg/g in salt solutions,the umami was significantly higher than that of 6 mg/g MSG in salt solutions,which could be great potential substitutes for salt reduction and umami improvement.On the other hand,the increased Ara-pea peptides MRIs promoted aldosterone secretion in saliva,which might enhance human perception of saltiness.The MRIs can derive fresh flavor in the subsequent Maillard reaction,so the flavor change law of Ara-pea peptides MRIs was researched during the heat treatment.The results demonstrated that Ara-pea peptides MRIs generated the most types and amounts of aromatic compounds after heating at 120°C for 2 h.Compared with unheated MRIs,the type of aromatic compounds increased by 9 and the content increased by 452.98%.After the thermal reaction,the bitterness significantly became lower,but the capacity of increasing saltiness and umami weakened.Giving a comprehensive account of aroma-forming ability and taste law of MRIs during thermal processing,hot pot was chosen as the application system to study the flavor enhancement law of Ara-pea peptides MRIs during 100°C boiling.The result showed that the addition of MRIs could enhance the aroma characteristics of the hot pot and still had the salt-increasing effect.The salt-increasing ability could reach 92.26%of that before thermal reaction.The in vitro antioxidant activity of Ara-pea peptides MRIs was further studied,and compared with Ara-pea peptides Maillard reaction products(MRPs)and enzymatic hydrolysates of pea protein isolate.DPPH free radical scavenging ability,reducing ability and Fe²⁺chelating ability of MRIs were higer than enzymatic hydrolysates.When the dosage of MRIs was 3.0 mg/m L,reducing ability of MRIs was about 4.4 times that of the enzymatic hydrolysate.DPPH free radical scavenging ability of MRIs was lower than that of MRPs,reducing ability was equal to that of MRPs,but Fe²⁺chelating ability was higher than that of MRPs.When the dosage of MRIs was 6.0 mg/m L,Fe²⁺chelation rate of MRIs could reach 96.64%.