Effect Of Maillard Reaction Productions On Sesame Oil Oxidation Stablity

Maillard reaction products(MRPs)with strong antioxidant activity are generated from the process of food processing and storage.The dominate theory statements that MRPs originated from roasting process of reducing sugars and amino acids in sesame seed enhance the oxidative stability of sesame oil while the oxidation mechanism of MRPs was not shown presently.This thesis forces on the relationship among variation of reducing sugars and amino acids,MRPs and oxidative stability of sesame oil,MRPs prepared from simulation Maillard reaction were added into sesame oil and lard,the effects of oxidative stability of MRPs were studied.(1)Effects on qualities of sesame oil and primary components of sesame were studied in the process of roasting.Color of sesame oil increases gradually in the process of roasting and changes from luminous yellow to reddish brown,acid value and fatty acid composition are not change significantly of all samples;peroxide value of sesame oil presents increasing first and then decreasing while the oxidation stability increasing directly in roasting;change in type and content of flavor.We find that serine,cysteine,arginine,lysine and fructose,xylose,glucose act as precursors of Maillard reaction through the researching on the changes in amino acids and reducing sugar in sesame squeeze.(2)We find that sesamol,only 13 mg/100 g in the roasted and unroasted sesame oil,was not the dominant factor which resulting in the high oxidation stability of the roasted sesame oil through the researching on the different antioxidant contents in the roasted and unroasted sesame oil as well as the promoting ability of pure sesamol on the oxidation stability of the unroasted sesame oil.The research shows MRPs were positively correlated with oxidative stability of sesame oil by correlation analysis,it refers that MRPs is the dominate factor enhance oxidant stability of roasted sesame oil.(3)We find that arginine,lysine and reducing sugars have undergone Maillard reaction to form intermediates and brown substances by measuring the contents of the amino acids and reducing sugar in each reaction system,carbonyl prefer connect with thiol than amino in cysteine system and serine mainly take place thermal degradation and Strecker degradation in serine system.The free radical scavenging of products of arginine and lysine system increase gradually and positive correlated with degree of browning.According to the change of reducing sugar,amino acid and free radical scavenging ability in the reaction system,it is refers that arginine,serine,lysine and cysteine are the most depleted during roasting,while lysine and arginine may be the dominant factors which resulting in the high oxidation stability and deep color of the roasted sesame oil.(4)It refers from single factor experiment and orthogonal experiment that the optimum technological condition of glucose-protein is 130?,180 min,pH 6.5 and sugar-protein ratio is 6;The optimum technological condition of fructose-protein is 130?,120 min,pH 6.5 and sugar-protein ratio is 10;The optimum technological condition of xylose-protein is 130?,180 min,pH 6.5 and sugar-protein ratio is 10;DPPH radical scavenging capacity and reducing capacity of the three Maillard reaction products under the optimal condition are improved at a certain extent,and the antioxidant activity of xylose-protein Maillard reaction products is strongest.(5)The effect of MRPs on oxidation stability of cold-pressed sesame oil was studied by Schaal oven experiment and acid value,peroxide value and anisidine value were measured.The results suggest that MRPs inhibit the generate process of hydroperoxide in cold-pressed sesame oil and resist oxidation capacity positive correlate to content of MRPs.When MRPs added into sesame oil and content reach 2%,the antioxidant of sesame oil perform best,after 20 days of accelerated oxidation,peroxide value and anisidine value decrease 58.3% and 31.8% comparing with control sample,respectively.Compared with added into cold-press oil,MRPs in lard system shows lower antioxidant activity;Correlation analysis shows that MRPs shows synergistic effect with sesamol and tocopherol,synergistic effect between MRPs and tocopherol is superior to sesamol.It refers that the primary factor induces oxidation stability of hot-pressed sesame oil is synergistic effect among MRPs,tocopherol and sesamol.