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Maillard reactions is the reducing sugar and the amino compound (mainly amino acids, lower peptides, proteins, etc.) occurs between the non-enzymatic reaction, is widespread in the food, feed storage and processing in a non-enzymatic browning (Nonenzymic browning) reaction. Maillard reaction products in food processing and storage process itself produces a class of substances can be considered natural, Maillard reaction products of the antioxidant activity of today's food industry will become a hot research topic. L - ascorbic acid is the human life course a key and indispensable substances in the animal and plant life activities also play an important role and widespread. This paper, based on the amino acid L-ascorbic acid model system to explore the Maillard reaction occurs after the determination of L-ascorbic acid method; Maillard reaction products with UV absorbance (A294) and browning intensity (A420) as an indicator for the process as well as the Maillard reaction UV absorbance and browning intensity and antioxidant activity relationships were discussed; and reducing power, DPPH radical scavenging capacity as an indicator of their different conditions and different segments of the Maillard reaction product of molecular weight antioxidant activity were analyzed to evaluate and compared. The main contents and results are as follows: 1, L-ascorbic acid and amino acid model system explored the Maillard reaction occurs after the determination of L-ascorbic acid method. With metaphosphoric acid solution as extractant, using second derivative spectra were determined Maillard reaction products of L-ascorbic acid content. The linear range of 1.00 ~ 12.00μg/mL, regression equation C = 6721.304A-0.0588, the linear correlation coefficient γ = 0.9999, recoveries 96.50% ~ 103.75%. The method is simple, interference, suitable for use in the Maillard reaction occurs after the system L-ascorbic acid content; 2, in the L-ascorbic acid and amino acid pattern of the system of pH on the six kinds of amino acids (L-lysine, L-methionine, L-alanine, L-proline, L-arginine, L-cysteine) Maillard reaction products of antioxidant activity, and its optimum pH conditions in the under reducing power and DPPH radical scavenging capacity were compared. The results showed that: L-lysine, L-methionine, L-alanine, L-proline The UV absorbance of the Maillard reaction product, browning intensity, reducing power, DPPH radical scavenging ability at pH = 5.0 reaches the maximum; L-arginine Maillard reaction product the maximum pH = 4.0; L-cysteine ??Maillard reaction product reaches the maximum pH = 8.0. Fe2 chelating capacity as the pH increases, and the reducing power of the Maillard reaction product is closely related with the UV absorbance. Six kinds of amino acids through the Maillard reaction product comparison found antioxidant activity, L-methionine and L-lysine than the other four amino acids of the Maillard reaction product stronger antioxidant activity; 3, in the L-ascorbic acid and L-methionine / L-lysine model systems studied the Maillard reaction products of reaction time on the antioxidant activity. The results show that: In the L-ascorbic acid and L-methionine / L-lysine Maillard reaction product model systems UV absorbance, browning intensity was 200 min and 120 min former increased dramatically; reducing power, DPPH radical scavenging reaction time respectively for 120 min 200 min and the maximum; 4, the L-ascorbic acid and L-methionine / L-lysine model system is studied reactant molar ratio of the amount of the Maillard reaction The antioxidant activity of the product effect. The results showed that: the L-ascorbic acid and L-methionine model system / L-lysine model system in the UV absorbance of the product Maillard browning intensity, reducing power, DPPH radical scavenging ratio of the amount of the substance ( L-methionine / L-lysine and L-ascorbic acid molar ratio) were 1:5,1:3 reaches the maximum; 5, the L-ascorbic acid and L-methionine / L-lysine was studied model system in the Maillard reaction products with different molecular weights above antioxidant activity. Segments with different molecular weights obtained by ultrafiltration (0.5-1kDa, 1-3kDa ,3-5kDa ,5-10kDa ,10-30kDa, gt; 30kDa) The Maillard reaction products, and the different sections of the Maillard reaction product of molecular weight antioxidant activity L-ascorbic acid and antioxidant activity of the contrast and the molecular weight of each segment of the infrared spectrum of the product. The results showed that: the L-ascorbic acid and L-methionine / L-lysine model system, the different molecular weight antioxidant activity segment is a clear difference, wherein the molecular weight gt; 30kDa of Maillard reaction products reducing power, DPPH radical scavenging capacity max. But all product segments molecular weight reducing power, DPPH radical scavenging ability is weaker than the L-ascorbic acid. Seen by infrared spectroscopy, infrared spectroscopy found that Maillard reaction products of the two systems may contain COC, C-OH-,-OH, CH, CO, C = N, C = C, NH,-OH, and NH2C = O other functional groups. This thesis helps people to L-ascorbic acid antioxidant activity Maillard reaction product understanding as to find new anti-oxidants and the L-ascorbic acid Maillard reaction products of antioxidant activity in the future course of food processing and storage to be more good use for reference.
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