Research On Alternatives Of Sulfite In Browning Inhibition Under Alkaline Conditions

Non-enzymatic browning is a generic term for a group of very complex reactions in food chemistry,it mainly refers to a series of reactions that without the action of enzymes,sugars condense or degrade themselves with other compounds under heat and undergo a series of complicated reactions to generate large amounts of black substances and volatile substances.Non-enzymatic browning includes Maillard browning,ascorbic acid browning,and caramelization reactions,in which Maillard reaction is the most common non-enzymatic browning reaction because it is widely present in the processing of various foods.Since the Maillard reaction is very common in the thermal processing of foods and produces undesirable brown substances,using additives to inhibit browning is one of most common practices.As an efficient browning inhibitor,sulfite is used in various processes,but its safety has been questioned in recent years,so it is necessary to seek its safe alternative.Many scholars have already tried many alternatives of sulfites in their researches.However,the reaction conditions and observational parameters of various studies are not the same,it's very hard to reflect the differences between the various additives.Moreover,most actual food system is acidic,but the extraction of plant polysaccharides is mainly at weakly alkaline or neutral condition,so the reaction mechanism is different.This paper builds a number of model reaction systems includding glucose/lysine,maltose/lysine and L-ascorbic acid/lysine,and uses A420,UV absorbance,L*,a*,b*,?E and C*as specific indicators to compare the effects and efficiencies of several common non-sulfur browning inhibitors on non-enzymatic browning under alkaline conditions.The test results of the paper are as follows:1.In the glucose/lysine system under alkaline conditions,L-cysteine,thiamine shows a strong browning inhibition ability,The L-cysteine half-inhibitory concentration was 17.10 mmol/L,the thiamine half-inhibitory concentration was 74.42 mmol/L,and the sodium sulfite half-inhibitory concentration was 116.89 mmol/L.,both of their inhibition ability is better than sodium sulfitez.2.In the maltose/lysine system under alkaline conditions,L-cysteine and thiamine still have strong browning inhibitory capacity.CaCl2 also has a certain ability to inhibit browning.The half-suppression concentration of L-cysteine was 36.58 mmol/L,the half-suppression concentration of thiamine was 112.70 mmol/L,the half-suppression concentration of sodium sulfite was 102.88 mmol/L,CaCl2 failed to reduce browning index to half that of the blank control group.Inhibition ability of L-cysteine is better than sodium sulfite,but inhibit browning effect of thiamine and CaCl2 is not as good as sodium sulfite3.In the L-ascorbic acid/lysine system under alkaline conditions,L-cysteine and CaCl2 still have the ability to inhibit browning.The half-suppression concentration of L-cysteine was 16.68 mmol/L,the half-suppression concentration of sodium sulfite was 36.17 mmol/L,CaCl2 failed to reduce browning index to half that of the blank control group.L-cysteine is more effective than sodium sulfite,while CaCl2 is less effective than Sulfite4.Under alkaline conditions maltose/lysine system,response surface methodology was used to study the complex use of L-cysteine,thiamine and CaCl2.The results showed that when the L-cysteine concentration was 75 mmol/L,the thiamine concentration was 125 mmol/L,and the CaCl2 concentration was 25 mmol/L,the best inhibitory effect was obtained,browning index was reduced from 1.787 to 0.612.However,the effect of inhibitory was not as good as 125 mmol/L L-cysteine along.