Analysis Of Browning Products Of Fresh Wet Noodles

Fresh wet noodles are loved by consumers because of their refreshing taste,healthy nutrition,and other characteristics,but they have a short shelf life and are prone to deterioration at room temperature.Usually,people can only buy it right away and cannot store it for a long time.The problem of browning has always been the technical bottleneck for the preservation of fresh wet noodles.Research of the browning products of fresh wet noodles and analysis of the component structure will help people to understand the browning mechanism and help people to explore methods for inhibiting the browning of fresh wet noodles,and it is of great significance to realize the industrialization of fresh wet noodles.In this paper,browning fresh wet noodles were used as raw materials,the extraction parameters are optimized,the separation and purification methods were explored,and the raw wheat flour is used as a control,the components produced by browning were selected for separation and preparation,and the structure of the obtained monomer compounds was analyzed.The main research contents and results are as follows:(1)Response surface methodology was used to optimize the extraction of browning products from fresh wet noodles.The fresh wet noodles after browning were used as raw material,the effects of ethanol volume fraction,solid-liquid ratio and extraction time on the extraction of browning products were investigated by single factor experiment.The optimal extraction parameters were obtained by response surface methodology as follows: volume fraction 70%,solid-liquid ratio 1:9.5(g : m L)and extraction time 11 d.Among them,extraction time had the most significant on the extraction effect of browning products,followed by ethanol volume fraction,and the ratio of solid to liquid was the smallest;under this condition,the average platinum-cobalt index of browning products was 376.66,which was close to the predicted value,indicating the reliability of the prediction model,and the best extraction scheme of browning products from fresh wet noodles was obtained(2)Study of the purification process of the crude extract of browning products.The browning product extract contains a large amount of protein and carbohydrate compounds,which greatly hinders the separation of browning product components.It was planned to use the Sevag method combined with the dialysis method for deproteinization,and then macroporous resin adsorption method was used to remove carbohydrate compounds.The effects of Sevag deproteinization times,dialysis times,loading concentration,loading flow rate,loading amount,desorbent concentration,desorption flow rate and desorbent dosage of macroporous resin column on impurity were investigated.The best purification process parameters were obtained as follows: Sevag method was used to remove protein for 7 times,dialysis for 6 times,AB-8 macroporous resin was used,the platinum-cobalt index of sample solution was 88,sample flow rate was 3 m L/min,sample volume was 5 BV,80% ethanol solution was desorbed,desorption flow rate was 3 m L/min,and the amount of desorbent was5 BV,which can remove 98.60% of protein and 69.56% of carbohydrate in the crude extract of browning products,has a significant purification effect.After the purification operation,the yield of the crude extract of the fresh wet noodle browning product was 0.05%.(3)Isolation and,purification of the monomeric compounds of browning products.The crude extract of the browning product after removing impurities was separated using a C18 chromatography column,and the components C1,C2,and C3 were obtained by gradient elution with different concentrations of methanol solution.The raw wheat flour was used as a blank control,and the same extraction and purification parameters were used.The original colored matter extracts in the flour were prepared and,detected by high performance liquid chromatography,and the browning products were screened out.Since component C1 contained more types of browning products,and these browning compounds can be separated with high efficiency.C1 was separated and prepared by high performance liquid chromatography.Finally 4 monomer compounds(C1-1,C1-2,C1-3 and C1-4)were obtained,and the purity of each component was detected by high performance liquid chromatography.The purity of each component was 84.52%,90.14%,97.83% and 98.69%,respectively,and the mass of each compound was 2.8 mg,2.1 mg,6.6 mg and 3.3 mg.(4)Structure analysis of browning product C1-3.The purity of compound C1-3 is more than95%,and its mass is more than 5 mg,which meets the structural identification conditions.Therefore,fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance spectroscopy(NMR)and mass spectrometry(MS)were used to analyze the molecule structure of C1-3 compound.The results showed the browning product C1-3 compound was 2-hydroxyindole-3-propylamine.