Study On Yellow Pigment Produced By Liquid Fermentation Of Monascus And Product Development

Monascus as a traditional Chinese food fermentation bacteria is currently the only important microorganism that can be used to produce edible pigments.Monascus pigment is a polyketide secondary metabolite produced by Monascus.It can be divided into red,orange and yellow pigments according to color.Monascus yellow pigment has bright color and strong biological activity.At present,the liquid fermentation production of monascus yellow pigment is still at the laboratory level,so research and development of monascus yellow pigment has great prospects.Aiming at the problem of low liquid fermentation yield,a new method for producing yellow pigment from liquid fermentation potatoes of Monascus was designed.This process improved the yield of yellow pigment from Monascus C100 by controlling fermentation conditions and improving fermentation methods.It also reduced the yield of citrinin.In this paper,orthogonal test and response surface test were used to obtain the optimal ratio of Monascus seed liquid and the optimal process parameters of yellow pigment produced by Monascus liquid fermentation potatoes.The optimal ratio of Monascus seed liquid was 5%glucose and 0.83%soybean meal.The optimal process parameters for producing yellow pigment from Monascus liquid fermented potatoes were 100 mL of liquid loading,40 mL of inoculation,7 days of fermentation time,and 180 r/min of the shaker.Monascus seed liquid was inoculated into potato homogenate treated with 0.06%α-amylase and 0.4%saccharifying enzyme for liquid fermentation.The ratio of potato to water was 1:5(g:mL).The enzyme treatment time is 120min,and the treatment temperature is 65-75℃ The type of nitrogen source,high initial glucose concentration and low initial pH in this process method have an impact on the yield of yellow pigment and are more conducive to the synthesis of yellow pigment.The maximum color value of intracellular yellow pigment was 341.2 U/g,which was 58.73%higher than that of conventional liquid fermentation;the color value of extracellular yellow pigment was 168 U/g,which was 38.39%higher than that of conventional liquid fermentation.Using liquid chromatography-mass spectrometry to identify that the intracellular yellow pigments produced by this method are mainly monascus and anka monastoxanthin,the yield of these two pigments increased by 33.91%and 84.32%,and the concentrations were 274.6 μg/mL and 167.1 μg/mL.A mycotoxin-citrinin is accompanied by the production of monascus pigment.The content of citrinin produced by the new process in this paper is 97.85%lower than that of the original Monascus C100 strain,which effectively reduces citrinin.The fermentation broth obtained by the process described in this paper was detected by a stability analyzer and found that the migration of particles was slow and stable,and the phase thickness was stable,indicating that the overall stability of the fermentation broth was good.The electronic nose analysis of the fermentation broth indicated that the flavor substances were mainly alcohols and aldehydes and ketones.The fermentation broth has good antioxidant activity,and the reducing power is equivalent to the reducing power of VC of 350 μg/mL.The maximum DPPH free radical scavenging rate is 69.81%,the IC50 value of the superoxide anion radical scavenging rate is 0.873mL,and the ABTS free radicals the maximum clearance is equivalent to 0.0035 mg/mL of VC,and the maximum clearance of hydroxyl radicals is 87.95%.At the end of this paper,a kind of Monascus potato fermentation biscuit was developed by using the fermentation liquid and fermentation products obtained by this process.The biscuit has high nutritional value and is easier to digest.It not only increases the diversity of the taste of the biscuit,but also improves the added value of the potato to a certain extent.