Study On Production Process Optimization Of Lycopene By Neurospora Crassis And Its Application In Antioxidant Preservation Of Food

Lycopene is a carotenoid that does not contain oxygen and has a high degree of conjugation,which gives it strong antioxidant activity.And lycopene has many physiological functions,such as anti-inflammatory and anti-tumor,protecting the cardiovascular and cerebrovascular system,enhancing immunity etc.It has good applications in food,cosmetics,health products and aquaculture.In lycopene production,microbial fermentation has attracted widespread attention.Among them,the nutritional requirements of Neurospora crassa are low,and lycopene can be synthesized through the MVA pathway without producing harmful metabolites,so this paper selected Neurospora crassa as the starting strain,by replacing nitrogen sources and exogenous addition of oleic acid,then optimizing its fermentation conditions,so as to increase the yield of lycopene,and optimize the extraction process by saponification to improve the extraction rate of lycopene.Finally,the antioxidant preservation of lycopene in food and its application in beef tallow were studied.1.Firstly,the effects of nitrogen sources and concentrations of peanut meal,rapeseed meal,soybean meal on lycopene production by Neurospora crassa were compared.It was found that replacing nitrogen source with 20g/L soybean meal had a better effect on the growth and production of lycopene.Exogenous oleic acid was added to promote lycopene synthesis and bacterial growth,and single factor experiments were carried out.Finally,the optimal fermentation conditions were determined by response surface optimization method:oleic acid addition concentration of 0.8g/L,oleic acid addition time of 69h,standing culture time of 125h,in this case,lycopene yield was4.18±0.15mg/L,1.87 times of the blank group.2.Lycopene of Neurospora crassa was extracted by saponification method,and the extraction conditions of saponification were optimized.First,the saponification agent and its concentration were screened.The results showed that 0.03mol/L Na₂CO₃was the best saponification agent.Determine the optimal saponification conditions through single factor experiments and response surface optimization method:saponification temperature 69℃,saponification time 16 minutes,bacteria volume to saponification agent ratio 1:37,the extraction amount of lycopene was 0.63±0.06mg/g,than the unsaponified group high 52.38%.3.By treating fresh cut potatoes,beef,and grass carp slices with lycopene,the changes of potato browning,color difference value and myoglobin ratio of beef,thiobarbituric acid value of grass carp slices during storage were determined respectively,and compared with the common antioxidant Vc,so as to evaluate the application of lycopene antioxidant in food preservation.The results showed that lycopene could significantly inhibit the browning degree of potato.It can effectively slow down the decrease of color a*value and the proportion of oxygenated myoglobin during beef storage,and slow down the increase of the proportion of high iron myoglobin.It can effectively delay the increase of thiobarbituric acid value during the storage of grass carp fillets.In addition,the effects of various indexes of lycopene treatment are better than Vc,indicating that lycopene has stronger antioxidant activity,can more effectively delay the oxidation and deterioration of various foods,and can be better applied in food preservation.4.The study on the application of lycopene to beef tallow was discussed.By preparing the beef tallow samples with different lycopene addition levels,as well as the beef tallow samples with common antioxidants Vc and BHT,then the peroxide value and acid value of each sample during storage were measured.Among them,when the addition of lycopene is 0.0015%,it can effectively inhibit the rise of peroxide value and acid value of beef tallow samples,indicating that lycopene can be used as a natural antioxidant in beef tallow,and can effectively prolong the shelf life of beef tallow.