| Red pepper,known as sweet pepper,is the genus Solanaceae pepper fruit,which rich in vitamin C.In general,the method of eating pepper is fried or pickled.In China,the traditional pickled pepper processing technology is usually using natural pickled,which is to add salt and other condiments pickled.The storage period of pickled pepper is 30 days when preserved at low temperature,with accompanied by lactic acid fermentation.People usually using high-temperature sterilization instantaneous to extend storage period,but this method is easy to cause the nutrients lossed and sensory quality decreased.Therefore,breaking the traditional methods of sterilization,to explore new ways and principles of sterilization is a new topic of pickled red pepper research.This experiment is based on the non-thermal effect principle of ultrahigh pressure sterilization,which was carried out by using ultrahigh pressure treatment of pickled red pepper with different pressure and packing time.The experimental temperature was controlled at 25 ?,to exclude the thermal effect.Pickled pepper were placed in a cold storage at 4? and 25? in the incubator,regular sampling,the effects of different ultrahigh pressure treatment conditions on the fungicidal enzymes,vitamin C,amino acid nitrogen,nitrite,apparent color and texture of pickled red pepper were studied.To explore the changes of quality between 40 days.To provide the theoretical and experimental basis for the application of ultrahigh pressure sterilization technology in prolonging the storage period and quality of pickled red pepper.The main results are as follows:1.The best proportion of pickled red pepper formula was studied.The best recipe for pickled red pepper was 100 grams of red pepper,0.03 grams of white sugar,0.03 grams of MSG,0.4 grams of white wine,4 grams of ginger,4.5 grams of garlic 2.5grams of vinegar and 6 grams of salt.2.The effects of ultrahigh pressure treatment on the total number of pickled red pepper colonies and E.coli were studied.The results showed that the total number of colonies in pickled red pepper was higher than 20 MPa,and the effect of bactericidal effect was proportional to the pressure and packing time.When the treatment pressure was 300 MPa and the packing time was over 15 min,Reaching 99%,E.coli not detected.Indicating that the ultra-high pressure treatment has the role of non-thermal sterilization,the bactericidal effect and heat sterilization(80?,15min)strength quite.3.The effects of ultrahigh pressure treatment on the activity of peroxidase and pectinase in the product were studied.The results showed that the enzyme activity was not inhibited by 100 to 200 MPa treatment,but the enzyme activity was slightly increased.When the pressure was over 200 MPa,the two enzyme activities were obviously inhibited or inactivated.The size of the enzyme was inversely proportional to the pressure and the holding time;The effect of ultrahigh pressure treatment on the activity of peroxidase was more significant.4.The effects of different ultrahigh pressure sterilization and heat sterilization on the quality of pickled red pepper were studied.The results showed that:(1)Nutrient quality: Vc content decreased with the increase of pressure,Vc content was only57.63mg/100 g at 500MPa/15 min,46.7mg/100 g in hot sterilization group and no significant The total acid content of heat sterilization group increased from 469.5mg/100 g to 502.3 mg/100 g.There was no significant change in amino acid nitrogen content in the ultrahigh pressure group,and the heat sterilization group decreased from 0.724% to 0.671%.The content of nitrite in the ultra-high pressure group decreased with the increase of the treatment pressure.When the applied pressure reached 500 MPa,the content decreased from 4.83 to 3.57 mg/kg.The effect of the holding time on the nitrite content was not obvious The heat sterilization group decreased from 4.64 mg/kg to 3.59 mg/kg.Indicating that the use of ultra-high pressure sterilization on the nutrient content of pickled red pepper is less than heat sterilization.(2)color quality: pickled red pepper after ultra-high pressure sterilization and heat sterilization treatment,L* value becomes smaller,a* value and b* value becomes larger,that pickled red pepper darkened,partial red and partial yellow level deepened,In the degree of change in the ultra-high pressure sterilization group were smaller than the heat sterilization group.This shows that the impact of ultra-high pressure on the color of the degree of less than hot sterilization.(3)Quality of texture:With the increase of pressure,the texture value of pepper showed a trend of increasing first and then decreasing.The hardness of 300MPa/15 min reached a maximum of8758.7g;cohesion at 200MPa/15 min reached a maximum of 0.645;elasticity at300MPa/15 min reached a maximum of 1.017;chewiness at 200MPa/20 min value reached a maximum of 4875.72;recovery in the 200 MPa When the peak reached0.482.The quality of the pickled red pepper was less than that of the ultrahigh pressure sterilization group.This shows that the effect of ultrahigh pressure treatment on the texture characteristics is better than heat treatment,and the treatmentconditions for the 300MP/15 min and 400MPa15 min,the best results.5.The effects of different bactericidal treatments on the indexes of preserved pickled red pepper were studied.The results showed that:(1)the total number of colonies and E.coli changes: the total number of colonies in each treatment group increased gradually,4? and 25? storage conditions,the total number of heat treated samples increased to 2.86 and 3.12 logarithm,300 MPa ultra-high pressure treatment Respectively,2.69 and 3.06 logarithms,400 MPa ultra-high pressure treatment were2.48 and 3.05 logarithm.(2)Changes in nutrient content: Vc content decreased gradually,Vc content of heat sterilization group was the lowest,and Vc content of low temperature storage decreased.The total acid content was lower than that of the hot sterilization group,and the total acid content in the low temperature storage was much lower than that at room temperature.Amino acid nitrogen content gradually decreased,low temperature storage decline rate is small.Nitrite content decreased rapidly fell to 90%.Indicating that low temperature storage helps to protect nutrients.(3)Apparent color change: the L* value of each treatment group decreased,low temperature storage changes in the small range.During the storage period,the a* and b* values of each treatment group gradually increased.Indicating that during the storage of pickled red pepper brightness weakened,partial red and partial yellow degree deepened.(4)texture characteristics: during the storage period,the different sterilization of pickled red pepper hardness,chewiness,elasticity,recovery and cohesion with the storage time is slow to decline,the adhesion showed a small increase in the first High,after the downward trend.At the 40 th day of storage,the gap between the treatment groups became smaller.The performance values of the heat sterilization group were lower than those of the ultrahigh pressure group and the low temperature storage.The change trend of each performance value was gentle.The use of a certain pressure and pressure of the long-term ultra-high pressure sterilization processing of pickled red pepper,compared with the heat sterilization,with the same sterilization effect of enzyme,and ultra-high pressure sterilization to maintain a high product hardness and quality,Longer storage period.The best effect of pickling red pepper treated with 300 MPa / 15 min ultrahigh pressure sterilization was obvious,and the effect of sterilization and keeping quality was obvious. |
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