Study On The Effect Of Processing And Packaging On The Shelf Life Of Fried Peanuts

Fried peanuts are one of the main product forms of peanut snacks.Because of the high fat content and the large proportion of unsaturated fatty acids,fried peanuts are susceptible to oxidative deterioration and it becomes bottleneck that limits expiration of fried peanuts.This paper takes peanuts as research object,researching on the effects of packaging technology,frying process and antioxidant on expiration.The concrete results are as follow:(1)Research on expiration of fried peanuts packaged in different barrier packaging materials and packaging technology,it is found that the barrier properties of the packaging materials had a significant effect on the expiration of fried peanuts,and the expiration of high barrier plastic materials with an oxygen permeability of 5.84 mL / m2·day was significantly(P <0.05)longer than the medium barrier plastic material with an oxygen permeation rate of 51.81 mL / m2·day.Under the condition of storage at 45 ℃,the expiration of the former is longer than that of the latter by 39%.For packaging technology,contrasting vacuum deoxidation packaging and vacuum packaging,vacuum deoxidation packaging can significantly(P <0.01)extend the expiration of fried peanuts,on the condition of 45℃,the former is 2.87 times as long as the latter.Using high barrier Plastic material combined with vacuum deoxidation packaging,can maintain the expiration of more than one year at room temperature.Nitrogen filling can effectively prolong the expiration of fried peanuts,but the way of nitrogen enrichment has a huge effect on expiration and vacuum compensation nitrogen filling is more effective.By detecting,the way of nitrogen enrichment will significantly affect the resid ual oxygen of the bag,thus affecting packaging effect.In order to achieve long expiration,the oxygen residue in nitrogen-filled package should be less than 4.5%.Compared with the change of the peroxide value and the acid value during the storage,it is found that the acid value shows little change,and the change of POV was more significant.For fried peanuts,peroxide value can more accurately reflect the expiration changes.(2)Research on effect of antioxidants on expiration of fried peanuts shows that the effects of three antioxidants on POV were significantly different.Under the same concentration,the antioxidant ability is in order of : TBHQ> carnosic acid> VE.TBHQ can significantly(P <0.05)prolong the expiration of fried peanuts.The antioxidant effect of carnosic acid was not obvious and VE could increase oxidation rate of fried peanuts.The change of TBHQ content in the process of frying shows that the content of TBHQ in frying oil continued to decrease with frying times increasing.The loss of TBHQ at different temperatures shows that there was a jump point at TBHQ loss rate.The loss rate was 18.4% at 155 ℃ and 18.3% at 160 ℃ for two hours’ heat preservation.The loss rate at 165 ℃ was 29.3% and it increased significantly.Research on correlation between the content of TBHQ in frying oil and the content of TBHQ in fried peanuts shows that content of TBHQ in frying oil was significantly correlated with the content of TBHQ in fried peanut.The correlation coefficient was R2=0.9673,which indicated tha t under the same process,through the frying oil in the TBHQ content can be estimated fried peanuts in the corresponding content of TBHQ.Research shows that the addition of TBHQ in the frying oil is controlled in the range of 1.0-1.4g / K g under the curre nt frying process,which can guarantee the expiration of fried peanuts and ensure that TBHQ does not exceed the national limit.(3)Research on effect of frying process on expiration of fried peanuts shows that:The deoiling process reduces the oil content of fried peanuts,but accelerates the oxidation of fried peanuts.The morphological characterization of peanuts by scanning electron microscopy shows that deoiling process will lead to the full exposure of the frying peanuts internal voids,increase the contact area with oxygen and accelerate the oxidation process,which has an bad influence on the expiration of fried peanuts.Whether vacuum frying or conventional frying,the temperature in the frying process showed a tendency to decrease first and then rise.Vacuum fry drops more rapidly,and the temperature rises back slowly.Compared with conventional frying,the vacuum frying process can significantly improve the quality of fried peanuts,color and crisp better,and POV lower.The optimum vacuum frying conditions are: frying temperature of 195℃ and frying for 14 min.