Study On Storage Quality Of Fresh-Cut Radish Treated With Ultraviolet And Coated Film

The proportion of fresh-cut fruits and vegetables in the fruit and vegetable market has increased year by year.More and more fruits and vegetables have been processed into fresh-cut products,but the fresh-cut fruits and vegetables have a short shelf life and greatly reduce their commercial value.At present,a large number of researchers use different preservation techniques to improve the quality of fresh-cut fruits and vegetables and extend shelf life.In this paper,the unique Shawo radish was used as raw material in Tianjin,and it was processed into fresh-cut products.The UV-C irradiation combined with the composite coating technology was used to treat the Shawo radish after cutting,through the measurement results of various indicators,the optimal irradiation conditions and composite coating film formula were selected.The effects of different packaging methods and different storage temperatures on the quality of fresh-cut Shawo radish were studied,and the optimal preservation parameters of fresh-cut Shawo radish were determined.The test results are as follows:（1）The fresh-cut Shawo radish was irradiated on both sides with an ultraviolet lamp with an irradiation dose rate of 0.45 mW/cm²,and the irradiation time was 0,2,4,6,and 8min,respectively,and the fresh-cut Shawo radish was periodically measured.The results showed that:UV-C double-sided irradiation for 4 minutes can effectively inhibit the growth and reproduction of fresh-cut Shawo radish microorganisms,slow down the weight loss rate,and decrease the VC content,SSC content,total acid content and hardness,and maintain better sensory quality and nutritional quality.（2）After the fresh-cut Shawo radish is treated by the best UV-C,the single factor test of the film showed that the single use of chitosan,citric acid,calcium lactate and natamycin can improve the fresh-cut Shawo radish to some extent during storage;the four kinds of preservatives were orthogonally optimized to obtain a composite coating solution with1.0%chitosan+1.5%citric acid+0.8%calcium lactate+0.01%natamycin,and the soaking time was at 3 min,the fresh-cut Shawo radish treated with the composite coating solution maintained a good sensory quality on the sixth day under the storage environment of 10°C,which was better than the single use preservative.（3）Fresh-cut Shawo radish was treated with UV-C and coating film,and then stored in fresh-keeping box,vacuum packaging and nitrogen-filled packaging to study the best packaging method.The results showed that fresh box packaging has a poor preservation effect.The fresh-keeping effect of vacuum packaging and nitrogen-filled packaging on fresh-cut Shawo radish was not significantly different in the early storage period,and the vacuum packaging group was superior in the later stage.It is concluded that the best packaging method for fresh-cut Shawo radish is vacuum packaging.During the storage period of 0-10 days,the vacuum packaging group effectively improved the sensory quality of fresh-cut Shawo radish.The VC content only decreased by 29.03%,and the SSC content and total acid content decreased by 11.51%and 43.53%,respectively.It decreased from21.8kg·cm^-2 to 19.16kg·cm^-2,and it can significantly inhibit the activity and respiration rate of POD,thus slowing down the aging process of radish.The vacuum packaging also keeps the fresh-cut Shawo radish in good moisture and color during the shelf,inhibits the growth and reproduction of microorganisms,and has a remarkable preservation effect.（4）The Shawo radish after the division was sequentially subjected to UV-C irradiation,composite coating film and vacuum packaging,and then the changes of various indexes of fresh-cut Shawo radish at 0°C,5°C and 10°C were studied.5°C is the best storage temperature.During the storage period of 0-12 days,the quality of fresh-cut Shawo radish in the 5°C group was better,the sensory score was higher,the hardness was only decreased by 14.73%,and the weight loss rate was only 1.57%,which delayed the occurrence of sputum.The SSC content and total acid content decreased slowly.The VC content decreased from 24mg/100g to 16.24mg/100g,and the respiratory rate and POD activity were significantly inhibited.During the whole storage period,the total number of microorganisms does not exceed the edible range,and the preservation effect preferably.In summary,the best processing technology of fresh-cut Shawo radish:fresh Shawo radish→5°C pre-cooling→fresh cut treatment→0.45 mW/cm² UV-C double-sided irradiation for 4 min→composite coating liquid（1.0%Chitosan+1.5%citric acid+0.8%calcium lactate+0.01%natamycin）soak for 3min→vacuum packaging（PVDC packaging bag）→storage at 5°C,Under these conditions,the fresh-keeping period of fresh-cut Shawo radish can reach 12d.