Antibacterial Effect Of Litsea Cubeba Oil And Its Application In Strawberry Preservation

Strawberry belongs to rosaceae,strawberry,and perennial herb.Its fruit is bright,soft,juicy and nutritious.However,due to the thinness of strawberry peel and high water content,post-harvest strawberries are highly susceptible to microbial contamination and rot and deterioration cause great losses to the strawberry industry.In this paper,the Hongyan strawberry and Zhangji strawberry of Changsha Farmer Ecological Strawberry Garden were used as the research object,and the strains causing their decay and deterioration under natural conditions were isolated and identified,and the inhibitory activity of the essential oil of Litsea cubeba on strawberry rot fungi was explored.Based on the single factor experiment of essential oil,chitosan,corn starch and glycerol,the orthogonal test was carried out to study the crack resistance,elongation at break,water vapor transmission coefficient and water solubility of the composite membrane.The film is optimally formulated and applied to the coating of strawberries.By measuring the rot rate,weight loss rate,fruit hardness,reducing sugar,vitamin C,anthocyanin,respiration rate and malondialdehyde content of strawberry,the preservation effect of Litsea cubeba oil chitosan composite wrap on strawberry was studied.In order to provide a theoretical reference for green,healthy and simple preservation methods.The main research contents are as follows:1.Isolation and identification of the rot-resistant species of Hongyan strawberry and Zhangji strawberry in Changsha Farmer Ecological Strawberry Park.The fungi that caused the two types of strawberry spoilage were Penicillium and Rhizopus,and the bacteria were Enterobacter and Alcaligenes.2.The antibacterial activity of the essential oil of Litsea cubeba on strawberry rot fungi,the MIC of Litsea cubeba oil to Penicillium is 25 ?L/mL,the MIC of Rhizopus is 50?l/mL,and the MIC of Alcaligenes is 100 ?L/mL and the Enterobacter MIC is 100 ?L/mL.The treatment of Litsea cubeba oil at 4 ?,25?,40?,121?,the inhibition zone is basically unchanged compared with normal temperature,indicating that the temperature does not affect the antibacterial activity of Litsea cubeba oil;The essential oil was placed in the environment of pH 4.0-pH 9.0,and the MIC of the test strain did not change,indicating that the pH value had no effect on the antibacterial activity of Litsea cubeba oil.3.The chitosan fresh-keeping composite film was prepared from the essential oil,chitosan,corn starch and glycerin of Litsea cubeba.Based on the single factor test,the fuzzy comprehensive scoring method was used to obtain the tensile strength of the composite membrane.Elongation at break,water vapor transmission coefficient and water solubility are the indicators to explore the best ratio of fresh-keeping raw materials.The results showed that 0.25%of Litsea cubeba oil,2.50%chitosan,0.4%corn starch and 0.75%glycerol were blended into a film,and the mechanical properties of the film were the best.4.The C.chinensis oil chitosan fresh-keeping composite wrap film was used for strawberry preservation,and the rot rate,weight loss rate,fruit hardness,reducing sugar,vitamin C,anthocyanin,respiration rate and malondialdehyde content were measured.The preservation effect of Litsea cubeba oil chitosan composite plastic wrap was studied and compared with the preservation of chitosan coating.It was found that the chitosan fresh-keeping composite film and chitosan fresh-keeping composite film could significantly reduce the strawberry rot rate,weight loss rate,fruit firmness,reducing sugar,vitamin C and cyanine at room temperature.A decrease in the rate of respiration,the rate of respiration,and the amount of malondialdehyde.The strawberry chitosan fresh-keeping composite film and the chitosan fresh-keeping composite film stored the strawberry for 9 days,but on the 9th day,the index of the chitosan oil-preserving composite film was superior to chitosan.Coating film.At 4 ?,the sweet-skinned composite film of Lirseacubeba oil stored the red strawberry for 18 days,and the strawberry was stored for 15 days.However,at 4 ?,there was no significant difference in the changes of various indexes of strawberry and chitosan composite coating film and chitosan coating.