| Mulberry fruit are the fruits of mulberry trees,which have high nutritional value and health protection function.It was listed as one of the medicine and food products by the Ministry of health.The nutrition is abundant,which is rich in saccharides,organic acids,vitamins and trace elements,and free amino acids.Because of the high moisture content,the skin is thin and easy to break,easy to mildew and rot after harvest,the ability of storage and transportation is poor.These reduce the market value of mulberry fruit.More and more attention has been paid to the preservation of mulberry fruit.In order to explore the new method of preservation of mulberry,this paper studied the bacteriostatic effect of 15 kinds of Chinese herbal medicine on the GA,one fungus of mulberry fruit rot-causing,in vitro.The Chinese herbal medicine,which has the best bacteriostatic effect was screened.To study the preservation effect on mulberry fruit,Chinese medicine extraction,the suspension of Bacillus subtilis and the compound were used to treat the mulberry fruit.Extraction of 15 kinds of traditional Chinese medicine were extracted by ultrasonic-assisted method.The antibacterial effect of traditional Chinese medicine on GA was screened by bacteriostatic test in vitro with the index of bacteriostatic circle diameter,culture medium of potato dextrose medium.The optimal extraction processes of the ethanol concentration,the ultrasonic extraction time and ultrasonic power,were determined by Response Surface Methodology with the index of bacteriostatic circle diameter.Results showed that Coptis chinensis,Cortex phellodendri,Syzygium aromaticum,Asarum sieboldii,Scutellaria baicalensis all have the bacteriostatic effect on GA,and Coptis chinensis is the best one.The optimum extraction condition is ethanol concentration of 50%,ultrasonic extraction time of 72 min,ultrasonic extraction power of 400 W.Under the optimization conditions,the actual value is 15.98 mm,and the antibacterial circle diameter's predicted value is 16.20 mm,only a difference of 1.36%.The optimal extraction condition has good practical value.To analysis the effects of different concentrations of coptis extracted under the condition of the optimal extraction to mulberry fruits preservation,the weight loss rate,decay rate,total soluble sugar,the titratable acid content and MDA content were determined.Compared with untreated mulberry fruits,the weight loss rate and decay rate decreased,the peak value of soluble sugar could be delayed for two days,the drop of titratable acid content and the add of MDA content decreased.Mulberry fruits disposed by 0.5g/mL and 0.7g/mL coptis extract showed more efficiency on preservation among six different concentrations.The weight loss rate,decay rate and MDA content were lower than others while total soluble sugar and the titratable acid content were higher.On the eighth day,the weight loss rate,decay rate and MDA content decreased by 26.25%,58.62% and 47.47%,and the titratable acid content increased by 83.55%Mulberry fruits were treated by different concentrations of coptis extract and Bacillus subtilis,as well as the combination with both.The weight loss rate,decay rate,total soluble sugar,the titratable acid content and MDA content were determined to analyze the effect of mulberry fruit preservation.All the treatment had good effects on preservation,and the compounded disposal was the best.On the fifth day,the weight loss rate,decay rate and MDA content reached the lowest level,decreased by 26.25%,58.62% and 47.47% compared to the untreated mulberry fruits.At the same condition,the titratable acid content reached the highest value which was about 1.5 times of the untreated mulberry fruits.Also the peak value of soluble sugar could be delayed for two days. |
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