Study On Antioxidation,Bacteriostasis And Application Of Herbaceous Peony Polyphenol

Herbaceous peony(Paeonia lactiflora Pall.),as the "Prime Minister of Flowers",has been favored by the fresh cut flower market due to its symbolism of wealth and auspiciousness,and has developed rapidly in China recent years.Herbaceous peony has rich flower colors with many petals.However,the flowering period of herbaceous peony is short and concentrated,and a large number of petals wither and fall after the flowering period,causing great waste of resources.Therefore,it is urgent to solve the problem of further developing and utilizing the petals of herbaceous peony after the flowering period,which is of great significance for improving the resource utilization rate of herbaceous peony,extending the industrial chain of herbaceous peony,and increasing its economic value.This study used the petals of herbaceous peony called ’Danfeng’ as the materials.Firstly,the ultrasonic extraction process optimization of herbaceous peony polyphenols was studied.Secondly,the antioxidant and antibacterial functions of herbaceous peony polyphenol extract were evaluated,and its development and application in products such as hand cream,bath soap,and cut flower preservation solution were also carried out.The main research findings are as follows:(1)The herbaceous peony petals were pretreated in three ways,and the dried petals had the highest polyphenol content.Among the five factors of ultrasound time,ultrasound temperature,ethanol concentration,ultrasound power,and material to liquid ratio,the three factors of ultrasound time,ethanol concentration,and material to liquid ratio have a significant impact on the ultrasonic extraction of herbaceous peony polyphenols.Furthermore,through mathematical models and regression equations,the optimal ultrasonic extraction conditions for paeoniflorin were obtained as follows:material liquid ratio 1:46,ethanol concentration 43%,ultrasonic time 31 minutes,and the extracted polyphenol content could reach 745.26 ± 2.79 mg GAE/g.(2)The antioxidant capacity of herbaceous peony polyphenols was significantly positively correlated with their concentration within a certain range.The total antioxidant capacity of herbaceous peony polyphenols reaches its maximum at a concentration of 3 mg/mL,while herbaceous peony polyphenols have a significant impact on the scavenging effect of O2·-,OH-,and DPPH radicals reached its highest at a concentration of 5 mg/mL.Further use Analytic Hierarchy Process(AHP)to construct a sensory evaluation system for the prepared herbaceous peony polyphenol hand cream,consisting of 12.53%stickiness,47.12%moisture,11.96%luster,and 28.39%softness.Based on the constructed evaluation system,the optimal formula for herbaceous peony polyphenol hand cream was obtained as follows:68%herbaceous peony polyphenol extract,30%oil phase(sweet almond oil,coconut oil,glycerol),2%emulsifier,and others.Through the observation of the appearance,aroma,pH,storage stability,heat resistance,cold resistance,total number of colonies,mold and yeast,thermotolerant Escherichia coli,Staphylococcus aureus,Pseudomonas aeruginosa and other indicators of the prepared herbaceous peony polyphenol hand cream,the results are in line with the industry standard QB/T1857-2013.(3)The minimum inhibitory concentration(MIC)of herbaceous peony polyphenols against five common bacteria in human epidermis,including Escherichia coli,Trueperella pyogen,Staphylococcus epidermidis,Pseudomonas aeruginosa and Staphylococcus aureus,was 0.8%,and the inhibition rates were 92.10%,94.35%,98.52%,99.24%and 99.01%,respectively.By comparing the size of the bacteriostatic zone,the bacteriostatic performance of herbaceous peony polyphenols against five kinds of bacteria is as follows:Staphylococcus epidermidis>Staphylococcus aureus>Pseudomonas aeruginosa>Escherichia coli>Pyogenic bacteria,and the bacteriostatic effect reaches its maximum at 24h.The appearance,odor,user experience,dry soap content,ethanol insoluble content,free alkali content,total free alkali content,moisture and volatile matter content of the prepared herbaceous peony polyphenol bath soap were evaluated and measured,and the results all met the national standard QB/T 2485-2008.(4)Herbaceous peony polyphenols can significantly prolong the vase life of cut herbaceous peony flowers,increase the fresh weight and flower diameter of cut herbaceous peony flowers,increase the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and soluble protein content of cut herbaceous peony flowers,and effectively reduce the content of malondialdehyde(MDA).In addition,herbaceous peony polyphenols maintain water balance in cut herbaceous peony flowers by regulating the expression of aquaporins(AQPs),reducing water loss in cut herbaceous peony flowers.In addition,a fungus belonging to the Aspergillus genus was identified from the stem base of cut herbaceous peony flowers,which blocked the stem base.Herbaceous peony polyphenols have a significant inhibitory effect on Aspergillus spp.,reducing the blockage at the stem base.Further evaluation of the prepared herbaceous peony polyphenol preservation solution showed that its appearance was clear,transparent,light yellow,fragrant,and slightly acidic.It should be stored in a cool and dark place.