Study On Phenolic Compounds Of Mulberry Fruit And Whole-component Juice Development

Mulberry fruit is a significant source of polyphenols,which has a variety of positive effects on human health.However,the composition and content of polyphenols vary significantly among different mulberry cultivars.Breeding program of China focus predominantly on creating cultivars improved commercial traits(high productivity,large size,desirable flavour and disease resistance).However,there was less attention to polyphenols in mulberry cultivars.The composition and content of polyphenols and their antioxidant activity were compared in thirteen mulberry cultivars(Yichuanhong,Qiong46,Guoshang8632,Yuebanguo,Yueshen28,Yueshen74,Da10,Jinqiang63,Yunguo1,Heizhenzhu,Xuanguo1,Guiyou12 and Shansang).The suitable mulberry cultivar was selected as raw materials.The whole-component mulberry juice beverage was developed based on the industrial-scale microfluidizer system(ISMS),and the best preparation condition was determined.The storage changes of the wholecomponent mulberry juice beverage was explored and label of product was designed.The purpose of this research is to provide a reference for the comprehensive application of mulberry fruit.The main findings are as follows:1.The soluble solids(TSS),titratable acid(TA),total phenolic content(TPC),total flavonoid content(TFC),total anthocyanin content(TAC),composition and content of polyphenols and antioxidant activity were determined in different mulberry cultivars.The results showed that TSS(6.20-15.83 °Brix),TA(5.82-48.49 g CA/kg),TPC(10.82-27.29 mg GAE/g),TFC(2.91-11.86 mg CE/g),TAC(2.91-11.86 mg CE/g),content of individual polyphenols and antioxidant activity in cultivars varied significantly,and there was a significant positive correlation between TPC,TFC,TAC and antioxidant activity;The results of principal component and hierarchical cluster analysis showed that: according to the difference between the content of individual polyphenols and antioxidant activity among the cultivars,thirteen cultivars had a clear clustering trend and was divided into three parters.From the perspective of promoting health,cultivar Qiong 46,Yuebanguo and Heizhenzhu contained higher TPC,TFC,TAC,content of individual polyphenols and stronger antioxidant capacity,which have higher commercial value.The results of this parter can provide a certain theoretical reference for the breeding of mulberries and high value-added processing.2.Considering Da 10 as raw material,the whole-component mulberry juice beverage was developed based on the ISMS.The ISMS pressure,white sugar amount,thickener type,and thickener amount are optimized by the single-factor test.The apparent stability,particle size,centrifugal precipitation rate,total free phenolic content,total combined phenolic content and sensory evaluation were determined.The best preparation conditions of the whole-component mulberry juice beverage: 90 MPa of ISMS,white sugar content 10%,CMC-Na content 0.4%.The whole-component mulberry juice beverage with good sensory evaluation and stability can be prepared by this process.3.The quality changes of the whole-component mulberry juice beverage was studied under different storage conditions(4°C,28°C,38°C)for 90 days.During the entire storage period,the soluble solid content,p H value,particle size and instability index of the beverage not varied significantly;The slight aggregation and fracture were found in the beverage storaged at 38°C for 90 days;The color changes of the beverage varied significantly during the storage process,higher storage temperature and greater change in color;Total phenolic content and total anthocyanin content also decreased with the storage time,the higher storage temperature and the larger the reduction;During the entire storage time,total number of bacterial colonies in the beverage always meeted the official standard.Through storage experiments,it was calculated that the shelf life of whole-component mulberry juice beverage at room temperature storage(25°C)is four months,and the shelf life of cold storage(4°C)is six months.According to the relevant regulations of label design in China,the label of the wholecomponent mulberry juice beverage was designed.