Changes Of Polyphenolsduring Theraspberry Fruits Ripening And Their Extraction And Application

In the era of healthy concept leading the trend,promoting the transition from disease medicine to healthy medicine is a research focus.Raspberry?Rubus idaeus L.?,as the“third generation fruit”,is homologous to medicine and food.It is not only rich in nutrients,but also contains many natural active ingredients such as anthocyanins,flavonoids and so on.Therefore,raspberry has important application value in food,health and cosmetics industries.This paper analyzed the indicator changes of raspberries in different varieties and maturity.And then,the study was carried on the extraction condition of anthocyanins in raspberry pomace,purification,components analysis,antioxidant activitiesand prepareration of its pH-indicator film.We hope this study can provide more ideas and support for the diversified development of the raspberry products and the comprehensive development of raspberry resources.The main results were as follows:?1?The raspberry fruits of the three cultivars?Reveille?,?Tulameen?and?Heritage?at five different ripening stages were collected in Shanxi Province.Changes of evaluation indicators of fruit quality and the total content of polyphenols were determined by colorimetry,and the content of 15 polyphenols were traced by HPLC-MS.The results showed that fruit weight,moisture content,soluble solids,reducing sugars content,total sugars content and sugar-to-acid ratio increased during raspberry ripening,but titratable acid content,protein content and the activity of superoxide dismutases decreased during raspberry ripening.The total content of polyphenols decreased followed by increasing during raspberry ripening,among which,the content of anthocyanins increased gradually,while the content of non-anthocyanol polyphenols decreased gradually.Therefore,the content of non-anthocyanidin polyphenols contained in green unripe fruits was 1220.56-1660.16 mg/kg,which was twice that of ripe fruits,and the main compounds were epicatechin,proanthocyanidin B1,ellagic acid and quercetin-3-O-glucuronide.So that the unripe fruits during cutting and pruning can be used as raw materials for the development of plant polyphenols.The pink and red ripe fruits had higher average fruit weight of 1.60-3.87 g,water content of 84.67%-86.70%,and the ratio of sugar to acid of 2.31-3.75,which is the best choice for harvesting and selling.In addition,the content of anthocyanins in deep red overripe fruits was 455.06-1025.88 mg/kg,which was 20-60 times that of unripe fruits,and the main compounds were cyanidin-3-O-rutinoside,cyanidin-3-O-glucoside and cyanidin-3-O-sophoroside in cultivars?Reveille?,?Tulameen?and?Heritage?,respectively.Therefore,the overripe fruits were the best source of natural pigment.?2?Anthocyanins was extracted from fresh raspberry pomace and dried mulberry fruit,and the extraction conditions were optimized by response surface optimization method.Comparing the two optimal extraction conditions,it is concluded that the optimal extraction conditions of anthocyanins of different berry materials is the same under the same experimental environment conditions,that is,1:50?g dry weight/mL?of the ratio of material to liquid,75%of ethanol concentration,3 of extractant pH,60?of temperature,30 min of time,150 W ofultrasonic power.Under these conditions,the anthocyanins content extracted from fresh raspberry pomace and dried mulberry fruit were 4.6 mg/g?dry weight?and 17.2mg/g?dry weight?.For materials with different moisture content,it need to convert the moisture content to obtain the appropriate material-liquid ratio.This conclusion will provide convenient support for the research on other materials.?3?After the raspberry pomace extract I was purified with macroporous resin,the extract II was obtained.The polyphenols content and the antioxidant activities of raspberry pomace extract II were compared with those of the extracts of raspberry leaves and unripe raspberry?Traditional Chinese medicine?.The raspberry pomace extract II contains anthocyanins?75.42mg/g?and the highest content of total flavonoids?416.73 mg/g?,but the total polyphenols content?309.53 mg/g?and antioxidant activity(19.98?g/mL of IC_50DPPH and 5.18?g/mL of IC_50ABTS)were the lowest.The content of total polyphenols and total flavonoids in the extract of unripe raspberry was higher than that of leaves extract,and the ability to scavenge free radicals of ABTS was the strongest,but the scavenging ability of DPPH free radicals was slightly lower than that of leaves extract.The main anthocyanin in the extract II of raspberry pomace was cyaniding-3-O-rutinoside,content of 212.56?g/g accounted for 42.15%of the total anthocyanins content.The main non-anthocyanins polyphenol was procyanidins B1,content of 10631.62?g/g accounted for 40%of the total content,followed by epicatechin,quercetin-3-O-glucuronide and ellagic acid.Ellagic acid was also the main polyphenol in the extracts of raspberry leaves and unripe fruit,and quercetin-3-O-glucuronide was another main polyphenol in the extract of raspberry leaves.?4?Using the chemical properties of anthocyanins in response to acid to redness and alkali to blue,sodium alginate and pectin were used as raw materials and the raspberry pomace extract II was added to prepare a pH-indicator film.The addition of raspberry pomace extract II enhanced the tensile strength and elongation at break,and reduced the transparency of the film.The indicator film was red and different methods of monitor forpork and soybean milk during the putrefaction showed different color changes.However,both of them could be clearly observed by the naked eyes,which showed certain practicability and feasibility of the indicator film in the monitoring of protein food freshness...