| Red raspberry fruits are rich in polyphenols components which are closely related with their medicinal values and health-promoting value.The scientific and theoretical basis were provided for red raspberry seeds fully utilized.There are some major conclusions from this research work as follows:In this study,we have used the national standards methods,the appearance,grain weight,physical-chemical properties,nutrition components and bio-active compounds of five kinds of red raspberry(Heritage,Fertod Zamatos,Autumn Bliss,U.S.Raspberry and European red)seeds were analyzed and compared.The results showed that red raspberry seeds were small grain seeds with thousand seed weight of 1.06-1.60 g,water content of 3.23%-8.78%,crude fat content of 12.69%-16.65%,crude protein content of 4.64%-8.54%,total sugar content of 2.00%-4.26%,reducing sugar content of 0.97%-2.40%,crude ash content of 0.84%-1.57%,total polyphenols content of 15.21-18.53 mg/g,flavonoids content of 8.19-11.50 mg/g,procyanidins content of 19.43-31.10 mg/g.The contents of vitamin E in different varieties of red raspberry seed were 33.80-52.59 ?g/g,but vitamin A,D,K were not detected.Proximate analysis showed that the raspberry seeds were rich in mineral elements,proved to be a good source for minerals Ca,Co,Fe,K,P,and Autumn Bliss seeds had the most abundant mineral element content which was up to 3520.51 ?g/g.Ultrasonic extraction method was used to extract oil from 5 different varieties of red raspberry seed(U.S.Raspberry,Au-tumn Bliss,Heritage,Fertod Zamatos and European red)grown in northeast.The physicochemical properties were evaluated and the fatty acid composition of seed oil was analyzed by gas chromatography-mass spectrometry(GC/MS).Meanwhile,Schaal oven test was used to investigate the stability of red raspberry seed oil.The results showed that acid value of raspberry seed oil was 2.13-8.54 mg/g,saponification value was 125-168 mg/g,peroxide value was 0.27-2.72 mmol/kg,iodine value was 123-148 g/100g and raspberry seed oil was a kind of drying oil,fatty acid compositions of red raspberny seed oil were mainly unsaturated fatty acid,such as(Z,Z)-9,12-Octadecadienoic acid(45.38%-51.06%),(Z,Z,Z)-9,12,15-Octadecatrienoic acid(26.42%-32.31%)and(Z)-9-Octadecenoic acid(10.09%-14.00%);the stability of red raspberry seed oil was affected by light,temperature,oxygen and antioxidants,high temperature and oxygen could greatly promote the oxidation of red raspberry seed oil;high temperature(63 ±1 ?)could significantly promote the oxidation process of red raspberry seed oil,it was 7.21 times of that under ordinary temperature in 21 days;isolate oxygen could control the oxidation process,it was 6.20 times of that under aerobic condition in 21 days;it was 2.12 times of that under the protection from light condition in 21 days;antioxidants could delay the oxidation process,but the difference between the 3 synthetic antioxidants was not significant,and the effect of a-tocopherol was not as good as synthetic antioxidants.The single-factors tests and L9(34)orthogonal test were conducted to optimize the better conditions for extracting polyphenols from red raspberry seed,and the Duncan's Mutiple-Range test was chosen to examine the significant differences among each treatment.The results showed that the optimal extraction conditions for polyphenols were as following:60%(V/V)ethanol concentration,extraction temperature at 50 ?,ratio of material to solvent for 1:45(g/mL);extraction time for 4h;The response surface experiment to optimize the extraction conditions was obtained that 57%ethanol concentration,extraction temperature at 51 ?,ratio of material to solvent for 1:50(g/mL),extraction time for 3.5 h.Under such conditions,the contents of polyphenols were 38.32 mg.The results indicated that the extraction technology was reliable,stable and practical.HPLC-MS was applied to explore the composition of polyphenols from red raspberry seed extracts.The phenolic compounds in red raspberry seeds were ferulic acid,rutin,caffeic acid,gallic acid,vanillic acid,pcoumaric acid.Further determination were needed to detect other phenols.The antioxidant capacities,hypolipidemic,antimicrobial activity of ethanolic extracts from five different varieties of red raspberry seed extracts were evaluated.The antioxidant activities of red raspberry seed extracts were determined by hydroxyl radical(·OH),DPPH·radical,ABTS+· radical scavenging capacity and ferric reducing/antioxidant power(FRAP).Human gastric and intestinal pH environment was simulated to explore the capacity of different varieties of red raspberry seed extracts for binding cholesterol and sodium taurocholate,valuating the hypolipidemic effect in vitro.Moreover,the minimum inhibitory concentration(MIC)was tested to investigate the antimicrobial activities.Results showed that the highest contents of flavonoids and proanthocyanidins were determined in red raspberry seed extracts from the U.S.Raspberry variety.The highest content of total phenols was detected in Fertod Zamatos red raspberry seed extracts.The results of this study implied that red raspberry seed extracts from the U.S.Raspberry and European red raspberry varieties had stronger antioxidant activities.There were correlations between the contents of total phenols or flavonoids and antioxidant capacities.Red raspberry seed extracts had a significantly better cholesterol absorption ability at pH 7.0 than that at pH 2.0.And the sodium taurocholate adsorbabilities of 5 red raspberry seed extracts were strong.The antimicrobial activity of five different varieties of red raspberry seed extracts against Escherichia coli was the strongest,compared with Bacillus subtilis and Staphylococcus aurous.No inhibition of yeast and mould. |
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