| This study aimed at commercial cranberry frozen fruit, the cranberry extracts(CE) with high content of anthocyanins as well as antioxidant activity was prepared, and the antioxidant activity and oxidation stability of extracts under different conditions were explored, at the same time, we also studied the restorative effect of cranberry extract on junction of inflamed Caco-2 Cells. The experimental results are as follows:First of all, the optimum extraction conditions of cranberry extract were explored. The extract with high anthocyanins content was extracted with 65% ethanol and 1% acetic acid for 2 h, and the material liquid ratio is 1:20, the anthocyanins content of the cranberry extract is 23.29 mg/L.Secondly, the anti-oxidation activity stability and the anthocyanins content of cranberry extract were studied in different storage conditions.(1) Extract is concentrated by rotary vaccum evaporator at 40 ℃until the total anthocyanins content is around 100 mg/L. The anthocyanins content and antioxidant activity at 60, 80, 100℃ during 8 hours were investigated respectively. The result showed that anthocyanins content was decreased during the heating, and its degradation conformed with the first order reaction kinetics. The half-life period decreased in the degradation process, and the reaction ra te constant increased as well with the temperature increasing. With the increasing of heating temperature and longer heating time, anthocyanins content, polyphenol content, hydroxyl and superoxide r adical scavenging activity were decreased respectively, the reducing power also declined in varying degrees. Higher temperatureand longer heating time induced a bigger reduction degree.(2) The condensed cranberry extract was diluted using buffer(p H 3), the variation of anthocyanins content, polyphenol content and antioxidant activity in sample under natural light and dark place were determined respectively. Results showed that degradation of anthocyanins content in natural light condition was faster than dark environment, and the degradation corresponded to the first order reaction kinetics. Hydroxyl and superoxide radicals scavenging rate of the sample as well as total reducing power declined. Therefore natural light had greater effect than dark light and the antioxidant activity decreased with the extended exposure time.(3) The p H value of cranberry extract was adjusted to 2,3,4,5,6,7, respectively. The anthocyanins content, polyphenol content and antioxidant activity of the samples were determinated during 25 days storage. Results showed that the stability of anthocyanins would be influenced by p H value. The change of anthocyanins content and antioxidant activity was smallest in p H 3, the cranberry extract showed the stable antioxidant activity at low p H and decreased a lot at high p H(P<0.05).Thirdly, using liquid chromatograph/mass spectrometer to identify the ingredients of cranberry polyphenol in extract, 12 kinds of extract were determined, many kinds of anthocyanins and A-type procyanidins, as well as many polyphenol such as resveratrol were included.Finally, the restorative effect on Junction of Inflamed Caco-2 Cells was determined by RT-QPCR. The inflammory Caco-2 cells which were stimulated by IL-1β showed high level expression of TNF-α and IL-8, on the contrary, expression of Occludin and ZO-1 were decreased significantly(P<0.05). Through the investigation of cytokine concentrations, it could be concluded that samples datas had no significant difference with control group. However,these changes could be restorated under low concentration extract addition.In conclusion, the study established an comprehensive evaluation method for antioxidant activity and stability of cranberry frozen fruit, the results can lay the function for the next researches about anti-inflammory ability of the extract against Caco-2 Cells. |
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