Effects Of Flower Stage And Processing Methods On Bioactive Compound Contents And Antioxidant Capacity Of Bletilla Striata Flower

Bletilla striata(Thunb.)Reichb.f.is a perennial herb that is a traditional Chinese herbal medicine.B.striata flowers are purple and pink,it blooms from April to May every year.The flowers of B.striata are rich of bioactive compound contents and it alcohol extract have antioxidant effects.Since the medicinal part of B.striata is its dry tubers,and the flower is part of the plant on the ground.So there are few studies at home and abroad,and the utilization rate is low,which has affected the development and utilization of B.striata flowers.Therefore,this study used B.striata flowers as the research object,and studied the extraction process of anthocyanin,harvesting period and processing method.Find these how to effect the utilization and quality of B.striata flower.The main findings are as follows:1.This part of studies is aim to through the extraction of anthocyanins from B.striata flowers by microwave-assisted extraction.The test was based on four single factor parameters,that is microwave power,methanol concentration,extraction time and the liquid ratio.The response surface method was used to optimize the extraction process and a quadratic regression equation model was established.The test determined the best extraction method determined is:640 W microwave power,90%methanol concentration,22 min microwave time and 1:48 g/mL material to liquid ratio.In addition,the actual average extraction(6.68 mg/g)is basically consistent with the theoretical prediction(6.83 mg/g).So the results show that the theory model has good fitness with the reality practice.2.This test have use the same process method to processing sample of three stage B.striata flower.The three stage is the flower budding stage,initial flowering stage and flowering stage.In order to obtain the optimal harvesting time of B.striata flower,the test have studied the morphological differences and the dynamic changes of bioactive compound contents of B.striata flower.The results showed that there were significant differences in morphology,bioactive compound contents and antioxidant capacity between different flowering stages.Although the B.striata flower at the initial flowering stage was slightly worse than the flowering stage in the drying rate and the flower's browning degree.But in the initial flowering stage,the accumulation and antioxidant activity of the bioactive compound contents were better than flowering stage.In three flower stage,the initial flowering stage's total flavonoids(17.32 mg/g)and total polysaccharides(6.65 mg/g)were relatively high.The total phenol(19.09 mg/g)and total anthocyanin(5.49 mg/g)content was in the middle level.Although the total anthocyanin content of the initial flowering stage was slightly lower than that of the flowering stage(5.95 mg/g)of B.striata flower,but the difference between the two was not significant.In terms of antioxidant capacity,the B.striata flower at the initial flowering stage performed relatively well in reducing ability and DPPH free radical scavenging ability(456.80 ?g/mL).The flower budding stage and flowering stages were respectively strong in OH radical scavenging capacity(10480.50 ?g/mL)and ABTS free radical scavenging capacity(197.81 ?g/mL).Summary by experiment find that the order of harvesting suitable for B.striata flowers is:initial flowering stage>flowering stage>flower budding stage.3.This experiment was carried out on 6 kinds of processing methods for flowering period B striata flower,include of natural dry,hot air drying,vacuum drying,microwave drying,infrared drying,vacuum freeze drying.It aimed to found the difference in morphology,bioactive compound contents and antioxidant capacity between the different processing methods of B.striata flower.Experimental findings found,the impact of each indicator has a significant difference.The results show that there are two methods cost shorter drying time.The microwave drying method only need 0.87 h drying time to finish the drying and infrared drying need 7 h.But use the vacuum freeze-drying of B.striata flower has more vivid colors,lower degree of browning and could keep the original color of B.striata flower than other dry methods.Compared with the results of natural drying,vacuum freeze-drying's the retention of total polysaccharide(7.53 mg/g)was reduced,however the retention of total phenol(31.44 mg/g)and total anthocyanin(9.94 mg/g)both have significant increased.Under natural dry treatment,cost the long drying time and the degree of browning is large.Besides of these,the anthocyanins are almost completely degraded.However,the retention of total flavonoids(19.84 mg/g)and total polysaccharides(9.65 mg/g)both were in higher level.In terms of antioxidant capacity,natural dryness and vacuum freeze-drying both were showed better oxidizing power.The DPPH free radical scavenging ability(388.62 ?g/mL),ABTS free radical scavenging ability(171.29 ?g/mL)and OH radical scavenging ability(5234.61 ?g/mL)were relatively strong in natural dry treatment.Just only the reducing ability was slightly weaker than infrared drying and hot air drying.Taking into account factors such as commercial development and utilization of B.striata flower,we thought the vacuum freeze drying is more suitable to process B.striata flower,infrared drying for the second choice.