Flos Sophorae Immaturus(FSI)extract and its main active secondary metabolites have health benefits including antioxidant activity,but the drying process may negatively affect their quality and quantity.To investigate ...Flos Sophorae Immaturus(FSI)extract and its main active secondary metabolites have health benefits including antioxidant activity,but the drying process may negatively affect their quality and quantity.To investigate the effect of ultrasound-assisted freeze-drying(UAFD)on FSI,the drying rate,colour,and microstructure samples were analysed.Furthermore,the flavonoids and antioxidant activity of dried products were evaluated.The results showed that the drying rates were significantly enhanced with UAFD.At 600 W and 15 min,the drying time of UAFD was 40%shorter than that of freeze-drying(FD)alone.The micrographs showed that USAD created more porous structures that allowed water to migrate outward from inside the FSI tissue.Processing conditions of 600 W ultrasonic power and 5 min ultrasonication time produced better antioxidant activity in dried products than in other conditions.The highest characteristic properties were DPPH(75.51%),ABTS(95.14%),FRAP(83.05%),acceptable drying time(3 h),and low colour difference(1.09).Under these conditions,the contents of total flavonoids(298.34 mg/g),rutin(256.66 mg/g),quercetin(20.13 mg/g),kaempferol(19.64 mg/g),isorhamnetin(17.77 mg/g),and genistein(13.97 mg/g)were determined to be as indicated.The results confirmed the obvious benefits of incorporating the ultrasonic effect into the FD method.展开更多
为了对发酵桑叶茶工艺条件进行优化并探究桑叶茶经发酵后抗氧化活性的变化,该试验通过响应面分析法确定发酵桑叶茶在发酵温度、发酵时间和黑曲霉接种量3种变量条件下的最佳工艺条件,并测定发酵桑叶茶生物活性物质含量及其抗氧化性。结...为了对发酵桑叶茶工艺条件进行优化并探究桑叶茶经发酵后抗氧化活性的变化,该试验通过响应面分析法确定发酵桑叶茶在发酵温度、发酵时间和黑曲霉接种量3种变量条件下的最佳工艺条件,并测定发酵桑叶茶生物活性物质含量及其抗氧化性。结果表明,最佳工艺条件为发酵时间5 d 16 h,发酵温度30℃,接种量16.55%,此条件下所制发酵桑叶茶感官评分高达90分,且其总黄酮、总多糖、多酚、游离氨基酸、芦丁、槲皮素含量比桑叶绿茶分别升高了14.39%、12.67%、2.90%、3.46%、81.13%、19.35%,还检测到了含量7.55%±0.37%的茶褐素。此外,1/1000(g/mL)浓度下发酵桑叶茶对羟基自由基、DPPH自由基、超氧自由基的清除率和对二价铁离子的螯合率分别是桑叶绿茶的1.16倍、1.07倍、1.06倍和0.82倍,该研究结果为今后桑叶的进一步开发与应用提供理论基础和参考。展开更多
采用烘制和烤制2种不同加工工艺制备黄精茶,并对其质构特性、挥发性成分、感官品质及抗氧化作用进行对比分析。结果表明,不同加工工艺对黄精茶色泽影响较大,但对其复水比、皱缩比及微观组织结构等质构特性影响不显著。固相微萃取/气相色...采用烘制和烤制2种不同加工工艺制备黄精茶,并对其质构特性、挥发性成分、感官品质及抗氧化作用进行对比分析。结果表明,不同加工工艺对黄精茶色泽影响较大,但对其复水比、皱缩比及微观组织结构等质构特性影响不显著。固相微萃取/气相色谱-质谱联用(solid phase microextraction combined with gas chromatography-mass spectrometry, SPME/GC-MS)分析结果表明,烘制和烤制黄精茶的主要呈香物质相似但含量不同,以烷类及芳香族化合物为主,而苯乙醇、甲基丁香酚、桉叶油醇可能是黄精茶特征性风味物质。感官品质以烘制黄精茶相对较好。与烤制黄精茶相比,烘制黄精茶更好地保留了总酚、总黄酮等生物活性物质,并具有更为显著的ABTS阳离子自由基、DPPH自由基清除作用。该研究为黄精的有效开发与利用提供了理论参考。展开更多
基金supported by the General Project of Modern Agriculture in Jiangsu Province,China(BE2019309)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2021L566),which has enabled us to accomplish this study.
文摘Flos Sophorae Immaturus(FSI)extract and its main active secondary metabolites have health benefits including antioxidant activity,but the drying process may negatively affect their quality and quantity.To investigate the effect of ultrasound-assisted freeze-drying(UAFD)on FSI,the drying rate,colour,and microstructure samples were analysed.Furthermore,the flavonoids and antioxidant activity of dried products were evaluated.The results showed that the drying rates were significantly enhanced with UAFD.At 600 W and 15 min,the drying time of UAFD was 40%shorter than that of freeze-drying(FD)alone.The micrographs showed that USAD created more porous structures that allowed water to migrate outward from inside the FSI tissue.Processing conditions of 600 W ultrasonic power and 5 min ultrasonication time produced better antioxidant activity in dried products than in other conditions.The highest characteristic properties were DPPH(75.51%),ABTS(95.14%),FRAP(83.05%),acceptable drying time(3 h),and low colour difference(1.09).Under these conditions,the contents of total flavonoids(298.34 mg/g),rutin(256.66 mg/g),quercetin(20.13 mg/g),kaempferol(19.64 mg/g),isorhamnetin(17.77 mg/g),and genistein(13.97 mg/g)were determined to be as indicated.The results confirmed the obvious benefits of incorporating the ultrasonic effect into the FD method.
文摘为了对发酵桑叶茶工艺条件进行优化并探究桑叶茶经发酵后抗氧化活性的变化,该试验通过响应面分析法确定发酵桑叶茶在发酵温度、发酵时间和黑曲霉接种量3种变量条件下的最佳工艺条件,并测定发酵桑叶茶生物活性物质含量及其抗氧化性。结果表明,最佳工艺条件为发酵时间5 d 16 h,发酵温度30℃,接种量16.55%,此条件下所制发酵桑叶茶感官评分高达90分,且其总黄酮、总多糖、多酚、游离氨基酸、芦丁、槲皮素含量比桑叶绿茶分别升高了14.39%、12.67%、2.90%、3.46%、81.13%、19.35%,还检测到了含量7.55%±0.37%的茶褐素。此外,1/1000(g/mL)浓度下发酵桑叶茶对羟基自由基、DPPH自由基、超氧自由基的清除率和对二价铁离子的螯合率分别是桑叶绿茶的1.16倍、1.07倍、1.06倍和0.82倍,该研究结果为今后桑叶的进一步开发与应用提供理论基础和参考。
文摘采用烘制和烤制2种不同加工工艺制备黄精茶,并对其质构特性、挥发性成分、感官品质及抗氧化作用进行对比分析。结果表明,不同加工工艺对黄精茶色泽影响较大,但对其复水比、皱缩比及微观组织结构等质构特性影响不显著。固相微萃取/气相色谱-质谱联用(solid phase microextraction combined with gas chromatography-mass spectrometry, SPME/GC-MS)分析结果表明,烘制和烤制黄精茶的主要呈香物质相似但含量不同,以烷类及芳香族化合物为主,而苯乙醇、甲基丁香酚、桉叶油醇可能是黄精茶特征性风味物质。感官品质以烘制黄精茶相对较好。与烤制黄精茶相比,烘制黄精茶更好地保留了总酚、总黄酮等生物活性物质,并具有更为显著的ABTS阳离子自由基、DPPH自由基清除作用。该研究为黄精的有效开发与利用提供了理论参考。
