Free radical scavenging activities and bioactive substances of Jerusalem artichoke (Helianthus tuberosus L.) leaves

The total phenolic content and radical scavenging activities of Jerusalem artichoke (Helianthus tuberosus L.) leaves were investigated. Results indicated that the ethyl acetate fraction contained the highest total phenolic content (266.69 ± 2.51 mg GAE/g dry extract) accompanied with strongest free radical scavenging abilities. Following an in vitro radical scavenging activity-guide fractionation procedure, six phenolic compounds which strongly quenched free radicals were separated from ethyl acetate fraction. Among them, 3-O-caffeoylquinic acid and 1,5-dicaffeoylquinic acid played a dominant role due to their strong free radical scavenging abilities and their high contents. The content of 3-O-caffeoylquinic acid in n-butanol fraction was 74.58 ± 1.05 mg/g, while 1,5-dicaffeoylquinic acid in ethyl acetate fraction was 104.51 ± 2.86 mg/g. The results imply that the leaves of Jerusalem artichoke might be a potential source of natural antioxidants.     

Enzymatic browning and after-cooking darkening of Jerusalem artichoke tubers (Helianthus tuberosus L.)

Jerusalem artichoke tubers (Helianthus tuberosus L.) undergo enzymatic browning when peeled or cut, and turn grey after boiling, due to after-cooking darkening reactions between iron and phenolic acids. In an attempt to reveal the components responsible for these discolouration reactions, sensory evaluation and instrumental colour measurements were related to contents of total phenolics, phenolic acids, organic acids and iron in three varieties of raw and boiled Jerusalem artichoke tubers harvested in the autumn and the spring. No differences were found between varieties in sensory evaluated enzymatic browning, but Rema and Draga had higher scores than Mari in after-cooking darkening. Jerusalem artichoke tubers had higher contents of total phenolics, phenolic acids and citric acid in the autumn and low contents in the spring, while it was the opposite for malic acid. None of the chemical parameters investigated could explain the discolouration of the Jerusalem artichoke tubers.     

菊芋渣蛋白的提取及功能性质研究

采用超声波辅助碱法提取菊芋渣蛋白,并测定其部分功能特性。通过正交实验确定最佳提取工艺,实验结果表明,菊芋渣蛋白最佳提取条件为:p H13.5,料液比1∶40(mg/m L),超声时间50min,超声温度60℃,在此条件下提取率可达71.2%±0.3%。菊芋渣分离蛋白的等电点在4.0左右,当p H=9.0时乳化能力可达80%,蛋白浓度4%时起泡性最好,70℃时溶解性最好。      

Feeding Jerusalem artichoke (Helianthus tuberosus) to pigs

Weaned pigs were fed diets with added Jerusalem artichoke for 28 days. In a first trial, the pigs received raw tubers in addition to their normal ration. In a second trial, the pigs received dried Jerusalem artichoke (10–60 g kg^-1) in the diet. Pigs eating the raw tuber had significantly increased body weight gains due to the consumption of the raw tuber, but significantly decreased feed efficiency. Adding dried Jerusalem artichoke to the diet significantly increased weight gains. Feed efficiency was improved, but not significantly. Faecal valeric acid concentration was significantly increased in animals eating Jerusalem artichoke.     

菊芋菊糖的提取与纯化

重点研究了菊芋菊糖的提取与纯化。选择提取温度、提取时间、料液比、提取次数进行单因素实验,确定条件范围,再采用正交实验优化提取条件,得到菊芋菊糖提取最佳工艺条件为温度70℃、提取时间90min、料液比1∶15,菊糖提取率可达90.76%。提取液80℃保温1h菊糖保留率高达95.88%且除去60%以上蛋白质。经过D218离子交换树脂脱色处理,菊糖液色泽澄清,呈白色,蛋白质基本除去。最后冷冻干燥得产品,总糖含量达98%以上,其中菊糖含量为96.23%。     

Sensory quality and appropriateness of raw and boiled Jerusalem artichoke tubers (Helianthus tuberosus L.)

BACKGROUND: The aim of the present study was to investigate the sensory attributes, dry matter and sugar content of five varieties of Jerusalem artichoke tubers and their relation to the appropriateness of the tubers for raw and boiled preparation. RESULTS: Sensory evaluation of raw and boiled Jerusalem artichoke tubers was performed by a trained sensory panel and a semi‐trained consumer panel of 49 participants, who also evaluated the appropriateness of the tubers for raw and boiled preparation. The appropriateness of raw Jerusalem artichoke tubers was related to Jerusalem artichoke flavour, green nut flavour, sweetness and colour intensity, whereas the appropriateness of boiled tubers was related to celeriac aroma, sweet aroma, sweetness and colour intensity. In both preparations the variety Dwarf stood out from the others by being the least appropriate tuber. CONCLUSION: A few sensory attributes can be used as predictors of the appropriateness of Jerusalem artichoke tubers for raw and boiled consumption. Knowledge on the quality of raw and boiled Jerusalem artichoke tubers can be used to inform consumers on the right choice of raw material and thereby increase the consumption of the vegetable. © 2012 Society of Chemical Industry     

菊芋渣酶解法的二次提糖工艺

利用菊粉酶酶解法提取菊芋渣中的单糖,采用单因素实验和正交实验研究提取工艺条件,优化的提取条件为:pH值4.6、酶加量25 U/g、提取温度60℃、料液比1∶25、提取时间6 h。在此条件下,单糖平均提取率为82.67%。采用薄层色谱法对酶解产物进行成分分析,结果表明,酶解液中主要含有果糖和葡萄糖两种单糖。经DNS法测定,酶解1 g底物,产物中果糖和葡萄糖的含量分别为135.9 mg和84.9 mg,两种单糖的比例为1.6∶1。     

菊芋渣的组分分析及其酶解糖化条件研究

探索了菊芋渣酶解糖化制备可发酵糖的工艺条件。详细考查了纤维素酶、木聚糖酶和淀粉酶以不同组合形式（单一或复合酶水解）进行酶解对其酶解得率的影响,并结合扫描电镜（SEM）和X-衍射（XRD）技术考察酶解前后的菊芋渣结构变化,筛选适宜的酶解方案。结果表明,菊芋渣中纤维素、半纤维素和淀粉含量分别为22.54%、18.00%、20.49%,总碳水化合物含量高达61%以上,是制备葡萄糖等可发酵糖的良好原料。酶解实验结果表明,依次添加纤维素酶、淀粉酶和木聚糖酶（方案Ⅰ）的分步水解法酶解得率最高为75.33%,3种酶添加量分别为7200、12000和10000 U/g,酶解时间依次为3.5、3.5和3.0 h。SEM和XRD表征结果发现,原先致密的菊芋渣表面微观结构经酶解作用后出现许多孔洞和裂痕,沟壑明显,且方案Ⅰ的酶解残渣相对结晶指数最高,说明纤维素结晶区也发生了降解。总之,菊芋渣中碳水化合物含量丰富,复合酶解后能制得微生物可发酵糖,为下游乙醇发酵奠定物质基础。      

酒曲在菊芋发酵生产乙醇中的应用

菊芋是一种极具潜力的乙醇发酵原料,利用安琪酿酒曲具有发酵菊芋生产乙醇的能力,研究安琪酿酒曲应用于菊芋发酵生产乙醇的工艺参数.确定最佳工艺条件为以1:4(w/v)的料液比调浆,32℃发酵60h.在此工艺条件下酒精度可达12.1%vol,酒精产率达38.19%.从试验结果可推论,利用安琪酿酒曲发酵菊芋生产乙醇是可行的.     

发酵条件对一步法发酵菊芋生产乙醇的影响

使用产菊粉酶的酿酒酵母可实现一步法发酵菊芋生产乙醇.该试验以菊芋汁为发酵培养基,研究了起始糖浓度、无机盐、温度、种子培养基、接种量和氮源对高菊粉酶活酿酒酵母Y05-步发酵菊粉生成乙醇的影响.试验结果表明:(1)菊芋汁中最适起始总糖浓度为250g/L.菊芋汁含有的较多无机盐对乙醇发酵不但没有抑制作用,反而有促进作用;(2)最适乙醇发酵温度为37℃;(3)种子培养基中使用菊粉做为碳源有利于酿酒酵母Y05产生较多菊粉酶,进而促进其乙醇发酵;(4)最适乙醇发酵接种量为15％;(5)尽管菊芋汁是一个良好乙醇发酵培养基,但补加氮源仍是必要的.补加5.0g/L玉米浆可显著酿酒酵母Y05的提高总糖利用率、最终乙醇浓度和乙醇得率.     

黑菊芋中5-羟甲基糠醛制备及含量分析

高效液相色谱法(HPLC)测定5-羟甲基糠醛的含量。正交试验L9(34)确定黑菊芋中5-HMF的最佳制备方法,同时对不同保存时间黑菊芋(0,3,6和18 m)、黑蒜、乌酸酶,黑咖啡等几种食品中5-HMF含量进行分析。结果表明,最佳条件为温度40℃、料液比1︰8(g/mL),提取时间5 h;黑菊芋5-HMF含量随保存时间降低,且显著低于咖啡。研究为黑菊芋食品安全性评价提供实验依据。     

菊芋低聚果糖抗运动疲劳作用研究

目的 探究菊芋低聚果糖抗运动疲劳作用.方法 利用C2C12细胞和SD大鼠作为研究对象,通过大鼠跑步耐力试验,测定不同剂量组和对照组糖原、血清氨、无机磷酸盐、乳酸含量,以及肌肉乳酸脱氢酶(lactate dehydrogenase,LDH)和血清肌酸激酶(creatine kinase,CK)活性、血浆丙二醛(malon...     

菊芋提取液除杂工艺的研究

采用石灰充碳法对菊芋提取液进行除杂,通过考虑加石灰量、充CO2 量及操作温度对蛋白质去除率的影响,并对提取液中的Ca2+ 浓度进行控制,得出最优化条件：加石灰至pH13.4、充CO2 至pH6.8、操作温度80℃。结果表明：最终蛋白质去除率为81.6%,菊粉损失为3.4%(90% 以上是果糖),显示了该法在较小菊粉损失的前提下,对去除菊芋提取液中还原糖成分有显著的效果。     

响应面法优化菊芋渣中果胶的提取工艺及产品性质分析

应用响应面分析法对菊芋渣中果胶的提取工艺进行优化。首先研究了不同的提取剂种类（盐酸、硫酸、亚硫酸、磷酸）对果胶得率的影响,结果表明磷酸提取效果最佳。在单因素试验的基础上,以磷酸为提取剂,采用Box-Behnken试验设计方案,以提取温度、pH值、提取时间、液料比为影响因素,以果胶得率为响应值,通过响应面分析法得到菊芋渣果胶的最佳提取条件为提取温度100 ℃、pH 1.52、提取时间63.62 min、液料比44.4∶1（mL/g）,此条件下果胶的最高得率为18.76%。在最优条件下进行验证实验,实际提取结果为（18.52±0.9）%,这与模型预测值吻合,说明建立的模型可行。测定最优条件下获得果胶样品的红外光谱结构并进行了解析,分析果胶产品的性质发现,各项指标均符合GB 25533-2010《食品添加剂：果胶》的要求。     

乳酸菌发酵菊芋汁及其风味的研究

对不同品种和产地的菊芋主要成分进行了测定,并利用乳酸菌对菊芋汁进行发酵,研究了不同乳酸菌在菊芋汁中的生长规律、低温存活性及发酵菊芋汁中主要风味物质。结果表明,4种乳酸菌在菊芋汁中均生长良好,最高活菌数可达到109CFU/mL;菊芋汁经乳酸菌发酵后具有良好风味,其风味的差异与发酵菌种有关;发酵菊芋汁中乳酸菌在4℃低温贮藏过程中具有较好的低温存活性,4周后活菌数保持在108CFU/mL。菊芋汁适用于开发成新的功能性乳酸菌饮料。     

响应面分析法优化菊芋渣中蛋白的提取工艺

以菊芋渣为研究对象,用蛋白质提取率作为衡量提取工艺的指标。在单因素实验基础上,选取pH、提取温度、提取时间为自变量,蛋白提取率为响应值,利用Box-Benhnken中心组合设计原理和响应面分析法,研究各自变量及其交互作用对提取率的影响,模拟得到二次多项式回归方程的预测模型,在固液比为1:30(g/mL)的条件下,确定最佳提取条件为pH14.0、提取温度82℃、提取时间2h。在此条件下,平均蛋白提取率为22.7747mg/g。与理论预测值23.3187mg/g相比,其相对误差约为2.33%。说明通过响应面优化后得出的回归方程具有一定的实践指导意义。     

微波辅助提取红菊芋色素及稳定性研究

采用微波辅助提取法对红菊芋色素的提取工艺进行了研究。紫外光谱扫描确定在pH值0.98的乙醇体系中,红菊芋色素的最大吸收波长为533 nm。单因素和正交试验结果表明,乙醇浓度、料液比、微波提取功率和对红菊芋色素提取率有显著影响。优化的提取工艺为,提取溶剂2%HC l-60%乙醇-水溶液,料液比(g∶mL)为1∶30,微波功率480 W,提取时间50 s,其提取率达29.84 mg/g。红菊芋色素在自然光下稳定性较好,温度超过60℃,热稳定性较差。     

菊芋的贮藏与果聚糖提取研究

对菊芋块茎贮藏条件、果聚糖的提取与提取液的精制进行了研究.结果:收获后的菊芋块茎在室温存放时间不宜超过10 d,在5℃条件下存放不宜超过20d,将菊芋块茎清洗后装入聚乙烯袋中,置于1℃的条件下存放能长期贮存;以水为提取剂,提取果聚糖的工艺条件为:水:料为3:1,水温为100℃,时间为20min,次数为3,果聚糖的得率较高;用Ca(OH)2将提取汁的pH值调到11,然后用H2PO4将其pH值调回到8的澄清效果最好;通过离子交换树脂处理后能获得色泽、风味较好的提取汁.     

响应面法优化从菊芋中浸提菊粉的工艺条件研究

温度、浸提时间、液固比和pH值是影响菊粉浸提得率的几个重要因素.本实验通过响应面法分析,在自然pH值、液固比为10.56:1(V/W)、76.7℃下热水浸提20min,菊粉的提取率可以达到最大值83.6%.