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     

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.     

Scale‐up batch fermentation of bioethanol production from the dry powder of Jerusalem artichoke (Helianthus tuberosus L.) tubers by recombinant Saccharomyces cerevisiae

This study is a first exploration of industrial bioethanol production from the dry powder of Jerusalem artichoke (Helianthus tuberosus L.) tubers by recombinant S. cerevisiae 6525. Scale‐up fermentation of bioethanol production from the dry powder of Jerusalem artichoke tubers by recombinant Saccharomyces cerevisiae 6525 was carried out at the scale of 50 and 500 L agitating fermentors. For the 50 L fermentor, 85.67 g/L of ethanol was obtained within 72 h of fermentation, and the ethanol yield was 90.1%. For the 500 L fermentor, the highest ethanol concentration of 77.00 g/L was achieved at 84 h, and the ethanol yield was 81.01%. These results indicated that a relatively high yield of ethanol could also be obtained from a scaled‐up fermentation of Jerusalem artichoke powder. Thus, it may be feasible to use a Jerusalem artichoke tuber feedstock to carry out ethanol fermentations using the recombinant S. cerevisiae 6525 for industrial production. Copyright © 2016 The Institute of Brewing & Distilling     

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%。     

Sorption Isotherms and Drying Rates of Jerusalem Artichoke (Helianthus tuberosus L.)

Moisture sorption properties and drying behavior of Jerusalem artichoke roots were investigated. Sorption isotherms of dehydrated and freeze-dried material, its water insoluble components, fructose, glucose and sucrose were determined at 10, 25 and/or 40°C. Adsorption-desorption isotherms indicated a combination of sorption by soluble sugars, in the crystalline, amorphous and aqueous solution state, and sorption by polymeric material such as cellulose, inulin and protein. In drying experiments conducted at 50, 65, 80, and 95°C, and also at 65°C and four air velocities and four bed depths, it was found that temperature and drier load conditions are of critical importance to drying behavior, drying time and finished product color. Increasing the air velocity from 2.0 to 4.2 m/set, at a temperature of 65°C and a bed depth of 10.5 cm, did not change the rate for drying 1 cm cubes.     

Changes in extractability and antioxidant activity of Jerusalem artichoke (Helianthus tuberosus L.) tubers by various high hydrostatic pressure treatments

This study investigated changes in the extraction characteristics of Jerusalem artichoke (Helianthus tuberosus L.) tubers (JA) using high hydrostatic pressure (HHP) treatment alone and in combination with enzymes and/or fermentation. HHP treatment of JA increased the soluble solid content and decreased the turbidity compared to the control group that received hot-water extraction. This indicates improved extractability of JA by HHP treatment alone or in combination. Combined HHP treatment with enzymes increased the contents of non-reducing sugars, fructooligosaccharide (FOS), and free amino acids in the extracts compared to those of control, thus activating browning reaction. Extraction of fermented JA by HHP treatment with or without enzyme showed increased polyphenol content as well as improved 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and superoxide dismutase (SOD) like activity compared to the control group. Taken together, HHP treatment of fermented JA with enzymes significantly improved the extractability of bioactive molecules such as phenolics and FOS compared to conventional water extraction or HHP treatment alone. Our results provide useful information for the improvement of raw material extraction by HHP treatment in combination.     

In vitro prebiotic activity of inulin-rich carbohydrates extracted from Jerusalem artichoke (Helianthus tuberosus L.) tubers at different storage times by Lactobacillus paracasei

In the present work the in vitro prebiotic activity of inulin-rich carbohydrates using Lactobacillus paracasei as probiotic microorganism was determined. With this purpose, inulin-rich carbohydrates samples from Jerusalem artichoke tubers stored at 4–5 °C during different times along an overall period of 8 months were extracted. Extraction yield, inulin content and average polymerization degree of inulin-rich carbohydrates samples were also determined. For all samples, extraction yield and inulin content decreased with storage time. In particular, inulin content exhibited values within the range of commercial food grade inulin (≥ 85%). Average polymerization degree values decreased with storage time ranging from 12.1 to 8.3. The in vitro prebiotic activity of inulin-rich carbohydrates samples was assessed using a prebiotic activity score which considered the growing ratio relative to glucose of L. paracasei as well as of the enteric bacteria Escherichia coli when such carbohydrates were used as C source. Inulin-rich carbohydrates extracted from tubers cold-stored during 4 months showed the highest prebiotic activity score, even higher than the corresponding to a commercial food grade inulin, indicating that this sample should be used as a prebiotic food ingredient, representing a potential alternative to the available commercial inulin obtained from chicory roots.     

菊芋中菊粉提取与护色工艺的研究

采用热水浸提法从菊芋中提取菊粉。在单因素实验的基础上,通过正交试验对热水提取菊粉的工艺参数进行优选,试验结果表明:在料液比为1∶11,提取温度为90℃,提取时间为80min,原料粉碎粒度为10mm,提取两遍,菊粉提取率达98%。并通过实验初步确定提取时添加0.75%的抗坏血酸钠为护色剂对料液的护色效果最佳。     

Norwegian‐grown Jerusalem artichoke (Helianthus tuberosus L.): morphology and content of sugars and fructo‐oligosaccharides in stems and tubers

BACKGROUND: Two field trials growing Jerusalem artichoke (Helianthus tuberosus L.) are discussed. Twenty genetic variants were compared in order to find genotypes suitable for Norwegian production. A second trial investigated the above‐ground part of early and late variants. RESULTS: The highest yield (28.7 t ha^?1) and highest amount of tubers per plant was obtained in early variants, e.g. the white Tysnes gave 1.72 kg tubers plant^?1. Early variants had a markedly lower portion of smooth tubers. Late variants gave the most preferable tuber shape, but low yield. Only a weak correlation was found between dry matter content and total content of fructo‐oligosaccharides (FOS) (r = 0.255) in the tubers. The mean content of FOS including sucrose through all variants was found to be 116 g kg^?1 fresh weight (FW) or 550 g kg^?1 dry weight (DW). The average chain length of FOS in the tubers was found to be DP3.9. There was no difference in tuber FOS content between early and late variants. The highest above‐ground amount biomass was found for the late variants when harvested in September. The content of soluble carbohydrates was found to be highest in stalks in August (sucrose and FOS major compounds). CONCLUSION: Early variants give the highest tuber yield under Norwegian growing conditions. Late variants give highest above‐ground biomass. Copyright © 2010 Society of Chemical Industry     

菊芋中提取菊粉的纯化工艺研究

采用石灰乳-磷酸法除杂和脱色剂脱色,对菊芋菊粉粗提液进行纯化研究。结果表明:石灰乳-磷酸法对菊粉粗提液除杂的最佳工艺条件为:pH12.0,温度60℃,时间10min,在此最佳条件下体系的透光率从46.5%上升到87.3%;比较几种脱色剂的脱色效果,活性炭的脱色效果最好;当活性炭用量为0.7g/100mL(除杂液),脱色温度80℃,脱色时间30min,透光率高达96.7%;当活性炭用量为0.3g/100mL(除杂液),脱色温度40℃,脱色时间10min,菊粉损失率仅为4.05%。     

Physicochemical characteristics of inulins obtained from Jerusalem artichoke (Helianthus tuberosus L.)

The physicochemical characteristics (thermal stability, glass transition temperature and degree of crystallinity) of inulins, obtained from the tubers of four varieties Jerusalem artichoke (Helianthus tuberosus L.) grown in Bulgaria—Energina, Verona, Topstar and Spindel, were investigated. The inulins obtained had molecular weight from 4,882 to 5,600 Da (degree of polymerization around 30 fructose units). The experimental data from differential scanning calorimetry showed that the glass transition temperature of inulins is between 51 °C and 55 °C. It was found that the first transition (due to evaporation of the unbound water) starts from 77 to 80 °C. The second transition phase started between 152 and 158 °C, and it determines the limit of inulin thermal stability. The data from differential thermal analysis confirmed the results of differential scanning calorimetry with slight differences in the starting temperatures and durations of the phase transitions. X-ray analysis showed that the degree of crystallinity of inulins is very low (except for Spindel inulin—21%).     

菊芋菊糖粗提液的微生物除杂

通过对11株酵母菌产的菊粉酶活力进行测定与分析,筛选出1株内切酶活性较低的菌株S-2;对采用菌株S-2脱除菊芋提取液中还原糖和蛋白质的影响因素进行了优化,结果表明,在培养温度30℃、时间50 h、摇瓶转速160 r/min条件下,菌株S-2对还原糖和蛋白质的脱除率分别为92.4%和92.9%,菊糖损失率为2.86%,除杂效果良好;对S-2菌株通过构建进化树进行系统分析,鉴定为酿酒酵母。     

Optimisation of inulin extraction from globe artichoke (Cynara cardunculus L. subsp. scolymus (L.) Hegi.) by electromagnetic induction heating process

In this study, a D‐optimal design was used to optimise the extraction process conditions of inulin with a high degree of polymerisation from Globe artichoke heart (Cynara cardunculus L. subsp. scolymus (L.) Hegi.), using electromagnetic induction heating (EMIH) as a new extraction process. Four factors were simultaneously studied which were the extraction temperature (55–90 °C), the extraction time (30–120 min), the weight ratio (plant material dry weight/volume of distilled water: 5–10%) and the mode of heating (conventional or electromagnetic induction heating). It was found that the second‐order polynomial models developed by the response surface methodology (RSM) describe adequately the relationship between the factors and responses (extraction yield, viscosity and solubility of inulin). The optimum extraction conditions that led to a maximal extraction yield (45.98%) and an optimal viscosity (3.25 mL g^?1) of extracted inulin are temperature of 89.49 °C, extraction time of 120 min and a 5.01% of weight ratio using EIMH process. Fourier Transform InfraRed spectroscopy spectrum of the extracted inulin was identical to that of the native inulin. The analysis of the extract by thin‐layer chromatography confirms the absence of pectin in the final product, as well as the X‐ray diffraction analysis exhibits a semi‐crystalline structure of the biopolymer.     

A simplified spectrophotometric method for the determination of inulin in Jerusalem artichoke (<Emphasis Type="Italic">Helianthus tuberosus</Emphasis> L.) tubers

A simple spectrophotometric method was developed for the analysis of inulin in Jerusalem artichoke tubers. The inulin was extracted from the artichoke tuber samples using accelerated solvent extraction method, before subsequent hydrolysis in acid condition. The hydrolysates were then analyzed for fructose using spectrophotometry. The spectrophotometric method is based on oxidation of fructose by periodate and evaluation of the remaining periodate by measuring the absorbance at 350 nm of the tri-iodide complex formed, upon addition of potassium iodide. The optimum conditions for the detection of fructose were 0.1 mmol L⁻¹ periodate and 1.5 mmol L⁻¹ potassium iodide at pH 6.0. The proposed method was validated for its analytical performance parameters including accuracy, precision, and recovery. The method was applied to the determination of inulin in ten varieties of Jerusalem artichoke grown in the northeastern part of Thailand. The inulin content in the samples was found to be in the range of 63–75.5% dry weight, and the degree of polymerization was in the range of 14–20. The inulin contents obtained from the proposed spectrophotometry were not significantly different (p = 0.05) from those obtained from high-performance anion-exchange chromatography coupled with pulsed amperometric detection. The results indicated that the present spectrophotometric method can be used as an alternative to chromatographic analysis for the determination of inulin in plant samples.