产自大丽花块极的果糖浆

高果糖浆是一种新型甜味剂，由于它具有保健性，易加工性和高甜度，发达国家在食品工业已经广泛用它代替精炼砂糖。利用大丽花块根为原料生产出的果糖浆，其果糖含量可高达95％（干基）以上，并且工艺简单。大丽花属于菊科植物。作为一种观赏植物，全国各地均有种植。菊糖是大丽花中的贮藏多糖，大量存在于大丽花的块根中。菊糖是由D－呋喃果糖以β-1，2甙键脱水聚合而成的果聚糖。每个菊糖分子中约占30－35个果糖残基线型结构。分子链的末端有一葡萄糖残基。每个菊糖分子中葡萄糖含量约占3％。菊糖在酶或酸的作用下很易水解生成果糖。本试验中利用菊糖的一性质生产高纯果糖浆。     

产自大丽花块根的果糖浆

产自大丽花块根的果糖浆周永国胡永利班景昭（河北农业技术师范学院，昌黎，０６６６００）高果糖浆是一种新型甜味剂，由于它具有保健性、易加工性和高甜度，发达国家在食品工业中已经广泛用它代替精炼砂糖。利用大丽花块根为原料生产出的果糖浆，其果糖含量可高达９５％...     

结晶纯果糖

虽然学了有机化学就知道蔗糖是由葡萄糖和果糖所组成的双糖，蔗糖也容易水解成它的组分。食品科学家们又发现纯果糖的甜度大于蔗糖，而且具有极好的代谢特性，被认为是优质甜味剂。然而直到70年代中期，随着糖化学的进步，才在美国实现了纯果糖的商业化生产。最早，人们曾试图利用存在于大丽花、耶路撒冷菊等植物的球根中的菊糖，通过有控制的水解，分裂β－（α→1）配糖键，使在这种果聚糖（菊糖）中占绝大多数的峡哺果糖转变成更稳定的吡哺果糖异构物。但是，虽经努力，所得的果糖因价格无竞争力，不能大量提供给食品加工作为配料。60年…     

不同熟化方式对食用型甘薯中可溶性糖分组成的影响

为了探究不同熟化方式对甘薯块根中可溶性糖分组成及含量的影响,采用80%的乙醇水溶液低温振荡提取、离子色谱—脉冲安培法同时检测提取液中多种可溶性糖分的方法,测定了生薯和蒸制、烤制、微波三种熟化方式下甘薯块根中可溶性糖分组成及其含量,并以生薯样品为对照,分析了不同熟化方式对食用型甘薯可溶性糖组成及其变化特征。结果表明：通过本方法在提取液中共检测出半乳糖、甘露糖、葡萄糖、果糖、蔗糖、麦芽糖、水苏糖共7种可溶性糖组分;不同熟化方式下以烤制样品中可溶性糖的总量最高,达410.4g/kg,生薯粉中可溶性糖总量最低,仅占到烤制样品中可溶性总糖的29.6%,不同处理对可溶性糖组分总量影响的顺序为烤制>微波>蒸制>生薯;生薯中占比最大的三种糖分别是葡萄糖、果糖和蔗糖,三种糖分占可溶性糖组分总量的95%以上;熟化后样品中占比最大的为麦芽糖,其次为蔗糖,烤制样品中麦芽糖占可溶性糖组分总量的50%以上。     

当心果糖造成“甜蜜危害”

什么是果糖 果糖是水果和花蜜中的一种糖分。在各种天然糖中，果糖的甜度最高，其甜度大约是蔗糖的1．8倍。在蜂蜜中约含49％的果糖。     

自然界中的低聚果糖——丰富的来源,多样的结构

低聚果糖,又名果寡糖、果糖低聚糖或果聚糖,一般通过β(2→1)糖苷键或β(2→6)糖苷键在蔗糖分子的果糖基或葡萄糖基上连接1-3个果糖而成的蔗果三糖、蔗果四糖、蔗果五糖及其混合物.低聚果糖是公认典型的益生元,也是一种水溶性膳食纤维,天然存在于自然界的36000种植物中.     

俄开发制取高纯度果糖新工艺

俄罗斯专家利用多黏芽孢杆菌的特性，研究开发出一种制取高纯度果糖新工艺。通常采用的酶解法只能将50％的含糖原料转化为果糖，所制得的果糖中仍含有一定量的葡萄糖。为改进果糖制取工艺，俄专家对果糖原料和制取过程中所需的生物酶进行研究，发现菊科草本植物中含大量果糖聚合物一菊糖。在菊糖酶的分解作用下，菊糖被转化为果糖。     

国外动态

日本参松有限公司是生产液体葡萄糖和果糖的.最近在研究和试验过程中找到一种提高果糖纯度的方法.在此基础上,他们进一步研制成功一种成本低、甜度好、含果糖55%的液体糖,并已开始出售,主要用于饮料行业.这种液体糖的pH值为4.5,含水分25%,糖分75%,其中果糖、葡萄糖和其它糖分别占整个糖分的55%、40%和5%.     

蔗糖深加工的优良产品——低聚果糖

低聚果糖（蔗果三糖族低聚糖），其分子式为；G－F－Fn；n＝1～3（G为葡萄糖，F为果糖），它是由蔗糖和1～3个果糖基通过β－2－1键与蔗糖中的果糖基结合而成的蔗果三糖、蔗果四糖和蔗果五糖及其混合物。低聚果糖是一种以蔗糖为原料经现代生物工程技术生产而成的新一代保健食品     

贮藏温度对雪莲果块根品质的影响

本文研究了不同贮藏温度对雪莲果块根中总糖、低聚果糖、蛋白质可溶性固形物含量及果实硬度的影响,同时分析了多酚氧化酶、过氧化氢酶在不同贮藏温度下随时间的变化关系。结果显示,在贮藏过程中,贮藏温度越高,总糖、蛋白质含量降幅越大,降速越快,尤其是在前7d,而0℃和4℃的贮藏效果则相对较好,综合硬度和低聚果糖含量来考虑,4℃下贮藏效果较好。多酚氧化酶和过氧化物酶在4个贮藏温度下均呈现先升后降的趋势,且温度越高,酶活性峰值越早出现。     

Inulin Potential for Enzymatic Obtaining of Prebiotic Oligosaccharides

Oligosaccharides have been marketed since the 80s as low-calorie agents and recently have gained interest in the pharmaceutical and food industry as functional sweeteners and prebiotic enriching population of Bifidobacteria. Currently, they have an approximated value of $200 per kg and recently, inulin has been proposed as a feedstock for production of oligosaccharides through selective hydrolysis by action of endoinulinase. High optimum temperature (60°C) and thermostability are two important criteria that determine suitability of this enzyme for industrial applications as well as enzyme cost, a major limiting factor. Significant reduction in cost can be achieved by employing low-value and abundant inulin-rich plants as Jerusalem artichoke, dahlia, yacon, garlic, and onion, among others. In general, the early harvested tubers of these plants contain a greater amount of highly polymerized sugar fractions, which offer more industrial value than late-harvested tubers or those after storage. Also, development of recombinant microorganisms could be useful to reduce the cost of enzyme technology for large-scale production of oligosaccharides. In the case of fungal inulinases, several studies of cloning and modification have been made to achieve greater efficiency. The present paper reviews inulin from vegetable sources as feedstock for oligosaccharides production through the action of inulinases, the impact of polymerization degree of inulin and its availability, and some strategies to increase oligosaccharide production.     

Inulin and Sugar Contents in Helianthus tuberosus and Cichorium intybus Tubers: Effect of Postharvest Storage Temperature

ABSTRACT: Inulin, sucrose, fructose, and glucose contents in tubers of Helianthus tuberosus (Jerusalem artichoke) and Cichorium intybus stored at different temperatures (-18, 4, and 18 °C) after harvesting were followed. Inulin content in both tubers decreased during storage. In C. intybus this decrease was associated with increases in glucose and fructose contents. In H. tuberosus the fructan fraction having molecular weight between 800 and 1200 increased after sucrose reached its maximum content [1.3–10⁻¹ g(g d.w.)⁻¹] in tubers stored at 4 °C. Fructose-to-glucose ratio was followed in H. tuberosus tubers harvested at different times; samples from plants subjected to different fertilization treatments were used. This parameter can be used for choosing the harvest date since it is related to the disappearance of the fructan fraction having molecular weight higher than 1200.     

Physicochemical changes occurring during post-harvest hardening of trifoliate yam (Dioscorea dumetorum) tubers

Processing of Dioscorea dumetorum tubers into flour could be a means of adding a longer-term value to this tropical plant with a high nutritional potential but which presents a post-harvest hardening problem. This study was carried out in order to investigate the effect of storage under prevailing tropical ambient conditions (19–28 °C, RH 60–85%) for 56 days on the physicochemical characteristics of flours produced from hardened tubers. With the exception of bulk density, the results showed that all the physicochemical properties measured (water absorption capacity, oil absorption capacity, water solubility index, hydrophilic–lipophilic index, swelling capacity and least gelatinising concentration) were significantly influenced by tuber storage time (P<0.05). In general, the physicochemical indices increased with storage in at least two phases, from days 2 to 21 and from days 28 to 56. Since sprouting of most tubers was observed after 28 days of storage, the results suggest that post-harvest hardening and sprouting influence the above-mentioned indices of flours produced from D. dumetorum tubers.     

The Development and Properties of the Tuber of the Potato (Solanum tuberosum) Part I: Variability of Tubers

A series of studies that show the great variability of tubers between plants and within one plant. “Twinning”, the tendency for a plant to bear several tubers of similar size, is introduced, and a relationship between size and specific gravity of tubers is shown briefly.     

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.     

A survey of acrylamide precursors in Irish ware potatoes and acrylamide levels in French fries

Reducing sugars (glucose and fructose) and asparagine levels in three varieties of Irish ware potatoes (Rooster, Record and Oilean) on sale in a local supermarket were monitored over an 11-month period. Samples were processed into French fries using conditions similar to those used for home preparation of fries and acrylamide levels in a selection of samples were measured. A wide range of total reducing sugar levels (fructose+glucose) were observed over the course of the study with values ranging from 152-12,286, 301-8812 and 279-7881 μg/g FW for the Rooster, Record and Oilean varieties, respectively. This resulted in high levels of acrylamide in some samples (up to 2970 μg/kg). In comparison to reducing sugars, asparagine contents were relatively constant for the three varieties and no particular trend in asparagine levels was noted. Both fructose and glucose contents of the tubers were positively correlated with acrylamide content (r=0.809, 0.776, respectively, P<0.001). A negative relationship between Hunter L values and acrylamide content of the French fries was observed (r=−0.712, P<0.001) indicating that L values could serve as a convenient and reliable indicator of acrylamide levels in French fries.     

Inulinhaltige Pflanzen als Rohstoffquelle. Biochemische und pflanzenphysiologische Aspekte

Inulin Containing Plants, Alternative Resources. Biochemical and Plant Physiological Aspects. First the appearance and the physico-chemical properties of inulin are discussed and the classical and modern methods of the determination of inulin are compared. For the determination of the distribution and composition of inulin a HPLC- and a GPC-method are presented. Using these methods different carbohydrate distribution patterns are got by analyzing different inulin containing plants. The utilization of inulins for industrial production is narrowly connected with their molecular weight distribution. Thus inulin is split by invertase only very slowly whereas the inulooligosaccharides are split relative quickly. For the production of fructose long-chain inulins are advantageous because only little of the cristallization inhibitor glucose is got after hydrolysis. For fermentation short-chain oligosaccharides, that are easily fermentated by microorganisms, are favourable. As an example for high molecular weight inulins dahlia and chicory inulin are named. Jerusalem artichoke inulin however is composed of a high portion of low molecular weight oligosaccharides that is suited for the production of alcohol, especially when harvested at a late date (late autumn or spring).     

Sprout inhibition of potatoes with soft‐electron (low‐energy electron beams)

The surfaces of potatoes were irradiated with electrons of different energy levels, and the effects on sprouting were investigated. Electrons at 270 keV or higher effectively inhibited sprouting of four cultivars of potatoes, cvs Danshaku, Hokkaikogane, Toyoshiro and May Queen, even after storage at 23 °C for 4 months. Sugar contents in tubers treated with 270‐keV electrons were lower after storage for 3 months than their levels before electron treatment. The levels of glucose, fructose and sucrose were significantly lower in the tubers treated with 270‐keV electrons than in low temperature (5 °C)‐stored tubers. The results indicate the potential of low energy electron treatment for the shelf‐life extension of potatoes as an alternative to treatments with gamma‐rays or chemicals. Copyright © 2004 Society of Chemical Industry     

The effect of the time and mode of application of gibberellic acid and inhibitors of gibberellin biosynthesis on the dormancy of potato tubers grown from true potato seed

Gibberellic acid (GA₃) and inhibitors of gibberellin biosynthesis (daminozide and chlormequat chloride) were applied to the foliage of potato plants grown from true seed (TPS) either once at two stages of plant development, 40 and 60 days after transplantation (DAT), or repeatedly at 10 day intervals starting from the same growth stages. When GA₃ was applied towards the end of the vegetative cycle (either singly 60 DAT or repeatedly from the same date), it induced rapid breakage of tuber dormancy, a reduction in specific weight, a higher rate of respiration and increased weight loss during storage. Single applications of GA₃ early in the vegetative cycle (40 DAT) had no effect on the weight loss and specific weight of tubers during storage, whereas repeated foliar applications of GA₃ starting from the same stage resulted in the formation of tubers with a low specific weight and a high rate of weight loss during storage. However, the tubers from these treatments did not break dormancy uniformly, and, although in the early stages of storage they exhibited a high rate of respiration, this declined to the level of the control (no growth regulator applied). Although daminozide and chlormequat chloride did not affect the duration of tuber dormancy and had little or no effect on any of the other metabolic indicators studied, gibberellin is nevertheless implicated in dormancy breakage, and its application late in the growth cycle may be of practical value in cases where tubers are required for planting soon after harvest. Overall, tubers from TPS respond to plant growth regulator treatment in a similar way to those from plants grown from seed tubers. Copyright © 2007 Society of Chemical Industry     

NONUNIFORM BROWNING OR "MOTTLING" IN FRENCH FRY PRODUCTS ASSOCIATED WITH A HETEROGENEOUS DISTRIBUTION OF REDUCING SUGARS

An attempt was made to relate compositional factors to the unpredictable defect of "mottling", or nonuniform browning, which develops during the finish-frying step for French fry products prepared from stored potato tubers. Potato (Russet Burbank) strip samples originating from fresh tissue and tissue processed up to the point immediately prior to finish frying, were prepared from stored tubers. Fresh and processed tissue areas that were prone to mottling had significantly (P < 0.01 to 0.05) greater levels of total sugar, glucose and fructose than did areas that were lighter in color and provided the background coloration. Glucose oxidase/peroxidase staining of surfaces of commercial French fries also showed the association of a heterogeneous distribution of glucose and the incidence of mottling. Enrichments in total and reducing sugar levels in tissue prone to mottling were modest (40–60% greater) compared to tissue along the same potato tissue strips that provided background coloration.