参薯干粉中总还原糖含量的测定

以葡萄糖为标准,以3,5-二硝基水杨酸(DNS)作显色剂,用分光光度法测定参薯干粉中总还原糖的含量。结果表明:在波长470nm处有最大吸收峰,测定重现性好,标准回收率高,相对误差小,效果好。     

参薯抗性淀粉的压热法制备工艺

为提高参薯淀粉转化为抗性淀粉的产率,对参薯淀粉的压热法制备抗性淀粉进行了研究。以参薯淀粉为原料,通过单因素试验分析各种因素对抗性淀粉产率的影响;经过三因素二次正交旋转组合设计结合响应面分析,得出淀粉乳浓度、pH、压热时间对抗性淀粉含量的影响大小次序:淀粉乳浓度>pH>压热时间;最佳工艺条件为淀粉乳质量浓度33.00%,pH 7.6,121℃压热处理36 min,4℃下老化处理24 h,80℃烘干18 h,得到的抗性淀粉质量分数为13.92%。     

山药颗粒结合型淀粉合成酶基因DaGBSS的克隆与分析

颗粒结合型淀粉合成酶（granule-bound starch synthase, GBSS）是一种能够决定直链淀粉生物合成的关键性酶。通过对山药转录组分析以及分子克隆获得一个具有完整ORF的DaGBSS基因,cDNA片段长度为1845 bp,编码614个氨基酸。生物信息学分析结果显示DaGBSS蛋白为一酸性稳定蛋白,含有淀粉合酶催化和糖基转移酶两个功能结构域。多序列比对结果显示：糯米山药DaGBSS蛋白与所选的物种具有较高的同源性,且含有典型的功能结构域;生物进化分析结果显示DaGBSS蛋白与圆形薯蓣亚种进化亲缘关系最近。对采收15天山药块茎进行处理,qRT-PCR以及指标分析结果显示DaGBSS基因在山药块茎的表达存在明显的时空差异性,且在距离地表位置最远的部位DaGBSS基因的表达量、GBSS和直链淀粉的含量均为最高。该研究通过对山药块茎淀粉合成的早期阶段进行生理以及关键调控因子的克隆分析,为探究山药淀粉合成的调控提供理论依据,同时对糯米山药的分子育种提供了重要的基因资源。     

紫脚板薯淀粉的提取工艺研究

以NaOH为浸泡剂,探讨了紫脚板薯料液比、浸提时间、浸提温度、浆料pH对淀粉提取率的影响,并通过正交试验确定了紫脚板薯淀粉的最佳提取工艺。结果表明:料液比1:6,浸提时间1.5 h,浸提温度35℃,浆料pH 8时,紫脚板薯淀粉的提取率最高,约为83.7%。     

紫参薯中花色苷提取工艺研究

紫参薯中含有大量的花色苷,通过单因素试验和正交实验确定紫参薯块茎中花色苷提取的最佳工艺条件.实验表明,最佳提取条件:50％乙醇为提取剂,提取温度70℃,提取时间1h,提取料液比1∶15.实验将提取环境确定为pH2.0,减少了花色苷的降解,同时降低了成本.     

Effect of acid–ethanol on the physicochemical properties of Dioscorea opposita Thunb. and Pueraria thomsonii Benth. starches

Dioscorea opposita Thunb. and Pueraria thomsonii Benth. starches were hydrolyzed with 0.36% HCl under ethanol conditions during 1, 3, 5, 8, and 12 h. Structural and physicochemical characteristics studies of C‐type D. opposita Thunb. and P. thomsonii Benth. starches were carried out using SEM, XRD, and FTIR spectroscopy. From the FTIR result, it was determined that the amorphous areas of starch granules were hydrolyzed successfully. The SEM and XRD results revealed that the interior was preferentially hydrolyzed and the degree of crystallinity increased for D. opposita and P. thomsonii starches. However, the two kinds of starches were hydrolyzed in different ways. The starch granules of D. opposita presented bread‐like in shape after acid hydrolysis. While the P. thomsonii Benth. starch granules were degraded for concaves formed on the surface, and several small particles appeared. Water‐binding capacity and AM content were observed to be lower for both starches. The thermal results revealed that the hydrolyzed starches showed the lower ΔH_gel than the native starches, which can be related to the preferential destruction of amorphous areas in the granules.     

Comparison of starches separated from different Dioscorea bulbifera Linn. cultivars

The physico‐chemical, morphological, thermal, and crystal properties of the starches separated from three different rhizomes of Dioscorea bulbifera Linn. (D.BLH, Hubei; D.BLG1, Guangxitianlin; D.BLG2, Guangxiyulin) were studied and compared. A light microscopic technique was applied in order to quantify the integrity and shape of the starch granules after isolation. Amylose contents of different cultivars were in the range of 12.18–14.34%. Moisture content, ash content, swelling power, solubility, water‐binding capacity, and protein content of starches also differed significantly. The three different D. bulbifera starches all showed a typical C‐type pattern with crystallinity 45.36, 27.10, and 53.04%, corresponding to D.BLH, D.BLG1, and D.BLG2, respectively. The starch separated from the three starches above showed gelatinization range of 10.09, 11.55, and 7.26°C, corresponding to D.BLH, D.BLG1, and D.BLG2. The enthalpy of gelatinization (ΔH_gel) ranged from 1.28 to 3.11 J/g. Correlation analysis displayed that amylose content and relative crystallinity values were important in determining thermal starches.     

Genetic diversity of organoleptic properties in water yam (Dioscorea alata L)

Improving the food quality of yams (Dioscorea spp) is an ongoing challenge to yam breeders and researchers. Forty accessions of D alata were evaluated for the suitability of their tubers for the preparation of two dominant food forms (boiled and pounded) as part of an effort to identify potential parents for use in genetic improvement. Trained panellists were presented with randomised, replicated and coded samples of boiled yam tuber pieces and asked to rate them for mealiness, colour, wetness, softness and taste. The sensory attributes considered for pounded yam (dough from boiled and pounded tubers) were consistency, colour, sheen, smoothness, stickiness, elasticity and hardness. Ratings were based on hedonic scales. Cluster analysis revealed groupings of accessions into eight and nine similarity clusters for boiled yam and pounded yam respectively. The mean scores for general preference were regressed on individual attribute scores. Mealiness, colour and taste were important in the general preference for boiled yam. Consistency, colour and stickiness determined the general preference for pounded yam. Of the accessions, 67% were identified as being suitable for preparation as a boiled vegetable, while 55% were assessed to be good for pounded yam, based on the respective quality attributes evaluated. © 2003 Society of Chemical Industry     

脚板薯淀粉理化特性研究

采用碱法工艺提取脚板薯淀粉,并对其组成、透明度、冻融稳定性、凝沉性、持水性、溶解度、膨胀度、糊化和黏度特性等理化性质进行了分析。结果表明:脚板薯直链淀粉含量为27.05%,淀粉透明度、凝沉性、持水力、热稳定性较好,但冻融稳定性差,不易糊化,脚板薯淀粉的溶解力和膨润力随着温度的升高而增大,与水之间的相互作用较强。     

Effect of Yam (Dioscorea alata Compared to Dioscorea japonica) on Gastrointestinal Function and Antioxidant Activity in Mice

ABSTRACT:  Effects of Chinese yam ( Dioscorea alata) and Japanese yam ( Dioscorea japonica ) on gastrointestinal functions including intestinal microflora and intestinal enzymes' activities, as well as antioxidant protection against lipopolysaccharide (LPS)-induced oxidative damage, in Balb/cA mice were examined. In part I, mice were fed yam-supplemented diet for 4 or 8 wk, and killed with carbon dioxide. In part II, mice were fed yam-supplemented diet for 4 wk, and followed by intraperitoneal LPS treatment (i.p. 4 mg/kg bodyweight). The intake of Chinese yam and Japanese yam significantly changed intestinal microflora, in which the colony numbers of Bifidobacterium and Lactobacillus were increased and the colony numbers of Clostridium perfringens were decreased ( P < 0.05). The intake of both Chinese and Japanese yams also significantly elevated the activity of leucine aminopeptidase and lipase ( P < 0.05), and the activities of sucrase and maltase were increased only in 20% yam-treated groups ( P < 0.05). The preintake of yam significantly alleviated subsequent LPS-induced oxidative injury by decreasing lipid oxidation level and fibronectin production and elevating superoxide dismutase activity ( P < 0.05). Both Chinese and Japanese yams contained dietary fibers, polyphenols, and flavonoids, which may contribute to the observed gastrointestinal function and antioxidant protection. These results suggest that both Chinese yam and Japanese yam were beneficial for intestinal health and oxidation prevention.     

湿法消解-原子吸收光谱法测定紫山药中矿质元素

以福建省武平县和云南省红河州紫山药块根为实验材料,采用湿法消解-原子吸收光谱法对其中12 种矿质元素含量进行分析检测。结果表明：湿法消解-原子吸收光谱法能准确测定紫山药中矿质元素的含量,回收率在92.00%～106.00%之间,相对标准偏差在10%以下,且方法简单、快捷;供试的紫山药中矿质元素含量丰富,不仅富含Mg、Fe、Zn,还含有对人体有益的Se元素。重金属中除了Ni元素,其他重金属（Cr、Pb、As、Cd、Hg）的含量均符合GB 2762-2012《食品中污染物限量》。     

怀山药抗性淀粉理化性质及体外消化性研究

分析比较怀山药淀粉和压热法制备的怀山药抗性淀粉的理化性质及消化特性。结果表明:怀山药淀粉颗粒表面光滑,呈不规则且大小不一的椭球形、三角形等形态,属于C型淀粉;抗性淀粉颗粒特征消失,呈现表面疏松的片层状结构。2种淀粉化学结构相似,抗性淀粉没有形成新的基团。与原淀粉相比,抗性淀粉分子量分布更加集中。抗性淀粉的糊化峰值温度高于原淀粉的,因此其热稳定性更高。抗性淀粉的透明度低于原淀粉的。水浴温度低于75℃时,抗性淀粉的持水性大于原淀粉的,而当水浴温度高于原淀粉糊化温度时,原淀粉的持水性明显高于抗性淀粉的;体外模拟人体消化试验表明,抗性淀粉比原淀粉更耐消化。     

Variability in starch physicochemical and functional properties of yam (Dioscorea sp) cultivated in Ivory Coast

An Erratum has been published for this article in Journal Of the Science of Food and Agriculture 85(5), 889 (2005). Native starches were extracted from 21 cultivars of four yam species representative of the yam population of Ivory Coast. They were first characterized for their proximate composition, starch physico‐chemical properties (amylose content, particle size distribution, crystallinity, thermal properties and intrinsic viscosity). Some functional properties (swelling, solubility and pasting behaviour and paste clarity) were then determined. Analysis of variance and principal component analysis showed that three homogenous groups could be distinguished, mainly based on starch physico‐chemical properties. The first group contained all yam starches of the D alata and the D cayenensis‐rotundata complex species. It was characterized by a large diameter grain (approximately 25 µm), a high amylose content (around 25% db), a high intrinsic viscosity (mean of 190 cm³ g^?1), and a high apparent viscosity and clarity of the paste. The second group contained the D esculenta varieties, characterized by a small granule size (diameter 6 µm), a low intrinsic viscosity (121 cm³ g^?1), a high gelatinization enthalpy change (19 J g^?1) and a low paste viscosity. The D dumetorum sample differed from the D esculenta group by having a pure A‐type crystalline form and an opaque paste. A multiple regression showed that the volume fraction of the dispersed phase and native granule size (or amylose content) could account for close to 80% of the variability of paste apparent viscosity. Gel clarity appeared mainly linked to granule size, small granules from D dumetorum and D esculenta giving the most opaque gels. Copyright © 2004 Society of Chemical Industry     

Effect of phosphoric acid treatment on physicochemical,functional, and structural properties of starch extracted from yam (Dioscorea rotundata)

This work was designed to elucidate selected physicochemical, functional, and structural properties of native and modified yam (Dioscorea rotundata) starch. The isolated starch was chemically modified using 5, 10, 15, 20, and 25% phosphoric acid solution at 50°C for 1 h, and yield, swelling power, gelation, water holding capacity, paste clarity, blue value, and amylose and amylopectin content of the native and modified yam starch were determined. Structural changes in the native and starch modified with 25% phosphoric acid were evaluated using Fourier transform infrared spectroscopy and optical microscopy. The result showed that the yield, swelling power, water holding capacity, paste clarity, blue value and amylose and amylopectin content of native yam starch was 33.38% (217 g), 3.84 g/g, 1.0 v/g, 10%, 0.52 and 25.96, respectively, whereas gelation study of the native and modified starch indicated that native starch was viscous and modified starch firm. However, yield, swelling power, water holding capacity, paste clarity, blue value, and amylose content of modified yam starch reduced in a dose dependent manner with phosphoric acid. The reduction in the values of the various functional properties could be associated with the effect of phosphoric acid on the starch granular structure. The result of Fourier transform infrared spectroscopy and optical microscopy revealed that the yam starch was modified by phosphoric acid with changes in functional groups spectra such as –OH stretch (3177 cm^?1), H₂O absorbed (1644 cm^?1) (amorphous region), C-H stretch (2923 cm^?1), CH₂O (1253 cm^?1), and C-O-C (1078 cm^?1) when compared to native starch. The morphology of native and modified yam starch granules ranged from oval to eliptical. However, modified starch granules were rough in surface. In conclusion, the characterized physicochemical and functional properties and structure exhibited by native and modified yam starch indicated that, yam could be a cheap and valuable source of starch for industrial application.     

脚板薯淀粉的发酵法制备及其淀粉糊流变特性研究

采用发酵法制备脚板薯淀粉,分析了其淀粉颗粒粒度、淀粉糊透明度及凝沉性等理化性质,并对淀粉质量浓度、糊化pH、温度、不同介质及其浓度对淀粉糊流变特性的影响进行了分析。结果表明:脚板薯淀粉得率为15.2%,纯度为97.6%;淀粉平均粒度为18291.5nm,淀粉糊透光率为27.92%,其凝沉时间短;淀粉糊黏度随着淀粉浓度的增加而增加,随着糊化温度的增加而减小;在酸性条件下,淀粉糊黏度随着糊化pH增加而减小,pH到达8时,黏度达最大值,后随碱性的增强淀粉糊黏度下降。加入食盐、氯化钙和蔗糖均可提高淀粉糊的黏度,且在相同的剪切速率下,淀粉糊黏度随着蔗糖添加量的增大而增大。     

Physico‐chemical characteristics of non‐irradiated and γ‐irradiated yams cultivars (Dioscorea rotundata,Dioscorea alata) and sweet potato (Ipomoea batatas (L) Lam)

Physico‐chemical (pasting) properties of non‐irradiated (fresh) and γ‐irradiated yam cultivars and sweet potato were determined using Rapid Visco Analyser (RVA). Generally, pasting characteristics of the commodities decreased significantly with increased γ‐irradiation dose. Non‐irradiated sweet potato showed significantly higher peak (45.79), trough (35.25), breakdown (10.54), final (75.21) and setback (39.96) viscosities (in RVU) than γ‐irradiated samples. Also, peak time (6.97 min) and pasting temperature (50.18 RVU) significantly reduced with increased γ‐irradiation dose of tubers. The pasting properties of non‐irradiated and γ‐irradiated sweet potato showed similar but clearer trend compared with yam flours. Also, non‐irradiated and γ‐irradiated Dioscorea rotundata and Dioscorea alata showed significantly higher values of each of the pasting characteristics than values noted in sweet potato. Aside from the TDr 03/00196, peak time did not vary significantly with γ‐irradiation dose.     

橡子淀粉基本理化特性和多酚类物质组成分析

探讨橡子淀粉基本理化特性和其多酚组成。进行橡子淀粉碘液鉴定,润胀能力、水解能力、直链淀粉和支链淀粉含量测定,特征官能团傅里叶变换红外光谱分析,黏度变化流变仪分析,形貌显微镜观察,酚类物质组成HPLC和LC-MS分析。结果表明:橡子淀粉碘液生蓝紫色;润胀能力为(178. 00±13. 35) g/g;葡萄糖转化率为(0. 23±0. 025) g/g;直链淀粉和支链淀粉质量分数分别为19%和81%;橡子淀粉红外光谱峰型特征与马铃薯淀粉和糯米淀粉基本相似,黏度随温度变化类似马铃薯淀粉,形貌显微镜观察呈球形,多酚的质量百分数为(1. 60±0. 11)%,主要组分为鞣花酸(1. 54 g/100 g)和少量槲皮素(0. 064 g/100 g)。橡子淀粉具有一般淀粉的基本特性,其中酚类物质主要为鞣花酸。     

The physicochemical and binder properties of starch from Persea americana Miller (Lauraceae)

Avocado starch was extracted from the kernels of the fruit Persea americana Miller (Fam. Lauraceae) and evaluated for its potential as an alternative to maize starch as a pharmaceutical excipient. Its physicochemical and thermal properties were evaluated and compared with those of maize starch. Granules prepared with avocado and maize starch pastes as binder were evaluated for their flow, friability and compaction characteristics. The average yield of starch extracted from the fresh kernels of P. americana was 20.5 ± 0.55% w/w. The scanning electron micrograph (SEM) showed that avocado starch has two characteristic granule shapes; triangular and circular both having an approximate equal distribution. The triangular shaped granules are larger (28 to 32 µm) than the circular (6 to 9 µm). The foaming capacity of avocado starch was 19.05 ± 0.6%, its swelling, moisture uptake and paste clarity were generally lower than that of the maize starch. Avocado starch gel exhibited an extent of syneresis after freeze–thaw that increased cumulatively with increase in number of freeze–thaw cycles. The glass transition (T_g) and gelatinisation temperatures for avocado starch were higher than that of maize starch. The melting temperatures (T_m), ash value, as well as the various densities of avocado starch showed similarities with those of maize starch. The granules prepared with avocado starch pastes as binder showed superior compactibility and mechanical strength to those of maize starch but with similar flow characteristics. Avocado starch generally showed distinct physicochemical and binder properties with some similarities to the standard maize starch.