施氮量对糯小麦和非糯小麦籽粒淀粉组分与理化特性的影响

为探明氮肥对小麦籽粒淀粉组分和理化特性的影响,采用田间试验,分析了4个施氮量(0、100、200、300kg·hm~(-2))对糯小麦(农大糯50222)和非糯小麦(轮选987)籽粒淀粉组分与理化特性的影响。结果表明,随施氮量的增加,小麦籽粒淀粉含量降低,轮选987籽粒中B型淀粉粒的数目占比增加,而农大糯50222籽粒的B型淀粉粒数目占比呈减少趋势;增施氮肥能显著提高小麦籽粒淀粉的峰值黏度和谷值黏度。相同施氮量处理下,轮选987淀粉的被测糊化特征参数(除谷值黏度外)均大于农大糯50222。施氮量不同,2个品种籽粒淀粉X-衍射图谱中各峰的位置和相对强度明显不同。随施氮量的增加,轮选987淀粉的相对结晶度增大,而农大糯50222淀粉的相对结晶度减小。相关分析表明,小麦籽粒的直链淀粉含量和直支比与最终黏度、稀澥值、反弹值、糊化温度和峰值时间呈显著正相关,与谷值黏度和相对结晶度呈显著负相关;支链淀粉含量反之。小麦籽粒的B型淀粉粒数目占比与峰值黏度、稀澥值呈显著负相关。综上所述,施氮量可影响小麦籽粒的淀粉含量和粒度分布,进而改变其糊化特性和晶体特征。     

鲜食糯玉米品种热力学特性评价

热力学特性是评价鲜食糯玉米子粒均匀性、热稳定性和回生程度的重要指标。为了解我国鲜食糯玉米品种热力学特性,利用差示扫描量热法(DSC)测定104个鲜食糯玉米品种的热力学特性,并采用主成分分析方法对其结果进行评价。结果表明,鲜食糯玉米104个品种间淀粉热力学特征参数有显著差异,且不同参数中以回生值变异最大,回生样品的终值温度变异最小。相关分析表明,糯玉米淀粉胶凝特征参数起始温度、峰值温度、终值温度两两极显著正相关,糊化范围与峰值指数呈极显著负相关,回生热焓值和回生值呈极显著正相关。将热力学特征参数可简化为4个主成分,累计方差贡献率为86.11%。104个糯玉米品种可分为8大类,其中I和II类分别有53和43个品种,共占供试材料的92.3%,是最主要的两种类型。糯玉米淀粉热力学特征值间有良好的相关性,影响鲜食糯玉米子粒品质最重要的热力学特征值为回生值、热焓值和胶凝温度。     

不同类型小麦品种大、小淀粉粒的分离和特性

为给小麦品质育种提供依据,以3个不同类型的小麦品种(济南17号、扬麦12号和扬麦9号)为材料,分离了大、小淀粉粒,并对它们的特性(形状、大小、膨胀势、晶体特性、糊化特性等)进行了测定和分析.结果表明,大、小淀粉粒形状为椭球形或球形,品种间无差别,但其大小和含量在品种间存在很大差异;大淀粉粒的膨胀势大于小淀粉粒.大、小淀粉粒都为A型淀粉晶体,大淀粉粒的相对结晶度差别不大,但小淀粉粒的相对结晶度差别较大,表现为济南17号＜扬麦12号＜扬麦9号.品种内大淀粉粒的起始温度To、峰值温度Tp值和吸收热焓△H高于小淀粉粒,终止温度Tc值却比小淀粉粒低.     

脂肪酸对小麦淀粉糊化特性及热特性的影响

为了解脂肪酸对小麦淀粉糊化特性和热特性的影响,在小麦淀粉中分别添加月桂酸、肉豆蔻酸、棕榈酸、硬脂酸,采用快速黏度分析仪(RVA)、X-射线衍射仪(XRD)、差示扫描量热仪(DSC)对淀粉-脂质复合物糊化特性、晶体结构和热特性进行分析。结果表明,小麦淀粉与四种饱和脂肪酸所形成的复合物的晶体结构均为V型晶型。加入脂肪酸后小麦淀粉的峰值黏度、热浆黏度和崩解值降低,而最终黏度和回生值升高,起始糊化温度(To)、峰值糊化温度(Tp)、终点糊化温度(Tc)略降,而糊化焓值(ΔH)则显著下降。综合来看,添加脂肪酸对小麦淀粉的糊化特性和热特性有显著影响,其中月桂酸对小麦淀粉糊化特性及热特性的影响最显著。     

不同采收期对沪五彩花糯1号品质的影响

以沪五彩花糯1号为试材,设6个采收期,研究采收期对子粒品质和糊化特性的影响。结果表明,采收期为授粉后20 d时,沪五彩花糯1号感官和蒸煮品质综合评分达最高,为85.6分。蛋白质和可溶性糖含量随采收期推迟而降低,而淀粉则相反。不同采收期下的峰值粘度、谷值黏度、终值黏度、崩解值和回复值变异系数要大于峰值时间和糊化温度的变异系数,说明除峰值时间和糊化温度之外,峰值黏度、谷值黏度、终值黏度、崩解值和回复值受采收期影响较大。与淀粉和可溶性糖相比,子粒中的蛋白质对糊化特性的影响较大。     

基肥配施和拔节期追氮对鲜食糯玉米子粒热力学特性的影响

以苏玉糯5号和渝糯7号为材料,研究基肥配施和拔节期追氮对鲜食糯玉米子粒热力学特性的影响.研究表明,热焓值和胶凝温度受基肥配施影响较小,回生热焓值和回生值受拔节期追氮影响较小.热力学特征参数中,以回生热焓值和回生值变异系数较高.基肥配施处理中,氮磷钾肥均衡配施时各参数较高.随着拔节期追氮量增加,胶凝温度(起始温度、峰值温度和终值温度)先升后降;热焓值、回生值在不追氮或追氮150 kg/hm²时无显著差异,在过量追氮(300 kg/hm²)时前者较低,后者较高.相关分析表明,胶凝温度3个指标两两极显著正相关,且回生值和回生热焓值极显著正相关.6个热力学特征参数可转换为3个独立的主成分,累计方差贡献率为97.2%.氮磷钾均衡基施并拔节期适量追氮时子粒热稳定性较好,回生值适中.     

糯玉米子粒淀粉形态和结构对硬度的影响

以京科糯2000等3个糯玉米品种为试验材料,系统分析糯玉米子粒淀粉形态和结构对硬度的影响及各指标的相关性。结果表明,不同糯玉米品种子粒蒸煮后硬度最低的是京科糯768(2 342.00 g),其次是京科糯2000(2 504.50 g),分别比苏玉糯2号低35.50%和31.02%;蒸煮后子粒回生值以京科糯2000(966.25 g)最低,其次是京科糯768(1 142.25 g),分别比苏玉糯2号低28.56%和15.55%。不同品种糯玉米淀粉结晶度表现,苏玉糯2号(43.64%)>京科糯2000(40.96%)>京科糯768(40.59%)。淀粉颗粒平均粒径以京科糯2000最大,其次是京科糯768,苏玉糯2号淀粉颗粒平均粒径最小。相关分析表明,蒸煮后子粒硬度及蒸煮后子粒回生值与淀粉结晶度呈显著正相关,与淀粉平均粒径呈显著负相关。综合分析表明,淀粉结晶度小、淀粉颗粒大是京科糯768和京科糯2000子粒硬度小的主要原因。     

不同糯小麦品种(系)品质及其烘烤制品研究

为推动糯小麦的品质改良及开发利用,以国内不同育种单位育成的多个糯小麦为试验材料,以普通强筋、中筋及弱筋小麦作为对照,分析其淀粉组分、糊化特性、面团流变学特性,并对其制作的酥条进行比较.结果表明,糯小麦的淀粉含量及直链淀粉含量显著低于普通小麦;在淀粉糊化特性上,糯小麦的低谷黏度、最终黏度、回生值显著低于普通小麦,峰值温度...     

糯小麦与酿酒谷物黏度特性的比较

为明确糯小麦与其他酿酒谷物糊化特性的差异,为糯小麦在白酒酿造中的应用提供参考依据,比较分析了CD糯麦-2、普通小麦、糯米、高粱和玉米籽粒的淀粉RVA黏度特性。结果表明,不同作物的糊化特性有很大的差异,高梁的峰值黏度最高,糯小麦次之,玉米最低,普通小麦比糯米高,但二者差异较小;到达峰值黏度的时间为5.2~11.2 min,其中糯米糊化最快,糯小麦与糯米接近,比普通小麦快近2 min,普通小麦与高粱相近,玉米最慢;到达峰值黏度的温度为67.2~92.2℃,其中糯小麦和糯米低,分别为70.3℃和67.2℃,普通小麦和高粱分别为84.6℃和83.1℃,玉米则高达92.2℃,糯小麦比普通小麦低约14.3℃。糯小麦配粉能改变谷物的黏度特性,对糊化温度和糊化时间的影响小于对峰值黏度的影响,从不同作物考虑,糯小麦配粉对糯米的黏度特性影响相对较小。结果显示,糯小麦像糯米一样直链淀粉含量极低,其淀粉易糊化,糊化温度低,耗能少;向其他谷物中添加糯小麦可改变其淀粉黏度特性;糯小麦具有代替其他谷物酿造新型风味白酒的潜在优势。     

小麦籽粒淀粉合成动态及糊化特性的基因型差异

为了明确不同基因型小麦品种籽粒灌浆过程中的淀粉合成动态,为小麦的高产优质栽培提供参考信息,对6个不同基因型小麦籽粒形成过程中淀粉组分的变化及淀粉糊化特性进行了分析。结果表明,非糯性小麦的直链淀粉含量随着花后天数的增加呈上升的趋势,糯性小麦则呈先上升后下降的趋势,所有品种的支链淀粉含量均呈上升的趋势;不同基因型小麦直链、支链淀粉积累速率均呈单峰曲线图,不同品种直链淀粉最大积累速率出现的时间不同,而支链淀粉最大积累速率出现的时间均在花后21d;不同小麦品种的峰值粘度、低谷粘度、最终粘度均随着花后天数的增加而上升;不同品种淀粉糊化特性不同:糯性小麦之间在糊化时间、反弹值上无差异,而在峰值粘度、低谷粘度、最终粘度、稀懈值上的差异达显著水平;对于非糯性小麦,豫麦50和其他品种的多数糊化参数差异达显著水平;糯小麦和非糯小麦在糊化参数上的差异达1%显著水平。     

The mechanical properties and abrasion behavior of warp knitted fabrics for footwear

The abrasion behavior of three kinds of warp knitted fabrics, which are normally used for upper sole of footwear, was evaluated. We measured the changes of mechanical and structural properties of each sample as abrasion cycle increased. Each sample showed similar trends in compression and surface properties but there were significant differences in abrasion rate among the samples. The mechanical properties showed remarkable differences with directions. The frictional coefficient (MIU) of fabric surface increased at the beginning of abrasion and decreased as abrasion cycles increased. The weight and thickness of the fabric linearly decreased with abrasion cycles. The surface roughness (SMD) and the compressional resilience (RC) decreased as abrasion cycles increased while compressional energy (WC) increased.     

Comparative study on the effects of buckwheat by roasting: Antioxidant properties,nutrients, pasting,and thermal properties

The increasing need to prolong the shelf life of buckwheat has prompted the use of roasting techniques in buckwheat processing. For effective roasting, the responses of common buckwheat (CB) and tartary buckwheat (TB) to the process should be explored. Herein, the antioxidant properties, nutrients, pasting, and thermal properties of raw and roasted buckwheat flours (roasted at 200 °C for 50 s) from two CB and three TB varieties were investigated. Results showed that roasting considerably reduced the total flavonoid content (TFC) and total phenolic content (TPC) of TB. The TPC of CB was significantly improved by roasting, whereas the TFC significantly decreased. The total antioxidant capacities were consistent with the TPCs. Additionally, the colour deepened as the amount of antioxidant compounds increased. Unexpectedly, roasting enhanced the protein and fat contents of CB and decreased those of TB. Roasting improved the nutritional quality and antioxidant capacity of CB, and opposite results were obtained in TB. In conclusion, CB was more suitable to the development of roasted specialty products with nutritional applications than TB. We suggest that differences among varieties should be considered first in the buckwheat roasting process.     

Physicochemical and functional properties of soluble dietary fiber from different colored quinoa varieties (Chenopodium quinoa Willd)

As it is well documented that the phytochemical composition and bioactive profile of quinoa are influenced by different phenotypes, we analyzed the physicochemical and functional characteristics of different quinoa soluble dietary fiber (SDF). SDF was prepared through ultrasound-assisted enzymatic extraction from three colored quinoa brans. After purification, the yield of SDF from white (W-SDF), red (R-SDF) and black quinoa bran (B-SDF) was 2.2%, 5.7% and 5.9%, respectively. Compared with R-SDF and B-SDF, W-SDF had a higher molecular weight (1.72 × 10⁶ Da) and lower zeta-potential (- 32.16 mV), although their monosaccharide composition and Fourier transform infrared spectroscopy (FT-IR) results showed no obvious differences. The transmission electron microscope (TEM) image suggested that R-SDF exhibited a more complex and loose structure than W-SDF and B-SDF. Moreover, R-SDF exhibited higher thermal stability, gel forming capacity, bile acid binding capacity, water-holding capacity and glucose adsorption capacity than those of B-SDF and W-SDF. Taken together, SDF extracted from quinoa especially from red quinoa might be a promising candidate for the development of novel functional food ingredients.     

Preparation of starch-based polyurethane films and their mechanical properties

In this study, polyurethane films were prepared using starch as the main polyol component, and the mechanical properties of these films were investigated. The starch content of the polyols was 30–50 wt%. To confirm the formation of a urethane linkage between the −OH of starch and −NCO of toluene 2,4-diisocyanate, Fourier transform infrared (FT-IR) spectroscopic analysis was performed. Differential scanning calorimetry (DSC) thermograms of the polyurethanes resulted in two endothermic peaks, which shifted to higher temperatures with increasing starch content and −NCO/−OH molar ratio. Due to the melting behavior of polyurethane, films could be prepared by hot pressing at an appropriate temperature. Polyurethane films were prepared with various polyol starch content and −NCO/−OH molar ratios. Tensile testing indicated that the breaking stress and elastic modulus increased significantly with starch content and −NCO/−OH molar ratio. In addition, bending tests indicated an increase in breaking stress and bending modulus with starch content and −NCO/−OH molar ratio and decreased breaking strain. The strain rate in both tensile and bending tests had a significant effect on the mechanical properties.     

Pasting,thermal and rheological properties of octenylsuccinylate modified starches from diverse small granule starches differing in amylose content

Waxy maize (a standard starch of normal granule size) and five small granule starches from different botanical sources (rice, wheat B type, oat, quinoa and amaranth) were subjected to 2-octenyl-1-succinic anhydride (OSA) modification. Changes of pasting, gel texture, thermal and rheological properties were investigated. Different small granule starches showed quite different property changes after OSA modification. Pasting viscosity was generally increased in OSA starches, among which OSA oat starch had notably high peak and breakdown viscosity but low setback viscosity. Gel hardness of rice, wheat B type, oat and quinoa starches was reduced by OSA treatment, whereas that of waxy maize and amaranth starches was increased. Amylose content was considered to be the major factor influencing pasting, gel and thermal property of OSA starches. Esterification increased pseudoplastic flow behavior of all starches, while OSA oat starch uniquely had reduced flow consistency coefficient. The dynamic rheological properties were also changed differentially among OSA starches. Viscoelastic properties of rice, wheat B type, oat and quinoa starches were increased after OSA treatment, whereas those of waxy maize and amaranth starches were decreased. This study showed that diverse functionalities from OSA small granule starches may fulfil different demands in product development.     

Relationship between the Starch Properties of White-Core Tissue and Polishing Characteristics in Brewers’ Rice Kernels

References

The kernels of Hattan-nishiki No. 1 and Kairyo-omachi have larger air spaces in the white-core tissue and are broken easily during the process of polishing when compared with those of Senbon-nishiki and Yamada-nishiki. The polishing characteristics of brewers’ rice kernels are closely related with the structure of the white-core tissue of kernels. In this study, the varietal differences in the starch properties of white-core tissue of brewers’ rice kernels on polishing characteristics were studied. The starch properties were studied by rapid visco analysis (RVA) and differential scanning calorimetry (DSC); the amylose content of the rice flour of each variety was also analysed. No significant differences were observed in the amylose content among the four varieties. The two RVA parameters, peak viscosity and breakdown, were higher in Hattan-nishiki No. 1 and no significant differences were observed in them among Senbon-nishiki, Yamada-nishiki and Kairyo-omachi. The DSC parameters, gelatinization onset and peak and conclusion temperatures, were higher in Hattan-nishiki No. 1, lower in Senbon-nishiki and Yamada-nishiki, and intermediate between them in Kairyo-omachi. These results suggest that the polishing characteristics of brewers’ rice kernels are related with not only the endosperm structure but also the starch property of white-core tissue, except for Kairyo-omachi.     

Mechanical properties of breathable waterproof fabrics with seaming and sealing processes

Waterproof fabrics are seamed and sealed by waterproof sealing tape to prevent water from penetrating through the stitch holes. As this process may change the mechanical properties of breathable waterproof fabric related to its deformation with human body, the changes in mechanical properties were investigated. In both of parallel and perpendicular directions, tensile characteristics were remarkably changed with seaming and sealing processes. The increase of LT and WT means that the clothing sealed by waterproofing tape may produce somewhat discomfort feeling. On the other hand, the bridge of the sewing thread seemed to be reinforced by waterproofing tape. Shear characteristics such as G, 2HG, and 2HG5 gradually increased with seaming and sealing processes in parallel direction. However, they decreased with sealing process in perpendicular direction because the seam line work as an axis located at the center of the testing range.     

Synthesis of rosinimide modified with polyphenylpyridinylsiloxane and its characteristics

Rosin maleic anhydride adduct (RMA)-bisester was prepared by the esterification of chlorinated RMA with hydroquinone. Phenylpyridinylcyclotrisiloxane (D ₃ ^Ph,Py ) was synthesized from phenylpyridinyldichlorosilane in the presence of zinc oxide catalyst, and amino group terminated polyphenylpyridinylsiloxane prepolymer was prepared by equilibrium polymerization of D ₃ ^Ph,Py with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane. Rosinimide (PSMR) was prepared from the imidization of RMA-bisester with polyphenylpyridinylsiloxane prepolymer at 120°C for 7 h using γ-butyrolactone/pyridine. It showed that PSMR had better thermal stalbility than rosinimide modified with polydimethylsiloxane.     

重金属铜对玉米的影响

采用溶液培养的方法,研究了铜对玉米生理特性的影响。结果表明:随着铜浓度的增加,其中叶绿素含量、光合强度、根系活力和CAT活性呈逐渐下降趋势;质膜透性、脯氨酸含量、MDA含量和SOD活性上升;POD活性表现为低浓度刺激效应和高浓度的抑制效应。