Cross-Linking of Sago Starch with Furan and Bismaleimide via the Diels-Alder Reaction

This research paper describes the synthesis of thermo-reversible cross-linking of sago starch by grafting a furan pendant group(methyl 2-furoate)onto the starch backbone,followed by a Diels-Alder(DA)reaction of the furan functional group with 1,1′-(methylenedi-4,1-phenylene)bismaleimide(BM).The proof of principles was provided by FTIR and 1H-NMR analyses.The relevant FTIR peaks are the carbonyl peak(υC=O sym)at 1721 cm^(−1);the two peaks appeared after DA cross-linking,i.e.,at 1510 cm^(−1)(corresponding toυCH=CH BM aromatic rings,stretching vibrations),and at 1173 cm^(−1)(assigned to cycloadduct(C-O-C,δDA ring))while the^(1)H-NMR result shows evidence for the presence of a furan ring in the starch matrices(in the range ofδ6.3-7.5 ppm).The crosslinked starch product is indeed thermally reversible,as is evident from the appearance of exothermal(DA,temperature range of 50℃-70℃)and endothermal(retro DA,temperature range of 125℃-150℃)transitions in the DSC thermograms.This paper not only proves the thermal reversibility but also demonstrates that the final product properties(chemical,morphology,and thermal stability)can be tuned by varying the annealing temperature,BM intake,and reaction time.

Insights into the swelling process and drug release mechanisms from cross-linked pectin/high amylose starch matrices

Cross-linked pectin/high amylose mixtures were evaluated as a new excipient for matrix tablets formulations,since the mixing of polymers and cross-linking reaction represent rational tools to reach materials with modulated and specific properties that meet specific therapeutic needs.Objective:In this work the influence of polymer ratio and cross-linking process on the swelling and the mechanism driving the drug release from swellable matrix tablets prepared with this excipient was investigated.Methods:Cross-linked samples were characterized by their micromeritic properties(size and shape,density,angle of repose and flow rate)and liquid uptake ability.Matrix tablets were evaluated according their physical properties and the drug release rates and mechanisms were also investigated.Results:Cross-linked samples demonstrated size homogeneity and irregular shape,with liquid uptake ability insensible to pH.Cross-linking process of samples allowed the control of drug release rates and the drug release mechanism was influenced by both polymer ratio and cross-linking process.The drug release of samples with minor proportion of pectin was driven by an anomalous transport and the increase of the pectin proportion contributed to the erosion of the matrix.Conclusion:The cross-linked mixtures of high amylose and pectin showed a suitable excipient for slowing the drug release rates.

Influence of starch sources and dietary protein levels on intestinal functionality and intestinal mucosal amino acids catabolism in broiler chickens

Background: There is growing interest in carbohydrate and protein nutrition to enhance the efficiency of animal production.Reduced-crude protein diets depress environmental pollution and feeding cost,but the challenge to their adoption is maintaining digestive function and growth performance of birds.The present study was conducted to evaluate the influence of different dietary starch sources and protein levels on intestinal functionality and mucosal amino acid catabolism.Methods: Six dietary treatments,based on maize and soybean meal,were offered to 360 AA+male chicks from 6 to 35 d post-hatch as a 3 × 2 factorial array.Either waxy rice or amylose was added to a conventional maize-soy diet to provide three sources of starch with different digestion rates and relatively high and low dietary protein levels.Growth performance,parameters of intestinal functionality and concentrations of free amino acid in the portal circulation were determined.Results: In the grower phase,starch source influenced(P < 0.02) weight gain as diets containing amylose supported significantly higher weight gains than waxy rice.Significant increase of ileal ATP concentrations and Na^+/K^+-ATPase activity were found in amylose treatment.Also,amylose decreased BrdU positive cell numbers and down-regulated m RNA expression for CASP-3.GOT activity in the ileum was higher(P < 0.01) in birds offered low protein diets and there was a trend(P = 0.057) for waxy rice as a starch source to increase ileal GOT activities.There was a significant influence on the concentration of seventeen amino acids in the portal circulation with tryptophan the one exception.Waxy rice as a starch source generated 13.6% and 22.4% numerically higher concentrations of non-essential amino acids than maize and amylose,respectively.Conclusions: Amino acid catabolism in the gut mucosa is subject to nutritional regulation.Given that amino acids can be spared from catabolism in the gut mucosa by supplementation of amylose,it follows their post-enteral availability would be improved and intestinal energy would be derived more efficiently from glucose.

Cross-linkedα-amylase aggregates on Fe3O4 magnetic nanoparticles modified with polydopamine/polyethyleneimine for efficient hydrolysis of starch

In this workα-amylase was immobilized on magnetic Fe3O4 nanoparticles with polyethylenimine(PEI)/polydopamine(PDA)coating or 3-aminopropyl triethoxysilane(APTES)for the first time via adsorption–precipitation–cross-linking.Compared with the freeα-amylase,the resultant magnetic cross-linkedα-amylase aggregates(PEI/PDA-M-CLEAs and N-M-CLEAs)exhibited excellent thermal and storage stability as well as pH stability.After storage at 25°C for 60 days,freeα-amylase only retained 60%of its initial activity,while PEI/PDA-M-CLEAs and N-M-CLEAs retained 80%and 78%of their initial activities,respectively.Furthermore,N-M-CLEAs and PEI/PDA-M-CLEAs showed good reusability.After 6 repeated uses,PEI/PDA-M-CLEAs and N-M-CLEAs still maintained 65%and 62%of their initial activities,respectively.Especially,PEI/PDA-M-CLEAs and N-M-CLEAs exhibited higher starch hydrolysis efficiency than freeα-amylase.The maximum dextrose equivalent(DE)values of starch hydrolysis by PEI/PDA-M-CLEAs and N-M-CLEAs reached 29.24%and 28.79%within 90 min,respectively.However,the maximum DE values of starch hydrolysis by the freeα-amylase was only 27.89%even in 150 min.The magnetic cross-linkedα-amylase aggregates could be introduced as effective biocatalyst for industrial applications in production of maltose syrups.

Different dietary starch sources alter the carcass traits, meat quality, and the profile of muscle amino acid and fatty acid in finishing pigs

Background: With increasing health awareness among consumers, the demand for healthier, tastier, higher quality and nutritional value pork is increasing. It has been shown that different dietary starch sources can alter the carcass traits and meat quality. However, research on the effects of different starch sources with clear different amylose/amylopectin ratio on the amino acid and fatty acid composition in Longissimus thoracis(L. thoracis) muscle of pigs is limited. This study aimed to investigate the effects of different dietary starch sources on carcass traits, meat quality, muscle amino acid and fatty acid composition, and the mRNA expression levels of genes involved in lipid metabolism and muscle fiber characteristics in finishing pigs. A total of 72 Duroc × Landrace × Large White barrows were randomly allocated to 3 different dietary treatment groups with 8 replicate pens/group and 3 pigs per pen.Tapioca starch(TS), corn starch(CS), and pea starch(PS), with amylose/amylopectin ratio of 0.11, 0.25, and 0.44,respectively, were used as their dietary starch sources for 40 days.Results: Results showed that the PS diet significantly increased(P < 0.05) the final body weight, average daily gain,loin-eye area, and fat-free lean index compared with the TS diet, but significantly decreased(P < 0.05) the feed to gain ratio and backfat thickness. Compared with the TS diet, PS diet also increased(P < 0.05) the pH45 min, marbling scores, the content of intramuscular fat and inosine monophosphate in the L. thoracis, and decreased(P < 0.05) the drip loss and shear force. In addition, compared with the TS diet, PS diet increased(P < 0.05) the proportions of flavor amino acids, DHA, EPA, and n-3 polyunsaturated fatty acid(PUFA) in the L. thoracis compared with TS diet,but decreased(P < 0.05) the ratio of n-6/n-3 PUFA. Furthermore, compared with the TS diet, PS diet also upregulated(P < 0.05) the lipogenic genes(FAS, LPL, SCD, ACCα) and myosin heavy-chain(MyHC)-IIa mRNA expression levels compared with the TS diet, but downregulated(P < 0.05) the CPT1 B and MyHC-IIb mRNA levels.Conclusions: In conclusion, these results provided compelling evidence that the different dietary starch source altered the carcass traits, meat flavor and quality in finishing pigs, and consumption of a diet with higher amylose/amylopectin ratio results in the production of a healthy, higher quality, and nutritional value pork.

Study on Various Compositions of Polyvinyl Alcohol and Starch Blends by Cross-Linking with Glyoxal

The aim of this study is to analyze the various compositions of polyvinyl alcohol (PVA) and starch blends. The blends have been cross-linked with glyoxal to enhance its properties. The hydroxyl groups of PVA and starch react with glyoxal via formation of acetal bonds;hence crosslinking could take place. The cross-linking of glyoxal is observed in various analytical methods such as DSC and FTIR. The cross-linked blends showed better thermal and mechanical properties. Viscosity, tensile shear strength, pencil hardness and ultimate stress were evaluated to estimate the changes due to cross-linking. It was observed that the cross-linking is directly proportional to starch, since the starch hydroxyl groups are easily accessible for reacting. The cross-linked blend showed better cohesion between its chains, thereby increasing glass transition temperature. It was reflected in the subsequent increase in tensile strength properties.

中高温大曲发酵中小麦籽粒营养组分的动态变化分析

该研究利用离子色谱和高效液相色谱等方法,研究了中高温大曲不同发酵时期小麦营养成分的变化及其与微生物群落演替间关系。结果表明,曲皮和曲心分别消耗了直链淀粉含量的39.08%和49.12%,支链淀粉含量的84.43%和81.35%,A型淀粉粒的6.41%和26.92%,B型淀粉粒的66.67%和83.33%。麦谷蛋白含量从8 mg/g降为4.73 mg/g(曲皮)和3.53 mg/g(曲心)。黄酮含量从0.08 mg/g增加到0.12 mg/g(曲皮)和0.29 mg/g(曲心)。纤维素含量总体呈下降趋势,但曲心后期有平缓上升;阿拉伯糖和蔗糖含量增加,葡萄糖含量降低。曲心游离氨基酸含量增加幅度高于曲皮,其中谷氨酸含量最高。冗余分析表明18个品质指标与9个细菌属和11个真菌属的相对丰度显著相关(P<0.05),其中直链淀粉含量与叶杆菌属(Phyllobacterium),葡萄糖、果糖、支链淀粉含量与醋酸单胞菌属(Acetobacter)、双杆菌属(Undibacterium)、乳杆菌属(Lactobacillus)均显著正相关。因此,具有高支链淀粉和高葡萄糖含量的小麦品种可能更适用于制曲。该研究结果为探究大曲质量控制、小麦品质与大曲品质间关系,以及选育专用型原料(小麦)品种提供参考。

反刍动物对饲料蛋白质和淀粉消化吸收的研究进展

蛋白质是饲料中最主要的氮源,淀粉是饲料中最重要的供能物质,二者通过瘤胃发酵、降解后在小肠中被吸收,是维系能氮平衡的主要物质。该文综述了淀粉的消化特性、蛋白类饲料和淀粉类饲料分类,以及反刍动物对其消化吸收的研究进展,旨在为饲料利用效率的提高提供参考,为发展精准饲养和节粮型畜牧业提供理论依据。

Starch-Based Adhesives for Wood/Wood Composite Bonding: Review

Increasing global energy crisis and scarcity of petroleum resources has shifted focus of chemical industries to look for alternative raw material resources. The main focus of raw materials in wood adhesives, such as petroleum and natural gas [1] [2], would be gradually replaced by renewable biopolymers. Starch is a relatively inexpensive and renewable product from abundant plants, easy processing and it has been extensively used as binders, sizing materials, glues and pastes [3], but its bonding capacity is not strong enough to glue wood [4]. Extensive research has been carried out on improving the cohesive properties, especially water resistance, of starch-based adhesives. In starch-based wood adhesive many new approaches have come forward for effective use it in wood/wood composite adhesive giving comparable performance as synthetic adhesives. This review of starch-based adhesives is made with the focus on starch modification methods for improving properties of starch-based adhesives.

Transformation of Sucrose to Starch and Protein in Rice Leaves and Grains under Two Establishment Methods

Six rice varieties, PR120, PR116, Feng Ai Zan, PR115, PAU201 and Punjab Mehak 1 were raised under aerobic and transplanting conditions to assess the effects of planting conditions on sucrose metabolising enzymes in relation to the transformation of free sugars to starch and protein in flag leaves and grains. Activities of sucrose synthase, sucrose phosphate synthase and acid invertase increased till flowering stage in leaves and mid-milky stage（14 d after flowering） in grains and thereafter declined in concomitant with the contents of reducing sugar. Under aerobic conditions, the activities of acid invertase and sucrose synthase（cleavage） significantly decreased in conjunction with the decrease in non-reducing sugars and starch content in all the varieties. Disruption of starch biosynthesis under the influence of aerobic conditions in both leaves and grains and the higher build up of sugars possibly resulted in their favoured utilization in nitrogen metabolism. Feng Ai Zan, PR115 and PR120 maintained higher levels of sucrose synthase enzymes in grains and leaves and contents of metabolites（amino acid, protein and non-reducing sugar） under aerobic conditions, while PR116, Punjab Mehak 1 and PAU201 performed better under transplanting conditions, thus showing their adaptation to environmental stress. Yield gap between aerobic and transplanting rice is attributed primarily to the difference in sink activity and strength. Overall, it appear that up-regulation of sucrose synthase（synthesis） and sucrose phosphate synthase under aerobic conditions might be responsible in enhancing growth and productivity of rice varieties.

低谷蛋白半糯型粳稻品种(品系)的氨基酸组分含量及淀粉理化性质

氨基酸含量是评价稻米营养品质的重要指标之一,提高稻米中的氨基酸含量,尤其是提高赖氨酸等必需氨基酸含量是提高稻米品质的重要目标。低谷蛋白半糯型粳稻品种是一种具有低直链淀粉含量、低谷蛋白含量特性的新型粳稻品种,适合肾病患者食用。为了明确低谷蛋白半糯型粳稻品种(品系)的氨基酸组分含量与淀粉理化特性,以低谷蛋白半糯型粳稻品种(品系)为材料,半糯型粳稻、普通粳稻品种为对照,在相同生态环境和栽培条件下种植3种不同类型的粳稻品种(品系)共16个,测定并分析稻米总氨基酸含量及各氨基酸组分含量,同时分析直链淀粉含量、糊化温度、胶稠度等淀粉理化特征,并进一步分析氨基酸组分含量与淀粉理化指标的相关性。结果表明,3种类型粳稻品种(品系)间的总氨基酸、赖氨酸、苏氨酸及谷氨酸含量存在显著差异,低谷蛋白半糯型粳稻的总氨基酸、赖氨酸的平均含量显著低于半糯型粳稻、普通粳稻,半糯型粳稻谷氨酸的平均含量显著高于低谷蛋白半糯型粳稻、普通粳稻。低谷蛋白半糯型粳稻的崩解值显著低于半糯型粳稻、普通粳稻,半糯型粳稻的胶稠度与峰值黏度显著高于普通粳稻、低谷蛋白半糯型粳稻;赖氨酸、苏氨酸含量与峰值黏度、食味值呈显著或极显著负相关,与硬度呈显著或极显著正相关。3种不同类型粳稻品种(品系)在赖氨酸含量、直链淀粉含量和崩解值上存在显著差异,其中低谷蛋白半糯型粳稻品种(品系)的赖氨酸含量最低,半糯型粳稻品种具有较低的直链淀粉含量、消减值和回复值,同时具有较高的谷氨酸含量、胶稠度和崩解值。17种氨基酸中,赖氨酸含量对米饭食味品质的影响最大,与米饭的外观、黏度和食味值呈极显著负相关。

GABA富化处理的大米产品的成分分析与营养评价

近年来随着人们生活水平的迅速改善,人们更加关注膳食营养健康。在本研究中,为了分析经过GABA富化装置处理前后稻谷的营养成分和功能组分变化,测定了GABA、游离氨基酸、蛋白质、还原糖、抗性淀粉和总淀粉等指标的含量。经过GABA富化处理后,精米中的还原糖含量由1.53 mg/g减少到0.341 mg/g;淀粉含量由746 mg/g减少到728 mg/g;而抗性淀粉含量由1.96%增加到2.30%;GABA含量由84.1μg/g增加到111μg/g;游离氨基酸含量由1114μg/g增加到1123μg/g;必需氨基酸含量由419μg/g增加到426μg/g。总蛋白含量几乎不变,且蛋白质组成符合理想蛋白质的要求。

螯合淀粉衍生物对铜离子吸附性能的研究

以玉米淀粉为原料 ,经交联、间接醚化、胺化反应合成了交联氨基淀粉 (CAS) ,CAS进一步与CS2 亲核加成反应 ,合成了带有二硫代氨基甲酸 (DTC)基团的DTC改性淀粉(DTCS) .研究了CAS和DTCS吸附铜离子的动力学行为 ,结果表明 ,二者对铜的吸附均符合Freundlich等温式 .2 98K时 ,CAS和DTCS的吸附速率常数分别为k =1 75 8h- 1 和k =1 0 32h- 1 .根据对吸附行为的研究得到了表观动力学方程和热力学参数 。

乙二胺改性淀粉GMA共聚物对Pb(Ⅱ)的吸附性能

以木薯淀粉为原料,通过接枝共聚、环氧开环反应,得到富含—NH2官能团的新型氨基改性淀粉（AMS）,用FT-IR、SEM和XRD对其结构进行表征。在静态条件下,研究了AMS对水溶液中Pb（Ⅱ）的吸附性能和吸附热力学,考察了溶液pH值、吸附时间、Pb（Ⅱ）初始浓度及温度对AMS吸附性能的影响。结果表明：pH值对AMS的吸附性能有显著影响;该吸附是一个快速吸附过程,符合准二级动力学方程,以化学吸附为主;吸附等温线用Langmuir方程拟合效果优于Freundlich方程;分离因子在0~1之间;在初始浓度100mg.L-1,pH值为6.0、25℃下的最大吸附容量为0.481 mmol.g-1;吸附为自发、吸热的熵增加过程,升温有利于吸附;AMS可重复使用5次以上。

氨基酸对大米淀粉糊化和流变性质的影响

以赖氨酸(lysine,Lys)、天冬氨酸(aspartic acid,Asp)和丙氨酸(alanine,Ala)分别代表带正电、负电、不带电3类氨基酸,采用快速黏度分析仪和流变仪研究氨基酸对大米淀粉糊化和流变性质的影响。结果表明,Lys和Asp均显著提高了大米淀粉的峰值黏度和崩解值(P<0.05),但是降低了淀粉的最终黏度和回生值,而Ala对淀粉的糊化性质影响微小,在一定浓度范围内无显著差异(P>0.05)。因此,带电的2种氨基酸(Lys和Asp)比不带电氨基酸(Ala)对淀粉糊化性质影响更强。此外,3种氨基酸对大米淀粉糊流变性质影响不同:动态流变学实验中,添加Lys和Ala使淀粉凝胶更具弹性,而Asp使淀粉凝胶变弱;静态流变学实验中,运用幂定律τ=kγm,对剪切应力τ和剪切速率γ进行了拟合,结果表明,原淀粉与添加氨基酸的淀粉的m值均小于1,表明淀粉及其氨基酸混合物都属于假塑性流体,并且Lys使淀粉假塑性增强,而Asp则相反。

茄子雄性不育系的可溶性糖、淀粉、氨基酸分析

以2个不同品种茄子雄性不育系及其保持系为试材,对不同发育阶段花蕾中可溶性糖、淀粉、游离氨基酸和脯氨酸含量进行了比较研究。结果表明:随着花蕾的发育,不育系可溶性糖高于其保持系;不育系淀粉含量变化不大;保持系淀粉含量在减数分裂时期达到最高,小孢子时期又迅速下降,其后缓慢上升。此外,不育系游离氨基酸和脯氨酸含量均低于保持系。

糙米发芽过程中营养成分及植酸含量变化的研究

研究了Ⅱ优838、川香优2号、江镇粳糯和香粳99糙米在35℃下发芽60h内其营养成分和植酸含量的变化。结果表明,4个品种糙米在发芽过程中淀粉和植酸含量均呈下降趋势,其他营养成分先上升后下降。4个品种糙米在发芽24h时抗坏血酸含量最高。赖氨酸含量约为发芽前的3倍左右,除江镇粳糯在发芽24h最高外,其余3个品种均在发芽36h达到峰值。色氨酸含量除Ⅱ优838在发芽48h最高外,其余3个品种在发芽36h达到峰值,约是发芽前的2倍左右。Ⅱ优838和川香优2号糙米可溶性蛋白、游离氨基酸和还原糖的含量在发芽36h达到峰值,江镇粳糯和香粳99的峰值则出现在发芽48h。发芽后可提高糙米营养成分的含量,降低其抗营养因子植酸的含量,有利于糙米品质的改善。

氨基淀粉絮凝剂合成工艺

以玉米淀粉为原料 ,以环氧氯丙烷 (ECH)作交联剂 ,合成高交联淀粉 (CS) ;以HClO4作引发剂 ,以ECH作醚化剂 ,合成中间产物 3 氯 2 羟基丙烯基交联淀粉 (CHCS) ,在碱性条件下再与乙二胺反应 ,得到对重金属离子具有螯合能力的氨基淀粉 (CAS)。最佳醚化条件 :CS含水质量分数为 7.0 % ,ECH与CS的摩尔比为 2 .5∶1,HClO4与CS的摩尔比为 0 .0 3∶1,反应时间为 8h ,反应温度为 95℃。以该法制得的CAS对废水中铜离子的去除能力为 78.5mg/g。

高寒地区牧草碳水化合物及氨基酸含量季节动态研究

对高寒地区13种牧草碳水化合物(可溶性糖、淀粉)和氨基酸(总游离氨基酸、赖氨酸)含量进行研究。结果表明,球花蒿、高山龙胆、禾草、珠芽蓼和黄花棘豆5种牧草可溶性糖、淀粉、总游离氨基酸、赖氨酸含量随季节呈单峰曲线变化,其最高值和最低值分别出现在6或7月和12或1月;6月13种牧草可溶性糖和淀粉含量不同,变化幅度在0.55%～2.05%,7月8种牧草游离氨基酸和赖氨酸含量变化幅度分别在0.36%～1.37%和0.14%～1.11%;同一时期部分牧草草地来源不同,可溶性糖、淀粉、总游离氨基酸和赖氨酸含量差异显著,部分牧草则差异不显著;淀粉比可溶性糖、总游离氨基酸和赖氨酸更易受环境因子的影响,且它们之间并不一定成正相关性。

高温高湿处理对小麦籽粒蛋白质、氨基酸及糖类含量的影响

分析了短时间高温高湿处理对小麦蛋白质、氨基酸及糖类含量的影响。结果表明,24 h的高温(≥35℃)和高湿度(RH 80%)处理,与常温保存和30℃、RH 60%处理比较,增加了小麦籽粒的电导率、谷氨酸(G lu)及总氨基酸的含量,但降低了水溶性糖、醇溶性糖及醇溶性蛋白的含量,导致小麦籽粒干物质含量呈下降趋势。随着储藏温度和相对湿度的增加,天冬氨酸(Asp)、苏氨酸(Thr)、丝氨酸(Ser)、赖氨酸(Lys)及精氨酸(Arg)的含量增加,对应的球蛋白和清蛋白含量呈增加趋势。异亮氨酸(Ile)含量减少,对应的醇溶蛋白减少。谷氨酸和脯氨酸(Pro)含量增加,相应的麦谷蛋白含量也增加。高分子质量蛋白质的巯基被氧化形成二硫键,增大了麦谷蛋白质与醇溶蛋白质之间的比率。小麦品种对高温高湿储藏条件的反应受原产地影响。