纳米微晶纤维素-NaClO氧化淀粉的制备及其对纸张性能的影响

本研究在质量分数为30%的淀粉乳液中加入纳米微晶纤维素(NCC)与Na ClO于50℃恒温条件下制得NCC-NaClO氧化淀粉,并探究了NCC添加量对淀粉氧化程度的影响,再利用傅里叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)对氧化淀粉进行了表征,并探讨了氧化前后淀粉用作纸张表面施胶剂和浆内添加剂对纸张强度性能的影响。结果表明,添加NCC能有效提高淀粉的氧化效果,当NCC用量为0. 5%(以绝干淀粉质量计)时,NCC-NaClO氧化淀粉的羧基含量为1. 10%,NCC-NaClO氧化淀粉表面施胶量为2 g/m~2时,纸张表面接触角为82. 5°,可作为纸张表面施胶剂使用; NCC-NaClO氧化淀粉用量为0. 75%时,可明显改善纸张的强度性能。     

双氧水对淀粉氧化程度影响的研究

双氧水氧化淀粉可得到高纯度产品,过量的双氧水最终分解为水,不会影响产品的纯度,更不会影响环境,是一个较为理想的绿色工艺。通过正交实验在不同条件下研究双氧水对淀粉氧化程度的影响,发现pH值是控制氧化程度的决定因素,并且可知氧化淀粉羧基含量较多的最佳工艺条件为：pH=9．0,双氧水用量8％,反应温度50℃,反应时间3h,催化剂用量0．1％;氧化淀粉羰基含量较多的最佳工艺条件为：pH=3．0,双氧水用量8％,反应温度50℃,反应时间3h,催化剂用量0．1％。     

催化氧化制备氧化淀粉

研究了以Cu^2＋为催化剂、双氧水为氧化剂，玉米淀粉经氧化处理后羧基含量和粘度的变化，考察了催化剂用量、反应时间、反应温度和反应pH值对结果的影响。实验结果表明：选用Cu^2＋作催化剂，最适合反应条件为催化剂用量0．02％（淀粉干重）、反应温度45℃、反应时间4．0h、反应pH7．0。在此催化条件下，双氧水用量20mL，可制得羧基含量为1．21％的氧化淀粉。     

阳离子淀粉作为表面施胶剂的研究

本文的研究目的是为了满足市场对增加纸张内部和表面强度,改善印刷性能和提高纸张强度的需求,采用将木薯淀粉阳离子化原纸进行表面施胶,然后测定纸张性能,探讨阳离子淀粉作为表面施胶剂的最佳应用条件。本文探讨了阳离子淀粉用作纸张表面施胶剂的作用机理,初步研究了制备阳离子淀粉的最优化条件,不同取代度的阳离子淀粉作为表面施胶剂的应用效果。通过对纸张性能（抗张强度、环压强度、吸水性）的测定,找出阳离子淀粉应用的优点。实验结果表明制备阳离子淀粉的最优化条件为木薯淀粉用量为50g,阳离子醚化剂用量为3.008g,n（NaOH）：n（CTA）=1.2：1,反应时间为2h,反应温度为40℃;阳离子淀粉作为表面施胶剂的最佳取代度和固含量分别为0.056和40%。     

芭蕉芋氧化淀粉的制备与性质

采用正交法考察了淀粉悬浮液浓度、过氧化氢与催化剂用量、反应温度和反应时间对芭蕉芋过氧化氢氧化淀粉中羧基含量的影响,并比较了相同氧化剂用量下次氯酸钠、高锰酸钾、过氧化氢氧化淀粉的羧基含量和黏度。结果表明,制备芭蕉芋过氧化氢氧化淀粉的最佳反应条件为pH=7,淀粉悬浮液浓度46％,过氧化氢12％,硫酸铜0．048％,反应时间3h,反应温度50℃,在此条件下,制备的氧化淀粉羧基含量可达0．92％;次氯酸钠氧化效率高于过氧化氢和高锰酸钾;低羧基含量时次氯酸钠氧化淀粉的黏度大于过氧化氢和高锰酸钾氧化淀粉。     

玉米、木薯氧化淀粉性能及对纸张的施胶效果

本文分别以木薯淀粉和玉米淀粉为主要原料,以H2O2为氧化剂,在相同条件下制备了两种氧化淀粉,研究这两种氧化淀粉性能差别及作为施胶剂对纸张施胶效果的影响.     

氧化糯玉米淀粉的制备及性能研究

以糯玉米淀粉为原料,以次氯酸钠为氧化剂,氢氧化钠为催化剂,对氧化糯玉米淀粉的制备及性能进行了研究.考察了反应时间、反应温度、次氯酸钠用量、pH对氧化糯玉米淀粉羧基含量的影响,采用酸碱滴定法测定氧化糯玉米淀粉羧基含量.试验结果表明,随着次氯酸钠用量增加,氧化糯玉米淀粉的羧基含量也随之增大;在一定时间范围内,氧化糯玉米淀粉的羧基含量随反应时间的增加而增加;反应温度和pH对氧化糯玉米羧基含量的影响呈倒抛物线趋势,存在最大值.糯玉米淀粉经氧化后,其液透明度和黏度热稳定性提高,但其冻融稳定性和凝沉性下降.     

TEMPO/NaBr/NaClO体系氧化酶解淀粉及其表面施胶

用α-淀粉酶对玉米原淀粉进行酶解预处理,酶解后的淀粉再通过2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)氧化体系进行改性,并将改性后的淀粉用作造纸表面施胶剂。研究发现,在pH值9.5、温度5℃、反应时间2.0 h、TEMPO用量1.0 mg/g、NaBr用量0.01 g/g、NaClO用量2.00 mmol/g的条件下,TEMPO/NaBr/NaClO体系氧化酶解淀粉可使改性淀粉的羧基含量为5.06%;将改性淀粉作为表面施胶剂,当表面施胶量为4 g/m2时,与未施胶原纸相比,纸张抗张强度和表面强度的增幅分别为51.6%和334%。     

制备易消化氧化淀粉工艺条件的研究

本论文研究了不同条件对生成易消化氧化淀粉的影响。试验表明,以马铃薯淀粉为原料,NaClO为氧化剂时影响羧基含量和消化性能的因素中,以NaClO的影响最显著。通过正交试验确定了制备消化性能好的氧化淀粉的最佳工艺条件为:次氯酸钠用量3%,反应时间2h,反应温度30℃,pH10。通过研究氧化淀粉的羧基含量与消化性能的关系,发现其在一定范围内呈正相关性。     

糊化活化淀粉的制备及其活性基团含量的测定

氧化组分1与氧化组分2在适当的配比下构成的双组分氧化体系能产生良好的协同作用，可以将糊化后的可溶性淀粉活化成具有较多活性基团的糊化活化淀粉。经过糊化后活化的淀粉，含有更多的活性基团，从而增加了后续反应的活性。由正交实验可以看出，得到含羧基量较多的糊化活化淀粉最佳反应条件为pH值3．0；氧化组分1用量4％；温度85℃；时间4h。而得到含羰基量较多的糊化活化淀粉最佳反应条件为pH值5．0；氧化组分1用量12％；温度95℃；时间2h。并且J值也远远小于I值，表明所得到的含羰基量远远多余含羧基量，得到含羰基量较多的糊化活化淀粉的反应条件要相对容易控制。并且得到的含羰基糊化活化淀粉可以与蛋白质的氨基之间形成交联，可作为淀粉填料的中间产品。     

氧化淀粉对面条品质的影响研究

应用氧化淀粉对面条品质进行改良研究,详细研究了不同添加量和不同氧化度的氧化淀粉对面团的流变学性能、面条的拉伸性能、弯曲断条率、蒸煮断务率、吸水率、溶出率及面条的感官品质等的影响,探讨了氧化淀粉对面条品质影响的机理。     

Characterization of Different Starches Oxidized by Hypochlorite

The effects of starch origin (potato, corn, and rice starches) and hypochlorite level (NaOCl, 0.8% and 2% w/w) on the structures and physicochemical properties of oxidized starches were investigated. Carboxyl and carbonyl group contents of oxidized starches increased with increasing NaOCl level, with potato starch having the highest and corn starch having the lowest carboxyl groups content at both NaOCl levels. Oxidation generally reduced the pasting temperature and viscosity of native starches as demonstrated by using a Rapid Visco Analyser. The peak viscosities of oxidized rice and corn starches were higher than those of their native counterparts at 0.8% NaOCl. The morphology of starches was not altered and X‐ray diffraction patterns of all the starches remained unchanged after oxidation. Oxidized starch batters exhibited greater adhesions than did native starch batters, with rice starch batter exhibiting the greatest adhesion. Carbohydrate profiles by high‐performance size‐exclusion chromatography indicated that both amylopectin and amylose were degraded during oxidation. The level of oxidation was largely dependent on the degree of crystallinity of starch and the degree of polymerization of amylose, whereas the adhesion property of oxidized starch was mainly attributed to its granular size and shape.     

Binding of amino acids to hypochlorite‐oxidized potato starch

Novel starch derivatives were prepared by derivatization of oxidized potato starch with amino acids in aqueous suspension. Potato starch was oxidized using sodium hypochlorite and then reacted with amino acids under mildly alkaline conditions. By analysis of increased nitrogen content and by means of confocal laser scanning microscopy, efficient binding of positively charged amino acids to oxidized starch molecules was confirmed. A degree of substitution (DS) of up to 0.015 was obtained using oxidized starch (degree of oxidation (DO) of up to 1.0%) and positively charged amino acids (2–5%, dry starch basis) at reaction conditions of starch/water ratio of 1:2–2.5, pH 10, 40°C, 30–60 min. The DS was positively correlated with the DO of the starch. Derivatization of oxidized starch using amino acids generally enhanced the influence of oxidation on starch pasting characteristics, perhaps showing interesting functional properties and potential industrial application.     

响应面法优化氧化辛烯基琥珀酸甘薯淀粉酯的制备工艺

以氧化甘薯淀粉(oxidation sweet potato starch,OSPS)为原料,制备氧化辛烯基琥珀酸甘薯淀粉酯(octenyl succinate anhydride-oxidation sweet potato starch,OSA-OSPS)。运用响应面分析(response surface method analysis,RSA)辛烯基琥珀酸酐(octenyl succinate anhydride,OSA)添加量、pH值、温度和时间对OSA-OSPS取代度(degree of substitution,DS)的影响,得出最佳制备工艺：酸酐添加量7%、pH8.40、温度40℃,反应时间10h。采用快速黏度分析仪(rapid viscosity analyzer,RVA)分析表明：氧化甘薯淀粉峰值黏度较低,而经过OSA酯化后,峰值黏度又会有一定程度的提高,且随DS的增加呈上升趋势。     

Hypochlorite oxidation of field pea starch and its suitability for noodle making using an extrusion cooker

The effect of hypochlorite oxidation on the Brabendar pasting properties of field pea starch and the suitability of native and oxidized starch for noodle making by extrusion cooking were investigated. Field pea starch was oxidized with sodium hypochlorite at a level of active chlorine ranging from 0.89 to 3.28% (starch db). The degree of oxidation was determined and expressed in terms of percentage of carboxyl and carbonyl groups, which ranged from 0.02 to 0.38% and 0.06 to 0.19%, respectively. Starch recovery and peak viscosity, hot paste viscosity, cool paste viscosity, and setback of oxidized starches decreased with increasing degree of oxidation. The cooking quality attributes of noodles prepared from native field pea starches were acceptable but were negatively influenced by hypochlorite oxidation. Substitution of potato starch (40%, db) for field pea starch yielded more glossy noodles with better cooking quality. It was also observed that Brabendar pasting properties had high correlations with noodle quality characteristics.     

马铃薯淀粉氧化工艺优化研究

以芬顿试剂为氧化剂氧化马铃薯淀粉,研究pH、氧化温度、氧化时间、30%H2O2用量和FeSO4用量等单因素对氧化淀粉中羧基含量的影响。在此基础上,采用Box-Behnken优化淀粉氧化工艺条件,建立并分析了各因素与含量关系的数学模型。单因素实验结果表明氧化时间4h,30%H2O2用量为25mL,pH10,温度为50℃,FeSO4用量0.3g。响应曲面分析得到在30%H2O2用量为25mL,pH=10和氧化温度为50℃的条件下,氧化淀粉中羧基含量为1.4590%,与理论值1.4699%接近。说明回归模型能较好的预测氧化淀粉中羧基含量。SEM表明淀粉颗粒经过芬顿试剂氧化后表面出现孔洞;IR表明有羧基的特征吸收峰出现。     

Effect of oxidation and esterification on functional properties of mung bean (Vigna radiata (L.) Wilczek) starch

The chemical and physicochemical properties of mung bean starch oxidized by sodium hypochlorite and esterified with succinic anhydride were studied. Mung bean starch was modified by oxidation with sodium hypochlorite and esterified with succinic anhydride. The native mung bean starch (NMBS) granules were shown to have an irregular shape, which varied from oval to round to bean shape with a smooth surface. Succinylation led to partial rupture of the granule integrity while oxidation converted the smooth surface of the native granules to a surface with fissures. Swelling capacity improved through succinylation but was reduced after oxidation. Oxidation enhanced solubility; however, succinylation showed no uniform effect throughout the temperature range studied. Both modifications increased hydrophilic tendency and demonstrated decreased gelatinization temperature compared to the NMBS. Oil absorption capacity and syneresis of native starch was enhanced after oxidation but was reduced after succinylation. Both starch types, native and modified, exhibited non-Newtonian behavior, but to a different extent. The gel formation of oxidized starch revealed the highest storage modulus followed by native starch and then succinated starch.     

High Carbonyl Content Oxidized Starch Prepared by Hydrogen Peroxide and Its Thermoplastic Application

Hydrogen peroxide was used to oxidize gelatinized starch to oxidized starch (OS) with degree of oxidation (DO) ranging from 0.096 to 0.554 depending on the H₂O₂/starch molar ratios used. Then glycerol was added to OS to produce thermoplastic oxidized starches (TPOS). Titrimetric determination of carboxyl and carbonyl groups, FT‐IR, ¹H‐NMR and ¹³C‐NMR confirmed that at H₂O₂/starch molar ratios < 0.7, oxidized starch contained much more aldehyde than carboxyl groups, while at molar ratios up to 2.0, peroxide oxidation produced mainly carboxyl groups. Scanning electron microscopy (SEM) revealed that the oxidized starch particles (at DO 0.385) obtained a porous structure. The effect of DO on the structure and properties of OS, as well as mechanical properties and moisture resistance of TPOS was studied, respectively. With an increase in DO, the crystallinity, intrinsic viscosity and thermal stability of OS decreased markedly, the ability of OS to take up water decreased at low DO and increased at higher DO. These observations show that hydrogen peroxide can be used to oxidize starch in a controlled way. TPOS with DO 0.385 showed the best mechanical properties, its tensile strength was 6.1 MPa after placing in 100% relative humidity for 15 days.     

氧化-乙酰化复合变性淀粉的乳化性能

淀粉基乳化剂具有原料来源广泛、天然安全和产品配伍性能好的优点,在食品工业中具有较好的应用和发展前景。文中以玉米淀粉为原料,通过氧化和乙酰化双重变性,研究了变性淀粉的糊化和乳化特性。研究表明,深度氧化对乙酰化具有一定的抑制作用;当样品的变性剂添加量之比(乙酸酐/次氯酸钠)在1.33～2.67时,可获得羧基含量为0.26%并且乙酰基/羧基比值在1.64～3.03的氧化-乙酰化淀粉,该淀粉质量浓度为6%时糊黏度在273～295 mPa.s,具有较优的乳化性能。     

Production and characterization of oxidized cassava starch (Manihot esculenta Crantz) biodegradable films

Plastic is one of the most common pollutants in the environment. Therefore, the number of studies on the use of biodegradable packaging is increasing. Starch is the primary material used in the production of biodegradable plastics due to its natural abundance and high biodegradability. Yet, the strong hydrophilic character of starch presents a challenge. Therefore, the modification of its structure through oxidation may yield interesting results as the viscosity reduction. The objectives of this work were to obtain cassava (Manihot esculenta Crantz) starch oxidized with 0.8 and 2.0% active chlorine, to develop biodegradable films and characterize their mechanical properties, solubility in water, permeability to water vapor, degree of swelling, and sorption isotherms. Biodegradable films were produced with starch concentrations of 2, 3, 4, and 5% w/w and 25% glycerol (g/100 g starch) added as a plasticizer. Images of the films were obtained with an atomic force microscope and allow to observe a smooth surface and the absence of starch granules in the film produced with oxidized starches. The tensile strength of the biodegradable film produced with oxidized starch (0.8% active chlorine) was 80 MPa. The value of permeability to water vapor was 1.613 × 10⁻⁹ kg/day/m/Pa, and the average solubility was 41%. The sorption isotherms showed that biodegradable films made with oxidized starches cannot be used in environments with relative humidity below 35% or above 90%.