氧化工艺对氧化淀粉性能的影响研究

为研究应用不同氧化剂制备的氧化淀粉性能的差异,分别对应用次氯酸盐和过氧化氢制备的氧化淀粉的性能进行了测试、对比.通过测试两种氧化工艺所制备的氧化淀粉的溶液性能、浆膜性能和浆纱性能,得知:采用次氯酸钠制备的氧化淀粉的浆膜强伸性能和浆纱性能优于采用过氧化氢制备的氧化淀粉,说明采用次氯酸钠制备的氧化淀粉更适用于经纱上浆.     

Oxidation of Starch Catalyzed by Persulfate

Oxidation of unmodified corn starch in the presence of persulfates under different conditions has been studied. The method using silver catalyzed persulfate led to a grey colored oxidation product containing equal carbonyl but less carboxyl contents as compared to an industrial oxidized starch sample. Air-oxidation of starch in the presence of persulfate gave a colorless oxidation product possessing low carboxyl but high carbonyl contents. Irradiation, by ultraviolet light during this oxidation procedure had little effect on the degree of oxidation. Ammonium persulfate was found to be a better oxidant than potassium persulfate.     

Oxidation of Potato Starch by Hydrogen Peroxide

Potato starch was oxidized by hydrogen peroxide in alkaline and acidic reaction conditions with copper, iron and tungstate catalysts in order to introduce carboxyl and carbonyl groups to the starch molecule. Carbonyl contents up to 6.6 per 100 glucose units could be obtained, whereas carboxyl content remained low (up to 1.4). Starch yields in the alkaline and acidic reactions were 90 and 99%, respectively. The molecular weight decreased markedly with the degree of oxidation, and was dependent on the catalyst used. Rheological measurements revealed that when the molecular weight of the moderately oxidized starch was high, a very firm gel (G' = 40kPa) was obtained with 25% starch concentration. When the degree of oxidation increased, the storage modulus G' decreased. The more the oxidized starch contained carbonyl groups, the higher was the gelatinization temperature.     

拟均相两段工艺氧化法制备双醛淀粉

以绿豆淀粉为原料,NaIO4为氧化剂的拟均相两段工艺制备双醛淀粉(dialdehyde starch,DAS),考察预处理阶段中温度、酶处理、超声活化和氧化阶段中反应温度、反应时间、pH值、投料比、NaIO4浓度、淀粉乳浓度、相转移催化剂对制备双醛淀粉的影响,前段的预处理采用超声活化处理,后段的氧化工艺考察相转移催化剂的影响,并用正交法对制备双醛淀粉的工艺进行优化。结果表明：在以醛基含量为考察指标,预处理时不宜用酶,处理温度50～60℃,经30℃、40W、40kHz超声活化淀粉乳30min能有效提高淀粉与NaIO4的氧化反应活性,制得高醛基含量的DAS。相转移催化剂对提高产品醛基含量有一定作用。经正交试验优化得到的最佳条件为：以十六烷基三甲基氯化铵为相转移催化剂、反应时间2h、反应温度40℃、n(NaIO4):n(淀粉)=1.0:1.0、NaIO4浓度0.5mol/L、淀粉乳质量分数10%、体系pH2,在此条件下,制得的DAS双醛含量为96.81%。经光谱和理化性能等指标的检测证实所得的DAS与文献报道的DAS相符合。     

Oxidation of Maltodextrins and Starch by the System Tungstate-Hydrogen Peroxide

The potential of the aqueous system sodium tungstate-hydrogen peroxide for glycol-cleavage oxidation of maltodextrins, starch and trans-1,2-cyclohexanediol as a model compound has been evaluated. The peroxotungstate species formed in this medium effect oxidation of the glucose units via two major pathways: (i) glycol-cleavage of the C2–C3 diol moieties in internal glucose units, followed by (undesired) hydrolysis of the ring-opened intermediate and (ii) stepwise decarboxylation at the reducing terminal glucose unit until the glycosidic bond is reached. Both reaction types yield glucose oligomers terminated by erythronic acid at the former reducing end, which is an important fraction (up to 40%) of the oxidation product. Decomposition of hydrogen peroxide to oxygen and water is an inevitable side reaction.     

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。     

羧甲基化氧化淀粉胶粘剂的研究

以玉米淀粉为原料,在常压下,采用氧化和醚化相结合的改性方法.合成羧甲基氧化淀粉胶粘剂.用正交试验法对影响产物牯度和粘合强度的因素进行了研究,并对反应条件进行了优化.结果表明,氢氧化钠和淀粉的用量对产物粘合强度的影响最大.其次是过氧化氢、硫酸铜和一氯乙酸,硼砂和温度的影响相对较小;而过氧化氢的用量对产物粘度的影响最大,其次是温度、硼砂、一氯乙酸、硫酸铜、氢氧化钠.淀粉的用量对产物粘度的影响相对较小;优化的工艺参数为淀粉8.5～9 g,30%氢氧化钠3.2 ml,硫酸铜0.01 g,30%过氧化氢0.06 ml.硼砂0.06 g,一氯乙酸0.04 g,温度50℃.     

羧甲基化氧化淀粉胶粘剂的研究

以玉米淀粉为原料，在常压下，采用氧化和醚化相结合的改性方法．合成羧甲基氧化淀粉胶粘剂。用正交试验法对影响产物粘度和粘合强度的因素进行了研究，并对反应条件进行了优化。结果表明，氢氧化钠和淀粉的用量对产物粘合强度的影响最大．其次是过氧化氢、硫酸铜和一氯乙酸，硼砂和温度的影响相对较小；而过氧化氢的用量对产物粘度的影响最大，其次是温度、硼砂、一氯乙酸、硫酸铜、氢氧化钠，淀粉的用量对产物粘度的影响相对较小；优化的工艺参数为：淀粉8．5～9g，30％氢氧化钠3．2ml，硫酸铜0．01g，30％过氧化氢0．06ml，硼砂0．06g，一氯乙酸0．04g，温度50℃。     

Hypochlorite Oxidation of Barley and Potato Starch

The oxidation of barley and potato starches was studied using sodium hypochlorite as oxidant. The degree of oxidation, depolymerization during oxidation and gel formation of barley starch was compared with the properties of potato starch. The effect of oxidation on gelatinization of starches as well as on amylose-lipid complex of barley starch was also analyzed. Barley starch was not as easily oxidized as potato starch. In both starches depolymerization of amylopectin and amylose occurred during oxidation. Based on the dissociation enthalpy of amylose-lipid complex, the lipid-bound amylose in barley starch was readily oxidized. Oxidation decreased the gelling ability of barley starch. At high level of oxidation gel formation by potato starch was much slower and weaker than by barley starch.     

芭蕉芋淀粉的催化氧化

本文探讨了催化剂的种类、次氯酸钠的用量和反应时间对芭蕉芋淀粉氧化反应的影响.结果表明:氧化淀粉中的羧基随次氯酸钠的用量和反应时间的增加而增加,但粘度不断下降.有效氯为2%时,淀粉中羰基含量最高.使用催化剂A可制备羧基和羰基含量都较大的氧化淀粉,使用KI则可制备羧基少而羰基含量高的氧化淀粉.     

红薯淀粉与绿豆淀粉复配粉条的工艺研究

用天然高直链淀粉含量的绿豆淀粉与红薯淀粉复配生产粉条,对其调粉团工艺、老化低温时长进行单因素及正交试验,以断条率、透光率、剪切力、拉伸力、感官评价为评价指标,以加权综合评分为依据,筛选最佳工艺条件。结果:当绿豆淀粉添加量40%、加芡量6%、含水量40%,冷藏4 h、冷冻8 h所得粉条,烹煮品质及感官品质最佳;相比传统的纯红薯粉条,复配粉条顺滑透亮、不易糊汤与断条、口感细腻不黏牙;无污染、更节能。     

山药淀粉加工特性研究

采用水磨法制备山药淀粉,以马铃薯淀粉和玉米淀粉为对照,比较系统地研究山药淀粉的颗粒特性和糊化特性。结果表明,山药淀粉颗粒多为扁卵圆形,颗粒大小在8～30μm之间,长轴平均粒径为20μm;偏光十字中心偏向一边,呈"X"型。山药淀粉溶解度和膨胀度明显小于玉米淀粉和马铃薯淀粉。与对照相比,山药淀粉糊具有较低的透明度,较差的冻融稳定性。山药淀粉起糊温度较高,糊的热稳定性好,抗剪切能力强。增加淀粉质量分数和pH,淀粉糊冷热稳定性降低。添加蔗糖、NaCl和Na2CO3,提高了山药淀粉的起糊温度,增强热稳定性,提高抗剪切能力,但添加明矾使糊热稳定性降低,抗剪切能力下降。除蔗糖外,NaCl、Na2CO3、明矾添加剂对山药淀粉的糊化特性影响明显。     

Coupling of 1-Aminododecan to Starch by Bromine Oxidation and Reductive Amination

Conjugates of potato starch have been prepared by coupling of bromine oxidized starch to 1-aminododecan by reductive amination. The starch was oxidized at two different levels of molar ratios bromine/starch (1/20 and 1/5) and at two different temperatures (22deg;C and 94deg;C). The content to introduced keto functions was highest for the 1/5 sample oxidized at 22deg;C. The GPC (gel permeation chromatography) analyses of the molecular weight showed that oxidation 1/5 at 94deg;C provided an oxidized starch with molecular weight below 50,000 whereas the other oxidation conditions gave products with higher molecular weights. The keto functions of the oxidized starch was aminated with 1-aminododecan by reductive amination at different temperatures (22deg;C and 80deg;C) and reaction times. The proportion of coupled amine was highest at 80deg;C after 3 h.     

ClO_2制备食用马铃薯氧化淀粉工艺研究

选用新型、安全、高效、稳定的氧化剂制备马铃薯氧化淀粉,通过工艺参数优化实验确定其工艺参数最优水平为:ClO2用量为淀粉质量的0.12%(以ClO2计),LXF型专用活化剂为ClO2原液的10%,反应时间5 h,反应温度50℃。     

Impact of Radiation Processing on Starch

ABSTRACT: It is envisaged that there will be a considerable demand in the near future for modified starches. To meet the demand, the chemical modification of starch, including cross‐linking, has been widely used to obtain desirable traits that are suitable for various food applications. Radiation processing, being a physical process, is an environmentally friendly alternative to chemical modification. It is economically viable, safe, and possesses several advantages over other conventional methods employed for modification and cross‐linking. Irradiation of starch leads to the attainment of such desired functional attributes as reduction of viscosity, high water solubility, and others. This review provides insight into the impact of gamma, electron beam, and ultraviolet irradiation on the physicochemical and functional properties of starch. It also highlights the importance and the exciting new opportunities afforded by radiation treatments as a physical means for the modification of starch.     

接枝氧化淀粉工艺条件的优化

探讨能替代PVA的接枝变性淀粉的生产工艺条件。以氧化玉米淀粉为原料、过硫酸铵为引发剂、乙酸乙烯酯和丙烯酸丁酯为单体进行接枝共聚反应,并将所制得的接枝变性淀粉用于T/C 65/35 13 tex纱的上浆,用正交试验法探讨了引发剂用量、单体用量、反应时间、反应温度对浆纱耐磨性能、断裂强力、毛羽的影响试验得出最优工艺条件为过硫酸铵用量为单体总量5.5%,乙酸乙烯酯:丙烯酸丁酯为4:6,反应温度为55℃,反应时间为3.00h。认为在优化条件下制得的接枝变性淀粉浆料具有较好的上浆性能,可替代PVA用于涤棉混纺纱的上浆。     

酶解法制备荞麦抗性淀粉的工艺优化

为确定荞麦粉制备抗性淀粉的工艺条件,采用普鲁兰酶酶解脱支法,并通过单因素和正交试验研究了影响抗性淀粉得率的因素。结果表明：影响抗性淀粉得率的因素主次顺序依次为荞麦粉浓度、普鲁兰酶用量、酶解时间和酶解温度。酶解法制备荞麦抗性淀粉的适宜工艺条件为荞麦粉浓度5 g/（100 mL）、普鲁兰酶用量7.2 PUN/g、酶解温度45℃、酶解时间8 h,在此条件下测得的抗性淀粉含量为15.82%。与原粉相比,普鲁兰酶酶解脱支与湿热法相结合制备荞麦抗性淀粉使其抗性淀粉含量显著提高。     

Transformations of Potato Starch During Oxidation with Hypochlorite

Five starch samples of different degree of oxidation were obtained with the help of sodium hypochlorite. Apart from that, commercial starch was divided into 3 fractions of differentiated size of grains and the fractions were also subjected to oxidation. The analysis of oxidized starch led to following results:

• large grains of starch undergo the oxidation process more easily than small grains, from oxidized starch hydrolysates glucuronic acid amounting to about 75% of carboxyl groups and gluconic acid to about 25% of carboxyl groups, can be separated;
• side reaction proceeding during oxidation process is hydrolytic degradation of starch molecules which is shown by the increase of reducing value and the decrease of viscosity of oxidized starch;
• in starch oxidized with hypochlorite absence of dialdehyde systems is characteristic in contrast to starch oxidized with periodate;
• in the process of oxidation with hypochlorite, starch molecules change their shape and spatial system, which is indicated by the changes of colour complexes with iodine, greater resistance to the action of amylolitic enzymes and greater capacity for forming flexible gels in the form of films.