不同直链淀粉含量对羟丙基氧化玉米淀粉性质的影响

本文采用蜡质玉米、普通玉米和高直链玉米淀粉为原料,改变有效氯添加量,制备羟丙基氧化淀粉,通过XRD、DSC、Brabender粘度仪等测定手段,研究不同直链淀粉含量对羟丙基氧化淀粉理化性质的影响。实验表明,直链淀粉含量对羟丙基化和氧化程度影响显著,其中直链淀粉含量高有利于羟丙基化,而不利于氧化;X-射线衍射分析发现,改性淀粉没有改变晶型,随氧化程度增加,淀粉分子结晶度下降,直链淀粉含量越高,下降趋势越缓;DSC测试和Brabender粘度分析表明,直链淀粉含量直接影响到羟丙基氧化淀粉糊化特性,糊化温度:高直链普通蜡质,糊粘度:蜡质普通高直链,糊化焓:蜡质普通高直链;通过观察淀粉的偏光特性和颗粒表面形态,发现直链淀粉含量越高,羟丙基氧化淀粉的偏光十字越弱,颗粒越不易破碎。     

玉米羧甲基淀粉对馒头品质及老化特性的影响

以甲醇为溶剂制备玉米羧甲基淀粉,将玉米羧甲基淀粉添加到馒头粉中,研究了玉米羧甲基淀粉对馒头品质及老化特性的影响。结果表明：添加玉米羧甲基淀粉使馒头比容降低、色泽变暗,馒头的感官评分降低,但添加适量的羧甲基淀粉能显著改善馒头的内部组织结构。当添加量为0.5%时,玉米羧甲基淀粉能有效地抑制馒头的老化。     

变性淀粉对玉米饮料稳定性的影响

将变性淀粉作为稳定剂添加至玉米饮料中以提高玉米饮料的稳定性。采用单因素和正交试验研究3种变性淀粉对玉米饮料稳定性的影响。结果表明:向玉米饮料中添加0.8%羟丙基复合变性淀粉、0.8%乙酰化变性淀粉和0.6%羟丙基辛烯基琥珀酸酯化淀粉,可以提高玉米饮料的稳定性,降低其离心沉淀率。对玉米饮料混浊稳定性和离心沉淀率效果影响主次顺序为:羟丙基复合变性淀粉,羟丙基辛烯基琥珀酸酯化淀粉,乙酰化变性淀粉。     

羟丙基氧化高直链玉米淀粉的制备、表征及性能研究

以高直链玉米淀粉为原料,次氯酸钠为氧化剂,环氧丙烷为醚化剂,氢氧化钠为催化剂,对羟丙基氧化高直链玉米淀粉的制备、表征及性能进行了研究。考察了环氧丙烷用量、羟丙基化时间、羟丙基化温度、氢氧化钠用量和无水硫酸钠用量对羟丙基氧化高直链玉米淀粉取代度的影响。结果表明,制备氧化高直链玉米淀粉的较佳工艺条件为:羟丙基化时间18h、羟丙基化温度40℃、无水硫酸钠用量10%、氢氧化钠用量1.2%。高直链玉米淀粉经氧化后,在波数1 735cm-1处出现CO的伸缩振动峰;羟丙基化、氧化改变了高直链玉米淀粉热稳定性。氧化、羟丙基化能提高高直链玉米淀粉的冻融稳定性和膨胀能力,氧化使高直链玉米淀粉蓝值降低,羟丙基化基本不改变高直链玉米淀粉的蓝值。     

三种羟丙基二淀粉磷酸酯对木薯淀粉特性的影响

为了研究三种羟丙基取代度相同、交联程度不同的羟丙基二淀粉磷酸酯（HDP）对木薯淀粉（TS）特性的影响，本文测定了三种羟丙基二淀粉磷酸酯的交联度，进行了淀粉糊液状态观察，在木薯淀粉中分别添加三种羟丙基二淀粉磷酸酯后，测定淀粉体系的冻融稳定性，并通过透明度测定、质构分析（TPA）和差示扫描量热法（DSC）对三种羟丙基二淀粉磷酸酯的添加对木薯淀粉老化性质的影响进行了研究。研究发现，添加三种羟丙基二淀粉磷酸酯均降低了木薯淀粉的析水率；在4℃储存过程中，添加羟丙基二淀粉磷酸酯后，木薯原淀粉的硬度有所改善，其透明度下降速率变缓，熔融焓值（ΔH）降低。三种羟丙基二淀粉磷酸酯的添加均改善了木薯淀粉的冻融稳定性，抑制了木薯淀粉的老化，而交联度较高的两种羟丙基二淀粉磷酸酯效果更佳。     

玉米淀粉与玉米变性淀粉性质比较研究

测定了玉米淀粉、羟丙基淀粉、羧甲基淀粉、淀粉磷酸酯的冻融稳定性、透光率、膨胀度、粘度、糊化特性等主要物理性质并进行了比较。试验结果表明：变性淀粉与玉米淀粉的性质不同，由于变性淀粉引进了羟丙基、羧甲基、磷酸基团等亲水性基团，使淀粉极性增强，亲水能力增大，使其都具有较强的冻融稳定性、抗凝沉性，较高的膨胀度、透明度，因此变性淀粉具有更广阔的应用性。     

蜡质玉米变性淀粉对番茄沙司储藏稳定性的影响研究

文章对比了蜡质玉米淀粉、蜡质玉米羟丙基二淀粉磷酸酯、蜡质玉米乙酰化二淀粉磷酸酯添加于番茄沙司后对其加工与储藏稳定性的影响,在加工稳定性方面蜡质玉米羟丙基二淀粉磷酸酯与蜡质玉米乙酰化二淀粉磷酸酯效果相似,均优于蜡质玉米淀粉;储存稳定性方面,蜡质玉米羟丙基二淀粉磷酸酯优于另外2种淀粉,即应用响应面实验筛选出蜡质玉米羟丙基二淀粉磷酸酯为番茄沙司的最佳增稠稳定剂,设计响应面偏差值对比实验,制作出与市售番茄沙司配方接近的实验级番茄沙司,确定了番茄沙司的配方组成。     

不同胶体对玉米淀粉糊化及流变学特性的影响

通过对玉米淀粉中添加不同的胶体(果胶P、黄原胶XG、瓜尔豆胶GG、魔芋胶KGM、阿拉伯树胶AG、羟丙基甲基纤维素HPMC)，并测定其黏度、热力学及流变学特性的变化，探索不同胶体对玉米淀粉糊化及流变学特性的影响。结果表明：不同胶体与玉米淀粉的混合体系容易产生各种反应与相互作用，从而表现出不同的糊化及流变学特性。添加阿拉伯树胶后的混合胶体黏度变化速度降低，而添加其余胶体后混合体系的黏度均升高，添加黄原胶后混合胶体的起始黏度升高，而添加了其他的胶体后变化不大。在25～180℃，DSC结果表明：添加了果胶和黄原胶后的混合胶体起始温度升高，而其他的胶体均下降，且全部的终止温度都有提高。添加了不同胶体与原淀粉的混合体系均随剪切频率增大而出现剪切稀化现象，所以可以确定体系为假塑性流体。添加了果胶、黄原胶的胶体表观黏度小于原淀粉，而添加其他胶体(瓜尔豆胶、魔芋胶、阿拉伯树胶、羟丙基甲基纤维素)的混合体系均有不同程度地升高。玉米淀粉与添加胶体的混合体系的结构发生了一些变化，导致混合体系的特性也发生变化，结果显示添加了胶体(P和AG)后混合体系的硬度比原淀粉升高，添加其他的胶体均减小；添加了胶体(P和KM...     

交联作用对合成交联羟丙基玉米淀粉的影响

以合成的羟丙基玉米淀粉为原料,以三偏磷酸钠为交联剂研究了交联作用对合成交联羟丙基玉米淀粉的影响,并探究了羟丙基玉米淀粉粘度与取代度、交联羟丙基玉米淀粉粘度与交联度之间的关系。结果表明交联剂用量、交联时间、交联温度和交联pH值是影响合成交联羟丙基玉米淀粉的主要因素,羟丙基和交联羟丙基玉米淀粉的最高粘度分别随取代度和交联度的升高而增加;冷却至室温,粘度分别随取代度和交联度的升高而减小。     

油酸和麦芽糖醇混合物对玉米淀粉老化特性的影响

为探究油酸和麦芽糖醇混合物抑制玉米淀粉老化的效果,通过快速黏度分析、差示扫描量热分析、质构分析、动态流变分析、低场核磁共振分析、红外光谱分析和X射线衍射分析等方法比较不同复配比例的油酸和麦芽糖醇混合物对玉米淀粉糊化特性、老化特性、流变学特性、质构及结晶结构等的影响。结果显示：添加油酸和麦芽糖醇混合物后,玉米淀粉的糊化温度升高,回生值和老化速率降低,且当油酸和麦芽糖醇质量比为0.5∶1.5时,糊化温度最高（77.80 ℃）,回生值最低（1 218 cP）,老化速率比原淀粉降低了60%;油酸和麦芽糖醇混合物的添加能增大玉米淀粉的损耗角正切值和横向弛豫时间（T2）,形成较弱的凝胶结构,降低玉米淀粉凝胶的硬度、短程有序度和相对结晶度;当油酸和麦芽糖醇为0.5∶1.5质量比复配时,混合物对延缓玉米淀粉老化存在协同作用。这可能与麦芽糖醇能抑制淀粉体系中水分子运动、油酸能与淀粉形成淀粉-脂质复合物从而有效抑制淀粉重结晶有关。研究结果可为改善玉米淀粉加工特性、提高淀粉基食品品质提供一定的理论依据。     

Performance of lactating dairy cows fed ryegrass silage and corn silage with ground corn, steam-flaked corn, or hominy feed

Forty-eight mid-lactation Holstein cows were used in a 6-wk completely randomized block design trial with a 4 × 3 factorial arrangement of treatments to determine the effects of feeding different proportions of corn silage and ryegrass silage with supplemental ground corn (GC), steam-flaked corn (SFC), and hominy feed (HF) on the performance of lactating dairy cows. Forage provided 49% of the dietary dry matter in the experimental diets, which were formulated to meet National Research Council requirements. Ryegrass silage provided 100, 75, 50, or 25% of the total forage dry matter, with corn silage supplying the remainder. There were no interactions between the proportion of forage provided by ryegrass silage and energy supplement. Dry matter intake and milk protein percentage decreased linearly with increasing proportions of ryegrass silage, but milk protein yield was similar among forage treatments. There were no differences among forage treatments in milk yield, milk fat percentage and yield, and energy-corrected milk yield. Dry matter intake was higher and there was a tendency for increased milk fat percentage for GC compared with SFC or HF. No other differences were observed in milk yield or composition among energy supplements. Plasma urea nitrogen and glucose concentrations were similar among treatments. Under the conditions of this trial, our results indicate that feeding a combination of corn silage and ryegrass silage is more desirable than feeding ryegrass silage alone, whereas supplementation with GC, SFC, or HF supports similar levels of milk production.     

Performance of dairy cows fed annual ryegrass silage and corn silage with steam-flaked or ground corn

Twenty-four lactating Holstein cows were used in a 6-wk randomized block design trial with a 2 × 2 factorial arrangement of treatments to determine the effects of feeding ground corn (GC) or steam-flaked corn (SFC) in diets based on either annual ryegrass silage (RS) or a 50:50 blend of annual ryegrass and corn silages (BLEND). Experimental diets contained 49.6% forage and were fed as a total mixed ration once daily for 4 wk after a 2-wk preliminary period. No interactions were observed among treatments. Cows fed BLEND consumed more dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) than those fed RS, but total-tract digestibility of OM, NDF, and ADF was greater for RS than for BLEND. No differences in nutrient intake were observed among treatments during wk 4 when nutrient digestibility was measured, but digestibility of DM and OM was greater for SFC than for GC. Cows fed BLEND tended to produce more energy-corrected milk than those fed RS, resulting in improved efficiency (kg of milk per kg of DM intake). When diets were supplemented with SFC, cows consumed less DM and produced more milk that tended to have lower milk fat percentage. Yield of milk protein and efficiency was greatest with SFC compared with GC. Blood glucose and milk urea nitrogen concentrations were similar among treatments, but blood urea nitrogen was greater for cows fed GC compared with those fed SFC. Results of this trial indicate that feeding a blend of annual ryegrass and corn silage is more desirable than feeding diets based on RS as the sole forage. Supplementing diets with SFC improved performance and efficiency compared with GC across forage sources.     

高油玉米的综合开发

高油玉米籽粒的含油量高达7%～10%,作为一种新的油料作物,具有广阔的应用前景.对高油玉米与普通玉米的品质进行了对比,高油玉米籽粒不仅含油量高,而且蛋白质、必需氨基酸含量均高于普通玉米.介绍了玉米油的营养价值及提取工艺,玉米油是一种含有大量不饱和脂肪酸及维生素E的营养价值较高的食用植物油,它的传统提取工艺主要有压榨法和浸出法,基于传统工艺存在的问题,可采用新兴的水酶法提取工艺,该工艺设备简单,操作安全,污染少,所得清油品质高,与传统工艺相比有着无可比拟的优越性.高油玉米提取玉米油后,其淀粉可加工生产变性淀粉、酒精、淀粉糖、山梨醇、味精等多种产品,广泛用于食品、医药和化工领域.高油玉米不仅是提取高质量玉米油的原料,它还是一种优质饲料,所以开发高油玉米符合我国玉米结构调整、改进品质、增加效益的大方向,对我国农工贸一体的农业产业化起到重要的推动作用.     

玉米秸皮浆与改性秸穰混合抄纸的研究

烧碱-蒽醌玉米秸皮浆中加入改性玉米秸穰后,除对浆白度和返黄值稍有不利影响外,大大改善了浆的其他性能,尤其表现在浆的强度性能方面。当浆中改性玉米秸穰含量为50%时,抗张指数、耐破指数达到最大值,与原浆相比,分别增加了121.20%和113.40%;耐折度的改善更加明显,耐折次数增加了23倍;撕裂指数的增加呈现先上升后下降的趋势,在改性玉米秸穰含量为30%时,撕裂指数达到最大值,与原浆相比增加了28.87%。     

浑浊型玉米浆玉米须复合饮料的研制

研究浑浊型玉米浆玉米须复合饮料的制备工艺。重点探讨糖、酸等辅料添加量,复合稳定剂配方及均质工艺对产品品质的影响。结果表明,该复合饮料的最佳配方为玉米原浆与玉米须提取液体积比1∶1,蔗糖7%,乳酸0.03%,盐0.10%,琼脂0.02%,黄原胶0.1%,CMC 0.15%,蔗糖酯0.1%;最佳均质工艺为二次均质工艺,处理温度60℃,第一次均质压力20MPa、第二次均质压力25MPa。     

从玉米胚芽中综合提取油和蛋白粉工艺研究

玉米胚芽资源在国内比较丰富,其含油量及蛋白含量较高.目前用传统方法提取玉米胚芽油,为提高产油率,采用高温榨油技术,使胚芽蛋白变性,所产生的大量玉米胚芽饼粕,只能用低价值的动物饲料.本实验采用玉米胚芽低温干燥、低温破碎和预榨、低温萃取脂肪的工艺,目的在于使玉米胚芽提取脂肪过程,能保持玉米胚芽蛋白不变性.因而用低温萃取后的胚芽饼粕,可用常规碱溶、酸沉法提取玉米胚芽蛋白粉.这种胚芽蛋白粉,含有一定量百分比的赖氨酸、蛋氨酸、苏氨酸、色氨酸、缬氨酸、L苯丙氨酸亮氨酸、异亮氨酸8种必需氨基酸,符合国际粮油/卫生组织所规定的优质蛋白标准,接近于母乳和蛋清蛋白的营养价值.此技术能于工业上采用,将会大大提高玉米胚芽加工业的经济效益.     

玉米粉改性对玉米面条质构特性的影响

利用乳酸菌和蛋白酶对玉米粉修饰改性,分析改性后玉米粉的糊化特性和制备成玉米面条的质构特性。结果表明,玉米粉经修饰改性,糊化温度降低,其他的糊化特征值均增加,玉米粉的凝胶特性得到改善,能显著提高玉米面条的弹性和咀嚼性。     

玉米胚芽饮料的研制

通过对玉米胚芽饮料的风味，口感及稳定性等方面的讨论，确定了最佳工艺和配方，研制出具有较高营养保健功效的饮品。     

丙酮萃取法制取玉米蜡

以玉米蜡糊为原料,采用丙酮萃取法制取玉米蜡。通过单因素实验考察萃取时间、萃取温度、料液比、搅拌速率和萃取次数对玉米蜡提取率和纯度的影响。在单因素实验的基础上,以玉米蜡纯度和提取率为考察指标,利用正交实验优化得到最佳工艺条件。结果表明：玉米蜡的最佳制取条件为料液比1∶ 5、萃取温度50 ℃、萃取时间70 min、搅拌速率300 r/min、萃取次数4次;在最佳条件下,玉米蜡提取率为66.71%,纯度为97.23%,磷脂含量为0.18%,白度为59.86%,酸值（KOH）为0.99 mg/g,皂化值（KOH）为124.56 mg/g,水分及挥发物为0.03%,熔程为68.01～81.98 ℃,丙酮残留为14.98 mg/kg。     

NutriDense corn grain and corn silage for dairy cows

Twenty multiparous Holstein cows, 4 of them surgically fitted with ruminal cannulas, were used in a replicated 4 × 4 Latin square to compare the effects of whole-plant silage and grain produced from NutriDense (ND), leafy NutriDense (LND), or a conventional yellow dent (YD) hybrid on ruminal fermentation, total tract nutrient digestibility, and performance of lactating dairy cows. On a DM basis, diets contained 30.6% corn silage and 27.7% corn grain provided from the 3 hybrids according to the following combinations: 1) YD grain and YD silage, 2) YD grain and LND silage, 3) ND grain and YD silage, and 4) ND grain and LND silage. The average concentrations of crude protein, neutral and acid detergent fiber, and ether extract of LND silage and ND grain were higher, but the contents of nonfibrous carbohydrates and starch were lower than those of their YD counterparts. Although DM intake was similar among treatments, feeding ND grain, LND silage, or both reduced the intakes of nonfibrous carbohydrates and starch but increased the intake of ether extract. Apparent digestibility of starch in the total tract was highest for the diet that contained LND silage and YD grain, whereas the amount and percentage of ether extract that were apparently digested in the total tract was increased and tended to be increased, respectively, by the addition of ND grain, LND silage, or both to the diets. Ruminal fermentation parameters were unaffected by treatments except for the concentration of ammonia nitrogen in the ruminal fluid, which tended to be increased by the feeding of ND grain, LND silage, or both. Production of milk, crude and true protein, fat, lactose, and total solids did not differ among diets. Concentration of milk urea nitrogen increased when the ND grain, LND silage, or both were fed to the cows. Results indicate that ND grain and LND silage were similar to the conventional grain and silage for the feeding of lactating dairy cows.