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玉米角质和粉质胚乳淀粉粒粒径、糊化特性及凝胶质构特性的研究 总被引:2,自引:1,他引:2
以莱农14、青农105、连胜15、隆平206和先玉335玉米为材料,人工分离角质和粉质胚乳,通过显微镜观察淀粉粒粒径,采用快速黏度测定仪(RVA)和物性测试仪(TPA)分析糊化特性和质构特性,比较玉米角质和粉质胚乳淀粉粒粒径、糊化特性和质构特性的差异。结果表明,角质胚乳淀粉粒平均粒径显著大于粉质胚乳;角质胚乳的峰值黏度、崩解值和凝胶回复性显著低于粉质胚乳,峰值时间和糊化温度显著高于粉质胚乳,而凝胶的硬度、弹性、凝聚性、胶着性和咀嚼性除了与胚乳质地有关外,也受品种的影响。在玉米实际加工利用时,可以根据需要选择不同类型的胚乳,以实现玉米胚乳的合理有效运用。 相似文献
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大豆秸秆木聚糖碱法提取及酶解工艺研究 总被引:1,自引:0,他引:1
《中国食品添加剂》2016,(5)
大豆秸秆是木聚糖含量较高的一种农业纤维废弃物,采用碱法考察了不同前处理条件(包括预煮温度,氢氧化钠浓度,料液比和浸提时间等)对大豆秸秆中不溶性木聚糖的提取率的影响。正交实验结果表明:当预煮温度80℃,碱液浓度15%,料液比1∶20,浸提时间4 h时,大豆秸杆中不溶性木聚糖的提取率最高,为34.3%。低聚木糖是一种重要的功能性低聚糖,嗜热踝节菌木聚糖酶为低聚木糖水解用酶,通过单因素实验探究了在嗜热踝节菌木聚糖酶的催化作用下,大豆秸秆木聚糖水解的最佳条件,大豆秸秆在此方面研究尚属空白。实验结果显示:底物浓度为1.0%,酶添加量为30 U/m L,温度设定为60℃,水解时间为240 min的条件下低聚木糖的得率最高,为24.2%,在工业上具有较高的应用价值。 相似文献
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目的:利用不同方式提取不同品种小麦麸皮中的阿拉伯木聚糖(arabinoxylan,AX),对提取的AX进行结构表征并比较其抗氧化性。方法:分别利用碱提、超声辅助木聚糖酶提和超声辅助纤维素酶提法从不同品种小麦麸皮(‘百农207’‘百旱207’‘冠麦1号’‘华育198’和‘华育166’)中提取AX,测定其化学组成,对比其分子质量、分子结构、热稳定性及抗氧化性能。结果:3?种提取方式中,碱提法得率较高,且总糖质量分数较高;酶提法则能更大程度地保留多酚,这可能是酶提AX抗氧化性较好的原因,但在一定程度上降低了AX的分子质量,且酶提AX单糖组分比例与碱提AX差异较大,糖苷键连接方式也更复杂;两种酶提法相比,超声辅助木聚糖酶提AX得率和总糖质量分数更高,但超声辅助纤维素酶提AX多酚质量分数更高,且二者单糖比例及糖苷键连接方式也不同;此外,不同品种麸皮AX的分子质量、单糖比例、糖苷键连接方式及比例不同。结论:碱提、超声辅助木聚糖酶提和超声辅助纤维素酶提3种方法从小麦麸皮中提取得到的AX结构及活性存在明显差异,酶提法相对碱提法AX得率和分子质量较低,但多酚含量较高、抗氧化性能较好;超声辅助木聚糖酶提较... 相似文献
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从玉米麸质中提取的水提阿拉伯木聚糖(WEAX),分别使用过氧化物酶(POX)/H2Q体系和漆酶/O2体系为催化剂制备了WEAX凝胶.采用扫描电子显微镜对阿拉伯木聚糖凝胶的结构进行表征,进一步对凝胶的流变性能、热稳定性和溶胀性能进行了研究.发现过氧化物酶/H2O2体系相较于漆酶/O2体系所制备的凝胶,具有更短的凝胶化时间.热稳定性方面,两种凝胶均在大约250℃左右发生分解.同时,由于质子化作用,两种体系的凝胶在盐酸中的溶胀性远小于在水中的溶胀性. 相似文献
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Ordinary corn kernel endosperm is composed of horny and floury portions. Corn varieties having different endosperm were investigated. Their chemical composition was almost identical, but in tissue structure the floury endosperm is soft and the horny endosperm is hard. The starch isolated from floury endosperm is easier to gelatinize, and higher in viscosity, swelling value, and α-amylase digestibility than the starch from horny endosperm. The floury endosperm is superior to the horny endosperm in such baking products as bread and cookies. 相似文献
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Decorticated grains of three sorghum cultivars of intermediate grain hardness were individually dissected to separate the floury and the corneous endosperm fractions. The starch and polymeric components (amylose and amylopectin) of each of the endosperm fractions were isolated and subsequently characterized. Results indicate that there exist major differences in the properties (granule size distribution, gelatinization temperature, iodine binding capacity, and rate of lintnerization) of the starch and starch components from the endosperm fractions. Close relationships between the starch properties and the strength of the alkali gel of the corresponding endosperm fraction were observed. 相似文献
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研究鸡蛋清卵白蛋白的酶解工艺及其结构性质,以水解度为指标,确定最佳酶源为碱性蛋白酶,其水解度为26.55%,显著优于其他蛋白酶(P<0.05)。以碱性蛋白酶酶解鸡蛋清卵白蛋白,采用单因素和五元二次正交旋转试验研究酶解工艺;针对酶解前后卵白蛋白的功能特性进行分析,并采用紫外扫描、傅里叶红外变换光谱、差示扫描量热针对卵白蛋白及其酶解产物进行结构表征。结果发现,碱性蛋白酶酶解鸡蛋清卵白蛋白最佳工艺条件为反应温度52.5 ℃、反应时间5 h、pH 8.25、酶用量5 500 U/g、底物添加量5%,此条件下水解度为27.88%。酶解后产物表面巯基含量降低了3.6 mol/(L·g),溶解度大幅度提高,起泡性降低了18.18%,泡沫稳定性降低了20.24%,乳化活性指数升高了13.56 m2/g,乳化稳定性提高了10.46%。同时,酶解后的卵白蛋白肽链发生了裂解,有序的二级结构被破坏,暴露出更多氨基酸残基,α-螺旋略有减少,β-转角相应增加,亲水基团也相应的增加。 相似文献
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糙米营养全面但口感差,精米口感细腻但营养流失严重,为使大米营养全面和口感细腻,以抛光处理的东北珍珠米为原料,采用α-淀粉酶作用于整粒大米表面,探讨酶解对大米表面结构的影响。研究结果表明:大米质量25.0 g、酶添加量1.4%、酶解温度40 ℃、酶解时间120 min 时,大米淀粉的水解度为4.54%;酶解后的大米表面有明显的疏松孔洞结构,吸水指数提高0.069 倍,硬度减小,延展性增大,晶型无变化,但结晶度降低。热分解的同步热分析试验结果显示,酶解前后大米的降解温度无明显变化,但酶解后大米的焓值增高,表明其淀粉的结晶区更加稳定。对酶解处理的大米进行富硒性能研究,发现在硒添加量3.0 μg,富硒时间30 min,温度为30 ℃,酶解处理的大米富硒量0.26 μg/g。该研究为精制大米负载功能性成分提供新理念,可全面提高大米的附加值,具有非常好的应用前景。 相似文献
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鳙鱼酶解可溶性蛋白营养特性及品质的研究 总被引:3,自引:1,他引:3
本文研究了鳙鱼酶解可溶性蛋白腥苦味祛除效果、相对分子质量分布、功能特性和营养特性.研究结果表明,在鳙鱼酶解可溶性蛋白的生产过程中,采用复合磷酸盐和TBHQ复配具有较好的腥苦味祛除效果,其腥味平均值为2.1,苦味平均值为1.8,分别比对照降低了1.9和2.2;挥发性盐基氮含量为266.7 mg/kg,比对照降低了22.24%.鳙鱼酶解可溶性蛋白在pH 3.0~10.0条件下均具有良好的溶解性(NSI达93%以上);乳化性方面,脱腥脱苦产品的乳化性和乳化稳定性略高;起泡性方面,脱腥脱苦产品的起泡性高于对照.营养评价结果显示,鳙鱼酶解可溶性蛋白具有良好的营养特性,其中必需氨基酸含量为39.67%,且必需氨基酸的比例均非常接近FAO/WHO推荐的成人模式. 相似文献
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Influence of Enzymatic Hydrolysis on Structure and Emulsifying Properties of Sardine (Sardina pilchardus) Protein Hydrolysates 总被引:1,自引:0,他引:1
The influence of enzymatic modification with Alcalase was studied on surface hydrophobicity, molecular weight distribution and emulsifying properties of ten hydrolysates from sardine differing in degree of hydrolysis. Surface hydrophobicity was evaluated fluorometrically using 1 anilino-8-naphthalenesulfonate (ANS); molecular weight distribution was determined by gel chromatography on a Superfine Sephadex G50. Emulsifying capacity and stability were evaluated as functions of pH values and product concentration, in comparison with sodium caseinate. Results showed emulsifying properties, surface hydrophobicity and the high molecular weight fraction decreased as degree of hydrolysis increased. Thus production of hydrolysates with desired molecular structures and emulsifying properties is possible. 相似文献
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Enzymatic Hydrolysis of Casein: Effect of Degree of Hydrolysis on Antigenicity and Physical Properties 总被引:23,自引:0,他引:23
MOHAMED I. MAHMOUD WILLIAM T. MALONE CHRISTOPHER T. CORDLE 《Journal of food science》1992,57(5):1223-1229
Casein was enzymatically hydrolyzed for potential use in a hypoallergenic infant formula. Samples from the digest at different hydrolysis time (HT) intervals were tested for antigenicity, hydrophobicity, net charge (zeta potential), and emulsifying activity. Casein antigenicity loss could be approximated by three-phased first-order kinetics. Extensive antigenicity loss occurred during the first 10% of HT and relatively small changes occurred during the remaining 90% of HT. Hydrophobicity and emulsifying activity decreased, while the magnitude of the net charge increased (P <0.01) with increasing degree of hydrolysis. Strong correlations (r2≥ 0.89) were found among hydrophobicity, emulsifying activity and zeta potential. 相似文献