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《中国奶牛》2015,(1)
通过测定不同温度下市售玉米粉酰胺Ⅲ带的红外光谱(一维红外光谱、二阶导数红外光谱、四阶导数红外光谱和去卷积红外光谱)进一步研究温度对玉米粉蛋白质二级结构的影响。研究发现,玉米粉的一维红外光谱的分辨率不高;玉米粉的二阶导数红外光谱的分辨率优于一维红外光谱,其中1260cm-1处的吸收峰归属于蛋白质无规卷曲结构,1285cm-1处的吸收峰归属于蛋白质β-转角结构;四阶导数红外光谱的分辨率要进一步优于二阶导数红外光谱,其中1225cm-1处的吸收峰归属于蛋白质β-折叠结构,而1315cm-1处的吸收峰归属于蛋白质α-螺旋结构;玉米粉去卷积红外光谱中,随着测定温度的升高,α-螺旋结构、β-转角结构、无规卷曲结构和β-折叠结构的红外吸收强度均有所增加。最后研究了玉米粉酰胺Ⅲ带的二维红外光谱(同步二维红外光谱和异步二维红外光谱)。研究发现,随着测定温度的升高,玉米粉蛋白质二级结构的红外吸收强度变化快慢趋势是:1285cm-1(β-转角结构)1260cm-1(无规卷曲结构)1225cm-1(β-折叠结构)1315cm-1(α-螺旋结构)。结果表明,玉米粉蛋白质的二级结构中,β-转角结构对于温度比较敏感,而α-螺旋结构则相对稳定。采用红外光谱研究玉米粉蛋白质二级结构可行,并为研究玉米粉的热稳定性提供了一个新的研究方法。 相似文献
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为评价酶解与包合技术对破壁与未破壁蜂花粉水溶性蛋白质含量的影响,选用木瓜蛋白酶、菠萝蛋白酶、中性蛋白酶、柚苷酶、碱性蛋白酶、胃蛋白酶以及β-环糊精开展酶解与包合技术制备水溶性蜂花粉的比较试验。结果显示,采用β-环糊精处理破壁蜂花粉,其产物的水溶性蛋白质含量最高(P0.05),而碱性蛋白酶处理未破壁蜂花粉的效果显著高于其他处理(P0.05);添加量、反应温度、时间及p H能够显著影响β-环糊精及碱性蛋白酶包合及酶解蜂花粉的效果,包合技术处理破壁蜂花粉的最佳工艺为环糊精添加量250.0 mg/g,反应温度37℃,反应时间5 h以及p H 8.7,碱性蛋白酶处理未破壁蜂花粉的最佳工艺为酶添加量1500 U/g,反应温度50℃,反应时间4 h以及p H 9.5。综上,该研究认为,β-环糊精及碱性蛋白酶处理能够显著提高蜂花粉的水溶性蛋白质含量,在实际生产中需根据蜂花粉不同的预处理情况选择合适的技术制备水溶性蜂花粉。 相似文献
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为筛选黄粉甲蛹的最佳贮存温度和时间,实现管氏肿腿蜂的规模化生产,将黄粉甲蛹经9℃、3℃、-3℃和-9℃分别贮存5 d、15 d、25 d、35 d和45 d后取出,测定其体内蛋白质、总糖、海藻糖、糖原、还原糖和脂肪含量变化情况。结果表明,经不同时间和低温贮存后,黄粉甲蛹体内的营养物质含量变化差异显著。蛋白质、总糖、海藻糖、糖原和脂肪含量均随贮存时间的延长而降低,其中总糖、海藻糖和糖原含量随着贮存温度的升高而加速消耗,而蛋白质和脂肪在9~-3℃的范围内含量变化同总糖等一致,若达到-9℃后,贮存相同时间的黄粉甲蛹体内其含量明显低于-3℃的。还原糖含量变化同上述各营养物质相反,随贮存温度和时间的增加而显著增加,最高含量可达到未贮存前的4倍之多。 相似文献
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许多研究证明,草粉在贮存过程中其蛋白质、糖、脂肪和胡萝卜素等营养物质的含量均有下降,这些变化在很大程度上受外界环境所影响. 相似文献
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茶(Camellia sinensis)蜂花粉与蜂粮中花粉形态和营养成分的比较 总被引:2,自引:0,他引:2
采用扫描电子显微镜观察茶蜂花粉和不同酿制时间的蜂蜂中花粉粒外部形态和萌发沟,没有发现花粉的细胞壁和细胞结构被破坏的迹象,花粉粒在蜂粮酿制过程中外部形态保持不变。通过体外模拟消化试验和光学显微镜观察,发现蜂粮中花粉粒内含物外吐的数量比蜂花粉多,而且在蜂粮酿制过程中,随着时间的延长,其内含物外吐的花粉粒所占的比例增加,花粉内含物外吐使花粉更易于被破壁和消化。蜂花粉和蜂粮中营养成分测定结果表明,蜂粮配制初期,由于蜜蜂的添加物和乳酸发酵的作用,其蛋白质、总糖含量比蜂花粉高;随着配制时间的延长,蜂粮中营养成分有下降的趋势。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献