泥腌、水腌咸蛋的理化指标和滋味品质差异分析

目的 研究单个泥腌与大缸水腌加工咸蛋品质的差异。方法 在18 ℃恒温下、用25.5% (m/m)的盐水水腌和25%的盐泥泥腌咸蛋, 测定腌制过程中咸蛋含盐率、含水率、游离氨基酸、感官评价等指标, 分析泥腌、水腌咸蛋盐分渗透规律、咸蛋含盐含水与感官品质间相关性、氨基酸味道强度值与滋味品质间的关系。结果 水腌咸蛋25 d成熟, 蛋白含盐率4.99%、蛋黄含盐率1.18%, 蛋内进盐量1.87 g, 盐利用率8.68%; 泥腌蛋35 d成熟, 蛋白含盐率3.53%、蛋黄含盐率1.87%, 蛋内进盐量1.48 g, 盐利用率38.95%。咸蛋的R值(蛋白或蛋黄的含盐含水比)、Q值(蛋黄与蛋白的平衡系数)、N值(蛋白蛋黄含盐比)均与感官品质有显著相关性(P＜0.05)。结论 单个泥腌制作的咸蛋蛋白不咸、蛋黄咸鲜, 品质更好, 其盐分利用率高于水腌方式。咸蛋的R值、Q值、N值可作为评价咸蛋综合感官品质和成熟度的定量指标。     

小麦粉中虫卵的快速检测技术的研究与比较

为了建立一种快速检测小麦粉中昆虫虫卵的方法,比较研究了浮选法、尿酸检测法、几丁质检测法和染色法4种方法检测小麦粉中虫卵的效果及优缺点的比较。结果表明浮选法最高检出率为5.59%,不适用于虫卵检测;几丁质检测法只能证明虫卵中有几丁质,但无法定量;尿酸检测法中检测出的尿酸浓度与虫卵数成正相关,相关系数R2为0.998 6,最低检出限为0.1粒卵/g;利用溴甲酚绿和酸性品红将小麦粉染色的结果是溴甲酚绿将虫卵染成黄橙色,小麦粉染成褐绿色;酸性品红将虫卵和小麦粉都染成紫色,但小麦粉被染颜色更深。染色法虫卵检测率约为75%,初步可以用于小麦粉中虫卵的快速检测。随机取样的小麦粉检测与实际发生虫量比较发现尿酸检测法的检测率为73.3%,染色法的检测率为85%。说明了尿酸法和染色法可以初步用于小麦粉中昆虫虫卵的检测,其灵敏度和操作规范有待进一步优化和研究。     

无损检测技术在禽蛋破损自动检测中的应用

分析了目前国内外利用无损检测技术进行禽蛋破损检测研究的现状及存在的问题，提出了今后研究的方向与发展途径。     

不同品种鲜蛋品质差异分析

目的探究褐壳蛋、粉壳蛋和白壳蛋3种类型鸡蛋的品质差异以及对于蛋粉加工的潜在影响。方法选用京红1号、京粉1号和京白1号所产的褐壳蛋、粉壳蛋和白壳蛋作为试验对象,对37周龄和51周龄蛋鸡所产3种类型鸡蛋的蛋品质进行分析比较。结果 37周龄和51周龄的白壳蛋蛋壳厚度、蛋壳比例和蛋壳强度均显著低于其他2个类型鸡蛋(P0.05);37周龄时3种类型鸡蛋的蛋黄水分含量没有显著性差异(P0.05);白壳蛋蛋清水分含量以及总水分含量均较其他2个类型鸡蛋要低。37周龄时褐壳蛋的蛋黄蛋白质和脂肪含量均显著高于其他2个品种,白壳蛋次之,粉壳蛋最低。37周龄时白壳蛋的蛋清蛋白质含量显著低于其他2个品种。由于蛋清中脂肪含量极少,本试验不予考虑。结论褐壳蛋加工成蛋粉后具有更好的营养价值,而白壳蛋可以提高蛋粉加工的产量。     

鸭蛋黄卵磷脂的提取与精制

以鸭蛋黄为原料,采用乙醇提取法提取鸭蛋中的卵磷脂,设计了四因素正交试验。结果表明,在分离剂(酶)添加量0.05%,乙醇体积分数为90%,提取温度40℃,提取时间60 min条件下,提取粗卵磷脂效果最佳,可制得卵磷脂含量约为80%的粗卵磷脂,得率为10%。进一步用ZnCl2沉淀纯化卵磷脂,对不同浓度ZnCl2进行对比试验,结果表明,40%ZnCl2纯化粗卵磷脂的回收率可达90.8%,薄层层析结果表明只有卵磷脂一个斑点。     

菹草类胡萝卜素的研究——菹草与红心鸭蛋类胡萝卜素特性的初步比较

用菹草喂养蛋鸭能生产优质红心蛋,通过薄层层析及紫外可见吸收光谱等研究,发现菹草含有一类特殊的红色类胡萝卜素,菹草红色类胡萝卜素及部分黄色类胡萝卜素与红心蛋色素有很好的对应关系,证明了红心鸭蛋的红色素来源于菹草;菹草红色类胡萝卜素易溶于丙酮、乙醇、甲醇等极性溶剂,其丙酮溶液的可见吸收光谱峰波长为480nm;菹草和红心鸭蛋中都含有β-胡萝卜素;对菹草类胡萝卜素的部分特性作了初步研究。     

鸡蛋中药物残留的危害与现状

鸡蛋是居民餐桌上重要的食材,鸡蛋的质量和安全是人们关注的焦点。长期食用药物残留超标的鸡蛋,当体内药物蓄积到一定浓度会对人体产生多种急、慢性中毒,严重时会致癌、致畸、致突变,甚至死亡。因此需要健康养殖、合理规范用药,监控和减少药物残留的发生,提高食品安全生物水平工作十分迫切。本文介绍了鸡蛋中药物残留的危害和现状,以期为防范药物滥用或误用造成安全隐患和引导养殖户规范用药提供一定的参考作用。     

Effects of urea analogs on egg hatching and movement of unhatched larvae of monogenean parasiteAcanthocotyle lobianchi from skin ofRaja montagui

Rapid hatching in the monogenean parasiteAcanthocotyle lobianchi from the skin ofRaja montagui is stimulated by urea. Structurally similar to the urea molecule, the following analogs of urea provide amino groups, carboxyl groups, or combinations of these, but fail to stimulate hatching at concentrations of 1 mM in seawater: methylurea (MU); 1, 3-dimethylurea (DU); 1, 1, 3, 3-tetramethylurea (TMU); thiourea (TU); 1, 1, 3, 3-tetramethyl-2-thiourea (TMTU); and 1-phenyl-2-thiourea (PTU). All of these analogs except PTU elicit movements of unhatched larvae, and posttreatment of the eggs with urea showed that the ability to hatch is not impaired by initial treatment with any of the urea analogs. Thus the larval chemoreceptor that initiates hatching appears to be highly specific for the urea molecule.     

Distribution of Botia superciliaris (Günther, 1892) ichthyoplankton in the upper mainstem of the Yangtze River preimpoundment and postimpoundment of the upstream dam cascade

Dam cascades have been a major threat to fishes of the upper Yangtze River. The remaining lotic river segment of the upper mainstem between the Xiangjiaba Dam (XJD) and the Three Gorges Reservoir (TGR) may serve as a critical refuge for endemic fishes. We investigated distribution of ichthyoplankton Botia superciliaris, an endemic species, at three sections preimpoundment and postimpoundment of the XJD, that is, Yibin (close to the XJD), Zhuyang (in the middle of the segment), and Mudong (in the tail of the TGR). Preimpoundment of the XJD, larvae occurred in all three sections, and their abundance tended to be highest at Yibin and lowest at Mudong. Postimpoundment, larval abundance dramatically decreased in all three sections. In particular, no larvae were found at Yibin, and larval abundance tended to be higher at Zhuyang than at Mudong. Eggs were collected from all three sections, and those from Zhuyang accounted for over 90% of the total. Initiation of egg occurrence at Yibin was approximately 1 month later than at Zhuyang and Mudong. Water temperature was lower, and water transparency was higher at Yibin than at Zhuyang and Mudong postimpoundment. We suggest that the decrease in abundance and delayed presence of ichthyoplankton at Yibin postimpoundment of the XJD reflected the impact of upstream dam discharge and that the lower abundance of ichthyoplankton at Mudong compared with Zhuyang both preimpoundment and postimpoundment of the XJD reflected the influence of inundation by the TGR. We recommend that the river sections around Zhuyang become high‐priority conservation areas     

新城疫病毒Lasota系疫苗生产中鸡胚孵化条件的优化

目的优化新城疫病毒Lasota系疫苗生产中鸡胚孵化条件。方法利用正交实验,对影响疫苗效价的鸡胚孵化温度、孵化湿度、照蛋时间间隔等3个因素进行优化。结果鸡胚最佳孵化条件为孵化温度36℃,孵化湿度55%,照蛋时间间隔2h。孵化湿度对疫苗效价有极显著影响,孵化温度和照蛋时间间隔有显著影响。应用优化的条件生产的疫苗,效价为10~(9.5)EID_(50)/0.1ml,明显高于原条件生产疫苗的平均效价10~(8.5)EID_(50)/0.1ml。结论采用优化的生产条件,可明显提高疫苗的效价。