不同干燥方式对梨干质构特性和微观结构的影响

研究了热风干燥和真空冷冻干燥2种干燥方式对梨干质构特性和微观结构的影响。结果表明:2种方式干燥后梨干的内聚性和回复性均显著上升(P0.05),其中热风干燥上升的幅度较大,但是2种方式干燥后的弹性都显著下降(P0.05);与鲜样相比,热风干燥后硬度与咀嚼性均显著增加(P0.05),而真空冷冻干燥后咀嚼性无显著差异(P0.05),硬度显著下降(P0.05);不同热风干燥温度(60、70、80℃)对梨干的质构特性影响差异不显著(P0.05);热风干燥后的梨干微观结构变化较明显,真空冷冻干燥后的细胞组织变得疏松多孔,形变较小。     

不同鸡种及不同产蛋周龄鸡蛋营养成分比较分析

目的比较不同鸡种及不同产蛋阶段所产鸡蛋营养成分的差异。方法在相同条件下饲养海兰褐鸡、苏禽青壳鸡、仿土蛋鸡,比较产蛋前期(21周)、中期(43周)、后期(67周)所产鸡蛋的营养成分及矿物元素含量。结果不同鸡种所产鸡蛋的粗蛋白含量差异不显著(P0.05);海兰褐鸡蛋的干物质、粗脂肪、胆固醇、磷脂、磷、铁、硒等含量均显著小于仿土蛋鸡蛋和苏禽青壳蛋(P0.05),仿土蛋鸡蛋和苏禽青壳蛋二者间差异不显著(P0.05)。产蛋前期鸡蛋的干物质含量显著低于产蛋中、后期(P0.05);仿土蛋鸡和苏禽青壳产蛋前期鸡蛋的粗脂肪含量显著低于产蛋中、后期(P0.05);产蛋前期鸡蛋的胆固醇和磷脂含量显著高于产蛋后期(P0.05),产蛋后期显著高于产蛋中期(P0.05),不同产蛋阶段鸡蛋的粗蛋白、磷、铁、铜和硒含量差异匀不显著(P0.05);不同鸡种在不同产蛋阶段所产鸡蛋的钙、镁、锌、锰等含量存在一定差异。结论青壳蛋和仿土鸡蛋营养成分要优于海兰褐鸡蛋,初产蛋除了磷脂含量较高,其他营养成分基本相同。     

不同饲养方式对各产蛋阶段鸡蛋品质的影响

目的:比较不同饲养方式对鸡蛋品质的影响,为蛋鸡产业化生产提供指导。方法:以如皋黄鸡为试验素材,采用笼养和平养两种饲养方式,测定不同产蛋阶段常规蛋品质、营养成分和矿物元素含量。结果:产蛋初期,平养条件下蛋黄色泽、脂肪和胆固醇含量极显著高于笼养(P0.01),铜和铁含量显著低于笼养(P0.05)。产蛋中期,平养条件下蛋壳强度、蛋黄重量、蛋黄比率、蛋黄蛋白比均显著低于笼养(P0.05);哈氏单位以及蛋白质、维生素E和氨基酸含量均显著高于笼养(P0.05);蛋黄色泽、维生素A和胆固醇含量均极显著高于笼养(P0.01),锰含量极显著低于笼养(P0.01)。产蛋后期,平养条件下胆固醇含量极显著高于笼养(P0.01);蛋白质、维生素A和铜含量显著高于笼养(P0.05);锰含量极显著低于笼养(P0.01);硒含量显著低于笼养(P0.05)。结论:不同产蛋阶段,饲养方式对鸡蛋品质均有一定的影响。     

糙米发芽前后营养成分的变化及其对发芽糙米糊化特性的影响

选用24个糙米品种为原料制备发芽糙米,研究发芽过程中主要营养成分的变化,以及营养成分变化对发芽糙米糊化特性的影响。结果表明,糙米发芽后,总淀粉含量极显著下降(P0.01),可溶性蛋白、纤维素和γ-氨基丁酸的含量极显著上升(P0.01),直链淀粉、总蛋白和粗脂肪含量变化不显著(P0.05)。发芽糙米峰值黏度、最低黏度、最终黏度和回生值与直链淀粉含量呈极显著的正相关(P0.01),与支链淀粉含量、支链淀粉/直链淀粉呈极显著的负相关(P0.01);峰值时间也与直链淀粉含量呈极显著的正相关(P0.01),与支链淀粉、支链淀粉/直链淀粉呈显著负相关(P0.05)。此外,发芽糙米峰值黏度与总蛋白含量呈极显著的负相关(P0.01),最低黏度、最终黏度和回生值也与总蛋白的含量呈显著负相关(P0.05)。     

市售软包装卤蛋产品品质特性分析

对10种市售卤蛋产品进行理化及定量描述性分析,消费者接受性测试,并利用相关性分析方法分析了各指标之间的相互关系。结果表明:10种卤蛋产品各指品质标均存在不同程度的差异,其中黄度b*、蛋黄咀嚼性和甜味3个指标的差异最大,变异系数均在50%以上;p H值、含水率、蛋白含量、TBA值、蛋白蛋黄弹性的差异较小,变异系数均在15%以下。各指标之间存在不同程度的相关性,其中蛋白含水率与蛋白含量、蛋白硬度、蛋白咀嚼性、五香味、甜味呈显著负相关(P0.05),色泽指标L*、a*、b*之间均呈极显著正相关(P0.01),且都与酱香味呈极显著负相关(P0.01)。消费者对各种卤蛋的总体、可按受性外观、气味、滋味和质地喜欢程度也存在显著性差异,10种卤蛋产品的消费者总体可接受度从高到低为84351629710。与消费者总接受性的相关性分析表明,含水率、蛋白含量、质构数值、风味指标与消费者总体可接受性具有显著相关性(P0.05),为影响产品总体可接受性的关键指标。     

褐壳与绿壳鸡胚蛋特色营养物质的含量变化

根据比色法原理,采用酶标仪对2 个品种鸡胚蛋中的胆固醇、卵磷脂、VE含量进行测定。与0胚龄相比,胆固醇呈明显下降趋势,5～12胚龄降幅最大,12胚龄后保持稳定;卵磷脂含量无显著性变化;VE含量逐渐增加,到12胚龄均增加了4 倍,之后保持稳定。2 个品种相比,入孵前绿壳蛋中胆固醇含量为褐壳蛋的79.37%,极显著低于褐壳蛋（P＜0.01）;孵化至12胚龄后,2 个品种的胆固醇含量差异不显著（P＞0.05）;绿壳蛋中的VE无论是在入孵前还是在孵化后期均极显著高于褐壳蛋（P＜0.01）;绿壳鸡胚蛋中的卵磷脂含量与褐壳蛋相比差异不显著（P＞0.05）。总体看来,随着孵化日龄的增加,2 个品种鸡胚蛋中的同种营养成分的变化趋势一致;在12胚龄后胆固醇大大降低,VE含量显著增加,且卵磷脂含量丰富,具有更高的食用价值。     

低温脱脂大豆粕理化性质与挤压组织化特性关系研究

以2012年9家大豆蛋白生产企业的9份低温脱脂大豆粕为原料,以同向啮合双螺杆挤压机为挤压设备,采用相关性和主成分法分析大豆粕理化性质与挤压组织化系统参数、产品特性的关系。结果显示,挤压机扭矩与挤压组织化蛋白的硬度、咀嚼度、拉断强度呈极显著正相关(P0.01);模头处物料的表观黏度与挤压组织化蛋白硬度呈极显著正相关(P0.01),与挤压组织化蛋白咀嚼度、拉伸强度呈显著正相关(P0.05);单位机械能耗与色差ΔE*、咀嚼度、拉断强度之间呈显著正相关(P0.05);大豆粕粗蛋白含量和挤压组织化产品硬度、咀嚼度、拉断强度之间正相关系数大于0.543;乳化性与挤压组织化蛋白组织化度的正相关系数为0.627。主成分载荷分布和得分分布图显示,参试大豆粕中P_1、P_2和P_7的粗蛋白含量及其产品硬度较高;P_3和P_9的乳化性及其产品组织化度较高;P_5和P_7的粗纤维含量较高。结论认为,粗蛋白含量较高的大豆粕可生产出拉断强度较大、硬度和咀嚼度较高的挤压组织化蛋白;粗蛋白含量、乳化性可作为挤压组织化蛋白生产原料大豆粕的分类性状。     

低温脱脂大豆粕理化性质及挤压组织化特性关系研究

以2012年9家大豆蛋白生产企业的9份低温脱脂大豆粕为原料,以德国Brabender DSE-25型同向啮合双螺杆挤压机为挤压设备,采用相关性和主成分法分析大豆粕理化性质与挤压组织化系统参数、产品特性的关系。结果显示,挤压机扭矩与挤压组织化蛋白的硬度、咀嚼度、拉断强度呈极显著正相关(P<0.01);模头处物料的表观黏度与挤压组织化蛋白硬度呈极显著正相关(P<0.01),与挤压组织化蛋白咀嚼度、拉伸强度呈显著正相关(P<0.05);单位机械能耗与色差△E*、咀嚼度、拉断强度之间呈显著正相关(P<0.05);大豆粕粗蛋白含量和挤压组织化产品硬度、咀嚼度、拉断强度之间正相关系数大于0.543;乳化性与挤压组织化蛋白组织化度的正相关系数为0.627。主成分载荷分布和得分分布图显示,参试大豆粕中P1、P2和P7的粗蛋白含量及其产品硬度较高;P3和P9的乳化性及其产品组织化度较高;P5和P7的粗纤维含量较高。结论认为,粗蛋白含量较高的大豆粕可生产出拉断强度较大、硬度和咀嚼度较高的挤压组织化蛋白;粗蛋白含量、乳化性可作为挤压组织化蛋白生产原料大豆粕的分类性状。     

宁都黄鸡蛋与常见市售鸡蛋品质比较分析

测定并比较了宁都黄鸡蛋(36枚)、白壳蛋(15枚)、褐壳蛋(23枚)和土鸡蛋(14枚)的蛋重、哈氏单位等10项蛋品质指标。结果表明:宁都黄鸡蛋与其他3种鸡蛋的蛋品质存在着差异,其中蛋形指数、蛋壳比率差异不显著(P0.05);在蛋重方面,除与土鸡蛋差异不显著外,与白壳蛋、褐壳蛋差异极显著(P0.01);在蛋的密度方面,与白壳蛋、褐壳蛋差异不显著(P0.05),与土鸡蛋差异显著(P0.05);在蛋壳厚度方面,与其他3种鸡蛋均差异极显著(P0.01);在蛋壳质量方面,与白壳蛋、褐壳蛋差异极显著(P0.01),与土鸡蛋差异显著(P0.05);在浓蛋白高度、哈氏单位、蛋黄比率、蛋白比率方面,与白壳蛋差异不显著(P0.05),与褐壳蛋、土鸡蛋差异极显著(P0.01)。     

天然食用胶替代部分脂肪对西式香肠品质特性的影响

以不添加任何天然食用胶为对照,分别添加海藻酸钠和亚麻籽胶制备脂肪含量低于5%的低脂香肠,通过测定其蒸煮损失率、保水性、颜色、感官评定、质构特性以及微观结构,研究天然食用胶对西式香肠品质的影响。结果表明:相对于对照组,海藻酸钠替代组和亚麻籽胶替代组的颜色和风味无显著性差异(P>0.05),而蒸煮损失显著减少(P <0.05),保水性显著增加(P <0.05)。感官评定、质构测定和扫描电镜结果表明,海藻酸钠替代组和亚麻籽胶替代组的硬度、弹性、咀嚼性和总体接受性均显著性提高(P <0.05)。天然食用胶是多糖类大分子物质中较为理想的脂肪替代物。     

日粮中添加不同油脂对鸡蛋工艺特性及质构指标的影响

摘 要：目的 本试验旨在探究蛋鸡饲粮添加不同油脂后对鸡蛋起泡性、乳化性、凝胶特性及蛋黄TPA、剪切力及蛋黄膜强度的影响。方法 在玉米-豆粕型基础日粮的基础上,分别添加1.5％豆油、1.5％猪油、1.5％混合油脂。结果 试验结果表明：与对照组相比,添加1.5％的猪油和混合油脂会不同程度的降低鸡蛋的工艺特性,显著增加蛋黄的硬度、咀嚼性;而1.5％豆油对鸡蛋的工艺特性及质构指标不会造成不良影响。结论 因此,为了满足蛋鸡生长能量需求及蛋品功能特性,建议在日粮中添加1.5％豆油。     

贮藏温度-时间变化对壳蛋新鲜度影响研究

该文以新鲜罗曼粉壳蛋为研究对象,研究5个贮藏温度-时间变化组壳蛋新鲜度指标变化,分别于0、10、20、30 d检测所有实验组壳蛋失重率、气室高度、哈夫单位、蛋黄指数、浓稀蛋白比、蛋清pH。结果表明,贮藏期间壳蛋失重率、气室高度和蛋清pH显著升高（P<0.05）,哈夫单位、蛋黄指数和浓稀蛋白比显著下降（P<0.05）。贮藏20 d时,处理组5壳蛋哈夫单位和蛋黄指数显著高于（P<0.05）对照组1、处理组1、处理组2和处理组3,而失重率、气室高度、蛋清pH较低（P<0.05）。贮藏30 d时,处理组5壳蛋失重率和气室高度显著低于对照组1、处理组1和处理组3（P<0.05）,蛋黄指数显著高于对照组1、处理组2、处理组3、处理组4（P<0.05）。除失重率、哈夫单位外,对照组2与处理组5壳蛋新鲜度指标整体差别不大。因此,除了壳蛋自身品质外,需要尽可能延长低温（4 ℃）贮藏时间,延缓壳蛋新鲜度指标劣变。     

EFFECT OF HEN EGG PRODUCTION AND PROTEIN COMPOSITION ON TEXTURAL PROPERTIES OF EGG ALBUMEN GELS

The effect of hen age, strain and dietary amino acid intake on the egg albumen gel textural properties was studied in two experiments by textural profile analysis (TPA) and uniaxial compression (UC) tests. In experiment 1, eggs from 4 different hen flocks were heat processed industrially. Egg rejection due to poor albumen gelling was correlated to hen age (r = 0.502), albumen dry matter (r =−0.632), gel hardness of 1^st compression (r =−0.765), and gel work of 1^st compression (r =−0.740) in TPA. In experiment 2 two hen strains, representing two levels of egg production, were fed diets with supplementation of L-lysine, methionine or both amino acids compared to a control diet. The lysine intake ranged from 818–1272 mg/hen/day and methionine intake from 377–575 mg/hen/day among hen groups, but without significant effect on the albumen gel texture parameters. The hen strains differed significantly in egg production (P<0.001), physical (P<0.001), chemical (P<0.05) and gel textural parameters of egg albumen (P<0.01). Hen age was essential, and correlated to the industrial egg rejection (r = 0.729), albumen dry matter (r =−0.902) and gel stress at fracture (r =−0.884). Albumen gels with high fracture stress values were found to contain a modified form of ovofransferrin.     

贮藏温度变化对壳蛋新鲜度的影响

该文以新鲜罗曼粉壳蛋为研究对象,研究4个贮藏温度变化处理组壳蛋新鲜度指标的变化,分别于0、10、20、30 d检测所有实验组壳蛋失重率、气室高度、哈夫单位、蛋黄指数、浓稀蛋白比和蛋清pH。结果表明,贮藏10～30 d,处理组2、处理组3、处理组4的失重率显著升高(P<0.05),而气室高度和浓稀蛋白比显著降低(P<0.05),除对照组外,所有处理组壳蛋pH呈现先升高后下降的趋势,处理组3和处理组4的蛋黄指数下降趋势更为明显。对照组和处理组1壳蛋的哈夫单位、蛋黄指数和浓稀蛋白比显著高于(P<0.05)处理组3和处理组4。在贮藏10～20 d时,处理组2的壳蛋pH显著高于(P<0.05)对照组和处理组1。因此,如果前10 d常温贮藏温度≥20℃时,引起壳蛋失重率的增加和哈夫单位的下降,与低温(4℃)贮藏相比,采用贮藏温度变化(常温-低温)贮藏壳蛋更容易引起壳蛋新鲜度指标的下降。     

Growth of Salmonella enteritidis in artificially contaminated eggs: the effects of inoculum size and suspending media.

Growth profiles of two isolates of Salmonella enteritidis phage type (PT) 4 inoculated into either the albumen of whole shell eggs or into separated albumen were found to be markedly affected by the size of the inoculum and the composition of the medium used to suspend the cells prior to inoculation. Using our model with an inoculum of two cells, multiplication of the Salmonella was not seen in 93% of eggs held at 20 degrees C for 8 days. In approximately 7% of eggs, however, growth occurred during the 8 days of storage. If the inoculum equaled or exceeded 25 cells per egg when eggs were subsequently stored at 20 degrees C, or 250 cells per egg when eggs were stored at 30 degrees C, high levels of growth of Salmonella in the egg occurred significantly more frequently than when the inoculum was two cells. High levels of growth were also seen more frequently if the inoculum was suspended in buffered peptone water or maximal recovery diluent rather than in phosphate buffered saline. Growth of Salmonella in separated albumen occurred very infrequently (1.1% of samples) at low inoculum levels and did not become significant until the inoculum was 250 cells or greater. Growth in the albumen was unaffected by the composition of the suspending medium. Provided that the inoculum was approximately 2 cells per egg and the bacteria were suspended in PBS, observed growth profiles of S. enteritidis inoculated into the albumen of whole eggs resembled those in naturally contaminated eggs.     

基于低场核磁共振技术分析不同贮藏条件下白煮蛋水分分布及品质变化

研究去壳及带壳白煮蛋在冷藏（4 ℃）和室温（25 ℃）贮藏过程中水分体积分数、氧化情况、质构及颜色 等品质的变化,采用低场核磁共振、质构分析及扫描电子显微镜等技术分析样品的水分分布、质构特性和微观结 构,通过测定羰基含量及硫代巴比妥酸反应产物含量反映蛋白质和脂肪氧化情况。结果表明：在贮藏过程中,白煮 蛋蛋清和蛋黄的水分体积分数,尤其是不易流动水体积分数,随着贮藏时间的延长而减少（P＜0.05）,蛋白及脂 肪氧化程度逐渐增加,去壳处理是这些变化的重要影响因素;同时,白煮蛋硬度和咀嚼性随贮藏时间的延长逐渐 增加,凝胶微观结构更加致密,感官品质下降,但在所有实验组中,4 ℃带壳贮藏的白煮蛋品质变化幅度最小;贮 藏温度对白煮蛋颜色无显著影响（P＞0.05）,但去壳处理使得白煮蛋颜色发生显著变化（P＜0.05）。综合分析表 明,白煮蛋在贮藏中水分的损失和氧化是导致其品质下降的重要原因,带壳冷藏是白煮蛋较好的贮藏条件。     

Laying season and egg shell cracks on the growth of Salmonella enteritidis in the egg albumen during storage

We studied the effects of laying seasons and egg shell cracks on the ability of egg albumen to support the growth of Salmonella Enteritidis (SE) in eggs. Hens eggs used were those laid in February, June, and October in a farm in Japan and stored at 10, 20, and 30 degrees C, and at 30 degrees C after storage at 10 degrees C, immediately after receipt or after cracking the shell. At several-day intervals during storage, the egg contents were poured into a dish, SE was inoculated into albumen, and then the growth of SE during 3 days incubation at 18 degrees C was measured. The results demonstrated that storage temperature and laying season affected the growth of SE in the egg albumen. The proportion of eggs upon which albumen allowed the growth of SE was higher in the eggs stored at 30 degrees C than those stored at 10 degrees C. The growth of SE in eggs was lowest in the following order of laying: February, October, and June. SE grew preferably in albumen of cracked eggs than intact eggs.     

不同煮制时间对水煮鸡蛋质构及蛋黄脂质成分的影响

将新鲜鸡蛋分别在沸水中煮制10、15、20、25 min,通过测定蛋清水分含量、蛋黄水分含量、水分T₂驰豫分布、质构以及蛋黄脂质组成,探究不同煮制时间对鸡蛋质构及脂质营养成分的影响。结果表明,蛋清蛋白在煮制15 min后完全凝胶,而蛋黄则在20 min后完全凝胶。蛋黄中具有生物活性功能的磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、磷脂酰己醇(PI)、磷脂酸(PA)、磷脂酰甘油(PG)和神经酰胺(Cer)均在煮制15 min的样品中含量最高,只有鞘磷脂(SM)的含量在煮制时间10 min的样品中含量最高,其次是煮制15 min的样品。单不饱和脂肪酸(∑MUFA)含量煮制前15 min下降显著(p<0.05),之后延长煮制时间变化不显著(p>0.05);而多不饱和脂肪酸(∑PUFA)则在煮制前15 min含量变化不显著,之后随煮制时间延长含量显著下降(p<0.05)。由此可得,煮制时间为15 min时,鸡蛋的质构及蛋黄脂质营养最好,这将为工业化生产早餐水煮鸡蛋或者卤蛋生产提供一定的理论指导。     

Development of nutraceutical egg products with omega-3-rich oils

Novel, nutritionally-enhanced egg products were developed by substituting saturated fat and cholesterol-containing yolk with omega-3 fatty acids-rich (ω-3 FA) flaxseed, menhaden, algae, and krill oils. The ω-3 FA-fortified eggs are typically developed through alteration of hen feed. However, the present study aimed at creating such a product via processing. Experimental egg products were developed to match composition, color, and texture of hen eggs (mixed whole egg). Experimental egg products, mixed whole egg, and liquid egg product (Egg Beaters™) were cooked, analyzed, and compared. Moisture, protein, and fat content of experimental egg products matched (P > 0.05) whole egg. The L^∗ (lightness) for experimental egg products was generally similar to mixed whole egg except when krill oil was added. Experimental egg products had higher (P < 0.05) a^∗ and b^∗ than mixed whole egg and Egg Beaters™, indicating more redness and yellowness, respectively. Texture profile analysis (TPA) values (hardness, springiness, cohesiveness, gumminess, chewiness, and resilience) revealed that experimental egg products had similar (P > 0.05) and greater (P < 0.05) textural properties when compared to mixed whole egg and Egg Beaters™, respectively. Fundamental torsion test confirmed that experimental egg products and mixed whole egg had generally similar texture, but were firmer (P < 0.05) than Egg Beaters™. Kramer shear test indicated a trend (P > 0.05) of slightly firmer texture for experimental egg products than Egg Beaters™.     

Outgrowth of Salmonellae and the physical property of albumen and vitelline membrane as influenced by egg storage conditions

This study was undertaken to determine the influence of storage time and temperature on the volume, weight, and pH of egg albumen, the physical strength of vitelline membrane, and the fate of Salmonella Enteritidis artificially inoculated into egg albumen. A fiber-optic probe was used for inoculation with Salmonella Enteritidis at 10(2), 10(4), or 10(6) cells per egg. Both fresh and inoculated eggs were stored at 4, 10, and 22 degrees C for 6 weeks. Five fresh uninoculated eggs from each storage group were collected each week, and the weight, volume, and pH of the egg albumen were measured. The forces, energies, and degrees of membrane deformation required to rupture the vitelline membranes also were determined from either albumen-free yolks or yolks surrounded by albumen. In separate experiments, five inoculated eggs were evaluated each week for populations of Salmonella Enteritidis. When the eggs were stored at 4 degrees C, the albumen retained significantly more volume and weight and had a relatively lower pH. The vitelline membranes from eggs stored at 4 and 10 degrees C required more force and energy for rupture. Salmonellae flourished at 22 degrees C, even in the albumen with the lowest initial population, 10(2) cells per egg. Storage at 4 and 10 degrees C inhibited the growth of salmonellae in the albumen of eggs with initial populations of 10(2), 10(4), or 10(6) cells per egg. In eggs with initial Salmonella populations of 10(6) cells per egg that were stored at 22 degrees C, the populations of reached as high as 10(10) cells per egg after 4 weeks of storage. Storage at 4 and perhaps 10 degrees C postponed the aging process of chicken eggs, preserved the antimicrobial agents of the albumen, and maintained the integrity of vitelline membrane. Low-temperature storage therefore had a significant impact on the safety and overall quality of the eggs.