环境因子对南瓜粉中胡萝卜素影响的研究

依据南瓜粉贮藏过程中胡萝卜素降解的规律,研究了温度、充气包装及光线对胡萝卜素保存率的影响,结果表明,南瓜粉在低于0℃、充N2包装、置暗室中贮藏时,胡萝卜素的保存率最高。     

关于鸡蛋食用价值的探讨

文中主要介绍了鸡蛋的营养价值,从营养成分、蛋黄颜色、风味、药物残留方面比较了散养鸡蛋与笼养鸡蛋的食用价值,功能性鸡蛋的选择食用以及加工储藏对鸡蛋营养物质的影响进行了探讨.为消费者正确认识和食用鸡蛋提供科学依据.     

不同保鲜剂对鸡蛋保鲜效果的研究

对聚乙烯醇、聚乙烯醇和双乙酸钠复合、聚乙烯醇和氢氧化钙复合三种保鲜剂对鸡蛋的保鲜效果进行了比较研究.结果表明:经过30d贮藏,聚乙烯醇和氢氧化钙复合保鲜剂处理的鸡蛋鲜蛋率仍为100%、失重率为2.24%、蛋黄指数为0.39、哈夫单位为73.57、蛋白pH为8.40,蛋黄颜色(L*)值为58.90、(a*)值为7.19、(b*)为39.97.说明聚乙烯醇和氢氧化钙复合保鲜剂保鲜效果最好,明显优于对照组和其他处理组.     

n-3脂肪酸鸡蛋营养价值分析

n-3类脂肪酸健康功效明确,其中EPA和DHA对降低心血管疾病风险等方面有较强作用,但人群摄入量往往不足.研究表明,通过对母鸡饲料进行n-3脂肪酸强化能有效地增加蛋黄内EPA和DHA的含量,其中DHA强化鸡蛋比未强化鸡蛋含量高2.4～10倍.每人每天食用1～2个n-3脂肪酸鸡蛋可使得机体每日摄入的EPA和DHA达到膳食推荐量.而由于n-3脂肪酸的引入,相应的安全性评估也应加强,包括需从n-3脂肪酸的摄入量、n-3脂肪酸鸡蛋里的深海鱼污染物和胆固醇含量等几个方面进行评价.     

不同干燥条件对鸡蛋涂膜保鲜效果的影响

采用5%聚乙烯醇保鲜液在新鲜鸡蛋表面形成保护膜,研究不同干燥方式、干燥时间、干燥温度对鸡蛋哈夫值、蛋黄指数、蛋重变化、pH值的影响,在此基础上,以鸡蛋哈夫值作为指标,设计正交试验研究鸡蛋涂膜后的保鲜效果.结果表明：采用真空条件下,干燥温度55 ℃,干燥时间30 min,鸡蛋保鲜效果最佳.     

不同处理对绿壳鸡蛋保鲜效果的研究

采用三种不同的处理方法对绿壳鸡蛋进行保鲜效果的研究,测定了鸡蛋的外部品质和内部品质的变化。结果表明,涂膜组效果最好,其次为热处理组。哈夫单位(H.U)和蛋黄指数与蛋的新鲜度呈显著的正相关;挥发性盐基氮(TVBN)含量与新鲜度呈显著的负相关。第21d开始,三个处理组间的哈夫单位和蛋黄指数有显著的差异(P<0.05);第28d时,对照组、热处理组和涂膜组挥发性盐基氮含量分别为9.095、8.270和7.560mg/100g,差异显著(P<0.05)。蛋壳厚度、蛋壳强度、蛋黄颜色、气室直径和胆固醇含量在各处理组间没有显著的差异(P<0.05)。      

Effect of beet and honey on quality improvement and carotene retention in a carrot fortified milk product

The effect of beet and honey on quality attributes and carotene retention of carrot fortified milk product during storage at 30 °C were studied. Six types of samples were prepared and stored in a close container at 30 °C for 10 days. The samples were CC [chhana (a heat and acid coagulated milk protein mass i.e. casein mass, analogous to cottage cheese):carrot = 1:1], CCB1 (chhana:carrot:beet = 2:1:1), CCB2 (chhana:carrot:beet = 4:3:1), CCH1 (chhana:carrot:honey = 2:1:1), CCH2 (chhana:carrot:honey = 4:3:1) and CCBH (chhana:carrot:beet:honey = 3:1:1:1). Effect of beet and honey on the quality of the samples was evaluated on the basis of changes in acidity, pH, free fatty acid level and sensory analysis of the samples. Carotene retention was determined on the basis of amount of carotene degraded after processing and storage. With the longer storage time, acidity, free fatty acid content increased and pH, carotene retention as well as colour preferences and overall acceptance decreased for all the samples. Addition of beet and honey in both proportion to the product showed synergistic role i.e. they reduced the acidity and free fatty acid formation, pH reduction and carotene degradation. However, regarding sensory evaluation, honey addition to the carrot based milk product showed better result. Equal mixture of carrot, beet and honey was best regarding antioxidant activity and retention of carotene. The study showed in overall that addition of equal mixture of beet and honey along with carrot is effective for quality improvement and carotene retention of carrot fortified milk product.Industrial relevanceThis study is of relevance because it deals with the effectiveness of natural antioxidant sources (beet and honey) in quality improvement and carotene retention of carrot fortified milk product. Fortification of carrot in milk products at higher concentration (1:1) is a new idea. In addition to that, fortification of beet and honey in carrot fortified milk product for quality improvement and carotene retention is an innovative work. The data represented in the work suggest that addition of 1:1 mixture of beet and honey along with carrot is effective for quality improvement and carotene retention of carrot fortified milk product. The use of natural antioxidant sources particularly in food is always recommended as safe and good medicines for health as well as several diseases. This innovative idea confers benefits in the dairy industry as well as in the agriculture industry by building a bridge between these two industries. Besides, this technology can reduce the spoilage of agricultural commodities due to seasonal glut.     

Effect of various refrigeration temperatures on quality of shell eggs

BACKGROUND: The objective of this study was to evaluate the effects of low storage temperatures on shell egg quality. RESULTS: Approximately 2100 shell eggs were collected and stored at ? 1.1, 0.6, 2.2, 3.9, 5.6 and 7.2 °C for up to 4 weeks. Eighteen eggs at each storage temperature were evaluated after 0, 2, 7, 14, 21 and 28 days of storage. Haugh units (HU), yolk index (YI), albumen pH (pHA), yolk pH (pHY) and angel food cake density (CD) were measured. Shell egg quality tended to be preserved better at below 2.2 °C, as high HU and YI values relative to eggs stored at 7.2 °C were determined on day 28. However, storage at ? 1.1 °C tended to cause the opposite effect, especially highly declined HU values over time. Significantly different HU values of shell eggs were measured after 14 days of storage, with eggs stored at 0.6 and 2.2 °C having the highest HU values, 80.42 and 77.97 respectively. CONCLUSION: A lower temperature limit for shell egg storage could be established between 0.6 and 2.2 °C, as both temperatures showed the highest HU values, 77.88 and 77.60 respectively, after 28 days of storage. Copyright © 2011 Society of Chemical Industry     

Monitoring of layer feed and eggs for Salmonella in eastern Japan between 1993 and 1998

In order to investigate contamination of chicken farms with Salmonella, feed and eggs were sampled from 16 commercial layer farms in eastern Japan between 1993 and 1998 and cultured for salmonellae. Salmonella enterica subsp. enterica isolates belonging to 19 serovars were obtained from the feed. Six of the 19 serotypes, including Salmonella serovar Enteritidis, were observed in isolates recovered from the eggs. Salmonella serovar Enteritidis strains obtained from a feed sample and egg contents in a layer farm showed pulsed-field gel electrophoresis patterns that were genetically related and belonged to a single phage type, suggesting that the contamination of the farms was linked to the occurrence of salmonellae in feed.     

Effect of cooking on the stability of veterinary drug residues in chicken eggs

ABSTRACT

The available information on drug residue stability in chicken egg is scarce. The objective of this study was to evaluate the stability of drug residues in egg under different traditional cooking procedures. Fresh eggs were spiked with different drug concentrations of albendazole (ABZ) and its albendazole sulphoxide (ABZSO) and albendazole sulphone (ABZSO₂) metabolites; flubendazole (FLBZ) and its reduced flubendazole (R-FLBZ) and hydrolyzed flubendazole (H-FLBZ) metabolites; amoxicillin (AMX); and enrofloxacin (EFX) and its ciprofloxacin (CFX) metabolite. The egg samples were cooked in different ways, namely, boiling, microwaving, and omelette making. Drug residue concentrations in egg were quantified by HPLC with UV or fluorescence detectors. ABZ and ABZSO concentrations in egg were not affected by boiling and microwaving, while the omelette processing significantly reduced these molecules. Residues of ABZSO₂ in egg were stable or increased after all cooking procedures. In contrast, FLBZ and its metabolites FLBZ-H and FLBZ-R residues in egg decreased after all treatments. The residue concentration quantified for EFX and CFX did not show significant changes after any cooking method. AMX residues were unstable, with extremely significant drug reduction after all cooking processes. Conventional methods of egg cooking cannot be considered a tool to eliminate all veterinary drug residues.     

饲喂银杏叶超微粉对鸡蛋胆固醇含量的影响

实验旨在研究银杏叶超微粉对鸡蛋胆固醇含量的影响。选择健康55周龄的罗曼白商品蛋鸡192羽,随机分为对照组和实验组共4组,每组3个重复,每个重复16羽,对照组饲喂基础日粮,实验组在基础日粮中分别添加0.60%、0.80%、1.00%的银杏叶超微粉,预试期7d,正试期28d。结果表明:在第7、28d时,添加银杏叶超微粉对蛋重和蛋黄重、蛋黄相对重影响不显著(p>0.05);第14d时,0.60%、0.80%银杏叶超微粉添加组蛋黄重较对照组差异显著(p<0.05),蛋重和蛋黄相对重差异不显著(p>0.05);第21d时,0.80%、1.00%银杏叶超微粉添加组蛋黄重和蛋黄相对重较对照组差异显著(p<0.05),蛋重差异不显著(p>0.05)。整个实验期,蛋黄胆固醇含量和鸡蛋胆固醇含量较对照组差异显著(p<0.05),在第21d时,0.80%银杏叶超微粉添加组呈现极显著差异(p<0.01),实验至28d时,银杏叶超微粉对鸡蛋胆固醇含量的影响趋于平稳。本实验表明银杏叶超微粉对降低鸡蛋胆固醇具有一定的促进作用,且以0.80%添加量为效果最佳。      

分光测色计在β-胡萝卜素微胶囊干粉中的应用研究

β-胡萝卜干粉1%CWS是一种经微胶囊技术制备而成的、可冷水溶解的、便于使用的产品。其基本色调为黄色,主要适用于水基食品、速溶食品、布丁、糖果和乳制品等的着色和营养强化。本文介绍了分光测色剂的测量方法及应用,并用该仪器对不同浓度的β-胡萝卜素干粉1%CWS水溶液进行颜色检测,得出了代表其颜色的L*,a*,b*值的范围,建立了该产品的颜色控制标准。结果为:β-胡萝卜素干粉1%CWS 20ppm水溶液的L*,a*,b*值范围依次为68 78、22 27、113 126;200ppm水溶液的L*、a*、b*值范围依次为45 52、23 29、74 85。     

南北方鸡蛋、各壳系鸡蛋、洋鸡蛋与土鸡蛋之间营养差异研究

对南北方鸡蛋、各壳系(褐壳、粉壳、白壳)鸡蛋、洋鸡蛋和土鸡蛋之间在蛋壳、蛋清、蛋黄占全蛋质量百分比,蛋清、蛋黄及全蛋的含水量,卵磷脂、胆固醇、粗脂肪含量;蛋清、蛋黄及全蛋蛋白质含量等指标上是否有显著差异进行了实验测定,为消费者科学地选购鸡蛋提供参考.结果表明:三种不同壳系的鸡蛋中褐壳鸡蛋的粗脂肪、卵磷脂、胆固醇和蛋白质含量均最高,且总含水量最低,说明单位质量褐壳鸡蛋所含干物质量更高.洋鸡蛋和土鸡蛋在各项指标中差异较大,但同为南方或同为北方的洋鸡蛋和土鸡蛋在各项指标中差异多为不显著,并且只要是洋鸡蛋就比相应土鸡蛋的蛋清多、蛋壳薄、全蛋含水量高.总体上南方鸡蛋优于北方鸡蛋.     

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。     

Vitamin A and carotene in animal nutrition

Vitamin A, an unsaturated 20 carbon cyclic alcohol, subserves a number of important physiological functions. However, the biochemical basis of these roles is not well understood. The main sources of retinol are liver, egg yolk and milk fat. Several carotenoids show vitamin A activity. The conversion of beta-carotene to retinol is affected by copper-containing dioxygenase and zinc-containing retinene reductase. The efficiency of conversion varies in different species. The latter is defined in units as the daily dose required to produce a weight gain of 3 g/week in young rats between the 4th and 8th week. Retinol is unstable on exposure to light or heat, particularly in the presence of heavy metal ions and water. Much recent work has focused on the absorption, metabolism and excretion of vitamin A. It is now recognized that plasma vitamin A levels do not reflect the nutritional status except in severe hypo- and hypervitaminosis A. Also, many dietary factors may influence vitamin A metabolism. These basic and applied aspects of vitamin A are reviewed.     

腌制前清洗消毒对咸蛋游离氨基酸的影响

目的 脏蛋加工会造成咸蛋黄黑圈、变质等问题,研究清洗消毒对咸蛋黄游离氨基酸的影响。方法 在鸭蛋生产后立即进行甲醛和臭氧消毒清洗,测定了咸蛋游离氨基酸,分析了其种类和含量差异、各呈味氨基酸含量和味道强度值差异,探讨其对咸蛋黄风味和滋味的影响。结果 咸蛋游离氨基酸种类无显著变化,对氨基酸相对含量有一定影响,总游离氨基酸含量、必需氨基酸、呈味氨基酸比对照组分别下降3.41%、12.07%,2.23%、11.38%,2.4%、11.2%。结论 甲醛和臭氧应用于鸭蛋清洗消毒后腌制咸蛋具有可行性,综合考虑清洗对咸蛋（黄）风味的影响,臭氧对风味不利影响小于甲醛,同时可减轻蛋腥味,优选采用2 g/ m3的臭氧清洗消毒腌制前的鸭蛋60 min。     

Effect of processing and oil type on carotene bioaccessibility in traditional foods prepared with flour and puree from orange-fleshed sweetpotatoes

Consumption of Orange-Fleshed sweetpotato (OFSP) and products as source of provitamin A is being promoted to tackle vitamin A deficiency (VAD) in sub-Saharan Africa. However, limited information is available on β-carotene retention in foods and delivery after digestion. The study assessed carotene retention and bioaccessibility following in vitro digestion on traditional foods having OFSP among the ingredients. Sunflower oil, margarine and beef fat were evaluated on their effect on β-carotene bioaccessibility. Porridge and chapatis were prepared with either OFSP puree or flours in the formulations. Carotene retention was highest in chapatis (83%) as compared to porridge (65%). Micerallisation efficiency of all-trans β-carotene was comparable between similar products but greater in chapatis (62%) than porridge (11%). Sunflower oil had the highest all-trans β-carotene bioaccessibility compared to margarine and beef fat. The results support the promotion of consumption of OFSP-based products as good source of provitamin A to fight VAD.