不同包装形式的乳粉的贮存稳定性

研究不同包装材料(铝箔袋:聚酯(polyethylene terephthalate,PET)/聚酰胺(polyamide,PA)/铝箔(aluminum foil,AL)/聚乙烯(polyethylene,PE);杯装胶囊1:聚丙烯(polypropylene,PP)/乙烯-乙烯醇共聚物(ethylenevinyl alcohol copolymer,EVOH) /PP;杯装胶囊2:PP包装的乳粉,在恒温恒湿培养箱内37℃或42℃、相对湿度75％的条件下加速贮存12周,乳粉水分含量、水分活度(water activity,aw)、色泽及硫代巴比妥酸(thiobarbituric acid,TBA)值的变化.结果表明:相同条件下,铝箔袋包装的乳粉水分含量、aw在加速贮存实验过程中处于相对稳定,色差△E和TBA值随着加速时间的延长而增高;胶囊包装的乳粉在加速贮存实验期所有指标(水分含量、aw、亮度值￡*、红度值a*、黄度值b*、△E及TBA值)都持续性增高,且胶囊1乳粉各指标的变化幅度小于胶囊2.结论:铝箔袋包装对乳粉的保护性最好,胶囊1次之,胶囊2最差,开发胶囊乳粉优选胶囊1材质.     

赤星菌弱毒株TBA16对烟草抗赤星病诱导作用条件的研究

用病菌弱毒株TBA16的孢子按4种方法对烟苗进行诱导处理时,叶面喷洒和叶面悬滴诱导处理法可以明显地诱导烟草对赤星病的系统抗性。在叶面悬滴诱导中,诱导抗性在第6天开始表现,第12天达到最高并持续到第21天。重复诱导可使诱导抗性持续期延长,并使抗性程度提高,经3次重复诱导后抗性诱导效应可以由36%-83%提高到100%,4次重复诱导使抗性持续期由21天延长到42天以上。诱导抗性表现程度还与挑战按种后的保湿时间有关,并明显地受温度影响,在24℃左右抗性诱导效应最高,在30℃和16-20℃下效应减弱51.3%-56.4%。病菌毒素诱导比孢子诱导的效果高35%-77%,用叶面悬滴法诱导时,毒素的抗性诱导效应最高可达到100%。     

不同储藏条件下杜洛克与长白猪肌肉pH、糖原、乳酸含量及TBA值比较

研究测定了杜洛克及长白猪屠宰后10 h、4℃冷藏6 d、-20℃冷冻5 d的肌肉p H、糖原、乳酸含量和TBA值（硫代巴比妥酸值）。结果表明,宰后10 h,宰后时间对杜洛克及长白猪肌肉p H、乳酸影响极显著,对糖原、TBA值影响不显著。猪种间比较,第3小时和第5小时的p H杜洛克分别比长白猪高4.37%（P〈0.01）和3.93%（P〈0.05）;第0.75小时、第2小时和第5~7小时的肌糖原含量杜洛克分别比长白猪高166.83%（P〈0.01）、120.59%（P〈0.01）、117.02%（P〈0.05）、154.31%（P〈0.01）、147.23%（P〈0.05）;宰后45 min、第2~4小时和第7~8小时的乳酸含量长白猪分别比相同时间点的杜洛克猪高37.99%（P〈0.05）、27.46%（P〈0.05）、68.90%（P〈0.01）、33.19%（P〈0.05）、52.97%（P〈0.01）和47.05%（P〈0.05）。4℃冷藏条件下,储存时间对杜洛克猪肌肉p H、糖原含量、乳酸含量和TBA值影响不显著,对滴水损失影响显著;对长白猪肌肉p H、糖原含量影响不显著,对滴水损失、乳酸含量和TBA值影响显著。4℃冷藏条件下储藏6 d,肌肉p H、糖原含量和TBA值品种间差异不显著;第48小时乳酸含量杜洛克比长白猪高25.10%（P〈0.05）;第24小时和第48小时滴水损失长白猪分别比杜洛克高160.96%（P〈0.05）和60.06%（P〈0.05）。-20℃冷冻条件下,储存时间对杜洛克猪肌肉p H影响显著,对解冻失水率、糖原、乳酸、TBA值影响不显著;对长白猪肌肉p H、解冻失水率、糖原及乳酸含量影响不显著,对TBA值影响显著。-20℃冷冻条件下储藏5 d,杜洛克和长白猪相同时间点的p H、糖原含量、TBA值差异不显著;第48小时乳酸含量杜洛克比长白猪高23.71%（P〈0.05）,第120小时乳酸含量长白猪比杜洛克高10.78%（P〈0.05）;第24小时和第72小时解冻失水率长白猪分别比杜洛克高186.85%（P〈0.05）和127.20%（P〈0.05）。     

Magnesium deficiency induced oxidative stress and antioxidant responses in mulberry plants

The aim of the study was to implicate induction of oxidative stress and antioxidative responses with the effects of Mg deficiency in mulberry plants. Mulberry (Morus alba L.) cv. Kanva-2 plants grown in hydroponics were subjected to deficiency of Mg. Mg-deficient plants developed visible symptoms—deep interveinal chlorotic mottling and necrosis in the older and middle leaves. The decreases in the dry matter yield of plants and concentrations of sugars and starch in the leaves of Mg-deficient plants are suggestive of decreased photosynthetic activity. Mg-deficiency decreased concentrations of photosynthetic pigments, and increased concentrations of H₂O₂ and ascorbate and activities of antioxidative enzymes—peroxidase (POD), ascorbate peroxidase (APX) and superoxide dismutase (SOD). The results suggest induction of oxidative stress by enhancing generation of ROS and inducing alterations in redox status, accompanied by activation of antioxidant machinery including induction of some new SOD isoforms in Mg-deficient mulberry plants. Despite significant increase in H₂O₂, lipid peroxidation was decreased in Mg-deficient plants.     

腌制鳙鱼片在冷藏过程中品质变化规律的研究

文章研究了腌制鳙（Aristichthys nobilis）鱼片在冷藏过程中的品质变化规律.将鱼片用质量分数为2％的食盐进行腌制处理,置于4 ℃下冷藏,通过测定感官指标和硫代巴比妥酸（TBA）值、色泽、脂肪酸组成等理化指标,探究腌制对鳙品质的影响.结果显示,腌制组鱼片的货架期为15 d,对照组为9d;腌制组和对照组的pH分别在第9天和第3天达到最低值,分别为6.73和6.81;腌制组TBA值的增长速度显著高于对照组;与对照组相比,腌制鱼片的亮度低,肉色偏红、偏蓝;腌制组鱼片的总多不饱和脂肪酸（∑PUFA）,尤其是n-3系列多不饱和脂肪酸的含量明显低于对照组（P＜0.05）.结果表明,腌制虽然能够延长鳙鱼片冷藏时的货架期,但是会加速鱼片变色,促进脂肪酸尤其是n-3系列多不饱和脂肪酸的氧化.     

鱼类饲料油脂氧化酸败分析及对饲料质量影响探讨

本对四种油脂（大豆油脚、鱼油、新鲜豆油和熟豆油）和五种鱼用颗 粒饲料（市售）进行了过氧化值和硫代巴妥酸（TBA）值的分析测定；并测得大豆油脚贮藏前后（10天）氧化酸败值的变化。     

在不同贮藏温度下鲢肌肉鲜度的变化

以总挥发性盐基氮(TVB-N)和硫代巴比妥酸值(TBA)作为肌肉鲜度的评定指标,研究在冷藏(4℃)和冷冻(-18℃)条件下鲢(Hypophthalmichthys molitrix)背部和腹部肌肉鲜度的变化情况。结果表明,在贮存过程中,鲢背部和腹部肌肉的TVB-N和TBA均符合一级反应动力学模型;随着温度的升高,反应速率加快;在4℃条件下,鲢肌肉一级鲜度的保质期为27～38 h,二级鲜度为51～65 h,到81～88 h腐败变质;在-18℃条件下,鲢肌肉一级鲜度的保质期为11～18 d,二级鲜度为36～43 d,到73～77 d腐败变质;在同一贮存时间,腹部肌肉的TVB-N和TBA均高于背部;并且,鲢肌肉的TVB-N与TBA呈极显著(P<0.01)的正相关关系。     

Ion-exchange microchromatography and thiobarbituric acid colorimetry for the measurement of canine glycated hemoglobins

Nonenzymatic glycation of hemoglobin is a slow, continuous, and irreversible process which takes place during the whole lifespan of the erythrocyte. When hemolytic diseases are ruled out, the levels of glycated hemoglobins reflect the time-averaged serum glucose concentration for the preceding weeks. Canine hemoglobin also binds physiologically to intraerythrocytic glucose to form a glycated fraction which provides information on the animal's long-term glycemic status. This study describes an overall evaluation of ion-exchange microchromatography and thiobarbituric acid (TBA) colorimetry for the measurement of canine glycated hemoglobins. The intra- and inter-assay coefficients of variation (CVs) found were less than 5% in normal and diabetic canine samples, and both assays proved linear over the analytical range tested, which was wide enough to include the expected clinical values. Under our laboratory's conditions, the reference range for HbA(1) was 5.82 +/- 0.62% and for HbA(1)c was 2.35 -/+ 0.47%. Sample stability was lower using the ion-exchange procedure, with increases in HbA(1) observed after 4 days in whole blood and hemolysates stored at room temperature, after 12 days in whole blood stored at 4 degrees C, and after 7 days in hemolysates stored at 4 degrees C and -20 degrees C. In the case of TBA colorimetry, whole blood was stable for at least 21 days at room temperature and at 4 degrees C, and hemolysates were stable for 18 days at room temperature, at least 21 days at 4 degrees C, and up to 3 months at -20 degrees C.     

茶多酚对单次漂洗鱼糜品质的影响

以一次漂洗的海水鱼鱼糜为原材料,茶多酚为添加剂,研究不同的茶多酚浓度对鱼糜的凝胶强度、白度、失水率和TBA值等品质的影响。结果表明：添加0.15-0.20 %的茶多酚,可以获得贮藏时间较长、凝胶强度高且减少污水污染和浪费海水鱼鱼糜。     

甲基叔丁基醚(MTBE)的生物降解特性研究

采用摇瓶振荡法,利用自行富集驯化培养的混合微生物对甲基叔丁基醚（MTBE）好氧降解规律进行了研究,讨论温度、pH值、MTBE初始浓度、接种量对MTBE降解率的影响。结果表明,以MTBE为碳源的微生物生长极其缓慢,使得MTBE的生物降解性较差．本研究条件下的最高降解率为48．88％,且在约200h的降解时间内没有发现中间产物叔丁醇（TBA）的进二步降解。MTBE降解规律可用Monod-no—growth模型很好描述,其基本降解动力学参数为μmax=0.085h^-1,Ks=381.70mg·L^-1。