食用槟榔的辐照灭菌研究初报

食用槟榔经 6 0kGy辐射剂量照射后 ,细菌总数低于 1 0 2 CFU/g ,8 0kGy可使细菌总数低于检测水平。经 6～ 8kGy处理的食用槟榔 ,室温下 ( 2 0～ 3 5℃ )保质期可达3个月 ;辐照处理对食用槟榔的口味、咀嚼性没有明显影响。     

电子束辐照榨菜保鲜研究

本研究表明 ,天然榨菜经电子束 (8MeV) 3kGy辐照 ,在南京地区 9～ 1 0月常温(2 0～ 2 5℃ )下保质期为 3个月。辐照榨菜的卫生指标、感观指标、全N以及Pb、Hg、As的含量均符合国家标准 ,辐照对榨菜氨基酸 ,粗纤维含量无显著影响     

扬州豆腐干风味制品核辐照综合保质技术研究

豆腐干是扬州名菜大煮干丝的原料,过去由于沿用传统工艺制作,保质期短,外地淮扬菜馆难以经营,本研究通过改进生产工艺,对产品实施真空包装和8kGy的辐照处理,可实现4℃保藏3个月的目标。将此技术应用于茶香干、酱干相关制品,结果表明,处理后的产品25℃可保藏3个月,4℃可保藏4个月,应用于大煮干丝可在4℃下保藏2个月。     

面包糠辐照杀菌工艺研究

研究了面包糠辐照杀菌工艺。结果表明 ,剂量均匀性和堆码高度与产品转向有着密切关系 ,杀菌效果与剂量呈正相关 ,色泽与剂量呈负相关。面包糠粗蛋白质、粗脂肪、碳水化合物、微量元素和 1 7种氨基酸含量辐照前后无显著差异 ;提出了适宜杀菌剂量为 6～ 1 0kGy ,可将面包糠保质期延长至 1年。     

辐照对月饼卫生和品质的影响

本文研究了辐照和抗氧化剂对月饼贮藏过程中卫生质量和品质的影响。通过对不同条件下月饼的过氧化值、酸价、霉菌、大肠菌群、菌落总数和感官指标的分析得出:8kGy的辐照处理能够在常温下将月饼保质期延长至3个月。试验结果还表明添加茶多酚可有效防止月饼因辐照而引起的脂质氧化。     

检测睾酮、孕酮、雌酮与雌三醇的双抗体酶免疫分析法

本文报道了自制的试剂建立了检测睾酮、孕酮、雌酮和雌三醇的双抗体酶免疫分析法。实验表明 ,这些测定具有很高灵敏度 (最小可测量为 0 1～ 1pg 孔 ) ,标准曲线范围为 0～ 40pg 孔 ;同相关类固醇激素 (孕酮、孕烯醇酮、睾酮、雄酮、雌酮、雌三醇和皮质酮等 )的交叉反应率一般在 0 1 %以下。测定的批内和批间变异系数分别在5 8%～ 7 2 %与 9 5%～ 1 0 5% (n =8)范围内。向血中添加激素标准品后的回收率在 94%～ 1 1 0 %范围内。用自制防腐剂处理后 ,液态抗体 (包括第二抗体 )、酶标记物和已包被第二抗体的滴定板可保持活性 5～ 1 2个月或更久 ( 4℃～ -2 0℃ )。此测定可节约激素特异抗体 4～ 1 0倍。初测人和动物的血、奶、尿样品表明所建立的 4种测定方法可分别用于人和动物体液中睾酮、孕酮、雌酮和雌三醇的定量检测     

重金属胁迫对水稻叶片过氧化氢酶活性和同功酶表达的影响

本文报道了浓度为 0 0 5～ 2 0mM的重金属Cu、Cd、Hg胁迫对 3个不同类型水稻品种幼苗叶片过氧化氢酶 (CAT)活性和同功酶表达的影响。结果表明 :( 1 )在胁迫浓度为 0 0 5～ 2 0mM范围内 ,CAT活性随Cu和Cd浓度的增高而持续下降 ;CAT活性随Hg浓度的增高表现为先下降 ,再略有升高 ,然后又明显下降 ,表明浓度为 0 0 5～ 2 0mM的Cu、Cd、Hg胁迫显著抑制 3个不同类型水稻品种幼苗叶片CAT活性。( 2 )应用聚丙烯胺浓度梯度电泳对CAT同功酶分析显示 ,正常情况下水稻叶片中有 1～ 2个CAT同功酶的表达 (武育粳叶片中表达 2个 ,扬稻 6号和汕优 81 8叶片中表达1个 )。 0 1mM的Cd胁迫能诱导武育粳叶片 ,0 1mM的Cd和Hg胁迫能诱导扬稻 6号叶片表达 1个新的CAT同功酶。尽管如此 ,正常表达的CAT同功酶仍受到重金属Cu、Cd、Hg胁迫的抑制     

风味豆制品辐照贮藏保鲜技术研究

用聚乙烯复合膜抽真空包装 (5 0g 袋 )的风味豆制品经 5～ 1 0kGy照射 ,在常温(2 5℃ )条件下贮藏 30d,0～ 7℃条件下贮藏 90d ,经感官品评和微生物检测 ,结果表明 ,细菌总数低于 5× 1 0 4 个 g,大肠菌群 <30个 1 0 0g,符合国家卫生质量标准(GB2 71 1 -81 ) ,保持豆制品原有的色泽、香味 ,无异味 ,质地细腻 ,有弹性 ,无胖袋。蛋白质、脂肪含量辐照前后无明显变化 ,包装材料厚度为 0 0 7～ 0 1 0mm为宜。     

赞皇大枣组织培养快速繁殖技术研究

为解决赞皇大枣组织培养快速繁殖问题 ,通过对启动培养、增殖培养、壮苗培养和生根培养 4个阶段培养条件的研究 ,筛选出该品种的最佳启动、增殖、壮苗和生根培养基 ,分别为 :MS+6-BA0 5mg L +IBA0 1mg L ;MS +6-BA1 5mg L +IBA0 1～0 2mg L ;MS +KT0 5mg L +NAA0 2mg L ;1 2MS+IBA0 6mg L +NAA0 2～ 0 3mg L。     

花药组织培养和小麦×玉米杂交技术应用于产生小麦单倍体的比较研究

两个春小麦品种意塔和帕旺的花药组织培养和小麦×玉米杂交技术产生单倍体的效果不同。不同基因型花药诱导愈伤组织的诱导率从 9 4%到 1 9 7%不等 ,不同基因型所产生的再生株数量亦不同 ,两个小麦品种都有绿苗和白化苗产生 ,绿苗诱导率自 1 3%到 5 0 %。分别利用小麦×玉米杂交技术能有效诱导两个春小麦品种单倍体 ,杂交结实率为 80 2 %～95 1 % ,但只有 1 0 9%～ 1 4 6%的籽粒含有幼胚 ,其中 95 %以上的幼胚可发育成绿苗。每 1 0 0个杂交小花中平均可生成 1 0 5个到 1 4 0个绿苗 ,不产生白化苗 ,染色体亦不自然加倍。     

适宜电子束辐照延长醉泥螺货架期及蛋白质保持

为探明电子束辐照对醉泥螺的杀菌效果及辐照后醉泥螺感官品质与蛋白质营养价值的变化,为生食醉泥螺的辐照保鲜应用提供理论依据。以生食醉泥螺为研究材料,研究不同剂量电子束辐照对醉泥螺菌落总数、感官评分、蛋白质含量及其氨基酸组成的影响,并分析辐照后醉泥螺在冷藏和常温贮藏条件下的货架期变化。结果表明：1）经1～9 kGy剂量电子束辐照,醉泥螺的色泽和形态几乎没有变化,但7、9 kGy剂量组醉泥螺产生异味;2）辐照剂量越高,杀菌效果越好,当醉泥螺的初始菌落总数为1200 cfu/g时,菌落总数降至初始值10%所需的辐照剂量D10为3.46 kGy;3和5 kGy剂量的辐照对醉泥螺的抑菌效果明显,无论是冷藏还是常温贮藏,360 d内菌落总数均未超过5000 cfu/g;3）辐照对醉泥螺蛋白质含量无明显影响(P?0.05),不改变醉泥螺的限制性氨基酸种类,但经1、3、5 kGy辐照后,氨基酸总量、必需氨基酸总量及各必需氨基酸的氨基酸评分增加;4）结合电子束辐照对醉泥螺菌落总数及感官评分的影响,辐照剂量以3 kGy为宜,醉泥螺保质期冷藏条件下由对照组的5个月延长至12个月,常温条件下由对照组的不到1个月延长到3个月。该结果能为电子束辐照保鲜醉泥螺提供依据。     

醉蟹辐照剂量处理的研究

辐射在介质中产生的效应直接依赖于所吸收的辐射能量。为保证“醉蟹辐照保质”项目实施 ,本文从剂量计配制、放取样品位置、辐照时间确定、辐照样品不均匀度、剂量计比对等方面进行了探讨 ,为商业化醉蟹辐照提供一定的参考数据     

Differential detection of shrimp and crab for food labeling using polymerase chain reaction

Shrimp and crab are well-known as allergenic ingredients. According to Japanese food allergy labeling regulations, shrimp species (including prawns, crayfishes, and lobsters) and crab species must be differentially declared when ≥10 ppm (total protein) of an allergenic ingredient is present. However, the commercial ELISA tests for the detection of crustacean proteins cannot differentiate between shrimp and crab. Therefore, two methods were developed to discriminate shrimp and crab: a shrimp-PCR method with postamplification digestion and a crab-PCR method that specifically amplifies a fragment of the 16S rRNA gene. The sensitivity and specificity of both PCR methods were verified by experiments using DNA extracted from 15 shrimp species, 13 crab species, krill, mysid, mantis shrimp, other food samples (cephalopod, shellfish, and fish), incurred foods, and commercial food products. Both PCR methods could detect 5 pg of DNA extracted from target species and 50 ng of genomic DNA extracted from incurred foods containing 10 ppm (μg/g) total protein of shrimp or crab. The two PCR methods were considered to be specific enough to separately detect species belonging to shrimp and crab. Although false-positive and false-negative results were obtained from some nontarget crustacean species, the proposed PCR methods, when used in conjunction with ELISA tests, would be a useful tool for confirmation of the validity of food allergy labeling and management of processed food safety for allergic patients.     

Free radical generation assays: new methodology for accelerated oxidation studies at low temperature in complex food matrices

A novel method for the rapid screening of antioxidant efficacy and oxidative stability in food and feed matrices has been developed. The analyses are described as free radical generation (FRG) assays. The new procedure combines the use of azo-initiators with analytical equipment that is widely used for antioxidant research such as the oxidative stability instrument and the oxygen bomb. The use of initiators instead of high temperatures as a driving force to increase the rate of oxidation improves the correlation between the accelerated screening of foodstuffs and real shelf life. The improved correlation can be mainly explained by the fact that food products are analyzed in their original status, maintaining all interfacial phenomena of the food matrix. Furthermore, the lower temperature of analysis reduces differences between the reaction kinetics of the assay and those of the oxidation during actual shelf life. Consequently, the correlation between the accelerated analysis and shelf life is improved, particularly when compared to accelerated oxidation at high temperatures. The FRG assays could be used successfully to evaluate the efficacy of natural antioxidants in heat-sensitive food products such as emulsions and meat products. A good correlation was observed between the accelerated tests and the oxidation parameters obtained from standard shelf-life evaluation. It was possible to successfully compare the efficacy of several antioxidants and to predict shelf life for these heat-sensitive food matrices.     

贮藏温度对三疣梭子蟹蟹肉风味的影响

为延缓三疣梭子蟹品质劣变,延长其货架期,本试验研究了冰温贮藏、冷藏、冰藏对蟹肉挥发性风味、腺苷三磷酸(ATP)关联物及游离氨基酸含量的影响,并对其呈味物滋味强度值(TAV)及味精当量(EUC)进行分析。结果表明,冰温组蟹肉挥发性风味在贮藏前6 d 无明显变化,而冷藏和冰藏组蟹肉挥发性风味分别在贮藏第2和第4 天开始出现明显变化。冰温组蟹肉肌苷酸(IMP)和腺苷酸(AMP)的滋味强度值、游离氨基酸总量、鲜味氨基酸、甜味氨基酸和甜苦味氨基酸占总游离氨基酸的百分比、EUC均高于同期冰藏、冷藏。组综上所述,冰温贮藏能有效保持蟹肉良好风味,缓解蟹肉风味劣变。本研究结果为冰温贮藏技术在梭子蟹保鲜中的应用提供了一定的理论依据。     

Implications of intraguild predation for sea turtle nest protection

In the United States, raccoons Procyon lotor are often removed from sea turtle nesting beaches to decrease egg mortality. However, raccoons also consume ghost crabs Ocypode quadrata, another common egg predator. Reducing predator populations can benefit secondary predators, inflating total predation pressure and leading to a decline in prey species. We used track and burrow counts to compare raccoon and ghost crab abundance at four beaches in Florida, USA, that differ in management activity and determined predation rates on loggerhead Caretta caretta nests by each predator. Mean raccoon abundance (range 0.12-0.46 tracks plot⁻¹ night⁻¹) and ghost crab density (0.09-0.19 burrows m⁻²) were inversely correlated. Ghost crabs were largest at the site with the fewest raccoons. The stable nitrogen isotope ratios of ghost crabs (mean 9.8‰) were positively correlated with body mass, indicating larger ghost crabs feed at a higher trophic level and suggesting large ghost crabs may consume more loggerhead eggs. The highest rates of egg predation by both predators (31%) occurred where raccoon abundance was lowest and ghost crab abundance was highest, suggesting ghost crab burrows may facilitate predation by raccoons. Our data suggest that predation by raccoons limits ghost crabs and that removing raccoons can increase ghost crab abundance and sea turtle egg mortality. Although predator removal can be effective when nest predation rates are quite high, maintaining moderate raccoon densities may be important for controlling ghost crabs. These results highlight the importance of understanding food web connectivity in developing management strategies to achieve conservation goals, especially when the species of concern are threatened or facing extinction.     

Physiological disorders,bitter rot and other fungal decay of ‘Aroma’ apple fruit stored in controlled atmosphere

Effects of controlled atmosphere (CA) conditions on physiological disorders and fungal fruit decay on apple ‘Aroma’ were investigated. Fruit from three growing seasons were stored at 1% or 2% O₂ (both at 2% CO₂) at either 1°C or 3°C in small research units; controls were kept in the same ventilated rooms at the two temperatures (ambient air). The fruit were removed from storage after four or six months and assessed for fruit decay immediately afterwards and after two weeks at 20°C. Fruit quality parameters were recorded at the end of storage. On a three-year average, fruit stored in CA was less ripe at the end of storage. After both four and six months storage, CA reduced total decay (physiological disorders and fungal decay) by on average 70% and 45%, respectively, compared to storage in ambient air. Senescent breakdown was lower after CA storage for four months, but not after six months and not after simulated shelf life. Soft scald was lower when stored in CA both after cold storage at 1°C and simulated shelf life. After storage at 3°C there was lower incidence of soft scald when stored in CA after four months, but not after six months. For fungal fruit decay in general, there was no effect of low oxygen, however, 2% O₂ gave slightly less bitter rot (Colletotrichum acutatum) than 1% O₂ and significantly less than ambient air after simulated shelf life. Averaged over all oxygen levels, 1°C gave significantly less bitter rot than 3°C. It may be concluded that use of CA for storage of ‘Aroma’ is a good way of reducing development of physiological disorders. However, development of bitter rot seemed to be more influenced by temperature and storage time than by low O₂.     

Procedure to evaluate the stability during processing and storage of a medicated premix and medicated farm feed: erythromycin thiocyanate

In this paper, a stability study of a medicated premix and medicated farm feed containing erythromycin thiocyanate was planned. No drug degradation was detected during the medicated farm feed processing. In the medicated premix stability study, significant drug degradation was detected only at 40 degrees C and 75% relative humidity. Because after 2 years of storage at 25 degrees C and 60% relative humidity no degradation of erythromycin thiocyanate was detected, this period of time is proposed as the premix shelf life. In the medicated farm feed stability study, drug degradation was detected under accelerated conditions, but it was not detected under long-term storage conditions for 3 months. Therefore, the proposed shelf life of the medicated farm feed is 3 months, as this is time enough to be consumed. The planned stability study-storage conditions, testing frequency, and proposed data evaluation-allowed an easy and reliable evaluation of veterinary medicine stability.     

我国大樱桃深加工开发利用研究

大樱桃是深受人们喜爱的水果,但货架期较短,对其进行深加工显得尤为重要。我国大樱桃深加工产品主要有罐头、果脯、果酱、果汁、果酒、果醋等,这些产品中食品添加剂使用较为普遍。为了延长大樱桃产业链、提高产品附加值、促进大樱桃产业提质增效,整理归纳了近年来大樱桃深加工相关技术的研究文献,从果肉、果核和树叶3个方面综述了深加工开发利用研究进展,果肉的深加工主要是制作罐头、果酱、果冻、果汁及复合饮料、果脯、果酒、果醋和色素等,果核的深加工主要是提取大樱桃仁油、黄酮、多糖、蛋白及抗氧化多肽,树叶的深加工主要是提取黄酮和多糖;并针对樱桃深加工中存在的问题提出了今后的主要研究方向。     

蟹脚壳肉分离装置的设计与试验

针对河蟹蟹脚人工壳肉分离劳动强度大、效率低下且蟹肉易污染等问题,设计了一种辊筒挤压式蟹脚壳肉分离装置。该装置通过倾斜的输送滑道将蟹脚输送到一对直径相同、转动方向相反,转速相同的圆柱辊筒之间,利用其挤压作用完成蟹脚的壳肉分离。为确定蟹脚壳肉分离装置的最佳工作参数,以分离效率、得肉率及蟹肉品质为性能指标,以送料角度、辊筒间隙和辊筒转速为影响因素对样机开展了正交试验。结果表明:影响壳肉分离效率的极显著因素为辊筒转速,送料角度和辊筒间隙影响不显著;影响得肉率的极显著因素为辊筒间隙,显著因素为送料角度,辊筒转速影响不显著;影响蟹肉品质的极显著因素为辊筒间隙,送料角度和辊筒转速影响不显著。试验结果表明:最佳工作参数为:送料角度40?,辊筒转速35 r/min、辊筒间隙1.2 mm,在此最优组合参数下,分离率23.1 kg/h,得肉率98.5%,蟹肉品质8.9分,该研究可为后续的设计优化与性能提高提供参考。