首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
鲜牛肉冷藏保鲜技术研究   总被引:1,自引:0,他引:1  
用正交试验的方法,研究了复合抗氧剂、植酸和多聚磷酸钠对鲜牛肉在冷藏条件下的保鲜效果。结果表明:用5.0%复合抗氧剂、0.2%的植酸、0.6%多聚磷酸钠配制而成的复合保鲜剂喷洒于牛肉表面,用普通塑料膜或复合塑料膜真空包装后,于0~4℃的条件下贮藏38 d,其各项指标仍符合国家鲜肉一级鲜度卫生标准。  相似文献   

2.
桃变温压差膨化干燥预处理工艺研究   总被引:1,自引:0,他引:1  
本文对桃变温压差膨化干燥的预处理工艺进行优化研究。对预干燥温度进行筛选,并研究了氯化钙、抗坏血酸、柠檬酸3种不同护色试剂,果葡糖浆、麦芽糖醇、麦芽糖浆和牛奶4种不同浸渍液对桃变温压差膨化干燥产品色泽、质构等相关品质的影响。结果表明:预干燥温度确定为80℃,在此温度下原料干燥速度较快,色泽较好;2.5%柠檬酸对保持产品的色泽有显著作用;25%麦芽糖醇糖液浸渍有利于产品色泽、硬度、脆度等相关品质的提高。  相似文献   

3.
付立新 《核农学报》2002,16(2):122-124
利用6 0 Coγ射线辐照液态发酵法糖化酶生产的白酒 ( 55℃ )。处理剂量为 0(CK)、1 0、2 0、4 0kGy,剂量率为 1 78Gy min。辐照后室温贮存 3 0d ,检测其理化及感官指标。表明经γ射线辐照的白酒 ,其有益成分均有不同程度增加 ,感官指标也明显优于对照组。将不同剂量辐照的白酒与未辐照的白酒经不同的比例混合 ,筛选理化指标及感官指标较好的酒样。表明以 2 0kGy3 0 % +4 0kGy3 0 % +CK40 %较为理想 ,且混合后贮存 3个月效果更好  相似文献   

4.
为提高柠檬酸修复土壤重金属离子的能力,设计合成新型绿色柠檬酸基表面活性剂柠檬酸-1-酰胺二乙烯三胺,用FT-IR研究其结构,并探究其表面性能。结果表明,新型绿色柠檬酸基表面活性剂的临界胶束浓度低于柠檬酸,其稳泡力、起泡力及亲水亲油平衡值优于柠檬酸。同时开展表面活性剂浓度、pH值、振荡时间、Ca2+浓度影响表面活性剂对土壤重金属污染去除率的研究,结果表明,柠檬酸-1-酰胺二乙烯三胺对重金属去除率随浓度、振荡时间的增加而升高;随离子强度、pH值的增加而降低。柠檬酸-1-酰胺二乙烯三胺去除Cd2+、Pb2+离子的最佳工艺为:质量分数5.5%,pH值3.0,振荡时间10h,Ca2+离子浓度0.4mol/L。在此条件下,2种表面活性剂对土壤中Cd2+、Pb2+离子去除率均达最大,柠檬酸-1-酰胺二乙烯三胺对Cd2+、Pb2+离子最大去除率分别为69.25%和98.59%,去除效果优于柠檬酸。  相似文献   

5.
高压处理对牛肉感官特性与食用品质的影响   总被引:13,自引:4,他引:13  
通过对宰后牛肉施加250 MPa的压力处理,分析测定处理后牛肉在贮藏期间理化指标的变化,研究了高压处理对牛肉感官品质的影响。试验结果表明高压处理能明显降低牛肉的剪切力和改善牛肉的嫩度(P<0.01),高压嫩化的效果与肌肉的部位密切相关,压力处理对背最长肌和里脊的嫩化作用最明显。压力处理后牛肉的可溶性物质含量有所增加,但在贮藏后期差异不显著(P>0.05),压力处理对牛肉中的游离氨基酸的影响不明显(P>0.05),这也表明压力处理对牛肉风味的贡献与自然成熟的作用相近。通过研究可以得出结论,在室温下用250 MPa的压力处理宰后热剔骨(6小时以内)真空包装的牛肉10 min,0~4℃冷藏条件下贮存2~3 d,可获得嫩度好、其它感官指标不明显低于低温吊挂成熟7~10 d的产品。  相似文献   

6.
不同CO2浓度下鸡蛋呼吸仿真分析及验证   总被引:2,自引:2,他引:0  
贮存环境中CO_2浓度对鸡蛋呼吸作用及新鲜度变化具有重要影响,为了进一步考察在不同CO_2浓度下鸡蛋呼吸释放CO_2的扩散及新鲜度变化情况,该研究测定贮存在温度为25℃、相对湿度为65%、CO_2体积分数分别为1.5%、3.0%、4.5%及空气(对照组)环境下鸡蛋呼吸和新鲜度,利用FLUENT软件完成不同CO_2浓度下鸡蛋第1天呼吸释放CO_2的扩散过程仿真。结果表明,利用Fluent软件计算所得气体速度值和试验值基本一致,模拟值与实测值相对误差在4%~9%。不同CO_2浓度下鸡蛋释放CO_2的扩散过程符合重气扩散的特点,其扩散方向受到CO_2浓度的影响,且随着贮存环境中CO_2浓度的增加,鸡蛋呼吸释放CO_2的扩散量和扩散速度逐渐变小,呼吸得到抑制。再通过分析贮存过程中不同CO_2体积分数下鸡蛋呼吸强度和新鲜度变化得出,对照组1.5%CO_2与3.0%CO_2下的鸡蛋呼吸强度和新鲜度具有显著差异(P0.05),当贮存环境中CO_2体积分数达到3.0%时,对鸡蛋呼吸强度的抑制效果不再明显,且新鲜度变化保持不变。3.0%CO_2和4.5%CO_2体积分数下贮存鸡蛋20 d,其新鲜度等级仍在AA级以上,综合经济因素,3.0%CO_2保鲜鸡蛋效果较优。该研究可为鸡蛋呼吸和气调保鲜技术提供理论及数据基础。  相似文献   

7.
贾莹  胡志和 《核农学报》2016,(5):941-948
以蓝莓饮料中花青素的稳定性为指标,研究不同杀菌方式和包装的透光程度对蓝莓饮料中花青素稳定性的影响。结果表明,蓝莓原汁添加量200g·L~(-1),蔗糖添加量70g·L~(-1),柠檬酸添加量1.1g·L~(-1),柠檬酸钠添加量0.3g·L~(-1)时,蓝莓饮料的p H较稳定,适口性较好。采用高温瞬时杀菌(121℃,10s)、常压下100℃杀菌12min后灌装和灌装后100℃杀菌14min的杀菌方式,花青素保留率分别为83.20%、78.21%、80.83%。在全标(瓶体遮盖率96%)、半标(瓶体遮盖率60%)和裸标(瓶体遮盖率0)3种包装方式下,花青素保留率分别为91.58%、89.15%、86.16%。因此,在高温瞬时杀菌(121℃,10s)和全标包装条件下贮存,有利于维持花青素的稳定性。本研究为蓝莓饮料的生产及贮存提供了参考。  相似文献   

8.
真空预冷结合微孔膜包装对鲜枸杞贮藏品质的影响   总被引:1,自引:1,他引:0  
为了延长鲜枸杞贮藏保鲜期,该研究通过真空预冷结合微孔膜包装对鲜枸杞的贮藏品质进行研究,设置不同预冷终温(2、4、6℃)和终压(800~1 000、1 000~1 200、1 200~1 500Pa)对鲜枸杞进行真空预冷处理,通过比较真空预过程中鲜枸杞失重率、蜡质层和呼吸强度指标来确定较优工艺参数;之后将真空预冷较优工艺参数下的鲜枸杞用微孔膜包装后在(-1±0.5℃)的冷库中进行贮藏,以微孔膜包装处理和未经任何处理的鲜枸杞作为对照组,比较贮藏过程中硬度、可溶性固形物(Total Soluble Solids,TSS)、色差、呼吸强度、过氧化氢酶(Catalase,CAT)活性指标来综合分析不同处理对鲜枸杞贮藏品质的影响。结果表明:终温6℃和终压800~1 000Pa对鲜枸杞失重率影响较小;终温6℃和终压1 200~1 500Pa对鲜枸杞内表皮结构损伤较小;终温2℃和终压800~1 000Pa鲜枸杞呼吸强度最低,综合考虑3个指标,终温6℃,终压1 200~1 500 Pa为鲜枸杞真空预冷较优工艺参数;在贮藏期间,真空预冷结合微孔膜包装与其他两组相比较,可有效延缓鲜枸杞硬度和TSS下降,降低呼吸强度,抑制色差变化和CAT活性的下降(P0.05)。该研究为鲜枸杞贮藏保鲜提供新方法。  相似文献   

9.
温度、水分和施肥对甜菜黑土氮素迁移转化的影响   总被引:2,自引:1,他引:1  
以东北甜菜主产区的黑土为材料,采用模拟土柱方法,研究了不同温度(5℃和20℃)、水分(10%,20%和30%)和施肥(尿素)条件对甜菜0—90cm土层土壤无机氮(NH4+-N和NO3--N)迁移转化的影响。结果表明:在整个培养期内,温度和水分对不同施肥处理、不同土层土壤NH4+-N和NO3--N含量的影响不同。不施肥土壤NH4+-N和NO3--N含量在不同水分和温度下均无显著差异。不同温度和水分条件下施肥处理各土层NH4+-N、NO3--N平均含量均随土层深度增加而下降,在相同温度条件下,土壤水分为20%时为甜菜土壤矿化和硝化作用的最适水分,而10%水分时,0—15cm土层土壤硝化作用受到明显抑制。施肥明显增加0—15cm土层NH4+-N、NO3--N含量,分别与不施肥相比增加2.71~16.65倍和1.04~9.05倍。5℃时,NH4+-N、NO3--N在土柱内的迁移距离和硝化作用主要发生在0—15cm土层内;20℃时,主要发生在0—15cm和0—50cm土层内。施肥与不施肥土壤NH4+-N含量与温度、水分均呈负相关,NO3--N含量和硝化率(Nr)呈正相关,多因素统计分析表明,温度和水分的提高可以增强施肥土壤的氮素转化,温度、水分和施肥三者对土壤NH4+-N、NO3--N含量迁移有交互作用,但是对土壤氮素的转化没有显著影响。  相似文献   

10.
冷冻虾仁辐照保鲜研究   总被引:9,自引:8,他引:9  
研究了出口冷冻虾仁的辐照保鲜效果 ,并对辐照冷冻虾仁的微生物指标、主要营养成分、理化指标进行了检测。结果表明 :3~ 5kGy的辐照剂量可以杀灭冷冻虾仁中 99%以上的微生物 ,经 1~ 9kGy剂量辐照 ,虾肉中大多数氨基酸含量均有增加 ,其总量明显高于对照 ,增加幅度在 0 33%~ 2 4 6%之间 ,辐照后挥发性盐基氮的含量降低 ,有害重金属元素含量辐照前后无显著差异 ,辐照后虾仁在 - 7℃下贮存 ,保鲜期比对照延长 6个月。  相似文献   

11.
【目的】以富士(Fuji)、 秦冠(Qinguan)嫁接在平邑甜茶(Malus hupehensis Rehd.)上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水(ZZ)、 低氮正常水(DZ)、 正常氮干旱(ZG)、 低氮干旱(DG)。氮素和水分均设置两个水平,分别为正常氮(6 mmol/L NO-3-N)、 低氮(0.3 mmol/LNO-3-N)、 正常供水(保持盆中砂子相对含水量为饱和含水量的80%~85%)、 干旱处理(保持盆中砂子相对含水量为饱和含水量的60%~65%)。【结果】富士和秦冠的生物量(茎和叶)、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水(ZZ)>低氮正常水(DZ)>正常氮干旱(ZG)>低氮干旱(DG),并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水(ZZ)>低氮正常水(DZ)>正常氮干旱(ZG)>低氮干旱(DG); 氮、 钾元素含量在植株各部位的分布顺序依次是叶>根>茎,磷元素则是根>叶>茎;光合氮素利用效率(PNUE)和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水(DZ)处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱(DG)处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。  相似文献   

12.
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.  相似文献   

13.
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,  相似文献   

14.
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.  相似文献   

15.
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.  相似文献   

16.
We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.  相似文献   

17.
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,  相似文献   

18.
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,  相似文献   

19.
Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.  相似文献   

20.
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号