肉桂精油对红提葡萄保鲜效果的影响

目的：探究肉桂精油保鲜液在红提葡萄贮藏过程中的保鲜效果。方法：以新鲜红提葡萄为实验对象,在不同的温度和相对湿度条件下,采用不同体积分数的肉桂精油保鲜液对红提葡萄进行处理,并根据烂果率变化找出较优的贮藏条件和肉桂保鲜液体积分数,研究在较优贮藏环境下红提葡萄的风味品质（葡萄糖、可滴定酸）、质构品质（水分含量、硬度）及货架品质（烂果率、质量损失率、呼吸强度）的变化规律。结果：红提葡萄经过0.1%（N-0.1%）、0.5%（N-0.5%）和1.0%（N-1.0%）的肉桂保鲜液处理后发现,2 ℃条件下的红提葡萄烂果率比10 ℃好,而N-1.0%组红提葡萄的烂果率最低,保存效果最理想。通过2 ℃ 3 种相对湿度（50%、70%、90%）条件下品质的测定发现,90%的相对湿度环境更有利于肉桂保鲜液的抑菌保鲜效果。除烂果率低外,在贮藏末期红提葡萄的可滴定酸、葡萄糖、水分含量及硬度都保持在较高水平,分别为1.31%、10.78%、80.68%、1 003 g。同时,红提葡萄的质量损失率和呼吸强度也得到了有效抑制。结论：肉桂精油保鲜液的抑菌保鲜作用在低温、高湿条件下发挥更充分,较高体积分数的保鲜液保鲜效果较好,可以延缓红提葡萄贮藏品质的下降,延长贮藏时间。     

八角提取物对红提葡萄的保鲜效果研究

研究了八角提取物对红提葡萄的保鲜效果。利用不同浓度的八角提取物保鲜液对红提葡萄进行处理,在不同温度(2、10℃)和不同湿度(50%、70%、90%)下贮藏,根据贮藏过程中红提的烂果率、呼吸强度、葡萄糖含量、可滴定酸含量及失重率等的变化筛选出有利于发挥保鲜液保鲜效果的贮藏条件。结果表明在2℃90%湿度条件下红提葡萄的烂果率和失重率最低,呼吸作用最弱,果实中的葡萄糖和可滴定酸含量保存最好,其果粒硬度也相对较大。说明低温高湿的贮藏条件更加有利于八角提取物保鲜液发挥其保鲜作用。     

不同贮藏条件对红提葡萄保鲜效果及 部分品质的影响

目的研究温度和湿度对红提葡萄贮藏品质的关系,确定最适宜的贮藏条件,以保证红提葡萄的采后品质。方法考察3种(20、10以及2℃)温度和3种湿度(50%、70%、90%)贮藏环境中红提的保鲜效果,其中20℃温度下贮藏10 d,10℃2℃温度下贮藏35 d,同时对2℃下3种湿度环境条件下的红提葡萄的风味品质(葡萄糖、果糖、可滴定酸含量)、质构品质(水分含量、硬度)和货架品质(烂果率、失重率)进行测定及对比。结果3种温度及湿度条件下,2℃贮藏环境中的腐烂率普遍较低,保鲜效果最好。通过比较贮藏期间品质的指标变化发现,2℃下湿度为90%时,红提葡萄贮藏28 d后的葡萄糖含量为8.92%,果糖含量为9.01%,可滴定酸含量为1.07%,水分含量为82%,硬度为1007 g,失重率为0.38%,烂果率为6.67%,各含量普遍高于50%和70%湿度环境中的红提葡萄,品质保存最好。结论2℃温度及90%湿度的低温高湿环境最适宜采后浆果的贮藏,在相同贮藏期内红提葡萄的腐烂率最低,同时其风味品质、质构品质和货架品质能得到较好的保持,保鲜效果显著。     

溶菌酶在草莓涂膜保鲜中的应用研究

研究溶菌酶、壳聚糖、氯化钙对草莓的涂膜保鲜效果。采用不同浓度溶菌酶跟壳聚糖和氯化钙复配保鲜液对草莓进行保鲜处理,贮于4℃。研究结果表明,0.05%溶菌酶、1%壳聚糖和0.5%氯化钙复配保鲜液对草莓保鲜效果最佳。该组草莓在贮藏前9天内,草莓无烂果出现,草莓的色泽、风味、硬度均保持良好,贮藏第9天草莓烂果率为0,失重率为3.12%,VC含量为77.7 mg/100g,仅下降9.44%,还原糖含量为5.42 g/100g,仅下降15.7%,总酸含量为7.63 g/kg,仅下降39.4%。溶菌酶涂膜保鲜技术能有效延长草莓的货架期,较好保持其感官和营养品质。     

芦荟提取物对葡萄保鲜及贮藏品质的影响

研究了不同浓度芦荟提取物对葡萄的保鲜作用及贮藏品质的影响.结果表明,芦荟提取物处理葡萄果穗后可有效降低葡萄腐烂率、脱粒率及果梗褐变指数,延缓可溶性固形物、有机酸及Vc的降解,较好地维持葡萄贮藏品质,其中50％浓度的芦荟叶表皮与叶肉混合提取物保鲜作用最佳.     

3种天然保鲜剂对凤尾菇的保鲜效果

目的:研究肉桂精油、壳聚糖和抗坏血酸3种天然保鲜剂对凤尾菇储藏过程中的保鲜效果。方法:以新鲜凤尾菇为研究对象,分别采用不同浓度肉桂精油、壳聚糖和抗坏血酸对凤尾菇进行处理,结合感官评价找出3种保鲜液的最佳浓度,并研究不同浓度保鲜剂的凤尾菇在5 ℃贮藏过程中感官评价、呼吸强度、褐变度和腐烂指数的变化规律。接着通过正交试验,以3种不同浓度的保鲜剂为考察因素,感官评价与失重率为指标,选出保鲜效果最佳的复合保鲜剂配方。结果:单一涂膜处理时,肉桂精油1.5 g/L、壳聚糖15 g/L和抗坏血酸1.0 g/L具有最好的保鲜效果。最佳的复合保鲜剂配方为,肉桂精油浓度为1.0 g/L、壳聚糖浓度为15 g/L和抗坏血酸浓度为1.0 g/L,该复合保鲜液处理凤尾菇贮藏9 d,感官评分为(78±3)分,失重率为6.98%±0.43%。结论:此复合保鲜液对凤尾菇的保鲜能起到更明显的效果,贮藏期间凤尾菇的品质和色泽均较好。     

生姜-壳聚糖保鲜液对马铃薯净菜贮藏品质的影响

本文以马铃薯为原料,通过无菌水、0.1%生姜提取液、0.1%生姜-壳聚糖保鲜液、0.5%生姜-壳聚糖保鲜液四种不同浸泡方式,测定马铃薯净菜在贮藏期内Vc含量、失重率、多酚氧化酶活性、菌落总数、感官品质。结果表明：生姜提取液对马铃薯净菜有一定的保鲜效果,生姜-壳聚糖保鲜液保鲜效果更好。0.5%生姜-壳聚糖保鲜液可以有效减缓马铃薯净菜Vc的损耗,降低失重率,抑制PPO酶活性和微生物的生长繁殖,保持马铃薯净菜的感官品质;贮藏第7d时,Vc含量、失重率、PPO酶活性、菌落总数和感官评分分别为24.61mg/100g、0.97%、2.61U/g、2.14 lg CFU/g、16.19分。     

1-MCP对木纳格葡萄的保鲜效果

为寻找新型、无硫的鲜食葡萄保鲜方法,以新疆木纳格葡萄为试材,研究0.5、1.0和1.5 μL/L的1-MCP熏蒸处理对其在常温(25±0.5) ℃和冷藏(0~3) ℃贮藏期间果实的主要品质、生理指标及其作用效果的影响。结果表明:1-MCP熏蒸处理能在不同程度上降低常温贮藏条件下以及冷藏条件下葡萄的脱粒率、腐烂率、果穗失重率和果梗褐变,保持葡萄的硬度、可溶性固形物、V_C含量、可溶性糖含量以及可滴定酸含量。室温贮藏结束时,1.0 μL/L浓度1-MCP处理的葡萄可溶性糖含量为10.18%,比对照组高出29.36%,可溶性固形物比对照组高出20.65%,而失重率却比对照组低34.85%。冷藏贮藏结束时,1.0 μL/L浓度1-MCP处理的葡萄腐烂率为26.13%,比对照组低30.49%,而V_C含量比对照组高出34.38%。0.5 μL/L和1.5 μL/L的1-MCP处理对维持果实品质也有一定的作用,但是效果均不如1.0 μL/L处理的果实明显。综上所述,1.0 μL/L浓度的1-MCP处理的葡萄腐烂率最低,果实的外在品质和内在品质下降幅度最小,保鲜效果最好。     

SO 2 结合壳聚糖处理对采后鲜食葡萄品质的影响

以巨峰葡萄(Kyoho)为试验材料,分别以蒸馏水、各浓度壳聚糖溶液(0.5%、1.0%、1.5%)、二氧化硫(SO_2)保鲜剂、SO_2保鲜剂与各浓度壳聚糖溶液(0.5%、1.0%、1.5%)共同处理,后置于0℃环境下贮藏,通过对贮藏过程中果实各项生理指标的检测和分析,研究了壳聚糖降低SO_2对葡萄的伤害程度。结果表明:壳聚糖处理能够减少SO_2对失重率、落粒率、硬度等方面所带来的伤害。故壳聚糖对于巨峰葡萄的采后贮藏品质有着较好的控制,是一种具有广阔市场前景的葡萄保鲜剂。     

连翘精油对小白菜保鲜效果的影响

以"鸡毛"小白菜品种为实验材料,采用不同浓度(0.1%、0.5%、1.5%、3%)的连翘精油保鲜液对小白菜进行处理,研究了连翘精油在小白菜贮藏过程中的保鲜效果。结果表明,0.5%连翘精油保鲜液处理大大降低了小白菜的失重率、叶绿素含量和Vc含量的损失率,有效地保持了感官品质。并且,在此浓度下,通过3种施加方式(喷洒、涂抹和熏蒸)处理小白菜,发现熏蒸能更充分地发挥连翘精油的抑菌保鲜作用,可以延缓小白菜贮藏品质的下降,提高小白菜的货架寿命。     

提高双歧杆菌在离心过程中活菌收得率的研究

菌体细胞的分离技术是制备双歧杆菌冻干制剂重要的中间工艺环节。本文建立了研究离心过程国活菌收得率与损失率、存活率相关性试验方法。选择改良ＭＲＳ培养基为离心基质研究了离心力、离心时间、基质ＰＨ对两歧双歧杆菌（Ｂ．ｂｉｆｉｄｕｍ）离心损失率和存活率的影响,确定了活菌收得率最高的适宜离心条件。结果表明：增大离心力和延长离心时间,离心损失率和存活率均显著降低（Ｐ〈０．０１）;影响离心存活率的阈值为４２９７ｇ     

不同类型甜菜品种叶部光合性状与产质量关系的研究

研究了不同类型甜菜品种叶都光合性状与产质量的关系，结果表明，在不同生育时期ＲｕＢＰ羧化酶活性在品种之间存在的显著差异，可将其作为前期和糖分积累期选育高糖型品种的生理指标，并可在块根增长期作为选育丰产型品种的生理指标，在苗期与块根增长期，光合速率与块根产量呈极显著正相关，在整个生育期间单株叶面积均与产量呈正相关，因此可将单株叶面积，光合速率和分配率一并并作为丰产型品种的选育指标。     

化学浆几种蒸煮方法的特点及机理

本文综述硫酸盐法、烧碱法、碱性亚钠法、中性亚钠和亚铵法蒸煮过程脱木素及碳水化合物溶出的特点,根据各种蒸煮液与木素和碳水化合物的反应性能及机理,阐明几种蒸煮方法的脱木素历程和碳水化合物溶出规律存在区别的原因。     

超声波对皮革染色的影响

研究了不同频率超声波作用于酸性黑ATT后对其染色性能的影响,并着重研究了超声波的作用时间、染色温度等对染料上染速率及上染百分率的影响规律.结果表明频率为23.7kHz的超声波对皮革染色有促染作用,而17kHz的超声波则没有;染料溶液经超声波预处理20-30min,再在较低温度(45℃)下染色,可加快上染速率,提高上染百分率至99.24%-99.75%,降低废液中染料的含量,减少污染.     

自动包装机生产率的分析

介绍了自动包装机的理论生产率和实际生产率计算公式，分析了影响生产率提高的主要因素。     

两种温度下斯里兰卡橄榄贮藏特性的比较研究

探讨了斯里兰卡橄榄在常温和低温下的贮藏效果。分别在室温(25oC)和低温(9℃±1)贮藏。跟踪测定果实的呼吸强度、电导率、过氧化物酶活性、维生素C含量的变化和腐烂率、失水率。结果表明斯里兰卡橄榄属典型呼吸高峰型果实,低温可有效降低呼吸强度和延迟呼吸高峰的出现;两种温度下的电导率和过氧化物酶活性均随贮藏时间的延长而变大,但在低温条件下变化速度较慢;低温条件下维生素C的损失较小;两种温度下失水率均较低,表明蒸腾作用较弱;低温条件下的腐烂率远低于常温贮藏条件下。低温可明显改善斯里兰卡橄榄的贮藏性,延长斯里兰卡橄榄的贮藏寿命。     

Reproductive status of Holstein and Jersey cows in the United States

Reproductive information since 1995 from the USDA national dairy database was used to calculate yearly Holstein and Jersey means for days to first breeding after calving (DFB), 70-d nonreturn rate, conception rate (CR), number of breedings per lactation (NB), interval between first and last breedings during the lactation, days to last breeding after calving (DLB), pregnancy rate (PR), calving interval (CI), and interval between consecutive breedings. Data were from nearly 20 million breedings during >8 million lactations of >5 million cows in >23,000 herds. Means were also calculated for some traits by parity and breeding number for both breeds and by geographical region and synchronization status for Holsteins. The DFB declined for Holsteins from 92 d in 1996 to 85 d in 2007; the trend in yearly differences was not as consistent for Jerseys. First- and all-breeding 70-d nonreturn rate declined 5 to 9 percentage units over time. First- and all-breeding CR declined 2 to 4 percentage units. The DFB were longer for later parities of Holsteins than for early parities. Second- and third-breeding CR were sometimes 1 to 2 percentage units above first-breeding CR for Holsteins but lower (1 to 7 percentage units) for Jerseys. The CR within breeding number declined across parities for both breeds. The NB increased by 0.3 to 0.4 breedings over time but remained constant (2.5 or 2.6 breedings) across parities for Holsteins and increased (from 2.2 to 2.4 breedings) for Jerseys. Holstein DFB were fewest in the Northwest (78 d) and greatest in the Mountain region (92 d). Regional CR was highest for the Northeast and Southwest (33%) and lowest for the Southeast (26%); NB was fewest for the Northeast (2.3) and greatest for the Southeast (2.7). Mean DLB was fewest for the Southwest (127 d) and greatest for the Mountain region (157 d); CI was shortest for the Southwest (406 d) and longest for the Mideast (434 d). Mean PR was highest for the Southwest (28.3%) and lowest for the Mideast and Southeast (22.2%). Use of timed artificial insemination following synchronized estrus appears to have reduced DFB, lowered CR, and increased NB while reducing DLB and CI. However, synchronized breeding was not a primary cause of Holstein regional differences for reproductive traits. Since 2002, phenotypic performance for CR, DLB, and CI as well as genetic merit for daughter PR have stopped their historical declines and started to improve.     

乙醇清除亚硝酸根及抑制N-亚硝基二乙胺形成的体外研究

在模拟人体胃液条件下,研究了乙醇清除亚硝酸根和抑制N-亚硝基二乙胺(NDEA)形成的能力。分别用盐酸萘乙二胺法和反相高效液相色谱法(RP-HPLC)测定亚硝酸根和NDEA的量。结果显示:当pH为2.0～4.5时,乙醇既能清除亚硝酸根又能抑制NDEA的形成;pH为5.0时,乙醇对亚硝酸根有清除作用,对NDEA的形成却有促进作用。在pH为3.0,37℃条件下,乙醇的清除及抑制效果与反应时间及乙醇的浓度呈正相关。在模拟胃液条件下,乙醇对亚硝酸根的致癌活性具有较好的抑制作用。     

Effects of corn grain endosperm type and fineness of grind on site of digestion,ruminal digestion kinetics,and flow of nitrogen fractions to the duodenum in lactating dairy cows

Our objective was to evaluate effects of corn grain endosperm type and fineness of grind on feed intake, feeding behavior, and productive performance of lactating cows. Eight ruminally and duodenally cannulated Holstein cows in mid lactation (130 ± 42 d in milk; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design with 21-d periods. A 2 × 2 factorial arrangement of treatments was used with main effects of corn grain endosperm type (floury or vitreous) and fineness of grind (fine or medium). Rations included alfalfa silage, corn treatments, protein supplement, minerals, and vitamins and were formulated to contain 29% starch, 27% neutral detergent fiber, 18.2% forage neutral detergent fiber, and 18% crude protein. Corn grain treatments supplied 86.2% of dietary starch. Endosperm was 25% vitreous for the floury treatment and 66% vitreous for the vitreous treatment. The floury treatment increased rate of starch degradation by 94% (19.2 vs. 9.9%/h) and decreased rate of starch passage by 38% (16.1 vs. 25.8%/h), increasing apparent ruminal starch digestibility by 117% (53.7 vs. 24.7%). The floury treatment increased total-tract starch digestibility by 8% (92.2 vs. 85.1%) despite 37% lower postruminal starch digestion for the floury treatment compared with vitreous corn (38.4 vs. 60.7% of starch intake). Fine grind size increased apparent ruminal starch digestibility by 52% (47.2 vs. 31.1%) compared with medium grind size by increasing the rate of starch degradation by 105% (19.5 vs. 9.5%/h) with no effect on rate of starch passage. However, total-tract starch digestibility was not affected by fineness of grind because postruminal starch digestibility was 37% greater for medium compared with fine grind size (57.2 vs. 41.9% of starch intake). Endosperm type did not affect flow of nitrogen (N) fractions to the duodenum or microbial N efficiency, whereas fine grind size increased duodenal flow of nonammonia N by increasing duodenal flow of microbial N by 22% compared with medium grind size (438 vs. 359 g/d) but did not affect apparent total-tract N digestibility. No interactions were detected for any measure of starch digestion, ruminal N metabolism, or flow of N fractions to the duodenum. Endosperm type greatly affected ruminal and total-tract starch digestibility independent of the fineness of grind of corn grain with no effects on flow of N fractions.     

中国肥胖流行的现状与趋势

以中国家庭营养与健康调查（CHNS）数据库为基础,统计分析了我国从1989--2009年20年间成人超重率及肥胖率的变化趋势。分析结果表明,从1989--2009年的20年,是肥胖蔓延的20年,我国成人肥胖率呈迅速增长的态势,严峻的肥胖流行趋势和严重的肥胖流行后果将会成为我国未来无法承受的社会负担。这提醒我们应防胖于未然,采取必要的公共政策来防止肥胖流行。