温度和包装对巨峰葡萄贮藏品质的影响

研究了不同贮藏温度(常温、8℃和0℃)和包装(30μm和50μmPE膜)条件下巨峰葡萄果实失重率、Vc、TSS和可滴定酸含量变化情况。结果表明,随着贮期的延长,果实失重率增加,Vc和可滴定酸含量逐渐减少,TSS含量先上升后降低。低温和包装能够显著抑制果实水分蒸发,保持TSS和可滴定酸含量的相对稳定;低温保持了较高的VC含量,但包装效果不明显。30μm PE包装较50μm对葡萄贮藏效果好。     

不同包装对冷藏和货架期黑布朗李果实品质及乙烯释放速率的影响

黑布朗李分别经PE、PVC和微孔膜包装后在0℃贮藏,以无包装为对照,研究不同材料包装对冷藏及货架期(25℃)黑布朗李果实品质的影响。结果表明,包装可以显著(p0.05)降低果实失重率,对果实贮藏期品质具有良好的影响;PVC包装能显著地降低包装内O_2体积分数(p0.05),提高CO_2体积分数,并能够有效地延缓货架期李果实硬度下降,维持较高的SSC;PE包装的李果实软化缓慢,与其他组果实相比转色指数最高。PE、PVC和微孔膜包装均能有效地抑制贮藏过程中李果实乙烯的释放速率。     

水气耦合对青皮核桃贮期腐烂的控制与品质保持的效应

为了探究适当失水与自发气调包装对青皮核桃保鲜的协同效应,本文以‘西扶2号’核桃鲜果为试材,采取0、5%、10%3种果实失重率与PE30、PE50两种自发气调包装(水气耦合)条件复合处理,以0失水加食品保鲜膜包装为对照,(0±0.5)℃下贮藏。结果发现,各处理对果实的保鲜效果和核桃仁品质保持能力均高于对照,以失水10%复合PE50包装处理(10%+PE50)最强,5%+PE30其次。贮藏80 d后10%+PE50的裂果率、腐烂率、褐变指数最低,分别为:2.1%、2.0%、10%,对照分别为:81.6%、42.4%、80.0%;10%+PE50的核桃仁总酚、类黄酮含量、总抗氧化能力最高,均显著高于对照(p0.05),核桃仁感观品质下降最少,核桃仁的丙二醛(MDA)、过氧化氢含量、酸价、过氧化值最小。贮藏110 d后,10%+PE50的果实腐烂率11%,因褐变指数大于20%,贮藏中止。因此,失水10%复合PE50包装处理被选为最有效的水气耦合条件,能使青皮核桃保鲜期延长至110 d。     

包装与温度对欧芹贮藏效果的影响

研究了不同贮藏温度(常温、0℃)和包装(20μm、30μm和60μmPE膜)条件下欧芹枝叶Vc、叶绿素和类胡萝卜素含量以及失重率、含水量变化情况。结果表明:随着贮期的延长,欧芹失重率增加,Vc、叶绿素和类胡萝卜素含量逐渐减少。低温和包装能够显著抑制水分蒸发,保持较高的Vc、叶绿素和类胡萝卜素含量,30μmPE包装较20μm和60μm贮藏效果好。     

不同温度、1-MCP浓度和薄膜包装对青脆李耐贮性的影响

比较了不同温度(4、10℃和常温)、不同浓度1-MCP(0.5μL/L、0.75μL/L和1.0μL/L)和不同薄膜(PE膜、PVC膜、微孔薄膜)包装青脆李贮藏期间果实品质的变化。结果表明:4℃条件下青脆李果实贮藏期从常温下的3-5d延长至16d左右,延长贮藏时间约10d,其中好果率大于90%,并有效保持青脆李果实硬度,抑制SSC、TA、可溶性糖含量的降低;0.75μL/L 1-MCP处理后的青脆李于4℃条件下贮藏期可达到25d,好果率大于90%,有利于抑制果实硬度和SSC含量的下降,有效维持青脆李果实糖酸含量;PE膜包装有利于抑制果实硬度、SSC的下降,微孔膜有利于抑制TA含量的下降,PVC膜能保持果实较高可溶性糖含量。4℃、0.75μL/L 1-MCP和薄膜包装分别为最适合于青脆李贮藏保鲜的单因素条件。     

不同MA包装对鲜食核桃冷藏品质的影响

为筛选鲜食核桃冷藏期间适宜自发气调(modified atmosphere,MA)包装,以‘辽核2号’鲜食核桃为试材,采用改良聚乙烯袋-11μm(Thn-PE 11)、聚乙烯袋-30μm(PE 30)、聚乙烯袋-50μm(PE 50)和改良聚乙烯袋-90μm(Thk-PE 90)4种不同的MA包装处理,以6μm普通聚乙烯薄膜包装为对照,贮藏于(0±1)℃条件下,定期检测其感官品质、失重率、好果率、CO_2和O_2体积分数以及脂肪、蛋白质、可溶性蛋白、过氧化值(PV)、羰基价(CV)等指标的变化。结果表明,MA包装能够显著提高鲜核桃感官品质和保水能力,其中PE 30包装鲜食核桃品质指标综合表现较好,确定PE 30为鲜食核桃冷藏适宜MA包装。     

低温结合薄膜包装对石榴果实采后生理及贮藏品质的影响

以陕西临潼"净皮甜"石榴为原料,研究石榴果实经低温结合薄膜包装处理后采后生理和贮藏品质的变化,为后续石榴贮藏保鲜提供技术参考。石榴经预冷后,用厚度0. 01 mm的聚乙烯(polyethylene,PE)塑料保鲜膜单果覆膜包装,分别置于(0±0. 5)℃、(4±0. 5)℃和(8±0. 5)℃、相对湿度90%～95%的冷库中贮藏。以未经薄膜包装处理贮藏的石榴作对照,贮藏期间每隔30 d随机取样测定果实可溶性固形物含量、可滴定酸含量、V_C含量、呼吸速率、相对电导率、褐变指数、失重率、腐烂率,并进行感官评价。结果表明,石榴采用厚度为0. 01 mm聚乙烯薄膜包装,在温度(4±0. 5)℃条件下贮藏,能有效地保持果实的可溶性固形物含量、可滴定酸含量和V_C含量,抑制果实呼吸作用,减缓果皮相对电导率和褐变指数升高,降低果实失重率和腐烂率。贮藏120 d时果实外观色泽鲜艳,籽粒感官品质良好,保鲜效果理想。(4±0. 5)℃下经0. 01 mm聚乙烯薄膜包装可以有效延长石榴贮藏期。     

钙和热预处理对草莓保鲜的生理效应

研究了热处理结合浸钙处理分别对包装和不包装的半红期草莓的贮藏保鲜效果,结果表明:45℃ 1?Cl2溶液浸泡草莓20min后,以30μm PE保鲜膜包装贮藏,可以提高草莓果实的钙含量,保持较高的原果胶含量和硬度,抑制花青苷的形成,有效地延缓果实成熟衰老,达到最佳的保鲜效果.     

包装材料和贮藏温度对辣椒冷藏货架期品质变化的影响

为探究包装材料和贮藏温度对辣椒品质及冷藏货架期的影响,采用不同包装材料(PE、OPP和TS复合材料)对辣椒进行包装,在不同贮藏温度(2℃、5℃和9℃)下对新鲜辣椒保鲜贮藏,并采用一定方式测定不同贮藏时间下辣椒的质量损失率、腐烂率、转红率、冷害率和风干率。结果表明:采用PE保鲜袋并在9℃时对辣椒进行保鲜贮藏,可明显抑制辣椒在贮藏过程中的腐烂、冷害和风干现象,对辣椒贮藏过程中的感官品质的保持较有利。     

青皮鲜核桃低温贮藏后货架期品质的变化

以青皮鲜核桃为试材,研究不同厚度PE包装的青皮鲜核桃结合低温贮藏60d后,转入常温货架期间果实品质及生理的影响。结果表明:在货架期间,经厚度为40、50μm的PE袋包装处理过的青皮鲜核桃能有效地保持其原有水分和色泽,降低呼吸强度,提高青皮鲜核桃仁过氧化物酶(POD)和过氧化氢酶(CAT)的活性,并使脂氧合酶(LOX)活性维持在较低的水平,能够有效保持青皮鲜核桃的品质,延缓果实衰老。与对照组相比,经厚度为40μm的PE袋包装处理过的青皮鲜核桃货架期延长到9d,保鲜效果良好。     

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.     

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。     

用3M测试片检测食品加工环境李斯特菌

共采集112个环境样本,挑取了210个典型菌落,70个非典型菌落进行鉴定,评估3M测试片对食品加工环境中李斯特菌的检测能力。结果为3M测试片检测李斯特菌的阳性符合率为97·6%,阴性符合率为100%。这些结果表明3M测试片用于食品加工环境李斯特菌的快速检测不失为一种好方法。     

利用酶法促使骨粉中钙转化的研究

利用中性蛋白酶,胰酶和碱性蛋白酶作用于骨粉,胰酶可获得最大钙转化率。研究表明,骨粉中钙溶出率为２．５６％,骨钙转化率为１６．０％,并且确定胰酶最佳用量为骨粉：胰酶（ｗ／ｗ）＝１０００：１－２０００：１,最佳酶解时间为９－１０ｈ。     

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

Our objective was to evaluate the relative effects of endosperm type and conservation method of corn grain on ruminal kinetics, site of nutrient digestion, and flow of nitrogen fractions to the duodenum in lactating dairy cows. Seven ruminally and duodenally cannulated Holstein cows (73 ± 39 d in milk; mean ± SD) 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 conserved as dry ground corn (DGC) or high-moisture corn (HMC). Rations were formulated to contain 27.0% starch, 26.6% neutral detergent fiber (NDF), 19.1% forage NDF, and 16.5% crude protein. Corn grain treatments supplied 86.6% of dietary starch, and alfalfa silage was the sole forage. True ruminal starch digestibility was increased by HMC compared with DGC (87.2 vs. 64.3%) and by floury compared with vitreous corn grain (83.7 vs. 67.7%). The increase for HMC compared with DGC was because of an increase in the degradation rate (33.8 vs. 23.1%/h) and a decrease in passage rate of starch (7.6 vs. 15.2%/h). The increase for floury compared with vitreous corn grain was because of an increase in the degradation rate (31.5 vs. 25.4%/h) and a decrease in rate of starch passage from the rumen (7.9 vs. 14.9%/h). Apparent total-tract starch digestibility was increased by HMC compared with DGC and by floury compared with vitreous corn, but the increase for floury corn was greater for the DGC treatment. Dry ground corn compared with HMC tended to increase nonammonia N flow to the duodenum (466 vs. 431 g/d) by increasing flow of nonammonia nonmicrobial N (211 vs. 111 g/d) despite a decrease in microbial N flow (255 vs. 320 g/d). Vitreous corn increased nonammonia nonmicrobial N flow to the duodenum (187 vs. 135 g/d) compared with floury corn, but microbial N flow to the duodenum was not affected by endosperm type. Efficiency of microbial N production was not affected by treatment. Endosperm type and conservation method of corn grain greatly affect digestion kinetics and ruminal digestibility of starch as well as flow of N fractions to the duodenum and should be considered during diet formulation for lactating cows.     

纤维素酶催化大豆异黄酮的水解

为充分发挥大豆异黄酮生物价值,采用纤维素酶催化糖苷型大豆异黄酮水解制备游离苷元型大豆异黄酮。通过考察10种纤维素酶对糖苷型大豆异黄酮总水解率和苷元型大豆异黄酮总转化率的影响,筛选得到一种成本较低且水解效果较好的纤维素酶,用于催化水解糖苷型大豆异黄酮,优化了该纤维素酶在水解工艺中底物质量浓度、酶添加量、反应体系pH、酶解温度、酶解时间等参数。结果表明：选择来源于Trichoderma viride的纤维素酶作为大豆异黄酮水解用酶;底物质量浓度0.8～2.0 mg/mL、酶添加量7%～11%、反应体系pH 5.0、酶解温度55℃、酶解时间5～6 h是较经济有效的水解工艺参数,实验优化过程中,大豆异黄酮总水解率超过90%,总转化率接近60%。因此,采用纤维素酶催化水解大豆异黄酮可显著增加游离苷元含量,提高大豆异黄酮利用价值。     

复合变性淀粉提高鸡胸肉保水率的研究

报道了利用复合变性淀粉提高鸡胸肉保水率的研究。通过单因素实验，分别研究了磷酸酯玉米淀粉、磷酸酯木薯淀粉、交联马铃薯淀粉、交联木薯淀粉、醋酸酯玉米淀粉添加量对胸肉的吸水率和失水率的影响。根据单因素实验结果，进行了正交实验，验证得出最优配方为磷酸酯玉米淀粉为0．4％，磷酸酯木薯淀粉为0．8％，交联马铃薯淀粉为0．5％，交联木薯淀粉为0．6％及醋酸酯玉米淀粉为0．06％。经过验证实验所得到的吸水率和失水率的数据分别为7．9％和13．8％。     

无磷酸盐制剂对牛肉嫩度和保水性的影响

研究一种新的制剂替代磷酸盐达到对牛肉保水嫩化的效果。通过L9(34)正交实验确定了制剂的最佳配比为苹果酸钠4%、醋酸钠1.5%、氯化钠1.5%、水93%。结果表明,此制剂具有较好的保水效果及嫩化能力,使牛肉的蒸煮损失率降低至14.79%(P<0.05),剪切力减少到22.90N(P<0.05)。     

不同粒度小麦粉的实验筛理性能探讨

通过对制粉生产中不同制粉系统小麦粉的筛理试验,探讨不同粒度小麦粉的筛理性能。结果表明:粉筛筛网的加密导致小麦粉筛出率的递减,但不同系统递减的幅度不同,心磨系统递减的幅度较大,渣磨及尾磨相对较小。小麦粉的筛净率主要为筛理时间的函数,与小麦粉的粒度呈负相关,而与筛理物料含粉率的关系相对较小。     

荞麦通心粉生产工艺探讨

本文以甜荞(Fagopyrum csculentum)和苦荞(F.tartaricum)面粉为原料,以小麦(Triticum aestivum)面粉和商品通心粉(spaghetti)为对照,测定了荞麦面粉的淀粉特性,探讨了荞麦粉的加工工艺参数和荞麦与小麦面粉的配粉比例,分析评价了加工成品在煮熟过程中的干物质损失率、蛋白质损失率,为大规模工业化生产荞麦通心粉提供理论依据。