冷却和冷冻对猪背最长肌动态黏弹性和凝胶特性的影响

研究猪背最长肌在热鲜、冷却、冷冻这3种不同处理条件下的pH值、蛋白溶解度、动态黏弹性和凝胶特性(凝胶保水性(WHC)、凝胶强度、凝胶弹性),并比较其差异。结果显示:热鲜肉的pH值和蛋白溶解度均最高,并且具有较好的动态黏弹性和凝胶特性;冷却肉的pH值和蛋白溶解度相对较低,其凝胶特性和动态黏弹性均不如热鲜肉好;冷冻肉的pH值和蛋白溶解度最低,凝胶保水性和动态黏弹性最差,其凝胶强度和凝胶弹性低于热鲜肉却高于冷却肉。说明冷藏处理过程损坏了肉品的功能特性,因此热鲜肉的功能特性相对最佳。     

Muscle Properties of Physically Restrained Stressor-Susceptible and Stressor-Resistant Porcine Animals

SUMMARY— Studies of the effects of duration of physical restraint of porcine animals revealed breed influences on the responses occurring in muscles. The rate and extent of glycolysis and the color and gross morphology of the muscles of Poland China animals became more severely affected as the duration of restraint increased. The muscles of Chester White animals, however, responded to the stressor initially but, with prolonged restraint, returned to glycolytic and morphological states resembling those of unrestrained animals. The results emphasize the importance of genetic influences on stress responses and resultant muscle morphology and indicate that a specific treatment may ultimately produce opposite effects in animals that differ in susceptibility to stressors.     

高温、高湿干燥工艺对挂面产品特性的影响

为明确高温、高湿干燥工艺参数(80℃,85%)对挂面产品特性的影响,改进挂面干燥工艺,保障产品质量。以小麦品种永良4号为原料,在实验室制作挂面;干燥试验采用两因素三水平(温度:40,60,80℃;相对湿度:65%,75%,85%)全排列组合设计,干燥时间300 min;测定干挂面色泽、密度、收缩率和抗弯曲特性等。结果表明,干燥温度对产品最终水分含量影响较大,对挂面色泽b*值和密度有极显著影响,对收缩率、折断距离和折断功有显著影响,对色泽L*值、a*值和抗弯强度没有影响。相对湿度对挂面色泽L*值、a*值、b*值、密度和抗弯曲特性均有显著或极显著影响。温度和相对湿度互作对色泽b*值、抗弯曲特性有极显著影响。干燥过程中相对湿度对挂面产品质量影响较大。与常规干燥工艺(40℃,75%)相比,挂面经高温、高湿(80℃,85%)干燥后,挂面色泽b*值、抗弯强度、折断距离、折断功均显著升高,L*值、a*值、密度、收缩率没有显著变化。本研究结果表明:高温、高湿工艺应和干燥设备设计、热能损失、能耗分析及产品特性评价相结合。     

Relationship of Color with Certain Chemical and Physical Properties of Porcine Muscle

SUMMARY— The dominant wavelength of muscle color depended almost exclusively on pH. A high pH was associated with a high dominant wavelength. Muscle color saturation was associated with moisture content, pH, water-holding capacity, and myoglobin content. The color exhibited the highest degree of purity in muscles that were high in myoglobin content and low in pH, water-holding capacity, and water content. Color lightness was negatively associated with pH, water-holding capacity, and muscle pigments.     

贮藏温度和湿度对鸡腿蘑保鲜效果的影响

研究了鸡腿蘑在0、5、10、15、20℃5种温度条件和RH为50%~60%、90%~95%2种湿度条件下的贮藏试验。结果表明,低温可明显抑制鸡腿蘑的呼吸强度、失重率、和褐变率;高湿可显著减少鸡腿蘑采后的失重率,但会使褐变率增加。鸡腿蘑采后的贮藏温度推荐为0~5℃,RH为90%~95%,在此条件下的贮藏期限为2周。     

温度、湿度条件对蜂王浆贮藏影响的研究

本文研究了不同温度、湿度条件对蜂王浆贮藏的影响。蜂王浆的考察指标为水溶性蛋白质、维生素C、色差及主要感官变化。结果表明,在低温、低湿条件下贮藏蜂王浆,可以有效保留其活性成分。     

温度和相对湿度对采后葡萄浆果硬度的影响

本文研究温度和相对湿度对采后葡萄浆果硬度的影响,并建立了相应的预测模型。以酶反应动力学为基础了建立葡萄浆果硬度变化的基础模型,并进一步引入温度、相对湿度和水蒸汽压差对硬度的影响,对基础模型进行了修正,结果表明模型的预测值和实验测量值间吻合良好(R2=0.93601,E=4.72%)。     

Effect of Heating Temperature and Muscle Type on Porcine Muscle Extracts as Determined by Reverse Phase High Performance Liquid Chromatography

Samples from porcine longissimus muscles were heated to temperatures ranging from 40–80°C to reach endpoint temperatures (0 min) or held at endpoint temperature for 30 min. Proteins in water-soluble extracts of these samples were separated and quantified by reverse phase high performance liquid chromatography (RP-HPLC). After heating to 60°C for 0 min or to 55°C and holding for 30 min, lactate dehydrogenase (LDH), pyruvate kinase (PK) and myoglobin appeared to comprise the bulk of the remaining soluble protein. RP-HPLC analysis of water soluble extracts from longissimus dorsi, serratus ventralis and psoas major muscles from barrows and sows indicated differences in proportions of LDH and myoglobin.     

烘烤过程中温湿度对烤烟淀粉酶活性的影响

研究了烘烤过程中温湿度对烤烟淀粉酶活性的影响。结果表明:①烘烤过程中,鲜烟状态下烟叶淀粉酶的活性变化呈双峰曲线,36℃时出现一个峰值,此时鲜烟的淀粉酶活性最高,38℃出现另一个高峰。凋萎状态下38℃时淀粉酶活性最高。小卷筒状态下,在37~40℃范围内,烟叶淀粉酶的活性随温度升高而增加;②在干球温度38℃条件下,干湿差3℃(相对湿度79%)至1.5℃(相对湿度89%)范围内,鲜烟叶保持较高的淀粉酶活性,之后随着干湿差的减小,鲜烟叶淀粉酶活性迅速降低。在干球温度40℃条件下,干湿差3℃(相对湿度80%)至2℃(相对湿度86%)范围内,凋萎烟叶淀粉酶活性较高,干湿差小于1.5℃时,凋萎烟叶的淀粉酶活性有所降低。小卷筒状态下,烟叶淀粉酶活性随相对湿度的增大而逐渐升高。     

加热温度对猪肉肌原纤维蛋白凝胶特性的影响

本实验研究在不同温度(50～90℃)条件下加热对猪肉肌原纤维蛋白凝胶特性的影响。结果显示：温度为70、80℃制备的凝胶保水性较好;50℃和60℃形成的凝胶颜色较深;70～90℃形成凝胶的白度基本相同,无显著差异(P＞0.05);凝胶硬度和咀嚼性随温度的升高先升高后降低,在温度为70～80℃时达最大值;浊度随着温度的升高而总体呈升高趋势,但达到70℃以上时,升高趋势变缓。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)研究发现,在45～65kD之间,在温度升高到70℃以上时,逐渐出现了明显的条带,表明部分蛋白发生了分解。表明肌原纤维蛋白在70～80℃所制得凝胶产品的功能特性较好。     

湿空气特性对烟片松散回潮过程的影响

采用析因试验方法,通过设备参数、湿空气特性和加工质量的相关分析,研究了湿空气特性对叶片松散回潮过程的影响,探讨了稳定提高烟片松散回潮质量的控制方法.结果表明:[1]湿空气的温湿度对松散回潮后烟叶的温度、含水率、松散效果和感官质量均有显著影响,并显著影响松散回潮后烟叶温度的稳定性;[2]采用以入口湿空气温湿度为主要控制因素的控制方法,可以缩短控制响应时间,有效消除多点加工过程中由于机型、设备不同所造成实际加工条件的差异,同时也有利于针对原料质量特点的不同采用相应的加工条件.     

温、湿度对储藏小麦粉中霉菌区系的影响

通过模拟储藏,研究了温、湿度对小麦粉储藏过程中霉菌区系的影响。结果表明,小麦粉储藏一段时间后水分达到平衡状态,且水分与储藏温度和湿度呈显著的二元线性关系。由于储藏温度和小麦粉水分的联合影响,随着储藏时间的延长,霉菌量基本呈下降趋势,通过方差分析,在大多数情况下,温度是影响小麦粉中霉菌量的显著性因素,特别在55%湿度下,霉菌量与温度、储藏时间呈显著的二元非线性关系。在储藏温度≥20℃条件下,湿度是影响小麦粉中霉菌量的显著性因素。另外在不同温、湿度条件下,优势菌始终是白曲霉,但比例略有差异。     

Calcium and Time Postmortem Effects on Functional and Textural Characteristics of Porcine Semimembranosus Muscle

Muscle samples removed immediately postexsanguination were vacuum marinated in CaCl₂, EGTA, and NaCl and chemical and textural analysis was performed at 0, 3, 6, and 24 hr postmortem. Samples at 0 hr were tougher within respective treatments than those stored 24 hr. Marination increased moisture absorption, and consequently, purge and cooking losses as well. Calcium marination resulted in faster pH declines and more rapid ATP depletion. No significant effects on color or shear force values were observed for any treatments.     

Cooking Temperature, Bird Type, and Muscle Origin Effects on Sensory Properties of Broiled Emu Steaks

Trained sensory panel scores and Warner-Bratzler shear values (WBS) of emu meat cooked to three end-point temperatures (60, 66, and 75°C), obtained from two bird types (breeder quality, BQ; and nonbreeder quality, NBQ), and from five carcass locations were determined and compared in three studies. NBQ birds had obvious conformational defects. Full rumps and inside drums broiled to 60°C were more tender and juicy than those broiled to 66 or 75°C (P<0.05). Cooking temperature did not affect meat-flavor intensity (p>0.05). BQ vs NBQ sources had no effect on tenderness or juiciness (p>0.05). Differences in tenderness, juiciness, meat-flavor intensity and WBS were found among the five meat cuts (P<0.05).