Effects of boning method and postmortem aging on meat quality characteristics of pork loin

This work investigated the effects of boning method and postmortem aging on pork loin color, shearing value and sensory attributes. Two experiments were assigned. In Experiment I, 30 Chinese native black pigs were slaughtered and their carcasses were divided into three groups: (i) hot-boning: carcasses were fabricated within 45 min postmortem just after dressing; (ii) cold boning at 24 h: carcasses were fabricated after chilling at 0°C for 24 h; (iii) cold boning at 36 h: carcasses were fabricated after chilling at 0°C for 36 h. In Experiment II, right sides of the second group in Experiment I were used and primal cuts were vacuum packed and aged for 1 day, 8 days and 16 days. Pork loins ( Longissimus lumborum ) were used for color measurement, shearing test, and sensory evaluation. Among three boning methods, cold-boning at 36 h postmortem had the advantages of giving muscles a better color, the lowest cooking loss and cooked shearing value, and the highest sensory tenderness, juiciness, flavor and overall liking. Postmortem aging could improve pork quality characteristics, but it is not the fact that the longer aging time is, the better pork quality would be. Eight days may be enough to obtain an acceptable sensory attribute. These results are meaningful for pork processing and pork consumption.     

The influence of aging and low zinc nutrition on the choroid in the pig: I. The melanocyte

The effects of low zinc nutrition and aging on central choroidal melanocytes were examined in the pig. Three populations of pigs (young, pregnant and aged), were maintained on either control (C) or low zinc (LZ) diets. Twenty-five weanling boars were sacrificed at 2, 4, 8, 10, and 12-month intervals, and nine pregnant sows and eight aged sows were sacrificed after a 6-month interval. Melanocytes of the central choroid were morphologically and morphometrically examined. The melanocyte was found to be conservative in its form, which was mostly elliptical longitudinal profile, throughout the different age populations that were fed the C diet. Morphometric observations revealed that this cell type increased in size in the oldest animals, having been 40% greater than that in the younger two populations. However, the overall percentage area occupied by melanocytes remained the same throughout all age groups. In the animals that were fed the LZ diets, a large subpopulation of choroidal melanocytes was oval to round in shape in the pregnant and aged groups. Many members of this subpopulation possessed less opaque pigment than the elliptically shaped cell. Measurements of the size and percentage area occupied in these oldest groups increased significantly. In addition to the change of size, shape and melanin opaqueness, unusually large melanosomes were consistently observed in the pregnant and aged LZ groups. Low zinc nutrition had a remarkable age-related impact on the usually quiescent melanocyte.     

The influence of aging and low zinc nutrition on the choroid in the pig: II. The melanosome

The effects of low zinc nutrition and aging on central choroidal melanosomes were examined in the pig. Melanosomes of central choroidal melanocytes were morphologically and morphometrically examined in three populations of pigs (young, pregnant and aged), that were maintained on either control (C) or low zinc (LZ) diets. In C groups, the typical melanosomes decreased in size with age, although a subpopulation of larger melanosomes occurred in the oldest group. In contrast, the melanosomes of the animals on LZ diets increased in size significantly in the adult groups. The melanosomes in the pregnant and aged groups were 65% and 30–40% greater than those of the age-matched C groups. Extremely large melanosomes were frequently encountered in adult LZ choroidal melanocytes. Melanogenesis of these large bodies included the formation of one or more outer shells. Fusion of adjacent large melanosomes was also observed. Melanolysosomal-like bodies were observed, particularly among the pigmented cells in the large blood vessel region of C and LZ adults. Melanin dynamics, i.e. its production and breakdown, occurred within choroidal melanocytes throughout much of the lifespan of the pig. This dynamic was greatly influenced by low zinc nutrition, resulting in unusual and aberrant melanin activity.     

积极老龄化背景下安徽省养老服务政策研究——基于2002—2022年政策文本的分析

在积极老龄化背景下,推动养老服务政策优化升级是新时代老龄社会治理的迫切需要。运用文献计量法和内容分析法,从外部要素和内在属性两方面,对安徽省2002-2022年39份政策文本进行综合量化研究发现,养老服务政策发展历经三个时期;发文主体之间是跟随型府际关系与协作型府际关系并存的合作模式;养老服务政策可执行性和可操作性有待加强;“老有所养”“老有所医”是养老服务政策核心;养老服务政策工具使用结构失衡。未来制定养老服务政策要坚持问题导向,加强协作配合;强化需求认识,拓展需求空间;健全政策工具协调网络,规划合理工具组合方式。     

适老化背景下的街道景观改造研究——以南京市溧水区晶桥镇为例

通过对适老化小镇的景观改造研究,从康养人群对街道景观的体验需求、生活需求、审美需 求等方面出发。以南京市溧水区晶桥镇街道景观为例,通过分析街道景观改造中各方面的影响,对如 何营造功能合理、符合康养人群生活特点的街道环境,如何重塑旧街道景观的新定位提出建设性意 见。     

对当前农村养老问题的思考

论述了我国农村养老面临的诸多挑战,根据当前农村养老的实际状况,提出了改善我国农村养老保障的对策和建议。     

论撒切尔政府养老金制度改革的动因

在英国养老金制度发展史上, 1986 年的撒切尔政府养老金制度改革是一次具有重要意义的改革。促成这次改革是多种因素的综合: 人口老龄化使养老金支出不断增长; 社会保障制度发展与经济发展水平之间的不协调; 养老金制度本身的缺陷; 哈耶克的思想和货币主义理论对撒切尔的巨大影响; 政界的右转。     

更新修剪对衰老‘富士’苹果枝条生长及树冠结构的影响

为探寻更新修剪对衰老期‘富士’苹果枝条生长及树冠结构的影响,以长放修剪为对照,测定了枝条生长动态、树冠结构及果实产量和品质。结果表明:不同修剪的发育枝和果台副梢生长动态均为单峰曲线。更新修剪的发育枝长度和粗度分别增加了63.92%和20.93%,果台副梢分别增加了51.14%和9.76%;相同树冠体积徒长枝,长、中枝和营养枝的数量分别增加了132.93%、82.59%、54.47%和76.84%,短枝、叶丛枝和结果枝分别降低了28.84%、31.57%和22.64%;单株树冠体积缩小了14.53%,枝条总量降低了27.82%;叶面积指数、平均叶倾角和消光系数分别提高了9.64%、153.22%和2.97%,冠层开度降低了13.15%;单果质量和产量分别提高了23.61%和30.02%,但对果实食用品质无显著影响。     

高温老化处理对棉花种子抗逆酶活性的影响

以99B、晋棉32号、中棉41号3个棉花品种为材料,采用人工高温老化处理,研究了棉花种子在老化过程中种子活力、电导率、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性以及丙二醛(MDA)含量的变化。结果表明,高温((45±1)℃)、高湿(相对湿度100%)密闭环境条件下,随着高温处理时间的延长,3个棉花品种的种子活力均表现出先升高而后逐渐降低的变化趋势,而电导率呈逐渐上升趋势;种子在高温处理过程中,POD,SOD,MDA活性均呈双峰曲线,MDA含量变化与POD,SOD活性变化呈负相关。     

花生四烯酸高产突变株5L罐发酵及菌丝老化研究

[目的]研究花生四烯酸高产突变株的发酵及菌丝老化特性。[方法]对1株经诱变获得的花生四烯酸高产突变株A1．13进行5L罐发酵试验,考察不同培养条件对发酵产物的影响。[结果]碳源一次性过量加入并改变培养温度,可使该菌株花生四烯酸产量提高至602．99mg／L;发酵菌丝体在4℃条件下老化15d后,花生四烯酸产量达885．16mg/L。大豆油、花生油、玉米油、葵花籽油和芝麻油5种植物油均可起到消泡作用,添加浓度4％葵花籽油效果最佳,与对照相比,菌丝生物量和花生四烯酸产量分别提高了124％和22％。[结论]该研究可为突变株A1．13工业化发酵产花生四烯酸提供理论依据和现实参考。