预乳化鸡皮对鸡肉香肠品质的影响

以添加鸡皮为对照组（C0,鸡皮添加量30%（质量分数,下同））,添加预乳化鸡皮为处理组,即T1组（鸡皮20%＋预乳化鸡皮10%）、T2组（鸡皮15%＋预乳化鸡皮15%）、T3组（鸡皮10%＋预乳化鸡皮20%）和T4组（预乳化鸡皮30%）,研究预乳化鸡皮对鸡肉香肠品质特性的影响。测定的品质特性指标包括近似组成、蒸煮损失、乳化稳定性、pH值、表观黏度、色泽、质构特性和感官特性。结果表明：随着鸡皮与预乳化鸡皮添加比例的变化,鸡肉香肠的水分含量、脂肪含量、蒸煮损失、乳化稳定性、亮度、质构特性、表观黏度和整体可接受性等指标均有所改变。T2组的水分含量最高（P＜0.05）,C0和T4组的水分含量最低（P＜0.05）;C0组的脂肪含量高于各处理组（P＜0.05）;T2组的蒸煮损失、总可表达流体和脂肪分离比例、硬度、弹性和黏聚性具有最低值（P＜0.05）;各处理组的总体可接受性评分均显著高于对照组（P＜0.05）。预乳化鸡皮的添加可改善鸡肉香肠的品质特性,其中鸡皮与预乳化鸡皮的最适宜添加比例为1∶1。     

Cholesterol Content and Methods for Cholesterol Determination in Meat and Poultry

Abstract: Available data for cholesterol content of beef, pork, poultry, and processed meat products were reported. Although the cholesterol concentration in meat and poultry can be influenced by various factors, effects of animal species, muscle fiber type, and muscle fat content are focused on in this review. Oxidative red muscles tend to have greater total lipid and cholesterol contents, although differences in the same types of muscles or cuts have been reported. Moreover, contradictory results among various studies suggest that unless there are pronounced changes in muscle structure and composition, cholesterol content is unlikely to be affected. Second, multiple issues in cholesterol analysis, including sample preparation, detection, and quantification, were evaluated. Cholesterol content of meat and poultry has been determined mostly by colorimetry and chromatography, although the latter has become predominant because of technological advances and method performance. Direct saponification has been the preferred method for hydrolyzing samples because of cost‐ and time‐effectiveness. The extraction solvent varies, but toluene seems to provide sufficient recovery in a single extraction, although the possible formation of an emulsion associated with using toluene requires experience in postsaponification manipulation. The most commonly used internal standard is 5α‐cholestane, although its behavior is not identical to that of cholesterol. Cholesterol can be analyzed routinely by gas chromatography (GC)‐flame ionization detector without derivatization; however, other methods, especially high‐performance liquid chromatography (HPLC) coupled with different detectors, can also be used. For research purposes, HPLC‐ultraviolet/Visible/photodiode array detector with nondestructiveness is preferred, especially when cholesterol must be separated from other coexisting compounds such as tocopherols. More advanced methods, such as GC/HPLC‐isotope dilution/mass spectrometry, are primarily used for quality control purposes.     

纯碱法制备鸡皮明胶的工艺优化研究

对纯碱法提取鸡皮明胶进行研究,以碱浓度、浸碱时间、提胶温度、提胶时间为单因素,以提取率为响应值。鸡皮明胶碱法制备的最佳工艺条件为:碱浓度0.07 mol/L、浸碱时间30.00 h、提胶温度65.00℃、提胶时间2.00 h。此最佳条件下所得明胶的提取率为(12.03±0.47)%。     

鸡皮明胶的提取工艺研究

本文主要研究了酸法提取鸡皮明胶的工艺条件。通过单因素和正交试验设计确定提取鸡皮明胶的优化工艺条件,结果表明,盐酸浓度3.0%、浸酸温度28℃、提胶料液比1∶5、提胶pH值为3的提取效果最佳,明胶提取率为9.47%。     

拜城油鸡鸡肉及鸡皮脂肪酸组成分析研究

以新疆拜城油鸡为材料,对其鸡皮和鸡肉脂肪酸组成进行分析,与拜城土鸡及肉鸡进行比较研究。结果显示,拜城油鸡鸡皮和鸡肉总脂质中各检出25种脂肪酸。鸡皮总脂肪酸组成中不饱和脂肪酸的比例鸡种间差异较小,但在拜城油鸡鸡肉中的不饱和脂肪酸比例显著高于市售肉鸡。鸡皮和鸡肉中的主要不饱和脂肪酸为C16:1(9),C18:1(9),C18:1(11),C18:2,C18:3和C20:4,其中拜城油鸡的C18:3和C20:4含量均高于拜城土鸡和肉鸡。对于不同月龄的拜城油鸡脂肪酸含量而言,月龄大的拜城油鸡鸡肉的不饱和脂肪酸含量显著低于月龄小的拜城油鸡。     

Chicken Skin Composition As Affected By Aqueous Washing

Broiler skin was washed in either 0.1M sodium chloride (pH 7.0) or 0.5% sodium bicarbonate buffer (pH 8.4) to reduce water-soluble proteins and fat. Washing increased moisture and total protein content (P<0.05) of skin. Ash content was lower (P<0.05) in skin washed in 0.5% sodium bicarbonate buffer compared to unwashed and 0.1M sodium chloride washed skin. Fat content decreased (P<0.05) following washing. Salt extractable proteins and collagen content remaining in skin increased following washing (P<0.05). Water-soluble proteins remaining in washed skin were lower (P<0.05). SDS-PAGE gel patterns for salt extractable proteins remaining in skin after washing revealed more intense bands in regions of myosin (200K daltons), M-proteins (165K daltons) and C-protein (135–140K daltons) and 31-45K daltons.     

Volatiles in Skin of Low Dose Irradiated Fresh Chicken

Fresh chickens were irradiated with up to 1200 krad at 0–5°C. Volatile compounds from the skin and subcutaneous fat of these chickens, and from unirradiated controls, were analyzed by gas chromatography. Acceptability of the odor of the chickens was also evaluated. Other samples (0 and 300 krad) were evaluated by chemical and sensory analysis after storage at 4°C. Analysis of volatiles indicated that levels of octane, l-octene, hexanal, and nonane increased regularly with radiation dose. Amount of total volatiles was greater in unstored irradiated samples than in controls, but this was reversed after storage. After 14 days, the irradiated sample still had acceptable odor, while the control ahd severely deteriorated.     

Quantification of Three Cholesterol Oxidation Products in Raw Meat and Chicken

Raw veal, beef, pork, and chicken muscle tissues were extracted by a modified dry column procedure in which silicic acid was incorporated in the trap of the column. This method separated cholesterol derivatives from the bulk of neutral lipids, phospholipids and cholesterol. Isolation of sterols by preparative thin layer chromatography followed by quantification by direct on-column capillary gas chromatography permitted measurement of 7-ketocholesterol, cholesterol 5α, 6α-epoxide, and cholesterol 5β 6β-epoxide at concentrations less than 1 ppm. All muscle tissues contained the three cholesterol products in measurable quantities. 7-Ketocholesterol constituted more than 50% of the oxidation products in all samples.     

GC-MS分析新疆拜城油鸡和南京土鸡鸡皮脂质中脂肪酸组成

分析比较新疆拜城油鸡和南京土鸡鸡皮总脂质和磷脂的含量及脂肪酸组成。用溶剂提取法分别提取2 种鸡皮的总脂质和磷脂,将提取的脂质经甲酯化后,利用气相色谱-质谱分析其脂肪酸组成。结果显示,南京土鸡鸡皮总脂质含量和磷脂含量分别为35.56%和7.71%,拜城油鸡鸡皮中总脂质含量和磷脂含量分别为42.65%和8.95%,均高于南京土鸡。南京土鸡与拜城油鸡鸡皮总脂质中各含有25 种脂肪酸,主要包含油酸、亚油酸、棕榈酸、硬脂酸、棕榈烯酸;2 种鸡鸡皮磷脂中均含有10 种脂肪酸,主要包含棕榈酸、油酸、硬脂酸和亚油酸。2 种鸡的鸡皮油脂脂肪酸的种类相同,但各脂肪酸含量有所差异;脂肪酸饱和程度比例基本相似,但南京土鸡鸡皮磷脂中不饱和脂肪酸和亚油酸含量高于拜城油鸡。     

不同饲料喂养鸡蛋中胆固醇的含量测定

对A,B,C,D四组不同饲料喂养新鲜鸡蛋的胆固醇含量进行测定,比较鸡蛋的平均重量、蛋清相对重量、蛋黄相对重量、蛋壳相对重量、蛋壳厚度.筛选出胆固醇含量较低的营养保健型鸡蛋.结果表明:A、B组的胆固醇含量偏高.C和D组的胆固醇含量较低,所有其他检测指标基本上没有差异.综合营养和经济因素,D组的鸡蛋更适宜于加工生产.     

Comparison of Volatiles Produced by Selected Pseudomonads on Chicken Skin

Four pseudomonad cultures (one P. putida, one nonpigmented, and two P. fluorescens) were isolated from spoiled chicken breasts held at 2–6°C for 14 days. Each culture was grown on psychrotroph-free chicken skin for 14 days at 2–6°C. The volatiles produced by each organism were separated by high-resolution gas chromatography and identified by mass spectrometry. Some of the more significant volatile spoilage compounds produced by these microorganisms were sulfur-containing, e.g. methanethiol, dimethyl sulfide, propylene sulfide, and dimethyl disulfide.     

Cholesterol Content of Restructured Pork/Soy Hull Mixture

The effect of convective heat processing was studied on cholesterol and its oxides in a restructured pork/soy hull model system. Products were analyzed from 30 different time-temperature conditions of processing. Following lipid extraction, GC-MS was used for analysis of cholesterol and its oxides. No cholesterol oxides were found at 2 ppm in the product with any of the 30 time-temperature profiles, ranging from 19 -89.6 min of heat processing, and 9–97°C final product temperatures. Cholesterol in heat-processed samples ranged from 45.43–66.47 mg/l00g. Positive correlations were found between final temperatures and fat and cholesterol content.     

基于中波近红外光谱构建生鲜鸡肉胆固醇定量分析模型

通过采集市售生鲜鸡肉样品在中波近红外区的光谱信息,采用偏最小二乘法构建胆固醇定量分析模型,并评价模型的预测准确性。在建模过程中,讨论异常样品剔除与组合预处理方法等优化措施对模型的影响。参模样品经2 次异常样本剔除并以SG（Savitzky-Golay）一阶导数、SG平滑及去趋势校正进行预处理后,获得了最佳生鲜鸡肉胆固醇定量分析模型,其中：校正标准差（standard error of calibration,SEC）为4.534 8、校正集相关系数为0.919 7、预测标准差（standard error of prediction,SEP）为7.437 5、验证集相关系数为0.812 0、范围误差比为2.844 7、相对预测标准差为9.44%、主因子数为5、SEP/SEC为1.640 1。对检验集样品预测的结果表明,基于中波近红外光谱构建的胆固醇定量分析模型的预测性能较好（P＞0.05）,特别是在60～100 mg/100 g含量区间,可应用于对市售生鲜鸡肉及产品胆固醇的检测。     

Selenium Content of Chicken Meat as Affected by Cooking

Twelve dressed chickens of the same flock were quartered and prepared by four cooking treatments: microwaving, conventional oven cooking, broiling, and panfrying. The mean value of selenium (fluorometic method) in raw chicken was 0.38 μg/g dry weight, with no significant differences between white and dark meat. There was insignificant loss of selenium due to cooking. Cooked chicken breast had a significantly higher level of dialysable selenium compounds (MW < 2000 daltons) than raw chicken.     

多种酶复合制备鸡皮胶原蛋白短肽

以鸡皮为原料,采用酶法提取胶原蛋白肽。研究了酶的种类、加酶量、酶解时间、酶解温度以及pH值对水解度和多肽质量浓度的影响,采用正交实验对酶解条件进行了优化。结果表明,当采用木瓜蛋白酶+胰蛋白酶+风味蛋白酶复合水解,加酶量为0.9%、酶解时间3 h、酶解温度45℃及pH为7时,为酶解最佳条件。     

Purine Content of Raw and Roasted Chicken Broiler Meat

Adenine, guanine and hypoxanthine were determined in raw and roasted broiler parts. The levels of adenine and guanine increased slightly when the meat was cooked. These increases were attributed to moisture and fat losses by the tissues during roasting. The level of hypoxanthine remained constant or decreased in the tissues because some of the purine was removed with the cooking juices. The cooking juices were found to contain high levels of hypoxanthine and only trace amounts of adenine and guanine.     

Cholesterol Content and Fatty Acids Composition of Mangalitsa Pork Meat

The aim of this study was to examine variability in cholesterol content and fatty acid composition in musculuslongissimus (MLLT) of various genotypes of pigs. Out of 30 male castrated animals used in the trial, 20 were Mangalitsa pigs (Swallow Belly - SBM and White - WM) while 10 were of the Swedish Landrace breed – SL. The representative of pig meat breeds, SL had significantly less cholesterol in MLLT compared to SBM and WM pigs. The total monounsaturated fatty acids (MUFA) and unsaturated fatty acids (USFA) content was higher in SBM and WM than in SL pigs (p< 0.001).     

GC-MS法测定食品中胆固醇含量的研究

目的:建立一种简单、快速而又重现性好的胆固醇测定方法,以监测食品中胆固醇的确切含量。方法:饼干样品经石油醚萃取后用50% KOH-乙醇（40:12）皂化后用乙醚二次萃取,上层溶液水洗至中性后无水Na2SO4脱水过滤并浓缩至1ml,氮气吹干后用正己烷溶解,注入GC-MS进行定量分析。研究结果显示,该方法胆固醇的回收率在96．64%～100．13%之间,平均值为98．43%。方法的精密度高,重现性好,标准偏差S=0．02193,相对标准偏差RSD（n=6）=1．4393%,最低检测限为0．0659μg/ml,最小定量限为0．22μg/ml:若以称样量0．5g计算,方法的最低检测限为1．318μg/g。     

Determination of Cholesterol Content in Waste Fat by Dual-wavelength Spectrophotometry

[Objective]The aim was to find a way to measure the cholesterol content in deserted oil.[Method]Dual-wavelength spectrophotometry method was used for the determ...