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1.
《Journal of dairy science》2022,105(5):4314-4323
We tested the hypothesis that the size of a beef cattle population destined for use on dairy females is smaller under optimum-contribution selection (OCS) than under truncation selection (TRS) at the same genetic gain (ΔG) and the same rate of inbreeding (ΔF). We used stochastic simulation to estimate true ΔG realized at a 0.005 ΔF in breeding schemes with OCS or TRS. The schemes for the beef cattle population also differed in the number of purebred offspring per dam and the total number of purebred offspring per generation. Dams of the next generation were exclusively selected among the one-year-old heifers. All dams were donors for embryo transfer and produced a maximum of 5 or 10 offspring. The total number of purebred offspring per generation was: 400, 800, 1,600 or 4,000 calves, and it was used as a measure of population size. Rate of inbreeding was predicted and controlled using pedigree relationships. Each OCS (TRS) scheme was simulated for 10 discrete generations and replicated 100 (200) times. The OCS scheme and the TRS scheme with a maximum of 10 offspring per dam required approximately 783 and 1,257 purebred offspring per generation to realize a true ΔG of €14 and a ΔF of 0.005 per generation. Schemes with a maximum of 5 offspring per dam required more purebred offspring per generation to realize a similar true ΔG and a similar ΔF. Our results show that OCS and multiple ovulation and embryo transfer act on selection intensity through different mechanisms to achieve fewer selection candidates and fewer selected sires and dams than under TRS at the same ΔG and a fixed ΔF. Therefore, we advocate the use of a breeding scheme with OCS and multiple ovulation and embryo transfer for beef cattle destined for use on dairy females because it is favorable both from an economic perspective and a carbon footprint perspective. 相似文献
2.
Huan-yu Tao Qin Hu Yi Wu Peng Han Xiaobo Liang 《International Journal of Food Science & Technology》2021,56(8):3807-3813
A strain, Rahnella aquatilis L103, which was isolated from the soil around the roots of mushrooms, produced antibacterial protein though fermentation. This protein has broad antibacterial spectrum towards gram-positive and gram-negative bacteria. The protein has a significant antioxidant capacity on scavenging ABTS+· (82.5%, 120 μg mL−1), DPPH· (64.1%, 600 μg mL−1) and OH· (60.1%, 750 μg mL−1) as well. The protein was considered to be safe within concentration of 150 μg mL−1 as shown by MTT results and was applied to beef refrigerated preservation. The treatment group presented lower total viable counts (TVC), total volatile basic nitrogen (TVB-N), 2-thiobarbituric acid (TBA), meanwhile, higher sensory score and longer shelf life (2 days) compared with the control group (P < 0.05). The results indicated that the protein under safe concentration was beneficial to beef preservation. 相似文献
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采用液相色谱-串联质谱技术分析我国部分地区市售牛肉、牛奶中可的松和氢化可的松的含量水平。均质的牛肉或牛奶样品在乙酸-乙酸钠缓冲液中酶解后用甲醇提取,提取液用石墨化碳黑固相萃取小柱和氨基固相萃取小柱净化,洗脱液氮吹至干并用甲醇溶液定容,液相色谱-串联质谱测定。采用SPSS?21.0软件进行数据分析。对采自我国9?省市的346?份牛肉和牛奶样品进行检测,分析牛肉和牛奶中可的松和氢化可的松的存在水平。牛肉和牛奶中均检出可的松和氢化可的松,检出率在86.1%~100.0%之间,检出含量范围为0.02~74.88?μg/kg。牛肉中可的松和氢化可的松的含量平均值(中位数)分别为1.69(1.14)?μg/kg和12.16(8.14)?μg/kg,牛奶中可的松和氢化可的松的含量平均值(中位数)分别为0.23(0.23)?μg/kg和0.72(0.72)?μg/kg。牛肉和牛奶中氢化可的松与可的松的含量均呈显著正相关。 相似文献
4.
Improvement of tenderness and water holding capacity of spiced beef by the application of ultrasound during cooking 下载免费PDF全文
Yunhe Zou Wangang Zhang Dacheng Kang Guanghong Zhou 《International Journal of Food Science & Technology》2018,53(3):828-836
The aim of this study was to assess the effects of power ultrasound‐assisted (0, 400, 600, 800 and 1000 W, frequency of 20 kHz) cooking (80, 100, 120 min) on spiced beef. The results showed that power ultrasound could significantly increase the salt content (P < 0.05). For water holding capacity, the ultrasonic treatment could significantly reduce the pressure loss and free water content while improving the immobilised water content (P < 0.05). And ultrasonic treatment improved hardness compared with control (P < 0.05). However, the effects on the springiness, the chewiness and the resilience of the spiced beef were not significant (P > 0.05). As for microstructure, the myofibrils of beef were ruptured by ultrasonic treatment along with the Z‐lines leading to the muscle swelling. The results indicated that the application of ultrasound during cooking could effectively promote the penetration of salt, improve the water holding capacity and ameliorate the tenderness of spiced beef. 相似文献
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Małgorzata Kowalska Anna Żbikowska Bolesław Kowalski 《Journal of the American Oil Chemists' Society》2014,91(10):1703-1710
The aim of this work was to develop a new fat by enzymatic interesterification of mutton tallow with rapeseed oil. It was assumed that by inducing hydrolysis of fats by addition of water to the enzymatic preparation (8, 10, 15 wt%) natural emulsifiers would be produced in the reaction environment. Fat blends obtained from the enzymatic reactions were evaluated as a fat base for emulsion systems. It was found that the fat resulting from interesterification in the presence of Lipozyme RM IM (immobilized lipase from Rhizomucor miehei, Novozymes Bagsvaerd, Denmark) with 15 wt% of water possessed the highest content of polar fraction (MAG and DAG), and served as the most suitable blend for emulsification, producing emulsions that exhibited the highest stability. 相似文献
8.
《Food Control》2017
Escherichia coli O157:H7 are a well-known intestinal foodborne pathogen which were responsible for numerous foodborne illness outbreaks. Uropathogenic E. coli (UPEC) are common contaminants in meat and poultry, and may cause urinary tract infections after colonizing the gastrointestinal tract followed by accidental transfer of contaminated feces from the anus to the urethra. High pressure processing (HPP) has been demonstrated an effective means in reducing pathogenic E. coli levels in meat and poultry. Citral, an antimicrobial, also demonstrated some inactivation effect on pathogenic E. coli in ground beef (ca. 0.5–1.0 log CFU/g reduction at 1% w/w without HPP). With HPP alone, to achieve 5 log CFU/g reduction required a 500 MPa level and 15 min (for both O157:H7 and UPEC). However, 1% of citral addition may lower the pressure requirement to 380 MPa and 15 min which could reduce the food quality damage. To effectively inactivate E. coli O157:H7 and UPEC in meat, high pressure processing (HPP) in combination with the antimicrobial citral was studied. Ground beef inoculated with E. coli O157:H7 or UPEC were treated at different HPP conditions (250–350 MPa; 10–20 min), and citral (0.75–1.25%, w/w) following a central composite experimental design. Quadratic linear regression equations were developed to describe and predict the reductions of E. coli O157:H7 (R2 = 0.93, p < 0.001) and UPEC (R2 = 0.92, p < 0.001). Dimensionless nonlinear models consisting of three impact factors were also developed and compared with the linear models. These models were experimentally validated. Citral enhanced the inactivation of pathogenic E. coli, increasing the effectiveness of the HPP process. The models may assist the food industry and regulatory agencies in risk assessment of E. coli O157:H7 and UPEC on ground meats. 相似文献
9.
Agnieszka Owczarek‐Fendor An Vermeulen Ilse Van Bree Markus Eriksson Stefaan Lescouhier Stefaan De Smet Bruno De Meulenaer Frank Devlieghere 《International Journal of Food Science & Technology》2014,49(4):1090-1098
The objective of this study was to evaluate the influence of two different vacuum ageing times (7 and 14 days) and the impact of the modified atmosphere packaging (MAP) configuration (gas/product ratios: 0.5 and 1 and gas composition: 70% O2 + 30% CO2 and 40% O2 + 30% CO2 + 30% N2) on the quality of fresh beef during subsequent storage at 4 °C. For this purpose, three separate experiments were performed. For each experiment, two different muscles (Longissimus dorsi and Biceps femoris) were sampled from four double‐muscled Belgian Blue beef carcasses. Next to colour, also the evolution in microbial load, pH, O2 and CO2 in the headspace and lipid oxidation at the meat surface were evaluated. A vacuum ageing for 14 days compared with 7 days resulted in a higher initial microbial load on the day of MAP packaging, which resulted finally in a significantly shorter shelf life. This ageing effect was less pronounced on the colour stability and lipid oxidation of the meat samples. No significant influence of the packaging configuration on any of the analysed parameters (colour, microbial load, pH and lipid oxidation at the meat surface) was observed. 相似文献
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