检索结果-南通市图书馆

Portable Analyzer for Rapid Analysis of Total Protein, Fat and Lactose Contents in raw milk Measured by Non-dispersive Short-wave Near-infrared Spectrometry

引用

Chemical Research in Chinese Universities 2013年第1期29卷 15-19页

作者： FENG Xu-dong SU Rui XU Nan WANG Xing-hua YU Ai-min ZHANG Han-qi CAO Yan-bo College of Chemistry Jilin University Changchun 130012 P. R. China

A novel portable analyzer for raw milk quality control during the material purchase at dairy plants was developed, by which the percentages（mass fraction） of main components including total protein, fat, and lactose of an unhomogenized milk sample could be determinated in 1 min with the help of non-dispersive short-wave near-infrared （NDSWNIR） spectrometry in a wavelength range from 600 nm to 1100 nm and multivariate calibration. The analyzer was designed with a single-beam optical system, which comprised a temperature control module, a multi-channel narrow-band light source（16 wavelengths）, a glass absorption cell with 15 mm sample thickness, a silicon photodiode detector, several compound lenses and a recorder module. A total of 80 raw milk samples were collected at a dairy farm twice a month for 4 months. The samples were scanned with a common UV-Vis-NIR spectrometer and analyzed according to China GB standard methods. The uninformative variables elimination（UVE） method was carried out on the spectrum data and the percentages of main components of all the samples to choose the peak emitting wavelength of each channel of the light source. Another 90 raw milk samples were collected from the same dairy farm thrice a month for 3 months. The samples were analyzed according to China GB standard methods and with the proposed analyzer. The percentages of the main components and the NDSWNIR absorption data of the samples were used for the construction and validation of the multivariate calibration model with partial least squares（PLS） method. The root-mean-square errors of prediction（RMSEP） of total protein, fat and lactose were 0.201, 0.172 and 0.247 and the coefficients of correlation（R） were 0.932, 0.981 and 0.933, respectively.

关键词： Portable analyzer raw milk Non-dispersive short-wave near-infrared(NDSWNIR) spectrometry Multiva-riate calibration

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Development of a test strip for rapid detection of lactoperoxidase in raw milk

引用

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2015年第8期16卷 672-679页

作者： Hong-xia CHE Bo TIAN Li-na BAI Li-ming CHENG Li-li LIU Xiao-na ZHANG Zhan-mei JIANG Xiao-xi XU Key Laboratory of Dairy Science (KLDS) Ministry of Education Northeast Agricultural University

Traditional methods for detecting lactoperoxidase （LP） are complex and time-consuming, so a test strip was made based on the enzymatic reaction principle to enable quick and convenient detection of LP in raw milk. In this study 0.1 mol/L citric acid （CA）/0.2 mol/L disodium hydrogen phosphate （NAP） buffer solution （pH 5.0）, 22 mmol/L 3,3＇,5,5＇-tetramethylbenzidine （TMB）, 0.6 mmol/L hydrogen peroxide （H202）, and 0.5% Tween-20 or 0.3% cetyltri- methyl ammonium bromide （CTAB） were optimal for preparing a quick, sensitive, and accurate LP test strip. The coefficient of variation （CV） of the estimated LP concentrations ranged from 2.47% to 6.72% and the minimum LP concentration detected by the test strip was 1-2 mg/L. Estimates of active LP in sixteen raw milk samples obtained using the test strip or the TMB method showed a good correlation （c=0.9776）. So the test strip provides a quick, convenient, and accurate method for detecting the LP concentration of raw milk.

关键词： Lactoperoxidase Test strip Rapid detection raw milk 3 3' 5 5'-Tetramethylbenzidine (TMB)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Spoilage potential of psychrotrophic bacteria isolated from raw milk and the thermo-stability of their enzymes

引用

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2018年第8期19卷 630-642页

作者： Lei YUAN Faizan A.SADIQ Tong-jie LIU Yang LI Jing-si GU Huan-yi YANG Guo-qing HE College of Biosystems Engineering and Food Science Zhejiang University

The storage and transportation of raw milk at low temperatures promote the growth of psychrotrophic bacteria and the production of thermo-stable enzymes, which pose great threats to the quality and shelf-life of dairy products. Though many studies have been carried out on the spoilage potential of psychrotrophic bacteria and the thermo-stabUities of the enzymes they produce, further detailed studies are needed to devise an effective strategy to avoid dairy spoilage. The purpose of this study was to explore the spoilage potential of psychrotrophic bacteria from Chinese raw milk samples at both room temperature （28 ℃） and refrigerated temperature （7 ℃）. Species of Yersinia, Pseudomonas, Serratia, and Chryseobacterium showed high proteolytic activity. The highest proteolytic activity was shown by Yersinia intermedia followed by Pseudomonas fluorescens （d）. Lipolytic activity was high in isolates of Acinetobacter, and the highest in Acinetobacter guillouiae. Certain isolates showed positive ^-galactosidase and phospholipase activity. Strains belonging to the same species sometimes showed markedly different phenotypic characteristics. Proteases and lipases produced by psychrotrophic bacteria retained activity after heat treatment at 70, 80, or 90 ℃, and proteases appeared to be more heat-stable than lipases. For these reasons, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry. The results of this study provide valuable data about the spoilage potential of bacterial strains in raw milk and the thermal resistance of the enzymes they produce.

关键词： Spoilage enzyme Psychrotrophic bacteria raw milk Thermo-stability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Detection of Glucomacropeptide in raw milk Adulterated with Cheese Whey in Ecuador

引用

Food and Nutrition Sciences 2017年第6期8卷 579-590页

作者： Byron Humberto Puga-Torres Samantha Michele Morales-Arciniega Luis Fabián Núnez Naranjo David Isaías De la Torre-Duque Rolando Martin Campos-Vallejo Silvana Hipatia Santander-Parra Enrique César Vayas-Machado School of Veterinary Medicine and Animal Science Central University of EcuadorQuitoEcuador School of Engineering of Livestock Industries Chimborazo Polytechnic SchoolRiobambaEcuador Department of Experimental and Comparative Pathology School of Veterinary Medicine and Animal ScienceUniversity of Sao PauloSao PauloBrazil Career of Integral Agricultural Development Faculty of Agricultural Industries and Environmental SciencesCarchi Polytechnic UniversityTulcanEcuador

milk is one of the products that can be adulterated in many ways affecting the quality of this and its derivatives. Glucomacropeptide (GMP) is a protein that is found only in the whey from the production of fresh cheese, enzymatically obtained from the coagulation of casein and which is commonly used to adulterate fresh or powdered milk. The aim of this study was to determine the adulteration of milk with cheese whey thought a molecular approach, where the glucomacropeptide was collected by sequential precipitation with trichloroacetic acid (ATC) and detected by polyacrylamidododecylsulfate gel electrophoresis (PAGE-SDS), using samples of fresh milk, intentionally adulterated with serum in the proportion of 0%, 1%, 5%, 10% and 15%. The results obtained showed that the detection of glucomacropeptide by electrophoresis was positive in all samples of adulterated milk, evidencing a band of 20.9 kDa in the reading, corresponding to the molecular weight of the GMP, showing that the technique used determines the adulteration in the milk, in a specific and sensitive way, also shows that in the evaluation of physical-chemical and microbiological parameters of milk, there are no significant differences between treatments, except for the pH that tends to decrease as the percentage of serum in the milk increases.

关键词： Glucomacropeptide raw milk Whey Cheese milk Adulteration

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Novel and Reliable Spectrophotometric Method for Determination of Lactoperoxidase Activity in raw milk

引用

Journal of Northeast Agricultural University(English Edition) 2017年第2期24卷 66-73页

作者： Jiang Zhan-mei Che Hong-xia Yang Nan Yuan Xiang-ying Li Xue-yan Zhang Xin-liu Key Laboratory of Dairy Science Ministry of Education Northeast Agricultural University Harbin 150030 China

With 3, 3’5, 5’-tetramethylbenzidine（TMB） as the detection substrate, a reliable and highly selective method was established and optimized for the determination of Lactoperoxidase（LP） activity in raw milk. The method was based on the enzymatic reaction principle, where hydrogen peroxide oxidated TMB in the presence of LP. The optimized conditions of this assay system were obtained, consisting of 20 mmol · L-1 TMB solution, 0.6 mmol · L-1 hydrogen peroxide and 0.1 mol · L-1 Citric Acid（CA）/0.2 mol · L-1 disodium hydrogen phosphate（Na P） buffer（pH 4.8）. TMB detection method was applied to the analysis of LP in milk samples with a practical working concentration range from 2 to 14 mg · L-1. The intra-and inter-batch variation coefficients were all below 5%, indicating a good repeatability. Confirmation test between TMB method and 2, 2-azinobi（3-ethylbenzothiazoline-6-sulphonate） diammonium salt（ABTS） method was carried out, and the results of TMB assay were in accordance with that of ABTS method.

关键词： lactoperoxidase activity 3 3'5 5'-tetramethylbenzidine (TMB) detection condition raw milk

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Selective Lactococcus Enumeration in raw milk

引用

Food and Nutrition Sciences 2013年第9期4卷 49-58页

作者： Laetitia Gemelas Véronique Rigobello Mai Huong Ly-Chatain Yann Demarigny Isara-Lyon Unité BioDyMIALyonFrance

The Lactococcus diversity in cow and goat raw milk was investigated. To do so, a protocol had to be established for the specific enumeration of lactococci. Eight agar media and one control medium were analysed to compare their proficiency in evaluating the Lactococcus population in raw milk: M17 Nal, Elliker, modified Elliker, PCA + milk, modified KCA, modified Chalmers, Turner, FSDA. The M17 medium was used as reference. Eighteen pure strains were tested on these media for their selectivity towards lactococci: six Lactococcus species or subspecies, three Leuconostoc, three Enterococcus, two Lactobacillus, one Streptococcus thermophilus, one Pseudomonas fluorescens, one Escherichia coli and one Staphylococcus aureus. All these bacteria were chosen for their regular presence in raw milk. The KCA medium proved to be the most selective towards lactococci, on condition that 1) we discriminated the colonies using the catalase test and 2) we subtracted the Enterococcus population counted on BEA. However, it was not possible to separate the Streptococcus from the Lactococcus colonies on KCA. The “Lactococcus-like” population including these two genera was estimated at a mean level of 3.18 log(cfu)/mL and 4.14 log(cfu)/mL in cow and goat raw milk respectively. This is consistent with the data already published.

关键词： Lactococcus Culture Media raw milk LAB Modified KCA

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Impact of the residues of detergents and disinfectants used in dairy farms on the results of inhibitor tests for raw milk

引用

Advances in Bioscience and Biotechnology 2013年第2期4卷 266-272页

作者： Joana Salomskiene Irena Macioniene Renata Zvirdauskiene Dovile Jonkuviene Kaunas University of Technology Food instituteKaunasLithuania

The aim of the study was to determine the impact of residues of detergents and disinfectants on the results of most commonly used inhibitor tests for raw milk. Microbiological test (Delvotest SP-NT) and three rapid tests (Charm 3 MRL BL/TET2, Charm ROSA MRL BL/TET and Penzym) were used in the study. Three concentrations (recommended by the manufacturer, 10 times lower and twice higher) of 36 detergents and disinfectants in raw milk were investigated. All methods did not detect concentrations of detergents and disinfectants of alkaline and acid origin 10 times lower than recommended by the manufacturer. 39% of the investigated substances of alkaline origin were detected by Delvotest SP-NT and Penzym;Charm tests showed non-typical results only. Delvotest SP-NT did not detect substances of acid origin;Penzym detected 50% of these substances, Charm tests showed only non-typical results. Delvotest SP-NT and Penzym appeared to be more sensitive to the substances used for teat hygiene and disinfection. The scope of rapid tests (receptor or enzymatic) does not cover the detection of detergent and disinfectant re- sidues in milk. However, according to the non-typical results of the test, it is possible to suspect the presence of these substances in milk. McNemar’s and Cochran’s Q tests were used for statistical analysis of the data.

关键词： Detergents Disinfectants Residues Sensitivity Inhibitor Tests raw milk

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Application of Colligative Properties in Quality Detection of Watering raw milk

引用

Animal Husbandry and Feed Science 2011年第2期3卷 42-44页

作者： LIN Fang-dong JIANG Zhen-ju CAO Rui School of Bioengineering Xihua University Chengdu 610039 China

[ Objective] To investigate the effects of different water amount on freezing point of raw milk. EMetbodl The freezing point of raw milk added water at different proportions was detected by SWC-LG freezing point detector. The linear regression equation was obtained. The reproduc- ibility was checked. The water content in raw milk was calculated according to the standard regression curve. E Result~ When the water content changed from 0 to 10%, the freezing point of raw milk increased linearly. As evidenced by the reproducibility test, the standard deviation and rela- tive standard deviation were less than 1%. The milk concentration obtained by detecting the freezing point of blind milk samples had an absolute er- ror of no more than 0.5%, compared with actual watering milk concentration. [ ConcluMonl Water content in raw milk can be determined by measur- ing freezing point, and this method is reliable and reproducible.

关键词： raw milk Freezing point Water content

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Evaluation of the Use of Sodium Thiocyanate and Sodium Percarbonate in the Activation of the Lactoperoxidase System in the Conservation of raw milk without Refrigeration in the Ecuadorian Tropics

引用

Food and Nutrition Sciences 2017年第5期8卷 526-534页

作者： Martin Campos-Vallejo Byron Puga-Torres Luis Núnez-Naranjo David De la Torre-Duque Samantha Morales-Arciniega Enrique Vayas Carchi Polytechnic University TulcánEcuador School of Engineering of Livestock Industries Chimborazo Polytechnic SchoolRiobambaEcuador School of Veterinary Medicine and Animal Science Central University of EcuadorQuitoEcuador Department of Experimental and Comparative Pathology School of Veterinary Medicine and Animal ScienceUniversity of Sao PauloSao PauloBrazil

milk production in Ecuador has enormous economic importance and large-, medium- and small-scale producers all participate in the market. There are multiple climatic regions, and dairy production is present in every one of them. High ambient temperatures in the Ecuadorian tropics represent a key challenge to the conservation of milk in the custody of smallholders. The objective of the present study was to evaluate the efficiency of the application of a chemical activator of the Lactoperoxidase System (LP-s) in the conservation of raw milk, at room temperature, in the Ecuadorian tropics. In the present study, sodium thiocyanate—0.36 g·L-1 of milk—and sodium percarbonate—1.36 g·L-1 of milk—as an activator of LP-s were used and the pH and microbiological characteristics (total coliforms, Staphylococcus aureus, total aerobes, molds and yeasts) of the milk at different storage times (0, 4 and 8 hours). The results obtained in the present study showed a significant difference between the two groups under study at 8 hours of storage at room temperature in all parameters (except yeasts where there was no growth in the two treatments), being relevant the significant decrease of the bacterial content. Thus the present study shows that the use of sodium thiocyanate and sodium percarbonate in the above described concentrations could be modulating the activation of LP-s that provides an efficient alternative for the conservation of the raw milk without refrigeration, improving the income for losses of the product and obtaining a raw material of good quality for sale or for further processing, mainly for small producers who do not have the economic resources to have refrigeration means for their product and who must transport their milk for considerably longer distances until they arrive at the collection centers or the processing plants for sale, thus showing that the method used in the present study is not only effective but also has a relatively low cost and easy applic

关键词： Lactoperoxidase System raw milk Conservation Coliforms

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Study on Factors Affecting Aerobial Plate Count in raw milk

引用

Agricultural Biotechnology 2023年第5期12卷 49-51页

作者： Luman HUO Yi LI Baiqin ZHENG Aijun LI Yanhui PAN Wang SONG Yunfei LIU Miaoyi ZHANG Xujian ZHENG Tangshan Food and Drug Comprehensive Testing Center Tangshan 063000China Tangshan Institute of Industrial Technology for Functional Agricultural Products Tangshan 063000China

[Objectives]This study was conducted to investigate the main factors affecting the aerobial plate count in raw milk.[Methods]Drinking water,medicated baths and raw milk under different storage and transportation conditions were detected for the values of aerobial plate count to analyze their effects on the aerobial plate count in raw milk.[Results]Disinfection of drinking water tanks could significantly reduce the aerobial plate count in *** use of medicated baths before and after milking could effectively reduce the aerobial plate count and had a significant bactericidal *** growth of microorganisms in raw milk stored below 4℃was relatively *** disinfecting drinking water tanks and disinfecting nipples before and after milking could reduce the aerobial plate count in the tanks and *** raw milk was extruded,the temperature should decrease to 0-4℃within 2 h,and the storage time should not exceed 48 h,which could effectively control the aerobial plate count in raw milk.[Conclusions]This study provides a reference for scientific control of the aerobial plate count in raw milk.

关键词： raw milk Aerobial plate count Drinking water Medicated bath Temperature

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：