Using Bioelements Isotope Ratios and Fatty Acid Composition to Deduce Beef Origin and Zebu Feeding Regime in Cameroon

The purpose of this study was to address the lack of knowledge regarding the stable isotopic composition of beef from zebu cattle reared in tropical Africa. Sixty beef carcasses belonging to the most common zebu breeds (Goudali, white Fulani, and red Mbororo) were selected and classified according to their subcutaneous fat color (white, cream or yellow). The stable isotope ratios of five bioelements—H, O, C, N, and S—in muscle fractions and the fatty acids composition were analyzed. Zebu meat from Cameroon shows peculiar δ¹³C values, related to the almost exclusive intake of grazed tropical grasses with photosynthetic cycle C4. It also shows δ²H and δ¹⁸O values higher than those reported in other areas of the world and correlated with the isotopic composition of animal drinking water. The white subcutaneous fat (“white type”) zebu showed higher δ²H and lower δ¹³C than the “yellow type”, that is correlated with a higher content of polyunsaturated fatty acid (PUFA) and a lower amount of saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA). Multielement analysis seems to provide promising results for tracing the regional origin of Cameroon beef and some aspects of the livestock system, such as the nutritional status of the animals.     

超高效液相色谱-串联质谱法快速测定猪尿液中30种不同种类“瘦肉精”药物残留

建立了超高效液相色谱-串联质谱快速简单地同时测定猪尿液中30种不同种类“瘦肉精”药物(赛庚啶、可乐定及28种β-受体激动剂类)残留的方法.对液相色谱分离条件、MS/MS检测参数及样品前处理方式进行了优化.试样经5000 r/min离心5 min后直接经MCX柱净化,分别用3 mL水和3 mL甲醇淋洗,5％氨化甲醇进行洗脱,N2吹干后以流动相进行复溶,UPLC-MS/MS进行测定.结果表明,30种药物可在5.0 min内有效分离;各药物在0.1 ～ 10μg/L范围内呈良好的线性关系,相关系数均大于0.992;方法的检出限为0.1 μg/L,定量限为0.3 μg/L.在3个浓度水平下的平均回收率为67.6％ ～ 103.2％,日内、日间相对标准偏差分别为2.8％ ～ 16.8％和2.6％ ～15.8％.     

高效液相色谱法测定虾肉及虾制品中吲哚含量

称取适量鲜虾肉或虾肉干,用乙腈(20mL)提取2次,离心分离后取其上清液,用乙腈定容至50.0mL,供高效液相色谱分析。加入2-甲基吲哚作为内标,所用色谱柱为Hedera ODS-2柱,流动相为乙腈-水(65+35)混合液,用荧光检测器检测(λex=270nm,λem=340nm)洗脱液中吲哚含量。标准曲线的线性范围在200μg·L-1以内,方法的测定下限(10S/N)为125μg·kg-1。以空白样品作基体,用标准加入法进行回收试验,测得回收率在90.1%~104%之间,测定值的相对标准偏差(n=6)在1.9%~5.2%之间。     

热辅助解吸-介质阻挡放电离子化质谱快速检测磺胺类药物

磺胺类药物在家禽养殖行业中的滥用是一个极其严重的问题。该文采用一种热辅助解吸介质阻挡放电离子化质谱技术（HAD-DBDI-MS）,通过对其加热温度等参数的优化,建立了对磺胺吡啶、磺胺间甲氧嘧啶、磺胺喹噁啉、磺胺胍及磺胺甲噁唑等磺胺类药物的快速检测方法,并通过二级质谱进行结构鉴定;与单独使用DBDI-MS相比,HAD-DBDI-MS的检出限降低了1~2个数量级。对鸡肉模拟加标进行了直接快速检测应用,实现了鸡肉中模拟添加磺胺吡啶的检出;通过在加热时引入甲醇辅助挥发,实现了对饲料模拟加标压片样品中磺胺胍、磺胺甲噁唑的检出。结果表明,HAD-DBDI-MS为禽类肉制品和饲料中磺胺类药物的快速检测提供了一种新的方法。     

智能感官分析技术结合传统感官评价对细点圆趾蟹蟹肉制品品质特性研究

采用智能感官分析技术结合传统感官评价,研究了细点圆趾蟹蟹肉、细点圆趾蟹重组蟹肉、仿蟹肉块和仿蟹肉棒的感官品质。4类均为低脂类、可放心食用的食品。用电子舌技术与主成分分析法对4类蟹肉样品进行了区分和识别,用质构仪检测了4类样品的适口性（包括硬度、弹性、黏结性、胶性、咀嚼性和回复性）。结果表明,仿蟹肉制品与纯蟹肉在味道上存在明显差异,纯蟹肉较仿蟹肉制品具有更强的鲜味回味,但苦味、涩味和苦味回味相对较高;蛋白质类添加剂（TG酶）有利于提高纯蟹肉的感官品质,尤其可大幅度改良口感和质地,全质构分析测定结果与人的感官评价结果一致性较高。     

凝胶渗透色谱净化/气相色谱-负化学源质谱法测定肉及肉制品中氯化松节油残留

采用凝胶渗透色谱(GPC)净化技术,建立了猪肉、牛肉、羊肉、鸡肉4种肉类及腊肉和肉松2种肉制品中氯化松节油残留量的气相色谱-负化学源质谱(GC-NCI/MS)测定方法。样品经正己烷涡旋振荡提取,乙酸乙酯-环己烷(1∶1)为流动相进行凝胶渗透色谱净化,采用选择离子监测模式(SIM)测定,外标法定量。氯化松节油在0.01～2.0 mg/L质量浓度范围内呈良好线性,相关系数(r)为0.999 7。方法定量下限为10μg/kg。对上述6种基质,分别在10.0～50.0μg/kg之间进行4个不同水平的加标回收实验,加标回收率为80%～98%,相对标准偏差(RSD,n=8)为2.1%～8.7%。该方法适用于多种肉类及肉制品中氯化松节油残留量的确证及定量检测。     

Changing attitudes to irradiation throughout the food chain

Recent studies of consumer attitudes in the United States indicate an increased willingness to purchase irradiated food in order to have a safer product. The reasons for the change in attitude are discussed. Basic consumer buying habits are considered and how these fit in with marketing irradiated food. Food retailers, restaurants and producers have attitudes of their own, and these can sometimes be the most difficult to change. The key to this puzzle can be found in their basic motivations, including the fear of activists. Recommendations are made as to how this information can be used to promote the development of food irradiation.     

虹膜识别在基于物联网的肉类食品溯源中的研究

依托物联网平台,构建"从源头到餐桌"的信息溯源体系是肉类食品安全当前亟待解决的重要问题.大型动物个体识别在肉类食品溯源系统中起着非常关键的作用.鉴于传统动物识别方法对于个体溯源准确度不高,将大型动物的虹膜特征提取与编码作为个体鉴别的关键技术引入溯源体系中.将虹膜编码信息与饲养、屠宰加工、配送和分割销售信息结合起来并转化成电子编码储存于RFID标签,以实现大型动物的活体与分割肉块的信息衔接.方法能有效地解决传统动物识别系统中的欺骗及设备功能异常现象等问题,达到肉类食品信息查询和出现安全问题后个体溯源的目的.     

超高效液相色谱-串联质谱法同时测定粮食及肉制品中的24种工业染料

建立了测定粮食及肉制品中24种禁用工业染料的超高效液相色谱-串联质谱法。样品经甲醇、乙腈提取后,过WAX固相萃取柱净化。采用ACQUITY UPLC BEH C18分析柱分离,以10 mmol/L乙酸铵-0.2%甲酸水溶液和甲醇-乙腈(7:3, v/v)为流动相梯度洗脱,多反应监测(MRM)模式测定。24种染料的相关系数R²均大于0.99,回收率在61%~116%之间,方法的精密度(RSD, n=6)小于13%,定量限在0.1~4.0 μg/kg。该方法灵敏度高,操作简单、高效,适合于粮食及肉制品中24种禁用工业染料的同时定量及确证分析。     

Biochemical and Functional Characterization of Kidney Bean Protein Alcalase-Hydrolysates and Their Preservative Action on Stored Chicken Meat

A new preservation approach is presented in this article to prolong the lifetime of raw chicken meat and enhance its quality at 4 °C via coating with highly soluble kidney bean protein hydrolysate. The hydrolysates of the black, red, and white kidney protein (BKH, RKH, and WKH) were obtained after 30 min enzymatic hydrolysis with Alcalase (E/S ratio of 1:100, hydrolysis degree 25–29%). The different phaseolin subunits (8S) appeared in SDS-PAGE in 35–45 kD molecular weight range while vicilin appeared in the molecular weight range of 55–75 kD. The kidney bean protein hydrolysates have considerable antioxidant activity as evidenced by the DPPH-scavenging activity and β-carotine-linolenic assay, as well as antimicrobial activity evaluated by disc diffusion assay. BKH followed by RKH (800 µg/mL) significantly (p ≤ 0.05) scavenged 95, 91% of DPPH and inhibited 82–88% of linoleic oxidation. The three studied hydrolysates significantly inhibited the growth of bacteria, yeast, and fungi, where BKH was the most performing. Kidney bean protein hydrolysates could shield the chicken meat because of their amphoteric nature and many functional properties (water and oil-absorbing capacity and foaming stability). The quality of chicken meat was assessed by tracing the fluctuations in the chemical parameters (pH, met-myoglobin, lipid oxidation, and TVBN), bacterial load (total bacterial count, and psychrophilic count), color parameters and sensorial traits during cold preservation (4 °C). The hydrolysates (800 µg/g) significantly p ≤ 0.05 reduced the increment in meat pH and TVBN values, inhibited 59–70% of lipid oxidation as compared to control during 30 days of cold storage via eliminating 50% of bacterial load and maintained secured storage for 30 days. RKH and WKH significantly (p ≤ 0.05) enhanced L*, a* values, thus augmented the meat whiteness and redness, while, BKH increased b* values, declining all color parameters during meat storage. RKH and WKH (800 µg/g) (p ≤ 0.05) maintained 50–71% and 69–75% of meat color and odor, respectively, increased the meat juiciness after 30 days of cold storage. BKH, RKH and WKH can be safely incorporated into novel foods.