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.     

离子色谱法检测腐竹、粉丝中的乌洛托品

建立了腐竹和粉丝中违禁添加剂乌洛托品的离子色谱检测法。 实验优化了萃取溶剂和萃取条件。 结果表明,乌洛托品在0.10~4.0 μg/g范围内线性关系良好,相关系数为0.99937。 方法对腐竹和粉丝的检出限为0.079 μg/g。 腐竹和粉丝的加标回收率为86%~96%,相对标准偏差为1.9%。 该方法简便,快速,可用于腐竹和粉丝中乌洛托品的检测。     

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.     

改进的QuEChERS方法结合液相色谱-串联质谱法测定腐竹和豆干中的二甲基黄和二乙基黄

建立了基于改进的QuEChERS方法结合液相色谱-串联质谱测定腐竹和豆干中二甲基黄和二乙基黄的方法。在2.0 g腐竹和豆干样品中加入5 mL水浸泡,然后加入10 mL乙腈提取,加入1.0 g NaCl、2.0 g无水硫酸镁进行液液分离;取1 mL提取液经50 mg N-丙基二乙胺分散固相萃取净化,经液相色谱分离、质谱测定,外标法定量。二甲基黄在添加水平为0.3、1和10 μg/kg时,方法的回收率为73.5%~84.5%;二乙基黄在添加水平为0.1、1和10 μg/kg时,方法的回收率为70.5%~81.2%;方法的相对标准偏差小于11%。二甲基黄的检出限和定量限分别为0.1 μg/kg和0.3 μg/kg,二乙基黄的检出限和定量限分别为0.05 μg/kg和0.1 μg/kg。该方法可以用于腐竹、豆干中二甲基黄和二乙基黄的快速筛查和定量分析。     

Analysis of Cannabinoids and Metabolites in Dried Urine Spots (DUS)

Dried urine spots (DUS) represent a potential alternative sample storage for forensic toxicological analysis. The aim of the current study was to develop and validate a liquid chromatographic tandem mass spectrometric procedure for the detection and quantitative determination of cannabinoids and metabolites in DUS. A two-step extraction was performed on DUS and urine samples. An LC-MS/MS system was operated in multiple reaction monitoring and positive polarization mode. The method was checked for sensitivity, specificity, linearity, accuracy, precision, recovery, matrix effects and carryover. The method was applied to 70 urine samples collected from healthy volunteers and drug addicts undergoing withdrawal treatment. The method was successfully developed for DUS. LODs lower than 2.0 ng/mL were obtained for all the monitored substances. All the validation parameters fulfilled the acceptance criteria either for DUS or urine. Among the real samples, 45 cases provided positive results for at least one compound. A good quali-quantitative agreement was obtained between DUS and urine. A good stability of THC, THCCOOH and THCCOOH-gluc was observed after a 24 h storage, in contrast to previously published results. DUS seems to provide a good alternative storage condition for urine that should be checked for the presence of cannabinoids and metabolites.     

自制双层固相萃取柱在新会陈皮及其制品中11种有机磷农药测定中的应用

以自制改性多壁碳纳米管（MWNTs）和N-丙基乙二胺（PSA）填料分层填装的双层固相萃取柱为净化柱,建立了测定陈皮及其制品中11种有机磷农药残留的分析方法。样品经乙酸乙酯提取、离心后,固相萃取柱净化,净化液经Agilent RTS-1701毛细管柱分离,火焰光度检测器检测,外标法定量。考察了填料类型、填料用量、洗脱方式等因素对提取效率的影响。在优化条件下,11种有机磷农药检测的线性范围为0.020~1.0 mg/L,相关系数为0.9990~0.9998,检出限为3.5~9.6 μ g/kg。样品在10、25、100 μg/kg 3种水平下的加标回收率为50.8%~109%,相对标准偏差为2.7%~8.5%。该法准确度和灵敏度高、操作简单、快速,检出限能满足对有机磷农药残留的限量要求。自制固相萃取柱可降低成本,值得推广应用。     

Analysis of thermolabile residual solvents in a spray dried dispersion using static headspace gas chromatography

In this study, we discuss the development of a static headspace gas chromatography method for the analysis of residual acetone as well as its enriched impurities including mesityl oxide and diacetone alcohol, in a spray dried dispersion. The major challenges include the instability of mesityl oxide and diacetone alcohol at high temperature and peak tailing of diacetone alcohol. It was found that the headspace oven temperature has to be controlled to 150°C or below to prevent degradation beyond an acceptable level (< 1%). The peak tailing of diacetone alcohol was attributed to the “Phase Soaking” effect due to excessive diluent, which may condense and temporarily modify the stationary phase. The peak shape of diacetone alcohol is dependent on the column loading capacity and the peak area of N‐methyl pyrrolidone, the solvent that elutes after diacetone alcohol. The headspace oven temperature was set at 140°C, where the highest response ratio of diacetone alcohol/N‐methyl pyrrolidone at 1.46 and thus the best sensitivity was obtained. The calculated quantitation limits were 1 ppm for acetone, 3 ppm for mesityl oxide and 31 ppm for diacetone alcohol. The method successfully passed validation criteria for specificity, linearity, accuracy, and precision.