近红外光谱技术在茶叶质量安全领域的应用

随着茶叶产量的不断提升,茶叶产品质量安全问题日益受到关注,目前普遍使用的传统的化学检测和感官审评方法,无法实现在茶叶生产及流通过程中对茶叶品质进行实时监控。近红外光谱分析作为一种新兴技术,具有样品无损耗、结果客观以及快速简便等优点,能满足茶叶产品实时检测的需求。本文在概述近红外光谱分析技术的基础上,对国内外近红外光谱分析技术在茶叶品质分析、等级确定、种类识别和产地溯源和真伪鉴别等方面的研究进展进行了综述。分析了近红外光谱分析技术在推广应用中存在的问题,指出近红外作为一种二级分析方法,其模型适用范围具有局限性,同时对其灵敏度以及成本作出客观评价;对今后的发展及研究方向进行了展望,以期近红外光谱分析技术能够更好地应用于茶叶领域。     

Zero Risk Does Not Exist: Lessons Learned from Microbial Risk Assessment Related to Use of Water and Safety of Fresh Produce

Risk assessments related to use of water and safety of fresh produce originate from both water and food microbiology studies. Although the set‐up and methodology of risk assessment in these 2 disciplines may differ, analysis of the current literature reveals some common outcomes. Most of these studies from the water perspective focus on enteric virus risks, largely because of their anticipated high concentrations in untreated wastewater and their resistance to common wastewater treatments. Risk assessment studies from the food perspective, instead, focus mainly on bacterial pathogens such as Salmonella and pathogenic Escherichia coli. Few site‐specific data points were available for most of these microbial risk assessments, meaning that many assumptions were necessary, which are repeated in many studies. Specific parameters lacking hard data included rates of pathogen transfer from irrigation water to crops, pathogen penetration, and survival in or on food crops. Data on these factors have been investigated over the last decade and this should improve the reliability of future microbial risk estimates. However, the sheer number of different foodstuffs and pathogens, combined with water sources and irrigation practices, means that developing risk models that can span the breadth of fresh produce safety will be a considerable challenge. The new approach using microbial risk assessment is objective and evidence‐based and leads to more flexibility and enables more tailored risk management practices and guidelines. Drawbacks are, however, capacity and knowledge to perform the microbial risk assessment and the need for data and preferably data of the specific region.     

服饰中的色彩视错觉分析

以色彩视错觉在服装中的应用为核心,以着装要素为出发点,建立一种色彩视觉差的定量分析表,并从色彩心理学的角度阐述各影响因素,为服装的感觉、知觉进行科学的分析。     

储良龙眼挥发性成分的定量- 保留指数分析

基于拓扑理论及MATLAB程序计算41种龙眼挥发性成分的分子连接性指数(mXtv)和电性距离矢量(Mt)。采用最佳变量子集回归方法,建立龙眼挥发性成分的保留指数(BZ)与mXtv、Mt的定量结构-保留相关的五元回归方程,传统判定系数、逐一剔除法交叉验证系数依次为0.981、0.976。用Jackknife法检验模型的稳健性,其传统判定系数在0.975～0.986之间。该模型具有高度稳健性与良好的预测能力,并能较好解释有机组分保留指数的递变规律。     

Potential for improvement in yeast nutrition in raw whole grain sorghum and maize lager brewing and bioethanol production through grain genetic modification and phytase treatment

Brewing and bioethanol production with raw grain and exogenous enzymes produces wort with satisfactory hot water extract (HWE). However, the free amino nitrogen (FAN) and mineral content can be too low, owing to low protein digestibility (PD) and phytate–mineral chelation, respectively. This study evaluated the potential for improvement in yeast nutrition in raw whole sorghum and maize brewing and bioethanol production by genetic modification (GM) of sorghum to improve PD and reduce phytate content, and by treatment with exogenous phytase. While phytase addition decreased sorghum spent grain phytate content (88%) and content of minerals (17 to 59%; i.e. increased wort mineral content), it did not affect maize phytate spent grain mineral content or HWE significantly. However, phytase addition did increase maize wort FAN (20%), sorghum HWE (2.8 percentage points) and wort FAN (23%). GM sorghum gave reduced spent grain mineral contents (11–38%), increased HWE (5.5 percentage points) and wort FAN (71%). Hence, genetic modification of sorghum to improve PD and reduce phytate content has considerable potential in raw grain brewing and bioethanol production to improve yeast nutrition. Copyright © 2012 The Institute of Brewing & Distilling     

2017—2022年已备案国产保健食品信息统计分析与思考

目的 对2017年7月至2022年4月已备案的国产保健食品进行统计分析,为生产企业的保健食品研发及备案工作提供参考,为监管部门制定相关法规提供数据支持。方法 采集了国家市场监督管理总局特殊食品信息查询平台及各省（自治区、直辖市）市场监督管理部门公布的保健食品备案信息9 835件,分别从备案数量、备案地区、剂型、产品类型、保健功能及原料配伍等方面进行了分析。结果 我国保健食品备案数量从2017年开始总体呈增长趋势,但备案地区分布较不均衡;从剂型上看,片剂占50%以上,胶囊类产品约占30%;8 950件营养素补充剂中,补充单一营养素的产品最多,占43.7%(3 911/8 950)。已有885件功能性保健食品完成备案,以螺旋藻为原料的产品备案数量较少,其他四种原料备案产品数量均在150种以上。结论 国产保健食品备案工作开展以来,已备案产品数量已达近万件。建议有关监管部门不断完善现有法规,以保证我国保健食品的备案工作平稳、快速推进。生产企业应根据人们的健康需求及相关法规,做好配方研发及产品备案工作,在为企业自身带来经济利益的同时,为推动“健康中国”建设助力。     

我国食品微生物定量风险评估的研究进展

近10余年来,我国政府重视食品安全并逐渐加强风险分析体系的构建和实施。根据历年来国家卫生与计生委的统计数据,表明由致病微生物导致的食物中毒发病率一直高于其他危害。食源性致病菌引起的食品安全风险是全球性问题,发展中国家面临的情况更为严峻,因此加强我国微生物定量风险评估以减少与发达国家的差距,从国家层面上势在必行。特别是2009年我国颁布实施《食品安全法》和2011年成立国家食品安全风险评估中心（ChinaNational Center for Food Safety Risk Assessment,CFSA）以来,已有不少针对国内具体食品致病菌情况开展的食品微生物定量风险评估（quantitative microbial risk assessment,QMRA）研究。本文对2000年至今我国已开展的QMRA研究,包括涉及的食品、致病菌、微生物预测模型、剂量-效应模型等进行详细综述。同时指出我国开展QMRA面临的技术性难题及解决方法,并对采用QMRA结果用于构建危害分析与关键控制点（Hazard Analysis and CriticalControl Point,HACCP）和食品安全目标（ food safety objective,FSO）以及执行目标（performance objective,PO）的应用前景进行探讨。建议加强风险评估与风险管理的互动交流、进一步完善风险监测、微生物限量制定和国际合作,在完善实施指南的基础上针对我国具体国情开展更多具有科学性和系统性的QMRA研究。     

野生食用菌中矿物质和重金属研究概况

食用菌(Edible mushroom)由于其独特的风味和鲜嫩的肉质,在很多国家都被誉为佳肴。野生食用菌富含多糖、维生素和矿物质等,具有抗肿瘤和调节免疫等多种功能,是世界公认的不可多得的高营养兼药膳的\