天然香精及其鉴定方法介绍.docx

天然香精及其鉴定方法介绍多年来，崇尚自然、回归自然已成为世界性的不可抗拒的潮流。食品香料与香精的发展也无法逃离这一潮流。“天然的就是安全”或”天然的至少比人造的更安全“的观念根深蒂固。但是，从香料化学家角度来看，这是毫无根据的，一种天然香料与一种化学结构和纯度相同的合成香料相比，在毒理学上、营养学上和感官作用上毫无区别。一、 天然香精定义1.1欧盟有机产品中要求欧盟有机标准 EC834/2007889/2008、规定了天然调味剂（天然香精）才可以添加到有机产品中，在欧共体理事会 88/388/EEC中定义了天然食用香料或天然调味剂（人工调味料等同于天然调味料，但是加工调味料和烟熏调味料是不允许的）。不同于食品色素，包括天然的，天然调味剂在任何情况下都可以使用。食品色素是不允许食用的，作为肉和蛋壳的印章色素除外。1.2欧盟香精香料法规88/388/EEC中规定了天然香料的定义，如下：natural flavouring substances in the case of flavouring substances defined in Article 1 (2) (b) (i),Article 1 (2)(b) flavouring substance means a defined chemical substance with flavouring properties which is obtained:(i) by appropriate physical processes (including distillation and solvent extraction) or enzymatic or microbiological processes from material of vegetable or animal origin either in the raw state or after processing for human consumption by traditional food-preparation processes (including drying, torrefaction and fermentation),从天然原来经物理或发酵方法得到的香料称为天然食品香料。所谓物理方法是指：压榨、蒸馏、萃取、浓缩、层析。发酵方法包括酶催化、微生物发酵和植物组织培养（统称为生物技术法）1.3 美国FDA发布的法规中定义FDA 21 CFR CH.1 101.22 天然食品香料是指精油、油树脂、果汁精油或萃取物，水解蛋白质、蒸馏物（馏出物）或任何进焙烤加热或酶解的产物。它；含有来自辛香料、水果或果汁、蔬菜或蔬菜汁、可食酵母、香草、皮、花蕾、根、叶或类似的植物材料、肉类，海鲜、禽、蛋、奶制品或发酶产品的香味组分，它在食品中的功能是产生香味（风味），而不是为营养目的。1.4 食品香精香料国际组织IOFI在97年出版的“Guidelines on the Interpretation of the Term Natural”对天然香料的定义作了更明确的规范（见附录）。二、天然产品的鉴定方法目前，稳定同位素最早主要应用在地学领域，80年代后，美国、西德、日本、新西兰等国，特别是美国和西德对所有食品包括各种肉类、粮食、蔬菜、水果、饮料都进行了同位素分析。同位素溯源技术在食品安全领域主要用于鉴别食品成分掺假、 食品污染物来源、 追溯产品原产地以及判断动物饲料来源等方面。多集中在鉴别果汁加水、加糖分析，葡萄酒中加入劣质酒、甜菜糖、蔗糖等的分析以及蜂蜜加糖分析等方面。此外 ,还可鉴别不同植物混合油、 高价值食用醋中加入廉价醋酸等掺假分析。美国克鲁格和里斯曼的实验室自1977年以来每年都做3000多个食品同位素样品，目的是监测市场上食品的纯度、真假和来源。由于方法对头，工作得力、得到国家标准局、商检局的认可，并被国家列为例行检测方法。他们主要检测了市场上大量的蜂蜜、桔汁、苹果酱、葡萄酒等食品。最初检测证明，市场上假冒食品很普遍。经过一段时间治理整顿，这种假冒产品迅速减少。美国FEMA建立了同位素研究委员会（FEMA-ISC），它与美国佐治亚大学应用同位素研究中心进行广泛合作，并向该中心提供资金援助，对一系列食品香料的天然度进行测定，为他们建立了13C及13C/12C的范围，这些香料中主要有苯甲醛、肉桂醛、茴脑、水杨酸甲酯及各种脂肪酸酯类等。碳同位素分析技术用于各种香料的分析也很见效。天然香兰素十分昂贵，而合成香兰素化学成分和天然香兰素完全相同，很便宜。他们大多用木质素合成，也有用丁香油或煤焦油合成的。采自世界各地的香兰素13C值多在-16.8和-20.4，而合成的香兰素多在-16.8以下，因此，有人将天然和合成香兰素的界定值定为-21，低于该值就认为加入了合成物质。附录1February 29, 2012 General Assembly approved V1.3 30 13. GUIDELINES ON THE IOFI INTERPRETATION OF THE TERM “NATURAL” 13.1 Introduction The purpose of these Guidelines is to provide guidance on the IOFI interpretation of the term “natural” as used in the IOFI terminology (Chapter 3-Definitions) and the Codex Alimentarius Guidelines for the Use of Flavourings (CAC/GL 66-2008 Annex III). The application of the Code of Practice, including its Annexes does not relieve individual manufacturers from the obligation to comply with all national or international regulations that pertain to their operations. These regulations, including official guidelines and rulings and officially condoned practices, will take precedence over these Guidelines. In those countries where corresponding specific legislation are not in force, the Code of Practice should serve as a best practices resource. 13.2 Raw Materials Raw materials, which are used as a source for natural flavourings, are materials of animal, vegetable or microbiological origin. Sources for natural flavouring complexes and natural flavouring substances are the essential oils, oleoresins, extractives, distillates, or products of roasting, heating or enzymatic transformations of spices, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb, bark, bud, root, leaf or similar plant material, meat, seafood, poultry, eggs and other animal products, dairy products, or fermentation products thereof. 13.3 Isolation Techniques All physical processes may be used for the isolation of natural flavouring complexes or natural flavouring substances. pH adjustment may be used for the isolation of acidic and basic materials. 13.4 Biochemical Processes for Natural Flavouring Complexes, Concentrates and Natural Flavouring Substances 13.4.1 Organisms and Enzymes Biological entities capable of self-replication or resulting from biological reproduction such as bacteria, yeast, fungi, plants and animals, in whole or in part, and enzymes derived thereof, are permitted for producing natural flavourings. February 29, 2012 General Assembly approved V1.3 31 13.4.2 Substrates If the substrates used to produce natural flavourings by biochemical processes are natural, as defined in the other sections of this document, then the end products isolated from such processes are considered natural flavourings. 13.4.3 Co-factors, Nutrients, Vitamins, Hormones and pH-adjusting Agents Materials added to the substrate necessary for the growth and function of the organism(s) such as co-factors, minerals, nutrients, vitamins, hormones, pH adjusting agents and electromagnetic radiation are not restricted in origin, but they may not exceed the levels required for the purpose of maintaining the growth and function of the organism(s) or parts thereof. 13.4.4 Carrier System The carrier system may be aqueous or non-aqueous. Natural substrates can be used as carriers. Non-natural carriers can only be used if they do not react irreversibly and do not serve as a substrate. Carriers may remain in the final mixture provided they are permitted as carrier solvents for natural flavourings. 13.5 Other Processes for Natural Flavouring Complexes and Natural Flavouring Substances Processing conditions are permissible if they are used in food processing or in-home preparation, or occur in nature. See examples in Table 1. Table 1. Examples of food preparation processes Absorption