Background

Natural food colorants obtained from plants are of growing interest, as they are safe and healthy and positively affect the color of the food; in addition, they may have further positive effects on its properties. Many studies have shown different methods of obtaining natural food colorants. To date, there are some review studies on natural food colorants, but there are no studies describing the process of the freeze-drying method and the pretreatments used.

Scope and approach

In this review, we describe the freeze-drying methods and pretreatments used in the measurement of the quality of the obtained food colorants. In addition, we review studies describing natural sources of colorants and examples of their applications in food. Future trends in the research related to natural food colorants have also been reviewed.

Key findings and conclusion

The most commonly used procedure for obtaining natural colorants consists of several basic steps: extraction, filtration, concentration, and freeze-drying. Freeze-drying is one method which can yield good quality product from whole or part plants, including without the addition of color stabilizers. Some interesting future techniques could be the use of industrial waste, fruit peels, or petals of various flowers in the production of natural pigments. The freeze-drying technique could be ideal for functional additives that combine several functions (color, fiber, minerals, and vitamins). The determination of antiseptic properties of natural colorants obtained by freeze-drying is also valuable.

中文翻译：

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通过冷冻干燥获得天然食用色素的方法的最新趋势

背景

从植物中获得的天然食用色素越来越受到关注，因为它们安全，健康并且对食品的颜色产生积极影响。此外，它们可能对其性能产生进一步的积极影响。许多研究表明获得天然食用色素的方法不同。迄今为止，已有一些关于天然食用色素的综述研究，但是还没有描述冷冻干燥方法的过程和所用预处理的研究。

范围和方法

在这篇综述中，我们描述了冷冻干燥的方法和预处理，用于测量获得的食品着色剂的质量。此外，我们回顾了描述色素天然来源及其在食品中应用实例的研究。还对与天然食用色素有关的研究的未来趋势进行了回顾。

主要发现和结论

获得天然色素的最常用方法包括几个基本步骤：提取，过滤，浓缩和冷冻干燥。冷冻干燥是一种可以从整个或部分植物中获得高质量产品的方法，包括不添加颜色稳定剂。未来一些有趣的技术可能是在天然色素的生产中使用工业废料，果皮或各种花朵的花瓣。对于结合了多种功能（颜色，纤维，矿物质和维生素）的功能性添加剂，冷冻干燥技术可能是理想的选择。通过冷冻干燥获得的天然着色剂的防腐性能的测定也是有价值的。