New Analytical Methods Aim to Better Protect Fruit Juices from Adulteration
An IGF project is developing a multi-method approach for four fruit matrices, intended to replace existing single-method approaches
For female consumers, fruit juice is synonymous with naturalness and quality. Products sold as fruit juice must not contain any added sugar—only the sugar that occurs naturally in the fruit. However, adulteration with foreign sugars is difficult to detect analytically because added syrups can mimic the natural sugar profile. An IGF project coordinated by FEI is therefore developing a new analytical method to detect foreign sugars in fruit juices and fruit juice concentrates. The goal is to reliably verify the authenticity of fruit juices.
For consumers, fruit juice is synonymous with naturalness and quality. What is labeled as fruit juice must not contain any added sugar—only the sugar that naturally comes from the fruit. For manufacturers, this authenticity is a key quality promise. At the same time, fruit juices and fruit juice concentrates are an economically sensitive product segment: they are traded primarily based on their sugar content, which is determined in the industry by the so-called Brix value. Particularly in the face of scarce raw materials, rising prices, and complex international trade flows, there can therefore be a significant incentive to illegally dilute juices or concentrates with other sugar sources (“foreign sugars”).
Analytically, such adulteration is difficult to detect. This is because the added syrups are selected or adjusted so that the primary sugars—glucose, fructose, and sucrose—match the natural sugar profile of the respective juice. A simple sugar analysis is therefore insufficient. Instead, methods such as isotope analysis or marker compounds—which occur in very small quantities in traditional sugar syrups—have been used to date. However, these methods have their limitations: Depending on the fruit matrix and the source of the foreign sugar, different methods are required, and some combinations are difficult or impossible to detect with certainty. Particularly problematic are new or previously little-studied sources of foreign sugars, such as syrups made from rice, corn, agave, or dates.
Research teams at the Technical University of Berlin and the University of Halle-Wittenberg are therefore developing a new strategy for detecting foreign sugars in fruit juices and fruit juice concentrates as part of an IGF project. The project, coordinated by the FEI, focuses on new degradation and transformation products such as disaccharides and oligosaccharides: These small sugar building blocks are produced during the manufacture of certain syrups or occur naturally in small quantities in them—and are therefore suitable as characteristic markers for detecting possible added foreign sugars.
The study will initially examine market-relevant and analytically challenging fruit matrices such as apple, orange, passion fruit, and strawberry. These will be compared with various potential sources of foreign sugars, including invert sugar syrups, starch syrups derived from rice and corn, and fruit sweeteners from agave and dates. The goal is to identify suitable marker substances and, based on these, develop a multi-method HPLC-MS/MS approach. This method is intended to be more sensitive, selective, and practical than previous approaches—and to reliably detect added sugars at levels as low as five percent in the future.
At the same time, a sample preparation strategy is being further developed to make the relevant trace components more detectable. Additionally, storage and model experiments are being conducted to rule out the possibility that potential marker substances could also arise from normal storage, heating, or processing. This is intended to prevent unadulterated products from being falsely rejected in the future.
The expected benefits for the German fruit juice industry are significant: The sector is dominated by small and medium-sized enterprises and relies on imported concentrates for many products. If adulteration cannot be reliably detected, there is a risk of economic losses, damage to reputation, and unfair competition against companies that use high-quality, unadulterated raw materials. A multi-method approach suitable for routine use can help commercial laboratories and manufacturers in the future to test raw materials and end products more reliably, reduce the costs of multiple individual analyses, and better ensure the authenticity of fruit juices. In this way, the project can make a significant contribution to strengthening consumer confidence in the authenticity of fruit juice.
Note: This article has been translated using a computer system without human intervention. LUMITOS offers these automatic translations to present a wider range of current news. Since this article has been translated with automatic translation, it is possible that it contains errors in vocabulary, syntax or grammar. The original article in German can be found here.
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Topic World Food Analytics
Food analysis methods enable us to investigate the quality, safety and composition of our food. Whether in the traceability of food, the detection of contaminants or the verification of nutritional information - food analytics plays a crucial role in our health and nutrition. Welcome to the exciting world of food analytics!
Topic World Food Analytics
Food analysis methods enable us to investigate the quality, safety and composition of our food. Whether in the traceability of food, the detection of contaminants or the verification of nutritional information - food analytics plays a crucial role in our health and nutrition. Welcome to the exciting world of food analytics!