Spectroscopy-assisted quality control of high biological value fortified fruit juices: A joint Austria–Hungary project

Abstract

Growing consumer demand for value-added foods has accelerated the emergence of fortified products enriched with biologically active compounds. Fruit juices, commonly fortified with vitamins, minerals or plant-based extracts, represent a major segment of this market. However, the assurance of authenticity and compositional integrity of such products remains challenging, particularly in the absence of rapid, non-destructive analytical methods. The joint Austria–Hungary project aims to establish spectroscopy-assisted quality control tools for fortified fruit juices, combining near-infrared (NIR), infrared (IR) and Raman spectroscopy with advanced chemometrics. This multidisciplinary collaboration seeks to deliver reliable, non-invasive analytical solutions for industry, promoting consumer protection, reducing food fraud and supporting sustainable waste recycling through the valorisation of plant-based by-products.

Introduction

The diversification of consumer preferences has created a rapidly expanding niche for fortified foods and beverages. Among these, fruit juices enriched with biologically active compounds are particularly appealing, offering both convenience and perceived health benefits. Fortification typically involves the addition of vitamins, minerals, polyphenols or other plant-derived compounds that contribute to antioxidant capacity and overall nutritional value. These bioactive ingredients are often sourced from agricultural or processing by-products – such as fruit pomace or grape marc – representing an efficient approach to green waste reduction.

Despite these advantages, the fortification process introduces analytical and regulatory challenges. The strong influence of bioactive ingredients on organoleptic properties complicates quality control, while higher production costs increase the risk of adulteration and consumer deception. Conventional quality assessment techniques, such as chromatographic and wet-chemical methods, are accurate but often destructive, laborious and unsuitable for rapid on-line inspection. Therefore, there is an urgent need for fast, reliable and non-destructive tools capable of monitoring compositional integrity in fortified food products.

Motivation and background

This Austrian–Hungarian collaboration addresses these challenges by developing a spectroscopy-based analytical framework for fortified fruit juices (Figure 1). The approach builds on the complementary expertise of two leading institutions. The University of Innsbruck contributes long-standing experience in analytical chemistry, spectroscopy and chemometrics, while the Hungarian University of Agriculture and Life Sciences (MATE) brings extensive know-how in food technology, postharvest science and food quality control. MATE, one of the largest agricultural-focused higher education institutions in Central Europe, plays a central role in advancing digitalisation in the Hungarian food sector and in developing sustainable food production systems (Figure 2).

Figure 1.

Schematic representation of the spectroscopy-assisted quality-control workflow for fortified fruit juices.

Figure 2.

The Austrian–Hungarian collaboration team.

The partnership capitalises on these synergies to advance food analysis beyond conventional laboratory settings. By integrating vibrational spectroscopy and chemometrics, the project aims to generate a comprehensive analytical model capable of rapid and accurate quality assessment, strengthening the scientific collaboration between Austria and Hungary and contributing to the broader European effort for sustainable, transparent food production.

Project aims and methodology

The central objective of the project is the development of non-destructive, rapid analytical methods for monitoring the quality of fortified fruit juices. The project focuses on model systems prepared from common fruit juices – such as apple, berry and citrus varieties – fortified with plant extracts and bioactive compounds in different concentrations.

Spectroscopic measurements are carried out using a combination of benchtop and handheld instruments employing near- and mid-infrared as well as Raman spectroscopy. The multi-spectroscopic approach allows for comprehensive molecular fingerprinting of both liquid and semi-solid samples. Infrared spectra of liquid juices are recorded using Attenuated Total Reflectance (ATR) and transmission techniques, while Raman spectroscopy provides complementary vibrational information, particularly for aromatic and polyphenolic compounds.

Chemical reference analyses, including high-performance liquid chromatography (HPLC), gas chromatography–mass spectrometry (GC–MS) and antioxidant assays, are employed to establish accurate calibration datasets. The resulting spectroscopic and reference data are processed using advanced chemometric techniques, including principal component analysis (PCA), partial least squares regression (PLSR) and two-dimensional correlation spectroscopy (2D-COS). Data evaluation and model development are conducted collaboratively by the research teams at Innsbruck and MATE, ensuring methodological coherence and cross-validation between laboratories.

A strong emphasis is placed on evaluating the transferability of models between different devices and environments, ensuring that the developed analytical methods are robust and applicable in industrial settings. The ultimate goal is to provide reliable, cost-effective and portable quality control tools that can be directly implemented by juice producers for rapid, real-time assessment.

Expected outcomes

The expected outcome of the project is a validated, spectroscopic method capable of accurately assessing both the presence and concentration of bioactive additives in fortified fruit juices. The approach will also enable the estimation of broader quality parameters, such as antioxidant capacity, polyphenolic content, °Brix, pH and colour stability, through non-destructive means. The developed models are anticipated to support or even replace conventional laboratory-based quality assurance procedures, improving efficiency and reducing costs.

Beyond its analytical achievements, the project will significantly strengthen cross-border collaboration between Austria and Hungary. It will also contribute to the European objectives of circular economy and sustainable food systems by valorising plant-based by-products as fortifying agents and by enhancing digitalisation in food quality control. Dissemination of the project’s results is planned through peer-reviewed publications, conference presentations and industrial workshops, ensuring broad access to the developed methods and findings.

Related work

The methodology and collaborative approach reported by Lukacs et al. ¹ demonstrated the successful application of multiple NIR instruments to quantitatively evaluate grape seed and other polyphenolic extracts with high chemical similarity. The study highlighted the effectiveness of multi-instrument, chemometrics-based strategies for non-destructive quality assessment. Austria–Hungary project extends these approaches to fortified fruit juices, combining NIR, IR and Raman spectroscopy to enable rapid, non-invasive evaluation of bioactive compounds, compositional integrity and product authenticity. By leveraging the insights and strategies from the previous study, we aim to develop practical, robust and transferable analytical tools suitable for real-world food quality control.

Summary

This joint Innsbruck–Hungary project represents a step forward in modernising the quality control of fortified fruit juices through spectroscopy-assisted analysis. By integrating non-destructive vibrational spectroscopy with advanced chemometric modelling, the project bridges fundamental research and industrial application. The outcomes are expected to improve food transparency, protect consumers and foster sustainable production practices, while reinforcing scientific collaboration across borders (Figure 3).

Figure 3.

Cross-border cooperation between the University of Innsbruck (Austria) and MATE (Hungary) within the WTZ Austria–Hungary project.