Infrared Spectroscopy Emerges as Key Tool for Identifying Plant-Based Milk Alternatives

A recent study investigated how infrared (IR) spectroscopy, when combined with chemometric modeling, can serve as an inexpensive method for differentiating between popular plant-based milk substitutes. This study, which was published in the Journal of Food Composition and Analysis, responds to the current interest in plant-based milk substitutes, and how spectroscopy can be used to evaluate the authenticity, nutritional value, and composition of plant-based beverages (1).

Plant-based milk beverages are growing in popularity. The main three recognizable plant-based milk options include almond, soy, and oat (2). In 2010, only 1 in 5 households in the United States purchased plant-based milk (2). However, from 2014 to 2027, it is expected that the per capita revenue will increase approximately 127%, highlighting increased consumer interest in these beverages (2). A few main reasons are cited for this meteoric rise, including environmental considerations, health considerations, and marketing trends (2,3). However, as interest in these beverages increases, it becomes more important to monitor these milks for quality control purposes.

Plant-based milk options like almond soy and coconut emphasizing the trend of choosing vegan dairy alternatives for a more sustainable and health-focused lifestyle. | Image Credit: © CinimaticWorks - stock.adobe.com.

This study focused on analyzing almond, rice, oat, and soy drinks. These beverages are often chosen by individuals with lactose intolerance, milk protein allergies, or those following plant-based diets, fueling the need for reliable analytical methods to ensure quality and transparency (1).

As part of the experimental procedure, the research team used attenuated total reflectance FT-IR (ATR-FTIR) spectroscopy to collect collected detailed spectra of 40 beverage samples across a wide frequency range (4000–400 cm⁻¹) (1). Once the spectra were collected, the researchers then applied advanced statistical tools, including principal component analysis and hierarchical cluster analysis (HCA), to classify the drinks according to their unique compositional features (1).

The results from the study showed that the Amide I and II regions were important in differentiating between the beverage samples. Oat, rice, and soy drinks showed clear, consistent clustering patterns in the chemometric models, reflecting their stable and recognizable compositional signatures (1). However, almond beverages proved more challenging. Their significant variability in composition, which was sometimes because of the inclusion of high levels of rice or soy ingredients, resulted in less precise clustering (1). This variability mirrors nutritional information found on product labels, further validating the model’s accuracy (1).

The results from this study have numerous implications for the beverage industry. First, the plant-based food market is expanding rapidly. With increased consumer demand, it requires detection tools to be effective and rapid so more of these products can enter the market. Mislabeling or variability in formulations, such as almond drinks containing substantial amounts of rice or soy, can mislead consumers about nutritional content and have downstream economic effects (1).

By demonstrating the capacity of IR spectroscopy to classify products reliably, the study lays the foundation for future development of rapid quality-control protocols. PCA and HCA not only allowed for discrimination between different milk alternatives, but they also detected hidden variability within product categories (1). This represents a significant step forward compared to traditional analytical methods, which are often more labor-intensive and costly.

The method presented in this study can also be implemented in different laboratory and industrial settings. Because ATR-FTIR spectroscopy is portable, it could be applied not only in research laboratories, but also in routine industry testing environments, as well as in different application areas (1). The researchers believe this technology could help manufacturers verify ingredient authenticity, standardize quality, and meet regulatory requirements more efficiently and meet the expectations demanded by consumers (1).

As analytical technologies become more compact and user-friendly, it may one day be possible for retailers to verify the authenticity of plant-based beverages quickly and affordably (1).

References

1. Brito, A. L. B.; Duarte, C.; Fausto, R. Analysis of plant-based commercial milk substitutes using ATR-FTIR spectroscopy. J. Food Comp. Anal. 2025, 145, 107786. DOI: 10.1016/j.jfca.2025.107786
2. Chung, M. Milk to Mylk: The Growing Popularity of Plant-Based Milk Alternatives. The Pit Journal. Available at: https://pitjournal.unc.edu/2024/02/06/milk-to-mylk-the-growing-popularity-of-plant-based-milk-alternatives/ (accessed 2025-08-25).
3. ProVeg International, The Rise and Rise of Plant-based Milk: Why It’s Everywhere – and Here to Stay. ProVeg International. Available at: https://proveg.org/news/rise-and-rise-of-plant-based-milk/ (accessed 2025-08-25).