In recent years, plant-based proteins have gained greatly in popularity and are recognised for their ability to promote a food supply system that is more sustainable and in line with the need for human, animal, and environmental health. This is closely linked to the awareness among consumers of climate change and the possible repercussions of their food consumption habits. This topic is particularly important from a demographic viewpoint: according to the United Nations, global population will reach 10.4 billion people by the end of the century, placing enormous challenges in ensuring supply of safe, nutritious, and sustainable food for all. In this scenario, the global agri-food system is called on to come up with innovative solutions with a low environmental impact.
As one third of greenhouse gas emissions come from the food industry, in particular from products of animal origin, there is much focus on new proteins, driven also by consumer demand for healthier and more environmentally friendly food products. Indeed, plant-based proteins offer a real opportunity for reducing the carbon footprint of the food industry and promoting a more balanced diet.
In spite of this growing interest, however, plant-based proteins still face major difficulties associated with consumer acceptance, especially with regard to the taste and texture of plant-based products. According to a study published in the scientific paper “Oral Astringency in Plant Proteins: An Underestimated Issue in Formulating Next-Generation Plant-Based Foods” (Sarkar A., Annu. Rev. Food Sci. Technol. 2024. 15:103–23), one of the major problems regards astringency. This characteristic, which is typical of plant-based proteins, has a negative impact on our sensory perception of a product, which compromises its texture and taste.
Astringency, which is perceived as a feeling of dryness or roughness in the mouth, may reduce the appeal of plant-based products. This aspect is crucial, given that taste is the leading factor in consumer purchasing decisions. The statistics of the Good Food Institute show that the penetration rate of meat alternatives is 15%, with a repurchase rate of 62%. And even though the number of initial buyers is still limited, those who try these products tend to repeat their purchases. To extend the target to flexitarian consumers – individuals looking to reduce their meat intake without eliminating it – improving the taste and palatability of these products is imperative.
According to the above study, plant-based proteins and derived products are often described by consumers using terms like “astringent” and “dry”, and aftertastes ranging from bitter to herbaceous, from leguminous to earthy, and even soapy or metallic. Such descriptions illustrate the complexity of the sensory issues surrounding these products. But where does this astringency come from?
To date, scientific research has focused greatly on the study of volatile compounds, such as alcohols, aldehydes, and ketones, that are typical of certain plant-based protein ingredients and are often responsible for the typical ‘legume’ aftertaste. Similarly, the origin of bitterness, often linked to secondary metabolites, has been the focus of research for years. The same attention has not been reserved to the topic of astringency, despite the known correlation with the presence of polyphenols in plant-based proteins. As explained in the study, astringency is a sensation triggered by specific interactions between polyphenols and salivary proteins, producing a feeling of dryness, contraction, and a granular or powdery texture in the mouth and on the tongue.
Research and technological innovation to overcome sensory challenges
To tackle these problems and improve the sensory quality of plant-based proteins, the paper proposes several innovative strategies, which can be broken down into the following three categories:
While these strategies provide substantial improvements, it is crucial to take into account the possible environmental and nutritional sustainability implications of the product. The addition of ingredients to improve texture and taste, for example, might make products less sustainable due to an increased number of steps in production, or by adding ingredients that make the label less appealing or negatively impact the nutritional profile. Similarly, some technological solutions require significant investments, which could influence the final costs for consumers. Research must continue to take an even closer look at plant-based proteins and the origin of compounds that produce unpleasant sensory notes, as a means to improve these ingredients and make them more widely available on the market and, in turn, increase their popularity among consumers.