Cowpea As New Source Of Protein

Victor Christian Kaharso began his doctoral research at TUM in October 2024, joining the research group Plant Proteins and Nutrition under the supervision of Prof. Ute Weisz. By that point, he was already familiar with his research focus - the cowpea (Vigna unguiculata). In its native Indonesia, it is a widely grown vegetable. It is mainly cultivated as animal feed, but has so far been used very little in the human diet. "I would like to explore the potential these beans hold for human nutrition through my work," says Victor. They might be an alternative to soybeans, which are currently imported mainly from China. Beyond Indonesia, the legumes also show great potential in Germany, where they can be cultivated locally and help build more resilient, sustainable food systems in the future.

"What makes cowpea exciting is its composition with about 20-25% protein and up to 60% carbohydrates, while being naturally low in fat", Victor explains. It also provides significant amounts of iron, magnesium, and B vitamins. Additionally, it is a heat loving and drought-tolerant legume - an important property in times of climate change. In his doctoral thesis, Victor focuses on isolating and characterizing proteins and other components of cowpea, exploring how they can be processed and used for food applications - from flours to plant-based products.

Although cowpeas have strong potential as a plant protein source, their use in food production remains limited due to the presence of antinutritional compounds. These compounds can reduce mineral absorption, inhibit digestive enzymes, and cause gastrointestinal discomfort, making cowpeas difficult to digest. As a result, their processing potential - particularly for industrial food use - has remained largely unexplored.

In his research, Victor addresses this challenge by applying germination as a natural and sustainable processing strategy. Germination is known not only to reduce anti-nutritional factors, but also to modify protein and starch structures, thereby improving functional properties such as solubility and gel formation. These changes are crucial for enabling the use of cowpea proteins in industrial food applications, including bakery products and beverages, while simultaneously enhancing their nutritional value.

To comprehensively explore the processing potential of cowpeas, the doctoral candidate conducts three interconnected studies. In the first study, he focuses on twelve cowpea varieties. "I am interested in how the different varieties differ in the composition of their constituents and in the structure in which these occur within the beans," he explains. In addition, he investigates which methods can be used to isolate and enrich proteins and starch. In doing so, he compares two fundamentally different processes: wet and dry fractionation. The analysis focuses on antinutritional compounds, protein solubility, and the structural organization of proteins and starch within the cowpea matrix.

Building on these results, the second study investigates germination as a strategy to reduce antinutritional factors in cowpeas. Victor examines how enzymatic activity activated during germination leads to the degradation of antinutritional compounds, thereby improving the nutritional quality of the legumes. In the third study, the focus shifts to the effects of germination-induced biochemical processes on the molecular structures of proteins and starch. Victor explores how these structural changes influence functional properties that are critical for food applications, such as solubility, gel formation, and suitability for industrial processing.

"My studies should provide both basic and practical knowledge of how cowpeas can be better utilized," says Victor. "I will help to promote them as a potential plant-based food ingredient for more resilient and sustainable food systems in tropical and temperate regions". For him, TUM is an inspiring place to do his research: "It connects agriculture, industry, and fundamental science - and allows research to go beyond the lab. "