Development of protein enriched soft drinks

In recent years there has been growing interest in alcohol-free drinks having functional benefits such as energy drinks, sports drinks, and wellness drinks. There is particular interest in products having a high protein content and containing natural plant-based ingredients. Plant-based raw material do, however, often contain antinutritive substances that can reduce the use of the valuable proteins. In addition, plant proteins tend to aggregate in the acidic media of soft drinks due to their small net charge and would remain undissolved as a sediment in the drink. There is hence a gap for plant protein based soft drinks in the current marketplace.

Manufacturing process for plant protein enriched drinks

A previous research project already successfully demonstrated that a protein-rich ingredient for drinks can be manufactured from the acid-soluble globulin fraction of lupines and an accompanying enzyme-rich barley malt using a combined mashing and fermentation process. The antinutritive substances were successfully reduced and various protein-enriched drinks with appealing sensory properties were manufactured.

A technical hurdle for implementation in practice was, however, the low amount of acid-soluble protein in the lupine seeds. Although the necessary processes for concentration are available, these are costly for the overall process. The process costs could be considerably reduced by increasing the amount of acid-soluble protein and by avoiding time-consuming protein isolation and costly membrane processes. This would enable SMEs to manufacture the innovative, protein-enriched drinks.

New low-cost manufacturing method

The current research project is using pregerminated lupine seeds due to the fact that endogenous enzymes which increase the protein solubility are activated during germination. Subsequently the lupine seeds are subjected to microbial fermentation in order to metabolize or neutralize undesired substances. Extra enzyme-rich fruit and vegetable juices are added in order to develop an innovative protein-rich base material for soft drinks with high nutri-physiological value. Also, the adsorptive property of calcium is utilized in order to bind and remove any unpalatable fatty acids that are released.

At the end of the project the knowledge gained from the work on lupines should be able to be transferred to other legumes such as peas and soy beans. This should enable the range of tasty protein-enriched drinks to be enormously expanded.