The global plant-based “dairy” beverage market is valued at over $14 billion and continues to grow rapidly. Meanwhile, consumer demand for healthier products is increasing awareness of the importance of nutritional parity, including protein levels, whether with ‘regular’ dairy milk or high-fat drinks. increasingly popular proteins. Renske Janssen, Protein Technology Project Manager for NIZO, explains why success in this market requires more than just adding protein to the mix, and how a careful balance of components is essential.
René Floris: How do plant protein drinks compare to milk in terms of protein?
Renske Janssen: Regular dairy milk typically contains just over 3 grams of protein per 100 grams, while fortified protein dairy drinks can contain 20 grams or more of protein per serving, which is a big jump. These protein-rich drinks are traditionally used by specific groups such as athletes and the elderly to build muscle mass and help meet the recommended daily protein intake. However, the trend towards healthy products is attracting the interest of more types of consumers.
The world of vegetable proteins, on the other hand, is very diverse and each vegetable protein behaves in a different way. Some are already used to make milk substitutes that approach dairy milk protein levels: soy beverages, for example. But other plant-based drinks struggle to reach protein parity even with regular dairy milk. Rice and oat “milks”, for example, generally have low levels of protein and high amounts of carbohydrates.
Also, beyond protein quantity, you need to consider quality, which can include digestibility and essential amino acid composition. While dairy proteins contain all nine essential amino acids in the right amounts, plant proteins in many cases do not.
RF: Why is it difficult to add protein to a vegetable drink?
RJ: Vegetable proteins do not act in the same way as dairy proteins. They’re generally less soluble, for example, so just adding more protein can cause sedimentation in your drink. Larger insoluble particles can also give the drink a sandy or gritty mouthfeel, rather than the rich, creamy smoothness that consumers expect.
Plant material in general is also high in fiber, and the amount of fiber in a plant protein can vary, depending, for example, on whether it is a protein concentrate or an isolate. Generally, fiber is considered a “healthy” component, but it can have both positive and negative effects on your protein drink. You need to balance fiber with the type and amount of protein you use, to get the product characteristics you want.
RF: What are the benefits and challenges of increasing the fiber content of a beverage?
RJ: Fiber can act as a natural stabilizer, helping to hold protein in suspension and remove sediment. This can allow you to add more protein, while maintaining a smoother, creamier mouthfeel without added fat or sugar. On the other hand, too much fiber can make your product too thick to drink.
But balancing fiber is quite tricky, as fiber/protein interactions are very complex. In some cases, for example, adding fiber will increase protein solubility, in others it will decrease solubility. These interactions are not yet well understood: there is no table that says “if you combine fiber X and protein Y, you will get result Z”. This is something that researchers, including NIZO, are actively studying. We need to better understand the factors that play a role – such as charge – in order to simplify the selection of proteins, fibers, concentrations, etc.
RF: What role can the combination of plant proteins play in achieving protein parity?
RJ: Combining plant proteins can help you increase protein levels and balance amino acid levels to your desired composition. However, like fibre/protein interactions, protein/protein interactions can have surprisingly strong – and difficult to predict – effects. In some cases we have seen a combination of proteins affect solubility by up to 30%. This is another area where research is being conducted to better understand the mechanisms and identify the best combinations, but there is still a lot of work to be done.
RF: What techniques can be used to adapt plant protein processing to “next generation” applications?
RJ: Gentler extraction techniques can help maintain the protein’s native structure and increase solubility, for starters. Many plant proteins are currently extracted from by-products or side streams of oil or starch production. Although protein extraction is a priority, the initial process is optimized for starch and oil yield. However, I believe that protein will become an important “value added” product of processing. Ingredient manufacturers could thus benefit from a holistic approach: rethinking extraction to optimize protein, oil, starch, fibre, etc. for a maximum total value.
Optimization of fibre/protein interactions may also play a role. This includes selecting the best combinations of ingredients, but also changing processing conditions. Changing the pH, adding salt, and heating the final product (rather than protein concentrate or isolate) can all have an impact.
If the solubility is still not adequate, enzymatic treatments can be used to reduce the size of the protein by proteolysis. But you need balance: smaller proteins can mean smaller peptides (chains of amino acids), which can taste very bitter.
These types of techniques can provide a “roadmap” that can help increase protein levels in plant-based beverages. However, combining them with scientific knowledge and food production experience can help reduce “trial and error” and bring appealing next-generation beverages to market quickly and cost-effectively.
In our next article, we will look at fouling during food and ingredient processing.