The offer of non-animal food is continuously growing. The most important ingredients of these “new food” products are proteins, which have so far usually been plant-based. However, processing of these protein powders poses a challenge: In order to ensure optimum product quality, the proteins must be fully unlocked, starches must be degraded to the required degree, and agglomerates and foam must be avoided during production. All of this is achieved when processing protein powders in the vacuum expansion process.
By Dr.-Ing. Hans-Joachim Jacob
What the alternative proteins used in the new food segment have in common is that they are difficult to process, and they also have very different characteristics: Wheat protein for example is extremely cohesive, while soy protein is extremely adhesive. If protein powders of seeds, grains, nuts and pulses are mixed into water, they are prone to clogging, agglutinating and foaming. The proteins are shear-sensitive on the one hand, but at the same time, they require high shearing while being dispersed into the liquid. Therefore, shearing under controlled conditions is required, in a very short period of time.
To achieve optimum product quality, what is crucial is that agglomerates that are contained in powders are instantly broken up fully when mixed into the liquid, and the formation of new agglomerates is prevented from the outset. Otherwise, these agglomerates must be broken down subsequently through long stirring and time-consuming redispersion – with negative consequences for the product quality: Dispersing the agglomerates damages the quaternary and tertiary structure of the already hydrated protein and impairs the viscosity and texture in an uncontrolled way.
Equally, with regard to the starch contained in the powder, the prevention of agglomerates is also very important. The degradation of starch usually occurs through enzymes, occasionally also through acids. If powder particles are already separated before the infeed of liquid, and highly dispersed during powder induction, the enzymatic degradation of the starch is supported and thus accelerated.
With the vacuum expansion method of the mixing and dispersion technology specialist ystral, the air contained in the powder is expanded by a multiple, which significantly enlarges the distance between the particles. The primary protein particles are separated before they enter the liquid, they are completely wetted on first contact with the liquid, they are dispersed in situ under vacuum, and are subsequently hydrated without agglomerates under pressure.
The whole process takes 2 to 3 hundredths of a second, with minimal heat input. The powder is immediately completely disintegrated. No agglomerates are formed. The texture is not damaged or destroyed. The process time compared to conventional technologies is significantly reduced here.
Through this intensive dispersion, significantly less enzymes are needed for the degradation of starch compared to conventional procedures. The air, which was previously contained in the powder, is separated from the significantly heavier dispersion through the centrifugal effect of the fast-running rotor and coalesces to large air bubbles, which can easily escape in the process vessel. Foam, which is usually generated through protein processing, is almost completely prevented this way.
The machine and system design from ystral can be precisely tailored to the requirements of the respective powder type. While for the processing of oatmeal for example – same as for soy and rice – dispersing in the vacuum expansion process with an inline operated powder wetting and dispersing machine Ystral Conti-TDS is sufficient, other powders containing protein (such as coconut or some pea flour) require additional dispersing under high shearing, to fully break down the product. In these cases, in addition to the Conti-TDS, Ystral uses a Z-Inline Disperser, which redisperses the protein powder, while the entire powder is inducted at the same time via the Conti-TDS. The Z-Inline Disperser can be operated here either in parallel in a separate circuit, or in series with the Conti-TDS.
In addition, allergenic and non-allergenic powders can for example be absorbed completely separately and processed in separate liquid circuits. A Conti-TDS can also be easily integrated into existing process systems and be piped with several process vessels or storage tanks. The disperser can either be operated inline or in the circuit on large process vessels, or generate a highly concentrated premix in a small batch, which is subsequently diluted in the main process vessels.
The mechanical processing technology has a tremendous influence on the taste, consistency, mouthfeel, and lastly also the visual impression of food – this also and particularly applies to the “new food” segment. To further improve acceptance of “new food” products on the market, it is important that they do not exhibit any deficits compared to traditional products with regard to these factors. These demands are met by technologies from ystral and the dispersing of protein powders in the vacuum expansion process.
