Frequently asked questions
What exactly are whole soya beverages, and how do they differ from traditional or regular soya beverages? What are their properties and characteristics? What is the best production process, and what are the main challenges involved? Find the answers here.
What are whole soya beverages?
- These are full-fibre beverages that utilise 100% of the soya bean, including the bean hull.
- Therefore, all dietary fibres from the bean are still present in the final beverage.
- In comparison to regular or traditional soya beverages, the fibre and protein content is thus increased.
- As the production process uses the whole bean, it generates zero okara waste.
What are their properties and characteristics?
- Whole soya beverages are noted for being healthy and nutritious, and for having a rich, creamy taste together with a smooth texture and pleasant mouthfeel.
- They have a high dietary fibre content along with retaining a high proportion of the calcium in soya beans, and about 40% of the soya bean protein.
- Usually, no added stabilizers, emulsifiers, or thickening agents are required for the end product.
- This means whole soya beverages support a clean label strategy and have shelf-life stability.
- They also have a 100% yield and generate more beverage from the same volume of beans (compared to traditional soya extraction).
How do whole bean soya beverages differ from traditional or classic soya beverages?
- The viscosity of whole bean soya beverages is usually higher than traditional soya beverages due to the higher fibre content.
- Processing this fibre well gives whole bean soya beverages their rich, creamy taste.
- Traditional extracted soya is also less nutrient-dense and fibre-rich, containing less protein and less fibre.
- Furthermore, traditional extracted soya generates waste – 1.5 to 2kg of okara waste for every kg of beans used..
- Average processing gives only 60% yield (where 1kg of beans once generated 7 litres of beverage, with whole soya 12 litres are produced from that same 1kg).
- There are many different types of traditional soya beverages fulfilling specific demands – see table below.
Type |
Description |
| High solids or rich soya beverages | Made by water extraction from whole soyabeans, using a bean-to-water ratio of 1:5 (approx. 4% protein). |
| Dairy-like soya extract | Composition is similar to that of dairy products. The bean to water ratio is approximately 1:7 (protein content 3.5%). It is slightly sweetened, and oil and salt are added to similar properties to that of dairy milk. |
| Barista soya beverages | Formulation includes specific stabilizer / emulsifier to ensure stability, good foam, pH of 7+, with low beany base, can be mildly flavoured with vanilla / milk / cream aroma. |
| Lower solids soya beverages | Sweetened and flavoured drinks (approx. 1% protein) with a bean to water ratio of 1:20. |
| Soya extract-based fruit juices or milk-like beverages | Mixtures of soya extract with fruit juice, other plant extracts or dairy milk. |
What is okara?
- Also known as soy pulp, okara is the insoluble by-product of soya beans that remain after filtering soya slurry during the production of traditional soya beverages.
- Generally white or yellowish in colour, fresh okara contains 76 to 80% moisture, and 2.6 to 4.0% protein.
- Traditionally, okara was used as livestock feed – especially for pigs and dairy cows – and as a natural fertiliser or compost.
- It has also formed part of traditional cuisines in Japan, Korea, and China.
- However, new regulations, and the fact that fresh okara is prone to putrefaction, have severely limited its commercial use..
- As such, okara is now often considered a waste product, and can be costly and time-consuming to dispose of efficiently and sustainably.
Is it possible to produce zero okara waste soya beverages?
- In a traditional commercial soya beverage line, fibrous elements (the okara) are separated and removed during an early stage, after enzyme deactivation.
- In a whole soya beverage, no fibre or other ingredients in the raw materials are removed – the focus instead is on reducing the particle size of the fibre, and carefully controlling the final texture and taste.
- Advancement in grinding and milling technology means that better particle size reduction is now possible, leading to an acceptable mouthfeel for whole soya beverages.
- Not only does whole soya production give more beverage from every bean, it produces zero okara waste, eliminating the hassle and cost of waste handling.
What is the production process for whole soya beverages?
- Grinding – Important to have proper control over grinding to achieve an appropriately small particle size to facilitate the extraction of solids and nutrients to the clarified liquid soya extract (initial grinding is done with the same grinders as traditional soya beverages)
- Heat Treatment – To deactivate the trypsin inhibitors, the liquid soya slurry is pumped into a steam injection system where it is heated to and maintained at a required temperature for deactivation (typically based on 85% deactivation, which corresponds to the maximum protein efficiency ratio).
- Fine Grinding – A smart combination of grinding, shearing, and homogenization processes allows for the incorporation of solid fractions of the soya slurry into the beverage, instead of separating them by decanter as an okara side stream. The heavy/intense treatment in this step ensures the required reduction in particle size to produce a pleasant beverage. However, flow, pressure, shearing, and other parameters need to be adjusted to achieve optimal results for whole soya bean beverages.
- Mixing/Formulation – Mixing is done to disperse the ingredients in water and ensure that they dissolve and hydrate raw materials, form stable fat droplets/emulsions, and disperse small particles.
- UHT Heat Treatment – After separation and final beverage blending, the product is heat treated in an ultra-high temperature (UHT) unit at a temperature of at least 137°C and minimum holding time of 4 seconds (both steam injection and indirect heating can be used in commercial production).
- Deaeration – This is recommended to reduce oxygen levels to ensure a good quality product, reduce fouling, and reduce foam when filling (this should take place before indirect heating; if direct heat is used, deaeration takes place after heat treatment).
- Homogenization – Downstream homogenization is by far the most common arrangement to avoid “sandiness” in the product, and for whole soya beverages, homogenization pressure is normally higher than for traditional soya beverages – 400 to 600 bars – to break down particle size further.
- Filling – After homogenization and final cooling, the product is sent to an aseptic tank for intermediate storage before it is packed.
What equipment is involved?
- A best-practice line for whole bean soya beverages will consist of: a grinder, a heat treatment unit, a fine grinding unit, a mixer, a blender, a UHT unit, aseptic storage, a CIP unit, and a filling machine.
What are the main production challenges of whole soya?
- For full-fibre soya beverage production, the particle size is the most important factor, as it affects all other quality parameters. This makes the fine grinder capability and settings crucial for success.
- Heat treatment not only deactivates trypsin inhibitors but also causes the formation of protein aggregates, which leads to an increased risk of precipitation and sedimentation. However, these particles are looser and will break easily in the homogenization stage later.
- Soya base is a naturally foamy product, so precautions need to be taken in the mixer to avoid foam. A vacuum in the mixer will do this, and will also decrease air content in the product (lower air content will also improve running times in UHT and reduce wear on the homogenizer).
- “Sandiness” in the product comes from aggregates that form during heat treatment – this means that UHT should be configured such that the product is homogenized after the main heat treatment.
- With homogenization, as you increase the pressure, you get less payoff in terms of particle reduction – finding the balance between particle breakdown efficiency and energy consumption is key (this inflexion point will vary from one formulation to another).
- Smaller particle sizes contribute greatly to a reduction of bitterness in taste perception tests, as well as to the perception of creaminess. Finding the inflexion point that matches desirable product characteristics leads to a more efficient design of the homogenization and grinding steps.
Can I convert/upgrade my existing soya line to whole bean soya?
- Yes, an existing soya beverage production line can be converted or upgraded to produce whole bean soya. This requires limited capital investment in new equipment.
- Such a line will then be capable of producing both regular soya beverages and whole soya beverages.
- The specific elements normally required to produce whole soya beverages are:
- Valve arrangement to bypass the decanter or the high-shear units, enabling the production of both whole and regular soya beverages.
- Possible review of the design of the UHT unit depending on the rheological properties of the new whole bean soya products.
- A high-shear unit.
- An additional homogenizer, placed after the two high-shear units, specially designed to enable the processing of products including fibres.
- CIP pressure line for cleaning any bypasses and high-shear units.
- Both upstream and downstream homogenizers can be upgraded with different configurations to run new products.
