In the past months we have evaluated about 50 different fibres from over 10 different suppliers, some even with the same specifications. We see however that every manufacturer (or processor) is having a different effect if you evaluate water absorption and oil absorption. What we have done is the following experiment:
- We take 20 gram of the fibre and add 400 gram of tap water (about 15-20°C) and let it rest/ absorb for 1 hour.
- We sieve the solution and measure how much is lost.
- To the residue we add 100 gram of oil and we wait again for 1 hour.
- We sieve the solution and let is rest for about 14 hours to see if any differences occur.
- This experiment we also executed with 20 gram of the fibre and added the oil first.
We were able to determine for most fibres how they perform and if they are more lipophilic (fat loving) or hydrophilic (water loving). The fibres that completely dissolved in water we have put to another test: how much water is required for 20 grams of fibre to lose its solid shape.
Then it is good to understand what you want to achieve:
- Is it a claim such as source of fibre (3 g/ 100 g finished product) or rich in fibre (6 g/ 100 g)
- Are you aiming at a certain nutritional or metabolism result
- Are you considering to go cleaner label and with that exchanges certain hydrocolloids, humectants, sugar or fat replacers?
- Do you require volume effects?
In the right mix you can create potentially products which even contain 15-20 g fibre per 100 gr of finished product, but this requires well thought selection of different soluble and insoluble fibres and within them various sources and fibre lengths. Longer fibre lengths have the tendency to bind already a lot initially, but due to the length of the fibre they tend to continue absorb water for quite some time. This could result in products that might seem OK the first day or so, but deterioration in the form of drying out, hardening and sometime even crumbling or falling apart appear to happen quite quickly. Encapsulated forms of fibres are another method to enrich: think of certain seeds, nuts and dried fruits. These products often consist of fats, carbs to balance taste and texture in them and provide some valuable notes in your product.
If you are aiming for using different fibre sources it is good to recognise that some vary in taste as well: some are ‘refined’ in such a way that they appear to be neutral, where others have significant amounts of minerals or residual carbs in them. For example certain oat fibres could block certain flavours, where a sugarcane fibre enhances sweetness making that a virtually same product appears to be completely different…. A good way to innovate as well!