Encapsulation is key to working out vitamin solubility issues

The enrichment of vitamins into functional food products can be challenging for many reasons, not least of all because of issues of solubility with many vitamins. Speaking with NutraIngredients Ram Chaudhari, PhD, chief scientific officer for Fortitech explained that finding the right form of a vitamin to match the food matrix it will be added to is a vital part to solving the problem.

One of the main challenges for manufacturers comes with the incorporation of fat soluble vitamins – namely vitamins A,D, E,K, and beta-carotene – into food and beverage formulations. Chaudhari said that this can pose several technical challenges to formulators and manufacturers, but noted that solutions do exist and in many cases have been in use for a number of years.

Fat vs Water soluble​

One of the main challenges in addressing solubility issues, he explained, is choosing the right form of a vitamin initially.

“Choosing the right form of vitamin, so that they are soluble in the aqueous or semi-aqueous phase, is very important. Depending on the finished product form, then there are different choices of vitamin forms that may work in different situations,”​ said Chaudhari.

“With fat soluble vitamins you have to be very careful when formulating,”​ he warned. “But for water soluble vitamins there is no issue, because they are able to disperse in solutions very easily.”​

Chaudhari said even in foods that high very high levels of fat content, “there will always be some form of aqueous phase, so a water soluble vitamin provide less of a problem.” ​

However, he explained that fat soluble vitamins can be “very tricky”​ to work with, and as such require additional formulation measures, such as encapsulations and the use of hydrocolloid stabilisers and emulsifiers can help to keep a uniform distribution.

“You have to apply micro-encapsulations or use additional ingredients that will hold these vitamins in a uniform fashion to make the mixture acceptable to the consumer,”​ he said, adding that fat soluble vitamins are almost always microencapsulated in order to assist in their formulatiuon in water based products.

“You have to use the right form of the vitamins, and the right encapsulation methods to help the particles disperse in the correct way,”​ explained Chaudhari.

Size matters​

One factor that can play an important role in solubility is size, and according to the Fortitech expert, the when it comes to size; the smaller the better.

Nano-encapsulation and use of micro and nano-emulsions has helped to solve many problems with getting ingredients into food and beverage formulations, explained Chaudhari.

He added that suspending fat soluble ingredients such as vitamins in a nano-emulsion will has great benefits because the small size of the particles means that even if they are not soluble in the matrix, they have little influence on important sensory factors such as flavour and mouth feel – and are still highly bioavailable for digestion.

“The smaller the particles, the more surface area, so from a bioavailability point of view you will have no problems,”​ he added.

Encapsulation balance​

In addition to the size of particles, getting the right type of encapsulation is absolutely vital to the success of a vitamin enrichment, said Chaudhari – who explained that it is important to get the right balance between protection in the food matrix, and break down in the gut.

On one hand, he said that the material must protect the encapsulated vitamins and stop reactions and the chemical breakdown of vitamins in the product. A lack of protection can have negative impact on bioavailability of the vitamin, because there is less of it, and can also cause the formation of off flavours and other issues in the formulation, said Chaudhari.

On the other hand, he explained that, the vitamin must be able to break down in digestive system, and should not be so well protected that it simply passes through the body.

“Finding the right encapsulation materials to strike this balance can be complicated, as every vitamin and each type of food matrix behave differently, and have different interactions to consider, meaning different solutions are required for even a slight change in matrix,” ​said Chaudhari.

If the encapsulation material is wrong, the vitamin will likely be either exposed to early and break down before it reaches the consumer, or it will pass right through them, he said:

“If you ‘bullet proof’ a vitamin, for example to make it more stable, and then of course this will minimise the interactions. So you improve this one thing, but then what good will that do, because the vitamin is bullet proof and will not be hydrolysed and utilised in the intestine.”​

He explained that the right balance would see a coating that was rapidly broken down by the enzymes in the gut, but offered strong protection from interactions in other situations – such during production and while the product may be sat on a shelf for several weeks or months.