Scientists from India’s Central Food Technological Research Institute in Mysore report that fortification with the prebiotic fibre does not affect the colour, pH, or the amount of solids in the beverage.
Moreover, the initial FOS content of juices made from pineapple, mango or orange were all about 3.5 grams per 100 millilitres.
“The present study clearly indicates that fruit juice beverages can successfully be fortified with FOS with shelf life of 4 months and 6 months at ambient and refrigeration temperature respectively,” wrote the researchers in the journal LWT – Food Science and Technology.
“The present study has opened up a new avenue for the preparation of a commonly available, hugely popular healthy beverage.”
The study does not prove however that a prebiotic effect is achieved by consuming the beverages. Prebiotics are currently defined as "nondigestible substances that provide a beneficial physiological effect on the host by selectively stimulating the favourable growth or activity of a limited number of indigenous bacteria".
Modern recommendations for inulin and oligofructose are between five and eight grams per day.
The Indian researchers prepared FOS by enzymatically transforming surcrose and then added this for fruit juice beverages as a partial replacement of sucrose. Shelf life experiments showed that the beverages were stable for four months without any significant loss of quality.
Sensory analysis showed no undesirable changes, particularly for colour of the product. “This indicates the stability of the fruit juice beverages fortified with FOS over storage and the beverages retained all the desirable sensorial properties, as compared to control. Results also indicated that there was no noticeable change in the colour during storage,” wrote the researchers.
“This has an important bearing on the consumer acceptance of the fortified juices, as colour is one of the primary quality characteristics, which appeals to the consumer,” they added.
The burgeoning prebiotic market has been largely created by three inulin producers, all based in Europe. Other ingredient manufacturers are increasingly looking to promote the prebiotic effect of their products as evidence suggests that prebiotics could be even more useful than the probiotic bacteria that they feed.
Prebiotic ingredients, or those that boost the growth of beneficial probiotic bacteria in the gut, are worth about €90 million in the European marketplace but are forecast to reach €179.7 million by 2010, according to Frost & Sullivan.
The big inulin producers, particularly Beneo-Orafti, have been influential in building the science behind inulin and oligofructose, backing research into potential benefits for a variety of health conditions ranging from bones to colorectal cancer, from immunity to satiety and weight management.
Source: LWT - Food Science and TechnologyPublished online ahead of print, doi: 10.1016/j.lwt.2008.11.004“Fructooligosaccharide fortification of selected fruit juice beverages: Effect on the quality”Authors: B. Renuka, S.G. Kulkarni, P. Vijayanand, S.G. Prapulla