Consistency of UHT beverages enriched with insoluble fibre during storage

The investigation deals with the effect of incorporating insoluble fibre in UHT treated beverages in order to improve the nutritional profile of these product concepts. A variety of insoluble fibres are used including orange fibre, kibbled wheat fibre and oat fibre, whose particle size distribution ranges over an order of magnitude from 372 to 35 µm. The work demonstrates that the overall acceptability of UHT beverages is significantly affected by the particle size distribution and level of fibre addition varying from 0.5 to 5% w/w in formulations. The colour appearance of the UHT beverages is also influenced by the incorporation of insoluble fibre where preparations with wheat fibre appear darker than their counterparts. Results indicate a positive relationship between fibre characteristics and beverage consistency, with increasing concentration or size distribution in particles yielding higher steady-shear viscosity. Further, extended storage over 12 weeks at 22 °C exhibits increasing viscosity at a given concentration and type of fibre, whereas storage at 30 °C results in increasing flow, which is an interesting outcome for the commercialisation of the industrially based formulations.