Conclusion
Thermal processing for food preservation results in an undesired
high level of softening of carrots, mainly due to b-eliminative
depolymerization of pectin which results in decreased cell adhesion.
In context of texture improvement of thermally processed
carrots, next to the established strategy of an LTB or HP pretreatment
followed by a Ca2+ soak, a second strategy proved to be useful:
treatment at low pH. By respectively lowering the DM of the
carrot pectin or lowering the pH of the carrot tissue, the susceptibility
to b-elimination was reduced. The composition of the pH
lowering solution appeared important: cations and Ca2+ chelators
have to be avoided. Ferulic acid showed to be an effective pH lowering
component. By combining a HP pretreatment with a soak in
ferulic acid and Ca2+ thermally processed carrots could retain more
than 50% of the hardness of unprocessed carrots, due to the accumulative
effect of the different modifications. Seen increasing consumer
demand for high-quality, natural foods, ferulic acid would
be a good acidifying component as it is naturally present in fruits
and vegetables and is already used as a functional food ingredient.
However, one has to remind that, although it is a very important
quality characteristic, texture is not the only quality parameter of
concern. Therefore, the influence of the different plant modifications
on other quality parameters, for example taste of carrots,
has to be evaluated to see whether the final product meets consumer
demands.