particulars of the system determine the boundary conditions for application
of a theory and thereby the final result.
All of this might lead to the opinion that many of the problems
encountered in food science and technology are so intricate that application
of sound physical chemistry would hardly be possible and that quantitative
prediction of results would often be impossible. Nevertheless, making use of
the basic science involved can be quite fruitful, as has been shown for a wide
variety of problems. Reasons for this are
Understanding of basic principles may in itself be useful. A fortunate
characteristic of human nature is the desire to explain phenomena
observed and to create a framework that appears to fit the
observations. However, if such theorizing is not based on sound
principles it will often lead to wrong conclusions, which readily lead
to further problems when proceeding on the conceived ideas with
research or process development. Basic knowledge is a great help in
(a) identifying and explaining mechanisms involved in a process and
(b) establishing (semi-)quantitative relations.
Even semiquantitative answers, such as giving the order of magnitude,
can be very helpful. Mere qualitative reasoning can be quite
misleading. For instance, a certain reaction proceeds much faster at
a higher temperature and it is assumed that this is because the
viscosity is lower at a higher temperature. This may be true, but only
if (a) the reaction rate is diffusion controlled, and (b) the relative
increase of rate is about equal to the relative decrease in viscosity.
When the rate increases by a factor of 50 and the viscosity decreases
by a factor of 2, the assumption is clearly wrong.
Foods are intricate systems and also have to meet a great number of
widely different specifications. This means that process and product
development will always involve trial and error. However, basic
understanding and semiquantitative relations may greatly reduce
the number of trials that will lead to error.
The possibilities for establishing quantitative relations are rapidly
increasing. This is due to further development of theory and
especially to the greatly increased power of computer systems used
for mathematical modeling of various kinds. In other words, several
processes occurring in such complex systems as foods—or in model
systems that contain all the essential elements—can now be modeled
or simulated.
Altogether, in the author’s opinion, application of physical chemistry
and mesoscopic physics in the realm of food science and technology is often
needed—besides food chemistry, food process engineering, and food