Abstract:
The modification of the pH, crude protein and free aminoacid values
in some vegetable species (potato, cabbage, carrot, onion, garlic, peas and
beans) during culinary processing was the purpose of this work. The
vegetable products have been subjected to wetting, boiling, frying and
pickling, determining the values of pH, crude protein and free aminoacids
before and after processing. It also has analysed the water in which the
legumes were introduced and maintained, for a period of time (before
thermic processing), as well as the water where all studied vegetable
products have been boiled. The thermic processsing, depending on its type
(boiling or frying) and on analysed vegetable products, has determined
modifications of the pH and of the crude protein values, in the sense of
increasing of the first one and reducing of the second one. Thus, comparing
to raw potatoes, the pH of boiled potatoes has registered increased values,
ranged between 3,35% (in boiled tubers) and 5,52% (in fried tubers). At
onion samples, the initial pH, determined to raw samples, increased with
3,6% in boiled samples, with 5% in onion boiled water and with 5,65% in
fried onion. The evaluation of pH in carrot, cabbage and garlic, has also
shown increases of its values in thermic processed samples, less at carot
(3,44%) and garlic (4,53%) and more at cabbage (8,08%). The conservation
of cabbage through pickling process has led to a pH decrease of some 8%.
The content in crude protein of the analysed legumes reduced during the
thermic processing. Thus, comparing to raw samples, at boiled peas and
beans the crude protein reduced with 2,6% and 3,64%, and at boiled carrots
and onion with 11,4% and 8,55%. The simple contact with water (immersion)
or boiling of peas, beans, carrot and onion has led to a transmembrane efflux
of aminoacids within the mass of liquid, whose values has depended both on
the length of contact and on the legume species.
