a b s t r a c t
The application of vacuum impregnation (VI) for the production of high quality fresh like apple products
has been investigated. Preliminary tests were carried out to select the optimal VI treatment conditions
(P: 857e50 mbar; VI time: 10e1000 s). The use of isotonic sorbitol, glucose, fructose, sucrose, trehalose
and maltose solutions was then studied to keep quality and improve stability of the VI treated apples. VI
at 738 mbar for 10 s allowed the penetration of the impregnation agent (water) with minimal effects on
fruit composition and quality. VI isotonic solutions determined a limited solute increase while affected
mechanical properties positively; firmness of apples processed with sorbitol solution was higher than
that of the fresh fruit. Moreover, they contributed to preserve apples from browning. After 7 days, h
values significantly higher than the untreated samples were obtained with
trehalose > sorbitol > glucose > sucrose > maltose. Sensory analysis confirmed the positive effect of
isotonic VI solution on apples quality.
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