Firmness changes of impregnated whole peeled prickly pear
- Additional Document Info
- View All
The firmness of green prickly pear fruits (Opuntia ficus indica) impregnated with a sucrose isotonic solution (IS) was evaluated. Whole fresh-peeled prickly pears were processed under different combinations of vacuum pressure (pv), vacuum application time (tv) and relaxation time (tr). Puncture test was applied to impregnated and fresh whole prickly pears. The maximum force (Fmax), average force (Fav) and the work (Wp) required to puncture 3 cm in the fruits were measured. Second order models provided good fits to the experimental data of Fmax (R2 = 0.754), Fav (R2 = 0.788) and Wp (R2 = 0.792). Impregnation factors p v, tr, tv-tr significantly affected firmness parameters (P ¿ 0.05). Firmness parameters of fresh-peeled prickly pear were Fmax = 10.934 ± 1.571 N, Fav = 2.152 ± 0.270 N and Wp = 5.930 × 10-2 ± 0.0054 Nm. Firmness reduction of impregnated fruits was linked to the IS impregnation levels and deformation-relaxation phenomena. PRACTICAL APPLICATIONS The aim of this study was to assess the influence of impregnation conditions on firmness of whole peeled prickly pear, as excessive softening is the main factor limiting consumer acceptability. This study helps to identify the better impregnation conditions for maintaining firmness. This information could be useful for the application of vacuum impregnation in the development of fruits and vegetables products, in which the impregnating solution is used as a carrier of active agents. To date, very limited studies have been conducted in whole fruits involving only peeling and impregnation operations. © 2009, Wiley Periodicals, Inc.