The influence of blanching pretreatments on the quality of dehydrated broccoli stems/ Influencia del tipo de escaldado en la calidad de tallos de bróculi deshidratados
2000
Sanjuan, N. | Benedito, J. | Clemente, G. | Mulet, A.
Different blanching treatments were applied to sliced broccoli stems prior to dehydration in order to improve product quality. The pretreatments used were a conventional blanching in water at 100°C, and a stepwise blanching using different temperatures for the first step (50, 55, 60, 65 and 70°C). Five rehydration temperatures were used (25, 40, 55, 65 and 80 °C). Rehydration rate, chlorophyll content and texture of the rehydrated product were evaluated. Rehydration was modeled based on Fick's diffusion equation. A good agreement between the model and the experimental data was obtained when Dₑff and Wₑ values were identified for each temperature (average percent variation 99.3). Samples stepwise blanched at 60 °C showed, on average, the lowest W ₑ and Eₐ values. Stepwise blanching at 60 and 65 °C and rehydration at 25, 40 and 55 °C were the combinations that gave the firmest product. Stepwise blanching at 50 °C and rehydration between 25 and 65 °C was the combination that preserved the highest chlorophyll content. From these results, it seems difficult to obtain firm samples with high chlorophyll content without any chemical additive.
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