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- Influence of pretreatments on quality parameters and nutritional compounds of dried galega Kale (Brassica oleracea L. var. acephala)Publication . Araújo, Ana C.; Oliveira, Sara M.; Ramos, Inês N.; Brandão, Teresa R. S.; Silva, Cristina L. M.The objective of this work was to evaluate the effect of six pretreatments on quality and nutritional contents of sliced Galega kale submitted to convective drying. Among all treatments, steam blanching was the most favourable, allowing improvements in retention of vitamin C, total antioxidant capacity and chlorophylls in comparison to the absence of pretreatment. Total phenolic losses were not reduced by steam blanching, but the retention was improved by combining this approach with a previous immersion in a metabisulphite solution. Moreover, steamblanching improved the colour parameters and appearance, providing a final dried product more similar to the fresh sample.
- Influence of air-drying temperature on the quality and bioactive characteristics of dried galega kale (Brassica Oleracea L. Var. Acephala)Publication . Oliveira, Sara M.; Ramos, Inês N.; Brandão, Teresa R. S.; Silva, Cristina L. M.Drying processes are often applied to preserve and increase the shelf life of vegetables. These products contain an extensive collection of phytochemicals known to provide health benefits. However, these compounds generally undergo significant degradation during drying because of their sensitivity to heat, light, oxygen, as well as to leaching phenomena. Thus, increased attention has been given to the concerns regarding the quality degradation of vegetables during drying. Galega kale was selected, since this leafy vegetable, often included as soups ingredient, presents high amounts of vitamins and micronutrients. The objective of this work was to evaluate the drying characteristics and the effect of drying temperature on quality characteristics of Galega kale, without any pretreatment. Drying times of 330, 162, 78 and 51 min provided minimal moisture contents, using temperatures of 35, 50, 70 and 85 ⁰C, respectively. Increasing air-drying temperatures originated significant changes in color and nutritional parameters. The L* and a* values diminished, and b* increased, originating increasing values of chroma, total colour difference and browning index, as well as decreasing values of hue angle. A pronounced effect on the retention of total phenolic compounds was observed. Regarding antioxidant capacity and vitamin C, losses of 51.7±7.5- 69.6±3.7 and 4.8±9.7-55.5±7.4% were obtained, respectively. Chlorophyll a content decreased with increasing drying temperatures, with losses between 8.9±6.7 and 35±5.6%, while degradation of chlorophyll b was negligible. In conclusion, the air-drying of Galega kale without any pretreatment resulted in considerable deterioration of its quality characteristics and nutritional value.
- Influence of air-drying temperature on the quality and bioactive characteristics of dried galega kale (Brassica Oleracea L. Var. AcephalaPublication . Oliveira, Sara M.; Ramos, Inês N.; Brandão, Teresa R. S.; Silva, Cristina L. M.
- Evaluation of drying and storage conditions on nutritional and sensory properties of dried galega kale (Brassica oleracea L. var. Acephala)Publication . Araújo, Ana C.; Oliveira, Sara M.; Ramos, Inês N.; Brandão, Teresa R. S.; Monteiro, Maria J.; Silva, Cristina L. M.This work evaluated the effect of the air-drying temperature and vacuum packaging on quality and nutritional compounds of dehydrated galega kale, previously steam blanched, during 5 months of storage. When compared with the vacuum packaged kale, the packaging without vacuum yielded improved nutritional features, in general. This approach combined with a drying temperature of 40°C resulted in retention percentages of 62, 38, 92, and 48% for vitamin C, total phenolic content, total antioxidant capacity, and chlorophylls, respectively. The acceptance of the dried product by the consumer was assessed through a focus group. The participants classified the product as a practical and convenient alternative to cook healthier dishes. The appearance of dried galega kale was described as being fragile and being with nice smell, natural colour, and flavour similar to the fresh product. In conclusion, the herein presented product was addressed as an innovation with multiple possible applications in several recipes.
- Effect of convective and freeze-drying processes on galega kale qualityPublication . Tasin, Luca; Ramos, Inês N.; Oliveira, Sara M.; Brandão, Teresa R.S.; Silva, Cristina L. M.
- Estimation of water diffusivity parameters on grape dynamic dryingPublication . Ramos, Inês N.; Miranda, João M.R.; Brandão, Teresa R.S.; Silva, Cristina L.M.A computer program was developed, aiming at estimating water diffusivity parameters in a dynamic drying process with grapes, assessing the predictability of corresponding non-isothermal drying curves. It numerically solves Fick’s second law for a sphere, by explicit finite differences, in a shrinking system, with anisotropic properties and changing boundary conditions. Experiments were performed in a pilot convective dryer, with simulated air conditions observed in a solar dryer, for modelling the process. The equivalent radius of grapes decreased 30% until the end of the process, stressing the need to include shrinkage in mass and heat transfer models. It was observed that macroscopic shrinkage reflects cellular shrinkage, if plotted versus the normalised water content. Diffusivity values ranged between 1 10 16 and 1 10 10 m2/s. The developed methodology yields very good prediction of dynamic drying curves.
- Phytochemical and physicochemical properties of dried orange peel as affected by processing conditionsPublication . Phuon, Vichearavann; Brandão, Teresa R. S.; Ramos, Inês N.; Silva, Cristina L. M.
- Phytochemical and physicochemical properties of dried orange peel as affected by processing conditionsPublication . Phuon, Vichearavann; Brandão, Teresa R. S.; Ramos, Inês N.; Silva, Cristina L. M.
- Effect of air-drying temperature on the quality and bioactive characteristics of dried galega kale (brassica oleracea l. var. acephala)Publication . Oliveira, Sara M.; Ramos, Inês N.; Brandão, Teresa R. S.; Silva, Cristina L.M.The objective of this work was to evaluate the drying characteristics and the effect of drying temperature on the quality characteristics of Galega kale without any pretreatment. Drying times of 330, 162, 78 and 51 min provided minimal moisture contents, using temperatures of 35, 50, 70 and 85C, respectively. The L* and a* values diminished and b* increased, resulting in increasing values of chroma, total color difference and browning index, as well as decreasing values of the hue angle. A pronounced effect on the retention of total phenolic compounds and vitamin C losses ranging from 4.8 ± 9.7 to 55.5 ± 7.4% were observed. Regarding antioxidant capacity, losses from 51.7 ± 7.5 to 69.6 ± 3.7% were obtained. Chlorophyll a content decreased with increasing drying temperatures, with losses between 8.9 ± 6.7 and 35 ± 5.6%, while degradation of chlorophyll b was negligible. In conclusion, the air drying of Galega kale without any pretreatment resulted in considerable deterioration of its quality characteristics and nutritional value.
- Effect of pretreatments on quality parameters and nutritional compounds of dried Galega kale (Brassica Oleracea L. Var. Acephala)Publication . Araújo, Ana C.; Oliveira, Sara M.; Ramos, Inês N.; Brandão, Teresa R. S.; Silva, Cristina L. M.