Effect Of Drying Techniques Research Articles

Effect of Drying Technique on the Volatile Content of Ecuadorian Bulk and Fine-Flavor Cocoa.

Cocoa (Theobroma cacao L.) is one of the most widely consumed edible seeds in the world affected by on-farm processing. This study investigated the effect of different drying techniques, namely oven drying (OD), sun drying (SD), and a modification of sun drying using black plastic sheeting (SBPD), on the volatile profile of fine-flavor and bulk cocoa varieties analyzed by HS-SPME-GC-MS. A total of sixty-four volatile compounds were identified in fresh and dried cocoa. As expected, the volatile profile was clearly modified after the drying step, showing strong differences among cocoa varieties, this factor and its interaction with the drying technique having greater influence according to the ANOVA simultaneous component analysis. A principal component analysis revealed a close relationship between the volatile content of bulk cocoa samples dried by the OD and SD techniques, whereas slight volatile modifications were perceived among fine-flavor samples dried using the three different techniques under study. Overall, the results provide the basis for the potential application of the simplest inexpensive SBPD technique in order to accelerate the drying process of sun drying and produce cocoa with similar (fine-flavor cocoa) or improved (bulk cocoa) aromatic quality to that formed using the traditional SD or the small-scale OD.

Effects of different drying techniques on the quality and bioactive compounds of plant-based products: a critical review on current trends

Drying is one of the foremost and important steps during the processing of agricultural crops, medicinal plants and herbs to preserve their properties. The present review provides a detailed overview regarding the effect of drying techniques on the physio-chemical properties (microstructure, color, aroma composition) and bioactive compounds (phenolic compounds, carotenoids, essential oils, etc.) of plant materials. Factors affecting different drying processes and their optimization strategies have also been discussed. Furthermore, current trends in the development of drying techniques for plant materials in terms of the retention of their bioactive compounds are critically analyzed. Based on the published research articles, oven drying, and microwave drying are the preferable techniques for most plant parts; while for drying the plant extract, freeze/spray drying methods have gained higher interest. Finally, recommendations are made considering the better use of drying techniques for both plant materials and retention of their bioactive compounds.

Effect of drying technique on the morphological and textural characteristics of mesoporous silica synthesized in the microreactor

The mesoporous silica with high monodisperse inter-particle voids was obtained through different drying methods (oven, freeze, and spray) of wet-gel silica. And the wet-gel silica was prepared in the microreactor system through the precipitation of TEOS. The effects of different drying techniques on the textural properties and morphology of mesoporous silica synthesized in the microreactor were studied. The textural properties of silica were evaluated using nitrogen adsorption/desorption experiments. The morphology of the silica was described using transmission electron microscopy and field-emission scanning electron microscope. It was found that the oven drying (OD) silica exhibited the most uniform pore structures and compact structures. The freeze drying silica maintained the original network of wet-cake silica after drying. Due to the rapid and uniform heating of silica in the spray drying (SD) process, the silica obtained had the more porous structure than that of OD technique. Additionally, the surface tension of solution in the SD process affected the structures of final products. And the ethanol resulted in the more porous structures of silica than that of water.

Effect of drying techniques on extraction of Astragalus pieces

AbstractTo investigate the effect of different drying techniques on the quality of Chinese herb medicine (CHM), drying experiments of Astragalus pieces after rehydration were carried out, and four different kinds of drying techniques viz microwave drying, freeze‐drying, vacuum drying and hot‐air drying, were examined in this paper. The microstructure of dried samples was characterized by means of scanning electron microscope (SEM), and the molecular weight distribution of Astragalus pieces extract was characterized by means of ultrafiltration. Results show that dehydrated rate by microwave drying is five times faster than those by others three drying techniques. The effective component content in the extract of sample dried by microwave drying, with the molecular weight of less than 4000 Da, is higher than those by other three drying techniques. Observations of the SEM images show that the microstructure of sample dried by microwave drying is much similar to that of raw Astragalus pieces, indicating that microwave technique helps keep the penetrability of inner transmission tissues and thin‐wall cell tissues, and benefits to the extraction of effective components of Astragalus pieces. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.

The Effect of Drying Technique on Tablets Formed from Extrusion-spheronization Granules

The impact of granule drying technique (oven and freeze) on tablet strength and dissolution characteristics was investigated for a range of propyl gallate (PG)/microcrystalline cellulose (MCC)/water granules generated via extrusion-spheronization. The tablet compaction data indicated that the granule yield point (GYP) was significantly lower for the freeze-dried granular material. As a consequence, for tablets compacted to the same final applied stress, the tablet surface was visibly smoother than that of the oven-dried counterparts. Granules with a lower GYP produced tablets of increased strength. Dissolution profiles were similar for both the oven- and freeze-dried samples with the exception of one formulation, where the freeze-dried material displayed a maximum dissolution rate nearly two-fold that of the oven-dried analogue. The degree of tablet break-up during dissolution dominated the mass transfer of PG.