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Dried Product (dried + product)
Selected AbstractsDRYING OF CHILI PEPPER (CAPSCIUM FRUTSCENS)JOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2010T.Y. TUNDE-AKINTUNDE ABSTRACT Drying is one of the common methods of food preservation and is carried out on untreated/unblanched and treated/blanched chili pepper using sun, solar and hot-air drying. The drying curves generated from the three methods showed that drying of treated/blanched pepper was faster than that of untreated/unblanched pepper. The drying rate period observed for all the methods and samples was the falling rate drying regime. This suggests that the blanching pretreatment assisted water loss and thus decreased the resistance to water loss at the surface of the product. The drying time of the dried pepper varied from 27 h for hot-air drying to 144.5 h for sun drying respectively. The values of moisture diffusivity coefficient ranged from 2.163 × 10,9 m2/s for hot-air drying to 1.125 × 10,9 m2/s for sun drying. PRACTICAL APPLICATIONS A common method of preserving pepper, a vegetable with versatile use, is drying and this is done by sun, solar and oven-drying methods. Climatic variations of sun and solar drying make it unsuitable for large-scale production. Hot-air drying is thus considered as an alternative drying method because it decreases drying time and improves the hygienic quality of the dried product. Pretreating pepper by blanching increases its rate of drying. The effect of each drying method on the drying rate, equilibrium moisture content and moisture diffusivity coefficient were used to compare the drying methods. Hot-air drying had the lowest drying time whereas pretreated samples also dried faster. The effective moisture diffusivity of oven dried samples as well as pretreated samples were highest. This indicates that oven drying reduces drying time and can be used to dry pepper samples for large-scale production. [source] EFFECT OF PRETREATMENT ON DRYING TIME AND QUALITY OF CHILLI PEPPERJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2010T.Y. TUNDE-AKINTUNDE ABSTRACT A study was carried out on the effect of various pretreatments and drying methods on drying time and quality of chilli pepper. Chilli peppers were pretreated with different blanching types and concentrations of osmotic sugar solutions (60 and 70°Brix), and were dried afterward. Results indicated that the pretreated peppers dried faster than the untreated ones. The peppers soaked in osmotic solution of 70°Brix had the lowest drying time, which decreased by a variation of 33.3,41.7%, compared with the dried untreated peppers that had the highest drying time. Solar-dried peppers had higher nutritional content than peppers dried from the other methods, while the oven-dried pepper samples had the lowest vitamin A and vitamin C contents. PRACTICAL APPLICATIONS Drying gives dried samples lower nutritional quality than fresh samples because of physiological changes that takes place. Pretreatments of pepper by steam and by water blanching are common methods, but osmotic dehydration also has a significant effect on the quality of dried foods. The effect of the pretreatments and drying methods on the drying rate and nutritional quality of dried pepper were investigated. Osmotically dehydrated samples had the lowest drying time, while pretreated samples dried faster than untreated samples generally. The nutritional quality of the dried samples, however, varied with the different pretreatment methods. This indicates that pretreatment enhances drying rate and also affects the quality of the final dried product. Dried pepper can thus be pretreated with blanching or dipping in osmotic solutions for products of higher nutritional quality. This will give dried pepper that will meet the nutritional requirement of the consumers better than untreated dried pepper. [source] EFFECT OF OSMOTIC TREATMENT WITH CONCENTRATED SUGAR AND SALT SOLUTIONS ON KINETICS AND COLOR IN VACUUM CONTACT DRYINGJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2007S.M.A. RAHMAN ABSTRACT An experimental study of osmotic dehydration (OD) of selected heat-sensitive products was carried out in a laboratory-scale vacuum contact dryer. Cubes of potato and apple were examined as model heat-sensitive objects. Experiments were conducted at different conduction heat input levels with wall temperatures in the range 35,45C under vacuum and also in pure vacuum without any external heat input. Detailed investigations were carried out of OD on drying performance, product temperature and color of the dried product. PRACTICAL APPLICATIONS Osmotic treatment of potato and apple samples using concentrated sugar solution shows better osmotic dehydration as well as drying rate in a vacuum contact drying system. This information may help to select the osmotic agent in any industrial application for faster drying rate in vacuum contact drying specially for food products. Moreover this work shows the analysis to find out the starting point of precipitation of osmotic agent inside the products in terms of drying time, temperature and moisture content. This information will be helpful for critical analysis in osmotic dehydration technique which in turns may help for optimum design. [source] Freeze-drying using vacuum-induced surface freezingJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2002Martin Kramer Abstract A method of freezing during freeze-drying, which avoids undercooling of a solution and allows growth of large, dendritic ice crystals, was investigated. Aqueous solutions of mannitol, sucrose, or glycine were placed under a chamber vacuum of approximately 1 mbar at a shelf temperature of,+,10°C. Under these conditions, the solutions exhibit surface freezing to form an ice layer of approximately 1,3 mm thickness. On releasing the vacuum and lowering the shelf temperature to below the freezing point of the ice in the solution, crystal growth occurs to yield large, chimney-like ice crystals. The duration of primary drying of a frozen cake,as measured by using inverse comparative pressure measurement,was up to 20% shorter than when using a "moderate" freezing procedure (2 K shelf temperature per min). With mannitol, however, the residual moisture content of the final dried product was higher than with moderate freezing, and with sucrose and glycine there was no difference. These findings are related to the structures of the dried cakes formed during freezing, as examined by light microscopy and wide-angle X-ray diffraction. The introduction of an annealing step (4 h at a shelf temperature slightly above the onset melting point of the ice in the frozen cake) combined with the vacuum-induced surface freezing procedure maintains the rapid primary drying and produces a low residual moisture (0.2%) for the freeze-dried mannitol solution. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:433,443, 2002 [source] Synthesis and Characterization of Highly Dispersed Antimony-Doped Stannic Hydroxide Nanoparticles: Effects of the Azeotropic Solvents to Remove Water on the Properties and Microstructures of the NanoparticlesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2007Fen Yang Highly dispersed antimony (Sb)-doped stannic hydroxide nanoparticles have been successfully prepared using the solution chemistry method. The properties and microstructures of the nanoparticles are investigated in detail by means of infrared, transmission electron microscope, X-ray diffractometer, and Brunauer-Emmett-Teller nitrogen surface area measurements. The results indicate that the properties and microstructures of the nanoparticles strongly depend on the azeotropic solvents used to remove water at the drying stage. Various azeotropic solvents are screened to investigate their effects on the size and dispersivity of dried Sb-doped stannic hydroxide. Three empirical rules are drawn for selecting an effective azeotropic solvent: (1) the solvent molecule should contain at least one atom such as oxygen as the hydrogen (H)-bond acceptor to form H bonds with the surface ,OH (acting as an H-bond donor) of polymer particle; (2) the H-bond acceptor should locate in the middle of the alkane chain rather than on the terminal so that the alkane chain can stretch out and cover more surface area, improving the dispersivity of the dried product; and (3) the solvent should have a higher boiling point (,140°C) to reduce the time of azeotropic distillation for removing water and maintain a lower residual amount of azeotropic agent. Based on the empirical rules, it is discovered that iso-amyl acetate is the most effective azeotropic solvent. [source] | ||||||||||