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Dried Samples (dried + sample)
Selected AbstractsThe essential oil of Pectis elongata Kunth occurring in north BrazilFLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2005Milton Helio L. da Silva Abstract The oils of Pectis elongata were hydrodistilled and analysed by GC and GC,MS. The major constituents identified in the oils of fresh and dried samples of a specimen collected in Pará state, Brazil, were perilla aldehyde (51.7% and 64.6%) and limonene (43.7% and 33.7%), respectively. The main compound found in the oil of a dried sample of another specimen collected in Amapá state, Brazil, was perilla aldehyde (81.9%), followed by its oxidation derivatives, perilla alcohol (5.6%) and perilla acid (4.0%). The higher percentage of perilla aldehyde in the dried samples is due to the loss of limonene during the drying stage. Probably, the plant oxidation process is initiated in the 1-methyl group of limonene, converting it to perilla alcohol and thence to the other derivatives. Copyright © 2005 John Wiley & Sons, Ltd. [source] Moisture sorption isotherm and xerophilic moulds associated with dried cocoyam chips in storage in NigeriaINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2008J. Obeta Ugwuanyi Summary Extended storage of cocoyams (Colocasia antiquorum and Colocasia esculenta) is achieved in parts of Nigeria by processing them into smoked and dried chips. In this study, cocoyam chips were collected from parts of Nigeria at the end of drying, at various periods of storage and from markets, and analysed for moisture content, moisture sorption characteristics and xerophilic moulds. Moisture content of chips ranged from 7.07 ± 1.1% for freshly dried samples to 16 ± 2.2% for samples stored up to 8 months. Six mould species from four groups of the genus Aspergillus (including five xerophiles) identified as Aspergillus fumigatus, Eurotium repens, Eurotium amstelodami, Eurotium chevalieri and Aspergillus flavus and Aspergillus niger and Mucor sp. were isolated. The variety of moulds increased with storage and moisture content of samples. Moisture sorption in dried chips showed type II sigmoidal behaviour. Wood smoke significantly protected chips from mould colonization, but in cooperation with reduced water activity. Simple and inexpensive storage of freshly dried samples in airtight bags led to prolonged storage of up to 14 months without deterioration. [source] EFFECTS of PULSED ELECTRIC FIELD ON QUALITY FACTORS and MASS TRANSFER DURING OSMOTIC DEHYDRATION of APPLESJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2003KEHINDE A. TAIWO ABSTRACT High intensity electric field pulses using varying field strengths (0.5, 1.0 and 2.0 kV/cm corresponding to 12, 48 and 192 J/kg, per pulse, respectively, with a pulse duration of 400,s) and pulse numbers (2 to 50) were applied to apple slices as a pretreatment to study their influence on mass transfer during osmotic dehydration (OD). Cell membrane permeabilzation increased with increasing field strength and higher pulse number. Higher water loss and solids gain were obtained at 1.0 kV/cm. Pretreated apples turned brown but sample brightness improved with OD time but L values decreased with increasing pulse number. Maximum deformative force and amount of strain experienced by dried samples were influenced by both the field strength and OD time. Vitamin C content of dried samples reduced at higher field strengths and longer immersion times. [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] A Novel Method for Air Drying Aloe Leaf Slices by Covering with Filter Papers as a Shrink-Proof LayerJOURNAL OF FOOD SCIENCE, Issue 9 2009S.A. Kim ABSTRACT:, To prevent the shrinkage of aloe vera slices during air drying, a method utilizing a shrink-proof layer was developed. The sample was configured of whole leaf aloe slices, where 1 side or both sides were covered with filter papers as shrink-proof layers. After air drying by varying the air temperature and the slice thickness, the drying characteristics, as well as several quality factors of the dried aloe vera leaf slices, were analyzed. In the simulation of the drying curves, the modified Page model showed the best fitness, representing a diffusion-controlled drying mechanism. Nonetheless, there was a trace of a constant-rate drying period in the samples dried by the method. Shrinkage was greatly reduced, and the rehydration ratios increased by approximately 50%. Scanning electron microscopic analysis revealed that the surface structure of original fibrous form was well sustained. FT-IR characteristics showed that the dried samples could sustain aloe polysaccharide acetylation. Furthermore, the functional properties of the dried slices including water holding capacity, swelling, and fat absorption capability were improved, and polysaccharide retention levels increased by 20% to 30%. Therefore, we concluded that application of shrink-proof layers on aloe slices provides a novel way to overcome the shrinkage problems commonly found in air drying, thereby improving their functional properties with less cost. Practical Application: This research article demonstrates a novel air drying method using shrink-proof layers to prevent the shrinkage of aloe slices. We analyzed extensively the characteristics of shrinkage mechanism and physical properties of aloe flesh gels in this drying system. We concluded that this method can be a beneficial means to retain the functional properties of dried aloe, and a potential alternative to freeze drying, which is still costly. [source] Anwendungen der Magnetresonanz zur Untersuchung von Wasser-, Temperatur- und Porenverteilung bei lebensmittelverfahrenstechnischen ProzessenCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 4 2004M. Regier Dr.-Ing. Abstract Es werden verschiedene Methoden der kernmagnetischen Resonanz (NMR) und ihrer Anwendung zur Bestimmung von Wasser-, Temperaturverteilungen und Selbstdiffusionskoeffizienten im Verlauf von Prozessen im Bereich der Lebensmittelverfahrenstechnik vorgestellt. Ausgehend von den physikalischen Grundlagen der Magnetresonanz werden verschiedene Anwendungen gezeigt, die das Potenzial besitzen, zum tieferen Verständnis der verfahrenstechnischen Prozesse beizutragen: Beispielhaft wird die Bestimmung von Wasserverteilungen bei der Rehydratation von getrockneten Proben, die Ermittlung von Temperaturverteilungen bei der Mikrowellenerwärmung und von beobachtungszeitabhängigen Selbstdiffusionskoeffizienten bei der Mikrowellen-Vakuumtrocknung gezeigt. Letztere können dazu genutzt werden, um weitere Aussagen über die innere Gewebestruktur wie Tortuosität und Porenradien zu erlangen. Applications of Magnetic Resonance for Investigating Water-, Temperature- and Poredistributions in Food Process Engineering Various methods of nuclear magnetic resonance (NMR) and their application for determinig water- and temperature distributions as well as self diffusion coefficients during food processing operations are presented. Starting from the physical basics of the magnetic resonance, various NMR applications are shown, which may contribute to a more comprehensive understanding of the food processes: Presented examples are the determination of water distributions during the rehydration of dried samples, of temperature distributions during a microwave heating process and of self diffusion coefficients during microwave vacuum drying. These observation time dependent self diffusion coefficients may be used to receive further information about the internal tissue structure, like tortuosity and pore radii. [source] | ||||||||||