The new drying technology of sea cucumber

In this work, we studied the drying characteristics and the quality of sea cucumbers (Stichopus japonicus) that underwent preliminary processing using microwaves during freeze drying. The qualitative parameters of the samples (FD) are compared. The results of shortening the drying period using microwave pre-treatment during drying are analyzed. Experimental data were also obtained and the rehydration process and the chemical composition (protein, carbohydrates) of the dried sample were compared.

Rehydration Process in Rustyback Fern (Aspleniumceterach L.): Profiling of Volatile Organic Compounds

When exposed to stressful conditions, plants produce numerous volatile organic compounds (VOCs) that have different biological and environmental functions. VOCs emitted during the rehydration process by the fronds of desiccation tolerant fern Aspleniumceterach L. were investigated. Headspace GC–MS analysis revealed that the volatiles profile of rustyback fern is mainly composed of fatty acid derivatives: isomeric heptadienals (over 25%) and decadienals (over 20%), other linear aldehydes, alcohols, and related compounds. Aerial parts of the rustyback fern do not contain monoterpene-type, sesquiterpene-type, and diterpene-type hydrocarbons or corresponding terpenoids. Online detection of VOCs using proton-transfer reaction mass spectrometry (PTR–MS) showed a significant increase in emission intensity of dominant volatiles during the first hours of the rehydration process. Twelve hours after re-watering, emission of detected volatiles had returned to the basal levels that corresponded to hydrated plants. During the early phase of rehydration malondialdehyde (MDA) content in fronds, as an indicator of membrane damage, decreased rapidly which implies that lipoxygenase activity is not stimulated during the recovery process of rustyback fern.

Memory Effect on a LDH/zeolite A Composite: An XRD In Situ Study

In this memory effect study, hydrotalcite-type compounds in the lamellar double hydroxide-like (LDH)/zeolite A composite material were analyzed using X-Ray Diffration XRD) in situ experiments. Three samples were analyzed: Al,Mg-LDH, Al,Mg-LDH/ZA composite, and a physical mixture (50/50 wt%) of zeolite A and Al,Mg-LDH. The Al,Mg-LDH sample was treated at 500 °C in an O2 atmosphere and subsequently rehydrated. The Al,Mg-LDH/ZA composites had three treatments: one was performed at 300 °C in a He atmosphere, and two treatments were performed with an O2 atmosphere at 300 and 500 °C. In the physical mixture, two treatments were carried out under O2 flow at 500 °C and under He flow at 300 °C. Both went through the rehydration process. All samples were also analyzed by energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The results show that the LDH phase in the Al,Mg-LDH/ZA compounds has memory effects, and thus, the compound can be calcined and rehydrated. For the LDH in the composite, the best heat treatment system is a temperature of 300 °C in an inert atmosphere.

Using endogenous pigments to recolour roasted green tea

Roasted green tea exhibits undesirable dark green that can seriously affect sensory quality, market price, and consumer acceptance. The aim of this work was to propose a method of improving the appearance of the roasted green tea. In this study, rehydration with freeze-drying (RFD) was used to recolour the tea leaves by redistributing the endogenous pigments. The results indicated that the colour of the roasted green tea changed from dark green to bright green after the RFD treatment, the values of L* and b* were significantly increased (P<0.05), and the value of a* was significantly decreased (P<0.05). In addition, the RFD treatment making the yellow–green pigments transfer onto the surface of the tea leaves also induced a change in pigment contents, including chlorophylls, carotenoids, and flavonoid glycosides. The well-defined optimum parameters for the rehydration process were moisture content of tea leaves at 35 per cent, water temperature 25 °C, and a standing time of 1.5 h.

Retrogression of Orthopyroxene-bearing Gneiss of Iboropa Akoko, Southwestern Nigeria

In this article, we report the mineral chemistry and petrographic features of charnockitic exposure of Iboropa within Precambrian Basement Complex of Nigeria. The mineral assemblages are pyroxene, plagioclase, biotite, hornblende, alkali feldspars, microperthite, quartz and ilmenite, with apatite occurring as accessory mineral. Apatite occurs in abundance as euhedral crystals. Orthopyroxene observed is strongly pleochroic and has numerous microfractures, and it is hypersthene (En45Fs54Wo1) with low TiO2 and MnO, having extremely low percentage of CaO. Hypersthene is mantled by a complex corona of amphibole, and the amphibole is hornblende with a chemical formula: (K,Na)(Ca,Fe)2 (Fe,Mg,Al,Ti)5(Al,Si)8O22(OH)2. Plagioclase occurs as inclusions in both pyroxene and biotite. Biotite has high concentration of TiO2 and extremely low CaO. The opaque mineral observed is ilmenite and it is concentrated around hypersthene and amphibole. Rare earth element (REE) displays negative Eu anomaly with enrichment of light REE over heavy REE. Amphiboles surrounding orthopyroxene are evidences of retrograde reactions and are formed at the expense of orthopyroxene reacting with plagioclase and quartz in the presence of fluid. The relationship between the mineral assemblages suggests the retrogression of the gneiss that might be as a result of rehydration process, and it is a transition from granulite facies to amphibolite facies during a retrogressive form of metamorphism.

Modelling of Rehydration Kinetics of Desert Truffles (Terfezia spp.) Dried by Microwave Oven

It is very important to develop a new way of treatment for foodstuffs to provide consumers more chances to choose their foods. In the present study, we aimed to investigate the effect of microwave drying conditions on the rehydration process of Algerian truffles. Previously dried truffles, at different microwave power output (350, 500 and 650 Watt) and weights (100 and 150 g) have been utilized to analyses and to model the rehydration kinetics. Among the six used empirical models, Weibull model has been the most fitted model to all the treated samples. Microwave power output and sample weight were found to have an effect on truffles during drying, and consequently on their rehydration capacity. The high samples amount has decreased the effects of microwave drying by decreasing the density of treatment, also, the high-power output has probably reduced the time of evaporation, and thus more preservation to the dried truffles. These results can be taken into consideration for more industrial applications of microwave drying and subsequent rehydration of truffles.

Mineralogical Analysis of Portland Cement Pastes Rehydrated

Hydrated products, such as (hydrated) cement pastes, decomposition through physical-chemical alterations when submitted to high temperatures. One of the main factors that lead to microstructural changes during calcination up to 800ºC, is the dehydration phases of hydrated Portland cement. The present study sought to characterize crystalline phases occurring before and after calcination to the produced pastes using X-ray diffraction (XRD) analysis. Cement pastes were produced using Portland cement CP V-ARI RS, similar to type II (ASTM C150-07), with water/cement ratio 0.5. After a 28-day curing period, the pastes were calcinated at 800°C for 60 minutes with a 10°C/min heating rate. Afterwards, the newly produced hydraulic binder was cooled abruptly and reactivated through a rehydration process, and underwent analyses on the 7 and 28 day. During this study it was observed that the originally hydrated products can be rehydrated.

Studying the application of dielectric pretreatment before drying

In this paper, we studied the characteristics of drying red beets that were pretreated using microwaves before convective drying. The results of shortening the drying period using microwave pre-treatment during drying are analyzed. Experimental data were also obtained and the rehydration process of the dried sample was compared.