Effects Of Hydrothermal Processes Research Articles

Hydrothermal processes and simultaneous enzymatic hydrolysis in the production of modified cassava starches with porous-surfaces

The amylolytic action of α-amylase and amyloglucosidase has been directly implemented in native cassava starches for the formation of cassava microporous granules with unsatisfactory results, however, its incidence in hydrothermally treated granules has never been evaluated. The effect of hydrothermal processes and simultaneous enzymatic hydrolysis on the physicochemical, morphological and structural properties of native cassava starch was evaluated. Native cassava starch presented a rigid, smooth surface, and was exempt from porosities, whereas hydrothermal processes altered the semicrystalline order and increasing the size and number of pores and increasing the size (4.11 ± 0.09 nm) and volume of pores (0.82 ± 0.00 cm3/g × 10−3). The hydrothermal action followed by enzymatic processes with α-amylase and amyloglucosidase, augmented the processes of internal degradation (endo-erosion) and pore widening (exo-erosion), improving the hydrophilic properties compared to the hydrothermal treatment. Likewise, the hydrothermally process followed by enzymatic hydrolysis for 24 h (HPS + EMS-24) increased the degradation of the amorphous lamellae, consistent with a significant decrease in amylose content. This same dual treatment increased the pore size at 17.68 ± 0.13 nm relative to the native counterpart; therefore, they are considered an effective method in the development of modified cassava starches with porous surfaces.

Effect of hydrothermal process on the pyrolysis of oily sludge: Characterization and analysis of pyrolysis products

In this paper, the effect of the pretreatment method combined with hydrothermal treatment and in situ mechanical compression (HT-MC) on the pyrolysis characteristics of oily sludge (OS) was investigated. The results of the thermal analysis showed that the temperature range in different pyrolysis stage intervals shifted to a lower level and the weight loss rate decreased significantly after HT-MC. Isoconversional methods were employed with an estimated apparent activation energy of 92.66 –198.21 kJ·mol−1 for the pyrolysis of OS after HT-MC. As the hydrothermal temperature increased to 240 °C, the yield of char increased from 80.44 to 86.08 wt%, and the yield of oil decreased from 16.03 to 11.23 wt%. Compared to the raw material, the gas products from the pyrolysis of OS after HT-MC had a higher H2 concentration and yield. The analysis results of GC-MC showed that, compared with the pyrolysis oil obtained by direct pyrolysis, the content of olefins in pyrolysis oil obtained in pyrolysis of OS after hydrothermal treatment increased from 0.86 % to 5.73 %. Furthermore, the relative content of alkanes in pyrolysis oil increased from 76.12 % to 87.40 % with the rise of hydrothermal temperature from 160 to 240 °C.

Study on preparation process and enhanced piezoelectric performance of pine-needle-like ZnO@PVDF composite nanofibers

The effect of hydrothermal process on the morphology and piezoelectric performance of zinc oxide/polyvinylidene fluoride (ZnO@PVDF) composite nanofibers is rarely studied. In this work, highly aligned ZnO nanorods were epitaxially grown on the electrospun PVDF nanofibers to form ZnO@PVDF composite nanofibers with a pine-needle-like bionic structure. Nanofibers before and after hydrothermal reaction were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and piezoelectric analysis. Results demonstrated that hydrothermal reaction conditions, including mass ratio of ZnCl2 to HMTA, ammonium hydroxide volume, hydrothermal reaction time and temperature should be carefully controlled and cooperated with each other to produce ZnO nanorods with ideal microstructure and piezoelectric performance. FTIR and XRD results confirmed the transformation of β phase in PVDF nanofibers from α phase in PVDF powder due to the elongation under strong electric field during electrospinning. Results of SEM and XRD certified the successful growth of ZnO nanorods with hexagonal wurtzite structure, which plays an important role in facilitating the percentage of β phase and the resulted piezoelectric capacity of ZnO@PVDF composite nanofibers. All of these characterizations suggest that the proposed pine-needle-like ZnO@PVDF composite nanofibers demonstrate promising potential in the wide application of electromechanical energy conversion.

Impact of hydrothermal processing on Job's tears grain fractions and its protein isolates: Evaluation of digestibility, functionality, and anti‐nutritional factors

The study was focused on the effect of hydrothermal processing on the protein characteristics of Job's tears grain and its corresponding milled fractions. The protein isolated from native and treated grains was studied for their functional and physicochemical properties. The protein content of native and hydrothermally treated Job's tears was 20%–20.27%, 11.85%–12.26%, and 12.95%–13.70% in bran, endosperm, and germ-rich fractions, respectively. Hydrothermal processing improved the in vitro protein digestibility of grain fractions (up to 38%) and protein isolates (40%–55%) and decreased the anti-nutritional factors. There was a significant change in the surface hydrophobicity of globulin (148.91–1,191.30), glutelin (108.54–791.47), and prolamine (823.68–2,352.00) in the grain fractions. The water absorption capacity of processed Job's tears protein isolates remained unaffected; however, the oil absorption (5.45 ± 0.02 to 7.61 ± 0.46), emulsion (16.02 ± 0.01 to 26.06 ± 0.13), and foaming capacity (14.16 ± 0.08 to 28.33 ± 0.02) improved. Job's tears protein was found to be of high quality with potential for food application as functional ingredient after hydrothermal processing. Novelty impact statement Job's tears grain is a nutritious but underutilized millet with very few reports available on the processing of the grain. The novelty of this paper lies in the hydrothermal processing, fractionation, and isolation of protein from the grain, the increase in protein digestibility of hydrothermally processed Job's tears grain fractions (bran, endosperm, and germ-rich fractions), and the decrease in the anti-nutritional factors that hampers the protein digestion. Moreover, by fractionating the grain, nutrient-dense milled fractions were obtained which can be used as a food ingredient in product development.

Effect of hydrothermal processing on ginseng extract

BackgroundPanax ginseng Meyer is cultivated because of its medicinal effects on the immune system, blood pressure, and cancer. Major ginsenosides in fresh ginseng are converted to minor ginsenosides by structural changes such as hydrolysis and dehydration. The transformed ginsenosides are generally more bioavailable and bioactive than the primary ginsenosides. Therefore, in this study, hydrothermal processing was applied to ginseng preparation to increase the yields of the transformed ginsenosides, such as 20(S)-Rg3, Rk1, and Rg5, and enhance antioxidant activities in an effective way. MethodsGinseng extract was hydrothermally processed using batch reactors at 100–160°C with differing reaction times. Quantitative analysis of the ginsenoside yields was performed using HPLC, and the antioxidant activity was qualitatively analyzed by evaluating 2,2'-azino-bis radical cation scavenging, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and phenolic antioxidants. Red ginseng and sun ginseng were prepared by conventional steaming as the control group. ResultsUnlike steaming, the hydrothermal process was performed under homogeneous conditions. Chemical reaction, heat transfer, and mass transfer are generally more efficient in homogeneous reactions. Therefore, maximum yields for the hydrothermal process were 2.5–25 times higher than those for steaming, and the antioxidant activities showed 1.6–4-fold increases for the hydrothermal process. Moreover, the reaction time was decreased from 3 h to 15–35 min using hydrothermal processing. ConclusionTherefore, hydrothermal processing offers significant improvements over the conventional steaming process. In particular, at temperatures over 140°C, high yields of the transformed ginsenosides and increased antioxidant activities were obtained in tens of minutes.

Effect of hydrothermal process for inorganic alumina sol on crystal structure of alumina gel

This paper reports the effect of a hydrothermal process for alumina sol on the crystal structure of alumina gel derived from hydrothermally treated alumina sol to help push forward the development of low temperature synthesis of α-Al2O3. White precipitate of aluminum hydroxide was prepared with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution. The obtained aluminum hydroxide precipitate was peptized by using acetic acid at room temperature, which resulted in the production of a transparent alumina sol. The alumina sol was treated with a hydrothermal process and transformed into an alumina gel film by drying at room temperature. Crystallization of the alumina gel to α-Al2O3 with 900 °C annealing was dominant for a hydrothermal temperature of 100 °C and a hydrothermal time of 60 min, as production of diaspore-like species was promoted with the hydrothermal temperature and time. Excess treatments with hydrothermal processes at higher hydrothermal temperature for longer hydrothermal time prevented the alumina gel from being crystallized to α-Al2O3 because the excess hydrothermal treatments promoted production of boehmite.

Lithogeochemical Vectors for Hydrothermal Processes in the Strange Lake Peralkaline Granitic REE-Zr-Nb Deposit

Extreme enrichment and postmagmatic hydrothermal mobilization of the rare earth elements (REE), Zr, and Nb have been reported for a number of anorogenic peralkaline intrusions, including the world-class REE-Zr-Nb deposit at Strange Lake, Quebec, Canada. Establishing lithogeochemical vectors for these types of deposits is a challenging task because the effects of hydrothermal processes on element distribution are poorly known and the relationships of alteration types to mineralization stages have not been well documented. Here, we present results of a detailed mineralogical and geochemical investigation involving a dataset of over 500 mineral and bulk-rock analyses of a northeast-southwest section through the potential ore zone at Strange Lake. Based on these data, we develop a model that explains the role of hydrothermal processes in concentrating metals in peralkaline granitic systems and identify lithogeochemical vectors for their exploration. The B zone, located along the northwestern margin of the Strange Lake pluton, contains a lens-shaped, pegmatite-rich domain comprising subhorizontal sheets of pegmatites hosted by granites with a total indicated resource of 278 million tonnes (Mt) grading 0.93 wt % total rare earth oxides (TREO), of which 39% are heavy rare earth elements (HREE). Within this resource, there is an enriched zone containing 20 Mt of ore grading 1.44 wt % TREO, of which 50% are HREE. The pegmatites are characterized by a core enriched in quartz, fluorite, and light rare earth elements (LREE) fluorocarbonates, and a granitic border enriched in zirconosilicates and granitic minerals. The pegmatite sheets and surrounding granites evolved in three essential stages: a magmatic stage (I), a near-neutral hydrothermal stage involving their interaction with NaCl-bearing orthomagmatic fluids (II), and an acidic hydrothermal stage (III, comprising high-[IIIa] and low-temperature [IIIb] substages) that resulted from their interaction with pegmatite-sourced HCl-HF–bearing fluids. Stage IIIa led to pseudomorphic mineral replacement reactions (e.g., Na-Ca exchange during replacement of zirconosilicates) and formation of an aegirinization/hematization halo around the pegmatites. In contrast, stage IIIb, which was responsible for the hydrothermal mobilization of Zr and REE, is manifested by fluorite and quartz veins, zircon spherules, gadolinite-group minerals, gittinsite, ferriallanite-(Ce), and a pervasive replacement of the granite by these minerals. The distribution of REE, Zr, Nb, and Ti was controlled by the competition between hydrothermal fluids and the stability of primary REE-F-(CO 2 ) minerals (e.g., bastnasite-(Ce) host to LREE), zirconosilicates (i.e., Na zirconosilicates and zircon host to HREE and Zr), and Nb-Ti minerals (i.e., pyrochlore host to Nb and narsarsukite host to Ti), and the stability of secondary LREE silicates (i.e., ferriallanite-(Ce)), HREE silicates (i.e., gadolinite-(Y)), zirconosilicates (i.e., gittinsite and zircon), and Nb-Ti minerals (i.e., titanite and pyrochlore). Lithogeochemical vectors were identified to distinguish between the high-temperature acidic alteration (IIIa), using CaO/Na 2 O (indicator of Ca metasomatism) and Fe 2 O 3 /Na 2 O ratios (indicator of aegirinization/hematization), and the low-temperature acidic alteration (IIIb), using the CaO/Al 2 O 3 ratio (indicator of Ca-F metasomatism). Bulk-rock compositional data show that alteration was accompanied by an enrichment in heavy rare earth oxides (HREO) and ZrO 2 at the deposit scale, whereas there was no selective enrichment in the light rare earth oxides (LREO). A 2-D geochemical model of the deposit indicates that the LREO are more dispersed, whereas HREO and ZrO 2 are selectively distributed. These variations in LREE/HREE are also reflected in the mineral chemistry, especially in hydrothermal zircon crystals showing an unusual LREE enrichment and HREE depletion, contrasting with pseudomorphs, which are enriched in HREE. Hydrothermal ferriallanite-(Ce) and gadolinite-group minerals also show a clear trend of REE depletion with Ca enrichment. Controlling factors for the hydrothermal mobilization of LREE, HREE, and Zr were temperature, pH, and the availability of fluoride ions (F − ) in the fluid for the dissolution of zircon, and chloride ions (Cl − ) for the complexation of the REE. The study of rare hydrothermal minerals in conjunction with field observations and the evaluation of variations in bulk-rock composition allowed us to develop a new model for the hydrothermal evolution stage of Strange Lake.

Tailoring the properties of palygorskite by various organic acids via a one-pot hydrothermal process: A comparative study for removal of toxic dyes

Naturally abundant palygorskite (PAL) has been frequently used as an efficient, stable, low cost and environment-benign adsorbent to remove toxic pollutants for alleviating their harm to human health. However, the adsorption capacity of natural PAL is limited, which restricts its applications as an efficient adsorbent. As the aim to improve the adsorption capability of natural PAL and develop a high-efficient silicate adsorbent, the organic acids with different structures (i.e., acetic acid, glycolic acid, glycine, chloroacetic acid, benzoic acid, oxalic acid and citric acid) were employed to modify natural PAL via a simple one-step hydrothermal process. The effect of hydrothermal process in the presence of organic acids on the microscopic structure, physico-chemical features and adsorption properties of the PAL-derived adsorbent was studied comparatively using the dyes methylene blue (MB), methyl violet (MV) and malachite green (MG) as the model pollutants. It was found that the structural evolution of PAL and the introduction of functional groups positively contribute to improve the adsorption capacity. The PAL-derived adsorbents in the presence of chloroacetic acid (CAA-PAL) and citric acid (CA-PAL) show excellent adsorption capacity, which could almost completely remove the MB, MV and MG dyes from 200mg/L of the solution, but the raw PAL can only remove 59% (for MB), 63% (for MV) and 88% (for MG). The intensified electrostatic attraction, hydrogen-bonding interaction and chemical association of –Si–O− groups with dyes, resulting from the hydrothermal evolution of PAL crystal, are primarily responsible for the enhancement of adsorption capacity.

Effect of hydrothermal processing on total polyphenolics and antioxidant potential of underutilized leafy vegetables, Boerhaavia diffusa and Portulaca oleracea

To investigate the effect of different processing methods on antioxidant properties of acetone extract of aerial parts from Boerhaavia diffusa and Portulaca oleracea. The total phenolic and flavonoid contents were determined by Folin-Ciocalteau and aluminum chloride method, respectively. FRAP, metal chelating activity, DPPH, ABTS, nitric oxide, hydroxyl and superoxide radical scavenging activities, carotene/linoleic acid bleaching activity were used for the determination of antioxidant capacity. The total phenolics in Boerhaavia diffusa (82.79-162.80 mg GAE/g extract) were found to be higher when compared to that of Portulaca oleracea (22.94-10.02 mg GAE/g extract). Hydrothermal processing enhanced the level of inhibition on synthetic radicals such as DPPH (3 439-309 549 mmol TE/g extract) and ABTS (17 808-53 818 mmol TE/g extract) as well as biologically relevant radicals such as superoxide anion (70%-90%) and nitric oxide (49%-57%). In addition, boiling of the vegetables were found to be maximum capacity of FRAP (6 404.95 mmol Fe (II)/g extract) and metal chelating activity (1.53 mg EDTA/g extract) than the respective raw samples. The present investigation suggests that the processing enhance the functionality and improves the availability of bioactive substances of these vegetables. In addition, they also exhibited more potent antioxidant activity. Therefore these natural weeds from the crop land ecosystem could be suggested as cost effective indigenous green vegetables for human diet and potential feed resources for animals. Further extensive studies on role and importance of those weeds in sustaining the agro biodiversity are also needed.

Effects of hydrothermal processes on antioxidants in brown, purple and red bran whole grain rice (Oryza sativa L.)

The impacts of parboiling and wet-cooking, alone and in combination, on the concentrations of lipophilic antioxidants (vitamin E and γ-oryzanol), soluble (including proanthocyanidins and anthocyanins) and cell wall-bound phenolics, and antioxidant capacities in whole grain rice from six cultivars having different bran colours were investigated. Parboiling rough and brown rice increased the concentrations of lipophilic antioxidants in whole grain rice but decreased the concentrations of total phenolics and antioxidant capacities found in the soluble fraction. After hydrothermal processing of purple bran rice, the retention of extractable anthocyanins was low, but was high for simple phenolics. For proanthocyanidins found in red bran rice, the extractable oligomers with a degree of polymerization (DP) less than 4, increased up to 6-fold; while for oligomers with DP⩾4 and polymers, there was a significant decrease that was positively correlated with the DP and the temperature of the processing methods. The presence of hulls helped to retain water-soluble antioxidants during parboiling.

Synthesis of porous silica hollow spheres using sacrificial template for drug delivery applications

Article history: Received January 22, 2014 Received in revised form February 02, 2014 Accepted 8 May 2014 Available online 30 May 2014 In this work, we report on the synthesis of SiO2 hollow spheres using carbon nanospheres as the sacrificial template by hydrothermal method. The synthesized substrates are in a spherical morphology and uniform size distribution. The effects of hydrothermal process, concentration and the reaction temperature were optimized during synthesis of carbon nanospheres. Infrared spectroscopy (IR), and scanning electronic microscopy (SEM) methods were used for identification of the synthesized products. The synthesized SiO2 nanospheres were used as drug carrier to investigate in vitro release behavior of monoterpenic phenol isomers, carvacrol and thymol, in simulated body fluid (SBF). Ultraviolet-visible spectroscopy (UV-vis) method was carried out to determine the amount of the drugs entrapped in the carrier. The results indicated that SiO2 nanospheres have high ability to adsorb the drugs and there is no need for adjusting the pH during the adsorption process. The drug release profile shows a three stages pattern and indicates a delayed release action. © 2014 Growing Science Ltd. All rights reserved.

Effects of Hydrothermal Process on the Nutrient Release of Sewage Sludge

Hydrothermal treatment has demonstrated the ability of improving the dehydration and drying performances of sewage sludge, as well as shown its suitability for producing fuel. On the other hand, because of the abundant nutrient matters in sewage sludge, the produced liquid may be used as the liquid organic fertilizer. In this work, the effect of the hydrothermal treatment on the nutrient behavior in sewage sludge was investigated. The effects of the reaction temperature (180-240°C), and the reaction time (30-90 min) were investigated, and both of solid and liquid products were analyzed individually. The results showed that 40%-70% of nitrogen, 50%-70% of potassium and 10%-15% of phosphorus in sewage sludge could be dissolved into the liquid product, and that the solubilization was highly influenced by the temperature and the reaction time during the hydrothermal process. The hydrothermal treatment can effectively transport nutrient components in sewage sludge into the liquid product.

Effect of Hydrothermal Process on Xonotlite Crystal

Effect of hydrothermal process on xonotlite crystal prepared from K2SiO3 and H2SiO3 respectively in CaO-SiO2-H2O system was researched in this paper. The crystal phase composition and morphology of the xonotlite crystal were analyzed using XRD and techniques. The results indicate that different hydrothermal process poses significant impact on the microstructure of xonotlite crystal. The xonotlite spherical particle with the diameter of 10-20 µm was prepared from H2SiO3 only via dynamic hydrothermal process. The xonotlite whisker prepared from K2SiO3 with the length of 20-40 μm, diameter of 400 nm and the aspect ratio of 50-100 was successfully prepared from K2SiO3 via dynamic hydrothermal process, while with the length of 5-10 μm, diameter of 500 nm and the aspect ratio of 10-20 via static hydrothermal process.

Effect of hydrothermal processing on colour, antioxidant and free radical scavenging capacities of edible Irish brown seaweeds

SummaryThe effect of heat processing on change in colour (ΔE), level of bioactive compounds and overall antioxidant capacity in raw and heat‐processed edible Irish brown seaweeds was investigated. Raw seaweeds were heated at 85–121 °C for 15 min in an autoclave and extracted with 60% methanol. In comparison with raw seaweeds for all the species studied, heating increased total phenol (TPC) (1.6‐ to 1.9‐fold) and total tannin (TTC) (1.3‐ to 2.6‐fold) at 95 °C, while total flavonoid (TFC) (1.6‐ to 3.3‐fold) and total sugar (TSC) (1.9‐ to 4.3‐fold) at 85 °C. Similarly, EC50 value reduced in case of DPPH• scavenging (30.7–51.8%), metal chelating ability (FIC) (27–67.8%) and H2O2 scavenging capacity (13.3–16.1%) at 95 °C, while reduction in lipid peroxidation (10.8–31.5%) observed at 85 °C. Results showed that heating affects content of bioactive compounds as well as beneficial biological activity associated with these compounds, which can suggest new processing for application of seaweeds extract as nutraceutical.

Synthesis and luminescence properties of (Zn,Cd)S:Ag nanocrystals by hydrothermal method

ZnS:Ag and (Zn,Cd)S:Ag nanoparticles with particle sizes of about 50 and 150 nm have been prepared by hydrothermal method. The effects of hydrothermal process on the physical and luminescence characteristics are investigated. The photoluminescence intensities of hydrothermal treatment ZnS:Ag samples are 10 times higher than that of non-treated samples after annealing at 800°C.

Effects of Hydrothermal Process on Formation of Calcium Silicate Hydrates at 250°C

Effects of Hydrothermal Process on Formation of Calcium Silicate Hydrates at 250°C

Magmatic Precursors of Hydrothermal Fluids at the Rio Blanco Cu-Mo Deposit, Chile: Links to Silicate Magmas and Metal Transport

In most porphryr, systems the obscuring effects of hydrothermal processes and subsequent alteration, along with limited exposure of source rocks, preclude a detailed understanding of how and where metals and volatiles were derived. However, in this study we examine melt inclusions which have escaped alteration and that sampled all of the phases coexisting in the magma, in late- and postmineral rhyolitic units from the Rio Blanco Cu-Mo deposit, Chile. These inclusions demonstrate the existence of a volatile-rich melt, the exsolution from it of an aqueous volatile-rich phase, initially as melt + vapor bubble emulsions, and the disruption of these emulsions into melt and primary magmatic fluids. Trapping of these emulsions may explain the occurrence of melt inclusions containing widely, varying proportions of melt and aqueous fluid found at Rio Blanco. We demonstrate the sequestering of metals into the exsolved volatile phases and the derivation from these of possible ore-forming hydrothermal fluids, with particular reference to the implications for metal transport. Melt inclusions show differences between adjacent comagmatic intrusions that may be directly related to the extent of mineralization of the respective bodies. In one of the Rio Blanco postmineral rhyolite bodies melt inclusions show exsolution of the volatile-rich phase but only minor evidence of trapping of a metal-rich vapor. In contrast, inclusions from an adjacent late mineral rhyolite body show similar volatile phase exsolution but also provide evidence of ponding of metal-rich hydrothermal fluids during the final stages of cooling.

BUCHER, K. & FREY, M. 2002. Petrogenesis of Metamorphic Rocks, 7th ed. xvi + 341 pp. Berlin, Heidelberg, New York: Springer-Verlag. Price Euros 49.95 (+VAT at local rate), SFr 86.00, £35.00, US $59.95 (hard covers). ISBN 3 540 43130 6

BUCHER, K. & FREY, M. 2002. Petrogenesis of Metamorphic Rocks, 7th ed. xvi + 341 pp. Berlin, Heidelberg, New York: Springer-Verlag. Price Euros 49.95 (+VAT at local rate), SFr 86.00, £35.00, US $59.95 (hard covers). ISBN 3 540 43130 6 - Volume 140 Issue 5

Effect of hydrothermal processing on carrot carotenoids changes and interactions with dietary fiber.

The aim of the studies was to determine the effect of different methods of heat treatment on carotenoids changes and their interactions with insoluble and soluble dietary fiber. Three industrial varieties of carrot--Simba, Caropak and Fayette constituted the experimental material. Carrot cubes were subjected to heat treatment by putting in water with or without citric acid, or in a convection-type steam furnace. The total content of alpha- and beta-carotene was determined in all kinds of pureed carrots. Its amount bounded with insoluble dietary fiber and pectins was also determined. Changes in soluble and insoluble fractions of dietary fiber during hydrothermal treatment were also determined. It was found that the content of trans alpha- and beta-carotene in carrots decreased significantly (p < 0.05) after heat treatment, compared with the control sample. The loss observed during heat treatment in water was higher (up to 50%) than in the case of a convection-type steam furnace. The highest decrease in the content of insoluble fraction of dietary fiber and the highest increase in soluble fraction were observed after treatment with the use of steam. An analysis of interactions between carotenoids and dietary fiber fractions after hydrothermal processing shows their stronger affinity to forming bonds with pectins than with insoluble fiber. It was also found that the effect of heat treatment parameters was significant--the highest (by six times) increase in the content of beta-carotene bounded with pectins was noted in pureed carrots processed in a convection-type steam furnace.

Effects of hydrothermal processes on the chemical and isotopic composition of mantle-derived gases in SE China

Chemical and isotopic (He, Ar and C) compositions have been measured for bubbling gases discharging from two closely-spaced earthquake prediction wells in Guangdong, SE China. Observed 3He/ 4He ratios ( R/ R A ranging from 1.1 to 4.9) indicate the occurrence of a mantle component that has been diluted by a crustal radiogenic 4He component. δ 3C values of CO 2 suggest a different origin in the two wells: magmatic for ZK#1 (−6.8 to −8.4%‰:) and biogenic for ZK#7 (−14.5 to −18.2%). Observed 40 Ar/ 36Ar and air-corrected N 2/Ar ratios suggest that nitrogen and argon of both wells are mostly meteoric. While the CO 2/ 3He ratios (∼1 x 109) in ZK#1 are close to that of MORB (Middle Oceanic Ridge Basalts), the ZK#7 is characterized by much lower CO 2/ 3He ratios (∼1 x10 7) with lower CO 2 concentration. The latter cannot be ascribed in terms of a simple mixing of the two components but has to be explained by removal of CO 2, probably caused by calcite precipitation. Alternatively, CO 2 removal from and 4He addition to the magmatic component may be responsible for the coupled variations of 3He/ 4He and CO 2/He ratios in the two wells, which is most likely controlled by the degree of gas-water-rock interaction.