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1.
Bull Earthq Eng ; 20(14): 7873-7905, 2022.
Article in English | MEDLINE | ID: mdl-35210981

ABSTRACT

On October 30th, 2020, a magnitude 7.0 earthquake offshore off the northern coast of Samos, Greece, generated a tsunami that impacted the nearshore Greek islands and the Aegean coastline of Turkey. Here, we describe detailed results from several post-event field surveys, and report first wave arrival timing and polarity information as well as tsunami height/runup measurements, from five islands. In Chios, wave runup reached 1.38 m, in Samos ~ 3 m, in Fourni 1.57 m, in Thimena 1.46 m, and in Ikaria 1.18 m. This event marks two milestones. One, the General Secretariat for Civil Protection of Greece, disseminated a message through Greece's 1-1-2 Emergency Communications Service to all cell phones in the eastern Aegean geographical region, warning recipients to stay away from coastal areas. According to eyewitnesses, the message was received ~ 3-5 min prior to the second and largest flood in Vathi, as the first flood had not sufficiently alarmed the local authorities to evacuate residents. Two, we were able to infer complete tsunami hydrographs from measurements for the first two floods in Vathi, which suggests that the water level rose to about one meter overland flow depth in one minute.

2.
J Food Sci Technol ; 56(3): 1438-1444, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30956323

ABSTRACT

UV-C (180-280 nm) has been shown to extend the postharvest shelf-life of many horticulture crops. In this study, Tahitian limes (Citrus latifolia) were exposed to 0, 3.4, 7.2 and 10.5 kJ m-2 UV-C then stored for 28 days in air at 10 °C and 80% RH. Weight loss, peel colour, calyx abscission, ethylene production, respiration rate, total soluble solids (TSS), titratable acidity (TA) and acceptability index were assessed. The results showed that UV-C treatment maintained lime peel green colour and retained calyx attachment after 28 days storage. UV-C treatment also affected endogenous ethylene production and respiration rate, where the highest UV-C treatment (10.5 kJ m-2) maintained low ethylene production and low respiration rates after 28 days storage with no differences between the different UV-C intensities. In terms of fruit acceptability, limes were exposed to 10.5 kJ m-2 UV-C had a 60% acceptability index after 28 days storage, while untreated control fruit retained acceptability of 39%. In general, the pre-storage UV-C treatments did not affect fruit weight loss, TSS or TA contents during storage.

3.
Int J Mol Sci ; 19(7)2018 Jul 02.
Article in English | MEDLINE | ID: mdl-30004416

ABSTRACT

Current chemotherapy drugs for pancreatic cancer only offer an increase in survival of up to six months. Additionally, they are highly toxic to normal tissues, drastically affecting the quality of life of patients. Therefore, the search for novel agents, which induce apoptosis in cancer cells while displaying limited toxicity towards normal cells, is paramount. The olive biophenols, oleuropein, hydroxytyrosol and tyrosol, have displayed cytotoxicity towards cancer cells without affecting non-tumorigenic cells in cancers of the breast and prostate. However, their activity in pancreatic cancer has not been investigated. Therefore, the aim of this study was to determine the anti-pancreatic cancer potential of oleuropein, hydroxytyrosol and tyrosol. Pancreatic cancer cells (MIA PaCa-2, BxPC-3, and CFPAC-1) and non-tumorigenic pancreas cells (HPDE) were treated with oleuropein, hydroxytyrosol and tyrosol to determine their effect on cell viability. Oleuropein displayed selective toxicity towards MIA PaCa-2 cells and hydroxytyrosol towards MIA PaCa-2 and HPDE cells. Subsequent analysis of Bcl-2 family proteins and caspase 3/7 activation determined that oleuropein and hydroxytyrosol induced apoptosis in MIA PaCa-2 cells, while oleuropein displayed a protective effect on HPDE cells. Gene expression analysis revealed putative mechanisms of action, which suggested that c-Jun and c-Fos are involved in oleuropein and hydroxytyrosol induced apoptosis of MIA PaCa-2 cells.


Subject(s)
Apoptosis/drug effects , Cell Cycle/drug effects , Iridoids/pharmacology , Olea/chemistry , Pancreatic Neoplasms/drug therapy , Phenylethyl Alcohol/analogs & derivatives , Apoptosis Regulatory Proteins/metabolism , Cell Line, Tumor , Humans , Iridoid Glucosides , Iridoids/chemistry , Neoplasm Proteins/metabolism , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , Phenylethyl Alcohol/chemistry , Phenylethyl Alcohol/pharmacology
4.
Foods ; 7(7)2018 Jul 19.
Article in English | MEDLINE | ID: mdl-30029543

ABSTRACT

The effect of different combinations of maltodextrin (MD) coating agents (MD, MD + soybean protein, and MD + ι-carrageenan) on the encapsulation of lemon by-product aqueous extracts using freeze-drying and spray-drying were investigated. The total phenolic content (TPC), total flavonoid content (TFC), and ferric ion reducing antioxidant power (FRAP) of the microparticles were evaluated. Freeze-drying with the mixture of MD + soybean protein resulted in the highest retention of TPC, TFC, and FRAP (1.66 ± 0.02 mg GAE/g d.b., 0.43 ± 0.02 mg CE/g d.b., and 3.70 ± 0.05 mM TE/g, respectively). Freeze-drying resulted in microparticles with lower moisture content (MC) and water activity (aw) than those produced by spray-drying. Specifically, the MC and aw of the microparticles produced by freeze-drying ranged from 1.15 to 2.15% and 0.13 to 0.14, respectively, while the MC and aw of the microparticles produced by spray-drying ranged from 6.06% to 6.60% and 0.33 to 0.40, respectively. Scanning electron microscopy revealed that spray-drying resulted in the formation of spherical particles of different sizes regardless of the type of coating agent. Although freeze-drying resulted in microparticles with amorphous glassy shapes, the mixture of MD + soybean protein resulted in the formation of spherical porous particles. X-ray diffraction revealed a low degree of crystallinity for the samples produced by both techniques.

5.
J Food Sci Technol ; 55(7): 2467-2475, 2018 Jul.
Article in English | MEDLINE | ID: mdl-30042562

ABSTRACT

The green Tahitian limes (Citrus latifolia) were exposed to 7.2 kJ m-2 UV-C and 0.5 µL L-1 1-methylcyclopropene (1-MCP) treatments both separately and in combination. After treatment, fruit were stored in ethylene free (i.e. air containing < 0.005 µL L-1) or 0.1 µL L-1 ethylene at 20 °C and 100% RH. The results showed that UV-C treatment delayed skin degreening and reduced endogenous ethylene production compared to untreated control fruit, however these effects reduced over the storage time. As expected, 1-MCP inhibited ethylene production, reduced calyx abscission and retained peel greenness during the storage. Both of the combination treatments, 1-MCP + UV-C and UV-C + 1-MCP reduced endogenous ethylene production and delayed skin yellowing. In all treatments, UV-C and 1-MCP resulted in lower fruit respiration rates than untreated control fruit, however this effect diminished during 7 and 14 days storage for fruits stored in air and 0.1 µL L-1 ethylene atmosphere, respectively. There was no difference in weight loss, SSC, TA and SSC/TA ratio between the treatments and storage conditions. The results suggest that a pre-storage UV-C treatment, followed by storage at low level of ethylene improves the quality of limes, with the additional improvement when combined with 1-MCP treatment prior or after UV-C irradiation.

6.
J Food Sci Technol ; 54(8): 2270-2278, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28740283

ABSTRACT

The aim of this study was to develop an optimal formulation for preparation of edible films from chitosan, pea starch and glycerol using response surface methodology. Three independent variables were assigned comprising chitosan (1-2%), pea starch (0.5-1.5%) and glycerol (0.5-1%) to design an empirical model best fit in physical, mechanical and barrier attributes. Impacts of independent variables on thickness, moisture content, solubility, tensile strength, elastic modulus, elongation at break and water vapor permeability of films were evaluated. All the parameters were found to have significant effects on physical and mechanical properties of film. The optimal formulation for preparation of edible film from chitosan, pea starch and glycerol was 1% chitosan, 1.5% pea starch and 0.5% glycerol. Edible films with good physical and mechanical properties can be prepared with this formulation and thus this formulation can be further applied for testing on coating for fruit and vegetables.

7.
Foods ; 6(6)2017 Jun 14.
Article in English | MEDLINE | ID: mdl-28613233

ABSTRACT

n/a.

8.
Int J Biol Macromol ; 104(Pt A): 345-359, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28606842

ABSTRACT

The influence of different plasticizers (glycols, sugars and polyols) on the moisture sorption, mechanical, physical, optical, and microstructure characteristics of pea starch-guar gum (PSGG) film was studied. All plasticizers formed homogeneous, transparent, and smooth films, while PEG-400 did not produce film with suitable characteristics. Fourier transform infrared (FTIR) spectroscopy results indicated some interaction between plasticizers and the polymers. Scanning electron microscopy (SEM) observations of the films presented surfaces without cracks, breaks, or openings which were indicator of the miscibility and compatibility of employed plasticizers with PSGG films. The results showed that the films containing plasticizers with higher functional groups had lower equilibrium moisture content at aw <0.4. In general, a reduction in tensile strength and Young's modulus and an increase in elongation at break were detected when molecular weight of plasticizers and relative humidity increased in all film formulations. Films plasticized with monosaccharide showed similar mechanical properties to those with sorbitol, but lower solubility and water vapour permeability (WVP), higher transparency and moisture content than the sorbitol-plasticized films. The most noticeable plasticization effect was exerted by following order: glycerol > EG > PG > xylitol > fructose > sorbitol > mannitol > galactose > glucose > sucrose > maltitol.


Subject(s)
Galactans/chemistry , Glycols/chemistry , Mannans/chemistry , Mechanical Phenomena , Pisum sativum/chemistry , Plant Gums/chemistry , Starch/chemistry , Sugars/chemistry , Optical Phenomena , Solubility , Water/chemistry
9.
Foods ; 5(3)2016 Aug 23.
Article in English | MEDLINE | ID: mdl-28231150

ABSTRACT

Several studies have shown that UV-C (ultraviolet C) irradiation promotes the bioactive compounds and antioxidants of fresh fruits and vegetables. The aim of this study was to apply UV irradiation in dried lemon pomace powder for enhancing its phenolic content and antioxidant properties, thus more bioactive compounds should be available for extraction and utilization. Lemon pomace dried powder was placed under a UV lamp and treated with dosages of 4, 19, 80 and 185 kJ·m-2, while untreated powder was used as a control. UV-C irradiation significantly affected the total phenolic content, total flavonoid content, proanthocyanidins, and antioxidant capacity measured by cupric reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) of the lemon pomace dried powder, while it did not affect the vitamin C content. UV-C irradiation of 19 kJ·m-2 resulted in 19% higher total phenolic content than the control, while UV-C irradiation of 180 kJ·m-2 resulted in 28% higher total flavonoid content than the control. The antioxidant capacity was reduced when UV-C irradiation more than 4 kJ·m-2 was applied. The results of this study indicate that UV-C treatment has the potential to increase the extraction of bioactive compounds of dried lemon pomace at relatively high dosages.

10.
Molecules ; 20(7): 12992-3004, 2015 Jul 17.
Article in English | MEDLINE | ID: mdl-26193251

ABSTRACT

Olea europaea L. leaves are an agricultural waste product with a high concentration of phenolic compounds; especially oleuropein. Oleuropein has been shown to exhibit anti-proliferative activity against a number of cancer types. However, they have not been tested against pancreatic cancer, the fifth leading cause of cancer related death in Western countries. Therefore, water, 50% ethanol and 50% methanol extracts of Corregiola and Frantoio variety Olea europaea L. leaves were investigated for their total phenolic compounds, total flavonoids and oleuropein content, antioxidant capacity and anti-proliferative activity against MiaPaCa-2 pancreatic cancer cells. The extracts only had slight differences in their phytochemical properties, and at 100 and 200 µg/mL, all decreased the viability of the pancreatic cancer cells relative to controls. At 50 µg/mL, the water extract from the Corregiola leaves exhibited the highest anti-proliferative activity with the effect possibly due to early eluting HPLC peaks. For this reason, olive leaf extracts warrant further investigation into their potential anti-pancreatic cancer benefits.


Subject(s)
Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Olea/chemistry , Pancreatic Neoplasms/drug therapy , Plant Extracts/chemistry , Plant Extracts/pharmacology , Antineoplastic Agents/isolation & purification , Antioxidants/chemistry , Antioxidants/isolation & purification , Antioxidants/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Flavonoids/chemistry , Flavonoids/isolation & purification , Flavonoids/pharmacology , Humans , Iridoid Glucosides , Iridoids/chemistry , Pancreatic Neoplasms/pathology , Phenols/chemistry , Phenols/isolation & purification , Phenols/pharmacology , Plant Extracts/isolation & purification , Plant Leaves/chemistry
11.
Foods ; 5(1)2015 Dec 24.
Article in English | MEDLINE | ID: mdl-28231096

ABSTRACT

The moisture sorption isotherm of pea starch films prepared with various glycerol contents as plasticizer was investigated at different storage relative humidities (11%-96% RH) and at 5 ± 1, 15 ± 1, 25 ± 1 and 40 ± 1 °C by using gravimetric method. The results showed that the equilibrium moisture content of all films increased substantially above aw = 0.6. Films plasticized with glycerol, under all temperatures and RH conditions (11%-96%), adsorbed more moisture resulting in higher equilibrium moisture contents. Reduction of the temperature enhanced the equilibrium moisture content and monolayer water of the films. The obtained experimental data were fitted to different models including two-parameter equations (Oswin, Henderson, Brunauer-Emmitt-Teller (BET), Flory-Huggins, and Iglesias-Chirife), three-parameter equations Guggenhiem-Anderson-deBoer (GAB), Ferro-Fontan, and Lewicki) and a four-parameter equation (Peleg). The three-parameter Lewicki model was found to be the best-fitted model for representing the experimental data within the studied temperatures and whole range of relative humidities (11%-98%). Addition of glycerol increased the net isosteric heat of moisture sorption of pea starch film. The results provide important information with estimating of stability and functional characteristics of the films in various environments.

12.
J Food Sci ; 79(7): E1372-81, 2014 Jul.
Article in English | MEDLINE | ID: mdl-25041538

ABSTRACT

UNLABELLED: Bitter melon, Momordica charantia L. (Cucurbitaceae), aqueous extracts are proposed to have health-promoting properties due to their content of saponins and their antioxidant activity. However, the optimal conditions for the aqueous extraction of saponins from bitter melon and the effects of spray drying have not been established. Therefore, this study aimed to optimize the aqueous extraction of the saponins from bitter melon, using response surface methodology, prepare a powder using spray drying, and compare the powder's physical properties, components, and antioxidant capacity with aqueous and ethanol freeze-dried bitter melon powders and a commercial powder. The optimal aqueous extraction conditions were determined to be 40 °C for 15 min and the water-to-sample ratio was chosen to be 20:1 mL/g. For many of its physical properties, components, and antioxidant capacity, the aqueous spray-dried powder was comparable to the aqueous and ethanol freeze-dried bitter melon powders and the commercial powder. The optimal conditions for the aqueous extraction of saponins from bitter melon followed by spray drying gave a high quality powder in terms of saponins and antioxidant activity. PRACTICAL APPLICATION: This study highlights that bitter melon is a rich source of saponin compounds and their associated antioxidant activities, which may provide health benefits. The findings of the current study will help with the development of extraction and drying technologies for the preparation of a saponin-enriched powdered extract from bitter melon. The powdered extract may have potential as a nutraceutical supplement or as a value-added ingredient for incorporation into functional foods.


Subject(s)
Chemical Fractionation/methods , Momordica charantia/chemistry , Saponins/chemistry , Antioxidants , Dietary Supplements , Freeze Drying , Plant Extracts , Powders , Water
13.
Antioxidants (Basel) ; 3(4): 700-12, 2014 Oct 23.
Article in English | MEDLINE | ID: mdl-26785235

ABSTRACT

Olive leaves are an agricultural waste of the olive-oil industry representing up to 10% of the dry weight arriving at olive mills. Disposal of this waste adds additional expense to farmers. Olive leaves have been shown to have a high concentration of phenolic compounds. In an attempt to utilize this waste product for phenolic compounds, we optimized their extraction using water-a "green" extraction solvent that has not yet been investigated for this purpose. Experiments were carried out according to a Box Behnken design, and the best possible combination of temperature, extraction time and sample-to-solvent ratio for the extraction of phenolic compounds with a high antioxidant activity was obtained using RSM; the optimal conditions for the highest yield of phenolic compounds was 90 °C for 70 min at a sample-to-solvent ratio of 1:100 g/mL; however, at 1:60 g/mL, we retained 80% of the total phenolic compounds and maximized antioxidant capacity. Therefore the sample-to-solvent ratio of 1:60 was chosen as optimal and used for further validation. The validation test fell inside the confidence range indicated by the RSM output; hence, the statistical model was trusted. The proposed method is inexpensive, easily up-scaled to industry and shows potential as an additional source of income for olive growers.

14.
J Sci Food Agric ; 94(9): 1896-903, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24302224

ABSTRACT

BACKGROUND: Bitter melon (Momordica charantia L.) is a medicinal fruit reported to have antidiabetic properties. To grow this tropical fruit year-round in temperate climates, greenhouse production is necessary, sometimes without insect pollinators. Suitable high-yielding varieties with good bioactivity need to be identified. This experiment evaluated the yield of six varieties of bitter melon under greenhouse conditions and their bioactivity in terms of total phenolic and saponin compounds and total antioxidant activity determined using four assays. RESULTS: The larger varieties (Big Top Medium, Hanuman, Jade and White) were more productive than the small varieties (Indra and Niddhi) in terms of total fruit weight and yield per flower pollinated. The bioactivity (total phenolic and saponin compounds and antioxidant activity) of the two small varieties and Big Top Medium was significantly higher than that of the other three large varieties. Two antioxidant assays, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP), were shown to provide the strongest correlations with phenolic and saponin compounds of bitter melon. CONCLUSION: Preliminary research has identified Big Top Medium as the most suitable variety for greenhouse production. The rich source of phenolic and saponin compounds and their associated antioxidant activity highlight bitter melon as a valuable food.


Subject(s)
Agriculture/methods , Antioxidants/pharmacology , Biomass , Fruit/metabolism , Momordica charantia/metabolism , Phenols/pharmacology , Saponins/pharmacology , Antioxidants/metabolism , Biphenyl Compounds/metabolism , Climate , Fruit/growth & development , Fruit/standards , Humans , Momordica charantia/classification , Momordica charantia/growth & development , Phenols/metabolism , Picrates/metabolism , Saponins/metabolism , Species Specificity
15.
Aquat Toxicol ; 144-145: 116-23, 2013 Nov 15.
Article in English | MEDLINE | ID: mdl-24177214

ABSTRACT

Extreme environments may support communities of microalgae living at the limits of their tolerance. It is usually assumed that these extreme environments are inhabited by extremophile species. However, global anthropogenic environmental changes are generating new extreme environments, such as mining-effluent pools of residual waters from uranium mining with high U levels, acidity and radioactivity in Salamanca (Spain). Certain microalgal species have rapidly adapted to these extreme waters (uranium mining in this area began in 1960). Experiments have demonstrated that physiological acclimatisation would be unable to achieve adaptation. In contrast, rapid genetic adaptation was observed in waters ostensibly lethal to microalgae by means of rare spontaneous mutations that occurred prior to the exposure to effluent waters from uranium mining. However, adaptation to the most extreme conditions was only possible after recombination through sexual mating because adaptation requires more than one mutation. Microalgae living in extreme environments could be the descendants of pre-selective mutants that confer significant adaptive value to extreme contamination. These "lucky mutants" could allow for the evolutionary rescue of populations faced with rapid environmental change.


Subject(s)
Adaptation, Physiological , Microalgae/drug effects , Mining , Uranium/toxicity , Wastewater/toxicity , Water Pollutants, Chemical/toxicity , Adaptation, Physiological/genetics , Microalgae/genetics , Microalgae/growth & development , Mutation , Spain , Time
16.
J Sci Food Agric ; 93(8): 2022-7, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23254477

ABSTRACT

BACKGROUND: The aim of this experiment was to select a pool of potential red/pink natural colour candidates and evaluate their stability during ultrahigh-temperature (UHT) processing and subsequent storage and to compare their behaviour against the artificial colour erythrosine. It was hypothesised that heat processing and post-treatment storage conditions would have a negative effect on the stability of the natural colourants. RESULTS: All colourants except fermented red rice showed significant colour loss post-UHT processing (α=0.05). Analysis of the colour parameters L*, a* and b* determined that lycopene was the least stable of the colourants and red radish the most stable under all conditions. Fermented red rice was observed to be heat-stable after exposure to UHT processing and also remained relatively stable during storage, as was black carrot. The variation across trials and the spoilage of some samples were attributed to the fluctuations in temperature (±5 °C) observed during processing. CONCLUSION: Heat processing and post-treatment storage conditions had a negative effect on the stability of the natural colourants.


Subject(s)
Food Coloring Agents/chemistry , Hot Temperature , Erythrosine/chemistry , Fermentation , Food Handling/methods , Food Storage , Hydrogen-Ion Concentration , Oryza
17.
J Forensic Leg Med ; 19(5): 297-301, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22687773

ABSTRACT

We report an autopsy case of a 42-year-old woman who, when discovered, had been dead in her apartment for approximately 1 week under circumstances involving treachery, assault and possible drug overdose. This case is unique as it involved two autopsies of the deceased by two different medical examiners who reached opposing conclusions. The first autopsy was performed about 10 days after death. The second autopsy was performed after an exhumation approximately 2 years after burial. Evidence collected at the crime scene included blood samples from which DNA was extracted and analysed, fingerprints and clothing containing dried body fluids. The conclusion of the first autopsy was accidental death due to cocaine toxicity; the conclusion of the second autopsy was death due to homicide given the totality of evidence. Suspects 1 and 2 were linked to the death of the victim by physical evidence and suspect 3 was linked by testimony. Suspect 1 received life in prison, and suspects 2 and 3 received 45 and 20 years in prison, respectively. This case indicates that cocaine toxicity is difficult to determine in putrefied tissue and that exhumations can be important in collecting forensic information. It further reveals that the combined findings of medical examiners, even though contradictory, are useful in determining the circumstances leading to death in criminal justice. Thus, this report demonstrates that such criminal circumstances require comparative forensic review and, in such cases, scientific conclusions can be difficult.


Subject(s)
Exhumation , Homicide , Adult , Blood Stains , Cocaine/analysis , Contusions/pathology , DNA/isolation & purification , Dermatoglyphics , Female , Forensic Pathology , Gas Chromatography-Mass Spectrometry , Humans , Lacerations/pathology , Narcotics/analysis , Nasal Bone/injuries , Nasal Bone/pathology , Orbital Fractures/pathology , Polymerase Chain Reaction , Skull Fractures/pathology
18.
J Sep Sci ; 34(21): 3099-106, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21905216

ABSTRACT

Six different factors involved in the extraction of catechins from green tea using water were examined for their impact on the yield of catechins and on the efficiency of water use. The best temperature and time combination for catechin extraction was at 80°C for 30 min. The yield of catechins was also optimal with a tea particle size of 1 mm, a brewing solution pH <6 and a tea-to-water ratio at 50:1 (mL/g). In terms of efficient use of water in a single extraction, a water-to-tea ratio of 20:1 (mL/g) gave the best results; 2.5 times less water was used per gram of green tea. At the water-to-tea ratio of 20:1 mL/g, the highest yield of catechins per gram of green tea was achieved by extracting the same sample of green tea twice. However, for the most efficient use of water, the best extraction was found to be once at a water-to-tea ratio of 12:1 (mL/g) and once at a water-to-tea ratio of 8:1 (mL/g). Therefore, all six of the factors investigated had an impact on the yield of catechins extracted from green tea using water and two had an impact on the efficiency of water use.


Subject(s)
Catechin/isolation & purification , Hot Temperature , Plant Extracts/chemistry , Tea/chemistry , Water/chemistry
19.
J Sep Sci ; 34(18): 2468-74, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21735551

ABSTRACT

Theanine is a unique non-protein amino acid found in tea (Camellia sinensis). It contributes to the favourable umami taste of tea and is linked to various beneficial effects in humans. There is an increasing interest in theanine as an important component of tea, as an ingredient for novel functional foods and as a dietary supplement. Therefore, optimal conditions for extracting theanine from tea are required for the accurate quantification of theanine in tea and as an efficient first step for its purification. This study examined the effects of four different extraction conditions on the yield of theanine from green tea using water and applied response surface methodology to further optimise the extraction conditions. The results showed that temperature, extraction time, ratio of water-to-tea and tea particle sizes had significant impacts on the extraction yield of theanine. The optimal conditions for extracting theanine from green tea using water were found to be extraction at 80 °C for 30 min with a water-to-tea ratio of 20:1 mL/g and a tea particle size of 0.5-1 mm.


Subject(s)
Camellia sinensis/chemistry , Glutamates/isolation & purification , Tea/chemistry , Water/chemistry , Molecular Conformation , Particle Size , Surface Properties , Temperature , Time Factors
20.
New Phytol ; 188(2): 478-87, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20630023

ABSTRACT

• Investigating the differential capacity of the response of phytoplankton to human-induced environmental forcing has become a key issue to understanding further the future repercussions on the functioning of aquatic ecosystems. • The initial tolerance to the widely dispersed herbicide simazine was measured in diverse phytoplankton species. An experimental ratchet system maintaining large populations of dividing cells (which ensures the occurrence of rare spontaneous mutations that confer adaptation) and a strong selection pressure (which ensures the preservation of such mutations within the population) was later applied to estimate the capability of different groups of phytoplankton to adapt to simazine. • Initially, simazine doses between 0.05 and 0.15 ppm were able to inhibit 100% growth in all the species tested. However, a significant increase in simazine resistance was achieved in all derived populations during the ratchet experiment. The differential capacity for simazine adaptation was observed among the different species. • The capacity of different species to adapt to simazine can be explained in relation to taxonomic group, ploidy, growth rate and habitat preference. Haploid populations of continental Chlorophyta showed the greatest capacity to adapt to simazine. By contrast, populations of Haptophyta of open ocean regions were the group least capable of adapting to the herbicide.


Subject(s)
Adaptation, Physiological/drug effects , Herbicides/toxicity , Phytoplankton/drug effects , Simazine/toxicity , Water Pollutants, Chemical/toxicity , Cyanobacteria/drug effects , Cyanobacteria/growth & development , Phytoplankton/growth & development , Seawater , Species Specificity , Time Factors
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