[Show abstract][Hide abstract] ABSTRACT: The effect of a novel nano-packing material on preservation quality of Chinese jujube (Ziziphus jujuba Mill. var. inermis (Bunge) Rehd) during room temperature storage was investigated. The nano-packing material with lower relative humidity, oxygen transmission rate and high longitudinal strength (2.05 g/m2 24 h, 12.56 cm3/m2 24 h 0.1 MPa and 40.16 MPa, respectively) was synthesized by blending polyethylene with nano-powder (nano-Ag, kaolin, anatase TiO2, rutile TiO2). The results showed that the nano-packing material had a quite beneficial effect on physicochemical and sensory quality compared with normal packing material. After 12-day storage, fruit softening, weight loss, browning and climatic evolution of nano-packing were significantly inhibited. Meanwhile, the contents of titrable acid and ascorbic acid were decreased to 0.21%, 251 mg/100 g, for nano-packing and 0.15%, 198 mg/100 g, for normal packing; The contents of total soluble sugar, reducing sugar, total soluble solids and malondialdehyde were increased to 28.4%, 5.2%, 19.5% and 98.9 μmol/g for nano-packing and 30.0%, 6.3%, 23.1% and 149 μmol/g for normal packing. Therefore, the nano-packing could be applied for preservation of Chinese jujube to expand its shelf life and improve preservation quality.
[Show abstract][Hide abstract] ABSTRACT: The anticlastogenic effect of micrometer powder of selenium-enriched green tea (MSTP) was evaluated by using a chromosomal aberration assay in mouse testicular cells. Animals fed with a Se-deficient diet were treated with MSTP, micrometer powder of regular green tea (MRTP), selenite, and MRTP + selenite for 30 days by an intragastric route, followed by treatment of mitomycin C (MMC) on day 19 through intraperitoneal injection (ip). Selenium status and antioxidant enzymes were measured. Results indicated that MSTP showed a significant capability to reduce the incidence of MMC-induced chromosomal aberrations in spermatocytes from 22.7% to 6.7%. This inhibitory was highest, for MSTP, at 73.1%, while it was only 38.4% for MRTP. After 30 days of a Se-deficient diet, mice, either with or without the MMC treatment, showed a lower selenium concentration in blood and liver as well as lower enzyme activity of the antioxidants, GPx and SOD. Supplementation with MSTP, selenite, or selenite + MRTP enhanced the activities of these antioxidant enzymes. This enhancement was accompanied with a concomitant elevation of selenium levels, which favored the synthesis of the seleno-enzyme GPx and protected the cells from the MMC-induced oxidative stress. Our results indicate that MSTP is both able to prevent the chromosomal aberrations induced by MMC in mouse spermatocytes and to enhance GPx and SOD activity in blood serum and liver.
No preview · Article · May 2009 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: Previously, the antioxidant activity of Se-enriched green tea extracts has been studied in vitro. In the present study, an in vivo micronuclei test was employed to assess the antimutagenic effect of microsized Se-enriched green tea powder (MSTP) in mice bone marrow. Pretreatments of MSTP, micrometer-sized regular tea powder (MRTP), selenite, and MRTP + selenite were given by gavage for 29 consecutive days prior to cyclophoshamide (CP) treatment. Certain key antioxidant enzymes were also investigated to elucidate the mechanism of antimutagenic effect. Results indicated that MSTP and MRTP or selenite alone did not significantly induce micronuclei at either concentration, confirming its nonmutagenicity. In the CP-treated groups, significant suppressions in the micronuclei were recorded following pretreatment with MSTP, MRTP, and selenite administration. The antimutagenic effect of MSTP was evidently observed by significant reduction in the frequencies of micronuclei in bone marrow cells when compared to a positive control group. The administration of MSTP, selenite, and MRTP + selenite also increased the levels of selenium concentration, glutathione peroxidase (GPx), and superoxide dismutase (SOD) enzymes in both blood and liver. However, no pronounced differences in activities of GPx and SOD were found among MSTP, selenite, and MRTP + selenite. The present findings demonstrate that the antimutagenic potential of MSTP could not be solely related to the enhancment of antioxidant enzymes of GPx and SOD.
No preview · Article · Jun 2008 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: Ultrafiltration membranes of different pore size were applied to fractionate Chlorella pyrenoidosa polysaccharides (CPPS) and the main fraction could be separated by a membrane with nominal molecular weight cut-off (NMWCO) of 30 kDa. Ultrafiltration parameters of 40 °C 14.0 psi were optimized for obtaining the main fraction. The resulting sample was further purified by anion-exchange chromatography and size exclusion chromatography, and two distinctive polysaccharides, CPPS Ia and IIa were recovered. CPPS IIa had infrared spectral characteristic of polysaccharides similar to CPPS Ia, and the symmetrical stretching peak at 1408–1382 cm−1 was an indication of the presence of carboxyl groups. The peak molecular weights were 69658 Da and 109406 Da, for CPPS Ia and CPPS IIa, respectively. Both CPPS Ia and IIa were composed of rhamnose, mannose, glucose, galactose and an unknown monosaccharide. Galactose (relative mass 46.5%) was the predominant monosaccharide of CPPS Ia and in CPPS IIa, rhamnose (37.8%) was predominant. CPPS Ia and IIa presented significantly higher antitumor activity against A549 in vitro than did a blank control, in a dose-dependent manner. Both fractions might be useful for developing natural safe antitumor drugs from C. pyrenoidosa resources.
[Show abstract][Hide abstract] ABSTRACT: The crude tea polyphenols, polysaccharides and proteins of regular green tea and Se-enriched green tea were investigated in
vitro for antioxidant activities by auto-oxidation test (AAPH) and α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging
method. Results showed that crude tea polyphenols of Se-enriched green tea provided the highest antioxidant activity by DPPH
assay and the antioxidant activity was decreased in the order: crude tea polyphenols > crude tea proteins > tea polysaccharides.
The crude protein of Se-enriched green tea was found to exhibit the highest antioxidant activity by AAPH method and the antioxidant
activity was decreased in the order: crude tea proteins > tea polyphenols > tea polysaccharides. Tea polyphenols and tea polysaccharides
of Se-enriched green tea presented significantly higher antioxidant activities than that of regular green tea. No significant
difference of antioxidant activities was found between crude tea proteins of Se-enriched green tea and regular green tea.
The combinations of Se with tea polyphenols and tea polysaccharides were responsible for the higher antioxidant activities
of Se-enriched green tea than regular green tea.
Preview · Article · Jul 2007 · European Food Research and Technology
[Show abstract][Hide abstract] ABSTRACT: Yields and antioxidant activity of Chlorella pyrenoidosa extracts obtained by supercritical carbon dioxide extraction through an orthogonal experiment (L16(45)) were investigated to get the best extraction conditions. The results showed that extraction pressure, temperature and modifier were the main three variables that influenced the yields of extracts. The highest yield was obtained at 32°C, 40MPa, 20Lh−1 with dosage of modifier 1mL ethanolg−1 sample for 3h. Moreover, increasing pressure and concentrations of modifier led to the increase of extraction yields and antioxidant activity. DPPH radical scavenging method showed that almost all the extracts had significantly higher antiradical activities varying from 29.67±0.29% to 54.16±4.49% comparing to α-tocopherol, Trolox, and BHT as references except extracts at 32°C, 35MPa and 15Lh−1 without modifier for 1.5h. These results indicate that supercritical extraction is a promising alternative process for recovering compounds of high antioxidant activity from C. pyrenoidosa.
No preview · Article · Jun 2007 · Journal of Food Engineering
[Show abstract][Hide abstract] ABSTRACT: The effects of enzyme inactivation by microwave and oven heating were determined on the quality of tea harvested and stored in the spring and autumn tea processing season. The results indicated that both spring and autumn tea possessed by microwave heating had significantly higher vitamin C content and less loss during storage than that by oven heating. The absorbance of extracts of spring and autumn tea by microwave heating was higher than that by oven heating after several months’ storage, though lower for the first few months. The chlorophyll content of spring and autumn tea by microwave heating was higher and more stable than that by oven heating followed by storage, which indicated that microwave-heating treatment could reduce the decomposition of chlorophyll. The sensory quality was also higher in spring and autumn tea treated by microwave heating. However, no significant difference was found in the content of tea polyphenol between microwave and oven heating in spring and autumn tea. These results indicated that the preservation qualities of green tea harvested in spring and autumn were greatly enhanced by microwave heating.
Preview · Article · Jan 2007 · Journal of Food Engineering
[Show abstract][Hide abstract] ABSTRACT: The conditions for extracting and purifying polysaccharides from Chlorella pyrenoidosa, including intensity and duration of ultrasound, the temperature and incubation time, and ethanol concentration, were investigated through an orthogonal design of L16(45) in this work. High performance liquid chromatography (HPLC) and gas chromatography (GC) were used to characterize the compounds in C. pyrenoidosa. The highest yield of 44.8gkg−1 was achieved at 400W of ultrasound for 800s and then followed by incubation in water bath at 100°C for 4h in 80% ethanol. Two polysaccharide fractions (S1 and S2) were separated from the extracts of C. pyrenoidosa using Sepharose 4B column chromatography. The average molecular weights (Mw) of S1 and S2 were 81,877Da and 1749Da, respectively. Gas chromatographic (GC) traces of the hydrolyzed polysaccharides showed that most of the majority of monosaccharide in both fractions was mannose (78.0% and 76.5% of relative mass from S1 and S2, respectively) with low levels of glucose (13.2% and 8.4% of relative mass from S1 and S2, respectively). The Fourier-transform infrared spectra (FT-IR) of S1 and S2 revealed typical characteristics of polysaccharides. Both samples had the characteristics of hydroxyl groups, weak C–H band and α-pyranoses; however, only S2 had a carboxyl group.
[Show abstract][Hide abstract] ABSTRACT: Supercritical CO2 extraction of antioxidants from Spirulina platensis was optimized using response surface methodology. About 10.26 g/kg of extracts from S. platensis could be obtained under the optimum conditions of 48 °C at 20 MPa over a 4 h period. The antioxidant activity of the extracts prepared under the optimized condition, determined by linoleic acid peroxidation inhibition method, was lower compared with BHT and Trolox, but significantly higher than α-tocopherol in 300 min and became similar to α-tocopherol after that. The components of the extracts were further analyzed, and the results showed that the extracts contained 85.1 g/kg of flavonoids, 77.8 g/kg of β-carotene, 113.2 g/kg of vitamin A and 3.4 g/kg of α-tocopherol, which may contribute greatly to their high antioxidant activity. The main fatty acids in the extracts were palmitic acid (35.32%), linolenic acid (21.66%) and linoleic acid (20.58%).
[Show abstract][Hide abstract] ABSTRACT: The effects of polysaccharides from Chlorella pyrenoidosa on immunomodulatory activity were investigated in this paper. Phagocytosis of peritoneal macrophages was detected through ingesting chicken red blood cells (CRBC) test to evaluate nonspecific immune response. The cellular immune response was measured using the delayed-type hypersensitivity response to sheep red blood cells (SRBC) in terms of antibody titration level. Oral administration of C. pyrenoidosa polysaccharides, 1g and 2gkg−1 body weight significantly enhanced phagocytic rate (23.00 and 26.25%, respectively) and phagocytic index (0.30 and 0.36, respectively) compared with saline-treated control (P<0.05). The value of ear thickness rate was greatly elevated from 10.09% in saline-treated control to 16.22 and 19.48%, respectively in group treated with 1g and 2gkg−1 body weight polysaccharides (P<0.05). There was a significant correlation between the dosage of C. pyrenoidosa polysaccharides and antibody titre (r=0.99, P=0.019) and the antibody titre was significantly increased by 11.80, 21.90 as well as 39.80 in 2gkg−1 bw compared to 10.30 in the control. Dietary supplementation with C. pyrenoidosa polysaccharides did not affect the growth of the mice during the experiment. These results indicated that immunomodulatory activities in mice were enhanced by administration of polysaccharides derived from C. pyrenoidosa.
No preview · Article · Nov 2006 · European Food Research and Technology
[Show abstract][Hide abstract] ABSTRACT: Antioxidant activities of ethanol and petroleum ether extracts from Brazilian propolis were determined by α,α-diphenyl-β-picrylhydrazyl
(DPPH) radical-scavenging and ferric thiocyanate (FTC) methods, using α-tocopherol and butylated hydroxytoluene (BHT) as references.
The DPPH assay showed that ethanol extract possessed significantly higher activity compared with BHT and petroleum ether extract
but lower than that of α-tocopherol. Results from the FTC assay indicated that the activity of ethanol extract was higher
than that of α-tocopherol and petroleum ether extract but lower than BHT. Basically, this antioxidant activity was dose-dependent
and ethanol extract exhibited higher activity than that of petroleum ether extract at the same concentration. Additionally,
the chemical constituents of propolis were determined, and results showed that the propolis contained high content of antioxidant
compositions, such as flavonoids (73.00gkg−1), total phenolic compounds (134.40gkg−1), and Vitamin E (0.16gkg−1), which contributed greatly to its strong antioxidant activity.
No preview · Article · May 2006 · European Food Research and Technology