Structural and digestive characters of a heteropolysaccharide fraction from tea (Camellia sinensis L.) flower.

Tea (Camellia sinensis L.) flower polysaccharides (TFPS) have various health-promoting functions. In the present work, the structure of a purified TFPS fraction, namely TFPS-1-3p, and its in vitro digestive properties were investigated. The results demonstrated that TFPS-1-3p was a typical heteropolysaccharide consisting of rhamnose (Rha), arabinose (Ara), galactose (Gal) and galacturonic acid (GalA) with a molecular weight of 47.77 kDa. The backbone of TFPS-1-3p contained â†’ 4)-α-d-GalpA(-6-OMe)-(1 â†’ 4)-α-GalpA-(1 â†’ and â†’ 4)-α-d-GalpA(-6-OMe)-(1 â†’ 2,4)-α-l-Rhap-(1 â†’ linkages. The branch linkages in TFPS-1-3p contained â†’ 6)-ß-d-Galp-(1→, →3,6)-ß-d-Galp-(1→, →5)-α-l-Araf-(1 â†’ and â†’ 3,5)-α-l-Araf-(1 â†’. Subsequently, TFPS-1-3p could not be degraded under simulated human gastrointestinal conditions but could be of use to human fecal microbes, thereby lowering the pH and increasing the production of short-chain fatty acids (SCFAs) of the gut microenvironment and altering the composition of the gut microbiota. The relative abundance of Fusobacterium_mortiferum Megasphaera_elsdenii_DSM_20460, Bacteroides thetaiotaomicron, Bacteroides plebeius and Collinsella aerofaciens increased significantly, potentially contributing to the degradation of TFPS-1-3p.

Heat-induced tolerance to browning of fresh-cut lily bulbs (Lilium lancifolium Thunb.) under cold storage.

Fresh-cut lily bulbs were submerged in hot water at 50°C for 3 min as a condition of heat treatment (HT), and then stored at 4°C for 15 days to investigate the effects of HT on browning. Results showed that heat-treated samples exhibited lower browning degree and had reduced cell death rate and cell membrane permeability when compared to control samples during storage. HT resulted in a significant inhibition in total phenol content and the activities of phenylalanine ammonialyase, polyphenol oxidase, and peroxidase. HT also stimulated the activities of superoxide dismutase and catalase, however, inhibited lipoxygenase activity and malondialdehyde accumulation. Correlation analysis showed that lipid peroxidation of cell membrane was significantly correlated with browning of fresh-cut lily bulbs. The results indicated that HT could serve as an effective approach to retard browning of fresh-cut lily bulbs. PRACTICAL APPLICATIONS: The effect of heat treatment (HT) on fresh-cut lily bulbs by treating in hot water (50°C) for 3 min was investigated. It provided experimental basis for further studies of HT in extending the shelf life of fresh-cut lily bulbs. Furthermore, it is a foundation for the application of HT in the processing of fresh-cut lily bulbs. The results suggested that HT could be a promising method to inhibit browning and sustain the quality of fresh-cut lily bulbs.

Effect of Protocatechuic Acid-Grafted-Chitosan Coating on the Postharvest Quality of Pleurotus eryngii.

Protocatechuic acid-grafted-chitosan (PA-g-CS) solution with antioxidant activity was developed as a novel edible coating material for Pleurotus eryngii postharvest storage. The effect of PA-g-CS coating on the postharvest quality of P. eryngii was investigated by determination of various physicochemical parameters and enzyme activities. Results showed that the antioxidant capacity and viscosity of PA-g-CS solutions were closely related to the grafting degree and were much higher than that of chitosan (CS) solution. At the end of 15 days of storage, serious mushroom browning was observed in the control and CS coating groups. By contrast, PA-g-CS coating groups with medium and high grafting degrees maintained better physical appearance. Among all of the treatment groups, P. eryngii in PA-g-CS III coating group exhibited the highest firmness and the lowest weight loss, browning degree, respiration rate, malondialdehyde content, electrolyte leakage rate, superoxide anion production rate, and hydrogen peroxide content. Moreover, P. eryngii in PA-g-CS III coating group maintained relatively higher antioxidant enzyme activities but lower polyphenol oxidase activity than other treatment groups. Therefore, PA-g-CS III is a promising preservation agent for P. eryngii.

Protocatechuic acid grafted onto chitosan: Characterization and antioxidant activity.

In this study, protocatechuic acid (PA) was grafted onto chitosan (CS) by a carbodiimide mediated cross-linking reaction. The structural characterization, physical property and antioxidant activity of PA grafted CS (PA-g-CS) was investigated. As results, three copolymers with different grafting ratios (61.64, 190.11 and 279.69mg PAE/g) were obtained by varying the molar ratios of reaction substrates. PA-g-CS showed the same UV absorption peaks as PA at 258 and 292nm. As compared to CS, PA-g-CS exhibited a decreased band at 1596cm(-1) and a new band at 1716cm(-1), suggesting the formation of amide and ester linkages between PA and CS. New proton signals at δ6.77-7⋅33ppm were observed on (1)H NMR spectrum of PA-g-CS, assigning to the methine protons of PA. Signals at δ 150.8-116.6 ppm on (13)C NMR spectrum of PA-g-CS was assigned to the aromatic ring carbon of PA moieties. All the structural information confirmed the successful grafting of PA onto CS. SEM observation showed CS had a smooth surface, while PA-g-CS had a rough surface. TGA revealed the thermal stability of PA-g-CS was lower than CS. Antioxidant activity assays further verified the reducing power and DDPH radical scavenging activity of PA-g-CS was much higher than CS.

Structure, physical property and antioxidant activity of catechin grafted Tremella fuciformis polysaccharide.

In this study, structural characterization, physical property and antioxidant activity of catechin grafted Tremella fuciformis polysaccharide (catechin-g-TPS) were investigated. Crude polysaccharides were isolated from the fruit bodies of T. fuciformis and further purified on DEAE-52 and Sepharose CL-4B chromatography to afford a main purified fraction (named TPS). The molecular weight of TPS was determined as 5.82 × 10(5)Da by HPLC. Then, the free radical mediated grafting of catechin onto TPS was achieved by using a redox system. As compared with the unmodified TPS, catechin-g-TPS showed new bands within the range of 1300-1600 cm(-1) in FT-IR spectrum, and exhibited new signals at around δ 6.00 and 6.80 ppm in (1)H NMR spectrum. Thermogravimetric analysis indicated the thermal stability of catechin-g-TPS was higher than TPS. X-ray diffraction spectrum of catechin-g-TPS exhibited two sharp narrow diffraction peaks at 14.2 and 32.1°, corresponding to the crystalline peaks of catechin. Scanning electron microscopy observation revealed the surface of TPS was smooth, whereas the surface of catechin-g-TPS was much rough. These results all confirmed the successful grafting of catechin onto TPS. Moreover, catechin-g-TPS had higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power as compared to TPS.

Extraction, characterization and in vitro antioxidant activity of polysaccharides from black soybean.

Optimization of extraction conditions, preliminary characterization and in vitro antioxidant activity of polysaccharides from black soybean (BSPS) were investigated. The results of Box-Behnken design showed that the optimal extraction conditions for BSPS were as follows: ratio of water to material of 20 ml/g, extraction time of 6.4h and extraction temperature of 92 °C, with a corresponding yield of 2.56%. The crude BSPS were further fractionated on DEAE-52 and Sepharose CL-4B chromatography to afford three purified fractions (BSPS-1, BSPS-2 and BSPS-3). Chemical analysis showed that the three purified fractions were mainly composed of carbohydrate and uronic acid. In addition, BSPS-1 was composed of arabinose, rhamnose, galactose, glucose and mannose in the molar ratio of 1.79:1.00:2.59:26.54:1.01. BSPS-2 was composed of arabinose, rhamnose, xylose, galactose and mannose in the molar ratio of 8.10:4.80:9.15:13.38:1.00. BSPS-3 was composed of arabinose, rhamnose, galactose and mannose in the molar ratio of 16.80:3.60:33.66:1.00. The results of Fourier transform-infrared spectroscopy further confirmed the characteristic polysaccharide structures of the three purified fractions. Moreover, antioxidant assays showed crude BSPS and its purified fractions had potential superoxide anion and DPPH radical scavenging activities, and their antioxidant activity decreased in the order of crude BSPS > BSPS-3 > BSPS-2 > BSPS-1.

Structural characterization of two water-soluble polysaccharides from black soybean (Glycine max (L.) Merr.).

Black soybeans (Glycine max (L.) Merr.) have been widely used as a health food and medicinal herb in oriental medicine. In the present study, the chemical structures of two water-soluble polysaccharides (black soybean polysaccharide 1 (BSPS-1) and black soybean polysaccharide 3 (BSPS-3)) isolated from black soybeans were characterized by high performance size-exclusion chromatography (HPSEC), methylation analysis, and 1D (1H, 13C) and 2D (COSY, TOCSY, HSQC, NOESY, and HMBC) NMR spectra. The molecular weights of BSPS-1 and BSPS-3 were 1.95 × 105 and 1.88 × 105 Da, respectively. Methylation analysis and NMR spectra indicate that BSPS-1 is composed of 1,6-α-d-glucopyranosyl residues. By contrast, BSPS-3 is mainly composed of a 1,3-ß-d-galactopyranosyl residue backbone with side chains substituted at the O-6 position consisting of large content of T-α-l-Araf-(1→ residues, and small contents of →5)-α-l-Araf-(1→, →2)-α-l-Rhap-(1→, and 4-O-Me-ß-d-GlcAp-(1→ residues. Our results suggest that BSPS-1 is a linear (1→6)-α-d-glucan, whereas BSPS-3 is a type II arabinogalactan. The unique structures of BSPS-1 and BSPS-3 indicate that they might have wide applications in food and pharmaceutical industries.

Antioxidant and protective effect of inulin and catechin grafted inulin against CCl4-induced liver injury.

In this study, the antioxidant activity and hepatoprotective effect of inulin and catechin grafted inulin (catechin-g-inulin) against carbon tetrachloride (CCl4)-induced acute liver injury were investigated. Results showed that both inulin and catechin-g-inulin had moderate scavenging activity on superoxide radical, hydroxyl radical and H2O2, as well as lipid peroxidation inhibition effect. The antioxidant activity decreased in the order of Vc > catechin >catechin-g-inulin > inulin. Administration of inulin and catechin-g-inulin could significantly reduce the elevated levels of serum aspartate transaminase, alanine transaminase and alkaline phosphatase as compared to CCl4 treatment group. Moreover, inulin and catechin-g-inulin significantly increased the levels of hepatic superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione and total antioxidant capacity, whereas markedly decreased the malondialdehyde level when compared with CCl4 treatment group. Notably, catechin-g-inulin showed higher hepatoprotective effect than inulin. In addition, the hepatoprotective effect of catechin-g-inulin was comparable to positive standard of silymarin. Our results suggested that catechin-g-inulin had potent antioxidant activity and potential protective effect against CCl4-induced acute liver injury.

Free radical mediated grafting of chitosan with caffeic and ferulic acids: structures and antioxidant activity.

In this study, two water soluble chitosan derivatives were synthesized by grafting caffeic acid (CA) and ferulic acid (FA) onto chitosan via a free radical mediated method. The structural characterization, antioxidant activity in vitro and in vivo of chitosan derivatives were determined. Results showed that the UV-vis absorption peaks of chitosan derivatives shifted toward longer wavelengths. FT-IR spectroscopy exhibited the typical phenolic characteristics within 1450-1600 cm(-1). (1)H NMR spectroscopy showed new peaks of phenyl protons at 6.2-7.6 ppm. (13)C NMR spectroscopy showed additional peaks between 110 and 150 ppm assigned to the C=C of phenolic groups. These results all confirmed the successful grafting of CA and FA onto chitosan backbones. The chitosan derivatives had decreased thermal stability and crystallinity as compared to chitosan. In vitro assays showed that the antioxidant activity decreased in the order of CA-g-chitosan>FA-g-chitosan>chitosan. Moreover, administration of the chitosan derivatives could significantly increase antioxidant enzymes activities and decrease malondialdehyde levels in both serums and livers of d-galactose induced aging mice. Our results indicated the potential of CA-g-chitosan and FA-g-chitosan in the development of novel antioxidant agents.

Synthesis, characterization and in vitro anti-diabetic activity of catechin grafted inulin.

In this study, a novel biological macromolecule with strong in vitro anti-diabetic activity was developed by grafting catechin onto inulin via a free radical mediated method. The characterization, α-glucosidase and α-amylase inhibitory activities of catechin grafted inulin (catechin-g-inulin) were investigated. Results showed that the grafting ratio of catechin-g-inulin was 124.8 mg CAE/g. UV-vis spectrum of catechin-g-inulin exhibited a new band at 280 nm, attributing to B ring of catechin moiety. FT-IR spectrum of catechin-g-inulin showed new absorption bands between 1540 and 1418 cm(-1), attributing to CC stretching vibration of catechin moiety. (1)H NMR spectrum of catechin-g-inulin preserved all the characteristic proton signals of inulin and partial signals of catechin. These all confirmed the successful grafting copolymerization. Conjugation probably occurred between OH of inulin (C-6) and H-6/H-8 of catechin (A ring). Catechin-g-inulin also exhibited increased thermal stability and crystallinity as compared to inulin. Moreover, in vitro anti-diabetic assays showed the α-glucosidase inhibitory activity decreased in the order of catechin-g-inulin>catechin>acarbose>inulin, and α-amylase inhibitory activity decreased in the order of catechin-g-inulin>acarbose>catechin>inulin. These indicated the potential of catechin-g-inulin in the development of a novel effective anti-diabetic agent.

Synthesis of chitosan-gallic acid conjugate: structure characterization and in vitro anti-diabetic potential.

In this study, chitosan grafted copolymer with gallic acid (GA) was synthesized by a novel and efficient free radical mediated method. The optimal grafting conditions, structural characterization, α-glucosidase and α-amylase inhibitory activities of chitosan grafted copolymers were investigated. Results showed that the maximum grafting ratio (128.3 mg GA equivalents/g) was obtained at 12 h with 5 g/L chitosan, 16 g/L GA, 2 g/L ascorbic acid and 0.2 M hydrogen peroxide. UV-vis, Fourier-transform infrared and nuclear magnetic resonance spectroscopy all confirmed the successful grafting of GA onto chitosan. The conjugation of GA onto chitosan probably occurred between amine (C-2), hydroxyl groups (C-3 and C-6) of chitosan and carboxyl groups of GA, forming amide and ester linkages, respectively. Differential scanning calorimetry and X-ray diffraction spectra indicated that GA grafted chitosan (GA-g-chitosan) had decreased thermal stability and crystallinity as compared to chitosan. Notably, GA-g-chitosan showed increased α-glucosidase and α-amylase inhibitory activity with the increase of grafting ratio. These results indicated the potential of GA-g-chitosan in the development of an effective anti-diabetic agent.

Preparation, characterization and antioxidant activity of phenolic acids grafted carboxymethyl chitosan.

In this study, three phenolic acids including gallic acid (GA), caffeic acid (CA) and ferulic acid (FA) were grafted onto N,O-carboxymethyl chitosan (NOCC) by a free radical mediated grafting method. The grafted copolymers obtained were all water-soluble samples. UV-vis absorption peaks of the grafted copolymers shifted toward longer wavelengths. FT-IR spectroscopy of the grafted copolymers exhibited additional phenolic characteristics of the aromatic ring CC stretching within 1450-1650 cm(-1). NMR spectroscopy of the grafted copolymers showed new peaks at 6.2-7.6 ppm assigned to the phenyl protons of phenolic acids. These results all confirmed the successful grafting of three phenolic acids to NOCC. The conjugation probably occurred at amine of NOCC and carboxyl groups of phenolic acids. The grafted copolymers exhibited decreased crystallinity as compared to NOCC and chitosan. Moreover, antioxidant activity in vitro assays showed that the antioxidant property decreased in the order of GA-g-NOCC>CA-g-NOCC>FA-g-NOCC>NOCC>chitosan. Our results suggested the potential of phenolic acids grafted NOCC for the development of effective antioxidant agents.

Changes in reactive oxygen species production and antioxidant enzyme activity of Agaricus bisporus harvested at different stages of maturity.

BACKGROUND: The edible mushroom Agaricus bisporus is more prone to senescence than most other vegetables. However, the senescence of A. bisporus before harvesting is often ignored. In this study the changes in reactive oxygen species (ROS) production and antioxidant enzyme activity of A. bisporus harvested at four different stages of maturity were investigated. RESULTS: The firmness of A. bisporus decreased from 6.22 to 5.12 N. Respiration rate increased from 540.65 to 609.82 mg CO2 kg⁻¹ fresh weight (FW) h⁻¹. Browning degree increased from 0.42 to 0.71, showing a positive correlation with polyphenol oxidase activity. For ROS production, superoxide radical production rate increased from 0.51 to 1.16 nmol g⁻¹ FW s⁻¹. Hydrogen peroxide content increased from 0.81 to 1.39 nmol g⁻¹ FW and then decreased rapidly to 0.68 nmol g⁻¹ FW. Malondialdehyde content increased from 1.58 to 2.64 nmol g⁻¹ FW. For antioxidant enzymes, superoxide dismutase and peroxidase activities decreased significantly at stage 4, whereas a significant increase in catalase activity was found at stages 3 and 4. CONCLUSIONS: The balance between ROS and antioxidants was destroyed at stage 4, causing extensive senescence of mushroom tissues. Thus A. bisporus should be harvested at stage 3.

In vitro and in vivo antioxidant activity of ethanolic extract of white button mushroom (Agaricus bisporus).

The antioxidant activities of ethanolic extract from edible mushroom Agaricus bisporus (A. bisporus) were evaluated by various methods in vitro and in vivo. In antioxidant assays in vitro, ethanolic extract of A. bisporus was found to have strong reducing power, superoxide radical, hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, and moderate hydrogen peroxide scavenging activity. In antioxidant assays in vivo, mice were administered with ethanolic extract of A. bisporus via gavage for 30 consecutive days. As a result, administration of ethanolic extract significantly enhanced the activities of antioxidant enzymes in serums, livers and hearts of mice. In addition, the total phenolic content in the extract determined by Folin-Ciocalteu method was 6.18mg of gallic acid equivalents per gram of dry weight. The main phenolic compounds in ethanolic extract analyzed by ultra-high performance liquid chromatography tandem mass spectrometry were determined as gallic acid, protocatechuic acid, catechin, caffeic acid, ferulic acid and myricetin. These results suggested that ethanolic extract of A. bisporus had potent antioxidant activity and could be explored as a novel natural antioxidant.

[Degradation of cell wall polysaccharides during postharvest fruit ripening and softening of different apple varieties].

The cell wall material (CWM) and eight cell wall polysaccharides fractions were extracted from 'Fuji' and 'Kinsei' apples during storage at different time (0 and 42 days). The sugar composition characteristics of each fraction were determined by gas chromatography. The results showed that, during storages, the firmness of 'Kinsei' apples decreased significantly, and a significant peak of ethylene production was shown after 10 d storage, but only a little ethylene was produced in 'Fuji' apples, which had a better storability. Compare to other cell wall polysaccharide fractions, in Na(2)CO(3)-soluble pectic fractions of apple fruit, there were abundant rhamnogalacturonan I (RG-I), which branched highly in side chains due to the compositions of arabinans, galactans, arabinogalactans etc. As for cell wall polysaccharides, in 'Kinsei' apples, the decrease of pectic fractions was shown most significantly in Na(2)CO(3)-1 fraction, which was associated with a significant degradation of arabinosyl and galactosyl residues on the side chains. Further more, higher molecular mass in Na(2)CO(3)-1 pectic polysaccharides degraded and turned into ones with smaller molecular mass. From these results, the degradation of side chains in Na(2)CO(3)-1 pectic polysaccharides under the activity of enzyme was considered one of the most significant factors of apple fruit softening through modifying the network of cell wall polysaccharides.

Changes in cell wall polysaccharide of harvested peach fruit during storage.

Changes in cell wall structure, decrease in tissue firmness and ethylene production in honey peach [Prunus persica (L.) Batsch, cv. 'Yuhuasanhao'] were investigated after various storage at 5 degrees C and at 20 degrees C. The results showed that during storage, the peak of ethylene production lagged significantly behind the rapid softening of peach fruit, which means that it is not ethylene causes the softening of peach fruit. The structural and compositional changes of cell wall of fruits stored at 5 degrees C and at 20 degrees C suggested that low temperature storage inhibited the changes in pectins and cell wall materials (CWM)-residue fraction and delayed the softening of peach fruit. Ruptures of the pectic main chains rich in galacturonic acid occurred. Loss of arabinose and galactose was detected both in pectins and CWM-residue. These results suggested that softening of harvested peach fruit involved the solubilization and degradation of side chains of pectin and CWM-residue fraction, which were probably due to the increased activities of cell wall polysaccharide-related enzymes. However, the loss of neutral sugars in hemicellulosic polysaccharides was not correlated with fruit softening.

[The parents' opinions on screening program regarding newborn hearing].

OBJECTIVE: To investigate opinions on screening of newborn hearing from parent's and its influence to parents and their families. METHODS: Parents were divided into two groups and were given the same questionnaire. Those parents whose babies had passed the first test were in the first group, and those parents whose babies failed the test were in the second group. RESULTS: Most of the parents showed their ignorance to hearing screening with about 97.5% of parents admitted they had little knowledge of hearing screening. 93.06% of the parents showed positive attitude to the screening after being informed of the test. 59.73% of the parents thought the test results were reliable. 73.12% of the parents whose babies showed negative result at the first-test, thought the results were accurate. There were only 38.19% of the parents whose babies failed the first test held the same opinion. We also found that there were some disagreement among 78% of the parents who believed that the positive screening results might cause additional psychological stress on them and therefore affecting their normal family life. CONCLUSIONS: Being informed of the screening, parents showed awareness of the test and were willing to cooperate. They believed the test was beneficial to their babies. Some parents whose babies did not pass the first screening test were often doubtful to the results and refused to be followed up. Therefore, we should improve our diagnostic technology to reduce the negative effects of the test. The results of our investigation suggested that the newborn hearing screening was applicable in our country.

[Hearing screening for high-risk newborns].

OBJECTIVE: To investigate the morbidity of congenital hearing impairment among high-risk newborns and the relevant pathogenic factors. METHODS: Initial screening of hearing by otoacoustic emission (OAE) was conducted among 208 high-risk newborns, 130 males and 78 females after they were born and the second screening was conducted by OAE was conducted 42 days after those with positive results were examined by auditary brainstem response (ABR). RESULTS: All of the 208 newborns received the initial screening with a screening rate of 100%, and 130 newborns received the second screening with a screening rate of 62.5%. The positive rates in the initial screening and second screening were 34.61% and 7.14% respectively. Six newborns were examined by ABR and 2 of them were diagnoses as with hearing impairment with a prevalence rate of 1.78%. The factors, such as sex, age, and Apgar score affected the initial screening results. CONCLUSION: The most proper time for initial hearing screening is around the 42nd day after birth. High-risk newborns should receive regular test even though they pass the initial screening. A special follow-up system should be constructed for the high-risk newborns.