Antioxidant and ammonia-sensitive films based on starch, κ-carrageenan and Oxalis triangularis extract as visual indicator of beef meat spoilage.

In this study, we first investigated the rheological property of sweet potato starch (SPS), κ-carrageenan (KC) and Oxalis triangularis extract (OTE) blends and found that the blends exhibited high apparent viscosity with an apparent shear thinning behavior. And then films based on SPS, KC and OTE were developed and their structural and functional properties were studied. The physico-chemical test results showed that OTE exhibited different colors in solutions with different pH values and the incorporation with OTE and KC could significantly increase the thickness, water vapor permeability, light barrier ability, tensile strength and elongation at break as well as the pH- and ammonia-sensitive properties of the SPS film. The structural property test results showed that some intermolecular interactions between OTE and SPS/KC occurred in SPS-KC-OTE films. Finally, the functional properties of SPS-KC-OTE films were examined and SPS-KC-OTE films showed significant DPPH radical scavenging activity as well as a visible color change in response to changes in beef meat freshness. Our results suggested that the SPS-KC-OTE films could be used as an active and intelligent food packaging material in food industry.

Preparation and characterization of antioxidant and pH-sensitive films based on arrowhead (Sagittaria sagittifolia) starch, κ-carrageenan and black chokeberry (Aronia melanocarpa) extract for monitoring spoilage of chicken wings.

In this study, we firstly developed an antioxidant and pH-sensitive film based on arrowhead starch (AS), κ-carrageenan (KC) and black chokeberry extract (BCE) and its physical and structural properties were investigated. We found BCE showed different colors in different pH solutions and incorporation with KC and BCE could significantly decrease light transmittance, increase thickness, elongation at break and pH-sensitive property of AS film. The results of structural property assay indicated that there were some intermolecular interactions between BCE and AS/KC in AS-KC-BCE films. Secondly, we investigated the rheological property of AS, AS-KC and AS-KC-BCE suspensions and found the suspensions showed an obvious shear-thinning behavior with high apparent viscosity. Finally, the functional properties of AS-KC-BCE films were investigated and AS-KC-BCE films showed strong scavenging activity on DPPH free radical and presented visible colour changes in response to the changes of the chicken wing qualities. The results suggest that AS-KC-BCE films can be used in active and intelligent packaging of food industry.

Optimization for ultrasound-assisted extraction of polysaccharides with antioxidant activity in vitro from the aerial root of Ficus microcarpa.

In this study, optimization of ultrasound-assisted extraction and antioxidant activity of polysaccharides from the aerial root of Ficus microcarpa (FMPS) were investigated. The optimal conditions for extraction of FMPS were determined as followings: ultrasound power 200 W, ultrasound temperature 70°C, extraction temperature 74°C, liquid-solid ratio 35, extraction time 238 min, ultrasound time 49 min. The experimental yield of FMPS (3.44%) obtained under these conditions was well agreement with the value predicted by the model. In addition, Fourier transform-infrared spectroscopy and antioxidant activity assays revealed that FMPS were acidic polysaccharides and had strong Fe2+ chelating activity and moderate hydrogen peroxide scavenging effect. Further work on the purification, structure characterization and antioxidant activity in vivo of FMPS is in progress.

Preliminary separation and purification of resveratrol from extract of peanut (Arachis hypogaea) sprouts by macroporous adsorption resins.

In the present study, the separation and purification characteristics of resveratrol from extract of peanut sprouts (PSE) on 11 macroporous adsorption resins were investigated. The results showed that ADS-5 offered better adsorption and desorption capacity for resveratrol than other tested resins. From the static experiments with ADS-5 resin, we found that the experimental data fitted best to the pseudo-second-order kinetics model and Langmuir isotherm model, and the adsorption was a spontaneous and endothermic process. The separation and purification parameters of resveratrol from PSE were optimised by dynamic adsorption/desorption experiments with the column packed with ADS-5 resin. Under the optimal conditions, after one run treatment with ADS-5 resin, the content of resveratrol in the product was increased 17.9-fold from 1.32% to 23.60%, with a recovery yield of 88.33%. The results demonstrated that ADS-5 resin was a promising basis for large-scale preliminary separation and purification of resveratrol from PSE.

Preliminary characterization and immunostimulatory activity of polysaccharides from Glossaulax didyma.

In the present study, we investigated the preliminary characterization, both in vitro and in vivo immunostimulatory activity of polysaccharides from Glossaulax didyma (GPS). The results of chemical and gas chromatography analysis indicated that GPS was mainly composed of glucose with high contents of uronic acid and sulfate. For immunostimulatory activity in vitro, GPS could stimulate the proliferation of splenocytes and enhance neutral red phagocytosis, TNF-α production level and acid phosphatase activity in mouse peritoneal macrophages. For immunostimulatory activity in vivo, the administration of GPS could significantly increase the level of serum hemolysin in cyclophosphamide-treated mice. The results provided evidences that GPS possessed significant immunostimulatory activity and might be one of important active substances responsible for the immunostimulatory effect of G. didyma.

Preliminary characterization and potential hepatoprotective effect of polysaccharides from Cipangopaludina chinensis.

In the present study, we investigated the preliminary characterization, in vitro antioxidant and in vivo heptoprotective activities of polysaccharides from Cipangopaludina chinensis (CCPS). The results of chemical and gas chromatography analysis indicated that CCPS was mostly composed of glucose with high contents of uronic acid and sulfate. For antioxidant activities in vitro, CCPS showed medium lipid peroxidation inhibition effect and high Fe²âº chelating and hydroxyl radical scavenging activities. For hepatoprotective activity in vivo, the administration of CCPS significantly decreased the serum levels of alanine aminotransferase and aspartate aminotransferase, inhibited the formation of malondialdehyde in liver and tumor necrosis factor-alpha (TNF-α) in serum and restored the liver activities of superoxide dismutase, glutathione peroxidase in BCG/LPS-induced immunological liver injury mice. The results suggested that CCPS had a significant protective effect against BCG/LPS-induced immunological liver injury. The hepatoprotective effect of CSPS might be partly due to its immunoregulatory effect by inhibiting TNF-α production and antioxidant activities to protect biological systems against the oxidative stress, which were dependent on the chemical and structural properties of CCPS. Further work on the structure of CCPS is in progress.

Extraction, characterization and biological activities of polysaccharides from Amomum villosum.

In the present study, the extraction, purification, characterization and biological activities of polysaccharides from the seeds of Amomum villosum (ASP) were investigated. Firstly, the optimal parameters for the extraction of ASP were obtained by using a Box-Behnken Design as follows: extraction temperature 78.8 °C, extraction time 71.3 min and ratio of water to raw material 39.3 ml/g. Then, the crude ASP was sequentially purified by chromatography of DEAE-52 and Sephadex G-100, resulting in three purified fractions of ASP-1, ASP-2 and ASP-3. The results showed that ASP-3 had a larger molecular weight and higher contents of protein, sulfuric radical and uronic acid than the other polysaccharide fractions. Furthermore, ASP-3 showed relative stronger inhibitory activity on the growth of HepG2 cells. Finally, ASP had strong free radical scavenging activities in vitro and significantly prevented the formation of malondialdehyde and enhanced the activities of antioxidant enzymes in CCl4-induced liver injury mice.

Preparation, preliminary characterization and immunostimulatory activity of polysaccharide fractions from the peduncles of Hovenia dulcis.

The peduncles of Hovenia dulcis, containing abundant nutrients and having a taste like a combination of raisin, clove, cinnamon and sugar, have been consumed as fruits and used as traditional herbal medicine for a long time in China. Up to date, little information is available about the polysaccharides from peduncles of H. dulcis (HDPS) and their potential bioactivity. In this study, three purified fractions were prepared by sequential purification of crude HDPS through ion-exchange chromatography and gel-filtration chromatography. The three fractions of HDPS-1, HDPS-2 and HDPS-3 were found to be homogeneous heteropolysaccharides mainly composed of rhamnose, arabinose, galactose and galacturonic acid with an average molecular weight of 235, 70 and 53 kDa, respectively. HDPS-3 was quite different from HDPS-1 and HDPS-2, as it contained much higher content of galacturonic acid (40.5%). In vitro immunostimulatory activity evaluation revealed that all the three fractions could significantly stimulate the proliferation of splenocytes and enhance phagocytosis, nitric oxide production and acid phosphatase activity of peritoneal macrophages, which suggested that HDPS had a potent immunostimulatory activity and could be explored as a potential natural immunomodulatory agent.

The prevalence of Keshan disease in China.

BACKGROUND: Sentinel surveillance of Keshan disease (KD) is limited by unable to give the prevalence rates and their estimates. This study was to find the national KD prevalence and the estimated patient numbers to provide evidence toward modifying the policy of KD prevention and control. METHOD: Using a probability proportional to population size, randomized, multistage, and cluster sampling, we surveyed 101,127, measured grain selenium levels; and surveyed household income with pre-designed questionnaires. RESULTS: The national prevalence rates of KD, chronic KD and latent KD were 2.21%, 0.50%, and 1.71% respectively. Chronic KD patients are mainly in the provinces where KD had been seriously epidemic. The KD prevalence rate was higher in females (2.20%) than in males (1.98%). These were also higher in older age groups. The cases younger than 30 years accounted for 13.6%, indicating the possibility that KD is still occurring. Nationally, the estimated numbers of KD and chronic KD patients are 1,675,500 (95% CI, 1,608,500-1,747,300) and 379,800 (95% CI, 346,700-412,800) respectively. Multiple logistic regression analysis indicated that family income was a significant dependent variable (OR: -0.258, 95% CI: -0.332 to -0.185, p<0.001). More than 2000 chronic KD patients found in the study were treated in 2009-2011. The limitation of this study was that sampling size was determined at national level. CONCLUSION: KD is still a public health issue among the people of the historically severe endemic areas. Selenium supplementation, self-management program for chronic KD patients and translation epidemiology of KD surveillance should be strengthened.

Preliminary characterization, antioxidant activity in vitro and hepatoprotective effect on acute alcohol-induced liver injury in mice of polysaccharides from the peduncles of Hovenia dulcis.

The fresh fleshy peduncles of Hovenia dulcis have been used as a food supplement and traditional herbal medicine for the treatment of liver diseases and alcoholic poisoning for more than a millennium. The objectives of the present study, therefore, were to determine the antioxidant activity of polysaccharides from the peduncles of H. dulcis (HDPS) and to evaluate its hepatoprotective effect on acute alcohol-induced liver injury in mice. HDPS, prepared by hot water extraction, ethanol precipitation and treatment of macroporous resin, was found to be non-starch polysaccharide and mainly composed of galactose, arabinose, rhamnose and galacturonic acid. In in vitro antioxidant assay, HDPS exhibited high superoxide radical scavenging activity, strong inhibition effect on lipid peroxidation and a medium ferrous ion-chelating activity. For hepatoprotective activity in vivo, the administration of HDPS significantly decreased the serum levels of alanine aminotransferase and aspartate aminotransferase, significantly decreased the liver level of malondialdehyde and remarkably restored the liver activities of superoxide dismutase and glutathione peroxidase in alcohol-induced liver injury mice. The results suggested that HDPS had a significant protective effect against acute alcohol-induced liver injury possibly via its antioxidant activity to protect biological systems against the oxidative stress.