Aidong Sun

Studies of the protective effect and antioxidant mechanism of blueberry anthocyanins in a CC14-induced liver injury model in mice

Abstract This study investigated the protective effects and antioxidant mechanisms of blueberry anthocyanin extract (BBAE) in vivo and in vitro using the model of acute CC14-induced liver injury in mice. It was found that BBAE significantly inhibited CC14-induced liver injury and inhibited acute ethanol-induced increases in alanine aminotransferase, aspartate aminotransferase and malondialdehyde in a dose-dependent manner (P<0.05). The activities of superoxide dismutase, catalase and glycogen and glutathione reductase were markedly increased in the anthocyanin group (P<0.01). BBAE also significantly suppressed cellular injury and apoptotic cell death. In summary, BBAE possesses marked protective effects against CC14-induced liver injury, related to its ability to reduce human embryonic-liver cell (L-02) apoptosis and damage induced by oxidative stress. These findings indicate that BBAE may be of value in protecting against acute liver injury, providing pharmacological evidence supporting its clinical application.

Influence of Pulsed Electric Field and Thermal Treatments on the Quality of Blueberry Juice

Fresh blueberries were selected as trial materials. Two blueberry juice samples were sterilized using pulsed electric field and thermal treatments respectively. Their qualities were analyzed and compared by evaluating the microorganisms in the samples. The changes in the quality of fresh blueberry juice samples during storage were also assessed. The results showed that the inactivation of Escherichia coli increased as electric field strength and treatment time increased. Pulsed electric field treatments at 35 kV/cm and 82 μs reduced E. coli by 5.12 logarithms. Pulsed electric field had less effect on juice quality, but after heat treatment, the vitamin C of blueberry juice sample was reduced by 14.78%, whereas its anthocyanin content was reduced by 3.64%. After sterilization, no significant change was observed in the relative reducing sugar, total acid, phenol contents, and Brix value. The vitamin C and anthocyanins contents of the fresh blueberry juice samples treated with pulsed electric field were higher than those treated with heat sterilization.

Assessment of Glucosinolates in Chinese Kale by Near-Infrared Spectroscopy

The contents of individual and total glucosinolate in Chinese kale (Brassica albograbra Bailey) were determined and analyzed using near-infrared spectroscopy. The near infrared calibration mathematics model between total glucosinolate contents and spectral measurement was established based on modified partial least squares. The coefficient of determination of the cross-validation (1-VR), coefficient of determination in prediction and ratio of the standard deviation to the standard error of the cross-validation of the near-infrared spectroscopy calibration equations were 0.92, 0.91, and 3.59 for total glucosinolates; 0.87, 0.82, and 2.78 for gluconapin; 0.93, 0.93, and 3.84 for glucobrassicin; and 0.86, 0.90, and 3.70 for neoglucobrassicin. Near-infrared spectroscopy showed high accuracy in predetermining individual and total glucosinolate contents in Chinese kale.

Stability of Apple Polyphenols as a Function of Temperature and pH

The effect of heat treatment on apple polyphenols was investigated at six different temperatures over three different lengths of time. Apple polyphenols, after heat treatment, maintained similar concentrations in solution compared to the control (at room temperature). The effect of pH on apple polyphenols was investigated at 11 different pH levels and at 2 different temperatures. The pH-optimum for apple polyphenols proved to be 5.0. Two apple polyphenol concentrations, three vitamin C concentrations, two sugar concentrations, and two different temperatures were chosen to investigate the effect of apple polyphenols on vitamin C. Apple polyphenols showed good stability and can be used in many types of food products.

Direct Acylation of Cyanidin-3-Glucoside with Lauric Acid in Blueberry and Its Stability Analysis

Cyanidin-3-glucoside is an anthocyanin that is abundant in blueberry. Lauric acid was used as the acyl donor in the acylation of cyanidin-3-glucoside. Preparative high performance liquid chromatography was used to separate and purify the acylated cyanidin-3-glucoside, the acylated rate was 30.78%. Fourier transform infrared spectroscopy and liquid chromatography mass spectrometry were used to confirm the basic structure of cyanidin-3-glucoside. Lauric acid was combined with cyanidin-3-glucoside. Lauric acid reacted with the glucoside’s primary hydroxyl group and removed a molecule of water, thereby resulting in the obtained structure. The compositions of the unacylated cyanidin-3-glucoside and acylated cyanidin-3-glucoside were compared under different temperatures and under illumination. The effects of different concentrations of additive compounds on the stability of acylated cyanidin-3-glucoside were compared. Stability of acylated cyanidin-3-glucoside was obviously higher than that of the unacylated cyanidin-3-glucoside because of the higher stability of the ester group than the hydroxyl group. The primary hydroxyl esterification of glucoside improved cyanidin-3-glucoside.

Retracted: Properties and stability of blueberry anthocyanin – bovine serum albumin nanoparticles

BACKGROUND Since they would be easily decomposed under alkaline conditions, anthocyanins are likely to have poor oxidation stability. However, encapsulated with protein molecules, anthocyanins could be protected owing to the slowing down of the oxidation process. In this study, the characteristics of nanoparticles, formed by the interactions of anthocyanins with bovine serum albumin (BSA), and their impact on the oxidation stability of anthocyanins were investigated. RESULTS Both BSA and anthocyanin-bound BSA could form self-assembled nanoparticles in phosphate buffer (pH 7.4), and the particle size of anthocyanin-bound BSA (20-25 nm) was smaller than that of BSA (35-40 nm). The ratio of BSA to anthocyanin was 1:10. The radical scavenging rates of BSA-bound anthocyanin were lower than those of the unbound anthocyanin. No significant difference was seen in the stability between the unbound and BSA-bound anthocyanin in the simulated gastric system, whereas a difference was seen in the simulated intestinal system. The amount of unbound anthocyanin decreased by 70% after 6 h, while BSA-bound anthocyanin was almost unchanged. BSA exhibited a remarkable effect on the oxidation stability of anthocyanins. CONCLUSION BSA nanocarriers could improve the stability of anthocyanin under neutral conditions, which has great potential for applications.

Properties and stability of blueberry anthocyanin – bovine serum albumin nanoparticles

BACKGROUND: Since they would be easily decomposed under alkaline conditions, anthocyanins are likely to have poor oxidation stability. However, encapsulated with protein molecules, anthocyanins could be protected owing to the slowing down of the oxidation process. In this study, the characteristics of nanoparticles, formed by the interactions of anthocyanins with bovine serum albumin (BSA), and their impact on the oxidation stability of anthocyanins were investigated. RESULTS: Both BSA and anthocyanin‐bound BSA could form self‐assembled nanoparticles in phosphate buffer (pH 7.4), and the particle size of anthocyanin‐bound BSA (20–25 nm) was smaller than that of BSA (35–40 nm). The ratio of BSA to anthocyanin was 1:10. The radical scavenging rates of BSA‐bound anthocyanin were lower than those of the unbound anthocyanin. No significant difference was seen in the stability between the unbound and BSA‐bound anthocyanin in the simulated gastric system, whereas a difference was seen in the simulated intestinal system. The amount of unbound anthocyanin decreased by 70% after 6 h, while BSA‐bound anthocyanin was almost unchanged. BSA exhibited a remarkable effect on the oxidation stability of anthocyanins. CONCLUSION: BSA nanocarriers could improve the stability of anthocyanin under neutral conditions, which has great potential for applications.

Analysis of Polyphenols in Apple Pomace using Gas Chromatography-Mass Spectrometry with Derivatization

N, O-double (three methyl silane) trifluoro ethyl amide was used to derivatize polyphenols in apple pomace, and the resultant products were tested. The optimal derivatization conditions were then used in conjunction with the rapid analysis of polyphenols by gas chromatography-mass spectrometry. In the results, the following conditions for derivatization with N, O-double (three methyl silane) trifluoro ethyl amide were obtained : Polyphenols should be derivatized for 12 h at 37.5oC with a mass ratio of derivatization reagent to sample being 10 to 1. After analysis through gas chromatography-mass spectrometry, 24 compounds were identified, 11 of which were phenolic compounds and organic acids. Furthermore, four isomeric compounds of epicatechin were separated out. The method proved to be easy to use and sensitive, and could be used to analyze unknown phenolic compounds.

Influence of Pulsed Electric Field on Escherichia coli and Saccharomyces cerevisiae

Heat sterilization destroys the color, smell, taste, and nutrients of food. Pulsed electric field can effectively kill microorganisms for many foods at room temperature without compromising sensory and nutritional quality. The effect of pulsed electric field on the sterilization rates of Escherichia coli and Saccharomyces cerevisiae was investigated. The fundamental mechanism of pulsed electric field sterilization on S. cerevisiae was briefly discussed. The inactivation of E. coli and S. cerevisiae increased as the electric field strength and treatment time increased. Pulsed electric field treatments at 35 kV/cm and 90 μs reduced S. cerevisiae and E. coli by 5.30 and 5.15 log numbers, respectively. The inactivation of E. coli and S. cerevisiae was not remarkable at increased conductivity and the same electric field strength. Concaves and holes in S. cerevisiae cell surface, protoplast deletion, overflow of substances from cells, and denatured DNA were observed. These results supported the hypothesis of “membrane perforation” to explain the mechanism underlying pulsed electric field sterilization.

Protective effects and antioxidant mechanism of bamboo leaf flavonoids on hepatocytes injured by CCl4

The protective effects and antioxidant mechanisms of bamboo leaf flavonoids (BLFs) on hepatocytes injured by CCl4 were studied by establishing models of hepatocyte damage induced by CCl4 and detecting the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutathione peroxidase (GSH-Px), superoxide dismurase (SOD), malondialdehyde (MDA) content and liver glycogen content. The degree of lesions in liver tissues between model and dosage groups was observed through paraffin sections. Results showed that BLFs significantly inhibit CCl4-induced liver injury. The ALT and AST activities as well as MDA contents of cells decreased significantly after treatment with BLFs. GSH-Px and SOD activities as well as liver glycogen contents remarkably increased in the flavonoids groups, which exhibited dose-dependent relationships (P < 0.05). The degree of lesions in liver tissues in the BLF groups was microscopically better than that in the model group. BLFs also significantly suppressed hepatocellular injury and death of apoptotic cells. Therefore, BLFs have remarkable protective effects on acute liver injury, which is related to its strong antioxidant capacity to reduce damage in the liver caused by oxidative stress and cell (NCTC-1469) apoptosis. The results of this study provide pharmacological evidence to support the clinical application of BLFs.