Yuliang Cheng

SiO2@Au nanoshells-based SERS method for detection of sunset yellow and chrysoidine.

A novel surface-enhanced Raman scattering (SERS) substrate made up of SiO2@Au nanoshells has been developed for detecting sunset yellow and chrysoidine. It exhibits an excellent enrichment SERS effect on these two colorant molecules. In this work, density functional theory (DFT) calculations have been carried out to determine the molecular structure and theoretical Raman spectra. This provided a good description of the characteristic peaks of the molecules. In addition, the appropriate thicknesses of the shell and environment pH have been derived to obtain improved SERS signals. The lowest concentration is 1 ppm and 0.5 ppm for sunset yellow and chrysoidine, respectively. Under optimal detection condition, it has proved possible to distinguish each colorant by its characteristic peaks in the SERS spectra of a mixture of the two colorants.

Release of bisphenols from can coatings into canned beer in China market.

BACKGROUND The aim of this research was to understand the migration of bisphenols from can coatings into foods in the Chinese market. RESULTS The migration of bisphenols was studied in commercial cans from the Chinese market filled with four types of food simulant (FS), which were heated at 121 °C for 30 min and stored at 40 °C for 30 days. Only bisphenol A (BPA) and bisphenol A diglycidyl ether (BADGE) were found in the can coatings, and SimC (10% (v/v) ethanol/water) was the most suitable FS for their release. The levels of these bisphenols in 24 kinds of canned beer from Chinese markets were also investigated. The average concentrations of BPA and BADGE were 2.85 ± 0.79 and 0.38 ± 0.19 µg · L⁻¹ respectively, which were both lower than the EU limits, and their respective daily intakes were estimated at 0.015 and 0.0020 µg · kg⁻¹ body weight · day⁻¹. Besides, increasing storage temperature and time accelerated the release of bisphenols into FSs. CONCLUSION The present results provide some guidance to reduce the migration of bisphenols during the transport and storage of canned foods.

Inhibitory effects of cinnamon and clove essential oils on mold growth on baked foods

This study evaluated the minimum inhibition concentration (MIC) and minimum lethal concentration (MLC) of cinnamon and clove essential oils against mold growth on green bean cake and finger citron crisp cake, and also examined the effects of these two essential oils and their application methods on the shelf life of the baked products in normal and vacuum packages by accelerated storage test. The results showed that the MIC of cinnamon and clove essential oils against molds were 0.21-0.83 and 0.21-1.67μL/mL, respectively and the MLC were 0.42-0.83 and 0.83-1.67μL/mL, respectively. In normal package cinnamon and clove essential oils could prolong the shelf life of green bean cake 9-10 and 3-4days, respectively and could prolong the shelf life of finger citron crisp cake 5-6 and 2-3days, respectively. And in vacuum package they were 15-16, 8-9, 10-12 and 7-9days, respectively in turn.

Characterization of lipid oxidation process of beef during repeated freeze-thaw by electron spin resonance technology and Raman spectroscopy

In this study, electron spin resonance (ESR) and Raman spectroscopy were applied to characterize lipid oxidation of beef during repeated freeze-thaw (RFT). Besides the conventional indexes including peroxide values (PV), thiobarbituric acid-reactive substances (TBARS) and acid values (AV) were evaluated, the radical and molecular structure changes were also measured by ESR and Raman spectroscopy. The results showed that PV, TBARS and AV were increased (P<0.05) after RFT. This suggested that lipid oxidation was occurred during RFT. With the increase of radical signal intensity, lower oxidation stability was presented by ESR. Raman intensity of ν(CC) stretching region (1655cm-1) was decreased during RFT. Furthermore, lower Raman intensity ratio of I1655/I1442, I1655/I1745 that determine total unsaturation was also observed. Significant correlations (p<0.01) were obtained among conventional methods, ESR and Raman spectroscopy. Our result has proved that ESR and Raman spectroscopy showed great potential in characterizing lipid oxidation process of beef during RFT.

Anti-cancer effects of torulene, isolated from Sporidiobolus pararoseus, on human prostate cancer LNCaP and PC-3 cells via a mitochondrial signal pathway and the down-regulation of AR expression

In this work, we investigated the anti-cancer effect of torulene, a carotenoid from Sporidiobolus pararoseus, on androgen-sensitive/insensitive prostate cancer cells lines and found that torulene induced apoptosis at moderate cytotoxic concentrations in both cell lines. It was further demonstrated that the apoptosis induced by torulene was due to the modulation of Bcl-2 family members, resulting in decrease of mitochondria membrane potential and increase of the intracellular calcium concentration. Furthermore, its growth-inhibitory effects on LNCaP cells also showed a relationship with the down-regulation of AR and PSA expression. Therefore, the results indicated that a mitochondria-mediated pathway and the expression of AR might play essential roles in the apoptosis process induced by torulene in prostate cancer cells.

Study on the Removal of Cadmium in Rice Using Microbial Fermentation Method

This work mainly examined how to remove cadmium in rice by fermentation, the removal mechanisms, and the quality of fermented rice in order to utilize cadmium-contaminated rice. The fermentation time, temperature, liquid ratio, inoculant levels, and number of washes were varied to optimize the efficiency of cadmium removal. The optimum fermentation process, in which the rate of cadmium removal from the rice is 80.84%, required an inoculant amount of 0.1%, a liquid ratio of 1:1, a period of 60 h at 37 °C, and subsequently washed with water 4 times. The physicochemical properties of raw cadmium-contaminated rice and fermented rice were studied. Results showed that the pasting temperature of the fermented rice became lower, and temperature at which pasting starts dropped but the endothermic enthalpy increased, implying that the protein content in the rice decreased during the fermentation. It suggested that the crystal structure of rice starch changed and fermentation did not result in the formation of new chemical bonds or functional groups in the rice. Microbial fermentation method can therefore effectively reduce cadmium level in contaminated rice.

Torulene and torularhodin, protects human prostate stromal cells from hydrogen peroxide-induced oxidative stress damage through the regulation of Bcl-2/Bax mediated apoptosis

Abstract The current study was designed to elucidate the cytoprotective effects and possible mechanisms of torulene and torularhodin on hydrogen peroxide (H2O2)-induced oxidative stress damage in human prostate stromal cells (WPMY-1). After treated with H2O2, a notable decrease was appeared in cell viability, yet the decrease was attenuated when cells were pretreated with torulene and torularhodin (0.5–10 μM) as evaluated by WST-1 assay. Pretreatment with these two carotenoids significantly attenuated H2O2-induced apoptosis in WPMY-1 cells through the inhibition of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) overproduction, as well as the activation of the activities in catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Finally, pretreatment of cells with carotenoids resulted in the regulation of the mRNA and protein expression of Bcl-2 and Bax in H2O2-exposed prostate stromal cells. The present results indicate that both torulene and torularhodin can protect human prostate stromal cells from oxidative stress damage via Bcl-2/Bax mediated apoptosis.

Hexanal as a QS inhibitor of extracellular enzyme activity of Erwinia carotovora and Pseudomonas fluorescens and its application in vegetables

To prevent the postharvest disease of Chinese cabbage and lettuce, hexanal was used as a control measure to inhibit N-acyl homoserine lactone (AHL) production and extracellular enzymes regulated by quorum-sensing (QS) in their main spoilage strains of Erwinia carotovora and Pseudomonas fluorescens. Firstly, the QS inhibition of hexanal was verified by significantly inhibiting violacein production (p < 0.05) in Chromobacterium violaceum CV026 at sub-MICs. β-Galactosidase activities which reflected AHL production, were significantly inhibited by hexanal, its inhibitory effect was concentration-dependent under minimal inhibitory concentration (MIC) (p < 0.05). The detected extracellular enzymes activities decreased with the increase of hexanal concentration (p < 0.05), including cellulase, xylanase, pectate lyase, polygalacturonase, and protease. Chinese cabbage soft rot and lettuce leaf scorch could be significantly inhibited by hexanal (p < 0.05) without any phytotoxicity effect, the 1/2 MIC of hexanal showed the best inhibitory effect. And all the above effects showed a dose-dependent. A novel preservation technique in reducing the loss of vegetables due to spoilage based on the QS inhibitor was developed.

Application of edible coating with essential oil in food preservation

Abstract Compared with other types of packaging, edible coatings are becoming more and more popular because of their more environmentally friendly properties and active ingredients carrying ability. The edible coating can reduce the influence of essential oils (EOs) on the flavor of the product and also can prolong the action time of EOs through the slow-release effect, which effectively promote the application of EOs in food. Understanding the different combinations of edible coatings and EOs as well as their antimicrobial effects on different microorganisms will be more powerful and targeted to promote the application of EOs in real food systems. The review focus on the contribution of the combination of EOs and edible coatings (EO-edible coatings) to prolong the shelf life of food products, (1) specifically addressing the main materials used in the preparation of EO-edible coatings and the application of EO-edible coatings in the product, (2) systematically summarizing the main production method of EO-edible coatings, (3) discussing the antiseptic activity of EO-edible coatings on different microorganisms in food.

Regeneration of tert -butylhydroquinone by tea polyphenols

To study the antioxidant capacity (AC) regeneration of tert-butylhydroquinone (TBHQ) by tea polyphenols (TPs), a separable system has been designed for its evaluation. The AC values of three natural food matrices (liquorice, oat, and ginger) and TBHQ regenerated by TPs were all higher than their controls, and similar to the initial values (p<0.05). The average regeneration efficiency (RE) value was 1.49 for these three natural food matrices, and 0.82 for TBHQ. Electron paramagnetic resonance spectroscopy analysis has revealed the synergistic effect of TBHQ and TPs, which arose from the regeneration of TBHQ by TPs. The RE value of TBHQ regeneration by TPs embedded in a gelatine membrane was 0.51. The results demonstrated that TPs showed a capacity for regenerating TBHQ, indicating a potential application in regenerative packaging, whereby one antioxidant would be added to the food matrix, with another one as the regenerator incorporated into the packaging material.