Qi-Jun Wang

Suitability of hyperspectral imaging for rapid evaluation of thiobarbituric acid (TBA) value in grass carp (Ctenopharyngodon idella) fillet.

The suitability of hyperspectral imaging technique (400-1000 nm) was investigated to determine the thiobarbituric acid (TBA) value for monitoring lipid oxidation in fish fillets during cold storage at 4°C for 0, 2, 5, and 8 days. The PLSR calibration model was established with full spectral region between the spectral data extracted from the hyperspectral images and the reference TBA values and showed good performance for predicting TBA value with determination coefficients (R(2)P) of 0.8325 and root-mean-square errors of prediction (RMSEP) of 0.1172 mg MDA/kg flesh. Two simplified PLSR and MLR models were built and compared using the selected ten most important wavelengths. The optimised MLR model yielded satisfactory results with R(2)P of 0.8395 and RMSEP of 0.1147 mg MDA/kg flesh, which was used to visualise the TBA values distribution in fish fillets. The whole results confirmed that using hyperspectral imaging technique as a rapid and non-destructive tool is suitable for the determination of TBA values for monitoring lipid oxidation and evaluation of fish freshness.

Enzymatic preparation of 20(S, R)-protopanaxadiol by transformation of 20(S, R)-Rg3 from black ginseng

20(S)-protopanaxadiol (PPD(S)) and 20(R)-protopanaxadiol (PPD(R)), the main metabolites of ginsenosides Rg3(S) and Rg3(R) in black ginseng, are potential candidates for anti-cancer therapy due to their pharmacological activities such as anti-tumor properties. In the present study, we report the preparation of PPD(S, R) by a combination of steaming and biotransformation treatments from ginseng. Aspergillus niger was isolated from soil and showed a strong ability to transform Rg3(S, R) into PPD(S, R) with 100% conversion. Furthermore, the enzymatic reactions were analyzed by reversed-phase HPLC, showing the biotransformation pathways: Rg3(S)-->Rh2(S)-->PPD(S) and Rg3(R)-->Rh2(R)-->PPD(R), respectively. In addition, 12 ginsenosides including 3 pairs of epimers, namely Rg3(S), Rg3(R), Rh2(S), Rh2(R), PPD(S) and PPD(R), were simultaneously determined by reversed-phase HPLC. Our study may be highly applicable for the preparation of PPD(S) and PPD(R) for medicinal purposes and also for commercial use.

Enhanced lovastatin production by solid state fermentation ofMonascus ruber

The purpose of this study was to optimize the solid state cultivation ofMonascus ruber on sterile rice. A single-level-multiple-factor and a single-factor-multiple-level experimental design were employed to determine the optimal medium constituents and to optimize carbon and nitrogen source concentrations for lovastatin production. Simultaneous quantitative analyses of the β-hydroxyacid form and β-hydroxylactone for of lovastatin were performed by the high performance liquid chromatography (HPLC) method with a UV photodiode-array (PDA) detector. The total lovastatin yield (4≈6 mg/g, average of five repeats) was achieved by adding soybean powder, glycerol, sodium nitrate, and acetic acid at optimal composition of the medium increased by almost 2 times the yield observed prior to optimization. The experimental results also indicated that the β-hydroxylactone form of lovastatin (LFL) and the β-hydroxyacid form of lovastatin (AFL) simultaneously existed in solid state cultures ofMonascus ruber, while the latter was the dominant form in the middle-late stage of continued fermentation. These results indicate that optimized culture conditions can be used for industrial production of lovastatin to obtain high yields.

Vacuum Cooling of Meat Products: Current State-of-the-Art Research Advances

Vacuum cooling (VC) is commonly applied for cooling of several foodstuffs, to provide exceptionally rapid cooling rates with low energy consumption and resulting in high-quality food products. However, for products such as meat and cooked meat products, the higher cooling loss of vacuum cooling compared with established methods still means lower yields, and important meat quality parameters can be negatively affected. Substantial efforts during the past ten years have aimed to improve the technology in order to offer the meat industry, especially the cooked meat industry, optimized production in terms of safety regulations and guidelines, as well as meat quality. This review presents and discusses recent VC developments directed to the cooked meat industry. The principles of VC, and the basis for improvements of this technology, are firstly discussed; future prospects for research and development in this area are later explored, particularly in relation to cooling of cooked meat and meat products.

TAXOL PRODUCTION BY FUSARIUM ARTHROSPORIOIDES ISOLATED FROM YEW, TAXUS CUSPIDATA

Taxol Production by Fusarium Arthrosporioides Isolated from Yew, Taxus Cuspidata A taxol-producing endophyte was Fusarium arthrosporioides. As a novel taxol resource, a taxol-producing endophyte was successfully isolated from the yew tree, Taxus cuspidata Sieb. et Zucc. According to the morphological characterization and the ITS4-ITS5 sequences, the isolated endophytic fungus was identified as Fusarium arthrosporioides. Fermentation conditions for taxol production were optimized with the isolated strain (F-40) of F. arthrosporioides. The fungal taxol was analytically confirmed by TLC, RP-HPLC, LC-MS and NMR. F. arthrosporioides isolated from yew was found to produce taxol with a maximum yield of 131 μg/L. Precise methods were established for detecting the fungal taxol and its derivatives. Korišćena endofita koja proizvodi taksol bila je Fusarium arthrosporioides. Kao novi izvor taksola, ta endofita koja proizvodi taksol uspešno je izolovana iz stabla tise, Taxus cuspidata Sieb. et Zucc. Prema morfološkoj karakterizaciji i sekvencama ITS4-ITS5, izolovana endofitna gljiva identifikovana je kao Fusarium arthrosporioides. Uslovi fermentacije za proizvodnju taksola poboljšani su pomoću izolovanog niza (F-40) F. arthrosporioides. Taksol dobijen iz gljive analitički je potvrđen pomoću TLC, RP-HPLC, LC-MS i NMR. Utvrđeno je da F. arthrosporioides izolovana iz tise proizvodi taksol u količini od maksimalno 131 μg/L. Ustanovljene su precizne metode za otkrivanje taksola i njegovih derivativa u gljivama.

Effect of Pulsed Electric Field on Microstructure of Some Amino Acid Group of Soy Protein Isolates

Abstract The effect of a pulsed electric field (PEF) on the microstructure of some amino acids was studied. Raman spectrum was used to determine the effect of PEF on tyrosine, tryptophan, proline residues, histidine, arginine, aliphatic amino acid, disulfide bond, and polypeptide backbone in soy protein isolates (SPI). Results suggested that increasing the intensity of PEF gradually to 50 kV cm−1 led to a reduction in gauche C–S conformation of CCSSCC dihedral angles. The increase of the PEF intensity caused an increase in the gauche–gauche–gauche conformation of the disulfide bond accompanying a decrease in α-helix and β-sheet and an increase in antiparallel β-sheet and disorder structure. A critical pulse intensity of 30 kV cm−1 was observed for unfolding and reassembling of SPI, which was verified in our previous study (Liu et al., Eur Food Res Technol 233:841–50). When the pulse intensity gradually increased to around 30 kV cm−1, the exposure of tyrosine and tryptophan, the vibration of CH2 wagging in proline and CH2 in the midazole ring of histidine, the vibration of C—H bending and C—N stretching inside a charged arginine, and asymmetric H—C—H bending deformation vibration in CH2 and CH3 groups in aromatic and aliphatic amino acids gradually increased, suggesting an unfolding of protein molecules. When the pulse intensity continually increased from 30 to 50 kV cm−1, the microstructure of all above amino acids decreased due to the reassembly of unfolding proteins.

Telomerase Inhibitory Effects of Red Pigment Rubropunctatin and Statin Monacolin L Isolated from Red Yeast Rice.

In addition to the cholesterol-lowering activity of red yeast rice (RYR), its anticancer activities have been frequently reported. However, the mechanism of action of the anticancer activity of RYR is not yet fully understood. The objective of the current study was to elucidate anticancer compositions and anticancer mechanism of actions of RYR. The isolated compounds from RYR were subjected to anti-proliferation assay, apoptosis assay via flow cytometry, and telomerase inhibitory assay via telomeric repeat amplification protocol-PCR (TRAP-PCR) assay, and Western blotting assay in an in vitro cell culture system. The results showed that a statin, monacolin L, and a red pigment, rubropunctatin, from RYR exhibited very strong cancer cell proliferation inhibitory effects; the rubropunctatin was comparable with anticancer drug cis-platinum, taxol, and 10-hydroxy-camptothecin (HCPT) in their IC50 values. Monacolin L and rubropunctatin exerted their anticancer activity via telomerase inhibitory effects. Monacolin L and rubropunctatin presented the similar telomerase inhibitory effects as the anticancer drug cis-platinum, while the anticancer drug HCPT presented a weak telomerase inhibitory effect in the TRAP-PCR assay. Meanwhile, rubropunctatin and cis-platinum did not present strong apoptosis induction activity as the momacolin L and HCPT did. These results indicate that the RYR may exert anticancer effects through the telomerase inhibitory effect of rubropunctatin and the apoptosis-induction effect of monacolin L.

Improving the quality and safety of frozen muscle foods by emerging freezing technologies: A review

ABSTRACT Freezing is one of the most widespread used preservation methods for meats including fish meat. Traditional freezing methods such as air blast freezing and cryogenic freezing could induce some quality deterioration such as damage to cell structure, increased drip loss, and poor sensory value. Therefore, novel freezing methods have been developed to minimize the disadvantages of traditional freezing methods. This review describes the enhancement of quality attributes of muscle tissues frozen by novel freezing technologies, including high pressure freezing, electrically and magnetically assisted freezing, ultrasound assisted freezing and antifreeze protein. These quality attributes include microstructure, moisture loss, color, tenderness, protein denaturation, lipid and protein oxidation, and microbial counts. In this review, the principles of these emerging freezing technologies are introduced, and the impacts of these technologies on controlling the formation and growth of ice crystals and on complex changes of protein are also discussed. The current review shows that the novel freezing methods have positive effects on promoting the quality of frozen muscle. At a micro level, the majority of the novel methods have some certain ability on controlling the formation and growth of ice crystals, thus creating smaller, and more homogeneous and regular distribution of ice crystals, leading to better microstructure and enhanced quality attributes of frozen meats. Meanwhile, complex changes of protein take place under some of these novel freezing processes, and therefore the possible negative effect of the changes of protein should also be considered for commercial applications of these technologies in the frozen food industry.

Enhancing Food Processing by Pulsed and High Voltage Electric Fields: Principles and Applications

ABSTRACT Improvements in living standards result in a growing demand for food with high quality attributes including freshness, nutrition and safety. However, current industrial processing methods rely on traditional thermal and chemical methods, such as sterilization and solvent extraction, which could induce negative effects on food quality and safety. The electric fields (EFs) involving pulsed electric fields (PEFs) and high voltage electric fields (HVEFs) have been studied and developed for assisting and enhancing various food processes. In this review, the principles and applications of pulsed and high voltage electric fields are described in details for a range of food processes, including microbial inactivation, component extraction, and winemaking, thawing and drying, freezing and enzymatic inactivation. Moreover, the advantages and limitations of electric field related technologies are discussed to foresee future developments in the food industry. This review demonstrates that electric field technology has a great potential to enhance food processing by supplementing or replacing the conventional methods employed in different food manufacturing processes. Successful industrial applications of electric field treatments have been achieved in some areas such as microbial inactivation and extraction. However, investigations of HVEFs are still in an early stage and translating the technology into industrial applications need further research efforts.