Co-reporter:Tiantian Wu, Chunhua Wu, Shalu Fu, Liping Wang, Chunhong Yuan, Shiguo Chen, Yaqin Hu
Carbohydrate Polymers 2017 Volume 155() pp:192-200
Publication Date(Web):2 January 2017
DOI:10.1016/j.carbpol.2016.08.076
Lysozyme was integrated into CS-NPs via ionotropic gelation technology by the interaction between NH and OH groups.CS-Lys-NPs showed enhanced antibacterial activity.The antibacterial action was probably due to the ability of nanoparticles to penetrate the cell membrane or influence metabolism enzyme activities and interfere with bacterial metabolism.Lysozyme was integrated into chitosan nanoparticles (CS-NPs) to improve the antibacterial activity. CS-NPs and chitosan-lysozyme nanoparticles (CS-Lys-NPs) were prepared according to the ionic gelation technique and then characterized by average size, zeta potential, polydispersity index (PDI), atomic force microscopy (AFM), fourier transform infrared (FT-IR), small-angle X-ray scattering (SAXS), circular dichroism (CD) and UV⿿visible spectroscopy. Antibacterial properties were investigated by transmission electron microscopy (TEM) based on observation of the inhibition zone and measurement of the minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) of CS-NPs and CS-Lys-NPs against E. coli and B. subtilis. The CS-NPs had particle sizes of 476.2⿿548.1 nm, while an increase to ⿼488.8 to 613.5 nm was observed upon loading with lysozyme. The results suggested that the integration of lysozyme into CS-NPs enhanced the antibacterial activity against E. coli and B. subtilis, which may show great potential for use in the food industry and other applications in the form of direct addition or incorporation into packaging.
Co-reporter:Chunhua Wu, Jinhu Tian, Shan Li, Tiantian Wu, Yaqin Hu, Shiguo Chen, Tatsuya Sugawara, Xingqian Ye
Carbohydrate Polymers 2016 Volume 146() pp:10-19
Publication Date(Web):1 August 2016
DOI:10.1016/j.carbpol.2016.03.027
•The grafting reaction was accompanied with a degradation of the CS molecule.•The CG film-forming solution grafted at a lower GA value behaved like an network system with a more elastic behavior.•The increasing of GA grafting onto the CS chain led to a reduction of TS, E and WVP in the corresponding films.•The antioxidant and antimicrobial activities of CG film increased with DS.•The microstructure of the film was closely related to the observed film properties.The chitosan gallates (CG) were obtained by free-radical-initiated grafting of gallic acid (GA) onto chitosan (CS) in this work. The chemical structures of the CG were corroborated by UV–vis, GPC and 1H NMR analysis. The grafting reaction was accompanied with a degradation of the CS molecule. The shear-thinning flow behavior of CG film-forming solutions (CG FFS) decreased with the grafting amount of GA into CS chain, while the CG FFS grafted at a lower GA value behaved like a networks containing entangled or cross-linked polymer chains with a more elastic behavior. The increasing of GA grafting onto the CS chain led to a reduction of tensile strength, elongation at break and water resistance in the corresponding films, but increases in the antioxidant and antimicrobial activities were observed. The microstructure of the film was investigated using scanning electron and atomic force microscope, and the results were closely related to the observed film properties.
Co-reporter:Chunhua Wu, Liping Wang, Yaqin Hu, Shiguo Chen, Donghong Liu and Xingqian Ye
RSC Advances 2016 vol. 6(Issue 25) pp:20892-20900
Publication Date(Web):10 Feb 2016
DOI:10.1039/C6RA00757K
To improve the availability of citrus essential oil (CEOs), nanoemulsions based on chitosan nanoparticles loaded with CEOs were prepared by the emulsion-ionic gelation technique. The structural information and the coating characteristics of the nanoemulsion as well as its preservation properties on silvery pomfret were investigated. The results showed that the amount of CEOs added into a nanoemulsion reduced the stability and rheological properties of the nanoemulsion systems, which indirectly affected the physicochemical properties of the coatings. The formation of the nanoemulsion was attributed to interactions between the functional groups of chitosan and CEOs by hydrogen bonds and electrostatic interactions. Furthermore, the preservation effects on silvery pomfret by the nanoemulsion coating were better than conventional emulsion coatings, which were ascribed to more efficient preventative microorganisms and lipid oxidation from silvery pomfret by the nanoemulsion coating. These results suggested that nanoemulsion coating containing CEOs have great potential in the seafood preservation field.
Co-reporter:Tiantian Wu, Chunhua Wu, Yingchun Xiang, Jiaqi Huang, Lanlan Luan, Shiguo Chen and Yaqin Hu
RSC Advances 2016 vol. 6(Issue 80) pp:76280-76287
Publication Date(Web):12 Aug 2016
DOI:10.1039/C6RA11197A
This study demonstrated the combined use of sonolysis with the H2O2/ascorbic acid (Vc) redox reaction to degrade chitosan (CS). The influence of operating parameters, such as the initial CS concentration (1–15 mg mL−1), the input power level (15–45% of the total input power), the H2O2 and Vc concentration (10–70 mM) and the pH (3.0–5.0) of the reaction solution, on the molecular weight and degradation kinetics of CS were investigated and optimized. Based on the degradation kinetics, a synergetic effect of sonolysis with H2O2 and Vc on the degradation of CS was observed. Structural analysis by FT-IR and 1H and 13C NMR indicated no significant difference between the chemical structure of chitosan before and after degradation. Moreover, intermolecular hydrogen bonds were broken, and the crystallinity of degraded chitosan decreased. Using the above analysis, CS degradation by the combination of sonolysis with the H2O2/Vc redox reaction was proposed to be due to mechanical effects along with HO˙ attack on the β-1,4-glucoside linkages of glucosamine units. These results suggest that the sonolysis/H2O2/Vc combined technique is promisingly suitable for large-scale manufacture of chitooligosaccharide.
Co-reporter:Chunhua Wu, Tiantian Wu, Zhongxiang Fang, Jiawen Zheng, Shao Xu, Shiguo Chen, Yaqin Hu and Xingqian Ye
RSC Advances 2016 vol. 6(Issue 52) pp:46686-46695
Publication Date(Web):12 May 2016
DOI:10.1039/C6RA06003J
Nisin is an antibiotic peptide widely used in food and pharmaceutical industry. To improve its efficiency, nisin was encapsulated in a poly-γ-glutamic acid (γ-PGA) and chitosan nanoparticle system using self-assembly method. The effects of the nisin concentration and chitosan coating on the properties of the nanoparticles were investigated. The release behavior and transport mechanism of nisin from the nanoparticles were also examined under different conditions (temperature of 4 and 25 °C and pH of 3.0, 6.0 and 8.0 respectively). Results showed that the loading content (LC) and mean particle size of the nanoparticles were increased with the increasing of nisin concentration, but encapsulation efficiency (EE) was declined. The chitosan coating enhanced the stability of nanoparticle (higher ζ potential) and led to a higher EE and LC, and bigger mean particle size. FT-IR spectroscopy suggested that the formation of nisin/γ-PGA/chitosan nanoparticle (N–P–C-NPs) was mainly attributed to the interactions among the function groups of chitosan, γ-PGA and nisin by hydrogen bonding and electrostatic interactions. The release of nisin from the nanoparticles exhibited a pH-dependent pattern, and the experimental data were fitted to a linear superimposition model which suggested that the release mechanism of nisin from the nanoparticles was an anomalous behavior. In addition, the in vitro antibacterial test showed that N–P–C-NPs was more efficient than nisin/γ-PGA nanoparticle or nisin in inhibiting the growth of Escherichia coli O157:H7 and Listeria monocytogenes, suggesting N–P–C-NPs could be developed as a promising novel food preservative.
Co-reporter:Chunhua Wu;Yuan Li;Liping Wang;Jianchu Chen
Food and Bioprocess Technology 2016 Volume 9( Issue 4) pp:675-685
Publication Date(Web):2016 April
DOI:10.1007/s11947-015-1659-9
The synergistic effect of gallic acid (GA) and chitosan (CS) as edible coatings on the quality and shelf life of Pacific mackerel (Pneumatophorus japonicus) fillets during chilled storage was investigated in this study. Pacific mackerel fillets were periodically evaluated to assess their microbiological (total viable count), physicochemical (pH, total volatile basic nitrogen, biogenic amine, thiobarbituric acid, and K value), and sensory characteristics. The results indicated that CS + GA was more effective than either treatment alone in inhibiting microbial growth, protein decomposition, biogenic amine formation, lipid oxidation and nucleotide breakdown, and maintaining better sensory characteristics during storage, thereby extending the shelf life of mackerel by 6 days compared with the control group. Therefore, a coating with the combination of chitosan with GA represents a promising method for maintaining the storage quality of Pacific mackerel fillets and has broad potential applications in the seafood industry as a food-grade biopreservative.
Co-reporter:Chunhua Wu;Shalu Fu;Yingchun Xiang;Chunhong Yuan
Food and Bioprocess Technology 2016 Volume 9( Issue 11) pp:1835-1843
Publication Date(Web):2016 November
DOI:10.1007/s11947-016-1771-5
The effect of chitosan (CS)-gallic acid (GA) conjugate (chitosan gallate, CS-g-GA) coating on the quality of silvery pomfret (Pampus argenteus) during refrigerated storage at 4 °C for 15 days was investigated. The total mesophilic and psychrotrophic microbes in control and coated fish samples were counted periodically; physicochemical analyses to determine pH, total volatile basic nitrogen (TVB-N), peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), K-value, and water-holding capacity (WHC) were carried out; and sensory attributes were evaluated. The results indicated that both CS + GA and CS-g-GA coatings effectively preserved the silvery pomfret quality during refrigerated storage. However, CS-g-GA had higher antimicrobial activity and a better ability to inhibit the formation of volatile bases (TVB-N) and lipid oxidation products (POV and TBARS) as well as the degradation of ATP and its breakdown products (K value) than CS + GA during the storage period. Furthermore, the CS-g-GA coating also helped to maintain a higher WHC and had better sensory properties for a longer period of time compared to the other treated samples, thus extending the shelf life and delaying the deterioration of fresh silvery pomfret by 3–6 days during refrigerated storage. These results suggest that a CS-g-GA coating could be employed as an active packaging material in the fish preservation industry.
Co-reporter:JINJIE ZHANG;DAN WU;DONGHONG LIU;ZHONGXIANG FANG;JIANCHU CHEN;XINGQIAN YE
Journal of Food Biochemistry 2013 Volume 37( Issue 2) pp:212-219
Publication Date(Web):
DOI:10.1111/j.1745-4514.2011.00626.x
ABSTRACT
The effects of six cooking styles, including boiling, steaming, microwaving, grilling, pan-frying and deep-frying, on the lipid oxidation and fatty acid composition of grass carp (Ctenopharyngodon idellus) fillets were investigated. All treatments reduced the moisture contents and increased the relative ratio of protein. Compared with raw samples, the proportions of polar lipid fractions of all samples were increased, while free amino acid contents were significantly decreased. Peroxide values decreased during pan-frying and deep-frying, but remained constant in the samples subjected to the other four cooking methods. Microwave baking and grilling increased the p-anisidine values and resulted in higher lipid oxidative extents. Boiling, steaming, microwave baking and grilling did not affect the fatty acid composition. Pan-frying and deep-frying increased the general polyunsaturated fatty acid content and decreased the n–3/n–6 ratio, especially for the deep-frying cooking method.
PRACTICAL APPLICATIONS
Fish consumption has been linked to health benefits such as reduced risk of coronary heart disease. This is largely attributed to the lipid, cholesterol, fatty acid composition and the polyunsaturated fatty acids present in fish oils. The ω–3 : ω–6 and polyunsaturated fatty acid/saturated fatty acid ratios are considered to be useful criteria for comparing relative nutritional and oxidation values of fish oils. This study was therefore conducted to determine the influence of different cooking styles on the lipid oxidation of grass carp. These features and information are very important to the food health industry because they could be potential guidelines for the clinical, community, foodservice and research dieticians to recommend the proper cooking methods to get better health effects. It is also useful for academic studies on food composition and nutrition.
Co-reporter:Jinjie Zhang;Yanjia Yao;Xingqian Ye
Journal of Food Science and Technology 2013 Volume 50( Issue 3) pp:542-548
Publication Date(Web):2013 June
DOI:10.1007/s13197-011-0376-2
Cooking methods have a significant impact on flavour compounds in fish soup. The effects of cooking temperatures (55, 65, 75, 85, 95, and 100 °C) on sensory properties and protein hydrolysates were studied in crucian carp (Carassius auratus) soup. The results showed that the soup prepared at 85 °C had the best sensory quality in color, flavour, amour, and soup pattern. Cooking temperature had significant influence on the hydrolysis of proteins in the soup showed by SDS-PAGE result. The contents of water soluble nitrogen (WSN) and non-protein nitrogen (NPN) increased with the cooking temperature, but the highest contents of total peptides and total free amino acids (FAA) were obtained at the cooking temperature of 85 °C. The highest contents of umami-taste active amino acid and branched-chain amino acids were also observed in the 85 °C sample. In conclusion, a cooking temperature of 85 °C was preferred for more excellent flavor and higher nutritional value of crucian carp soup.
Co-reporter:Yaqin Hu, Rong Ji, Hai Jiang, Jinjie Zhang, Jianchu Chen, Xingqian Ye
Food Chemistry 2012 Volume 134(Issue 4) pp:2014-2020
Publication Date(Web):15 October 2012
DOI:10.1016/j.foodchem.2012.04.060
Cathepsin L (Cat L) in carp (Cyprinus carpio) dorsal muscles was purified and its molecular weight determined by SDS polyacrylamide gel electrophoresis (SDS–PAGE) was 36 kDa. Its optimal temperature and pH were 50 °C and 5.5, respectively. The results of the effects of specific substrates, activators and inhibitors on the enzymatic activity showed that Cat L belongs to the family of cysteine proteinases containing thiol. Compared to the control, the gel strength of surimi with the addition of purified Cat L decreased significantly by 24.33% while that of surimi with both purified Cat L and inhibitors increased by 13.7% and 21.6%, respectively, suggesting the participation of Cat L in the modori phenomenon occurring in carp surimi. Both the SDS–PAGE electrophoretic pattern and microstructure figure revealed that Cat L could hydrolyse the main protein in carp surimi and was one of the enzymes involved in the modori phenomenon.Highlights► Cathepsin L was purified from the dorsal muscles of carp (Cyprinus carpio). ► Cathepsin L was studied for its enzymatic characteristics. ► Cathepsin L could hydrolyse the main protein in carp surimi gel. ► Cathepsin L was one of the enzymes involved in the modori phenomenon.
Co-reporter:Jin-jie Zhang;Rong Ji;Ya-qin Hu
Journal of Zhejiang University-SCIENCE B 2011 Volume 12( Issue 9) pp:
Publication Date(Web):2011 September
DOI:10.1631/jzus.B1000251
Three cooking methods, namely boiling, steaming, and stir-frying for 5 to 10 min, were used to evaluate the effect on nutrient components, free amino acids, l-ascorbic acid, total phenolic contents, and antioxidant capacities of bamboo shoots (Phyllostachys praecox). Results showed that boiling and stir-frying had a great effect on the nutrient components and they decreased the contents of protein, soluble sugar, and ash, and caused a great loss in the total free amino acids (decreased by 38.35% and 34.86%, respectively). Significant differences (P<0.05) in free amino acids were observed in the samples cooked by different methods. Stir-fried bamboo shoots had a high fat content which increased by 528.57% because of the addition of edible oil. After boiling, the L-ascorbic acid and total phenolic contents were significantly reduced, while steaming increased total phenolic content by 3.98% and stir-frying well-preserved L-ascorbic acid (78.87% of its previous content). Results of the antioxidative property study showed that stir-frying could increase antioxidant capacities of bamboo shoots. It is concluded that stir-frying is more suitable for bamboo shoots because it could obtain the maximum retention of antioxidant capacities.
Co-reporter:Tiantian Wu, Chunhua Wu, Zhongxiang Fang, Xiaobin Ma, Shiguo Chen, Yaqin Hu
Food Control (September 2017) Volume 79() pp:317-324
Publication Date(Web):1 September 2017
DOI:10.1016/j.foodcont.2017.04.016
•CS-nisin microcapsules are prepared by the precipitation-coacervation technique.•The characteristics of CS-nisin microcapsules are discussed.•The shelf life of small yellow croaker is extended by CS-nisin microcapsules.Chitosan-nisin (CS-nisin) microcapsules were prepared and characterized. Its preservation properties (chemical stability, microbiological stability, color and sensory properties) were examined during the storage of small yellow croaker (Pseudosciaena polyactis). The results showed that CS-nisin microcapsules were spherical in shape with particle size greater than 1 μm. A significantly higher efficiency of CS-nisin microcapsules in inhibiting microorganism growth, lipid oxidation and protein degradation was observed, extending the shelf life of small yellow croaker during the storage by 6–9 days in comparision with CS, nisin treatment alone or the control according to the TVC assay, suggesting a better preservation effect of the microcapsules.
Co-reporter:Chun-hua WU, Chun-hong YUAN, Xing-qian YE, Ya-qin HU, ... Dong-hong LIU
Journal of Integrative Agriculture (December 2014) Volume 13(Issue 12) pp:2788-2806
Publication Date(Web):1 December 2014
DOI:10.1016/S2095-3119(14)60841-8
Aquatic product, known as one of the good resources for white meat, has been widely accepted by the consumers due to its high protein, low fat, especially low cholesterol. With the fast development of living standards around the world, the consumer demands for high quality, nutrition, safety and freshness of fishery food are increasing. Thus, high efficient preservation technologies for aquatic products become particularly important. Superchilling is one of the controlled-temperature preservation technologies for seafood. Aquatic products can be kept in better quality under superchilling conditions. This review introduced the principle and development of superchilling process, mainly focusing on research progresses and technical difficulties of superchilling. The growth mechanism of ice crystals and the feasibility of application of computational fluid dynamics in analyzing the temperatures variation and ice crystals during superchilling progress were also discussed, which will provide theoretical foundation for its improvement and application.
Co-reporter:Shalu Fu, Chunhua Wu, Tiantian Wu, Haixia Yu, Shuibing Yang, Yaqin Hu
Food Chemistry (15 April 2017) Volume 221() pp:
Publication Date(Web):15 April 2017
DOI:10.1016/j.foodchem.2016.11.123
•The CGA-Gel conjugate was fabricated for the first time.•CGA was grafted onto gelatin by forming amide bonds.•The antioxidant activity of CGA-Gel was proved to be enhanced during conjugation.•The possibility of applying CGA-Gel for seafood preservation was confirmed.Chlorogenic acid (CGA), a type of plant polyphenol, was conjugated onto gelatin (Gel) to prepare a novel coating material for the preservation of fresh seafood. The optimal reaction molar ratio of CGA to gelatin (4:1) was determined according to the CGA content in the CGA-Gel conjugate. CGA was confirmed to be successfully conjugated onto gelatin by 1H nuclear magnetic resonance and Fourier transform-infrared spectroscopy. The antioxidant activity of CGA-Gel was proven to be higher than that of the free CGA in 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) radical scavenging, hydrogen peroxide scavenging, ferric ion reducing power and lipid oxidation assays. The minimum inhibitory concentrations (MIC) of CGA against Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus were 1, 1, 2 and 2 mg/mL, respectively. The antibacterial activity of CGA-Gel was unaffected by conjugation.
