Junhua Li

Bio: Junhua Li is an academic researcher from Jiangnan University. The author has contributed to research in topics: Chemistry & Egg white. The author has an hindex of 17, co-authored 62 publications receiving 742 citations. Previous affiliations of Junhua Li include RMIT University.

Magnetic particles for separation and purification of nucleic acids

Abstract: Nucleic acid separation is an increasingly important tool for molecular biology. Before modern technologies could be used, nucleic acid separation had been a time- and work-consuming process based on several extraction and centrifugation steps, often limited by small yields and low purities of the separation products, and not suited for automation and up-scaling. During the last few years, specifically functionalised magnetic particles were developed. Together with an appropriate buffer system, they allow for the quick and efficient purification directly after their extraction from crude cell extracts. Centrifugation steps were avoided. In addition, the new approach provided for an easy automation of the entire process and the isolation of nucleic acids from larger sample volumes. This review describes traditional methods and methods based on magnetic particles for nucleic acid purification. The synthesis of a variety of magnetic particles is presented in more detail. Various suppliers of magnetic particles for nucleic acid separation as well as suppliers offering particle-based kits for a variety of different sample materials are listed. Furthermore, commercially available manual magnetic separators and automated systems for magnetic particle handling and liquid handling are mentioned.

Protein–polyphenol conjugates: Antioxidant property, functionalities and their applications

Abstract: Background Proteins from different sources serve as primary food components, while polyphenols, as secondary metabolites, are abundantly present in plant. Both components play an important role in functional properties and quality of food products. Interaction between proteins and polyphenols, yielding “protein-polyphenol conjugate”, spontaneously occurs in most of food systems, and is known to have an impact on sensorial, functional, and nutraceutical properties of the food products. Scope and approach Protein-polyphenol conjugate can be implemented for improvement of food quality. In this article, mechanism and factors affecting protein-polyphenol interactions as well as the functionalities of protein-polyphenol conjugates, especially solubility, thermal stability, emulsifying, gelling and antioxidant properties, are revisited. The information on potential applications of protein-polyphenol conjugates in emulsions, protein-based films, and protein gels, as well as conjugates-based delivery systems is also discussed and reviewed. Key findings and conclusions The interaction of proteins and polyphenols mainly results from non-covalent (H-bonding, electrostatic interactions) or covalent bonds taking place mostly based on the oxidation of proteins or polyphenol by enzymatic or non-enzymatic pathways. Moreover, protein-polyphenol interaction greatly depends on environmental conditions such as temperature and pH as well as on the conformation or type of proteins and polyphenols. The protein-polyphenol conjugates with higher thermal stability, antioxidant activities, better emulsifying properties and enhanced gelling property can be used as novel food additives for improvement of functionalities and quality of food products.

Rheological, texture and sensory properties of low-fat mayonnaise with different fat mimetics

Abstract: Application of whey protein isolate and low-methoxy pectin-based fat mimetics in mayonnaise was studied. Fat was partially substituted by different fat mimetics at levels of 50%, respectively, which the fat mimetics were referred to as PFM1 (microparticulate pectin gel), PFM2 (pectin weak-gel), and PFM3 (microparticulated combination of WPI and pectin). The full fat (Ff) (100% oil) mayonnaise without fat mimetic was used as a control experiment. Physicochemical, rheological, texture analysis, and sensory evaluation of the Ff and low fat (Lf) mayonnaises were performed. The results indicated that all Lf mayonnaises had significantly lower energy content, but higher water content than their Ff counterpart. In terms of texture, the formulation with pectin weak-gel as fat mimetic showed similar texture values as those of the Ff sample. Both Ff and Lf mayonnaises exhibited thixothopic shear thinning behaviour under steady shear tests and were rheologically classified as weak gels under small amplitude oscillatory shear tests. Sensory evaluation demonstrated that mayonnaises substituted with low-methoxy pectin were acceptable. This study shows good potential for pectin weak-gel and microparticulated pectin gel to be used as a fat mimetic in mayonnaise.