Properties Studies Of Fluorescent Nanodots In The Roast Process Of Chicken

Chicken,an excellent source of protein and trace elements,is the second-most consumed meat in the world.Roasted chicken has a unique flavor and taste created by open flames and radiant heat,which is very popular.During the roast process,chicken meat undergoes a series of complicated physicochemical reactions to form nano-scale structures.These nano-scale structures have special fluorescent properties.These nanoscale particulate matters also cause public concern due to their special properties.In this paper,chicken breast was selected as raw material to study the physicochemical properties.The formation and physicochemical properties of a class of fluorescent nanodots(FNDs)in roasted chicken were investigated.To determine the generation of FNDs in the roast chicken,the change of the basic material composition of roasted chicken in different temperature(150?300 ?)was investigated.As the roast temperature increaseed,the basic nutrient composition of chicken was changed.The moisture content of chicken meat decreased from 73.9%to 7.13%,and the protein content decreased from 18.9%to 15.7%,at the 300 ?.The water-soluble protein was greatly lost,the fat content decreased from 4.7%to 4.2%,and the sugar content changed little.The transverse relaxation(T₂)spectrum showed that a decreasing trend with the increase of the roasting temperature.At the roasting temperature of 300°C,a small peak appeared at?1.75 ms indicating reduced water mobility in the sample,possibly due to the contraction of the myofibrillar space.The microscopic morphology of such FNDs was spherical,and as the roasting temperature increased from 200 to 300°C the size of the FNDs decreased,significantly,from 17.1 to 2.1nm.The FNDs,which mainly contain carbon(60-80%),were strongly fluorescent under ultraviolet light,exhibiting an excitation-dependent emission behavior.The fluorescence quantum yields of the FNDs were determined at 200,250,and 300°C,and were found to be6.71±0.21,12.85±0.34 and 17.46±0.42%,respectively.During the roast process,the chicken myofibrils were first shrinked and hydrolyzed to form a relatively large polymer cluster.As the roast temperature increaseed,the oxidation reaction intensified,resulting in a polymer-like polymer.The spherical carbon FNPs were finally formed under the continuous action of the carbonization reaction.Cell experiments showed that the FNDs could be taken up by Hep G₂ cells,which were distributed in the cytoplasm.When the concentration of FNDs reached 4 mg/m L,the relative cell viability decreased by 37%,and the relative concentration of lactate dehydrogenase(LDH)remained unchanged,indicating that FNDs had potential cytotoxicity but did not cause serious damage to the cell membrane.In vivo imaging experiments of mice demonstrated that FNDs could enter the body of mice to emit strong fluorescence.The FNDs were metabolized after 22hours in mice.The large intestine,small intestine and the brain were the main organs of absorption.In vitro simulation digestion experiments showed the FNDs could reduce the digestibility of soy protein isolated from 95.75 to 80.82%.Human serum albumin(HSA)was used as a macromolecular substance model,and dopamine(DA)was used as a small molecule model to investigate the interaction between FNDs with HSA and DA.The fluorescence of HSA was quenched by the FNDs following a static mode,and the molecular interaction of nanoparticles with HSA was spontaneous(?G₀<0),where hydrogen bonding and van der Waals forces played an important role during HSA-FNDs complex stabilization through thermodynamic analysis by isothermal titration calorimetry.The principal location of the nanoparticles binding site on HSA was site I as determined by site-specific marker competition.When the ratio of FNDs to HSA reached 100:1,the?-helical structure of HSA reduced by 4%.The results of the fluorescence and fourier transform infrared spectroscopy(FTIR)analysis indicated that the FNDs could interact with the neurotransmitter DA in vitro through the formation of fluorescent conjugates.The above results confirmed the existence of FNDs in roasted chicken,revealed their formation mechanism,and provided a new idea for reducing the adverse effects of chicken and improving their quality.Systematically exploration of the security of FNDs and their potential biological effects on living organisms provided reference for risk assessment of food-borne NPs spontaneously produced in meat processing.