| Due to the harm of synthetic antioxidants to human health,developing a stable and highly bioactive natural antioxidant has become a hot topic in the field of food research to ensure food safety.Chlorogenic acid is a plant derived polyphenol,colorless and odorless,with strong antioxidant and antibacterial effects.It is one of the most suitable candidate materials for building natural antioxidants.However,chlorogenic acid has poor lipid solubility,unstable structure,and low bioavailability,which greatly restricts its application in the food industry.Therefore,we try to wrap it with chitosan modified liposomes.The wrapped chlorogenic acid can reduce the direct effect of external factors to a certain extent,while utilizing the slow release property of liposomes to avoid rapid consumption of chlorogenic acid,thereby achieving the effect of increasing the stability of chlorogenic acid molecules and extending their action time.The specific research and experimental findings are as follows:(1)The effect of chlorogenic acid and chlorogenic acid liposomes on the oxidation and bacterial inhibition of preserved fish was investigated by measuring the changes in p H,POV and TBARS values of preserved fish during storage and investigating the effect of different concentrations of aqueous chlorogenic acid and chlorogenic acid liposomes on the quality of preserved fish.The effects of different concentrations of chlorogenic acid aqueous solution and chlorogenic acid liposomes on the quality of the fish were investigated.The experimental results showed that both aqueous chlorogenic acid and liposomal chlorogenic acid had certain antioxidant effects on the fish during storage,and the liposomal group had better antioxidant properties than the aqueous group when the amount of chlorogenic acid was added.The antioxidant effect was dose-dependent when added in the range of400-800 mg/kg,however,the ability to inhibit lipid oxidation was reduced when chlorogenic acid was added at too high a level(1000 mg/kg).(2)The predominant bacterial groups and their distribution ratios in different groups of preserved fish were investigated by traditional microbial culture and high-throughput sequencing techniques.The abundance of Staphylococcus spp.,Megacoccus spp.,Bacillus spp.,Pseudomonas spp.,Cryptozoa spp.and Immunobacterium spp.in the fish samples was confirmed.Among them,chlorogenic acid had a strong inhibitory effect on Staphylococcus spp.,Megacoccus spp.and Bacillus spp.The dominant bacterial groups and their distribution ratios differed in different groups of waxy fish.In the chlorogenic acid aqueous solution group,the antimicrobial activity of chlorogenic acid was poorer at low concentrations(chlorogenic acid added at 400 mg/kg)and high concentrations(chlorogenic acid added at 1000 mg/kg),and in the chlorogenic acid liposome group,the antimicrobial ability was poorer at high concentrations of chlorogenic acid liposomes(chlorogenic acid added at 1000 mg/kg).When chlorogenic acid concentration was fixed,the antimicrobial activity of the chlorogenic acid liposome group was better than that of the chlorogenic acid aqueous solution group.Among all waxy fish samples,the liposome group with a chlorogenic acid addition of 800mg/kg had the strongest antimicrobial activity.(3)Chitosan chlorogenic acid liposomes(CL-3,CL-4,CL-5)of different concentrations were prepared by using chitosan(3.0,4.0,and 5.0 mg/ml)in different concentrations and wrapping them in the outer layer of chlorogenic acid liposomes through electrostatic interaction.The stability of different particles was investigated by comparing the potential,particle size distribution,encapsulation efficiency,and release rate within 60 hours of liposomes.The results showed that the particle size distribution of CL-3 and CL-4 was more concentrated,and the absolute value of Zeta potential was larger.However,there were double peaks in the particle size diagram of chlorogenic acid liposomes coated with high concentration of chitosan,and the absolute value of Zeta potential was lower,indicating that the stability of chlorogenic acid liposomes modified with high concentration of chitosan was poor.In vitro release experiment,at 12 hours,the release of L was 84.63±1.75%,and the release of CL-5 was 69.51±3.28%,while the release of CL-3 and CL-4 were37.85±1.52% and 47.97±2.11%,respectively.It can be seen that the release of CL-3and CL-4 is significantly lower than that of L and CL-5,and the release of CL-3 is the lowest.This result again confirms that the stability of chlorogenic acid liposomes modified by high concentration of chitosan is poor.(4)Four groups of solutions,L,CL-3,CL-4,and CL-5,were coated on the surface of cured fish.The changes in p H,total bacterial count,lipid oxidation,fatty acids,color,and texture of cured fish during storage for 40 days were measured.The experimental results confirmed that the quality of cured fish in CL-3 and CL-4groups was better,so we thought that the chlorogenic acid liposome coated with chitosan at the concentration of 3.0 and 4.0 mg/ml had the strongest antibacterial and antioxidant ability. |
PDF Full Text Request