Alcohol precipitation mechanism and nanofiltration concentration process of phenolic acids from honeysuckle

Abstract Honeysuckle phenolic acids have pharmacological properties that are both antioxidant and anti-inflammatory. It is difficult to avoid phenolic acid oxidative degradation as a food raw material using the conventional alcohol precipitation and heating concentration technique. This study presents a method for preparing phenolic acids by alcohol precipitation coupled with nanofiltration (NF) that avoids phenolic acid transformation while keeping antioxidant properties. In alcohol precipitation, a mathematical model has been developed for adjusting the molecular proportion and transfer rate of phenolic acids by changing the pH of the alcohol solution. At room temperature, alcohol precipitation can be concentrated using a 300 Da NF membrane. When the phenolic acid transfer rate surpasses 93%, the concentration of alcohol in the filtrate remains constant, enabling continuous usage in the alcohol precipitation process. Furthermore, the phenolic acids have IC50 values of 42.68 μg/ml–59.47 μg/ml for DPPH· removal and 243.96 μg/ml–309.22 μg/ml for ABTS+ removal, and the alcohol precipitation coupled with NF effectively retained the antioxidant activity of honeysuckle phenolic acids. This paper presented a model for preparing honeysuckle phenolic acid, which provided a novel approach for future research on standardisation and control of the food preparation process.