Non-thermal treatment for the stabilisation of liquid food using a tubular cellulose filter from corn stalks

Abstract

Thermal pasteurisation is used for the microbial stabilisation of foods, but this process compromises quality food properties. This study proposes a novel cold preservation method with filtering materials obtained from agricultural by-products. Nano/micro-porous cellulose materials from native corn stalks (NCS), and the material obtained after delignification, were used as filtering materials for the microbial stabilisation of water and orange juice. The optimisation study of NCS and corn stalk tubular cellulose material (CSTC) to remove yeast Saccharomyces cerevisiae and Lactobacillus casei from water in accordance with processing variables was firstly conducted. Optimisation tests demonstrated the influence of cell concentration, filter size and flow rate on filter removal yields. Then the continuous filtration of commercial orange juice was performed for 20 days to remove S. cerevisiae. The results showed that delignified CSTC was an effective filtering material for removing S. cerevisiae and L. casei from water, and it successfully treated commercial contaminated orange juice. Despite juice colour diminishing when the process started and after filter regeneration cycles with hot water, almost initial parameter values were obtained as the process continued. Therefore, the proposed filtering material is a promising low-cost alternative to existing thermal pasteurisation technologies for liquid foods.