Potential of infrared drying and cell-protective agent efficiency on survival of Lactobacillus plantarum probiotic in fermented soybean meal

Abstract

The drying effectiveness of fermented soybean meal (FSBM) was studied using infrared radiation, with cell-protective agents and drying temperature explored to maintain Lactobacillus plantarum 7–40 probiotic survival during decreasing FSBM moisture content (MC). Results showed that maltodextrin (MTD) was suitable for protecting probiotic cells, similar to fructo-oligosaccharides (FOS). The MC of MTD-containing FSBM decreased faster than other cell protectants, while high temperature infrared drying (IRD) reduced the MC more quickly than low IRD temperatures, thereby impacting probiotic L. plantarum 7–40 survival. IRD decreased the MC of the FSBM to close 10% faster than hot air drying (HAD) at 40 °C by 10 h. Mathematical models were used to simulate the IRD profiles of FSBM. The Page and modified Page models simulated the schematic moisture ratio better than the other drying models. The thermal death kinetics of probiotic under IRD were not significantly different comparing HAD. In comparison, the effective diffusivity of IRD was greater than HAD by 2.6 times compared to 40 °C. The IRD at 40 °C was suitable for drying FSBM and provided higher energy consumption efficiency than conventional HAD. Findings suggested that applying MTD as cell-protective agent gave high probiotic survival and did not impact FSBM moisture removal of IRD. IRD delivered improved energy consumption efficiency compared to HAD as an attractive process for dehumidifying probiotic-based products.