Work

Development of a quality control method for postbiotics based on stable isotope dimethyl labeling and liquid chromatography-tandem mass spectrometry of heat-killed Lacticaseibacillus paracasei subsp. paracasei NTU 101

Year: 2025

Type: article

Abstract: Postbiotics, including inactivated probiotics, retain immune modulatory and gut health benefits while offering advantages in storage and transport. However, quality control (QC) of heat-killed probiotics in complex matrices remains challenging. In this study, we used proteomics based on mass spectrometry (MS) for protein identification and batch-to-batch consistency assessment of heat-killed Lacticaseibacillus paracasei subsp. paracasei NTU 101. Subsequently, the signature peptides of the two target proteins, 50S ribosomal protein L7/L12 and cell wall hydrolysis protein p40, were selected based on taxonomic discrimination and functional relevance for absolute quantification using stable isotope dimethyl labeling with liquid chromatography-MS and multiple reaction monitoring (LC-MS-MRM). This method was validated for both peptides, with quantification ranges of 0.5–100 ng/mL. L7/L12 showed 94–104% accuracy and 1–3% coefficient of variation (CV), with a limit of quantification (LOQ) of 0.3 ng/mL and limit of detection (LOD) of 0.1 ng/mL. p40 demonstrated 100–111% accuracy and 1–9% CV, with an LOQ of 0.6 ng/mL and LOD of 0.2 ng/mL. Both proteins demonstrated good linearity and reproducibility, supporting their suitability for postbiotic QC. Recovery experiments conducted by spiking milk powder matrix containing 5% heat-killed NTU101 probiotics showed recoveries of 87.99–89.49% for L7/L12 and 102.68–108.72% for p40, indicating reliable detection in high-protein formulations. Overall, this method provides a robust analytical tool for postbiotic QC in complex product matrices. The platform may serve as a reference framework for developing regulatory or industrial quality standards for postbiotic ingredients in functional food applications.

Source: LWT

DOI: 10.1016/j.lwt.2025.118368

Authors: Chia-Wei Wu, Tsung-Wei Shih, Tzu-Ming Pan

Institutions: Fu Jen Catholic University, National Taiwan University

Language: English

Topic: Probiotics and Fermented Foods

Subfield: Food Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,240