ICDSUPL4-H004

Volume: 4, 2025
4th International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT

Abstract number: H004

DOI: https://doi.org/10.24326/ICDSUPL4.H004

Published online: 9 April 2025

ICDSUPL, 4, H004 (2025)

In vitro digestion of soups. A standardized approach to simulating gastrointestinal processes and bacterial viability

Dorota Gajowniczek-Ałasa¹*, Ewa Baranowska-Wójcik¹, Klaudia Gustaw¹, Joanna Grzelczyk², Dominik Szwajgier¹

¹ Department of Biotechnology, Microbiology and Human Nutrition University of Life Sciences in Lublin, Skromna 8, 20-704 Lublin, Poland

² Lodz University of Technology, Stefanowskiego 2/22, 90-537 Łódź, Poland

^{* Corresponding author: dorota.gajowniczek@up.lublin.pl}

Abstract

This study investigates the in vitro digestion of four soups—functional foods specifically developed in our laboratory to support the early prevention of Alzheimer’s disease. The digestion process was carried out using a standardized protocol adapted from Brodkorb et al. (2019), which simulates the physiological conditions of the human gastrointestinal tract in a controlled laboratory setting. This approach allows for a detailed examination of nutrient bioaccessibility, microbial interactions, and bacterial viability throughout digestion. To mimic human digestion, the soups were subjected to a sequential multi-phase digestion process, including oral, gastric, small intestine, and large intestine phases. Each phase was carefully designed to replicate physiological conditions by incorporating relevant digestive enzymes, fluids, and environmental parameters such as temperature and pH. Specifically, a 50 mL aliquot of each soup was exposed to controlled digestion conditions, including the addition of salivary α-amylase in the oral phase, gastric pepsin in the stomach phase, and a mixture of pancreatin and bile salts in the small intestine phase. The final large intestine phase involved microbial inoculation to assess the interactions between digested soup components and gut microbiota. To investigate bacterial viability, we introduced a probiotic inoculum (Jarro Dophilus formulation) into the large intestine phase and monitored its survival under simulated gut conditions. The viability of these probiotic strains was assessed before and after 24 hours of anaerobic incubation at 37°C, using the plate count method with MRS and Garche media to specifically target Lactobacillus and Bifidobacterium strains. To ensure the accuracy and reliability of the experiment, triplicate samples were collected both at the start (time zero) and after 24 hours of digestion. A reagent control (digestion fluids without soup) was included to validate the experimental setup and rule out any background microbial activity unrelated to the test samples. To monitor bacterial growth in the large intestine phase, samples were collected in triplicate at time zero and after 24 hours of digestion. To minimize aeration throughout digestion, CO₂ infusion and peristaltic pump delivery of additives were applied. The findings of this study contribute to a deeper understanding of nutrient bioaccessibility, microbial interactions, and bacterial viability during the digestion of liquid food matrices.

Keywords: in vitro digestion, bacterial growth, experimental validity

How to cite

D. Gajowniczek-Ałasa, E. Baranowska-Wójcik, K. Gustaw, J. Grzelczyk, D. Szwajgier, 2025. In vitro digestion of soups. A standardized approach to simulating gastrointestinal processes and bacterial viability. In: 4th International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL4.H004