Project

Impact of microalgal proteins on the adhesion properties, release profile and biological activity of microporous scaffolds hosting probiotic living cells

Since the world population is anticipated to increase to 9.7 billion in 2050, the required dietary protein demand is likely to rise up to 1250 million tonnes (FAO, 2009; Henchion et al., 2017). One sustainable solution to satisfy the growing demand of dietary proteins is the substitution of animal derived proteins by plant proteins. Due to this, nutrient dense microalgae build an excellent source as they are high in protein (Caporgno and Mathys, 2018). The implementation of microalgal proteins in foods, nutraceuticals and cosmetics offer an excellent opportunity to replace animal proteins and be in alignment with the Farm-to-Fork strategy, which is implied in the European-Green Deal (Food 2030, EU Green Deal, Farm-to-Fork).
Incorporating living probiotic cells into structurally engineered soft matter (dry microparticulates, hydrogels, cryostructurates, etc), which is orally administered, is the commonest route for programming the bio-functionality of dietary supplements (Seifert et al., 2019). In general, milk proteins are considered as the golden standard for preserving the biological activity of a broad range of probiotic bacteria including Lactobacilli and Bifidobacteria (Gomand et al., 2019). Nevertheless, the use of milk proteins in food supplements may impose significant constraints such as allergenicity, high carbon footprint and low sustainability, or exclusion of specific consumer groups (e.g., veganism, ethical issues associated with cultural or religious background etc.) (Henchion et al., 2017). To avoid the aforementioned issues and to meet the ever-growing consumer demand for sustainable and healthy dietary proteins, the utilisation of microalgal protein in food and nutraceutical product development offers excellent innovation opportunities.

Aim
The main goal of the ALGPRO project is to design, develop and mechanistically investigate the ability of microalgal protein isolates obtained from at least three microalgal species (Chlorella, Galdieria and Arthrospira) as novel bio-preserving agents in microporous xero-scaffolds conveying different strains of living probiotic cells (Lactobacilli and/or Bifidobacteria species) of diversified cellular surface organisation.

Approach
The mechanisms involved in the ability of microalgal proteins to promote the resistance of the living probiotic cells under diverse extrinsic stressors associated with processing and storage, i.e., thermal, osmotic or oxidative shock, will be studied comparatively to the well-studied milk proteins i.e., whey protein isolate and sodium caseinate. In addition, the interactions between the colloidal transformation (disintegration and release profile) of the conveying xero-vehicles and the sub-lethality of the Lactobacilli cells under simulated (static or semi-dynamic) in vitro digestion conditions will be investigated. Furthermore, the Lactobacilli/ Bifidobacteria cell adhesion biophysics using diverse adhesion models (co-culture cell model vs pig intestinal epithelium), will be part of the investigations. Finally, the growth kinetics and volatilome changes under anaerobic conditions using a synthetic microbial gut system spiked with the dialysed intestinal digesta will also be tracked down.

References
1. Caporgno, M.P., Mathys, A., 2018. Trends in Microalgae Incorporation Into Innovative Food Products With Potential Health Benefits. Front. Nutr. 5, 58.
2. Gomand, F., Borges, F., Guerin, J., El-Kirat-Chatel, S., Francius, G., Dumas, D., Burgain, J., Gaiani, C., 2019. Adhesive Interactions Between Lactic Acid Bacteria and β-Lactoglobulin: Specificity and Impact on Bacterial Location in Whey Protein Isolate. Front. Microbiol. 10.
3. Henchion, M., Hayes, M., Mullen, A.M., Fenelon, M., Tiwari, B., 2017. Future Protein Supply and Demand: Strategies and Factors Influencing a Sustainable Equilibrium. Foods 6, 53.
4. Seifert, A., Kashi, Y., Livney, Y.D., 2019. Delivery to the gut microbiota: A rapidly proliferating research field. Adv. Colloid Interface Sci. 274, 102038.