Proteomic and peptidomic profiling of spirulina-fortified probiotic powder formulations during in vitro digestion.

This study reports on the influence of lactic acid fermentation on the proteomic and peptidomic profiles of spirulina protein isolate (SPI)-fortified, freeze-dried powders containing living Lacticaseibacillus rhamnosus GG (LGG) cells during in vitro digestion. For comparison, powders fortified with whey protein isolate (WPI) and pea protein isolate (PPI) were also evaluated. Prior to freeze-drying, the powder precursors were either non-treated or fermented. Capillary SDS-PAGE electropherograms revealed a mild proteolytic effect due to fermentation. C-phycocyanin (SPI) and β-lactoglobulin (WPI) showed the highest resistance to pepsinolysis. All samples were responsive to pancreases, with fermented WPI showing the lowest responsiveness. Fermentation enhanced the degree of hydrolysis (DH) in gastric chymes, whereas in intestinal chymes, DH followed the order SPI > PPI > WPI, with fermentation showing no significant impact. A total of 6, 11, and 52 potential bioactive peptide sequences, associated with various beneficial activities, were identified in the SPI, PPI, and WPI digesta, respectively. The highest amino acid bioaccessibilities were observed for cysteine and methionine in SPI, isoleucine and arginine in PPI, and glycine in WPI. In conclusion, fortifying probiotic formulations with protein isolates offers secondary health benefits, stemming from the release of bioactive peptides and bioaccessible essential amino acids.
Competing Interests: Declaration of competing interest PM International AG had no influence on the study design, data collection and analysis, decision to publish, or preparation of the manuscript. LIST affiliated authors declare that the research was conducted in the absence of any financial relationships that could be construed as a potential conflict of interest.
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