Antibacterial properties of peptides from chia (Salvia hispanica L.) applied to pork meat preservation.

Chia-derived peptides might represent a novel alternative to conventional preservatives in food. Despite the antibacterial potential of these molecules, their food application is still limited. This study aimed to evaluate chia-derived peptides' antibacterial and antibiofilm potential in food preservation. The peptides YACLKVK, KLKKNL, KLLKKYL, and KKLLKI were synthesized, and their antibacterial activity against Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Salmonella Enteritidis was evaluated through microdilution tests. A bacterial killing kinetic assay determined bacterial growth over time. The ability to prevent and eradicate S. aureus biofilm was assessed by crystal violet staining. The hemolytic and cytotoxic activities were determined in human red blood cells and fibroblasts using free hemoglobin detection and (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assays, respectively. Finally, a microbial challenge was performed on meat samples inoculated with L. monocytogenes and S. Enteritidis to determine their inhibitory effects on pork meat. Results showed the potential antibacterial activity of these peptides, with minimum inhibitory concentrations ranging from 0.23 to 5.58 mg/mL. Biofilm inhibition percentages were above 40%, and eradication percentages were lower than 20%. In vitro assays in human red blood cells and fibroblasts demonstrated that peptides are not hemolytic or cytotoxic agents. In microbiological challenge testing, KKLLKI showed the most promising antibacterial effects against S. Enteritidis on refrigerated pork meat samples. These findings suggest that chia-derived peptides have the potential as natural food preservatives due to their antibacterial and antibiofilm properties. Notably, KKLLKI demonstrated promising antibacterial effects against Salmonella spp. on a complex food matrix, such as pork meat. PRACTICAL APPLICATION: Chia-derived peptides can be a safer alternative to synthetic preservatives in the food industry because the latter may be detrimental to human health. Salmonella spp. growth on chilled pork meat was shown to be inhibited by the peptide KKLLKI, indicating that the use of these peptides may offer a more secure and natural alternative to synthetic preservatives.

Antibacterial peptide fractions from chia seeds (Salvia hispanica L.) and their stability to food processing conditions.

Foodborne pathogens are one of the major causes of food deterioration and a public health concern worldwide. Antimicrobial peptides (AMPs) encrypted in protein sequences from plants, such as chia (Salvia hispanica), might have a crucial role in the inhibition of bacteria. In this study, the antibacterial activity and stability of chia peptide fractions (CPFs) were evaluated for potential applications in food preservation. Three CPFs (F < 1, F 1-3, and F 3-5 kDa) were obtained by enzymatic hydrolysis of a protein-rich fraction and subsequent ultrafiltration. Gram-positive bacteria were susceptible to F < 1. This fraction's more significant inhibition effect was reported against Listeria monocytogenes (635.4 ± 3.6 µg/mL). F < 1 remained active after incubation at 4-80 °C and a pH range of 5-8 but was inactive after exposure to pepsin and trypsin. In this sense, F < 1 could be suitable for meat and dairy products at a maximum reference level of 12-25 mg/kg. Multicriteria analysis suggested that KLKKNL could be the peptide displaying the antimicrobial activity in F < 1. These results demonstrate the potential of this sequence as a preservative for controlling the proliferation of Gram-positive bacteria in food products.

In silico prediction of peptide variants from chia (S. hispanica L.) with antimicrobial, antibiofilm, and antioxidant potential.

Plants are known as a rich source of bioactive peptides, and a variety of plant peptides have been studied as potential alternatives to conventional antimicrobial, antibiofilm, and antioxidant agents in food products to prolong their shelf-life, which could pose potential health risks for consumers. Regardless of their high functional potential, no plant peptides are currently used in the food industry for these purposes. In this study, it is performed the selection and optimization of peptides that are not currently reported in any database, derived from a chia peptide fraction. Computer-aided tools were used to identify multifunctional peptides with antimicrobial, antibiofilm, and antioxidant potential. Two peptide sequences (YACLKVK and KLKKNL) showing the highest probability scores for antimicrobial activity were identified from a total of 1067 de novo sequences in a chia peptide fraction (F<1 kDa). Subsequently, the peptides YACLKVK and KLKKNL were used to create scrambled libraries containing permutations of these sequences to explore the antibiofilm potential of different amino acid arrangements. The peptide variants with the highest probability scores for antibiofilm activity were subjected to optimization for the improvement of their activity. Finally, the optimized sequences were analyzed to determine the presence of antioxidant fragments. This computational approach could be a solution for the screening of a large number of peptides with more than one function, allowing the development of multifunctional peptides as alternatives to traditional food preservatives.