Interactive effects of pH and temperature on the bacteriocin stability by response surface analysis

Area of Science:

• Food Microbiology
• Biochemistry
• Fermentation Technology

Background:

• Lactic acid bacteria (LAB) produce bacteriocins, natural antimicrobial peptides with potential as food biopreservatives.
• Understanding bacteriocin stability under various processing conditions is crucial for their effective application.
• Traditional fermented foods are rich sources of novel LAB strains and their bioactive compounds.

Purpose of the Study:

• To investigate the combined effects of pH and temperature on the stability of bacteriocins from Pediococcus pentosaceus MMZ26, Enterococcus faecium MMZ17, and Lactococcus lactis MMZ25.
• To determine optimal conditions for bacteriocin stability for enhanced application as biopreservatives.
• To elucidate the relationship between bacteriocin production and stability in food matrices.

Main Methods:

• Utilized a second-order orthogonal factorial design to study the influence of pH and temperature.
• Employed response-surface methodology (RSM) to analyze interactive effects and predict optimal stability conditions.
• Isolated and characterized bacteriocins from three specific LAB strains found in Tunisian traditional dry fermented meat.

Main Results:

• All three bacteriocins exhibited high heat stability.
• Optimal stability was observed at a slightly acidic pH of approximately 5.0.
• Effective stability was maintained at temperatures below 90°C with short incubation times.

Conclusions:

• The studied bacteriocins demonstrate significant stability under relevant food processing conditions (mildly acidic pH, <90°C).
• Findings support the in situ application of these bacteriocins as effective biopreservatives in fermented and heated food products.
• This research provides valuable insights for optimizing bacteriocin stability and utilization in the food and feed industries.