Spray-drying of bacteriocin-producing lactic acid bacteria

Area of Science:

• Food Microbiology
• Biotechnology
• Food Preservation

Background:

• Bacteriocins are antimicrobial peptides with potential as natural food preservatives.
• Spray-drying is a common method for preserving microbial cultures, but its effect on bacteriocin production and activity needs investigation.

Purpose of the Study:

• To evaluate the impact of spray-drying on the cell survival and bacteriocin activity of four lactic acid bacteria strains.
• To assess the stability of spray-dried bacteriocins during storage.

Main Methods:

• Four bacteriocin-producing lactic acid bacteria strains were spray-dried using skimmed milk or whey as suspension media.
• Inlet air temperatures (160-200°C) and flow rates (10-17 ml/min) were varied.
• Cell viability and bacteriocin activity were measured immediately after drying and during 60 days of storage at 4°C.

Main Results:

• Cell survival decreased with increasing inlet air temperature, regardless of the suspension medium.
• No loss of bacteriocin activity or production ability was observed immediately after spray-drying.
• Dried bacteria showed only temporary damage when exposed to NaCl.
• Bacteriocin activity remained stable during 60 days of storage, although cell survival gradually decreased.

Conclusions:

• Spray-drying is a viable method for preserving bacteriocin-producing lactic acid bacteria without compromising their antimicrobial activity.
• The resulting powders can be considered effective biopreservatives for food applications.
• Optimizing spray-drying conditions is crucial for maximizing cell survival.