Transfer and subsequent growth and metabolism of Lactobacillus plantarum in orange juice medium during storage at 4 and 30°C

Abstract

Aim: To investigate the physicochemical changes produced from growth and metabolism of Lactobacillus plantarum N4 in orange juice medium stored at 4 and 30°C after transferring from artificially inoculated oranges peal during extraction. Methods and Results: Lower than 2·0% of total of the N4 strain was recovered in juice extracted from inoculated oranges (about of 10 9CFUml -1) under assayed conditions. After that, the N4 strain grew 2·43±0·09 log cycles in 48h at 30°C. Sugars such as glucose and fructose and l-malic and citric acids were utilized, although at different rates and extent, yielding significant lactate and acetate amounts with a concomitant pH reduction. Ethanol, diacetyl, acetoin or 2,3 butilenglicol were undetected. During juice storage at 4°C bacterial counts, sugars composition and pH remained significantly unchanged as well as its sensory attributes. Conclusion: The transfer rate of L. plantarum N4 to freshly squeezed juice under adequate hygienic condition was low. At 30°C, the micro-organism rapidly initiated growth, producing acids but not butter flavour compounds neither ethanol. Significance and Impact of the Study: The ability of this strain to survive in refrigerated juice without cause spoilage warrants further investigation to explore its potential use for biotechnology applications. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.