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

Abstract

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 peel during extraction. Lower than 2·0% of total of the N4 strain was recovered in juice extracted from inoculated oranges (about of 10(9 ) CFU ml(-1) ) under assayed conditions. After that, the N4 strain grew 2·43 ± 0·09 log cycles in 48 h 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. 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. The ability of this strain to survive in refrigerated juice without cause spoilage warrants further investigation to explore its potential use for biotechnology applications.