M B Perez1, F M Saguir. 1. Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho, Tucumán, Argentina.
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 peel 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(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. 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.
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 peel 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(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. 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.