Auteurs : Luc Lagacé, Réjean Gaudy, Carolina Locas-Perez et Mustapha Sadiki.
Cet article est disponible seulement en anglais (The Journal of AOAC INTERNATIONAL, Volume 95, Number 2, March-April 2012, pp. 394-398(5)).
The occurrence of formaldehyde in sap and wood tissue of treated and untreated maple sugar trees was investigated using GC/MS. Samples were collected at different periods of the 2009 season and at different locations in Quebec, Canada. The natural concentration of formaldehyde found in untreated samples varied according to periods and locations and ranged from below the LOQ to 1.82 mg/kg for sap samples and from 2.39 to 8.92 mg/kg of fresh tissue for wood samples. Late season samples tended to have higher concentrations of formaldehyde. Samples of sap and wood tissue from tapholes treated with solutions of formaldehyde showed increased concentrations of formaldehyde for many days after treatment and were clearly distinct from untreated samples. These results will be useful to elaborate new inspection procedures for sugarbushes to control the illegal use of formaldehyde.
Auteurs : Marie Filteau, Luc Lagacé, Gisèle LaPointe et Denis Roy.
Cet article est disponible seulement en anglais (Food Microbiology, Volume 28, Issue 5, August 2011, Pages 980–989). Le numéro de référence (Digital Object Identifier (DOI)) est le : 10.1016/j.fm.2011.01.008.
During collection, maple sap is contaminated by bacteria and fungi that subsequently colonize the tubing system. The bacterial microbiota has been more characterized than the ungal microbiota, but the impact of both components on maple sap quality remains unclear. This study focused on identifying bacterial and fungal members of maple sap and correlating microbiota composition with maple sap properties. A multiplex automated ribosomal intergenic spacer analysis (MARISA) method was developed to presumptively identify bacterial and fungal members of maple sap samples collected from 19 production sites during the tapping period. Results indicate that the fungal community of maple sap is mainly composed of yeast related to Mrakia sp., Mrakiella sp., Guehomyces pullulans, Cryptococcus victoriae and Williopsis saturnus. Mrakia, Mrakiella and Guehomyces peaks were identified in samples of all production sites and can be considered dominant and stable members of the fungal microbiota of maple sap. A multivariate analysis based on MARISA profiles and maple sap chemical composition data showed correlations between Candida sake, Janthinobacterium lividum, Williopsis sp., Leuconostoc mesenteroides, Mrakia sp., Rhodococcus sp., Pseudomonas tolaasii, G. pullulans and maple sap composition at different flow periods. This study provides new insights on the relationship between microbial community and maple sap quality.