Auteurs : Guillaume Quang N'guyen, Cyril Roblet, Luc Lagacé, Marie Filteau
Cet article est disponible seulement en anglais (Front. Syst. Biol., 29 April 2022).
Maple syrup, an emblematic food product of Canada is produced from the concentration of sap collected from maple trees during spring. During this season, the trees come out of dormancy, which modifies sap composition. Meanwhile, microorganisms that contaminate sap as it is collected can also modify its composition. As these two factors can impact the quality of maple syrup, we aimed to better understand how microbial communities vary along dormancy release. We estimated the absolute abundance of bacteria and fungi in maple sap along a dormancy release index using high-throughput amplicon sequencing and digital droplet PCR (ddPCR). Several members were identified as indicators of maple sap composition, syrup organoleptic conformity and color, some of which are also hubs in the microbial association networks. We further explored bacterial communities by performing a predictive functional analysis, revealing various metabolic pathways correlated to dormancy release. Finally, we performed an experimental investigation of maple sap carrying capacity and limiting nutrients along dormancy release and found that maple sap composition variation influences its carrying capacity. Taken together, our results indicate that an increase in nitrogen supply in the form of allantoate combined with possible metabolite excretion could lead microbial communities towards different paths. Indeed, we observed a greater heterogeneity during late dormancy release which in turn could explain the variation in maple syrup quality. Further experimental investigation into the contribution of microbial, vegetal, environmental, technological, and processing factors to the final composition of maple syrup will be required to improve our understanding of this complex and flavorful food matrix and to develop quality control strategies.(4080167)
Auteurs : Fadi Ali, Jessica Houde, Carmen Charron, Mustapha Sadiki
Cet article est disponible seulement en anglais (Food Control, Vol. 131, January 2022, 108450). Le numéro de référence (Digital Object Identifier (DOI)) est le : 10.1016/j.foodcont.2021.108450.
Maple syrup is produced typically from maple sap concentrated by nanofiltration or reverse osmosis at a moderate °Brix level ranging from 6 to 16 °Brix followed by heat evaporation. Recently, new membrane processes have been developed to concentrate maple sap to ultra-high °Brix reaching up to 40 °Brix. The aim of this study is to evaluate the effect of this ultra-high concentration of sap on the composition, the properties and the cost of corresponding maple syrup. Results showed some differences in chemical composition and properties between syrups produced from low and ultra-high concentration of sap. Syrups produced from ultra-high °Brix concentrated sap had lower concentrations of potassium and polyphenols, a lighter color and distinctive flavor. This was mainly observed when no modification were applied to the heating pattern in the evaporator pans. However, syrups produced by modulation of the heating pattern in the evaporator had color, flavor and taste similar to control syrups. These results demonstrate that syrups with comparable sensory properties can be obtained from low and ultra-high concentrated sap by adjusting the heating time depending on the initial °Brix. The concentration process to ultra high °Brix allows for a concomitant reduction of the production costs and a modulation of syrup quality. (4010119)
Auteurs : Fadi Ali, Jessica Houde, Carmen Charron, Mustapha Sadiki
Cet article est disponible seulement en anglais (Food Control, Vol. 123, May 2021, 107728). Le numéro de référence (Digital Object Identifier (DOI)) est le : 10.1016/2020.107728.
Abstract
Nanofiltration and Reverse Osmosis are membrane concentration processes originally used by maple syrup producers to preconcentrate the sap to a moderate °Brix level (8–16 °Brix). The purpose of this study is to evaluate the potential of new membrane technology to concentrate maple sap to ultra-high °Brix and to investigate the effect of this concentration on the chemical composition and physical properties of final sap concentrate. Maple sap was concentrated up to 42 °Brix using two industrial membrane units. The contents of main solutes increased with the °Brix of concentrates depending on the specific rejection rate of the membranes tested. A slight and significant decrease was observed in the availability of some solutes such as K+, Mn++ and polyphenols in ultra-high-concentrated sap. However, the apparent organoleptic and physical properties of these concentrates have not been altered. According to the results of this, the new membrane process allows to produce ultra-high °Brix concentrate of maple sap with interesting properties. However, further works have to be performed on this technology to more precisely determine the highest °Brix level that will minimise the affect on chemical composition and properties of concentrated sap and the corresponding maple syrup. (4010119)