Investigation on shelf-life of roasted chestnuts with different packaging systems through low-field NMR analysis

Raw chestnut has a limited shelf life due to the high moisture content. Diverse processing methods have been employed to make chestnut palatable and safe for consumption. Roasting is considered a suitable process for maintaining the nutritional profile and minimising the loss of nutrients of chestnut, but the residual moisture content does not assure a prolonged shelf life. To this aim, two different packaging methods are compared in this work, specifically a modified atmosphere package and a semipermeable film. The weight loss and the O2 and CO2 concentrations were measured during time. Moreover, low-field 1 H NMR single-sided relaxometry was used to have information on water compartments, diffusion and movement obtained by detecting proton signals prevalently ascribable to H2O contained in chestnuts. The main advantage of this technique is that it does not require any pre-treatment of the sample, it is non-invasive and hence chestnut sample is here analysed within its packaging system during shelf life. Results showed that modified atmosphere packaging allowed the roasted chestnut to be marketable up to 90 days, while the semipermeable film up to 30 days.