Chestnut purée: a possible growth media for probiotic microorganisms ¿ Preliminary results Conference Paper uri icon


  • FCl, Portugal[CIMO: UID/AGR/00690/2019]; Portugal 2020 [Go_ClimCast Project: PDR2020- 1.0.1-FEADER-032060]
  • Portugal and Spain are important chestnut producers. It is crucial to valorize this nut by using small-size and broken fruits that are usually discarded or used to produce animal feed. In this way, the production of chestnut purés seems to be an excellent alternative to valorize these fruits. Considering that chestnut does not contains lactose and its gluten-free, the present work aimed to use chestnut purée as a growth medium for probiotic microorganisms to obtain in the future a probiotic product that lactose-intolerants and celiac people could consume. In the present work, chestnut purées were produced and inoculated with Lactobacillus casei subsp. casei CECT 4043, Lactococcus lactis subsp. lactis CECT 539 and kefir grains. The following parameters were determined: Colony forming units per millilitre (CFU/mL), pH, total sugars, protein, total phosphorous and total nitrogen. Previously, a rheologic study was also performed to understand the flow behaviour of the chestnut purée when subjected to different temperatures (15, 25, 50 and 75 °C). The chestnut purée showed a pseudoplastic behaviour, as the viscosity decreased with the shear rate. Nevertheless, at the lowest temperatures, some time-dependency was observed. A hysteresis was detected between the loading and unloading curves, suggesting the existence of thixotropy. However, this behaviour was not so evident at high temperatures at 50 and 75 °C. Furthermore, the viscosities of chestnut purées decreased with temperature due to starch gelatinization. Regarding the growth of the microorganisms, Lb. casei and L. lactis reached approximately 109 and 108 UFC/mL of chestnut purée, respectively, after 26 hours fermentation. Concerning the fermentation with kefir, bacterias and yeasts were detected, being the first in higher number than the second at the end of fermentation. At this time, bacteria counts higher than 107 UFC/mL of chestnut purée were achieved. In all fermentations, it was observed a reduction in pH. The initial pH of the chestnut purée was around 6.4, decreasing to 4.7 for Lb. casei and L. lactis, or 3.7 for the kefir grains, at the end of the fermentation. In conclusion, the chestnut purée seems to be a good growth media for probiotic microorganisms.

publication date

  • January 1, 2021