Open AccessHeat-treatment as a measure for microbiological quality improvement of walnuts and peanuts
Author(s) -
Bernadeta Žudytė,
Sigita Ramonaitė
Publication year - 2017
Publication title -
žemės ūkio mokslai
Language(s) - English
Resource type - Journals
eISSN - 2424-4120
pISSN - 1392-0200
DOI - 10.6001/zemesukiomokslai.v24i2.3498
Subject(s) - roasting , food science , chemistry , inoculation , incubation , petri dish , microorganism , horticulture , biology , microbiology and biotechnology , bacteria , biochemistry , genetics
The aim of this research was to evaluate the influence of heat-treatment on the microbiological indexes of walnuts and peanuts.Two separate experiments were performed; each of them was replicated 3 times. Walnuts were blanched with 40, 60, 80 and 100 °C water for 1, 2 and 5 min. Peanuts were roasted at 100, 110 and 120 °C for 20, 40 and 60 min. The prepared samples were inoculated in disposable Petri dishes with the DG18 medium and held for 5 days at 25 °C temperature. After the incubation the amount of moulds was quantified.The experiment showed that the heat-treatment of ≥80 °C completely destroyed moulds in walnuts, the heat-treatment of 60 °C was effective for reducing of microorganisms, and the heat-treatment of 40 °C only slightly reduced their number (p 0.05).Both analysed factors were significant for roasted peanuts (p > 0.05). The number of moulds was reduced by 51.47% after roasting peanuts for 20 min at 100 °C. Despite the fact that roasting is an effective method to reduce the number of microorganisms, moulds were completely destroyed only in one sample, which was roasted at 120 °C for 60 min.