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The application of growth-no growth models to directly assess the stability of wholemeal multigrain bread towards Penicillium paneum LMQA-002 and Paecilomyces variotii LMQA-001

dos Santos, Juliana Lane Paixão, Silva, Beatriz S., Furtado, Marianna M., Morassi, Letícia L.P., Vermeulen, An, Sant’Ana, Anderson S.
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2018 v.97 pp. 231-237
Paecilomyces variotii, Penicillium, breads, calcium propionate, growth models, pH, prediction, shelf life, spores, storage temperature
This study aimed to develop predictive models to assess the growth response of Pencillium paneum LMQA-002 and Paecilomyces variotii LMQA-001 in wholemeal multigrain bread regarding moisture, pH, calcium propionate, temperature and time of storage. A complete factorial design was performed using slices of bread with different formulation: moisture (36; 38; 40; 42%), pH (5.1; 5.3; 5.5) and calcium propionate (0.6; 0.8 and 1%). The slices were inoculated with 102-103 spores following storage at 20 °C, 25 °C and 30 °C for up to 21 days. The degree of agreement between predictions and observations was >90% for both species. According to the results, the growth of P. paneum LMQA-002 and P. variotii LMQA-001 was inhibited for up to 21 days in bread formulations presenting pH (5.1), 36% moisture and 0.6% calcium propionate. The lower temperatures (20 °C and 25 °C) contributed to the growth of P. paneum LMQA-002 and storage at 30 °C favored the growth of P. variotii LMQA-001. Validation results showed correct predictions in 80% of the cases. A significant achievement of this study comprises the extension of wholemeal multigrain bread shelf-life from 12 to 21 days (>70% increase).