Biopreservation strategies: Can organic acid concentrations be sufficient to predict yeast and mould growth in strawberry purée?

With growing demand for healthier food without additive, biopreservation offers a promising alternative. However, most studies focus on its effectiveness rather than the development of biopreservation strategy. To address this, a modeling-based approach was used to design a biopreservation solution for strawberry purée.

A predictive model was developed to assess the growth of spoilage yeasts and moulds in strawberry purée in the presence of organic acids (OAs). For model development and evaluation, minimum or least inhibitory concentrations (MIC, LIC) of lactic, acetic, propionic, sorbic, and benzoic acids were determined for representative spoilage strains for strawberry (Saccharomyces uvarum, S. paradoxus, Rhodotorula glutinis and Botrytis cinerea) and five yeasts isolated from spoiled strawberry purée. Results aligned with literature data, identifying sorbic acid as the most effective inhibitor and lactic acid as the least across all strains.

The model, developed in synthetic strawberry medium (SSM), generally provided conservative or accurate predictions. Only 1 % and 10 % of observed growth values in SSM and strawberry purée, respectively, were faster than predictions (with a 20 % error margin). However, a biopreservation solution based on fermented vegetable juice had lower inhibitory activity than expected from its OA content, likely due to other compounds present. This suggests OA concentrations alone cannot predict biopreservation performance.

Identifying these additional compounds and understanding their actions could enhance model accuracy, incorporating matrix physicochemical properties.