LAUSR

Our aim was to incorporate olive leaf extract in both microencapsulated (ME) and nonencapsulated (NE) forms into tomato paste to get benefit from antimicrobial properties of the extract. Response variables were diametrical growth of Aspergillus flavus, total soluble solids (TSS), pH, and color indices of inoculated tomato paste. NE was more successful than ME to restrict growth of the fungus at both temperatures of 25 and 30 °C. Although the rate of TSS decreasing over the storage time was higher for ME samples than NE ones, but it remained constant for ME samples at the end of storage; TSS index of ME samples at 25 °C was kept unchanged for four final days of storage. Also, ME olive leaf extract could stabilize pH index equal to 4.75 (at 10th day of storage at 30 °C) for the rest of storage. ME samples enjoyed higher a* values than NE samples during storage at 30 °C. Considering fitting indices, Feed-Forward-Back-Propagation network, Levenberg–Marquardt training algorithm, hyperbolic tangent sigmoid transfer function with 3-5-6 and 3-6-6 topologies represented the best artificial neural network models to predict both physicochemical and microbial properties of ME and NE samples when inoculated by A. flavus, respectively. Practical applications Antimicrobial properties of herbs and spices have been recognized for several years. Natural herbs or spices tend to lose their efficiency and fail to release their beneficial effects evenly over a longtime period. Simultaneously, it has been proved that microencapsulation is able to build a barrier between components of particles and their environment. Thus, it might be applied for olive leaf extract to keep favorable properties of tomato paste. Our aim was to incorporate microencapsulated (ME) olive leaf extract into tomato paste to get benefit from antimicrobial properties of the extract (against Aspergillus flavus) over short and longtime storage. Also, our another objective was to model the physicochemical and fungal changes within tomato paste containing nonencapsulated and ME olive leaf extract for the first time.