Impact of fermentation with Lactobacillus plantarum and Saccharomyces cerevisiae on the acceptability of experimental breadsticks enriched with Ulva lactuca, and shelf-life study under tropical conditions

The use of macroalgae in baked goods represents an increasingly widespread fortification strategy. Ulva lactuca is an innovative ingredient of great interest due to its high mineral content. However, how it influences the stability of baked products during storage remains scarcely investigated. The present work aimed to evaluate the shelf-life under tropical conditions (38 °C and 90% RH) of experimental breadsticks enriched with 5% U. Lactuca (w/w in relation to flour), preceded by an assessment of a fermentative pre-treatment on the seaweed in order to optimize its sensory profile. Fermentative pre-treatment on the seaweed was carried out using Lactobacillus plantarum and Saccharomyces cerevisiae (in pure or mixed cultures for 24 and 48 h) and then the culture was incorporated into make experimental breadsticks. To investigate the effectiveness of this mitigation strategy on the “marine” aromatic profile, a consumer test was conducted. However, the results did not justify the implementation of the fermentation technology on a production scale from an applicative perspective, steering the shelf-life study towards the formulation made with unfermented seaweed. The effect on the antioxidant power and the determination of the free amino acid content of the breadsticks were also evaluated. The breadsticks were packaged in polypropylene bags (approximately 12 g each). Sampling occurred at 7-day intervals for physical analyses, including water activity (aW), moisture content, and colour parameters (CIELab space), alongside the evaluation of texture and aromatic profile performed by a trained panel. The shelf-life monitoring highlighted a progressive qualitative deterioration of the product, allowing the determination of a shelf-life of 28 days under the analyzed conditions. The results demonstrate that the storage limitations that emerged are mainly attributable to the reduced barrier properties of the packaging material when subjected to stressful environmental conditions.