Repurposing Olive Oil Mill Wastewater into a Valuable Ingredient for Functional Bread Production

Area of Science:

• Food Science
• Food Chemistry
• Food Technology

Background:

• Olive oil mill wastewater (OOMW) is a significant byproduct of olive oil production, often posing environmental challenges.
• Valorizing OOMW into value-added food products presents an opportunity for sustainable practices and functional food development.

Purpose of the Study:

• To investigate the feasibility of incorporating untreated OOMW into bread production.
• To evaluate the impact of OOMW on dough fermentation, bread quality, chemical composition, and functional properties.
• To assess the potential of OOMW-enriched bread as a functional food product.

Main Methods:

• Two experimental breads were produced using 50% and 100% OOMW replacing water, with sourdough (S) and biga-like (B) inoculums.
• Dough acidification, microbial growth, and hygienic quality were monitored during fermentation.
• Bread quality parameters (weight loss, volume, color, texture) and chemical composition (volatile compounds, polyphenols) were analyzed post-baking.
• In vitro digestion and antioxidant capacity (Trolox equivalents) were assessed to determine functional properties.

Main Results:

• OOMW incorporation did not significantly alter yeast/LAB growth or dough acidification.
• Breads produced with OOMW and a biga-like inoculum (EXP_B) exhibited better specific volume and alveolation compared to sourdough (EXP_S).
• EXP_B breads showed increased levels of alcohols, carbonyls, esters, and terpenes, and contained beneficial phenolic compounds (hydroxytyrosol, coumaric acid, etc.).
• Antioxidant capacity significantly increased in OOMW-enriched breads (2.4- to 3.9-fold).
• No significant reduction in post-prandial hyperglycemia was observed due to similar starch digestibility.
• Sensory analysis indicated high appreciation for OOMW-enriched breads (EXP_B-1 and EXP_B-2) based on visual, structural, and olfactory attributes.

Conclusions:

• Untreated OOMW can be successfully incorporated into bread, particularly using a biga-like leavening process.
• OOMW enrichment enhances bread's antioxidant profile and sensory appeal without negatively impacting fermentation.
• Further research is needed to address starch digestibility and potential health benefits related to hyperglycemia.
• This study demonstrates a promising avenue for OOMW valorization into a functional food product.