Valorization of avocado (cv. Hass) waste powder in industrial-scale sourdough “ciabatta” bread production: Impact on microbial dynamics, quality attributes, and phenolic bioaccessibility

Abstract

This study investigates the incorporation of avocado waste powder (AWP), derived from peel, seeds, and discarded Hass avocados, into traditional Sicilian ciabatta bread to enhance its functional properties and promote sustainable food innovation. AWP was added at 5% and 10% levels (AWP5, AWP10), and sourdough fermentation was conducted using Fructilactobacillus sanfranciscensis, Weissella cibaria, and Leuconostoc citreum. Despite the initial microbial diversity in raw ingredients, fermentation effectively selected beneficial lactic acid bacteria, with AWP addition potentially supporting their growth. Technological parameters such as weight loss, volume, and firmness remained unaffected, while AWP significantly influenced crumb structure and color. Sensory analysis revealed a different color intensity, aroma, and taste persistency in AWP added breads, though higher AWP levels introduced off-notes. Volatile organic compound profiling showed increased terpenes and sesquiterpenes in AWP breads, enhancing aromatic complexity. Phenolic compound content was determined before and after in vitro digestion (INFOGEST protocol) in fortified breads. A significant increase in phenolic content with the incorporation of AWP compared to CTR bread was observed, with further enhancement after in vitro digestion. Higher bioaccessible polyphenols, particularly in AWP10 were catechin, gallic acid, and ellagic acid. These findings highlight ciabatta bread as a promising vehicle for functional ingredients, supporting circular economy principles and the valorization of agro-industrial by-products, while maintaining or improving key quality traits.