Development of O/W Pickering Emulsions Stabilized with Leek Leaf Trimmings Using Batch and Continuous Modes

Abstract

Vegetable trimmings can be used to stabilize edible O/W Pickering emulsions. The lignocellulosic biomass (LCB) from the leek trimmings was mechanically treated to produce high-yield lignocellulose micro and nanofibrils (LCF) using a high-pressure homogenizer (HPH). Different O/W phase ratios (20/80, 30/70, and 40/60 wt.%) were studied. The use of the micro/nano cellulosic fibers increased the stabilization of the Pickering emulsions by 30–40%. In all cases, stable emulsions were obtained, with emulsification indexes > 92%. The respective stabilization mechanism was thoroughly analysed from confocal laser scanning, and cryo-scanning electron microscopy, which showed the fibers are not coating the droplets but forming a network that traps the droplets and prevents coalescence. The most stable batch formulations, O/W 30/70 wt.% (LCB 4.2 wt.%) and O/W 40/60 wt.% (LCB 3.6 wt.%), were also studied in continuous mode using NETmix technology. Results show the scale-up feasibility of the production of Pickering emulsions containing LCF. Most significantly, this work proposes a continuous process to produce Pickering emulsions stabilized with a natural biopolymer extracted from leek trimmings, which is suitable to industrial manufacturing processes. This valorizes the vegetable trimmings that are usually tossed away as waste, creating new market niches and business models based on circular economy concepts. Graphical Abstract