Microwave–Assisted OSA–Faba Bean Starch Production for Probiotic Microencapsulation

Abstract

Probiotics offer significant health benefits; however, their efficacy is often compromised by low survival rates in stressful conditions. Microencapsulation using modified starches presents a promising strategy to enhance probiotic viability. This study aimed to evaluate microwave-assisted octenyl succinic anhydride (OSA) modification of faba bean starch to provide a protective matrix for the microencapsulation of Lactobacillus rhamnosus GG (LGG) through spray drying. Starch was extracted from faba beans and hydrolyzed, and a factorial design was employed for OSA esterification (3% w/w) using a conventional microwave (30 or 60 s at power levels of 2 or 10). The starches were characterized, and the most effective treatment was selected for the microencapsulation of LGG, varying the inlet temperature (120 and 140 °C) and flow rate (7 and 12 mL/min) at 30% solids content. Microwaves significantly reduced the processing time for starch esterification. Microwave-assisted OSA modification produced starches with low viscosity (<0.015 Pa·s), high amylose and resistant starch content, and good solubility, making them suitable for probiotic encapsulation. The microencapsulation of LGG resulted in a powder yield of 41–55%, with particle sizes ranging from 5 to 20 µm and survival rates of 81–90%. This study presents an effective method of producing OSA-modified starch from faba beans using microwave energy, demonstrating strong potential for probiotic delivery applications.