Effects of spray freeze drying and pulsed electric fields on fenugreek seed extract properties

Butti Prabhakar, Raghupatruni Venkateswara Prasad

Abstract

Plant extracts are increasingly recognized for their potential health benefits, creating a growing demand for efficient extraction and preservation methods. In this study, a pulsed electric field (PEF) system was applied to maximize the extraction of plant bioactives, followed by encapsulation using spray freeze drying (SFD), a novel preservation technique. Among solvents tested, ethanol yielded the highest extract recovery (166.66 mg GAE/g), whereas methanol (sample-to-solvent ratio 1:10) resulted in the highest total polyphenol content. In the encapsulation process, gum acacia (GUA) at a 1:6 extract-to-binder ratio with a 30-hour lyophilization period produced powders with the lowest moisture content (3.9% w.b.), and SFD particles exhibited an average size of 9.0 μm. Furthermore, GUA as a binder and guar gum at a 20-hour lyophilization period achieved the highest polyphenol encapsulation efficiency. These findings highlight PEF-assisted extraction combined with SFD encapsulation as a cost-effective and efficient strategy for industrial-scale preservation of plant bioactives.

Keywords:

Pulsed electric field, spray freeze drying, encapsulation, gum acacia, plant extracts