PAN ‐ AgNPs Nanofibrous Membrane‐Based Microfiltration for Sterilization of Tender Coconut Water: An Innovative Clean‐Label Preservation Approach

Tender coconut water (TCW) is a highly nutritious natural beverage. However, its commercial utilization is limited by rapid microbial spoilage and the adverse effects of conventional thermal preservation on its nutritional and sensory quality. In the present study, a non‐thermal sterile microfiltration approach was developed using electrospun polyacrylonitrile (PAN) and silver nanoparticle (AgNPs)‐incorporated PAN (PAN‐AgNPs) nanofibrous membranes for the clean‐label preservation of TCW. The fabricated membranes were comprehensively characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller (BET) analysis, water contact angle (WCA) measurements, membrane thickness, and inter‐fiber spacing analysis. Among the fabricated membranes, the 10 wt.% PAN‐AgNPs nanofibrous membrane exhibited superior microfiltration performance, achieving complete removal of both Escherichia coli ‐spiked and naturally occurring microorganisms while maintaining a high permeate flux and ease of cleaning. The membrane demonstrated favorable filtration characteristics with low irreversible fouling and excellent flux recovery, indicating its suitability for repeated operation. Ion chromatography (IC) confirmed that the natural mineral composition of TCW was largely preserved following microfiltration, whereas inductively coupled plasma mass spectrometry (ICP‐MS) detected no measurable silver migration into the permeate, confirming the stability and food‐contact safety of the incorporated AgNPs. The sterile microfiltered TCW remained microbiologically stable and sensorially acceptable for 120 days at ambient temperature (27°C ± 3°C) without thermal treatment or chemical preservatives. These findings demonstrate that electrospun PAN‐AgNPs nanofibrous membranes provide an effective, scalable, and clean‐label preservation strategy for extending the shelf life of TCW while retaining its nutritional and organoleptic quality. The developed membrane process also shows considerable potential for non‐thermal processing of other heat‐sensitive beverages and liquid foods.