Mechanochemical modification of Dioscorea spp. starch: exploring its nano-structural and functional properties for sustainable edible packaging

Abstract

The current study presents a sustainable mechanochemical method for synthesizing starch nanoparticles from underutilised yams Dioscorea bulbifera and Dioscorea esculenta. The starch nanoparticles were prepared via wet ball-milling (BM) of Dioscorea bulbifera starch (DBS) and Dioscorea esculenta starch (DES). The influence of mechanochemical alteration upon the structural and techno-functional attributes of DBS and DES was analyzed. SEM revealed that BM resulted in the fragmentation and surface roughening of DBS and DES. The FTIR and Raman spectra confirmed that the BM disintegrated DBS and DES, as evidenced by an increase in the intensity of the FTIR signal at 2932 cm⁻¹ and a decrease in the Raman band at 480 cm⁻¹. ¹³C NMR and XRD results showed that BM increased the amorphous nature of DBS and DES. BM significantly improved (p < 0.05) apparent amylose content, digestibility, oil absorption capacity, water absorption capacity, and significantly reduced (p < 0.05) gelatinization enthalpy of DBS and DES. Rheology evaluation showed that BM enhanced the viscoelasticity of DBS and DES. Collectively, these results demonstrate that BM altered the structural and techno-functional attributes of DBS and DES, thereby enabling them to be employed as fillers in sustainable edible packaging.