Structural modification and functional improvement of starch nanoparticles using vacuum cold plasma.

Starch nanoparticles (SNPs) have become one of the most interesting nanocarriers due to their relatively easy synthesis, biocompatibility, and biodegradability. However, the practical applications of SNPs are limited, as their aggregation reduce their functionality. Here, SNPs obtained by recrystallizing debranched waxy maize starch were modified using oxygen and ammonia vacuum cold plasma (CP). The modified SNPs were measured using Fourier transform infrared spectroscopy, showing a new carbonyl or carboxyl peak at 1720 cm-1. SNPs modified with oxygen CP treatment have negative charges (-21.6 to -15.1 mV). Modified SNPs with diameter ranging from 75.94 to 159.72 nm had good dispersibility without much aggregation. The relative crystallinity of modified SNPs decreased from 44.13% to 33.80%. Moreover, modified SNPs showed high absorption of tea polyphenols, indicating that as nanocarriers, they can accommodate more cargo molecules than primary SNPs. CP modification of SNPs is simple, green, and inexpensive. Modified SNPs can be used as nanocarriers to deliver drug or food components in the food and pharmaceuticals industries.