Effect of twin-xuscrew extrusion combined with cold plasma on multi-scale structure, physicochemical properties, and digestibility of potato starches

The influence of twin-screw extrusion (TSE), cold plasma (CP, 1, 5, and 9 min), and their combination (TSE-CP) treatment on the structural, physicochemical, rheological, solubility, and in vitro digestive properties of potato starches were studied. The results showed that CP slightly changed the starch granules morphology, maintained the growth ring and crystalline structure, promoted depolymerization of the amylopectin branch chain, and increased crystallinity and the ΔH value. It is worth noting that the resistant starch content increased from 84.80 to 86.46% in the short time CP modified potato starch. Meanwhile, TSE and TSE-CP treatments influenced surface morphology, growth ring of potato starch significantly. However, the dually modified potato starch using combined TSE and CP treatments promoted depolymerization of longer chains, increased the proportion of shorter chains and solubility, and improved the degree of hydrolysis. Furthermore, the single and dual treatments did not change the FT-IR spectra pattern. This study suggests that the combination between TSE and CP had more profound modification than the single treatment. The TSE combined with CP is an eco-friendly, thermal, and non-thermal combination technology, which can improve the multi-scale structure of starch and enhance physicochemical properties. Also, the dual treatment can be used to produce modified starch for industrial applications.