Extraction of Starch From Corn Grits Using <i>Lactobacillus plantarum</i> and Acid Protease: Changes in Structure and Physicochemical Properties

ABSTRACT Starch extraction method using Lactobacillus plantarum and acid protease (AP) (from Aspergillus niger ) from corn grits was developed. To understand the effect of the lactic acid bacteria (LAB) and AP, the structure and physicochemical properties of extracted starches were compared to those from the extraction using NaHSO 3 (chemical extraction) or water. Compared to the chemical method, biological extraction resulted in a lesser increase in T o , T p , T c , and Δ H . Regarding pasting properties, both biological and chemical methods showed a reduction in peak viscosity and breakdown, alongside a significant rise in trough viscosity and final viscosity. Through analyzing the molecular structure of starch, the biological method resulted in a significant reduction in amylose content. Furthermore, the biological method exhibited a minor impact on the chain length distribution (CLD). For crystallinity, the biological methods showed significantly less improvement, which is corroborated with the results for the content of the double helix structure. Besides, the impact of the different methods on starch enzyme digestibility is minor. In summary, when compared to chemical and water extraction, the biological extraction (LAB + AP) exhibits a lesser influence on the overall properties of starch, rendering it a gentler extraction technique.