Effect of potassium alum addition on the quality of potato starch noodles

The objective of this study was to investigate the effects and mechanism of potassium alum (PA) on potato starch noodles to provide a theoretical basis for future searches for new alternatives for PA that are not harmful to the body. The amount of amylose leakage significantly decreased with the PA addition. SEM showed that the honeycomb structure of potato starch noodles with 0.1% PA was diminished. The number of internal pores and average area decreased from 92 and 580.09 units to 72 and 652.58 units, respectively. NMR indicated that the water holding capacity of potato starch noodles containing PA was greater than that of the control. XRD showed that the crystal structure of potato starch noodles was destroyed and that the crystallinity of potato starch noodles with PA increased from 16.65 to 19.64%. G' and G'' increased, but tanδ decreased. FT-IR showed that PA caused the O-H stretching vibration in the absorption peak to move in the high-field direction and that the ionic bond was dominant in the PA-potato starch interaction system.

In vitro digestibility and quality attributes of white salted noodles supplemented with pullulanase-treated flour

This study aimed to develop a noodle with slow digestibility by adding pullulanase-treated wheat flour (PF). PF was prepared from normal wheat flour (NF) by pullulanase treatment, then its characteristics were compared with NF. Varying proportions (0%, 3%, 6%, 9%, 12% and 15%) of PF were substituted for NF to produce white salted noodles (WSN). The rheological, digestive, cooking, color and textural properties of WSN were evaluated. This showed that the amylose content of PF (83 wt%, total starch) was 62% higher than that of NF. After pullulanase treatment, the pasting temperature increased from 62.7 to 75.0 °C and the crystal structure of the starch changed from a mixture of A- and V-types to one of B- and V-types. Microstructure graphs showed that the structure of PF was more compact than that of NF. PF substitution produced noodles of acceptable quality with increased water absorption, cooking loss, L* value, hardness, and resilience and decreased cooking yield compared with the control (100% NF). In vitro digestibility tests showed that k (the kinetic constant) for cooked WSN decreased from 0.405 to 0.168 as substitution levels of PF increased from 0% to 15%, indicating that PF still exhibited slow digestibility after cooking.