## 4 Discussion  
Oat flour that underwent PEF treatment (different electric field strength and specific energy input levels) demonstrated variation in its starch digestibility properties. The amount of glucose released from hydrolysed starches in the sample correlates with the susceptibility of starch to digestive enzymes. Compared to Control, the increased levels of glucose released from PEF-treated oat flour at 421-438 kJ/kg during digestion suggests an increased susceptibility of starch to the action of enzymes (Figure 2). It is presumed that the modifications in the structural properties of starch in oat (e.g., deformation of starch granules, damage in the crystalline regions of starch), as a result of PEF treatment at elevated specific energy input, have improved its starch digestibility properties as demonstrated by a higher proportion of starch that is rapidly digestible (i.e., significant increase in RDS fraction) during _in vitro_ digestion (Table 1). On the other hand, lower levels of glucose released from digested samples (particularly those processed at increased electric field strength levels of 52-218 kJ/kg) indicate increased resistance of starch towards enzyme action. This finding was supported by both increment in the %RS and a considerable reduction in the rate of _in vitro_ starch digestibility, particularly for sample 4-B (Table 1). [PERSON] et al. [23] have outlined consistent reports that PEF treatment can improve starch digestibility with increasing electric field strength application. For example, [PERSON] et al. [14] reported that the application of higher electric field strength (30, 40, and 50 kV/cm) on waxy rice starch led to increased starch digestibility, which was expressed as increased levels of rapidly digestible starch. Similar observations were also reported by [PERSON] et al. [24] in studying the impact of increasing electric field strength application (2.86, 4.29, 5.71, 7.14, and 8.57 kV/cm) to wheat, potato, and pea starches. In this study, the potential to manipulate the susceptibility of starch to digestion was determined by varying the levels of PEF treatment intensity applied. Increased susceptibility of starch to digestion was associated with elevated specific energy input (421-438 kJ/kg) application while increased resistance of starch to digestion may be achieved with increased electric field strength application at 52-218 kJ/kg PEF treatment. Production of starch-rich foods with low GI has been a recent priority in the food industry in the context of health concerns against the risk of obesity and related diseases among population [25]. Findings from the present study clearly demonstrated the feasibility of PEF as a reliable technology, if applied at appropriate intensity, to maintain or even slow down the rate of starch digestion of starch-rich foods such as oats. By fractionating PEF-treated oat flour into three distinct flour segments, it was possible to identify that PEF treatment elicited varying levels of impact on a heterogenous material, that is oat flour. The uneven PEF treatment effect was evident in the changes observed in terms of particle size, damage and aggregation of starch granules, and destruction of the long- and short-range ordered structures of starch between the flour segments within a treatment (e.g., 2-A-SS1 vs. SS2 vs. SS3). Firstly, the greatest extent of modification (in terms of particle size, starch ordered structure and thermal properties) exhibited by SS1 samples from PEF-treated oat flour indicates that flour components that are most susceptible to property alteration, with PEF treatment application, are most likely to be found on SS1 or the topmost segment. On the other hand, the overall insignificant change in the morphology, gelatinisation enthalpy, and percent relative crystallinity of SS3 samples, even after PEF treatment at high specific energy input level of 421-438 kJ/kg, indicates that components of oat flour that exhibited resistance to the impact of PEF treatment are most likely to be found in SS3 or the bottom segment.