Starch gelatinization, retrogradation and disgestability

Over on the sub-reddit on prebiotics we're a bit stumped on figuring out the process for turning raw potato starch (mainly containing R2 resistant starch) into R3 via retrogradation/gelatinization. The best thing we have found so far on the topic is [this article](https://koreauniv.pure.elsevier.com/en/publications/effect-of-partial-gelatinization-and-retrogradation-on-the-enzyma), which is quite a bit too technical for us (e.g. what's melting enthalpy?) and doesn't fully answer our questions.


I myself had a haphazard go at it, boiling water with potato starch for an extended period of time (sorry, don't have exact ratios or times) and then leaving it in the fridge for 3 days. The end result was large chunks of a milky-clear substance of soft-gummybear consistency (can be picked up and lightly squeezed without loosing form or oozing) that will not disolve in water. My personal question is: what is the substance described here and what's could be assumed its digestibility?


For the r/prebiotics reddit in general, the question is what process should be be used by a layman to turn raw potato starch powder into either gelatinized and or retrograded starch (assuming here they're different). I presume the variables we need are water/starch ratio, mixing technique, heating temperature, lenght of heating, cooling temperature and cooling time.


Thank you in advance and for your time.


