How can I control ice crystal size in home made pure juice lollies

With the recent hot weather we've been getting through so many Ice lollies (popsicles) that we have started making our own.

We are primarily using freshly squeezed orange juice (with bits *8') and freezing them in a frost free freezer regulated to -18°C.

Comparing them to the '100% juice' lollies we have been buying, they taste better but don't have quite the same texture when you bite into them.

In the commercial lollies, the ice crystals run in lines which radiate out from the central axis of each lolly. With our home frozen lollies, the ice crystals are randomly arranged in every orientation.

Answers to What stops commercial ice lollies from being rockhard? suggest changing the amount of sugar, or adding glycerin, pectin or gelatin.

I'm not sure whether adding more pectin would help, given that it's freshly squeezed orange juice that we're freezing, and the other suggestions aren't acceptable as we don't want to add any more sweeteners, and we want our lollies to be vegetarian, so no steak dipping^† here.

So, how do commercial freezers get this nice smooth, radiative arrangement of ice crystals without additives, and can I replicate this at home?

I presume that this is, in large part, a process control issue, with specific cooling profiles needed to get the ice crystals to form in a consistent way.

^{† Steak Dipping: What my partner calls the act of needlessly making something non-vegetarian by adding something for which there is a vegetarian alternative.}