Doesn’t look like the attachments came through…
Are you saying that the white background looks bad even in Lightroom, or only after exporting? I’m guessing the problem is that your background isn’t “true” white. Take a look at your histogram in Lightroom, that should show the truth of the matter. An easy way to test that is to move your “Whites” slider in Lightroom to the right until your background is completely blown out, even if it makes the picture look funny. Now export it and see if you’re still seeing the “ripples”. I’ve done very little with pure white backgrounds, but the I did do a few product shots of a lens, and to get the background to be “pure white” I took an adjustment brush and pushed the “Exposure” slider option all the way to the right, then painted around all over the background that was supposed to be white. While you’re in “Adjustment Brush” mode, you can hit the “O” key to show a red overlay which will show where all you’ve painted. That makes it easy to visualize some spots you’ve missed. If your photos are all basically the same, you can copy the brush across with the “Sync” tool so you don’t have to do it for each individual picture.
The “ripple” effect is greatly worsened by compression. The more a jpg file is compressed, the more visible the artifacts will become. If you would export as a lossles .tif it would probably decrease the problem. However, .tif files can easily be 5-6 times larger than .jpg, so unless you really need lossless, you’re better off with .jpg to save on hard drive space.