Heading 1903 covers starch that has been further processed into a specific physical form — pearls, flakes, grains, or similar shapes — for use as a food ingredient or thickener. Unprocessed or simply dried cassava starch that has not been shaped into these forms belongs in the chapter covering starches and inulin. The key criterion is whether the starch has undergone the shaping or agglomeration step.

Yes — tapioca pearls used in bubble tea are the classic example of the pearl form covered by heading 1903 and its single subheading 190300. Pre-cooked or flavored versions may warrant additional review if other ingredients are present in significant quantities, but plain starch-based pearls in their standard form fall squarely within this heading.