Fish Ambul Thiyal Goraka curing: hydroxycitric acid penetration and dry-simmering preservation?

Ambul Thiyal (sour dry fish curry) is a brilliant traditional preservation technique originating along the southern fishing coast. Dense cubes of fresh skipjack tuna (Balaya) are coated in a thick, concentrated black paste of ground sun-dried Goraka (Garcinia cambogia), black pepper, salt, and curry leaves. Goraka is extraordinarily rich in (-)-hydroxycitric acid (HCA), dropping the meat pH below 3.8. When simmered very slowly in a seasoned unglazed clay pot until all liquid evaporates, the acidic black paste penetrates every muscle fiber, denaturing bacterial enzymes and preserving the fish at room temperature for up to two weeks.