Malic acid gives a tart apple its sharp flavor, and as apples ripen it gradually breaks down. To track that decline precisely, a titrator adds reagent drop by drop to juiced samples until the reaction endpoint is reached — the exact amount of malic acid in each sample becomes measurable. Red Delicious apples stored at 4°C, 21°C, and 32°C are juiced at regular intervals, and the titrator measures how malic acid shifts across each temperature group. Starch levels get a parallel check with iodine spray. As storage temperature rises, both compounds decrease — and the longer the apples stay in storage, the steeper that decline.

Measuring vitamin C starts with adding drops of iodine to each sample until the color shifts — that endpoint marks exactly how much nutrient reacted. Here, the experiment applies that method to carrot cubes cooked by boiling and steaming at 15, 30, and 45 minutes. Each sample first receives sulfuric acid and starch solution, then iodine drop by drop. When the color changes, the test is done. Comparing all six samples shows which cooking method preserves the most vitamin C and how time behind the stove changes the result.