The document summarizes a study that compared the ascorbic acid (vitamin C) content of different old Belgian apple cultivars and five commercial cultivars. The study found that the old apple cultivars contained three to seven times more ascorbic acid than the commercial cultivars. Factors like fruit diameter, maturity index, dry matter, and acidity influenced the ascorbic acid content. The study concluded that ascorbic acid content varied greatly between cultivars and sampling heterogeneity was an important factor to consider in apple research.