Sweet potato (Ipomoea batatas (L.) Lam.) is increasingly recognized as a functional crop due to its rich content of health-promoting phytochemicals. This study compared the phenolic compound profiles of four sweet potato varieties differing in flesh colour (purple, orange, white, and pale yellow) cultivated in three distinct regions of Hungary. The objective was to evaluate the relative effects of pigmentation and growing location on antioxidant capacity. Tubers were collected in triplicate and analyzed spectrophotometrically (UV–Vis) for vitamin C, total flavonoids, and total polyphenols. Statistical analysis using two-way ANOVA and Tukey’s HSD revealed that flesh colour had a significant effect on all antioxidant parameters (p < 0.05), whereas geographic origin did not. Purple-fleshed tubers exhibited markedly higher levels of vitamin C (21.6 mg/100 mL), flavonoids (378.7 mg/100 mL), and polyphenols (37.0 mg/100 mL) compared with the other colour groups. These findings indicate that pigmentation is a stronger determinant of antioxidant potential than cultivation region. The results highlight the promising nutritional value of Hungarian purple-fleshed sweet potato varieties, supporting their use in functional food development and sustainable agricultural diversification strategies.

Diallyl disulfide (DADS) and diallyl trisulfide (DATS) are major allicin-derived organosulfur compounds associated with biological activity and sensitivity to processing conditions. This study aimed to quantify DADS and DATS in commercial garlic products using gas chromatography–flame ionization detection (GC-FID) and to evaluate the effects of product formulation and processing on their concentrations. Fresh garlic, marinated garlic, garlic oil, tinctures, powders, dragees, and oil- and granulate-based capsules were analyzed. The GC-FID method showed excellent linearity for both analytes (R² = 0.9999). Marked differences were observed among the investigated product types, and selected pairwise comparisons indicated statistically significant differences (p < 0.05). Garlic oil contained the highest concentrations of both compounds, with mean DADS and DATS levels of 179.98 and 102.26 mg/g, respectively. In contrast, the mean concentrations in all other product groups were substantially lower, reaching 0.01068 mg/g for DADS and 0.03649 mg/g for DATS. Oil-based formulations showed markedly higher DADS concentrations than powder- and granulate-based products, whereas DATS was relatively more dominant in powder-based formulations. Marination and thermal processing were associated with reduced diallyl sulfide levels. These findings demonstrate that the investigated commercial garlic products differed substantially in their DADS and DATS content, mainly depending on formulation and processing. The pronounced variability observed among the investigated commercial products highlights the need for improved analytical standardization and quality control of garlic-based products.