Compositional dynamics of commercial black garlic during storage: Impact of aging conditions

Black garlic (BG) is a thermally processed garlic product with enhanced antioxidant properties. However, its compositional stability during post-aging storage remains insufficiently understood, particularly for commercially manufactured products with different processing histories. This study investigated storage-induced compositional changes in BG produced under three distinct industrial aging conditions during 90 days of refrigerated storage (4°C). Moisture, pH, fructose, total polyphenols, flavonoids, total thiosulfinate, S-allyl cysteine (SAC), and γ-glutamyl-S-allyl cysteine (γ-GSAC) were analyzed using multivariate statistical approaches. Moisture content increased significantly at 30 days (approximately 10-15%, p < 0.05) and stabilized thereafter, indicating internal water redistribution within the garlic matrix. Flavonoids decreased significantly (up to ∼40–50%, p < 0.05), whereas total polyphenols remained relatively stable. Sulfur-containing compounds exhibited dynamic transformations, with γ-GSAC decreasing progressively (approximately 30–40% at 90 days, p < 0.05) and SAC showing manufacturer-dependent fluctuations. Multivariate analysis identified moisture, flavonoids, fructose, and γ-GSAC as the major variables contributing to storage-dependent differentiation. The magnitude and trajectory of compositional changes differed among manufacturers, suggesting that initial aging conditions strongly influence storage stability. These findings indicate that post-aging storage is a chemically dynamic phase affecting the quality characteristics of commercial BG products.