FATTY ACID PROFILE AND CHANGES IN BIOACTIVE COMPOUNDS OF Ipomoea batatas (L.) Lam LEAF FLOURS FROM LANDRACES AND CULTIVARS DURING SIMULATED GASTROINTESTINAL DIGESTION

Sweet potato leaves [Ipomoea batatas (L.) Lam, SPL] are promising sources of bioactive compounds, with significant genotypic variation. However, data on the stability of these constituents during gastrointestinal digestion, particularly in comparisons between landraces and cultivars, remain limited. Thus, this study aimed to characterize the fatty acid profile and evaluate genotype-dependent changes in the bioactive compounds of flours from four sweet potato leaf landraces (4, 92, 112, and 123) and two registered cultivars (“Maria Eduarda” – ME and “Maria Isabel” – MI) during in vitro gastrointestinal digestion. The landraces were donated by small-scale farmers and belong to the Sweet Potato Germplasm Bank at the Federal University of Paraná. The leaves were harvested at three months, sanitized, freeze-dried, and ground. Total lipid content was analyzed using the Soxhlet method, and the extracted lipids were transesterified into fatty acid methyl esters (FAMEs) and analyzed by GC-MS. Simulated gastrointestinal digestion followed the INFOGEST protocol. To monitor volatile and semi-volatile metabolites during simulated digestion, non-digested, gastric and intestinal phase fractions were freeze-dried and extracted with 80% methanol (0.01% HCl), dichloromethane, and ethyl acetate, and the resulting extracts were analyzed directly by GC-MS (without transesterification). The metabolites were identified by comparing their mass spectra with the NIST library. The total lipid content ranged from 3.88 to 4.94 g/100 g among the flours. All samples showed a predominance of polyunsaturated fatty acids, particularly α-linolenic acid (ω-3, 50.9%–66.3% of total FAMES) and linoleic acid (ω-6, 6.7%–11.5%). Palmitic acid was the main saturated fatty acid (19.9%–30.1%). Landrace 123 stood out for having a higher relative proportion of ω-3 and a lower proportion of saturated fatty acids. During simulated digestion, ω-3, ω-6, and palmitic acids were detected in all phases of the samples, while oleic acid was identified in all phases of landrace 123. Other bioactive compounds also showed genotype-dependent profiles: quinic acid was detected in all phases of landraces 4 and 123 and in both cultivars; phytol, in the gastric phases of 4 and 112 and in the intestinal phase of 92; squalene, in both gastric and intestinal phases of 92 and in the intestinal phase of 112; and the sesquiterpenes caryophyllene and germacrene D, exclusively in the intestinal phase of 112. These patterns likely reflect the release of compounds from the plant matrix, biotransformations during in vitro digestion, or a combination of both. These findings indicate genotype-dependent changes in the chemical profile of SPL before and during simulated digestion, highlighting landraces and cultivars as complementary sources of bioactive compounds for applications in functional foods.

Financial support and acknowledgment: CAPES.