Postprandial Antioxidative Response to Ingestion of Formulated Date- and Fruit-Based Nutritional Bars by Healthy Individuals

Nutritional bars (NBs) are gaining popularity among healthy and athletic individuals, but postprandial antioxidative response has not been investigated. Therefore, the current study examined the postprandial alterations in total phenolic content (TPC), total antioxidant capacity (T-AOC), malondialdehyde (MDA), and Superoxide dismutase (SOD) in the plasma of healthy individuals after the ingestion of 140 g (510 Kcal) from formulated date-based bars (DBBs) or fruit-based bars (FBBs). Firstly, the free and bound phenolic contents (PCs) were determined to be 10.15 and 12.98 and 6.19 and 3.57 mg GAE g-1, respectively. FBBs were significantly higher in free PC than DBBs, while DBBs were considerably higher in bound PC than FBBs. Secondly, twenty participants with age, height, weight, body mass index (BMI), fat mass, and fat-free mass averages of 21.4 years, 170.0 cm, 66.3 kg, 22.9 kg m2, 14.5, and 29.2 kg, respectively, were subjected to metabolic experiments (ISRCTN19386758). Ingestion of 140 g of FBB or DBB resulted in 288.50 or 302.14 µg TPC mL-1 blood, respectively. Postprandial TPC content increased with time progression and peaked after 120 min. T-AOC contents averaged 22.63 and 23.61 U mL-1 before ingestion of FBBs or DBBs, respectively. The T-AOC content increased significantly 120 and 180 min after ingestion of DBBs, while no significant change was noted after consuming FBBs. A significant decrease in MDA content was observed 180 min after consuming DBBs, while no significant change was noted after consuming FBBs. SOD concentrations ranged from 193.99 to 201.07 U L-1 in FBBs and DBBs, respectively. No considerable response was noted up to 3 h after ingestion of FBBs. On the contrary, a significant response was found 120 min after consuming DBBs. Pearson's correlation coefficient indicated a highly significant positive correlation coefficient (p < 0.01) between T-AOC and either MDA or SOD, as well as between MDA and SOD. The principal component analysis demonstrated a strong and positive relationship between SOD and TPC at 60 and 120 min after DBB ingestion. In conclusion, the relative changes in postprandial responses in T-AOC and MDA did not significantly (p > 0.05) differ between DBBs and FBBs, except for TPC (p = 0.04, paired t-test) and SOD (p = 0.003, paired t-test). Further studies with an extended experimental time are needed to confirm the current findings.