Gastric Emptying and Short-Term Digestibility of Thermally Oxidized Sunflower Oil Used for Frying in Fasted and Nonfasted Rats

Abstract

Four-hour in vivo digestibility of sunflower oil used in frying was tested in fasted and nonfasted rats. For three consecutive days, 12 male Wistar rats received 1 g of unused oil (controls, C), while 12 received 1 g of used oil (test group, T). On the night of day 3, 6 rats from each group were fasted (FC, FT) while the other 6 animals from each group had free access to food (NFC, NFT). On day 4, FC and NFC received 2 g of unused oil, while FT and NFT received 2 g of used oil. Luminal gastric and intestinal fats were studied by column and HPSE chromatography after endogenous corrections. Gastric emptying in FT was significantly slower than in NFT and FC. The luminal gastric fat profile differed from that of the oils administered, suggesting that nonoxidized triacylglycerols passed quickly into the intestines. All glyceridic compounds present in the luminal intestinal fat were affected by oil type (at least P < 0.01). Oil digestibility value order was FT < NFT < FC < NFC. FT and NFT presented lower (P < 0.001) triacylglycerol polymer and dimer digestibilities than NFC and FC. In conclusion, oil type determined luminal intestinal fat compounds and their digestibility more than nutritional status.

Possible adverse effects of frying with vegetable oils

“…Thus, linoleic acid hydroperoxides administered intragastrically was converted into hydroxyls, epoxyketones, hexanal and 9-oxononanoic acid, time-dependently (52,53) . Other authors have reported that gastrointestinal glutathione peroxidase plays an important role in the mucosal transport and in the conversion of hydroperoxides to more OH OH Lipase Márquez-Ruiz et al (18 -20) , Gonzá lez-Muñoz et al (21) and Olivero-David et al (22,23) Low lipolysis of TAG polymers Márquez-Ruiz et al (20) and González-Muñ oz et al (21) TAG polymers decrease lipolysis of non-modified TAG Márquez-Ruiz et al (20) and González-Muñ oz et al (21)…”

Can Meat and Meat-Products Induce Oxidative Stress?

“…Again, several different situations made this topic complex and difficult to study and clearly demand to avoid doing any generalization as iron content in meat is rather variables as we have discussed in Section 4 . In addition, the consumption of “red” meat is expected to induce more oxidation effects after a large interprandial period (e.g., 15 h) that after a shorter one (4–5 h) as the activity and expression of gastrointestinal antioxidant enzymes is highly modified by the fasting conditions [ 59 ].…”

Role of the food matrix and digestion on calculation of the actual energy content of food

“…Recently, it was reported that, in Wistar rats, the digestibility of thermally treated sunflower oil is up to 30% lower than that of fresh sunflower oil. 88 It is still unclear whether the reduced bioavailability of frying oils derives from the poor absorption of polar oxidation products or whether those oxidation products affect the catalytic activity of pancreatic lipase. The digestibility of lipids may also be altered by heating as a consequence of the physical damage of the original food structure.…”