Impact of Fatty Acyl Composition and Quantity of Triglycerides on Bioaccessibility of Dietary Carotenoids

Abstract

A carotenoid-rich salad meal with varying amounts and types of triglycerides (TG) was digested using simulated gastric and small intestinal conditions. Xanthophylls (lutein and zeaxanthin) and carotenes (alpha-carotene, beta-carotene, and lycopene) in chyme and micelle fraction were quantified to determine digestive stability and efficiency of micellarization (bioaccessibility). Micellarization of lutein (+zeaxanthin) exceeded that of alpha- and beta-carotenes, which was greater than that of lycopene for all test conditions. Micellarization of carotenes, but not lutein (+zeaxanthin), was enhanced (P < 0.05) by addition of TG (2.5% v/w) to the meal and was dependent on fatty acyl chain length in structured TG (c18:1 > c8:0 > c4:0). The degree of unsaturation of c18 fatty acyl chains in TG added to the salad purée did not significantly alter the efficiency of micellarization of carotenoids. Relatively low amounts of triolein and canola oil (0.5-1%) were required for maximum micellarization of carotenes, but more oil (approximately 2.5%) was required when TG with medium chain saturated fatty acyl groups (e.g., trioctanoin and coconut oil) was added to the salad. Uptake of lutein and beta-carotene by Caco-2 cells also was examined by exposing cells to micelles generated during the simulated digestion of salad purée with either triolein or trioctanoin. Cell accumulation of beta-carotene was independent of fatty acyl composition of micelles, whereas lutein uptake was slightly, but significantly, increased from samples with digested triolein compared to trioctanoin. The results show that the in vitro transfer of alpha-carotene, beta-carotene, and lycopene from chyme to mixed micelles during digestion requires minimal (0.5-1%) lipid content in the meal and is affected by the length of fatty acyl chains but not the degree of unsaturation in TG. In contrast, fatty acyl chain length has limited if any impact on carotenoid uptake by small intestinal epithelial cells. These data suggest that the amount of TG in a typical meal does not limit the bioaccessibility of carotenoids.

Applicability of &lt;i&gt;in Vitro&lt;/i&gt; Models in Predicting the &lt;i&gt;in Vivo&lt;/i&gt; Bioavailability of Lycopene and &lt;i&gt;β&lt;/i&gt;-Carotene from Differently Processed Soups

“…Similarly, previous investigations of the efficiency of transfer of individual carotenoids from a food matrix to the aqueous or micellar fraction in response to in vitro digestion have shown that β-carotene is more readily micellarised than lycopene [29,30,35]. These findings therefore support the validity of in vitro models for comparisons of the relative bioavailability of different carotenes.…”

“…It is possible that the differences in uptake is related to structural changes during the storage of the soup, e.g. hydrolytic products of dietary lipids may modify physicochemical characteristics of the micelles [35]. The relative hydrophobicity of β-carotene and lycopene, their location and chemical form in the plant matrices, and their transfer between oil droplets and micelles are important, β-carotene in carrots are associated with proteins [36] surrounded by a thick membranous sheet and lycopene is present in the tomato as crystalloids that develop within or along thylakoid bodies [37].…”

Effects of Fats and Oils on the Bioaccessibility of Carotenoids and Vitamin E in Vegetables

“…between -carotene and lutein has been found in several studies. 9,12) Although there are few reports on the bioaccessibility of -tocopherol, Borel et al have reported that its bioaccessibility was highly variable between foods. They have found that lettuce and banana had high bioaccessibility, whereas nuts had low bioaccessibility.…”

“…9,12) However, the effects of the fatty acyl moiety of fats and oils, unsaponifiable matter, and other lipid classes on the bioaccessibility of carotenoids of diverse structures and y To whom correspondence should be addressed. …”

Nutrition, Brain Aging, and Neurodegeneration: Table 1.

“…Impor- tantly, the aged animals on walnuts also showed reduced microglial activity in the hippocampus. In addition to PUFAs, walnuts also contain other bioactive constituents which have been shown to influence brain function, including vitamin E, melatonin, and antioxidant polyphenols such as ellagic acid (Venkatachalam and Sathe, 2006) that could act synergistically with the PUFAs to increase dietary polyphenolic absorption and uptake following consumption (Huo et al, 2007).…”