Lipolysis and Sterol Stability and Bioaccessibility of Wholemeal Rye Bread Enriched with Plant Sterols Subjected to Adult and Elderly Digestion Conditions.

This study evaluated the impact of different digestion conditions (adult and senior) on lipolysis and bioaccessibility of plant sterols (PS) and phytosterol oxidation products (POPs) in PS-enriched wholemeal rye bread. Under adult digestion conditions, the addition of gastric lipase (GL) reduced lipolysis products (by 6.1% for free fatty acids and 11.7% for monoacylglycerols) and the bioaccessibility of PS by 6.7%, compared to the control. In digestion with both GL and cholesterol esterase (CE), these reductions were 12.9, 20.1, and 11.3%, respectively. Both modifications (GL and GL + CE) increased the bioaccessibility of POPs by 4.5-4.0%. When simulating the elderly digestion, the modified gastric and intestinal phases did not alter PS bioaccessibility but decreased POPs bioaccessibility by 21.8% compared to control, along with reduced lipolysis. Incorporating GL and CE thus approached physiological conditions and influenced lipid digestion. Elderly simulated digestion conditions resulted in a positive outcome by maintaining PS bioaccessibility while reducing potentially harmful POPs.

Influence of Galactooligosaccharides on the Positive Effect of Plant Sterol-Enriched Beverages on Cardiovascular Risk and Sterol Colon Metabolism.

In the present study, the impact of galactooligosaccharide (GOS) addition to a plant sterol (PS)-enriched beverage on the hypocholesterolemic effect and on the bioavailability and colonic metabolization of sterols was evaluated. A crossover trial was undertaken in postmenopausal women who intook a PS-enriched (2 g PS/day) or PS-GOS-enriched beverage (2 g PS/day and 4.3 g GOS/day) for 6 weeks. The presence of GOS did not modify the hypocholesterolemic effect of the PS-enriched beverage (total- and low-density lipoprotein-cholesterol reductions) or sterol bioavailability (increments of serum markers of dietary PS intake and of cholesterol synthesis). The consumption of both beverages led to an increase of sterol and metabolite excretion (with the exception of coprostanol, which decreased) and to slight changes in women's capacities for sterol conversion, regardless of the GOS presence. This study demonstrates the suitability of simultaneous enrichment with PS and GOS in milk-based fruit beverages, considering their hypocholesterolemic effect.

Impact of a Plant Sterol- and Galactooligosaccharide-Enriched Beverage on Colonic Metabolism and Gut Microbiota Composition Using an In Vitro Dynamic Model.

A beverage enriched with plant sterols (1 g/100 mL) and galactooligosaccharides (1.8 g/100 mL) was subjected to a dynamic gastrointestinal and colonic fermentation process to evaluate the effect on sterol metabolism, organic acid production, and microbiota composition. Production of sterol metabolites (coprostanol, methylcoprostanol, ethylcoprostenol, ethylcoprostanol, and sitostenone) was observed in the transverse colon (TC) and descending colon (DC) vessels in general, from 24 and 48 h, respectively. Microbial activity was assessed through the production of organic acids, mainly acetate in all colon vessels, lactate in the AC, and butyrate and propionate in the TC and DC. A higher diversity in the microbial community was found in the TC and DC, in accordance with a higher sterol metabolism and organic acid production. Although the prebiotic effect of galactooligosaccharides was not detected, changes in microbiota composition (an increase in the Parabacteroides genus and the Synergistaceae and Lachnospiraceae families) indicated an enhancement of sterol metabolism.

A positive impact on the serum lipid profile and cytokines after the consumption of a plant sterol-enriched beverage with a milk fat globule membrane: a clinical study.

The hypocholesterolemic effect and the modification of serum biomarkers of a dietary plant sterol (PS) intake, cholesterol precursors and cytokines after the consumption of milk-based fruit beverages with a milk fat globule membrane were evaluated by a randomized, double-blind, crossover, multiple dose bioavailability study. Postmenopausal women (n = 38) consumed daily 250 mL of a beverage with or without 2 g of PS added during 6 weeks in each of the study periods. With the intake of the PS-added beverage, significant decreases (mg dL-1) in serum total cholesterol (pre-treatment: 220.0 ± 27.8 vs. post-treatment: 212.9 ± 25.8; p < 0.05) and LDL-cholesterol (129.4 ± 28.5 vs. 121.7 ± 24.4; p < 0.05) were detected. The cholesterol precursor lathosterol (11.2%), markers of the dietary PS intake (campesterol 43.1% and ß-sitosterol 32.5%), and anti-inflammatory IL-10 cytokine (22.5%) increased significantly, with a concomitant significant reduction in pro-inflammatory IL-1ß (6.7%). No variations in HDL-cholesterol, other sterols (desmosterol and stigmasterol) or cytokines (IL-6, IL-8, IL-12p70 and TNF-α) were detected. These results indicated that this kind of PS-enriched milk-based fruit beverage is suitable during the period of clinical intervention, and its consumption may be an adequate way to improve PS functionality since a significant reduction in cholesterol levels has been observed. Therefore, the intake of this beverage could contribute to reduce the risk of cardiovascular disease also obtaining a beneficial effect on the serum inflammatory status in postmenopausal women.

The impact of galactooligosaccharides on the bioaccessibility of sterols in a plant sterol-enriched beverage: adaptation of the harmonized INFOGEST digestion method.

The effect of the addition of galactooligosaccharides (GOS) on sterol bioaccessibility in three plant sterol (PS)-enriched milk-based fruit beverages (without GOS addition (MfB) and with 2.5 g (MfB-G2) and 5.0 g (MfB-G5) GOS per 250 mL) was evaluated after micellar gastrointestinal digestion. Cholesterol bioaccessibility was very similar among beverages, though a slight significant increase (from 80% to 85%) was observed by the addition of 5.0 g GOS. The addition of GOS did not affect total PS bioaccessibility (≈37%). Based on the results obtained after micellar digestion, it has been demonstrated that these beverages could be a suitable food matrix for simultaneous enrichment with PS and GOS. The harmonized in vitro digestion model INFOGEST was applied to the MfB beverage, but the cholesterol content could not be quantified due to its contribution of bile salts. Hence, it was proposed: (i) a change in porcine bile salt concentration from 10 mM to 1.4 mM (in order to compare with micellar digestion); or (ii) a change of bile salt origin (bovine instead of porcine), maintaining physiological concentration (10 mM, INFOGEST condition). Both options allowed cholesterol quantification, with bioaccessibilities of 62% (reduction of bile salts) and 38% (replacement of the bile salt source), whereas plant sterol bioaccessibilities were 22% and 14%, respectively. Therefore, the change of bile salt origin maintaining INFOGEST concentration is proposed as a method to evaluate sterol (cholesterol and PS) bioaccessibility in these beverages, demonstrating the need for the selection of appropriate conditions of the INFOGEST harmonized method according to the food matrix and compounds to be determined.