Human Oral Phase Coupled with In Vitro Dynamic Gastrointestinal Digestion for Assessment of Plant Sterol Bioaccessibility from Wholemeal Rye Bread.

A dynamic gastrointestinal digestion system (simgi) after a human oral phase was used, for the first time, to assess the bioaccessibility of plant sterols (PS) from wholemeal rye bread (74.8 ± 2.2 mg of PS/100 g d.m.) and PS-enriched wholemeal rye bread (PS-WRB) (1.6 ± 0.04 g of PS/100 g of fresh bread). The use of these solid food matrices requires a novel adaptation of the gastric phase of the system. The PS identified in the breads are campesterol, campestanol, stigmasterol, ß-sitosterol, sitostanol, Δ5-avenasterol, Δ5,24-stigmastadienol, Δ7-stigmastenol, and Δ7-avenasterol. The bioaccessibility of the total PS, only quantifiable in PS-WRB, is 19.9%, with Δ7-avenasterol being the most bioaccessible and Δ5-avenasterol being the least (p < 0.05). As shown in this study, PS-WRB can be considered to be a good choice to include in the daily diet. Furthermore, although the use of dynamic digestion methods for evaluating bioaccessibility implies high costs and technical complexity, their application means a closer approximation to in vivo scenarios.

Anti-inflammatory activity of plant sterols in a co-culture model of intestinal inflammation: focus on food-matrix effect.

This study investigates the gut anti-inflammatory activity of a plant sterol (PS) food supplement (PS-FS), alongside PS-enriched milk-based fruit beverage and PS-enriched rye bread. A co-culture model based on a dual-chamber system with differentiated intestinal-like Caco-2 cells (apical) and RAW264.7 macrophages (basolateral) was used. The bioaccessible fractions (BF) of the samples were obtained after INFOGEST 2.0 simulated gastrointestinal digestion. The BF were added to the apical part (diluted 1/20 v/v with culture medium to avoid cytotoxicity) for 90 min, followed by stimulation with lipopolysaccharide (LPS) (1 µg mL-1, 24 h) on the basolateral side. The pharmacological interaction between samples and budesonide (1 µM, 90 min) was evaluated. Results indicate that PS-FS significantly attenuated LPS-induced secretion of IL-8 (28%) by Caco-2 cells, and TNF-α (9%) and IL-6 (54%) by RAW264.7 macrophages, whereas PS-enriched beverage and bread did not exhibit protective effects. Additionally, PS-FS demonstrated an improvement in oxidative status in Caco-2 cells, evidenced by reduced levels of reactive oxygen species (47%), iNOS protein expression (27%), and nitrite/nitrate secretion (27%). Mechanistically, PS-FS inhibited the NF-κB-COX-2-PGE2 signaling pathway in macrophages, resulting in decreased NF-κB p65 nuclear translocation (39%), COX-2 protein expression (32%), and PGE2 production (27%). Co-treatment with budesonide and PS-FS displayed an antagonistic effect (combination index 0.38-0.63). This study demonstrates the potent intestinal anti-inflammatory activity of a PS-FS, positioning it as a promising nutraceutical product for the management of inflammatory bowel diseases. However, the food matrix of the milk-based fruit beverage and rye bread appear to interfere with the anti-inflammatory activity of PS.

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.

Determination of cholesterol in human milk: an alternative to chromatographic methods / Determinación del colesterol en leche humana: una alternativa a los métodos cromatográficos

Introduction: human milk (HM) is considered the best option for feeding healthy infants. Cholesterol (CHOL) is important for proper development of the nervous system, and for hormone and vitamin synthesis in growing infants. Breastfeeding and dietary CHOL intake during infancy have been suggested to affect blood lipid levels and the risk of cardiovascular disease in adulthood. Gas chromatography is the technique most widely used to determine CHOL in HM. Chromatographic methods are specific for the determination of CHOL and other sterols present in HM, but are extremely time consuming, and the costs and equipment requirements mean that they are not accessible to all laboratories. Aim: the present study describes the optimization and validation of an enzymatic-spectrophotometric method for CHOL determination in mature HM. Method: determination of CHOL involves fat extraction with chloroform:methanol, hot saponification and extraction of the unsaponifiable fraction with diethyl ether. CHOL was determined by an enzymatic method in which the concentration of the lutidine dye formed is stoichiometric to the amount of CHOL, and is measured by the increase in light absorbance at 405 nm. Results: human milk fat (mg/mL) (27.5 ± 1.3) and CHOL (0.113 ± 0.004) in analyzed HM were within the ranges reported by others authors. Analytical parameters of the proposed method were assessed: The precision values (%) (expressed as the relative standard deviation (RSD)) were: 3.5 and 6.7 for intra- and inter-day, respectively. Accuracy, estimated by recovery assays, was 110 ± 1.6%. Conclusion: the validated enzymatic-spectrophotometric method for determining CHOL in HM constitutes an alternative for fast and simple analysis of CHOL with equipment requirements accessible to any laboratory (AU)

Introducción: la leche humana (HM) se considera el modo óptimo de alimentación en lactantes sanos. El colesterol (CHOL) es importante para el correcto desarrollo del sistema nervioso y la síntesis de hormonas y vitaminas en el crecimiento del lactante. Se ha constatado que la lactancia materna y la ingesta dietética de CHOL durante la infancia influye en los niveles de lípidos en sangre, así como en el riesgo de enfermedad cardiovascular en la edad adulta. La técnica más utilizada para determinar el CHOL en HM es la cromatografía de gases. Los métodos cromatográficos son específicos para la determinación del CHOL y otros esteroles presentes en la HM, pero el elevado tiempo consumido, los costes y la necesidad de una instrumentación específica hacen que no sea accesible para cualquier laboratorio. Objetivo: el presente estudio describe la optimización y validación de un método enzimático-espectrofotométrico para la determinación del CHOL en HM madura. Métodos: la determinación del CHOL requiere una extracción lipídica con cloroformo:metanol, saponificación en caliente y extracción del insaponificable con dietil éter. El CHOL fue determinado por un método enzimático en el que la concentración de lutidina formada es estequiométrica a la cantidad de CHOL, y se mide a 405 nm. Resultados: la cantidad de grasa (mg/mL) (27,5 ± 1,3) y de CHOL (0,113 ± 0,004) en la HM analizada se halla en el intervalo indicado por otros autores. Se evalúan parámetros analíticos del método propuesto: la precisión (expresada como desviación estándar relativa en %) fue de 3,5 y 6,7 para intra- e interdía, respectivamente. La exactitud, estimada mediante ensayos de recuperación, fue de 110 ± 1,6%. Conclusión: el método enzimático-espectrofotométrico validado para determinar el CHOL en HM constituye una alternativa para el análisis rápido y sencillo de CHOL empleando equipos accesibles para cualquier laboratorio (AU)