Phytosterols In Foods Research Articles

Human intestinal Caco-2 cell model to evaluate the absorption of 7-ketophytosterols and their effects on cholesterol transport

7-Ketophytosterols are the major oxidation products of phytosterols in foods, which have been associated with atherosclerosis. However, their absorption mechanism remains unclear. The aim of our work was to investigate the absorption mechanism of 7-ketophytosterols and their effects on the cholesterol transport using Caco-2 cell model. The absorption percentage of 7-ketositosterol and 7-ketocampesterol was 1.16 %−1.68 % and 1.18 %−2.23 % respectively in the Caco-2 model, which is higher than that of their parent phytosterols, but lower than cholesterol-d7. The apparent permeability of 7-ketositosterol and 7-ketocampesterol at 30 μmol/L in the basolateral (BL)-to-apical (AP) direction were 0.42- and 0.55-fold of that in the AP-to-BL direction, indicating an active intake in the permeation mechanism of 7-ketophytosterols. Ezetimibe could significantly inhibit the transport of 7-ketophytosterols (P < 0.05), which means that their transport depends on niemann-pick c1-like 1 (NPC1L1) protein. The transport of cholesterol-d7 was significantly inhibited by 7-ketophytosterols (P < 0.05). Taken together, this study deepened our understanding of the absorption mechanism of common food-born 7-ketophytosterols and provides useful information on the inhibition of 7-ketophytosterols absorption.

Novel encapsulation approaches for phytosterols and their importance in food products: A review

AbstractPhytosterols are naturally occurring plant cell membranes, which have received greater attention in food industries due to their potential health benefits especially lowering low‐density lipoprotein (LDL) cholesterol levels within the human body. However, the application of phytosterols in various foods (aqueous‐based) is challenging due to their low water solubility and poor stability resulting in poor bioavailability/bioaccessibility. The encapsulation technique is considered as an alternative approach to protect phytosterols from various factors, thus improving their bioavailability and stability. This review aims in presenting a detailed study on techniques and technologies currently employed to encapsulate phytosterols. Based on recent studies, mostly used techniques are spray drying, freeze drying, spray chilling, emulsification, liposome entrapment, extrusion, electro‐spinning, and electro‐spraying. Various processing factors affecting phytosterol stability in fortified food have been outlined as well.Practical ApplicationsPhytosterols are plant‐based bioactive compounds that have been commonly linked to having anti‐diabetic, anti‐inflammatory properties and cholesterol‐lowering effects. Consumption of processed and ready‐to‐eat foods lowers the intake of plant sterols in the human diet. Additionally, their availability in plant‐based foods is also limited. Phytosterol fortified foods are now available to fulfill the phytosterol requirement in our diet. The consumption of phytosterol enriched foods or supplements can be an alternative option to lower cholesterol levels in the human body. However, phytosterols are insoluble in water which results in poor bioavailability and stability. Furthermore, the incorporation of phytosterols in food products is difficult due to the probability of oxidation at higher processing temperatures and storage. Hence, encapsulation is an alternative approach to enhance phytosterols' stability and bioavailability.

Simultaneous analysis of free phytosterols and phytosterol glycosides in rice bran by SPE/GC–MS

In this study, free phytosterols and phytosterol glycosides in rice bran were successfully separated and analyzed using solid-phase extraction (SPE) combined with gas chromatography–mass spectrometry (GC–MS). The results showed that free phytosterols in rice bran included ergosterol (129 ± 8 μg/g rice bran), campesterol (126 ± 9 μg/g rice bran), stigmasterol (106 ± 9 μg/g rice bran), β-sitosterol (305 ± 10 μg/g rice bran), cycloartenol (80.5 ± 3.9 μg/g rice bran) and 24-methylenecycloartenol (87.1 ± 2.2 μg/g rice bran), while phytosterol glycosides included campesterol glucoside (16.0 ± 1.3 μg/g rice bran), stigmasterol glucoside (99.0 ± 4.9 μg/g rice bran) and β-sitosterol glucoside (133 ± 7 μg/g rice bran). The methodological validation indicated that this method could accurately quantify free phytosterols and phytosterol glycosides in rice bran. This study provided a new direction to establish a rapid and simple method for the simultaneous determination of different forms of phytosterols in foods.

The preparation of phytosteryl succinyl sucrose esters and improvement of their water solubility and emulsifying properties

Phytosterols have gained much attention due to their outstanding cholesterol-reducing effect, while the insolubility in water limits their application. The aim of this study was to synthesize a novel hydrophilic phytosteryl derivatives-phytosteryl succinyl sucrose esters (PSSEs) and investigated their water solubility and emulsifying properties. PSSEs were synthesized by esterifying phytosterol hemisuccinates with sucrose through a mild chemical reaction. PSSEs were characterized by fourier transform infrared spectroscopy, mass spectroscopy, and nuclear magnetic resonance spectroscopy. The yield of PSSEs exceeded 84% in N,N-dimethylformamide for 36 h of reaction under the selected conditions: 100 mmol/L phytosteryl hemisuccinates, 150 mmol/L sucrose, 110 mmol/L 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochlide, 10 mmol/L 4-dimethylaminopyridine and 10 mmol/L p-toluenesulfonic acid. The water insolubility of phytosterols was overcome and the water solubility of PSSEs achieved 2.13 mg/mL. The emulsifying activity of PSSEs was 2.5 times that of phytosterols, reaching 0.95 mg/mL. PSSEs with better water solubility and emulsification properties could facilitate the widespread use of phytosterols in foods.

Thermo-Oxidation of Phytosterol Molecules in Rapeseed Oil during Heating: The Impact of Unsaturation Level of the Oil.

Phytosterols are naturally occurring substances in foods of plant origin that have positive effects on the human body. Their consumption can reduce the level of low density lipoprotein (LDL) cholesterol. The presence of unsaturated bonds in their structure leads to their oxidation during production, storage, and thermal processes. The aim of the study was to determine how the degree of unsaturation of rapeseed oil affects the oxidation of phytosterols in oil during 48 h of heating. In all not-heated oils, the dominant groups of oxyphytosterols were 7α- and 7β-hydroxy sterols. During 48 h of heating, the rapid decrease of phytosterols’ levels and the increase of the content of oxyphytosterols were observed. The main dominant group in heated samples was hydroxy and epoxy sterols. Despite differences in fatty acid composition and content and composition of single phytosterols in unheated oils samples, the total content of oxyphytosterols after finishing of heating was on a similar level for each of the tested oils. This showed that the fatty acid composition of oil is not the only factor that affects the oxidation of phytosterols in foods during heating.

Phytosterol oxidation products (POP) in foods with added phytosterols and estimation of their daily intake: A literature review.

1To evaluate the content of phytosterol oxidation products (POP) of foods with added phytosterols, in total 14 studies measuring POP contents of foods with added phytosterols were systematically reviewed. In non‐heated or stored foods, POP contents were low, ranging from (medians) 0.03–3.6 mg/100 g with corresponding oxidation rates of phytosterols (ORP) of 0.03–0.06%. In fat‐based foods with 8% of added free plant sterols (FPS), plant sterol esters (PSE) or plant stanol esters (PAE) pan‐fried at 160–200°C for 5–10 min, median POP contents were 72.0, 38.1, and 4.9 mg/100 g, respectively, with a median ORP of 0.90, 0.48, and 0.06%. Hence resistance to thermal oxidation was in the order of PAE > PSE > FPS. POP formation was highest in enriched butter followed by margarine and rapeseed oil. In margarines with 7.5–10.5% added PSE oven‐heated at 140–200°C for 5–30 min, median POP content was 0.3 mg/100 g. Further heating under same temperature conditions but for 60–120 min markedly increased POP formation to 384.3 mg/100 g. Estimated daily upper POP intake was 47.7 mg/d (equivalent to 0.69 mg/kg BW/d) for foods with added PSE and 78.3 mg/d (equivalent to 1.12 mg/kg BW/d) for foods with added FPS as calculated by multiplying the advised upper daily phytosterol intake of 3 g/d with the 90% quantile values of ORP. In conclusion, heating temperature and time, chemical form of phytosterols added and the food matrix are determinants of POP formation in foods with added phytosterols, leading to an increase in POP contents. Practical applications: Phytosterol oxidation products (POP) are formed in foods containing phytosterols especially when exposed to heat treatment. This review summarising POP contents in foods with added phytosterols in their free and esterified forms reveals that heating temperature and time, the chemical form of phytosterols added and the food matrix itself are determinants of POP formation with heating temperature and time having the biggest impact. The estimated upper daily intakes of POP is 78.3 mg/d for fat‐based products with added free plant sterols and 47.7 mg/d for fat‐based products with added plant sterol esters. Phytosterols in foods are susceptible to oxidation to form phytosterol oxidation products (POP). This review summarizes literature data regarding POP contents of foods with added phytosterols that were exposed to storage and heat treatments.

Determination of cholesterol and four phytosterols in foods without derivatization by gas chromatography-tandem mass spectrometry

In this study, a method for determination of cholesterol and four phytosterols by gas chromatography coupled with electron impact ionization mode–tandem mass spectrometry without derivatization in general food was developed. The sample was saponified with 7.5% KOH in methanol. After heating on hot plate and reflux for 60 minutes, the saponified portion was extracted with n-hexane/petroleum ether (50:50, v/v). The extracts were evaporated with rotary evaporator and then redissolved with tetrahydrofuran. The tetrahydrofuran layer was transferred into an injection vial and analyzed by gas chromatography on a 30 m VF-5 column. Limit of quantification was 2 mg/kg. Recoveries of cholesterol and four phytosterols from general food were between 91% and 100%.

The Role of Phytosterols Enriched Foods-A Review

Phytosterols exist as naturally occurring plant sterols that are present in the nonsaponifiable fraction of plant oils. Phytosterols (plant sterols and stanols) are well known for their low density lipoprotein- cholesterol (LDL-C)-lowering effect. Although many studies have been conducted to resolve the mechanisms of action by which phytosterols lower serum cholesterol. Dietary Phytosterols appear to play an important role in the regulation of oxidation and serum lipids and exhibit anticancer properties. However, as the study confines to the effect of phytosterol on lipid regulation, the review is confined to phytosterol and their role in control of cardiovascular disease (CVD). The information reviewed is presented under the following sections as types of Phytosterols and their structures, mechanism of action, phytosterols in foods for cvd risk reduction, phytosterols as ingredient in functional foods, stability of phytosterols in foods, safety aspects and regulatory status of phytosterols, phytosterols content in foods and phytosterol enriched products are reviewed.

Développements analytiques pour l’évaluation de la teneur en phytostérols des aliments : approche inter-laboratoires

A set of collaborative studies was carried out on 6 food items in order to determine their contents phytosterols. The interest of these studies is to make it possible to calculate a certain number of figures of merit for methods known as of reference methods. Finally, the calculation of the function of uncertainty for these methods shows that uncertainty remains high, especially for the weak concentrations, and that it must have a substantial influence on the evaluation of phytostérols intake. Similarly, it can be concluded that the analysis of phytosterols in foods remains a delicate operation which would deserve more attention from standardization bodies, especially in the current context of supplementation of certain foods.

Separation of Δ5- and Δ7-Phytosterols by Adsorption Chromatography and Semipreparative Reversed Phase High-Performance Liquid Chromatography for Quantitative Analysis of Phytosterols in Foods

A method for the separation, isolation, and identification of phytosterols was developed. A commercial phytosterols mixture, Generol 95S, was fractionated first by adsorption silica gel column chromatography and then separated by means of a semipreparative reverse phase high-performance liquid chromatography fitted with a Polaris C8-A column (250 mm x 10 mm i.d., 5 microm) using isocratic acetonitrile:2-propanol:water (2:1:1, v/v/v) as the mobile phase. Milligram scales of six individual phytosterols, including citrostadienol, campesterol, beta-sitosterol, Delta7-avenasterol, Delta7-campesterol, and Delta7-sitosterol, were obtained. Purities of these isolated sterols were 85-98%. Relative response factors (RRF) of these phytosterols were calculated against cholestanol as an authentic commercial standard. These RRF values were used to quantify by gas chromatography-mass spectrometry (GC-MS) the phytosterols content in a reference material, oils, and chocolates.