High Contents Of Phytosterols Research Articles

Effect of pretreatment with microwaves on oxidative stability and nutraceuticals content of oil from rapeseed

Demand for oil extracted by cold press, such as rapeseed oil, is increasing, but oil extraction yield, and nutraceuticals content are lower for cold pressed oil, compared with oil extracted by solvent. In this study, rapeseed was treated with microwaves, to investigate the possibility of enhancing oil extraction yield, oxidative stability and nutraceuticals content. Rapeseed was pretreated with microwaves for two different times (2 min and 4 min) and oil was then extracted with a press. To compare the results, oil was also extracted from untreated rapeseed by solvent and press. Results showed that solvent-extracted oil had the highest phytosterol content. Microwave pretreatment of rapeseed can increase the oil extraction yield (by 10%), phytosterols (by 15%) and tocopherols (by 55%) of the oil extracted by press. Oil extracted from untreated rapeseed by press had the lowest oxidative stability (1 h); this was increased to 8 h by pretreatment of rapeseed with microwaves. Therefore, from the obtained results, it is advisable to treat rapeseed with microwaves before extraction by oil press, because it gives a relatively good recovery of oil, with a high amount of nutraceuticals, and can produce oil with a longer shelf life and enhanced value.

Chemical Composition and Oxidative Stability of Selected Plant Oils

AbstractScientific data on the oxidative stability of borage oil, Camelina sativa oil, linseed oil, evening primrose oil and pumpkin seed oil are scarce. Chemiluminescence (CL) methods most commonly used to determine the oxidative stability of oils include measurement of hydroperoxide, intensity of light emitted during the accelerated oxidation process performed at high (>100 °C) temperatures or assisted by forced flow of air/oxygen through the sample. The aim of this study was to investigate the chemical composition and oxidative stability of selected vegetable oils available on the Polish market. Oxidative stability was determined using a fast, novel chemiluminescence‐based method, in which light emitted during oxidation process conducted at 70 °C in the presence of some catalyzing Fe2+ ions is measured. A reaction of the applied type has not been reported so far. High contents of tocopherols and phytosterols were found in the analyzed oil samples. Oxidative stability of the samples was in most cases higher than the stability of refined rapeseed oil, a relatively stable substance from the oxidation point of view.

SOME FACTORS INFLUENCING FREE STEROLS CONTENT IN BROCCOLI (BRASSICA OLERACEA L. VAR. BOTRYTIS ITALICA PLENCK.)

The aim of this study was to determine free sterol accumulation in edible parts of broccoli cultivars of different vegetation periods, in relation to a part of the plant and growing term. Broccoli cvs. “Chevalier” F1, “Marathon” F1 and “Cezar” were cultivated as a spring, summer or autumn crop. Sterol compounds were determined by high-performance liquid chromatography in the top part (florets) and in the lower part (stems) of broccoli. The florets contained higher amount of sterols than the stems. The dominant sterol, both in florets and stems, were β-sitosterol and brassicasterol, but sterol content differed between the cultivars. Total amount of free sterols in florets reached 230 mg/100 g dw. “Chevalier” was the cultivar of the highest content of sterols in florets and “Cezar,” of the lowest. The concentration of sterols differed for the terms of growing and was the lowest for the spring term. Sterol content changed during florets development and was the lowest at the nonmature stage of the broccoli. Cooking of broccoli increased free sterol content in fresh and dry weights of the edible part. PRACTICAL APPLICATIONS Many authors point out that consumption of broccoli positively influences the health condition of humans. There are data showing high phytosterol content in this vegetable. Phytosterols are very valuable components of the human diet due to high biological activity of these phytochemicals. In this study, the differentiation in free phytosterol accumulation between some standard cultivars of broccoli is shown. The differentiation in free phytosterol concentration in various sections of the edible part of broccoli, as well as the differentiation resulting from the plants' development, was also found as important to a potential consumer.

품종별 포도씨의 식물성 스테롤 및 지방산 조성 분석

본 연구는 국내에서 재배되고 있는 포도씨 14종에 대한 식물성 스테롤의 함량과 지방산 조성을 분석하였다. 포도씨의 식물성 스테롤의 함량은 그 품종별로 차이가 있었으나 14품종의 포도씨 모두 β-sitosterol(64.9～119.3 ㎎/100 g)의 함량이 가장 높게 나타났다. 지방산 조성의 비율은 palmitic(16:0, 6.8～16.8%), palmitoleic(16:1, 0.1～0.2%), stearic(18:0, 4.7～5.2%), oleic(18:1, 16.6～26.1%), linoleic(18:2, 16.6～20.1%), linolenic acid(18:3, 0.3～0.5%) 및 arachidic acid(20:0, 0.3～0.5%)로 분석되었다. 국내에서 재배되고 있는 포도씨 14종의 식물성 스테롤과 지방산의 조성은 유사하였으나 그 함량에는 차이가 있었다. 14품종의 포도씨 중 국내에서 가장 많이 경작되고 있는 Campbell early는 식물성스테롤의 함량과 지방산 조성에 있어서 비교적 우수한 함량을 보였다. 따라서 Campbell early를 가공함으로써 포도씨유 등과 같은 우수한 품질의 가공품 생산이 가능할 것으로 기대된다.

Dysregulation of Lipid and Cholesterol Metabolism in High Fat Diet Fed Hyperlipidemic Rats: Protective Effect of Sida rhomboidea. roxb Leaf Extract

The present study was undertaken to evaluate the efficacy of freeze dried extract of Sida rhomboidea. roxb leaves (FESR) on alteration in lipid and cholesterol metabolism in high fat diet induced hyperlipidemia in experimental rats. Plasma and hepatic lipid profiles, lipid and cholesterol metabolizing enzymes in target tissues and fecal total lipids and bile acid contents were evaluated in FESR treated normolipidemic and hyperlipidemic rats. These results were compared with synthetic hypolipidemic drug lovastatin (LVS). Results indicate that FESR was able to positively regulate induced experimental hyperlipidemia by significant alteration in plasma and tissue lipid profiles. These results can be attributed to reduced absorption, effective elimination and augmented catabolism of lipids and cholesterol possibly due to high content of saponin and phytosterols in S. Rhomboidea. roxb (SR). Use of SR extract as a potential therapeutic agent against hyperlipidemia is indicated.

Establishment of Croton stellatopilosus Suspension Culture for Geranylgeraniol Production and Diterpenoid Biosynthesis

Diterpenoids in higher plants are biosynthesized from isoprene units obtained from two distinct pathways: the mevalonate pathway and the deoxyxylulose phosphate pathway. The metabolic partitioning of both pathways in plant species is dependent upon the type of culture. In order to study the diterpenoid biosynthesis in Croton stellatopilosus cell culture, callus culture was firstly induced from C. stellatopilosus young leaves in Murashige and Skoog (MS) medium in the presence of 1.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D), 1.0 mg/l benzyladenine (BA), 3% (w/v) sucrose and 0.8% (w/v) agar. The suspension culture was further induced from its callus in the same medium without gelling agent. Detection of diterpenoid accumulation by gas chromatography-mass spectrometry revealed that a cell culture could accumulate a low amount of geranylgeraniol (GGOH) and a high content of fatty acids and phytosterols. To improve the GGOH production, the culture conditions were optimized by medium manipulation in terms of hormonal factors. The growth rates of cell cultures were similar in all kinds of media. The GGOH production curve indicated that GGOH plays an important role as a primary metabolite in the cell culture. The optimum medium for GGOH production was MS medium supplemented with 2.0 mg/l 2,4-D and 2 mg/l BA that could produce GGOH with a yield of 1.14 mg/g FW.

Phytosterols, Cholesterol Absorption and Healthy Diets

The purpose of this review is to outline the emerging role of dietary phytosterols in human health. Dietary saturated fat, cholesterol and fiber are currently emphasized in the reduction of low-density lipoprotein cholesterol levels. However, other dietary components such as phytosterols may have equivalent or even larger effects on circulating cholesterol and need further study with respect to the potential for coronary heart disease risk reduction. Phytosterol effects were not considered in classic fat-exchange clinical trials and may account for some of the differences attributed to the food fats studied. Phytosterols reduce cholesterol absorption while being poorly absorbed themselves and the effects can be studied in human subjects in single-meal tests using stable isotopic tracers. Because phytosterols are insoluble and biologically inactive when purified, careful attention needs to be given to ensuring that commercial supplement products are rendered bioavailable by dissolution in fat or by emulsification. Recent work shows that phytosterols in natural food matrices are also bioactive. The retention of phytosterols during food manufacturing and the use of foods with high phytosterol content may constitute an alternative to the use of supplements.

Neutral sterols of representatives of two groups of hemiptera and their correlation to ecdysteroid content

AbstractThe sterols of four species of Pentatomomorpha—Oncopeltus fasciatus (Dallas), Nezara viridula (L.), Dysdercus cingulatus (F.), and Podisus maculiventris (Say)—and threé species of Cimicomorpha—Rhodnius prolixus Stal, Arilus cristatus (L), and Cimex lectularius (L.)—were isolated and examined in order to compare neutral sterol utilization and content with the known ecdysteroids of these species. In the phytophagous Pentatomomorpha, O. fasciatus, N. viridula, and D. cingulatus, the low content of cholesterol and the high content of C28 and C29 phytosterols (< 1% and > 99% of the tissue sterols, respectively) indicated that these species are unable to dealkylate the C‐24 position of sterols. These insects appear to have adapted to the challenge of both insufficient dietary cholesterol and inability to dealkylate phytosterols by evolving the ability to produce a C28 ecdysteroid (makisterone A). The secondarily predacious P. maculiventris has adequate cholesterol available for C27 ecdysteroid production, but appears to have retained the ecdysteroid biosynthetic pathways of its phytophagous ancestors because it produces a C28 ecdysteroid. Cholesterol was the major sterol of each of the three species of Cimicomorpha, and these insects are only able to produce C27 ecdysteroids.