Simultaneous Determination of Free Phytosterols and Tocopherols in Vegetable Oils by an Improved SPE–GC–FID Method

Phytosterols in Plant-Derived Foods: Recent Updates in Extraction and Analysis Methods

The physiological and officinal functions of phytosterols are of great significance, and recent dietary guidelines have underscored the significance of incorporating them into a balanced diet. Furthermore, it exhibits inhibitory effects on tumor growth, stimulates cellular immunity, possesses anti-inflammatory, antioxidant, and antidiabetic properties. To gain a more comprehensive understanding of the role of phytosterols in public health, it is crucial to establish simple, rapid, eco-conscious, efficient, and highly sensitive techniques for their extraction and determination across various matrices. This review presents a thorough overview of various techniques used for extracting and analyzing phytosterols in diverse plant-derived foods, encompassing a range of advanced technologies like solid-phase extraction, microextraction, supercritical fluid extraction, QuEChERS, alongside traditional approaches. The detection techniques include liquid chromatography-based methods, gas chromatography-based methods, supercritical fluid chromatography, and other methodologies. Additionally, we conduct a thorough examination and comparison of various techniques while proposing future prospects.

Steam explosion pretreatment enhances free/combined phytosterol extraction and utilization in rapeseed (Brassica napus L.) and its processed products: Insights from SPE-GC approach

The study investigates the impact of steam explosion pretreatment on the distribution of free and combined phytosterols within rapeseed and its derived products. Utilizing solid phase extraction-gas chromatography (SPE-GC) analysis, we elucidated the composition and distribution of phytosterols in five rapeseed varieties and their corresponding processed oils and cakes. The results indicated that Zhongyou 516 and Xiwang 988 are richer in combined phytosterols, whereas Dadi 199, Zhongyouza 501, and Xiwang 291 have a greater concentration of free phytosterols. Steam explosion pretreatment significantly increased the extraction proportion of combined phytosterols in rapeseeds. Throughout the oil process, more than half of the total phytosterol content, specifically 57.0%, was transferred from the steam explosion-treated rapeseed into the rapeseed oil. The variety Xiwang 291 showed the highest efficiency in this transfer, achieving a rate of 61.7%. The study provides crucial data for the enhancement of rapeseed processing techniques and the efficient utilization of phytosterols. Moreover, the study highlights the potential use of the ratio of free to combined phytosterols as a discriminator for different rapeseed oil varieties, offering valuable insights for quality assurance and product differentiation in the industry.

Tapping into Nature's Arsenal: Harnessing the Potential of Natural Antioxidants for Human Health and Disease Prevention

Numerous natural antioxidants commonly found in our daily diet have demonstrated significant benefits for human health and various diseases by counteracting the impact of reactive oxygen and nitrogen species. Their chemical properties enable a range of biological actions, including antihypertensive, antimicrobial, anti-inflammatory, anti-fibrotic, and anticancer effects. Despite promising outcomes from preclinical studies, ongoing debate persists regarding their reproducibility in human clinical models. This controversy largely stems from a lack of understanding of the pharmacokinetic properties of these compounds, coupled with the predominant focus on monotherapies in research, neglecting potential synergistic effects arising from combining different antioxidants. This study aims to provide an updated overview of natural antioxidants, operating under the hypothesis that a multitherapeutic approach surpasses monotherapy in efficacy. Additionally, this study underscores the importance of integrating these antioxidants into the daily diet, as they have the potential to prevent the onset and progression of various diseases. To reinforce this perspective, clinical findings pertaining to the treatment and prevention of non-alcoholic fatty liver disease and conditions associated with ischemia and reperfusion phenomena, including myocardial infarction, postoperative atrial fibrillation, and stroke, are presented as key references.

Advances and Challenges in Plant Sterol Research: Fundamentals, Analysis, Applications and Production

Plant sterols (PS) are cholesterol-like terpenoids widely spread in the kingdom Plantae. Being the target of extensive research for more than a century, PS have topped with evidence of having beneficial effects in healthy subjects and applications in food, cosmetic and pharmaceutical industries. However, many gaps in several fields of PS's research still hinder their widespread practical applications. In fact, many of the mechanisms associated with PS supplementation and their health benefits are still not fully elucidated. Furthermore, compared to cholesterol data, many complex PS chemical structures still need to be fully characterized, especially in oxidized PS. On the other hand, PS molecules have also been the focus of structural modifications for applications in diverse areas, including not only the above-mentioned but also in e.g., drug delivery systems or alternative matrixes for functional foods and fats. All the identified drawbacks are also superimposed by the need of new PS sources and technologies for their isolation and purification, taking into account increased environmental and sustainability concerns. Accordingly, current and future trends in PS research warrant discussion.

Evaluation of trans fatty acids, carbonyl compounds and bioactive minor components in commercial linseed oils

Trans fatty acids (TFAs), associated with the risks of coronary heart disease and diabetes, are formed by isomerization of unsaturated fatty acids during refining of linseed oils. In this study, TFAs and the chemical characteristics (acid value, peroxide value, carbonyl compounds, bioactive minor components and fatty acids) in 32 commercial linseed oils were investigated, and the correlation among them were further analyzed. Results showed that C18:3 TFAs were predominant TFAs in linseed oils and about 9% of the samples had TFA contents above 2 g/100 g fat, as well as the average level of TFA in the refined samples was higher than that in the unrefined oils. The correlation analyses suggested C18:3 TFAs exhibited significant negative correlations with acid value, levels of acetone, trans-2-nonenal, campesterol and α-linolenic acid. These results provided a comprehensive insight of TFAs in linseed oil and had important implications for consumers and linseed oil industry.

Vitamin E as an essential micronutrient for human health: Common, novel, and unexplored dietary sources

Vitamin E comprises a group of vitamers that includes tocopherols and tocotrienols. They occur in four homologues according to the number and position of methyl groups attached to the chromanol ring. Vitamin E, a liposoluble antioxidant, may participate as an adjuvant in the prevention and treatment of cardiovascular, neurological, and aging-related diseases. Furthermore, vitamin E has applications in the food industry as a natural additive. In this contribution, the most recent information on the dietary sources of vitamin E, including common, novel, and unexplored sources, is presented. Common edible oils, such as those of corn, olive, palm, rice bran, and peanut, represent the most prominent sources of vitamin E. However, specialty and underutilized oils such as those obtained from tree nuts, fruit seeds, and by-products, emerge as novel sources of this important micronutrient. Complementary studies should examine the tocotrienol content of vitamin E dietary sources to better understand the different biological functions of these vitamers.

Specialty seeds: Nutrients, bioactives, bioavailability, and health benefits: A comprehensive review

Seeds play important roles in human nutrition and health since ancient time. The term "specialty" has recently been applied to seeds to describe high-value and/or uncommon food products. Since then, numerous studies have been conducted to identify various classes of bioactive compounds, including polyphenols in specialty seeds. This review discusses nutrients, fat-soluble bioactives, polyphenols/bioactives, antioxidant activity, bioavailability, health benefits, and safety/toxicology of commonly consumed eight specialty seeds, namely, black cumin, chia, hemp, flax, perilla, pumpkin, quinoa, and sesame. Scientific results from the existing literature published over the last decade have been compiled and discussed. These specialty seeds, having numerous fat-soluble bioactives and polyphenols, together with their corresponding antioxidant activities, have increasingly been consumed. Hence, these specialty seeds can be considered as a valuable source of dietary supplements and functional foods due to their health-promoting bioactive components, polyphenols, and corresponding antioxidant activities. The phytochemicals from these specialty seeds demonstrate bioavailability in humans with promising health benefits. Additional long-term and well-design human intervention trials are required to ascertain the health-promoting properties of these specialty seeds.

Novel Fast Chromatography-Tandem Mass Spectrometric Quantitative Approach for the Determination of Plant-Extracted Phytosterols and Tocopherols

Phytosterols and tocopherols are commonly used in food and pharmaceutical industries for their health benefits. Current analysis methods rely on conventional liquid chromatography, using an analytical column, which can be tedious and time consuming. However, simple, and fast analytical methods can facilitate their qualitative and quantitative analysis. In this study, a fast chromatography-tandem mass spectrometric (FC-MS/MS) method was developed and validated for the quantitative analysis of phytosterols and tocopherols. Omitting chromatography by employing flow injection analysis—mass spectrometry (FIA-MS) failed in the quantification of target analytes due to analyte-to-analyte interferences from phytosterols. These interferences arise from their ambiguous MS fingerprints that would lead to false identification and inaccurate quantification. Therefore, a C18 guard column with a 1.9 µm particle size was employed for FC-MS/MS under isocratic elution using acetonitrile/methanol (99:1 v/v) at a flow rate of 600 µL/min. Analyte-to-analyte interferences were identified and eliminated. The false peaks could then be easily identified due to chromatographic separation. In addition, two internal standards were evaluated, namely cholestanol and deuterated cholesterol. Both internal standards contributed to the observed analyte-to-analyte interferences; however, adequate shift in the retention time for deuterated cholesterol eliminated its interferences and allowed for an accurate quantification. The method is fast (1.3 min) compared to published methods and can distinguish false peaks observed in FIA-MS. Seven analytes were quantified simultaneously, namely brassicasterol, campesterol, stigmasterol, β-sitosterol, α-tocopherol, δ-tocopherol, and γ-tocopherol. The method was successfully applied in the quantitative analysis of phytosterols and tocopherols present in the unsaponifiable matter of canola oil deodorizer distillate (CODD). β-sitosterol and γ-tocopherol were the most abundant phytosterols and tocopherols, respectively.

Occurrence of Tocols in Foods: An Updated Shot of Current Databases

Tocols are present in various foods, mostly in fruits and in plant seeds. Edible oils are the most important natural dietary sources of tocopherols and tocotrienols, collectively known as tocols. Tocopherols and tocotrienols are considered beneficial for their antioxidant effect which impacts on prevention of different health conditions. This perspective is addressed to give an updated picture of the tocol occurrence in foods. Moreover, the current state of the art of tocols in updated databases is explored and commented outlining their importance and future trends.