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

Evaluation of sterols as markers of fungal spoilage in red pepper powder

Red pepper powder (RPP) made from ground dried red pepper (Capsicum annuum L.) is prone to adulteration with fungal-spoiled RPP to gain unfair profits in Korea. This study aimed to investigate the effects of fungal infection on the ergosterol and phytosterol content of RPP and evaluate the potential of the sterol content as a marker for identifying fungal-spoiled RPP. Ergosterol was detected only in fungal-spoiled RPP and not in unspoiled RPP [ Collapse

Key Words

• Adulteration
• Alternaria alternata
• Colletotrichum acutatum
• Ergosterol
• Fungal spoilage
• Phytosterols

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MESH Headings

• Capsicum/microbiology
• Capsicum/chemistry
• Food Contamination/analysis
• Fungi/metabolism
• Fungi/isolation & purification
• Sterols/analysis
• Powders/chemistry
• Biomarkers/analysis
• Phytosterols/analysis
• Ergosterol/analysis

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Affiliation(s)

Eunji Choi Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, South Korea.
Hyang Sook Chun Department of Food Science & Technology, Chung-Ang University, Anseong 17546, South Korea.
Joong-Hyuck Auh Department of Food Science & Technology, Chung-Ang University, Anseong 17546, South Korea.
Sangdoo Ahn Department of Chemistry, Chung-Ang University, Seoul 06974, South Korea.
Byung Hee Kim Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, South Korea.

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MOF-derived nanozyme CuOx@C and its application for cascade colorimetric detection of phytosterols

Phytosterols (PSs), a class of naturally occurring bioactive lipid compounds, have been found to possess a significant cholesterol-lowering effect. In developing countries, the consumption of rapeseed oil is the primary pathway of PS intake for the general population. However, developing low-cost, real-time, and high-throughput screening techniques for PSs remains a challenge. Here, a Cu-based nanocomposite CuOx@C was synthesized via a simple method of the calcination of HKUST-1 and systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The CuOx@C demonstrated excellent peroxidase-like (POD-like) activity, functioning as a peroxidase mimic to facilitate the catalysis of 3,3',5,5'-tetramethylbenzidine (TMB) into its oxidized form (oxTMB), thereby initiating a discernible color response. On the basis of this discovery, a CuOx@C-based colorimetric method for detecting total sterols in rapeseed was successfully constructed via cascade reactions. After optimizing the conditions, the high-throughput screening of total sterols in rapeseed could be completed in only 21 min, which significantly facilitated the sensing of PSs. A linear range of 0.6-6 mg/g was achieved for the detection of total sterols in rapeseed samples, thereby satisfying the requirements for detection. In addition, due to the high stability of CuOx@C and the specificity of cholesterol oxidase, the developed method had excellent stability and selectivity toward PSs, indicating that this work has huge prospects for commercial application. This innovative work overcomes the limitation of the instrumental method and provides a portable and reliable tool for total sterols detection. It can also facilitate the development of oilseeds with a high content of PSs.

Overexpression of the OsFes1A increased the phytosterols content and enhanced drought and salt stress tolerance in Arabidopsis

MAIN CONCLUSION

Overexpression of the rice gene, OsFes1A, increased phytosterol content and drought and salt stress tolerance in Arabidopsis. Phytosterols are key components of the phospholipid bilayer membrane and regulate various processes of plant growth and response to biotic and abiotic stresses. In this study, it was demonstrated that the overexpression of OsFes1A (Hsp70 nucleotide exchange factor Fes1) increased phytosterols content and enhanced tolerance to salt and drought stress in Arabidopsis. In transgenic plants, the average content of campesterol was 17.6% higher than that of WT, and the average content of β-sitosterol reached 923.75 μg/g, with an increase of 1.33-fold. In fes1a seeds, the contents of campesterol and β-sitosterol reduced by 20% and 10.93%, respectively. In OsFes1A transgenic seeds, the contents of campesterol and β-sitosterol increased by 1.38-fold and 1.25-fold respectively. Furthermore, the germination rate of transgenic Arabidopsis was significantly higher than WT under stress (salt, ABA, and drought treatment). Under salt stress, transgenic plants accumulated a lower MDA content, higher chlorophyll content, and POD activity relative to the wild type, while the mutants showed the opposite pattern Our study found multiple other functions of OsFes1A beyond the defined role of Fes1 in regulating Hsp70, contributing to the better understanding of the essential roles of Fes1 in plants. Meanwhile, it provides the theoretical basis for developing high phytosterol crop varieties.

Anthocyanins-natural pigment of colored rice bran: Composition and biological activities

Rice by-products are a potential source of various bioactive substances with great processing potential, which are receiving increasing attention. Among them, rice bran is a by-product of rice milling, with high nutritional value and health benefits. Colored rice bran contains a large amount of anthocyanins responsible for color and bioactivities. And anthocyanins are often added to foods as a natural pigment, serving to enhance both the visual appeal and nutritional value. Recent advances in the composition and bioactivities of four common colored rice bran anthocyanins (black, purple, red, and purple red rice) are reviewed in this paper. Rice bran anthocyanins have been confirmed to exhibit biological potential for human health, with their main biological activities being antioxidant, anti-atherosclerosis, anti-cancer, neuroprotective, retinoprotective, immunomodulatory, anti-aging and anti-obesity effects. The structure of anthocyanins determines their biological activities. The anthocyanins composition of rice bran with different colors varied greatly, while that of rice bran with the same color is also slightly different, which is attributed to the rice varieties, growing environment and cropping conditions. However, it remains necessary to conduct further clinical studies to support the health activities of anthocyanins. The present review provides information value for the further development and comprehensive utilization of rice bran anthocyanins.

In Situ Rapid Analysis of Squalene, Tocopherols, and Sterols in Walnut Oils Based on Supercritical Fluid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry

Quantification of liposoluble micronutrients in large-scale vegetable oil samples is urgently needed, because their health benefits are increasingly emphasized. However, current analytical methods are limited to either labor-intensive preparation processes or time-consuming chromatography separation. In this work, an online oil matrix separation strategy for direct, rapid, and simultaneous determination of squalene, tocopherols, and phytosterols in walnut oil (WO) was developed on the basis of the lipid class separation mode of supercritical fluid chromatography. A single run was completed in 13 min containing 6 min of column cleaning and balancing. Satisfactory limit of detections (0.05-0.20 ng/mL), limit of quantifications (0.15-0.45 ng/mL), recoveries (70.61-101.44%), and matrix effects (78.43-91.62%) were achieved, indicating the reliability of this method. In addition, eight sterol esters were identified in WO, which have not previously been reported. The proposed method was applied to characterize the liposoluble micronutrient profile of WO samples obtained from different walnut cultivars, geographical origins, and processes.

Lipidomic Profiling of Rice Bran after Green Solid-Liquid Extractions for the Development of Circular Economy Approaches

Rice bran is a rather underutilized by-product of the rice industry that nowadays is far from being valorized. In this study, the lipidomic profile of bran of the Italian rice variety, Roma, has been evaluated through ultra performance liquid chromatography-tandem mass spectrometry. Crude lipid extracts were obtained from rice bran treated with different green solvents (1-butanol, ethanol and methyl tert-butyl ether/methanol mixture) in combination with an ultrasonic pre-treatment, and then compared with extracts obtained with standard solvents (chloroform/methanol mixture). Lipid yield, number and type of lipids and composition of prevalent lipid classes extracted were evaluated in order to provide an exhaustive lipid profile of the rice bran and to identify the most efficient green solvent for solid-liquid extractions. Twelve different lipid classes and a maximum of 276 lipids were identified. Ethanol and methyl tert-butyl ether/methanol solvents provided higher lipid extraction yields, the former being the most effective solvent for the extraction of triglycerides and N-acylethanolamines and the latter the most effective for the extraction of diglycerides, phospholipids and ceramides at 4 °C. Moreover, extraction with ethanol at 20 °C gave similar results as at 4 °C in terms of lipid yield and for most of the classes of lipids extracted. Taken together, our results indicate ethanol and methyl tert-butyl ether/methanol as excellent solvents for lipid extraction from rice bran, with the aim to further valorize this food by-product in the perspective of a circular economy.

Natural Polyphenol Recovery from Apple-, Cereal-, and Tomato-Processing By-Products and Related Health-Promoting Properties

Polyphenols of plant origin are a broad family of secondary metabolites that range from basic phenolic acids to more complex compounds such as stilbenes, flavonoids, and tannins, all of which have several phenol units in their structure. Considerable health benefits, such as having prebiotic potential and cardio-protective and weight control effects, have been linked to diets based on polyphenol-enriched foods and plant-based products, indicating the potential role of these substances in the prevention or treatment of numerous pathologies. The most representative phenolic compounds in apple pomace are phloridzin, chlorogenic acid, and epicatechin, with major health implications in diabetes, cancer, and cardiovascular and neurocognitive diseases. The cereal byproducts are rich in flavonoids (cyanidin 3-glucoside) and phenolic acids (ferulic acid), all with significant results in reducing the incidence of noncommunicable diseases. Quercetin, naringenin, and rutin are the predominant phenolic molecules in tomato by-products, having important antioxidant and antimicrobial activities. The present understanding of the functionality of polyphenols in health outcomes, specifically, noncommunicable illnesses, is summarized in this review, focusing on the applicability of this evidence in three extensive agrifood industries (apple, cereal, and tomato processing). Moreover, the reintegration of by-products into the food chain via functional food products and personalized nutrition (e.g., 3D food printing) is detailed, supporting a novel direction to be explored within the circular economy concept.

Integrated Technology for Cereal Bran Valorization: Perspectives for a Sustainable Industrial Approach

Current research focuses on improving the bioaccessibility of functional components bound to cereal bran cell walls. The main bioactive components in cereal bran that have major biological activities include phenolic acids, biopeptides, dietary fiber, and novel carbohydrates. Because of the bound form in which these bioactive compounds exist in the bran matrix, their bioaccessibility is limited. This paper aims to comprehensively analyze the functionality of an integrated technology comprising pretreatment techniques applied to bran substrate followed by fermentation bioprocesses to improve the bioaccessibility and bioavailability of the functional components. The integrated technology of specific physical, chemical, and biological pretreatments coupled with fermentation strategies applied to cereal bran previously-pretreated substrate provide a theoretical basis for the high-value utilization of cereal bran and the development of related functional foods and drugs.

The Effect of Stabilized Rice Bran Addition on Physicochemical, Sensory, and Techno-Functional Properties of Bread

Rice bran (RB) is a valuable byproduct derived from rice milling that represents an excellent opportunity for dietary inclusion. Bioactive components with antioxidant potential have been reported in RB, gaining the considerable attention of researchers. However, RB requires a stabilization process after milling to prevent it from becoming rancid and promote its commercial consumption. The aim of this study was to evaluate the effects of substituting stabilized rice bran (SRB) for wheat flour at levels of 10, 15, 20 and 25% on the proximate composition, dietary fiber, dough rheology, antioxidant properties, content of bioactive compounds, and sensory attributes of white wheat-based bread. Results indicated that the incorporation of SRB increased the bread’s insoluble dietary fiber, phytic acid, total polyphenol content, γ-oryzanol, γ-aminobutyric acid, and antioxidant properties, while decreased its water absorption capacity, elasticity, volume, β-glucans, and soluble dietary fiber content. Moreover, substituting wheat flour for SRB at levels higher than 15% affected sensory attributes, such as color, odor, flavor, and softness. This study highlights the potential application of SRB flour in bread-making to increase nutritional, and functional properties of white wheat bread.

Simultaneous Analysis of Free/Combined Phytosterols in Rapeseed and Their Dynamic Changes during Microwave Pretreatment and Oil Processing

Here, a simple, efficient, and rapid solid phase extraction-gas chromatography (SPE–GC) method was developed for the simultaneous analysis of free/combined phytosterols in rapeseed and their dynamic changes during microwave pretreatment and oil processing. First, by comparing different methods for extracting free/combined phytosterols from rapeseed and rapeseed cake, the Folch method was considered to be the optimal method and was selected in subsequent experiments. Subsequently, the extraction method was validated by determining the recoveries of standards (brassinosterol, campesterol, β-sitosterol and cholesteryl oleate) spiked in rapeseed and rapeseed oil samples, and the recoveries were in the range from 82.7% to 104.5% and 83.8% to 116.3%, respectively. The established method was applied to study the dynamic changes of the form and content of phytosterols in rapeseed and its products (rapeseed oil and cake) during rapeseed microwave pretreatment and the oil production process. Additionally, the results showed that more than 55% of the free/combined phytosterols in rapeseed were transferred to rapeseed oil during the oil processing, and this proportion will increase after microwave pretreatment of rapeseed. This work will provide analytical methods and data support for a comprehensive understanding of phytosterols in rapeseed and its products during oil processing.