Preparation and characterization of foxtail millet bran oil using subcritical propane and supercritical carbon dioxide extraction

Advances in the novel and green-assisted techniques for extraction of bioactive compounds from millets: A comprehensive review

Millets are rich in nutritional and bioactive compounds, including polyphenols and flavonoids, and have the potential to combat malnutrition and various diseases. However, extracting these bioactive compounds can be challenging, as conventional methods are energy-intensive and can lead to thermal degradation. Green-assisted techniques have emerged as promising methods for sustainable and efficient extraction. This review explores recent trends in employing green-assisted techniques for extracting bioactive compounds from millets, and potential applications in the food and pharmaceutical industries. The objective is to evaluate and comprehend the parameters involved in different extraction methods, including energy efficiency, extraction yield, and the preservation of compound quality. The potential synergies achieved by integrating multiple extraction methods, and optimizing extraction efficiency for millet applications are also discussed. Among several, Ultrasound and Microwave-assisted extraction stand out for their rapidity, although there is a need for further research in the context of minor millets. Enzyme-assisted extraction, with its low energy input and ability to handle complex matrices, holds significant potential. Pulsed electric field-assisted extraction, despite being a non-thermal approach, requires further optimization for millet-specific applications, are few highlights. The review emphasizes the importance of considering specific compound characteristics, extraction efficiency, purity requirements, and operational costs when selecting an ideal technique. Ongoing research aims to optimize novel extraction processes for millets and their byproducts, offering promising applications in the development of millet-based nutraceutical food products. Therefore, the current study benefits researchers and industries to advance extraction research and develop efficient, sustainable, and scalable techniques to extract bioactive compounds from millets.

Characterization of Wei Safflower Seed Oil Using Cold-Pressing and Solvent Extraction

Wei safflower seed oil (WSO) prepared by the cold pressing method and organic solvent extraction method was characterized in this study. The yield of cold-pressed WSO (CP-WSO) was inferior to that of n-hexane-extracted WSO (HE-WSO). The physicochemical properties (refractive index, density, iodine value, insoluble impurities) and fatty acid compositions were similar, and both were rich in linoleic acid. However, CP-WSO had better color and less solvent residue. The type and content of vitamin E in CP-WSO was also superior to that in HE-WSO, which explained the high oxidative stability of CP-WSO in the Rancimat test. Our results provide a reference for the development of Wei safflower seed oil.

Development of a Comprehensive Quality Evaluation System for Foxtail Millet from Different Ecological Regions

Foxtail millet (Setaria italica L.) is a critical grain with high nutritional value and the potential for increased production in arid and semiarid regions. The foxtail millet value chain can be upgraded only by ensuring its comprehensive quality. Thus, samples were collected from different production areas in Shanxi province, China, and compared in terms of quality traits. We established a quality evaluation system utilizing multivariate statistical analysis. The results showed that the appearance, nutritional content, and culinary value of foxtail millet produced in different ecological regions varied substantially. Different values of amino acids (DVAACs), alkali digestion values (ADVs), and total flavone content (TFC) had the highest coefficients of variation (CVs) of 50.30%, 39.75%, and 35.39%, respectively. Based on this, a comprehensive quality evaluation system for foxtail millet was established, and the quality of foxtail millet produced in the five production areas was ranked in order from highest to lowest: Dingxiang > Zezhou > Qinxian > Xingxian > Yuci. In conclusion, the ecological conditions of Xinding Basin are favorable for ensuring the comprehensive quality of foxtail millet. .

Extraction of oil, carotenes and tocochromanols from oil palm (Elaeis guineensis) fruit with subcritical propane

This work aims to screen the extraction of oil and bioactive compounds including carotenes and tocochromanols from oil palm fruit with subcritical propane and without using a cosolvent. The overall extraction curves of palm oil with subcritical propane were studied and compared to those extracted with supercritical carbon dioxide. Carotenes and tocochromanols were evaluated not only in the extracted oil, but also in the oil of residual fiber in order to calculate the efficiency to recover these valuable compounds. The experimental results showed that oil yield of up to 70 % could be obtained within 120 minutes with subcritical propane at 50 bar and a flow rate of 35 kg·h−1·kg−1. It was also shown that compressed propane is an excellent solvent for the extraction of oil enriched in carotenes and tocochromanols. Subcritical propane extraction can be used as an alternative process for the simultaneous recovery of these valuable minor components from palm fruit.

Comparison of extraction methods for active biomolecules using sub-critical dimethyl ether and n-butane

Several extraction methods are used to isolate natural compounds, and recent approaches utilize subcritical or supercritical extraction media. In this paper we compare extraction methods based on subcritical eluents, dimethyl ether (sC-DME) and n-butane (sC-nB), under mild conditions, using coffee beans and powder as an exemplary raw material. The parameters to be controlled to improve the extraction are considered, and the resulting data discussed. The results obtained display higher selectivity of sC-DME for caffeine (1.9%w/w sC-DME vs. 1.7%w/w sC-nB, on dry extract) and a good yield (0.479 mg/g of caffeine from green coffee beans) compared to, e.g., supercritical carbon dioxide (SC-CO2), which shows 0.32 mg/g of caffeine at higher pressure and temperature (25 MPa, 40 °C). We also discuss some technical implementations for optimizing the use of sub-critical eluents through proper combinations of pressure and temperature. We show that extraction processes based on sub-critical eluents are easy to operate and efficient, and can be easily automated.

Antidiarrheal Effect of Fermented Millet Bran on Diarrhea Induced by Senna Leaf in Mice

Bacillus natto is a kind of probiotic with various functional characteristics, which can produce a lot of nutrients during growth and reproduction. Bacillus natto was used as strain, the number of viable bacteria and the content of soluble dietary fiber in millet bran were used as indexes to study the effects of inoculum size, fermentation time, and fermentation temperature on the fermentation effect, and the optimal fermentation conditions were determined by a response surface experiment. The antidiarrhea effect of fermented millet bran prepared under the best technological conditions was evaluated. The results showed that the optimum fermentation conditions were as follows: inoculum size was 7.48%, fermentation time was 47.04 h, and fermentation temperature was 36.06 °C. Under the optimal fermentation conditions, the viable bacteria count of millet bran was 8.03 log CFU/mL and the soluble dietary fiber content was 12.14%. The fermented millet bran can significantly reduce the intestinal thrust rate and serum levels of IL-6, IL-12, and TNF-α, and significantly increase the secretion of SIgA in the intestinal mucosa, which can relieve diarrhea induced by senna leaf in mice. The results of this study can provide the scientific basis for deep processing of millet bran and efficient utilization of fermented millet bran, and also provide the theoretical basis for clinical treatment of diarrhea.

Oil Recovery from Dry Grind Ethanol Plant Coproducts Using Ethanol

Corn ethanol bio-refineries are seeking economic processing strategies for recovering oil from their coproducts. The addition of ethanol can be an efficient method to recover the oil from the coproducts as the industry has available ethanol. This study considered the effects of ethanol on oil recovery from distillers’ dried grains with solubles (DDGS) and oil partitioning from whole stillage (WS) on a laboratory scale. Ethanol was added with original and heavier fraction DDGS in different temperatures (room temperature ~20 °C, 30 °C, 40 °C, and 50 °C) and solids loadings (20%, 30%, and 40%), and their effects on oil recovery were evaluated. The whole stillage was incubated with ethanol at room temperature (~20 °C) and 50 °C separately to analyze WS’s oil distribution in the liquid and solid phases. The amount of recovered oil from the original and heavier fractions of DDGS varies from 25–45% and 45–70%, respectively, with an increment of temperature. Increasing solids loadings up to 30% had no effect on oil recovery from either DDGS sample. Ethanol treatment in WS resulted in 8–10% higher wet yield of liquid fraction and 17–20% of oil increase in liquid fraction than the control treatment. It is also notable that temperature positively impacted oil partitioning from WS. The results showed that ethanol could improve oil recovery from DDGS and oil partition in WS by varying different process conditions. This outcome is beneficial to ethanol plants to increase corn oil yield using their existing setup and in-situ product.

Purification of Ethyl Linoleate from Foxtail Millet (Setaria italica) Bran Oil via Urea Complexation and Molecular Distillation

Foxtail millet (Setaria italica) bran oil is rich in linoleic acid, which accounts for more than 60% of its lipids. Ethyl linoleate (ELA) is a commercially valuable compound with many positive health effects. Here, we optimized two ELA processing steps, urea complexation (UC) and molecular distillation (MD), using single-factor and response surface analyses. We aimed to obtain a highly concentrated ELA at levels that are permitted by current regulations. We identified the optimal conditions as follows: 95% ethanol-to-urea ratio = 15:1 (w/w), urea-to-fatty acid ratio = 2.5:1 (w/w), crystallization time = 15 h, and crystallization temperature = -6 °C. Under these optimal UC conditions, ELA concentration reached 45.06%. The optimal MD purification conditions were established as follows: distillation temperature = 145 °C and vacuum pressure = 1.0-5.0 × 10^-2 mbar. Under these conditions, ELA purity increased to 60.45%. Together, UC and MD were effective in improving the total concentration of ELA in the final product. This work shows the best conditions for separating and purifying ELA from foxtail millet bran oil by UC and MD.

Foxtail millet: a potential crop to meet future demand scenario for alternative sustainable protein

Foxtail millet (Setaria italica), an annual grass plant, produces seeds that possess health-promoting properties owing to its unique protein composition containing a high content of essential amino acids. The mature foxtail seeds mainly consist of proline-rich, alcohol-soluble proteins (prolamin) called setarins, comprising about 60% of the total protein, with less content of disulfide cross-linked proteins than with other cereal and millets. Protein fractionation schemes are an important tool and provide preliminary information on the nature of foxtail proteins for their applications in the field of agriculture, food pharma, and bio-based materials. Variation in the methods of preparation can influence the composition, structure, and nutritional quality of the protein concentrate. Moreover, foxtail protein or its hydrolysate has shown several bioactive effects that can be explored further for the management of chronic diseases in humans. Additionally, owing to its low cost and excellent functional properties of flour and protein concentrate, foxtail millet can be considered as good candidate for replacing animal protein foods. Furthermore, there is huge potential for successfully developing low-cost, protein-rich functional food products helpful in the prevention and management of lifestyle-related chronic diseases. © 2020 Society of Chemical Industry.

Zinc from foliar-applied nanoparticle fertiliser is translocated to wheat grain: A 65Zn radiolabelled translocation study comparing conventional and novel foliar fertilisers

Foliar zinc (Zn) fertilisers can be used to supplement or replace soil applications of Zn in situations where soil properties may decrease the plant bioavailability of Zn. However, conventional foliar Zn formulations such as zinc sulfate can cause leaf damage due to the rapid release of high amounts of Zn²⁺ into leaf tissue which can be locally phytotoxic. Zinc oxide nanoparticles (ZnO-NPs) offer an alternative approach by providing a more sustained release of Zn into leaf tissue, and potentially avoiding the need for multiple applications. We compared the efficacy of ZnO-NPs and microparticles (ZnO-MPs) to that of conventional formulations (ZnCl₂ and ZnEDTA) in wheat. This is the first study to use ⁶⁵Zn radiolabelled formulations and gamma spectrometry to determine the translocation of Zn to the grains and subsequent efficiency of foliar-applied ZnO-NP fertilisers. We found that ZnEDTA was the most efficient fertiliser in terms of the proportion of applied Zn translocated to wheat grain. We also investigated the effect of Zn application rate on fertiliser efficiency. For all forms of Zn, when plants were treated with Zn at 750 mg/L or 75 mg/L, there were no significant differences in the concentration of applied Zn translocated to the grain. This suggests that current Zn application rates could be decreased while still maintaining the nutritional quality of grain. Finally, using photo-stimulated luminescence (PSL) autoradiography and synchrotron-based X-ray fluorescence microscopy (XFM) we showed that the grain distribution of foliar-applied Zn mirrors that of Zn derived from root uptake.

Extraction and Characterization of Flaxseed Oil Obtained with Subcritical n-Butane

In this study, subcritical n-butane was adopted to extract oil from flaxseed. The extraction conditions i.e. extraction temperature, extraction time, and liquid-solid ratio were investigated and optimized by response surface methodology. The flaxseed oil obtained by subcritical n-butane were characterized and compared with those prepared by n-hexane and cold pressing. Results indicated that the optimal combination of parameters was 53.93℃, 56.82 min, and 19.98:1 mL/g. Subcritical n-butane had higher yield (28.75%) than n-hexane and cold pressing. GC analysis indicated that subcritical n-butane extraction had no obvious influence on the fatty acid composition. Nevertheless, the oil obtained by subcritical n-butane with higher contents of phytosterols (2.93 mg/g) and carotenoids (46.56 mg/kg), and presented a higher oxidation stability (9.27 h). Thus, it was suggested that subcritical n-butane extraction is a promising alternative to extract high quality flaxseed oil.

Oleochemical Properties for Different Fractions of Foxtail Millet Bran

Foxtail millet (FM) is one of the oldest cultivated grain crops with a variety of nutritions, and foxtail millet bran (FMB), a by-product of FM milling process, is also rich in variety of nutrient substance. There are four classifications of FMB, namely coarse bran (FMCB), skin bran (FMSB), polished bran (FMPB) and mixed bran (FMMB). Because these nutrients are distributed within the different fractions of FMB, we compared some chemical composition and its oleochemical properties of four FMB samples. Results showed that the oil extracted from FMB is high value-added plant oil. It contains abundant unsaturated fatty acid (UFA), with the main UFAs were linoleic acid (65%~69%) and oleic acid (12~17%), which accounted for more than 80% of the lipids. The main triacylglycerols were trilinolein (LLL) and oleodilinolein (OLL). There were no evident difference on fatty acid, triacylglycerol and sterols profiles for FMSB, FMPB and FMMB, but the contents of amino acids, tocols, squalene and oryzanol were different.

Assessment of Diversity in the Accessions of Setaria italica L. Based on Phytochemical and Morphological Traits and ISSR Markers

This study was carried out to evaluate genetic diversity, phenolic compound composition, and biological activity of Setaria italica L. collected from different parts of South Korea. Antioxidant potential of seeds was estimated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, and antimicrobial activity was determined by evaluating the minimum inhibitory concentration (MIC). Eight phenolic acids and 3 flavonoids were identified and quantified, among which myricetin and salicylic acid were the most dominant phytochemical compounds detected in the majority of accessions. The antioxidant potential of the leaf extracts of all the accessions was significantly higher (ranging from 32.33 ± 1.53 µg mL-¹ in SI-03 to 87.87 ± 1.63 µg mL-¹) in SI-10 than that of the root, stem, or seeds. Among the 15 accessions, methanolic extracts of the SI-15 accession strongly suppressed the growth of Escherichia coli (250 µg mL-¹). Accessions SI-14 and SI-15 showed positive antimicrobial activity against all gram-positive bacteria. Interestingly, extracts of all accessions were more sensitive towards E. coli and Staphylococcus aureus, with MICs ranging from 250 to 1000 µg mL-¹. Three phenolic acids, namely chlorogenic acid, catechin, caffeic acid, naringin, hesperetin, and myricetin, were found to be moderately positively correlated with antioxidant activities. A wide range of diversity was observed in morphological traits, namely plant height (99.33 to 201.33 cm), culm length (67.10 to 160.00 cm), spike length (12.80 to 24.00 cm), 1000 seeds weight 1.44 to 2.91 g), bloom beginning (93.67 to 128.00 days), and full bloom (99.67 to 135 days). A dendogram generated from unweighted pair group method with arithmetic mean clustering (UPGMA) cluster analysis based on the morphological traits and inter simple sequence repeat (ISSR) marker data revealed three major groups. However, no clear correlation between these two different approaches was found. The average Shannon's information index value (I) was 0.492, and it ranged from 0 to 0.693. The average expected heterozygosity (He) was 0.335, and it ranged from 0 to 0.499. The substantial variation in the morphological traits, bioactive properties, and genetic diversity among the accessions may provide useful information for breeding programs attempting to obtain S. italica with improved bioactive properties.

Process Optimization, Characterization and Antioxidant Capacity of Oat (Avena Sativa L.) Bran Oil Extracted by Subcritical Butane Extraction

Oat bran is a traditional agricultural byproduct and rarely used in edible oil processing. In this paper, oat bran oil (OBO) was firstly extracted by subcritical butane extraction (SBE) and the extraction process was optimized using response surface methodology. Three variables involving liquid-to-solid ratio, extraction time and extraction temperature were studied. The optimum conditions for extraction of OBO were obtained as follows: liquid-to-solid ratio 4.30, extraction time 48.15 min, and extraction temperature 46.52 °C. Based on this, an alternative method (SBE-e) for cosolvent (ethanol) was proposed to improve SBE method. Compared to conventional hexane extraction (CHE), the SBE-e had significant effect on yield, bioactive compounds (phytosterols and phenols) and antioxidant capacity (AC) in the extracted OBO. The results indicated that the proposed methods were appropriate for OBO extraction. Additionally, OBO had the potential to be an acceptable substitute for edible oil, owing to its desirable physicochemical characteristics, a balanced fatty acids composition and high antioxidant capacity.

Highly Selective and Considerable Subcritical Butane Extraction to Separate Abamectin in Green Tea

We specially carried out the subcritical butane extraction to separate abamectin from tea leaves. Four parameters, such as extraction temperature, extraction time, number of extraction cycles, and solid-liquid ratio were studied and optimized through the response surface methodology with design matrix developed by Box-Behnken. Seventeen experiments with three various factors and three variable levels were employed to investigate the effect of these parameters on the extraction of abamectin. Besides, catechins, theanine, caffeine, and aroma components were determined by both high-performance liquid chromatography and gas chromatography-mass spectrometry to evaluate the tea quality before and after the extraction. The results showed that the extraction temperature was the uppermost parameter compared with others. The optimal extraction conditions selected as follows: extraction temperature, 42°C; number of extraction cycles and extraction time, 1 and 30 min, respectively; and solid-liquid ratio, 1:10. Based on the above study, the separation efficiency of abamectin was up to 93.95%. It is notable that there has a quite low loss rate, including the negligible damage of aroma components, the bits reduce of catechins within the range of 0.7%-13.1%, and a handful lessen of caffeine and theanine of 1.81% and 2.6%, respectively. The proposed method suggested subcritical butane possesses solubility for lipid-soluble pesticides, and since most of the pesticides are attached to the surfaces of tea, thus the as-applied method was successfully effective to separate abamectin because of the so practical and promising method.

Extraction of Fenugreek (Trigonella foenum-graceum L.) Seed Oil Using Subcritical Butane: Characterization and Process Optimization

In this study, the subcritical butane extraction process of fenugreek seed oil was optimized using response surface methodology with a Box-Behnken design. The optimum conditions for extracted oil from fenugreek seed was as follows: extraction temperature of 43.24 °C , extraction time of 32.80 min, and particle size of 0.26 mm. No significant differences were found between the experimental and predicted values. The physical and chemical properties of the oil showed that the oil could be used as edible oil. Fatty acid composition of oils obtained by subcritical butane under the optimum conditions and by accelerated solvent extraction showed negligible difference. The oils were rich in linoleic acid (42.71%-42.80%), linolenic acid (26.03%-26.15%), and oleic acid (14.24%-14.40%). The results revealed that the proposed method was feasible, and this essay shows the way to exploit fenugreek seeds by subcritical butane extraction under the scope of edible oils.

Efficient and eco-friendly extraction of corn germ oil using aqueous ethanol solution assisted by steam explosion

An improved aqueous extraction method has been established for extraction of oil from corn germs. This method primarily included steam explosion pretreatment and aqueous ethanol extraction. Process variables such as steam pressure, resident time, particle size and ethanol concentration were investigated. The highest yield of 93.74 % was obtained when ground steam-exploded corn germ (1.3 MPa, 30 s, 30-35 μm particle size) was treated with 30 % (v/v) aqueous ethanol for 2 h, at 60 °C and pH 9.0. The residual oil content in water and sediment phase decreased dramatically to 4 % and 3 %, respectively. The enhancement mechanism of the process induced by steam explosion was analyzed by confocal laser scanning microscope (CLSM). The quality of extracted crude oil was also investigated. The results showed that the quality of extracted oil was superior to commercial oils.

Assessment of Egg Yolk Oil Extraction Methods of for ShiZhenKang Oil by Pharmacodynamic Index Evaluation

To assess the extraction methods of egg yolk oil in ShiZhenKang (SZK) oil, which is used to treat eczema, a mice model of eczema was established by using 2,4-dinitrochlorobenzene (DNCB). The therapeutic effects of egg yolk oil extracted by different methods from SZK oil on the model of acute eczema in mice were evaluated. The oil yield rate of ethanol extraction is 42.06%. Its egg yolk oil is orange and has a rich, sweet, egg smell. Moreover, the SZK oil prepared from it has a very good therapeutic effect on the model of acute eczema in mice. The alcohol extraction method is the preferable method according to a comprehensive evaluation of each index of seven kinds of methods to extract the egg yolk oil.