Partition Behaviors of Different Polar Anthocyanins in Aqueous Two-Phase Systems and Extraction of Anthocyanins from <Emphasis Type="Italic">Nitraria tangutorun</Emphasis> Bobr. and <Emphasis Type="Italic">Lycium ruthenicum</Emphasis> Murr.

This study aimed to investigate the partition behaviors of various polar anthocyanins in NaH₂PO₄/(NH₄)₂SO₄-ethanol aqueous two-phase systems (ATPS) and to extract anthocyanins from Nitraria tangutorun Bobr. and Lycium ruthenicum Murr. Anthocyanins in Hibiscus sabdariffa L., Morus atropurpurea Roxb., N. tangutorun, and L. ruthenicum were profiled using HPLC-ESI-MS/MS and HPLC-DAD, and the partition behaviors of total anthocyanins and main anthocyanins were studied. The partition coefficient of anthocyanins increased with increased hydrophobicity, and low-polarity anthocyanins exhibited a higher preference for the top phase in NaH₂PO₄/(NH₄)₂SO₄-ethanol ATPS. Additionally, the NaH₂PO₄-ethanol ATPS gave higher selectivity and total anthocyanin yield than the (NH₄)₂SO₄-ethanol system. Extraction at 65 °C for 45 min and at 45.5 °C for 45 min using 28% NaH₂PO₄ and 26% ethanol (w/w) led to the recovery of 98.91 ± 0.03% of N. tangutorun anthocyanins (3.62 ± 0.05 mg/g) and 99.84 ± 0.01% of L. ruthenicum anthocyanins (13.16 ± 0.29 mg/g) from raw material; more than 70% of total sugars were removed in a single step. NaH₂PO₄-ethanol aqueous two-phase extraction is a promising method for extracting anthocyanins from N. tangutorun and L. ruthenicum.     

Green Approach for Sample Preparation and Determination of Anthocyanins from <Emphasis Type="Italic">Lycium ruthenicum</Emphasis> Murr. Using a <Emphasis Type="Italic">β-</Emphasis>Cyclodextrin-Based Extraction Method Coupled with UPLC-DAD Analysis

This study aimed to develop and optimize a β-cyclodextrin (β-CD)-based technique for extracting anthocyanins from Lycium ruthenicum Murr. and to establish a ultra-high-performance liquid chromatography-diode array detector (UPLC-DAD) method for their analysis. β-CD solutions produced higher extraction yields of petunidin-3-O-(trans-p-coumaroyl)-rutinoside-5-O-glucoside and total anthocyanins from L. ruthenicum fruit than did pure water and aqueous hydroxypropyl-β-cyclodextrin (HPβ-CD) and ethanol and methanol solutions. Extraction at 50 °C for 30 min using 1.65% β-CD solution and a liquid/solid ratio of 15:1 produced the optimal extraction yield of L. ruthenicum anthocyanins. A UPLC-DAD method was developed for the determination of L. ruthenicum anthocyanins using an ethanol-based mobile phase, and the primary anthocyanins were identified using two-dimensional LC-MS/MS. Method validation showed that the developed method was accurate, stable, and reliable for the analysis of petunidin-3-O-(trans-p-coumaroyl)-rutinoside-5-O-glucoside and total anthocyanins from L. ruthenicum fruit. The present study showed that β-CD-based extraction coupled with UPLC-DAD analysis is an efficient and green method for the extraction and analysis of anthocyanins from L. ruthenicum fruit.     

Composition of Carotenoids in <Emphasis Type="Italic">Scenedesmus protuberans</Emphasis>: Application of Chromatographic and Spectroscopic Methods

This study aimed to identify and determine the carotenoids from green microalga, Scenedesmus protuberans using analytical techniques. Identification of carotenoids was realized by comparing their absorption and mass spectral data with those of reference standards available and reported values. Chromatographic data were then combined with the spectroscopic information. The separation of carotenoids was achieved by C₃₀ column and high-performance liquid chromatography-diode array detection was used for their determination. In the present work, the carotenoid content of S. protuberans was found to be 1.45 mg/g of violaxanthin, 2.47 mg/g of all-trans-lutein, 0.15 mg/g of all-trans-α-carotene, 0.55 mg/g of all-trans-β-carotene, and 0.20 mg/g of 9 or 9′-cis-β-carotene. Due to lack of their standards, the amount of all-trans-loroxanthin and cis-isomers of other carotenoids could not be quantified. In order to validate the method, Certified Reference Material (BCR 485-Mixed vegetables) was used. In conclusion, this study can serve as a reference for the analysis of carotenoids in other microalgae.     

Design of Sonotrode Ultrasound-Assisted Extraction of Phenolic Compounds from <Emphasis Type="Italic">Psidium guajava</Emphasis> L. Leaves

Psidium guajava L. has gained a special attention as health plant due to the presence of phenolic compounds. Box-Behnken design (BBD) has been applied for the extraction of target compounds from guava leaves via sonotrode ultrasound-assisted extraction (UAE). Different extraction times (5, 30, and 55 min), ratios of ethanol/water (50, 75, and 100% (v/v)), and ultrasound (US) power (80, 240, and 400 W) were tested to find their effect on the sum of phenolic compound (SPC), flavonols and flavan-3-ols via HPLC-ESI-QqQ-MS, and antioxidant activity (DPPH and TEAC assays). The best process conditions were as follows: 40 min, 60% ethanol/water (v/v), and 200 W. Established method has been used to extract phenolic compounds in two guava leaves varieties (pyrifera and pomifera). Pyrifera var. showed greater values of the SPC via HPLC-ESI-QqQ-MS (49.7 mg/g leaf dry weight (d.w.)), flavonols (12.51 mg/g d.w.), flavan-3-ols (7.20 mg/g d.w.), individual phenolic compounds, and antioxidant activity (8970 ± 5 and 465 ± 6 μmol Trolox/g leaf d.w, respectively) than pomifera var. Conventional extraction showed lower amounts of phenolic compounds (7.81 ± 0.03 and 4.64 ± 0.01 mg/g leaf d.w. for flavonols and flavan-3ols, respectively) in comparison to the ultrasound-assisted ones.     

A Powerful Analytical Strategy Based on QuEChERS-Dispersive Solid-Phase Extraction Combined with Ultrahigh Pressure Liquid Chromatography for Evaluating the Effect of Elicitors on Biosynthesis of <Emphasis Type="Italic">trans</Emphasis>-Resveratrol in Grapes

A powerful methodological approach based on modified quick, easy, cheap effective, rugged, and safe (QuEChERS) extraction technique, followed by cleanup dispersive solid-phase extraction (dSPE) and combined with ultrahigh pressure liquid chromatography (UHPLC), is presented in this paper, for the rapid determination of the health-promoting phytoalexin, trans-resveratrol, in grapes. This is the first time, to our knowledge, that the combination QuEChERS-dSPE/UHPLC-PDA has been used for trans-resveratrol quantification in grapes. The method has been validated according to European Union Decision 2002/657/EC, in terms of selectivity, linearity, sensitivity, instrument LOD and method LOQ, accuracy, precision, extraction efficiency, and interference assessment. Validation experiments revealed sufficient linearity (R ²?=?0.9931) within the established concentration range confirmed by Mandel’s fitting test. The sensitivity was good with method detection limit (LOD) of 0.003 μg/mL and quantification limit (LOQ) of 0.010 μg/mL. Optimum QuEChERS-dSPE/UHPLC-PDA conditions led to recoveries of the target analyte in grape samples ranging between 75.1 and 99.7 % and precisions in the 0.9–4 % range (RSD, n?=?18). The method also afforded satisfactory results in terms of extraction efficiency and interference assessment and provides a valuable and promising tool for determination of trans-resveratrol in grapes with a high resolution within 8 min and a total analysis time of 11 min. The validated methodology was applied to evaluate the effect of the use of elicitors, namely benzothiadiazole and methyl jasmonate, in trans-resveratrol biosynthesis on Vitis vinifera Monastrell grapes. The results obtained revealed an increase of trans-resveratrol level of 2-fold for grapes treated with benzothiadiazole and 3.5-fold for grapes treated with methyl jasmonate.     

Optimization of ultrasonic-assisted extraction of phenolic compounds from <Emphasis Type="Italic">Justicia spicigera</Emphasis> leaves

A Box–Behnken design (Extraction-time, pulse-cycle, sonication-amplitude) was employed to extract phenolic compounds from Justicia spicigera leaves by ultrasonic-assisted extraction. The muicle leaves extracts were analyzed measuring total phenolic compounds and antioxidant capacity. According to response surface methodology the optimal conditions of ultrasonic-assisted extraction to obtain the highest soluble phenolic content were 2 min (extraction time) for 0.7 s (pulse cycle) at 55% of sonication amplitude. Under these optimal conditions, the total phenolic content was higher when was used ultrasonic-assisted extraction (54.02 mg/g) than stirring (46.46 mg/g) and thermal decoction (47.76 mg/g); however, the antioxidant capacity from J. spicigera extracts did not increase by ultrasonic-assisted extraction. The extracts or aqueous infusions from J. spicigera leaves are used for therapeutic proposes, therefore the ultrasonic-assisted extraction is a useful technology to improve the extraction of phytochemicals from J. spicigera leaves.     

Screening of the phenolic profile and their antioxidative activities of methanol extracts of <Emphasis Type="Italic">Myrica rubra</Emphasis> fruits,leaves and bark

The phenolic composition in dried Myrica rubra fruits, leaves and bark were investigated for evaluation of its contribution to the antioxidant activity. The fruits, leaves and bark have the abundant phenolic compounds with the total phenolic content of 0.673, 0.276 and 0.136 mg/g (GA equivalents/FW), respectively. Ten phenolic compounds were isolated and identified in methanol extracts of Myrica rubra fruits by GC–MS analysis. Less phenolic compounds were found in leaves and bark than in fruits. However, the leaves and bark contain much higher concentrations of the trans-resveratrol over 100 μg/g than in fruits. The total antioxidant activities against the ·DPPH radical of those three samples were 0.438, 0.184 and 0.092 mg/g (Trolox equivalents/FW), respectively. The quantitative results indicated that a good correlation between the total antioxidant activity, total phenolic contents, and abundance of individual phenolic compound in Myrica rubra plants.     

Characterisation of phenolic phytochemicals and quality changes related to the harvest times from the leaves of Korean purple perilla (Perilla frutescens)

The objective of this study was to investigate the profiles of phenolic phytochemicals in the leaves of Korean purple perilla (cv. Bora, Perilla fructescens) using reversed-phase C₁₈ column chromatography and HPLC with DAD-ESI/MS analysis. Changes in their contents were also the first reported through eight different harvest times during two months. They were characterised as five anthocyanins and three phenolic acids including cyanidin-3,5-di-O-glucoside (1), cyanidin-3-O-glucoside (2), cyanidin-3-O-(6-O-caffeoyl)glucoside-5-O-glucoside (3), cyanidin-3-O-(6-O-coumaroyl)glucoside-5-O-glucoside (4), cyanidin-3-O-(6-O-coumaroyl)glucoside (5), caffeic acid (6), rosmarinic acid (7), and rosmarinic acid methylester (8). Significant differences were observed between individual and total phytochemical contents, especially, cyanidin-3-O-(6-O-coumaroyl)glucoside-5-O-glucoside (4) and rosmarinic acid (7) exhibited the predominant constituents. Among different harvest times, the highest content was found with 82.473 mg/g on 21st September, while the lowest was 39.000 mg/g on 17th August. These results may be useful in determining the optimal harvest time at which phenolic phytochemicals reaches a maximum level in mid-September.     

Determination of Seven <Emphasis Type="Italic">N</Emphasis>-nitrosamines in Agricultural Food Matrices Using GC-PCI-MS/MS

The quantitative analytical methods for seven N-nitrosamines including N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosodibutylamine (NDBA), N-nitrosopiperidine (NPIP), N-nitrosopyrrolidine (NPYR), and N-nitrosomorpholine (NMOR) were established for agricultural food matrices. Four food matrices were used for the method development: rice soup as a fatless solid matrix, apple juice as a fatless liquid matrix, corn oil as a fat-rich liquid matrix, and 20 % alcohol as an alcohol matrix. A combination of solid-supported liquid-liquid extraction (SLLE) using Extrelut NT and a solid phase extraction (SPE) using Florisil was employed for fatless matrices. For an alcohol matrix, only SLLE was used without SPE, and liquid-liquid extraction (LLE) was established for a fat-rich matrix. The extract was analyzed by gas chromatography-positive chemical ionization-tandem mass spectrometry (GC-PCI-MS/MS) using ammonia gas as an ion source. Linearity, recovery, repeatability, inter-day precision, reproducibility, and uncertainty were evaluated for method validation using four matrices. Method detection limits for all of the investigated N-nitrosamines were ranged from 0.10 to 0.18 μg/kg for the rice soup, from 0.10 to 0.19 μg/kg for the apple juice, 0.10 μg/kg for the corn oil, and from 0.10 to 0.25 μg/kg for 20 % alcohol, depending on N-nitrosamines. Established methods were applied to determine seven N-nitrosamines in some agricultural food products.     

Sequential Microwave-Ultrasound-Assisted Extraction for Isolation of Piperine from Black Pepper (<Emphasis Type="Italic">Piper nigrum</Emphasis> L.)

Piperine is the natural bioactive component of black pepper (Piper nigrum L.) with several astounding therapeutic properties. In this study, sequential microwave-ultrasound-assisted extraction approach was used for isolation of piperine from black pepper. The effect of various factors such as extraction solvent, particle size of pepper, solvent to solid ratio, microwave power and time and ultrasound temperature and time on the extraction yield of piperine was considered. The maximum extraction yield was 46.6 mg piperine/g pepper which was obtained using ethanol as solvent at the particle size of 0.15 mm, solvent to solid ratio of 20:1, microwave power of 100 W for 1 min, and ultrasound temperature of 50 ^° C for 30 min. This extraction yield was higher than those obtained by Soxhlet (39.1 mg/g), microwave-assisted (38.8 mg/g) and ultrasound-assisted (37.0 mg/g) extractions. The purity of the extracted piperine was 81.4% as determined by HPLC analysis. The FTIR and UV-vis analyses confirmed that the structure of piperine remained intact after extraction and purification which is very important for medicinal applications.     

Optimization of Extraction Parameters of Total Phenolics from <Emphasis Type="Italic">Annona crassiflora</Emphasis> Mart. (Araticum) Fruits Using Response Surface Methodology

In this study, response surface methodology was used to optimize the extraction temperature (25–75 °C) and ethanol concentration (0–70 %, ethanol/water, v/v) to maximize the extraction of total phenolic compounds (TPC) from araticum pulp. The efficiency of the extraction process was monitored over time, and equilibrium conditions were reached between 60–90 min. A second-order polynomial model was adequately fit to the experimental data with an adjusted R ² of 0.9793 (p < 0.0001) showing that the model could efficiently predict the TPC content. Optimum extraction conditions were ethanol concentration of 46 % (v/v), extraction temperature of 75 °C and extraction time of 90 min. Under the optimum conditions, the araticum pulp showed high TPC content (4.67 g GAE/100 g dw) and also high antioxidant activity in the different assays used (46.56 μg/mL, 683.65 μmol TE/g and 1593.72 μmol TE/g for DPPH IC₅₀, TEAC and T-ORAC_FL, respectively). From our extraction procedure, we successfully recovered a significantly higher amount of TPC compared to other studies in the literature to date (1.5–22-fold higher). Furthermore, TPC and antioxidant activity were present in the fruit in levels that are difficult to find in other common fruits. These results expose a potential approach for improving human health through consumption of araticum fruit.     

Effects of organic acid pretreatment on microstructure,functional and thermal properties of unripe banana flour

Starch availability has been implicated in unripe matured banana (Musa species), which when processed yields flour suitable for application in low gluten and composite wheat formulations. Unripe Musa species: Williams, Luvhele, Mabonde and Muomva-red obtained from fruit bunch were pretreated with ascorbic, citric and lactic acids, processed into 50 g of flour and characterised for their functional and thermal properties. Scanning electron microscope of unripe banana flour (UBF) showed varying micrographs of flour, with polygonal for Luvhele, oval for Mabonde, elongated for Muomva-red and between polygonal and spherical for Williams. The bulk density of UBF samples was within the range of 0.66–0.84 g/mL for all organic acid pretreatment while citric acid pretreated UBF had the least browning index. Significant difference (p < 0.05) was recorded in swelling power with no significant difference in water solubility index except for Mabonde UBF. Thermal properties showed single endothermic transition for all UBF samples at various pretreatment concentration. The onset temperature (To) of UBF ranges from 49.82 to 65.59 °C, peak temperature (Tp) from 60.11 to 76.71 °C, conclusion temperature (Tc) from 70.36 to 94.16 °C and enthalpy of gelatinization (ΔH) from 2.61 to 32.24 J/g. Short amylopectin chains present in starch of UBF was attributed to low To, Tp, Tc and ΔH values recorded for Mabonde cultivar, while the contribution of heat-moisture treatment rather than organic acid pretreatment of UBF samples was attributed to different gelatinization and transition temperatures recorded for all cultivars examined.     

A TLC-HPLC Method for Determination of Thiamphenicol in Pig,Chicken, and Fish Feedstuffs

An effective thin-layer chromatography (TLC) purification procedure coupled to high-performance liquid chromatography (HPLC) method was developed for the determination of thiamphenicol (TAP) in pig, chicken, and fish feedstuffs. The feedstuff samples were extracted with ethyl acetate, defatted with n-hexane saturated with acetonitrile, and further purified by TLC. The chromatographic separation was performed on a Waters Symmetry C₁₈ column using an isocratic procedure with acetonitrile-water (21.7:78.3, v/v) at 0.6 mL/min. The ultraviolet (UV) detector was set at a wavelength of 225 nm. The TAP concentrations in feedstuff samples were quantified using a standard curve. Good linear correlations (y?=?162,630x???2381.7, r?>?0.9998) were achieved within the concentration range of 0.05–10.00 μg/mL. The recoveries of TAP spiked at levels of 1, 10, and 100 μg/g ranged from 82.0 to 114.9% with the intra-day and inter-day relative standard deviation (RSD) less than 9.0%. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.02 and 0.03 mg/kg for pig feedstuffs, 0.02 and 0.04 mg/kg for chicken feedstuffs, and 0.02 and 0.03 mg/kg for fish feedstuffs, respectively. This reliable, simple, and cost-effective method could be applied to the routine monitoring of TAP in animal feedstuffs.     

Anthocyanins composition and antioxidant activity of two major wild Nitraria tangutorun Bobr. variations from Qinghai-Tibet Plateau

Nitraria tangutorun Bobr., a unique kind of fruit, widely spreads in the Qinghai-Tibet Plateau. In the present study, nine anthocyanins were identified in two variations (purple fruit and red fruit) of N. tangutorun by HPLC/DAD-ESI/MS. Cyanidin-3-O-(trans-p-coumaroyl)-diglucoside (215.76 ± 22.91 mg of Mv3G5G equivalent per 100 g of fresh weight) and pelargonidin-3-O-(p-coumaroyl)-diglucoside (5.13 ± 0.35 mg of Mv3G5G equivalent per 100 g of fresh weight) were the main anthocyanins in the purple and red fruits respectively. In addition, most of the anthocyanins were acylated by coumaric acid, and the rare anthocyanins that naturally presented a coumaric acid in both cis and trans configurations have been detected. Furthermore, the extract of the two variations showed significantly different antioxidant activity (p < 0.01) according to DPPH, ABTS and FRAP assay. Purple fruit possessed higher antioxidant activity than red fruit. There were significant correlations between antioxidant activity and both the total polyphenol content and anthocyanins content. This work is valuable for elucidation of anthocyanins composition in N. tangutorun and for further utilization as a functional food and medicine material.     

Reversed-phase HPLC determination of mangiferin,isomangiferin and hesperidin in <Emphasis Type="Italic"> Cyclopia </Emphasis>and the effect of harvesting date on the phenolic composition of <Emphasis Type="Italic"> C. genistoides</Emphasis>

A reversed-phase HPLC method for separation of polyphenols in honeybush tea (Cyclopia spp.) is presented. Separation of eriodictyol, luteolin, medicagol, formononetin, mangiferin, isomangiferin, hesperetin and hesperidin was investigated. A C12 stationary phase was required to separate mangiferin and isomangiferin. The method was used to quantify the three major polyphenols (mangiferin, isomangiferin and hesperidin) in C. genistoides, C. intermedia, C. maculata and C. sessiliflora and to study the effect of harvesting date on these compounds in two types of C. genistoides. The highest levels of the xanthones, mangiferin (3.61 g/100 g) and isomangiferin (0.54 g/100 g), and the flavanone, hesperidin (1.74 g/100 g), were found for C. genistoides (both xanthones) and C. intermedia, respectively. Cyclopia sessiliflora contained the lowest levels of mangiferin (1.04 g/100 g) and hesperidin (0.29 g/100 g). The mangiferin content of both the Overberg and West Coast types decreased with harvesting date (P <0.05). The Overberg type contained more mangiferin, but hesperidin was more prominent in the West Coast type.     

Extraction and in vitro antioxidant capacity evaluation of phenolic compounds from pigmented aromatic rice (<Emphasis Type="Italic">Oryzae sativa</Emphasis> L.) cultivars

The aroma generating volatile components profile and in vitro antioxidant capacities of different aromatic rice cultivars was determined by GC–MS analysis and in terms of DPPH scavenging activity, lipid peroxidation inhibition, phosphomolybdenum reduction and reducing power assay. The total phenolic content including both free and bound forms in the analyzed aromatic rice cultivars, Mushki budgi (1.62 mg GAE/g), Mushki kandi (1.63 mg GAE/g) and Kamad (1.60 mg GAE/g) were found double the amount as compared to non-aromatic Koshkari (0.86 mg GAE/g) cultivar. The aromatic rice cultivars had also shown higher total flavonoid content and antioxidant activity than non-aromatic rice cultivar (Koshkari). The GC–MS results indicated 21-aromatic compounds present in sufficient quantities in aromatic cultivars and some of them were unique to these cultivars. Among the compounds identified, aldehydes were found in higher quantity followed by alkanes, ketones and esters. Among the aromatic rice cultivars, Mushki budgi and Mushki kandi were found possessing higher quantity of flavoring components such as benzaldehyde, a carcinostatic agent. The cultivars Mushki budgi and Mushki kandi indicated positive correlation of TPC, TFC and the in vitro antioxidant components largely, while the less aromatic Kamad, correlate with only two components viz DPPH and lipid peroxidation.     

Volatile Constituents of Jambolan (<Emphasis Type="Italic">Syzygium cumini</Emphasis> L.) Fruits at Three Maturation Stages and Optimization of HS-SPME GC-MS Method Using a Central Composite Design

The volatile compounds of jambolan (Syzygium cumini L.) fruit were determined at three different maturity stages (unripe, half-ripe, and ripe) by headspace solid-phase microextraction (HS-SPME)–gas chromatography-mass spectrometry (GC-MS) technique using five different fibers (Fused silica PDMS/DVB, DVB/CAR/PDMS, PEG, Stable flex PDMS/DVB, and PDMS). The optimal extraction conditions were evaluated using different variables such as adsorption temperature (minimum 25 °C, maximum 55 °C), salt quantity (minimum 0, maximum 30.0%), and extraction time (min 10, max 30 min). The major classes of compounds identified were ester, terpene, alcohol, aldehyde, and carboxylic acid. Ninety volatile compounds with characteristics aroma attributes were identified, and the primary compounds linked with development of characteristics aroma of ripe jambolan fruit pulp were trans-β-ocimene, β-ocimene, caryophyllene, humulene, D-α-pinene, L-β-pinene, β-pinene, D-limonene, α-terpineol, neo-allo-ocimene, 2-hexenal (E), δ-cadinene, 3-hexen-1-ol, (Z) β-linalool, terpinolene, eremophilene, valencene, 1-hexanol, longipinene, γ-terpinene, γ-muurolene, endo-borneol, o-cymene, nonanal, terpinen-4-ol, β-terpineol, α-muurolene, fenchol, α-fenchene, β-thujene, benzaldehyde, (E)-2-hexenal, β-cadinene, and decanal.     

Effect of sodium selenite on the bacteria growth,selenium accumulation,and selenium biotransformation in <Emphasis Type="Italic">Pediococcus acidilactici</Emphasis>

In this study, the effect of low selenium concentrations on bacteria growth, selenium bioaccumulation, and selenium speciation in Pediococcus acidilactici was investigated. Six different sodium selenite (Na₂SeO₃) solutions with concentrations of 0, 0.5, 1, 2, 3, and 4 mg/L were added in MRS broth for 24 h. Then, the obtained bacterial pellets were weighed. The contents of total selenium and selenium species in the bacterial pellets were measured via optimized enzymatic hydrolysis and HPLC-ICP-MS. The maximum dried P. acidilactici biomass of 1.44 g/L was achieved by utilizing 1 mg/L Na₂SeO₃. By increasing sodium selenite concentrations, total selenium contents were significantly increased from 0.14 to 1.45 mg/g dry weight (p < 0.05). The findings indicated that selenium was favorably incorporated into the bacteria protein fraction and mainly formed selenocysteine. Therefore, selenium-enriched lactic acid bacterium P. acidilactici can deliver a less-toxic, more bioavailable selenium source for human and animal nutrition.     

Glycerides isolated from the aerial parts of <Emphasis Type="Italic">Malva verticillata</Emphasis> cause immunomodulation effects via splenocyte function and NK anti-tumor activity

A preliminary study revealed that a 10 µg/mL n-BuOH fraction of Malva verticillata aerial parts significantly enhanced splenocyte proliferation and induced significant enhancement of natural-killer (NK) cell activity against tumor cells (YAC-1). This study was initiated to identify the principal components that exhibited these activities, and four glycerides were isolated through repeated SiO₂ and ODS column chromatography. Structures of compounds 1–4 were determined to be (2S)-1-O-palmitoyl glyceride, (2S)-1-O-stearoyl glyceride, (2S)-1-O-linolenoyl glyceride, and (2S)-1,2-di-O-linoleoyl glyceride, respectively. Compounds 1–3 showed potential immune-enhancing activity in murine splenocyte and natural-killer (NK) cells at 10 µM. In contrast, compound 4 showed weak activity, indicating the monoacyl glycerides (1–3) are more effective than diacyl glyceride (4). Also, the longer the carbon number of the fatty acid in monoacyl glyceride, the better the activity, and the monoacyl glyceride including an unsaturated fatty acid (3) is more effective than the glycerides including the saturated fatty acids (1–2).     

Development and characterization of reconstituted hydrogel from <Emphasis Type="Italic">Aloe vera</Emphasis> (<Emphasis Type="Italic">Aloe barbadensis</Emphasis> Miller) powder

Structural and rheological characterization of reconstituted hydrogels developed from A. vera non-fibrous alcohol insoluble residue (NFAIR) powder using different methods [viz., shaking (S), heating-shaking (HS), and heating (H)] and concentrations (viz., 0.2–1.6 %, w/v) was carried out. Functional group distribution by FTIR spectroscopy and Congo red (CR) method revealed the presence of acetylated acemannan in A. vera powder. Dynamic oscillation studies of A. vera (NFAIR) fluids at all concentrations of 0.2–1.6 %, w/v, showed gel strength in the order of H > HS > S method. However, in H method, increase in concentration from 0.2 to 1.6 %, w/v showed the conformational transition from semi-diluted solution to weak gel nature. Rheological models described the effect of heating temperatures (HT); 30–90 °C, and times (Ht); 15–60 min on viscoelastic behavior in reconstituted A. vera fluids. The reconstituted A. vera hydrogel prepared with a concentration of 1.6 %, w/v using 50 °C (HT) and 30 min (Ht) condition showed a good agreement with the Power law (storage modulus, G′) and Weak gel model (complex modulus, G*) fitted data (R² > 0.94) resulting higher viscoelastic moduli intercepts; G′₀ (71.5 Pa s ^n′), G″₀ (33.5 Pa s ^n″), lower slopes; n′ (0.22), n″ (0.06), higher network strength (A _F , 121.3 Pa s^1/z ) and number of network (z, 5.3) values. The obtained results suggested that heating at 50 °C/30 min can develop aqueous weak gel networks of A. vera with enhanced gel strength which may be utilized as a novel gelling agent for wide variety of targeted applications in food and pharmaceutical sectors.