Partial purification and characterization of polyphenol oxidase from Chinese parsley (Coriandrum sativum)

Rates of thermal degradation and isomerization of all-trans-β-carotenes in air and in triacylglycerols were determined. Degradation of carotenes in triacylglycerols was faster than that in air. The 13-cis-β-carotene level in triacylglycerols was higher than in air. Oxidized materials of triacylglycerols probably facilitated isomerization of carotenes and, thus, degradation. Amounts of all-trans-β-carotenes and all-trans-α-carotenes in pumpkin decreased with an increase in heating time. The proportion of 13-cis-β-carotene increased after heat treatment started, probably due to thermal isomerization of all-trans-β-carotenes to cis-isomers, and to decreases in amounts of all-trans-β-carotenes and all-trans-α-carotenes in pumpkin. Effects of heating methods on proportions of isomers; however, were not different.     

Effects of High-Pressure Processing with or without Blanching on the Antioxidant and Physicochemical Properties of Mango Pulp

The effects of high-pressure processing (HPP 300 MPa/15 min, 400 MPa/5 min, 500 MPa/2.5 min, and 600 MPa/1 min) and high-temperature/short-time processing (HTST 110 °C/8.6 s), with or without blanching, on mango pulp were comparatively evaluated in terms of the antioxidant compounds, antioxidant capacity, sugars, and color. Blanching treatment significantly increased the total phenol content and the antioxidant capacity of mango pulp, but did not change the levels of L-ascorbic acid, carotenoids, sugars, and visual color (total color difference, △E?<?2.00). Both HPP and HTST treatments significantly increased the total phenol content and antioxidant capacity of un-blanched mango pulp, but no significant changes occurred in the blanched mango pulp. HPP did not affect the levels of L-ascorbic acid, carotenoids, and sugars in mango pulp regardless of blanching. However, HTST significantly decreased the fructose and glucose levels, as well as induced the isomerization of β-carotene, with the increase in 13-cis-β-carotene accompanied by the decrease in all-trans-β-carotene. Moreover, HPP-treated mango pulp consistently showed lower △E values than those HTST-treated samples, regardless of blanching.     

Characterization of nutritionally important phytoconstituents in bitter melon (<Emphasis Type="Italic">Momordica charantia</Emphasis> L.) fruits by HPLC–DAD and GC–MS

Bitter melon (Momordica charantia L.) is the traditional vegetable used as medicinal food, in different parts of the world, including Korea and China. Little is known about its bioactive composition aside from its health-promoting properties. Therefore, the present work aimed to determine the content of carotenoids, tocopherols, folates and fatty acids in bitter melon fruits. Using HPLC–DAD, six major carotenoids were quantified in fruits; all-E-lutein was recorded in highest quantity, followed by all-E-β-carotene and α-carotene, with 79.5, 17.6 and 1.5 % of total carotenoids, respectively. A high content of α-tocopherol (42.93 μg/g FW) and total folate (0.724 µg/g FW) was also recorded in fruits using HPLC–DAD and microbiological assay, respectively. The total lipid content of 1.79 % was recorded in fresh fruits (FW). Using GC–MS, sixteen fatty acids were identified in lipid fraction; α-linolenic acid (ALA; C18:3) was found in highest quantity (44.33 %) followed by palmitic acid (C16:0) (29.64 %), and linoleic acid (C18:2) (10.32 %). Melon fruits contain a low amount of saturated fatty acid and high-mono and polyunsaturated fatty acids, in the form of ALA. Knowledge of bioactive composition in bitter melon fruit will be useful for proper diet recommendations and also for nutrient database updating.     

An approach for extraction,purification, characterization and quantitation of acylated-anthocyanins from <Emphasis Type="Italic">Nitraria tangutorun</Emphasis> Bobr. fruit

In the present study, a systematic approach for extraction, purification and analysis of acylated-anthocyanins from Nitraria tangutorun Bobr. fruit was explored. Six acylated-anthocyanins in N. tangutorun fruit were identified by HPLC-MS/MS, and a rapid and efficient HPLC-DAD method was developed to analyze the acylated-anthocyanins. Ultrasonic-assisted extraction conditions of acylated-anthocyanins were optimized using response surface methodology, extraction at 70 °C for 32 min using 70% methanol solution (0.1% HCl, v/v) rendered an extract with 80.37?±?2.66 mg/100 g of cyanidin-3-O-(trans-p-coumaroyl)-diglucoside and 97.88?±?4.06 mg/100 g of total acylated-anthocyanins. Nine macroporous resins were investigated for preliminary purification of acylated-anthocyanins. According to the static/dynamic adsorption and desorption tests, XDA-6 macroporous resin exhibited the maximum potential for preparing acylated-anthocyanins. The purity of cyanidin-3-O-(trans-p-coumaroyl)-diglucoside (43.30 mg/g) in purified acylated-anthocyanins was 201.89 times of that of the extract (0.21 mg/g), and the purity of total acylated-anthocyanins increased from 0.36 to 56.44 mg/g. Besides, the stability (t _1/2) of cyanidin-3-O-(trans-p-coumaroyl)-diglucoside and total acylated-anthocyanins increased by more than five-fold after purification using XDA-6. The established methods of analysis, extraction and purification of acylated-anthocyanins were hopefully utilized in food industry.     

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.     

Determination of carotenoids in Dunaliella salina cultivated in Taiwan and antioxidant capacity of the algal carotenoid extract

A simple HPLC method with good separation efficiency was developed to determine all-trans and cis forms of carotenoids in Dunaliella salina cultivated in Taiwan. The analysis used a C30 column (250 × 4.6 mm, 5 μm) and an isocratic solvent system (flow rate = 1 mL/min) mixing methanol–acetonitrile–water (84/14/2, v/v/v) and methylene chloride, (75/25, v/v). Carotenoids were detected at 450 nm. Moreover, the antioxidant capacities of the algal carotenoid extract were also evaluated with Trolox equivalent antioxidant capacity (TEAC) assay, reducing power and 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radical scavenging assay. Results showed that 7 carotenoids in the algal extract could be separated simultaneously within 30 min and the total amount of them was 290.77 mg/g algae. The contents of all-trans-β-carotene and 9- or 9′-cis-β-carotene, the major carotenoids in the algae, were 138.25 and 124.65 mg/g algae, respectively. The contents of all-trans-lutein, all-trans-zeaxanthin, 13- or 13′-cis-β-carotene, all-trans-α-carotene and 9- or 9′-cis-α-carotene were 6.55, 11.27, 4.95, 2.69, and 2.41 mg/g algae, respectively. The algal carotenoid extract had significantly higher antioxidant activity than all-trans forms of α-carotene, β-carotene, lutein and zeaxanthin in all antioxidant assays. The cis forms of carotenoids, especially 9- or 9′-cis-β-carotene, might play crucial roles for the antioxidant capacities of the algal extract.     

Thermal Isomerization and Degradation Behaviours of Carotenoids in Simulated Sweet Corn Juice

The thermal behaviour of carotenoids may affect the nutritional value and flavour quality of sweet corn juice. In this study, carotenoid compositions and volatile components in simulated sweet corn juice at elevated temperatures from 100 to 130 °C were identified and compared by C₃₀-HPLC-DAD-APCI-MS and HS-SPME-GC-MS methods. The result showed that with the increase of temperature, concentrations of total and trans carotenoids in sweet corn juice model decreased gradually, as compared with all-trans α-carotene and all-trans β-carotene, oxy carotenoids (such as all-trans lutein, all-trans zeaxanthin and all-trans β-cryptoxanthin degraded faster), especially for carotenoid epoxides (such as neoxanthin). Meanwhile, the concentration of total cis carotenoids was related with the formation of some oxidative products and volatile compounds. Levels of major volatile components derived from carotenoids in sweet corn juice model including 4-ethyltoluene, p-cymene, 2-ethyl-1, 4-dimethylbenzene, 1, 2, 3, 4-tetramethylbenzene, dodecane, BHT, 1,7-dimethyl naphthalene, hexanal, 2-nonenal, undecanal, benzaldehyde, geranyl acetone, etc. increased with temperature. Some new volatiles such as 1, 2, 4-trimethylbenzene, naphthalene, pentadecane, acetaldehyde, β-ionone, limonene, tridecanone, etc. were also formed under higher temperatures. It is suggested that the aromatic compounds containing benzene ring and alkane are produced by degradation of carotenoids, which affect the overall flavour of sweet corn juice.     

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.     

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.     

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.     

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.     

Characterization of nutritionally important phytoconstituents in minimally processed ready-to-eat baby-leaf vegetables using HPLC–DAD and GC–MS

Ready-to-eat baby-leaf vegetable market has been rapidly growing and offering to consumers convenient and appealing products, rich in health beneficial bioactive compounds. In the present study, the composition of carotenoids, tocopherols, and fatty acids were analyzed in seven baby-leaf vegetables using HPLC–DAD and GC–MS. Among the vegetables, the maximum amount (μg/g FW) of All-E-violaxanthin (42.77), 9′-Z-neoxanthin (22.13), All-E-lutein (69.67), All-E-β-carotene (60.18), total carotenoids (195.21), γ-tocopherol (19.68) and total tocopherol (47.68) were found in Batavian lettuce (Lactuca sativa L. var. Acephala). In all the studied baby-leaf vegetables, α-linolenic acid (ALA, C18:3) was found in highest quantity (44.73–54.39 %) followed by palmitic acid (C16:0) (13.02–19.49 %), and linoleic acid (C18:2) (8.25–21.54 %). Significantly high amount polyunsaturated fatty acids (PUFA) were recorded in Batavian lettuce (74.33 %) and red Romaine (72.72 %), compared to other studied vegetables. In view of health benefits, baby-leaf vegetables contain a low amount of saturated fatty acids and high-mono and PUFA, which can enhance the health benefits of these vegetables. Carotenoids in most of these studied baby-leaf vegetables can be classified as very high. Knowledge of carotenoid, tocopherols and fatty acids composition in different baby-leaf vegetables will be useful to nutritional experts for selection of nutrient-dense plants for food fortification and proper diet recommendation. To our knowledge, this is the first report on fatty acids composition from baby-leaf vegetables.     

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.     

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.     

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.     

A mathematical model for moisture movement during continous and intermittent drying of <Emphasis Type="Italic">Eucalyptus saligna</Emphasis>

A modified diffusion-based mathematical model is proposed to describe the moisture movement during continuous and intermittent drying of Eucalyptus saligna. This model includes the temperature change, the surface drying coefficient (β _n ) and 2 diffusion coefficients [from green to FSP (D _f ) and from FSP to dry condition (D _o )] as important parameters. The final model expression obtained was M?=?exp (??25 β _n ² D _t /l²) with the β _n used was 1.5807 kg m^?2 s^?1, the D _f was 2.26?×?10^?11 m² s^?1, and the D _o was 5.85?×?10^?12 m² s^?1. The range of temperature change between heating and non-heating phases in the intermittent drying regimes was from 24.9 to 31.8 °C. The R² values obtained when the model was fitted into the drying data of different intermittent regimes ranged from 71.5 to 85.9%. The R² value was 87.4% when the model was fitted into continuous trial data. The high values of R² indicate that the model can be used to understand the moisture reduction both in intermittent and continuous regimes.     

Mathematical quantification of total carotenoids in Sioma<Superscript>®</Superscript> oil using color coordinates and multiple linear regression during deep-frying simulations

Sioma^® is a variety of red palm oil produced in Ecuador; it is mainly unsaturated, has no flavor, odor, nor cholesterol, and it is GMO-free and free of trans fatty acids. The main objectives of this study were: (a) to study changes in fatty acids, color coordinates, total carotenoids and carotenoid composition during deep-frying simulations; (b) to develop a mathematical model that allows quantification of total carotenoids (antioxidant compounds) using routine color measurements. Two different deep-frying temperatures were assayed 180 and 240 °C. The main fatty acids and carotenoids found in this oil were: (a) oleic, palmitic, and linoleic acids, and (b) α-, β-, and δ-carotenes. During these deep-frying simulations, Sioma^® oil became lighter and more yellowish (L* and b* values increased) and more greenish (a* values decreased); these changes were more evident for higher temperatures. At 180 °C, total carotenoids decreased linearly, from almost 500 mg L^?1, at a rate of 5 mg /kg¹ min^?1; however, at 240 °C the degradation of carotenoids was almost complete after 40 min. Finally, the mathematical models developed using multiple linear regressions allowed an easy and fast quantification of total carotenoids using color measurements.     

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.