Isotope Internal Standard Method for Determination of Four Acrylamide Compounds in Food Contact Paper Products and Food Simulants by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

A new method was developed for the determination of four acrylamide compounds (acrylamide, methacrylamide, N-methylol acrylamide, N-(Methoxymethyl)methacrylamide) in food contact paper products, three kinds of water-based food simulants, and dry food simulant (modified polyphenylene oxide, MPPO) by using ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Acetonitrile was used as the extraction solvent for different kinds of samples. The extraction solution of paper products was purified with QuEChERS technology. Four analytes were separated by gradient elution in a UPLC HSS T3 column (100 mm?×?2.1 mm, 1.8 μm) with methanol and 0.1 % formic acid water as mobile phases, and then detected in electrospray ionization mode of MS/MS with multiple reaction monitoring (MRM). Under the optimal conditions, the calibration curves for four analytes were linear within the range of 1.0–200 μg/L and the correlation coefficients were higher than 0.998. The quantitation limits of the method (S/N?=?10) of four analytes were in the range of 0.3–20 μg/kg. The mean recoveries for five sample matrixes at three spiked concentration levels of 0.3–200 μg/kg were in the range of 81–108 % with the relative standard deviations (RSDs, n?=?6) values ranging from 2.5 to 7.1 %. The developed method is accurate, simple and rapid, which can be applied to the determination of acrylamide compounds in food contact paper products and food simulants.     

Simultaneous Analysis of Free/Bound Phytosterols and Diosgenin in Taiwanese Yams

Gas chromatography (GC) and high performance liquid chromatography (HPLC) methods were developed for the simultaneous analysis of phytosterols and diosgenin in two representative Taiwanese yams, Dioscorea pseudojaponica Yamamoto and Dioscorea alata L. The major phytosterols found were β-sitosterol, stigmasterol, and campesterol. GC afforded good separation of phytosterols and diosgenin, with the diosgenin peak appearing between stigmasterol and β-sitosterol. For HPLC, UV detection had higher sensitivity (detection limits 0.03–0.09 μg); however, evaporative light scattering detection (ELSD) achieved higher noise tolerance and did not show baseline interference from solvent gradients. In addition, mixed solvents for extraction before acid hydrolysis, which is necessary to avoid fibers and acid hydrolysates binding to the target compounds, were evaluated. Phytosterol contents of 30.1 and 9.9 mg/100 g were found in D. pseudojaponica Yamamoto and D. alata L., respectively. Diosgenin was only found in D. pseudojaponica Yamamoto at a content of 15.2 mg/100 g.     

Isotope Ratio Mass Spectrometry Coupled to Element Analyzer and Liquid Chromatography to Identify Commercial Honeys of Various Botanical Types

The aim of the present work was to investigate whether honeys of various botanical characteristics could be discriminated and identified on the basis of the isotopic data. For this purpose, 45 commercial honey samples of various botanical types were analyzed using isotope ratio mass spectrometry (IRMS) coupled to element analyzer (EA) and liquid chromatography (LC). δ ¹³C values of honey; corresponding extracted protein and individual sugars (sucrose, glucose, and fructose) of honey; reducing sugar; and sucrose contents were determined and utilized to demonstrate the authenticity of commercial honeys of different botanical types. Results indicated that a very strong correlation (δ ¹³C_protein = 0.862δ ¹³C_honey + 0.800, R ² = 0.944) was observed between δ ¹³C honey values and δ ¹³C protein values of real honey samples. δ ¹³C_honey and δ ¹³C_protein should range from ?27.2 to ?23.5 and ?26.9 to ?23.6‰ for pure honeys of various botanical types investigated in this study. The use of isotopic compositions and some systematic differences as authenticity criterion permits the honey samples of various botanical types to be reliably detected.     

Effect of heat-treated <Emphasis Type="Italic">Nuruk</Emphasis> on the quality characteristics of aged <Emphasis Type="Italic">Yakju</Emphasis>

Long-term aging of Yakju, a traditional Korean liquor made of rice and Nuruk (a fermentation agent), causes browning and odor and flavor development. This study investigated the effects of heat-treated Nuruk (50–80 °C, 30 min) on Yakju quality. The saccharogenic powers and glucoamylase, α-amylase, and carboxypeptidase activities were similar in non-heat-treated Nuruk and that treated at 50 °C. However, acidic protease and alcohol dehydrogenase decreased above 50 °C. The content of nitrogen-containing compounds was inversely proportional to the heat-treatment temperature. Compounds that cause off-flavors decreased at 50–60 °C, but increased at 70–80 °C, whereas compounds that provide fragrance increased at 50–60 °C. Sensory evaluation indicated that bad taste attributes were higher in Yakju produced using non-heat-treated Nuruk. Therefore, heat treatment of Nuruk at 50 °C can be adopted as a method for improving Yakju quality, as enzymatic activities that affect color, aroma, and taste are regulated.     

Characterization of aromatic compounds and biological activities of essential oils from Tunisian aromatic plants

The aromatic compounds and biological activities of essential oils from six Tunisian aromatic plants including Artemisia herba-alba, Rosmarinus officinalis, Thymus capitatus, Mentha piperita, Ocimum basilicum and Artemisia absinthium were investigated. Hydro-distillation was used to extract essential oil from these plants. The identification of compounds from essential oils was performed using GC–MS analysis. Camphor (28.47%) was the major compound of A. absinthium essential oil. High contents of verbenone (20.99%) and camphor (19.72%) were found in R. officinalis. In the case of T. capitatus, carvacrol (81.09%), gamma terpinene (6.61%) and caryophyllene (4.87%) were identified as the major compounds. While eugenol (24.69%), linalool (18.00%) were characteristic compounds of O. basilicum essential oil, camphor (39.10%) and farnesol (14.25%) together with bornyl acetate (12.31%) were the main constituents of A. absinthium. These oils were also subjected to a screening for their antioxidant activity and essential oil from A. absinthium showed a greater antioxidant activity (IC₅₀?=?0.0063 mg/mL) compared to the standard Vitamin E (IC₅₀?=?0.019 mg/mL). The antibacterial activities of the oils against seven pathogenic strains, Pseudomonas aeruginosa, Bacillus cereus, Salmonella, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis and Micrococcus luteus, were tested. The highest and broadest activity was shown by M. piperita; however, Ocimum basilicum was inactive against all strains. Essential oils were also evaluated for antidiabetic and anti-acetylcholinesterase activities. The IC₅₀ values of A. herba-alba and O. basilicum against α-amylase were respectively 17.76 and 16.32 µg/mL suggesting a powerful anti-diabetic effect comparable to that of acarbose (IC₅₀?=?14.88 µg/mL). R. officinalis, M. piperita and A. absinthium exhibited an interesting acetylcholinesterase inhibition with IC₅₀ equal to 22, 24 and 58 µg/mL respectively.     

A comparative study on cytotoxicity and antiproliferative activities of crude extracts and fractions from Iranian wild-growing and cultivated <Emphasis Type="Italic">Agaricus</Emphasis> spp.

Little is known about anticancer capability of wild-growing mushrooms belonging to Agaricus spp. in comparison with their cultivated counterparts. The present study was done to evaluate in vitro antiproliferative effects of dichloromethane-methanol (1:1, v/v) extracts obtained from several Iranian wild strains of Agaricus spp. in comparison with the cultivated white button mushroom, A. bisporus. The wild brown A. bisporus at 500 µg/mL moderately prevented the growth of human prostate cancer (PC3) and human breast cancer (MCF-7) cell lines by 23.54 and 24.57%, respectively, while the wild strains of A. devniensis and A. gennadii at 500 µg/mL had only marginal inhibitory effects. On the contrary, the cultivated A. bisporus significantly inhibited the cell growth at concentrations as low as 125 µg/mL (p?<?0.05). Further, seven distinct fractions were determined based on thin layer chromatography analysis of the cultivated A. bisporus extract. The only active fraction was found to be eluted by petroleum ether (PE):ethyl acetate (EtOAc) (3:2 v/v) which prevented the growth of MCF-7 and PC3 by 74.00 and 63.5%, respectively at 500 µg/mL. Besides, the fraction imposed obvious cytopathic effects in both cell lines at all the tested concentrations, starting from 125 µg/mL. The findings of this study may validate that the known antioxidant potency of wild Agaricus spp. would not necessarily be correlated to their anticancer activity. This research further validated that some semi-polar antiproliferative compounds could be present in the PE/EtOAc-fraction of the cultivated white button mushroom, which warrants further investigations.     

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.     

Antioxidant Activity and Determination of Phenolic Compounds from <Emphasis Type="Italic">Eugenia involucrata</Emphasis> DC. Fruits by UHPLC-MS/MS

Fruits have been the focus of several studies aimed at finding new antioxidant sources for protection against the damage caused by reactive species. In this study, the antioxidant activity and the presence of phenolic compounds in all parts (peel, pulp, and seeds) of Eugenia involucrata DC. fruits were evaluated. DPPH^·, ABTS^·+, and ORAC methods were used to determine the antioxidant activity, and an UHPLC-MS/MS method was developed for determining the phenolic compounds (gallic, chlorogenic, ferulic, p-coumaric and ellagic acids, quercetin, and myricetin). In the determination of both antioxidant activity and phenolic composition, the efficiency of solvents with different polarities—methanol/H₂O (80:20, v/v), ethanol/H₂O (80:20, v/v), methanol/acidified water with phosphoric acid pH 3.00 (80:20, v/v), and ethyl acetate—for the extraction of the phenolic compounds, was also evaluated. All parts of E. involucrata fruits showed antioxidant activity, in the range of 36.68 ± 1.44 to 873.87 ± 18.24 μmol TE g^?1, being the highest values found in the seeds and peel when more polar extraction solvents were used. Six, five, and three phenolic compounds were identified and quantified in the pulp, peel, and seeds, respectively, with the highest abundance as p-coumaric acid (14 ± 2 mg kg^?1) in the pulp, quercetin (47 ± 5 mg kg^?1) in the peel, and gallic acid (74 ± 4 mg kg^?1) in the seeds, also when more polar solvents were used. Although antioxidant activity methods suggested that the peel and seeds have more antioxidant potential, a wider variety of compounds were determined in the pulp.     

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.     

Combined Application of Fluorescence Spectroscopy and Chemometrics Analysis in Oxidative Deterioration of Edible Oils

Combined methods of fluorescence spectrometry with chemometrics were used to monitor oxidation deterioration of edible oil. Synchronous and three dimensional fluorescence spectroscopy techniques were proposed for monitoring palm oil, camellia oil, sunflower oil and perilla oil during oven accelerated oxidation. Principal component analysis plot of fluorescence intensity (λex = 320–700 nm) clearly showed oxidative evolution of oils over heating time. High saturated or monounsaturated oils exhibited high regression coefficients between peroxide values and fluorescence intensity (R ²  = 0.973 for 400 nm in palm oil; R ²  = 0.956 for 370 nm in camellia oil). High diunsaturated oil exhibited high regression coefficient between nonpolar carbonyl compounds and fluorescence intensity (R ²  = 0.970 for 370 nm in sunflower oil). High triunsaturated oil exhibited high regression coefficient between p-anisidine value and fluorescence intensity (R ²  = 0.938 for 665 nm in perilla oil). In conclusion, Fluorescence spectroscopy is a rapid and green nondestructive method for oxidation monitoring. Differences of fatty acid compositions played key rules in formation of oxidation products and evolution of fluorescence spectra.     

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.     

Determination of 13 Phenolic Compounds in Rice Wine by High-Performance Liquid Chromatography

Rice wines are widely consumed by the general public in Asian countries, while comprehensive studies focused on the individual phenolic compounds in rice wines are limited. A rapid method for simultaneous determination of 13 phenolic compounds in rice wines by high-performance liquid chromatography (HPLC) was developed and validated, and the phenolic compounds in commercial rice wine samples (Chinese rice wine, Japanese sake, and Korean makgeolli) were determined in this paper. The identified compounds contained gallic acid (GA), protocatechuic acid (PRCA), vanillic acid (VA), syringic acid (SRA), caffeic acid (CA), ferulic acid (FA), p-coumaric acid (pCA), sinapic acid (SA), chlorogenic acid (CHA), (+)-catechin (CAT), (?)-epicatechin (EPI), quercetin (QUE), and rutin (RUT). Phenolics were separated with a C18 reversed-phase column at 38 °C by gradient elution using 3 % acetic acid aqueous solution (solvent A) and acetonitrile (solvent B) (0 min, 5 % B; 5 min, 8 % B; 10 min, 15 % B; 20 min, 25 % B; and 25 min, 5 % B) as the mobile phase at 280 nm with flow rate of 1.0 mL min^?1. With direct injection of rice wine samples, the chromatograms of all analytes were observed within 20 min, all calibration curves were linear (R ²?>?0.995) within the range, limits of detection (LOD) ranged from 0.02 to 0.06 μg mL^?1, and good recoveries (88.07–106.80 %) and precision (relative standard deviation (RSD)?<?5.36 % ) were obtained for all compounds. This method was applied to quantify phenolic compounds in commercial rice wine samples (Chinese rice wine, Japanese sake, and Korean makgeolli), and good separation peaks were observed and catechin was the predominant phenolic in the samples. The average values of total phenolic contents of the three groups of rice wine were significantly different (p?<?0.01). In conclusion, this procedure can be used to determine the phenolic compounds in various types of rice wines, as well as to characterize and differentiate rice wine samples.     

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.     

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.     

Simultaneous Identification of Different Domains of Calpain from Blood and Turkey Meat Samples Using Casein Zymography

The aim of this study was to develop a simple method for simultaneous identification of two different domains of calpains (μ- and m-calpains) in blood and turkey meat samples. The method is based on Tris-based extraction techniques followed by casein zymography detection. The extracts were purified by dialysis, and target compounds were separated on Diethylaminoethyl (DEAE)-Sephacel anion-exchange chromatography. Results indicated that a buffer pH of 6.7 produced optimum extraction efficiency. The separation of calpastatin, μ- and m-calpains on column chromatography was carried out using stepwise elution profiles of 100, 200, and 400 mM NaCl solutions, respectively. Casein zymography study clearly demonstrated the presence of μ- and m-calpains in the crude extracts of breast and blood samples; however, μ-calpain was absent in the thigh sample. Similarly, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis identified both the calpains from muscle and blood samples, but presence of calpastatin was observed in both the breast and thigh muscle samples only. The activity analysis of purified fractions indicated that both the μ- and m-calpain concentrations were differed significantly (P?<?0.05) amongst breast, thigh and blood samples. Collectively, it was concluded that Tris buffer (pH 6.7) and DEAE-Sephacel column for extraction and separation of μ- and m-calpains and casein zymography and SDS-PAGE detection methods were most suitable for accurate identification of calpains and calpastatin from blood and turkey meat samples.     

Smart NMR Method of Measurement of Moisture Content of Vegetables During Microwave Vacuum Drying

Microwave drying is usually combined with vacuum environment in conjunction with hot air flow to draw the moisture rapidly. The moisture content of the vegetables undergoing drying is hard to measure online. This research designed a microwave vacuum drying (MVD)-low-field nuclear magnetic resonance (NMR) smart device and investigated the feasibility of NMR method for online measurement of state of moisture during MVD. The relation between the signal amplitude (A ₂) and the true moisture content (M ₁) of six kinds of vegetables (mushroom, carrot, potato, lotus, edamame, vegetable corn) was fitted to estimate if NMR can measure the M ₁ of vegetables directly. Results showed that A ₂ and M ₁ of different fresh vegetables had no single empirical mathematical model to fit. However, for each kind of these vegetables, the A ₂ and corresponding M ₁ in different MVD stages showed a significant linear relationship. The predicted moisture content (M ₂) of mushroom: M ₂ = 5.25351 × 10^?4 A ₂ ? 0.34042, R = 0.996; carrot: M ₂ = 5.78756 × 10^?4 A ₂ ? 0.14108, R = 0.998; potato: M ₂ = 3.10019 × 10^?4 A ₂ ? 0.10612, R = 0.991; lotus: M ₂ = 2.32415 × 10^?4 A ₂ ? 0.01573, R = 0.998; edamame: M ₂ = 3.13310 × 10^?4 A ₂ ? 0.4198, R = 0.996; vegetable corn: M ₂ = 1.69461 × 10^?4 A ₂ ? 0.09063, R = 0.995. The linear models between M ₂ and A ₂ were able to estimate the end point (M ₁ < 8%) of MVD with a high accuracy (P > 0.950).     

LC-ESI-MS/MS Analysis and Extraction Method of Phenolic Acids from Gluten-Free Precooked Buckwheat Pasta

In many countries, common buckwheat (Fagopyrum esculentum Möench) has been cultivated for its nutritive value as food ingredient. This plant is a rich source of vitamins and exogenic amino acids. Many of the health-promoting effects of F. esculentum have been attributed to a large amount of phenolic compounds. Presented in this paper, precooked buckwheat pasta, produced by extrusion cooking, is a gluten-free product without any technological additives. Moreover, it contains natural polyphenolic antioxidants and therefore could be classified as convenience food. The phenolic acid compositions of precooked buckwheat pasta were as follows: gallic, protocatechuic, gentisic, 4-OH-benzoic, vanillic, trans-caffeic, cis-caffeic, trans-p-coumaric, cis-p-coumaric, trans-ferulic, cis-ferulic, and salicylic. A very important step of sample pretreatment before quantitative analysis is the choice of extraction conditions. Therefore, in this study, before quantitative analysis (liquid chromatography-mass spectrometry, LC-ESI-MS/MS), optimization of ultrasound-assisted extraction (UAE) of phenolic acids from precooked buckwheat pasta was performed. The most effective conditions for the isolation of phenolic acids from precooked buckwheat pasta with the use of UAE were as follows: 80 % aqueous ethanol, 60 °C, ultrasound frequency 20 kHz, power 100 W, and time 40 min.     

TLC-Digital Image-Based Fluorometric Analysis of Ergosterol and Chitin Content in Food Grains Artificially Infested with <Emphasis Type="Italic">Aspergillus flavus</Emphasis> and <Emphasis Type="Italic">Fusarium verticillioides</Emphasis>

Novel thin-layer chromatography-digital image-based analytical methods were developed for the quantitation of ergosterol and chitin content in six food matrices (rice, wheat, maize, sorghum, groundnut, and sunflower), artificially infested with Aspergillus flavus (MTCC 6513)/Fusarium verticillioides (MRC 826). For ergosterol, single-step method, based on liquid/liquid extraction, was followed by thin-layer chromatography (TLC). Chitin was solubilized using lithium chloride (5%) in dimethyl acetamide and converted to chitosan using 5 N NaOH and subsequently complexed with calcofluor white dye. The absorption and emission maxima of chitosan-calcofluor complex were recorded at λ 350/230 and 430 nm, respectively. The sensitivity based on the limit of detection (LOD) was found to be 100 ng both for ergosterol and chitin analysis. Based on ergosterol and chitin analysis, groundnut and maize were found to be suitable substrates for A. flavus (p?<?0.013 and p?<?0.01), while sorghum followed by groundnut and sunflower were found to be ideal for F. verticillioides (p?<?0.01 and p?<?0.0001) and rice was established as poor substrate as there was no growth on it up to 12 days of incubation. A strong correlation was found between ergosterol and chitin contents with regression (r ²) values of 0.974 and 0.997 in food grains inoculated with A. flavus and F. verticillioides, respectively, during the period of infection. The authenticity of the two methods developed was further confirmed by applying them to commercial food grains and flours. Thus, ergosterol in combination with chitin analysis could be successfully used as an index of fungal contamination employing TLC-digital-based analytical methods.     

Influence of additives on dough rheology and quality of <Emphasis Type="Italic">Thepla</Emphasis>: an Indian unleavened flatbread

Thepla is Indian unleavened flatbread made from whole-wheat flour with added spices and vegetables. In the present study, effect of addition of various emulsifiers such as sodium stearoyl-2-lactylate (SSL), di acetyl tartaric acid ester of monoglyceride (DATEM) and glycerol mono-stearate (GMS) were studied. Further hydrocolloids (guar gum, carrageenan) and modified polysaccharides [hydroxypropyl methylcellulose (HPMC) and carboxymethyl cellulose] were added at the concentration ranging from 0.25 to 1 % on the basis of whole wheat flour to prepared the doughs. These thepla doughs were analyzed for rheology and theplas were analyzed for tear force. Additives helped in improvement of dough and thepla quality. Guar gum increased dough stickiness and strength to the highest (31.12 and 1.76 g respectively). Also, guar gum decreased tear force value of thepla to 208.4 g. Tear force was found to be increasing with the duration of storage. Highest improvement in thepla dough and quality was obtained by the addition of guar gum at 0.75 % which retained the softest texture of thepla.     

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.