Publication year: 2012
Source: Food Chemistry, Available online 2 February 2012

Emese Kápolna, Kristian H. Laursen, Søren Husted, Erik H. Larsen

The aims were to bio-fortify onions by foliar application of selenium (Se) and to intrinsically label bioactive Se-metabolites in onion and carrot by enriched, stableSe for use in human physiological studies. Onion bulbs and leaves were enriched in Se by repeated foliar spraying of 10 or 100 μg Se mlsolutions of sodium selenite (Se(IV)) or sodium selenate (Se(VI)). ICP-MS analysis of onion leaves and bulbs showed that the Se concentration was enhanced by up to a factor of approximately 50 and 200 in bulbs and leaves, respectively. HPLC-ICP-MS analysis of proteolytic plant extracts showed that foliar application of Se(IV) gave rise to bio-synthesis of a higher fraction of the desired organic Se species and was better tolerated by the plants than Se(VI). Based on these findings onions and carrots were bio-fortified by foliar application of a solution ofSe(IV) that was enriched to 99,7% asSe. TheSe- labeled metabolites in onions were predominantly γ-glutamyl-Se-selenomethyl-selenocysteine (γ-glu-MeSeCys),Se-methylselenocysteine (MeSeCys) andSe-selenomethionine (SeMet). Furthermore, we report here for the first time the finding in carrots of the bioactive MeSeCys, the identity of which was verified by HPLC-ESI-MS/MS.

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Publication year: 2012
Source: Food Chemistry, Available online 2 February 2012

W. Meier-Augenstein, H.F. Kemp, S.M.L. Hardie

Neat Scottish whiskies and the local source water used for and during whisky production have been analyzed for theirH andO isotopic composition by High Temperature Conversion – Isotope Ratio Mass Spectrometry (TC/EA-IRMS). With coefficients of determination Rfor δH and δO of 0.71 and 0.88, respectively, measured δH and δO values for water used in the production of Scottish Whisky were found to be well correlated with the δH and δO values observed for the corresponding whiskies. By plotting bulkH against bulkO isotope abundance data of authentic whisky and counterfeit whisky samples it was possible to discriminate between samples of authentic whisky and samples of counterfeit whisky.

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Publication year: 2012
Source: Food Chemistry, Available online 2 February 2012

Chandra mohan Chithra, Halagowder Devaraj

Screening of crustacean proteins in relation to molting cycle revealed a 48kDa protein which is cross reactive to Gas7 antibody and expressed predominantly in the intermolt stage where the cells remain quiescent. This 48kDa protein ofPenaeus monodonhas been purified to homogeneity using ammonium sulphate precipitation, ion-exchange chromatography and electro elution. MALDI-TOF analysis of the purified protein revealed the presence of ANK repeat and LEM domain regions homologous to those of mouse. RT-PCR revealed 684bp in all molting stages with varied expression. Bioinformatic analysis showed that the ankyrin repeat domain in the 48kDa protein ofP. monodonis highly conserved amongH. sapiens, M. musculus, R. rattus, D. rerioandD. mojavensis.Secondary structure prediction revealed a commonly conserved region between mouse Gas7 and the ANK repeat region ofP. monodon.Thus, we concluded that the isolated 48kDa protein fromP. monodonis a novel, Gas7-like protein with ANK repeat and LEM domain involved in molting.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 2 February 2012

Jiansheng Wang, Honghui Gu, Huifang Yu, Zhenqing Zhao, Xiaoguang Sheng, ...

Five main cultivars from China and 143 parent materials grown in a greenhouse were used to investigate the glucosinolates in broccoli florets. Eight aliphatic glucosinolates, four indole glucosinolates, and one aromatic glucosinolate were identified and quantified using high-performance liquid chromatography (HPLC). The results showed that glucoraphanin, glucobrassicin, 4-methoxyglucobrassicin and neoglucobrassicin were present in all samples. However, the predominant type of glucosinolate was different among pure lines. The anti-cancer glucoraphanin concentration ranged from 0.06 to 24.17 μmol/g in pure lines and from 1.57 to 5.95 μmol/g in commercial cultivars. The progoitrin concentration in commercial cultivars varied from 1.77 to 6.07 μmol/g with a mean value of 3.20 μmol/g. Significant variations were observed in the concentration of individual glucosinolates and in each class of glucosinolates among broccoli populations. Dozens of specific lines with altered glucosinolate profiles, as well as ten good candidates for breeding high-chemoprotective glucosinolate cultivars, were obtained according to the putative glucosinolate pathway in broccoli.

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Publication year: 2012
Source: Food Chemistry, Available online 2 February 2012

Hye Hyun Yoo, Jeong Hill Park

Ginsenosides, from heat-processed ginseng, and sapogenins were evaluated for their inhibitory effects on the enzyme catalytic activities of cyclooxygenases-1 and -2 (COX-1 and -2). The ginsenosides, 20(S)-Rg3, Rg5, and Rk1, inhibited COX-2 activity, but did not affect the enzyme activity of COX-1. Protopanaxatriol (PPT) moderately inhibited both COX-1 and -2. The ginsenosides, 20(R)-Rg3, Re, and protopanaxadiol (PPD) showed a minimal effect on COX-1 and -2 activities. Taken together, ginsenosides Rg3(20S-form), Rg5and Rk1showed selective inhibitory activity on COX-2 by behaving as an inhibitor of the enzyme-substrate reaction.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 1 February 2012

Po-Shun Chuang, Meng-I Chen, Jen-Chieh Shiao

Tuna arehighly priced fishes that areoften usedin processed products. For effective fishery management and protection of consumers’ rights, it is important to develop a molecular method to identify the species of the tuna products. In this study we have developed a molecular method based on real-time polymerase chain reaction (real-time PCR) technology for the rapid identification of four tuna species. Four species-specific TaqMan probes were designedto identify bigeye tuna (Thunnusobesus), Pacific bluefin tuna (T.orientalis), southern bluefin tuna (T.maccoyii), and yellowfin tuna (T.albacares). A SYBR green system was also designedto enhance the authentication ofT. obesus. Both systems can distinguish target species from others in an efficient and high-throughput manner and can be applied to species identification of tuna products.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 1 February 2012

Ahmed Al-Souti, Jamal Al-Sabahi, Bassam Soussi, Stephen Goddard

Juvenile, red hybrid tilapia were fed diets containing cod liver oil (0, 4, 8, 12% of total diet) substituted against corn oil. After 10 weeks, no significant differences between treatments were seen in weight gain, specific growth rate, feed conversion ratio, whole body or dorsal muscle (fillet) proximate composition. Gas chromatography revealed significant differences in the total n-3 content and fatty acid profiles of dorsal muscle. The total n-3 content of dorsal muscle increased from 7.6 to 18.6%, total n-6 content fell from 37.5% to 12.9% and docosahexanaenoic acid increased from 5.8 - 16.1% of total fatty acids, in fish fed 0% and 12% fish oil, respectively. The retention of eicosapentaenoic acid was low in all dietary groups, possibly indicating selective use as a substrate for β-oxidation. The results demonstrate the potential to enhance the total n-3 fatty acids and docosahexaenoic acid in tilapia fillets by increasing dietary fish oil.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 1 February 2012

Federica Pasini, Vito Verardo, Maria Fiorenza Caboni, Luigi Filippo D’Antuono

The glucosinolate and phenolic profiles of 37 rocket salad accessions (32Eruca sativaand 5Diplotaxis tenuifolia) were obtained by liquid chromatography–mass spectrometry. Eleven desulpho-glucosinolates (DS-GLSs) were isolated and the glucosinolate profiles did not differ between the two species. Total DS-GLS content, expressed as sinigrin equivalents (SE) revealed a certain variability, ranging from 0.76 to 2.46 g kgd.w. but, again, the quantitative analysis did not discriminatesErucafromDiplotaxis. The polyphenol evaluation by HPLC-DAD-MS allowed the identification of two different classes of compounds in the two rocket salad species. Qualitative differences were observed between the polyphenol profiles at specific level: quercetin derivatives were the main phenolics ofDiplotaxis, whereas kaempferol derivatives characterisedErucasamples. The contents of total flavonoids determined as rutin equivalents (RE) ranged from 4.68 to 31.39 g kgd.w. Kaempferol-3,4’-diglucoside (71.4-82.2%) and isorhamnetin-3,4’-di-glucoside (7.8-18.4%) were always isolated as first and second more abundant phenolic compounds inErucasamples. No marker phenolic compounds were isolated inDiplotaxissamples.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 1 February 2012

Iqbal Ahmad, João P. Coelho, Iram Mohmood, Naser A. Anjum, Mário Pacheco, ...

The present study, carried out in a mercury (Hg) contaminated estuary, aimed to investigate: (i) the long-term evolution of the Hg bioavailability in the environmental matrices, in a period of 5 years (2003-2008), without new anthropogenic inputs; ii) the temporal evolution of Hg load (organic and inorganic forms) in the native bivalveScrobicularia plana, inferring the progression of human health risk associated to its consumption and the dependence on the animals’ size. The area selected was Laranjo basin of Ria de Aveiro (Portugal), where a Hg gradient was identified because of past discharges from a chlor-alkali plant. Two sites termed M (moderately contaminated) and H (highly contaminated) were compared with an uncontaminated reference (R) site. Results displayed a persistence of Hg in the environment, though the levels in sediment decreased at site H, confirming the ecosystem recovery. The risk associated to clam consumption remained stable in 2008 considering their total Hg (T-Hg) load and the limits established by public health authorities, though T-Hg levels significantly decreased at H site for size classes C3 (2 year) and C4 (4 year). Organic Hg (O-Hg) accumulation increased from 2003 to 2008, reaching threatening levels and suggesting an increased bioavailability of this Hg form. This evolution towards an increase of O-Hg accumulation was particularly prominent under a moderate contamination scenario (site M). Overall, it was demonstrated that a period of 5 years of ecosystem recovery was not enough to eliminate the risk to human consumers, highlighting Hg contamination in estuaries as a long-lasting legacy. Paradoxically, it was pointed out that in a given step of the long-term restoration process, occurring naturally in aquatic systems, the risk associated to bivalves’ consumption can appear augmented due to O-Hg accumulation increments.

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Publication year: 2012
Source: Food Chemistry, Available online 1 February 2012

Fatma Kayaci, Tamer Uyar

We produced functional nanowebs, containing vanillin, having prolonged shelf-life and high temperature stability facilitated by cyclodextrin (CD) inclusion complexation. Polyvinyl alcohol (PVA) nanowebs incorporating vanillin/cyclodextrin inclusion complex (vanillin/CD-IC) were produced via electrospinning technique. The vanillin/CD-IC was prepared with three types of CDs; α-CD, β-CD and γ-CD to find out the most favourable CD type for the stabilization of vanillin. PVA/vanillin/CD-IC nanofibres, having fibre diameters around ∼200 nm, were successfully electrospun from aqueous mixture of PVA and vanillin/CD-IC. Our results indicated that vanillin with enhanced durability and high temperature stability was achieved for PVA/vanillin/CD-IC nanowebs due to complexation of vanillin with CD, whereas the PVA nanofibres without CD-IC could not effectively preserve the vanillin. Additionally, we observed that PVA/vanillin/γ-CD-IC nanoweb was more effective for the stabilization and slow release of vanillin suggesting that the strength of interaction between vanillin and the γ-CD cavity is stronger when compared to α-CD and β-CD.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 1 February 2012

R. Song, D. Kelman, K.L. Johns, A.D. Wright

This study showed the relationship between tea leaf age, bud and first two leaves, and shade levels, on the relative concentrations of six major compounds of tea leaf, namely L-theanine, caffeine, and the major tea catechins; (–)-epigallocatechin gallate (EGCG), (–)-epigallocatechin (EGC), (–)-epicatechin (EC), and (–)-epicatechin gallate (ECG), all of which are reported to have positive effects on human health, as well as at the ferric reducing antioxidant power of bud and leaf extracts. The concentration of L-theanine and caffeine decreased as leaf age increased moving from bud to first and then second leaf, while the concentration of the four catechins increased from the bud to first and second leaves. In most cases this increase was generally relatively small but in the case of EGC it was seven to ten-fold. Certain chemical components of freshly picked, minimally processed and essentially unoxidised tea may potentially be used as markers for age, quality, authenticity and area of growth.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 1 February 2012

Joana Costa, Isabel Mafra, M. Beatriz P.P. Oliveira

Almond is responsible for trigging adverse immune responses in allergic individuals, and since it is present in many processed food, it is considered as a potential hidden allergen. Here we propose a novel, simple and highly specific approach to detect almond in a wide range of processed foods. The method consists of a real-time PCR assay targeting the gene encoding for the Pru du 5 allergen in almond, using the fluorescent Evagreendye combined with high resolution melting (HRM) analysis. The new approach allowed the detection of trace amounts of almond down to the level of 0.005% (w/w) and was successfully applied to processed foods. HRM analysis increased the specificity of the assay and was effective in distinguishing almonds from other plant foods, including the closely related fruits from the Rosaceae family. It was demonstrated for the first time that HRM analysis can provide a powerful tool for the identification of allergens in foods.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

Simon A. Haughey, Stewart F. Graham, Emmanuelle Cancouet, Christopher T. Elliott

Soya bean products are used widely in the animal feed industry as a protein based feed ingredient and have been found to be adulterated with melamine. This was highlighted in the Chinese scandal of 2008. Dehulled soya (GM & non-GM), soya hulls and toasted soya were contaminated with melamine and spectra were generated using near infrared reflectance spectroscopy (NIRS). By applying chemometrics to the spectral data, excellent calibration models and prediction statistics were obtained. The coefficients of determination (R) were found to be 0.89-0.99 depending on the mathematical algorithm used, the data pre-processing applied and the sample type used. The corresponding values for the root mean square error of calibration and prediction were found to be 0.081-0.276% and 0.134-0.0.368% respectively, again depending on the chemometric treatment applied to the data and sample type. In addition, adopting a qualitative approach with the spectral data and applying PCA, it was possible to discriminate between the four samples types and also, by generation of Cooman’s plots, possible to distinguish between adulterated and non-adulterated samples.

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Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

John W. Holland, Rajesh Gupta, Hilton C. Deeth, Paul F. Alewood

Milk proteins are susceptible to chemical changes during processing and storage. We used proteomic tools to analyse bovine αS1-casein in UHT milk. 2-D gels of freshly processed milk αS1-casein was presented as 5 or more spots due to genetic polymorphism and variable phosphorylation. MS analysis after phosphopeptide enrichment allowed discrimination between phosphorylation states and genetic variants. We identified a new alternatively-spliced isoform with a deletion of exon 17, producing a new C-terminal sequence, KSQVNSEGLHSYGL, with a novel phosphorylation site at S. Storage of UHT milk at elevated temperatures produced additional, more acidic αS1-casein spots on the gels and decreased the resolution of minor forms. MS analysis indicated that non-enzymatic deamidation and loss of the N-terminal dipeptide were the major contributors to the changing spot pattern. These results highlight the important role of storage temperature in the stability of milk proteins and the utility of proteomic techniques for analysis of proteins in food.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

Sirma Yegin, Yekta Goksungur, Marcelo Fernandez-Lahore

An extracellular aspartyl proteinase fromMucor mucedoDSM 809 submerged cultures was purified by a two-steps chromatographic procedure. The enzyme had a molecular weight (MW) of 32.7 kDa, and an isoelectric point (pI) value of 4.29; no evidence ofN-linked glycosylation was found. As judged by mass spectrometry, the primary structure of theM.mucedoenzyme presented homology withRhizopusspp. proteinases. The secondary structure showed 4% -helix, 48% -sheet and 48% random coil structure in 20 mM phosphate buffer (pH 5.8), as evidenced by circular dichroism spectroscopy. When acting on milk to provoke curd formation, the proteinase showed maximum potency at pH 5.0 and at 40°C. The enzyme was heat-sensitive and became completely inactivated after incubation at 55°C for 10 min. These results indicate that the milk-clotting enzyme fromM.mucedocan be considered as a potential substitute for bovine chymosin in cheese manufacturing.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

Stefanie Sandgruber, Andrea Buettner

Three different commercial encapsulated fish oil supplements were evaluated by orthonasal sensory evaluation of the encapsulated oil samples, and were rated according to characteristic odour qualities and hedonic impact. The potent odorants of the fish oil samples were obtained by solvent extraction followed by high vacuum transfer of the volatiles, and were evaluated by means of high resolution gas chromatography-olfactometry (HRGC-O). Comparative aroma extract dilution analysis of the solvent extract samples revealed 40 odorants. Most of these were identified based on their respective retention indices on two capillaries of different polarities, their mass spectral data, as well as their odour characteristics during HRGC-O, in comparison with the respective reference compounds. Thereby (poly)unsaturated fatty acid oxidation products were demonstrated to play a significant role in the volatile fraction of the fish oil supplements. Quantification of selected oxidation marker substances confirmed predominant presence of these compounds in the investigated samples, but also major quantitative differences between samples with regard to specific compounds. These data may be used as the basis for future evaluation of sensory quality of encapsulated fish oil supplements, and might relate to the degree of acceptance or rejection by the mothers being supplemented with the respective products.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

Paul Bendig, Lisa Maier, Walter Vetter

In North America brominated vegetable oil (BVO) is frequently used as a clouding agent for soft drinks. BVO containing soft drinks have a market share of about 15% in the USA. In our study we analyzed several soft drinks from North America for BVO and calculated exposures from our results and consumption data. Based on a mean content of 8 ppm in BVO-containing soft drinks, the average daily intake of BVO exceeds the intake of other organobromine compounds, e.g. polybrominated diphenyl ethers (PBDEs), by >4,000 times for adults and >1,000 times for children. By comparing the patterns of the brominated fatty acids (BFA) in the soft drinks, we were able to distinguish three BVO products used by three soft drink manufacturers. The analysis also revealed that the predominant BFAs in BVO are the Br2-18:0 (bromination product of oleic acid) and Br4-18:0 (bromination product of linoleic acid).

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

A.K. Biswas, M.K. Chatli, J. Sahoo

The aim of this study was to investigate the antioxidant activity of different solvent extracts of curry and mint leaf and their effect on color and oxidative stability of raw ground pork meat stored at 4±1 °C. The results indicated that among the two individual leaf categories, the ethanol extract of curry leaf (EHEC) and the water extract of mint leaf (WEM) showed higher DPPH and ABTSactivity. EHEC also exhibited the highest total phenolic contents while these were the lowest for WEM. WEM showed the highest superoxide anionic scavenging activity (%). The pork meat samples treated with EHEC and WEM showed a decrease in the HunterL-anda-values and a increase inb-value during storage at 4 °C. However, the pH and TBARS values were higher in control samples irrespective of storage periods. In conclusion, EHEC and WEM have the potential to be used as natural antioxidants to minimize lipid oxidation of pork products.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

Shih-Ying Yang, Shan-Yuan Tsai, Yu-Chi Hou, Pei-Dawn Lee Chao

Resveratrol has been reported to show various beneficial pharmacological effects. Nowadays, resveratrol dietary supplement (RDS) is available in the market. Cyclosporin (CsA), a probe drug of P-glycoprotein (P-gp) and cytochrome P450 3A4 (CYP3A4), is an important immunosuppressant. This study investigated the effect of coadministration of RDS on CsA pharmacokinetics.Rats were orally administered CsA alone and coadministered with RDS. The blood samples were assayed for CsA concentrations by a specific monoclonal fluorescence polarization immunoassay method. Coadministration of 0.1 capsule/kg of RDS significantly decreased the AUC0-tand Cmaxof CsA by 65% and 72%, and 0.2 capsule/kg of RDS reduced those by 78% and 84%, respectively.In vitrostudies suggested that resveratrol enhanced the activities of P-gp and CYP3A4.In conclusion, RDS decreased the absorption of CsA through induction modulation on P-gp and CYP3A. Transplant patients treated with CsA should be cautioned against taking RDS to reduce the risk of allograft rejection.

Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

Grace-Anne Bent, Paul Maragh, Tara Dasgupta

The acrylamide levels in commercial and homemade Caribbean foods were determined by pre-derivatization of acrylamide to 2-bromopropenamide and analyzed by Gas Chromatography with Mass Spectrometric (GC/MS) detection. Over 100 Caribbean food samples were analyzed for the presence of acrylamide. These samples include: biscuits, breakfast cereals, banana chips and home-prepared foods: breadfruit;Artocarpus altilis, banana fritters, and dumplings. The limit of detection (LOD) for the GC/MS method was found to be dependent on the type of column used for the GC/MS analysis. The DB-1701 and the DB-VRX columns gave LODs of 20 μg/kg and 4 μg/kg, respectively. Acrylamide has not been found in raw foods or foods which have been cooked by boiling. Its content in all other foods had concentrations in the range, 65 - 3640 μg/kg. The relationship between acrylamide levels and precursor concentration as well as the health im

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 31 January 2012

Md. Musfiqur Rahman, Jeong-Heui Choi, A.M. Abd El-Aty, Morad D.N. Abid, Jong-Hyouk Park, ...

During gas chromatography (GC), the matrix can deactivate the active site during the transport of the compound from the injector to the detector. This deactivation capacity varies among matrices, as it is dependant on the concentrations of the different constituent compounds of each matrix. During the analysis of terbufos and its metabolites, two of its metabolites were highly thermolabile, and were readily decomposed inside the GC system. As the matrix can mask the active site, we carried out a matrix-matched calibration in an effort to protect the analyte against decomposition. As a component of our analysis, the pepper matrix was the first to be matched; however, it failed to completely protect the metabolites. Subsequently, a variety of different compounds, including 3-ethoxy-1,2-propanediol, gulonolactone, and sorbitol at 10, 1, and 1 mg/mL were tested; however, none of these generated the desired effect. We surmised that some of the compounds may have decomposed inside the injection port, so we introduced a carbofrit inlet liner, which is highly inert. But, this step did not improve the protective qualities of the matrices. Finally, pepper leaf matrix was added to the pepper matrix, and we observed a profound protective effect for almost all of the analytes tested. A selective detector (flame photometric detector with phosphorus filter) was used to facilitate a high matrix concentration without interaction with the analyte. After resolving the problem of these two metabolites, terbufos and its five toxic metabolites were analyzed in pepper and pepper leaf samples. The recovery rates for terbufos and its metabolites were 73–114.5% with a relative standard deviation of <12%. This method was successfully applied to field samples, and terbufos sulfone, terbufos sulfoxide, and terbufoxon sulfoxide were found as residues in the suspected pepper and pepper leaf samples.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 26 January 2012

J. Zhang, L. Liang, Z. Tian, L. Chen, M. Subirade

Soy protein isolate (SPI) nanoparticles (28-179 nm) were prepared by employing a cold gelation method with a slight modification. The obtained nanoparticles exhibited uniform size distribution and spherical shape with a unique honeycomb-like core structure. Nanoparticle characteristics including size, surface charge and hydophobicity could be adjustable by changing calcium concentration and environmental pH. Generally, higher calcium concentration and lower pH led to formation of nanoparticles with larger size, lower surface charge and hydrophobicity. Both protein conformation and nanoparticle dissociation studies indicated that calcium likely shielded negative charges on the SPI polypeptide chains, and functioned as a salt-bridge to permit polypeptide chains to approach one another. In this process, calcium favoured the development of β-sheet structures to form SPI aggregates stabilized by hydrogen bonding. These aggregates were then associated to build SPI nano-networks through hydrophobic interactions.In vitrostudy indicated that the SPI nanoparticles were non-toxic and mainly located in the cytoplasm when uptaken into Caco-2 cells.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 28 January 2012

Xiao-Juan Li, Wei Wang, Meng Luo, Chun-Ying Li, Yuan-Gang Zu, ...

Solvent-free microwave extraction (SFME) of the essential oil fromDryopteris fragransand its antioxidant activity were investigated. A central composite design combined with response surface methodology was applied to study the influences of extraction time, irradiation power and humidity (proportion of water pretreatment). A maximal extraction yield of 0.33% was achieved under optimal conditions of extraction time 34 min, irradiation power 520 W and humidity 51%. Sixteen compounds, representing 89.65% of the oil, were identified, of which the major ones, (1R,4S,11R)-4,6,6,11-tetramethyltricyclo[5.4.0.0(4,8)]undecan-1-ol (30.49%), 1R,4S,7S,11R-2,2,4,8-tetramethyltricyclo[5.3.1.0(4,11)]undec-8-ene (22.91%) and,1,4,4a,5,6,7,8,8a-octahydro-2,5,5,8a-tetramethyl-1-naphthalenemethanol (15.11%), accounted for 68.51% of the oil. The antioxidant activity of the essential oil was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene/linoleic acid, and reducing power assay, theIC50values were 0.19, 0.09 and 0.18 mg/mL, respectively. All these results suggest that SFME represents an excellent alternative protocol for production of essential oils from plant materials.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 28 January 2012

S. Chamorro, A. Viveros, I. Alvárez, E. Vega, A. Brenes

Grape seed extract and grape pomace are rich sources of polyphenols. The aim of this study was to evaluate the release of polyphenols, the solubilisation of carbohydrate, and the antioxidant capacity of these grape by-products after enzymatic reaction with carbohydrases (cellulolytic and pectinolytic activities) and tannase for 24 hours. The use of tannase in these by-products, and pectinase in grape pomace changed the galloylated form of catechin to its free form, releasing gallic acid and increasing the antioxidant activity. In grape pomace, cellulase treatment was not efficient for phenolic release and antioxidant activity improvement. The addition of carbohydrases to grape pomace, either alone or in combination, degraded the cell wall polysaccharides, increasing the content of monosaccharides. These results provide relevant data about the potential of pectinase, tannase and combinations of enzymes on the release of polyphenols and monosaccharides from grape by-products, improving the antioxidant capacity and the nutritional value.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 28 January 2012

Li-Li Dong, Yu-Jie Fu, Yuan-Gang Zu, Meng Luo, Wei Wang, ...

A simple, rapid and improved method was developed to isolate high-purity baicalein and wogonin fromScutellariae Radix. The method involves endogenous baicalinase-catalysed hydrolysis (EBCH), partition, automated low-pressure preparative chromatography (LPPC) and recrystallisation without multiple and tedious column chromatography. This process was optimised for large scale production of baicalein and wogonin with high yields, low costs and process automation. The transformation ratio of baicalin and wogonoside reached 98.21% and 96.60% after EBCH, leading to an increase of 5.41-fold in baicalein and 3.89-fold in wogonin, compared to a raw sample without hydrolysis. The purity of final products was more than 98% after one-step LPPC and recrystallisation. The experimental results show that EBCH-LPPC is an effective method for preparing high purity antioxidants.

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Publication year: 2012
Source: Food Chemistry, Available online 27 January 2012

Lamis Choueiri, Veronica Sanda Chedea, Antony Calokerinos, Panagiotis Kefalas

The behaviour of 4 known antioxidants (Quercetin, Ascorbic acid, Catechin and Caffeic acid) and their mixtures at different molar ratios was studied in view of elaborating predictions over an eventual pro-oxidant or synergistic antioxidant activity. The Co(II)-EDTA Luminol Chemiluminescence showed that the mixture of Quercetin and Ascorbic acid at ratio 2:1 had the most pronounced antioxidant activity, while that of Quercetin and Caffeic acid at ratio 1:2 showed the least antioxidant activity, which may be interpreted as a strong propensity for pro-oxidant behaviour. The LC-MS analysis for the two mixtures revealed a significant amount of unoxidized Quercetin in the case of Quercetin with Ascorbic acid, whereas in the case of Quercetin with Caffeic acid this amount was negligible. This observation supports the fact that the first combination was more antioxidant than the second, through efficient Quercetin recycling (reduction of the quinone by Ascorbic acid; redox cycling of quinones).

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 27 January 2012

Yan-Zin Chang, Hsiao-Chun Lin, Shu-Ting Chan, Shu-Lan Yeh

A549 cells were pre-incubated with β-carotene (BC) alone or in combination with quercetin or three major quercetin metabolites in human plasma, quercetin 3-glucuronide (Q3G), quercetin 3’-sulfate (Q3’S) and isorhamnetin, followed by incubation with benzo[a]pyrene (BaP), to investigate the effects of these compounds on the BaP-induced harmful effects of BC. All the quercetin metabolites at 10 μM inhibited BaP+BC-induced cell death.Q3’S, Q3G and isorhamnetin also significantly decreased BaP±BC-induced DNA damage by 64, 60 and 24%, respectively.In a similar order, these compounds suppressed BaP±BC-induced cytochrome P450 (CYP)1A1/1A2 expression by10 to 50%.Q3G and Q3’S significantly decreased the intracellular reactive oxygen species formation induced by BaP+BC; however, Q3G had the best effect on decreasing the loss of BC induced by Fe/NTA. The combined effects of quercetin metabolites were additive. This study indicates that quercetin metabolites decrease the BaP-induced harmful effect of β-carotene in A549 cells by downregulating the expression of CYP1A1/1A2, at least in part.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 27 January 2012

Niu Xiaoying, Zhao Zhilei, Jia Kejun, Li Xiaoting

The feasibility of rapid analysis of glucose and fructose in lotus root powder by Fourier transform near-infrared (FT-NIR) spectroscopy was studied. Diffuse reflectance spectra were collected between 4000 and 12432 cm. Calibration models established by partial least-squares regression (PLSR), interval PLS of forward (FiPLS) and backward (BiPLS), back propagation-artificial neural networks (BP-ANN) and least squares-support vector machine (LS-SVM) were compared. The optimal models for glucose and fructose were obtained by LS-SVM with the first 10 latent variables (LVs) as input. For fructose the correlation coefficients of calibration (rc) and prediction (rp), the root-mean-square errors of calibration (RMSEC) and prediction (RMSEP), and the residual predictive deviation (RPD) were 0.9827, 0.9765, 0.107%, 0.115% and 4.599 respectively. For glucose the indexes were 0.9243, 0.8286, 0.543%, 0.812% and 1.785. The results indicate that NIR spectroscopy technique with LS-SVM offers effective quantitative capability for glucose and fructose in lotus root powder.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 27 January 2012

A. Romo-Hualde, A.I. Yetano-Cunchillos, C. González-Ferrero, M.J. Sáiz-Abajo, C.J. González-Navarro

The objective of this work was to obtain and stabilize natural vitamins from red pepper by-products. The method of obtainment was supercritical carbon dioxide extraction, studying different parameters that affect the yield. The highest extraction yield was found at 60 °C, 24 MPa extraction, with no modifier added and 0.2-0.5 mm particle size. The recovered extract was a red-colored oil. The extract was subsequently microencapsulated by spray-drying using gum arabic as wall material to avoid the degradation of vitamin over the storage time. The thermal stability of microcapsules was analyzed by thermal gravimetric analysis (TGA), while size, shape and morphology of microcapsules were studied by scanning electron microscopy (SEM). The microcapsules containing pepper extract were particles of spherical shape with dents on the surface, the average size of these particles was 5.46 μm.

Highlights

Publication year: 2012
Source: Food Chemistry, Available online 27 January 2012

Kinga Zór, Katarzyna Dymek, Roberto Ortiz, Audrey Faure, Ebru Saatci, ...

A method is described for quantification of the beef tenderness marker, calpastatin, in meat samples by amperometric detection. Using a novel bovine recombinant partial calpastatin protein as standard antigen a low detection limit of 0.2 ng/mL was achieved. The influence of the complex matrix was minimised by heat pretreatment and dilution of the samples prior to detection of calpastatin. The relative error between the direct sample measurement and standard addition methods was 5.89%, confirming the accuracy of the developed amperometric immunoassay.

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