Search

The enhanced interest in greater convenience foods has recently led to the expansion of minimally processed potato products. This study investigated the effects of isochoric freezing on pre-peeled potato cubes, including quality attributes (microstructure, texture, and color), nutritional value (ascorbic acid (AA) content, total phenolic content, and antioxidant capacity), and polyphenol oxidase activity. Isochoric freezing (-3 °C/30 MPa) was compared with isobaric freezing (-3 °C/0.1 MPa) and individual quick freezing followed by frozen storage at -20 °C for 4 weeks. The isochoric sample had lower drip loss and volume shrinkage as well as better preserved texture and microstructure than the other samples. All freezing methods caused an increase in total phenolic content and antioxidant capacity, but a decrease in AA content. Also, all freezing methods caused browning of the thawed potatoes, but isochoric freezing delayed its onset for more than 1 week. PRACTICAL APPLICATION: Results showed that isochoric freezing of pre-peeled and cut potatoes caused less freeze damage than isobaric and individual quick freezing, which might find application in the commercial preservation of minimally processed food products.

Efforts are currently directed towards improving the quality of vegetables after freezing and thawing. One of the methods under investigation is isochoric freezing. In this study, we evaluated isochoric freezing for preserving the quality of baby‐leaf spinach. We compared the properties of thawed spinach frozen to −4°C in an isochoric system with those of fresh spinach, thawed spinach frozen to −4°C in an isobaric system and thawed spinach that were commercially frozen. Spinach leaves frozen under isobaric conditions lost mass and thickness, making them softer and translucent. They also lost much of their nutrient content. In comparison, isochoric freezing maintained cell integrity and turgidity. Thawed leaves remained crunchy with characteristics similar to fresh leaves. Isochoric freezing also preserved nutritional content better than isobaric freezing, although significant nutrient losses still occurred.

Due to the perishable nature of fruits and the importance of reducing food waste, an effective preservation technique is required to prolong the shelf life and maintain the physical and nutritional properties of seasonal fruits. In this study, we evaluated isochoric freezing for preserving the quality of sweet cherries. We examined the physical characteristics and nutritional values of thawed cherries frozen to −4 °C or −7 °C in an isochoric system and compared them with those of fresh cherries, thawed cherries that were individually quick frozen and thawed cherries frozen to −4 °C or −7 °C in an isobaric system. We found that isochoric freezing decreased the drip loss and better preserved the color, texture, structure, ascorbic acid, phenolic and antioxidant content of frozen cherries, thereby proving their potential in frozen fruit applications.

This study investigated the potential of isochoric freezing to preserve tomatoes. Isochoric freezing is an emerging technology that preserves biological matter at subfreezing temperatures without any ice damage. Isochoric freezing was compared with freezing under isobaric conditions and with preservation techniques used in the food industry: cold storage at 10 °C and individual quick freezing (IQF). Physicochemical and nutritional properties were evaluated weekly for four weeks. Preservation under isochoric conditions maintained the mass, color, nutrient content (ascorbic acid, lycopene and phenolics) and antioxidant activity of the fresh tomatoes. Also, isochoric preservation led to minimal texture damage. In comparison, mass loss of tomatoes stored at 10 °C for 3 weeks contributed to changes in overall visual quality and firmness as well as significant losses in nutrient content. The greatest mass, texture, and nutrients losses were obtained for tomatoes subjected to IQF and isobaric freezing. The results show that isochoric freezing has the potential to preserve tomatoes while maintaining physicochemical and nutritional properties similar to those of fresh tomatoes which might find application in the commercial preservation of tomatoes.

Methylenecyclcopropylglycine (MCPG) and hypoglycin A (HGA) are naturally occurring amino acids found in various soapberry (Sapindaceae) fruits. These toxins have been linked to illnesses worldwide and were recently implicated in Asian outbreaks of acute hypoglycemic encephalopathy. In a previous joint agricultural and public health investigation, we developed an analytical method capable of evaluating MCPG and HGA concentrations in soapberry fruit arils as well as a clinical method for the urinary metabolites of the toxins. Since the initial soapberry method only analyzed the aril portion of the fruit, we present here the extension of the method to include the fruit seed matrix. This work is the first method to quantitate both MCPG and HGA concentrations in the seeds of soapberry fruit, including those collected during a public health investigation. Further, this is the first quantitation of HGA in litchi seeds as well as both toxins in mamoncillo and longan seeds.

Carvacrol is a volatile monoterpenic phenol and main component of oregano essential oil that shows nonspecific antimicrobial activity against foodborne pathogenic bacteria. Fish‐skin gelatin (FSG) nanofibers encapsulating carvacrol (15%, 20%, 25%, and 30%, w/w FSG) were successfully prepared viasolution blow‐spinning (SBS) technique using lecithin (2.475% wb) as the surfactant. FSG emulsions with lower carvacrol ratios (5% and 10%) showed higher values in particle size and surface tension as well as lower values in viscosity and modulus, which led to failure of maintaining nanofibers shape. The formed carvacrol‐FSG nanofibers showed round and smooth morphologies with average fiber diameters ranging from 103.2 to 138.1 nm as the carvacrol ratio increased from 15% to 30%. Carvacrol was evenly dispersed within the interior of nanofiber matrix. All carvacrol‐FSG nanofibers showed inhibitive effects against the growth of Escherichia coli, Salmonella enterica, and Listeria monocytogenes. Moreover, nanofibers with lower carvacrol ratios showed bigger inhibition zones for E. coliand L. monocytogenes(20 mm compared with 12.5 mm for lowest to highest carvacrol ratios, respectively). Nanofibers stored at 20 °C (51% RH) showed better retention (40% to 60%) for carvacrol during the first 4 weeks of storage, while nanofibers stored at 2 °C (70% RH) showed better retention (10% to 30%) at the end of storage. Results obtained in the study may help with antimicrobial carvacrol addition levels for gelatin fiber preparation using solution blow spinning (SBS) method. SBS gelatin fibers with added antimicrobials have potential applications for food packaging and medical wound dressing.

Methylenecyclopropylglycine (MCPG) and hypoglycin A (HGA) are naturally occurring amino acids found in some soapberry fruits. Fatalities have been reported worldwide as a result of HGA ingestion, and exposure to MCPG has been implicated recently in the Asian outbreaks of hypoglycemic encephalopathy. In response to an outbreak linked to soapberry ingestion, the authors developed the first method to simultaneously quantify MCPG and HGA in soapberry fruits from 1 to 10 000 ppm of both toxins in dried fruit aril. Further, this is the first report of HGA in litchi, longan, and mamoncillo arils. This method is presented to specifically address the laboratory needs of public-health investigators in the hypoglycemic encephalitis outbreaks linked to soapberry fruit ingestion.

A current trend in olive mill wastewater (OMWW) management is to not only decrease environmental pollution but also to extract and utilize valuable by-products. Therefore, the objectives of this study were to explore different techniques for drying a phenolic-rich membrane filtration fraction of OMWW and compare the techniques in terms of the dried product quality and feasibility of the process. The OMWW from 2 (3-phase and 2-phase) California mills was subjected to a 2-step membrane filtration process using a novel vibratory system. The reverse osmosis retentate (RO-R) is a phenolic-rich coproduct stream, and the reverse osmosis permeate is a near-pure water stream that could be recycled into the milling process. Spray-, freeze-, and infrared-drying were applied to obtain solid material from the RO-R. Drying of the RO-R was made possible only with addition of 10% maltodextrin as a carrier. The total soluble phenolics in dried RO-R were in the range 0.15 to 0.58 mg gallic acid equivalents/g of dry weight for 2-phase RO-R, and 1.38 to 2.17 mg gallic acid equivalents/g of dry weight for the 3-phase RO-R. Spray-dried RO-R from 3-phase OMWW showed remarkable antioxidant activity. Protocatechuic acid, tyrosol, vanillic acid, and p-coumaric acid were quantified in all dried RO-R, whereas 3-hydroxytyrosol was found in 3-phase dried RO-R. This combination of separation and drying technologies helps to add value and shelf-stability to an olive oil by-product and increase environmental sustainability of its production.

A carbocation cyclization/rearrangement mechanism for the biosynthesis of isothapsadiene and β-isothapsenol is shown to be energetically viable on the basis of density functional theory (DFT) calculations. In addition, for both isothapsadiene and β-isothapsenol, variable-temperature NMR experiments reveal two equilibrium conformers that undergo hindered exchange. The identities of these conformers, which are related by a chair-flip, are confirmed by DFT calculations on their structures, energies, 1H and 13C chemical shifts, and interconversion pathways.

In Amazonian Peru, the neotropical tree Protium subserratum Engl. (Burseraceae) occurs as distinct ecotypes on low nutrient white-sand (WS), intermediate fertility brown-sand (BS), and nutrient-rich clay (CS) soils. Genetic analysis indicates that these ecotypes are undergoing incipient speciation. Possible drivers of this divergence are habitat-specific herbivore faunas and differing resource availabilities. Protium subserratum, therefore, provides an ideal opportunity to investigate how defense chemistry evolves during lineage divergence. WS and BS races of P. subserratum are host to largely non-overlapping herbivore communities and they differ in chlorogenic acid, flavonoid, and oxidized terpene chemistry. Here, we investigate how another important class of anti-herbivore chemicals, procyanidins (PCs), varies among the ecotypes. We isolated the PCs from leaves of juvenile and adult trees from each ecotype and used spectroscopic and chemical techniques to characterize the chemical structures of their component monomers. We found that WS, BS, and CS ecotypes accumulate ca. 17 % of leaf dry weight as PCs. Within ecotypes, we found very little difference in PC type, neither by site nor by life stage. Among ecotypes, however, we observed a marked divergence in PC composition that arose at least in part from differences in their terminal and extension subunits. In addition, the average polymer length of BS and CS PCs was significantly greater than in WS ecotypes. We conclude that phenotypic differences in PCs in the WS versus BS and CS ecotypes of P. subserratum are consistent with selection by herbivores in different soil types that differ strongly in nutrient availability and may contribute to the evolution of habitat specialization.

Saricaoglu, Furkan Turker/0000-0003-1173-5793; Bridges, David/0000-0002-8507-6498; Wood, Delilah/0000-0003-0894-6362 WOS: 000427527400302 PubMed: 29470390 Cinnamaldehyde, a natural preservative that can non-specifically deactivate foodborne pathogens, was successfully incorporated into fish skin gelatin (FSG) solutions and blow spun into uniform nanofibers. The effects of cinnamaldehyde ratios (5-30%, w/w FSG) on physicochemical properties of fiber-forming emulsions (FFEs) and their nanofibers were investigated. Higher ratios resulted in higher values in particle size and viscosity of FFEs, as well as higher values in diameter of nanofibers. Loss of cinnamaldehyde was observed during solution blow spinning (SBS) process and cinnamaldehyde was mainly located on the surface of resultant nanofibers. Nanofibers all showed antibacterial activity by direct diffusion and vapor release against Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes. Inhibition zones increased as cinnamaldehyde ratio increased. Nanofibers showed larger inhibition effects than films prepared by casting method when S. typhimurium was exposed to the released cinnamaldehyde vapor, although films had higher remaining cinnamaldehyde than nanofibers after preparation. Lower temperature was favorable for cinnamaldehyde retention, and nanofibers added with 10% cinnamaldehyde ratio showed the highest retention over eight-weeks of storage. Results suggest that FSG nanofibers can be prepared by SBS as carriers for antimicrobials. Agriculture and Food Research Initiative Nanotechnology for Agricultural and Food Systems Grant Program [2013-01598]; USDA National Institute of Food and AgricultureUnited States Department of Agriculture (USDA) This project was supported by Agriculture and Food Research Initiative Nanotechnology for Agricultural and Food Systems Grant Program 2013-01598 from the USDA National Institute of Food and Agriculture. We thank Norland Products Inc. for providing gelatin samples for this research.

Carvacrol is a volatile monoterpenic phenol and main component of oregano essential oil that shows nonspecific antimicrobial activity against foodborne pathogenic bacteria. Fish-skin gelatin (FSG) nanofibers encapsulating carvacrol (15%, 20%, 25%, and 30%, w/w FSG) were successfully prepared via solution blow-spinning (SBS) technique using lecithin (2.475% wb) as the surfactant. FSG emulsions with lower carvacrol ratios (5% and 10%) showed higher values in particle size and surface tension as well as lower values in viscosity and modulus, which led to failure of maintaining nanofibers shape. The formed carvacrol-FSG nanofibers showed round and smooth morphologies with average fiber diameters ranging from 103.2 to 138.1 nm as the carvacrol ratio increased from 15% to 30%. Carvacrol was evenly dispersed within the interior of nanofiber matrix. All carvacrol-FSG nanofibers showed inhibitive effects against the growth of Escherichia coli, Salmonella enterica, and Listeria monocytogenes. Moreover, nanofibers with lower carvacrol ratios showed bigger inhibition zones for E. coli and L. monocytogenes (20 mm compared with 12.5 mm for lowest to highest carvacrol ratios, respectively). Nanofibers stored at 20 °C (51% RH) showed better retention (40% to 60%) for carvacrol during the first 4 weeks of storage, while nanofibers stored at 2 °C (70% RH) showed better retention (10% to 30%) at the end of storage.Results obtained in the study may help with antimicrobial carvacrol addition levels for gelatin fiber preparation using solution blow spinning (SBS) method. SBS gelatin fibers with added antimicrobials have potential applications for food packaging and medical wound dressing.

Recent studies have reported the health benefits of pigmented rice cultivars due to the presence of bioactive compounds in the bran layer of caryopsis. This study evaluated the proximate composition, colour, total flavonoids, anthocyanins and proanthocyanidins contents, as well as the total phenolics and antioxidant activity of IAC-600 black rice cultivar and MPB-10 red rice lineage, as a function of degree of milling (DOM), at 0%, 4%, 7%, 10%, 12% and 15% of DOM. Black rice showed a thicker bran layer than red rice. Around 80% and 65% of the ash content of red and black rice, respectively, was distributed in the bran layer. 4% DOM reduced 47% of the fat content in red rice, while in order to reduce similar fat content in black rice, a 7% DOM was necessary. The total free phenolics were around 6- and 7-fold higher than bound phenolics for black and red rice, respectively. Although the non-milled black rice presented higher free and bound phenolics contents than non-milled red rice, the red rice showed higher DPPH and ABTS+ antioxidant activities.

Volatile constituents of commercial black-ripe table olives (Olea europaea) from the United States, Spain, Egypt and Morocco were analysed by gas chromatography and gas chromatography-mass spectrometry (GC-MS). Dynamic headspace sampling was used to isolate a variety of aldehydes, alcohols, esters, ketones, phenols, terpenes, norisoprenoids, and pyridines. Odour unit values, calculated from concentration and odour threshold data, indicate that the following compounds are major contributors to black-ripe table olive aroma: β-damascenone, nonanal, (E)-dec-2-enal, 3-methylbutanal, ethyl benzoate, octanal, 2-methoxyphenol, 2-methylbutanal and 2-methoxy-4-methylphenol. Imported olives contained a variety of fermentation derived volatiles that were not detected in domestic olives. Constituents such as ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, 3-methylbutyl acetate, oct-1-en-3-one, ethyl hexanoate, (Z)-hex-3-enyl acetate, hexyl acetate, ethyl cyclohexanecarboxylate, benzyl acetate and 4-ethylphenol contributed to the odour of imported olives but were not detected in domestic olives.

Flour from the mesocarp of pods of the tree legume known as mesquite (Prosopis spp.) in North America or algarrobo in South America was one of the most important food staples for desert people. Contemporary milling techniques produce a flour similar to that of indigenous peoples that is about 40% sucrose, 25% dietary fiber, and that has a variety of volatiles, such as 2,6-dimethylpyrazine, γ-nonalactone, methyl salicylate, and 5,6-dihydro-6-propyl-2H-pyran-2-one, that contribute to a chocolate and coconut-like aroma. Flour made from the mesocarp contains no stachyose or raffinose, sugars that are responsible for flatulence in other legumes. High-performance liquid chromatography (HPLC) analyses of sugar (sucrose) and citric, malic, and ascorbic acids found considerable ranges in acid/sugar ratio that may be responsible for the wide variations in organoleptic perception. Due to the absence of gliadin, peanut, and soy allergens, the flour is useful in gluten-free formulations. Optimum concentrations for inc...

The peels of different pomegranate cultivars (Molla Nepes, Parfianka, Purple Heart, Wonderful and Vkunsyi) were compared in terms of phenolic composition and total phenolics. Analyses were performed on two silica hydride based stationary phases: phenyl and undecanoic acid columns. Quantitation was accomplished by developing a liquid chromatography with mass spectrometry approach for separating different phenolic analytes, initially in the form of reference standards and then with pomegranate extracts. The high-performance liquid chromatography columns used in the separations had the ability to retain a wide polarity range of phenolic analytes, as well as offering beneficial secondary selectivity mechanisms for resolving the isobaric compounds, catechin and epicatechin. The Vkunsyi peel extract had the highest concentration of phenolics (as determined by liquid chromatography with mass spectrometry) and was the only cultivar to contain the important compound punicalagin. The liquid chromatography with mass spectrometry data were compared to the standard total phenolics content as determined by using the Folin-Ciocalteu assay.

Summary Antioxidant activity (ABTS assay), total phenolics and total anthocyanins were determined in the petioles of twenty-nine rhubarb (Rheum spp.) varieties. Antioxidant activity ranged from 463 ± 50 (Rheum officinale) to 1242 ± 2 μmol Trolox per g DW (Valentine). The phenolic content varied from 673 ± 41 (Loher Blut) to 4173 ± 23 mg GAE/100 g DW (Plum Hutt) and had a low correlation (r = 0.663) with antioxidant results. Seven of the varieties (Plum Hutt, Valentine, Minnesota No. 8, Cherry Red, Cawood Delight, Coulter McDonald and OR 23) had higher total phenolics than kale, a vegetable rich in phenolics. The concentration of anthocyanins ranged from 19.8 ± 1.5 (Crimson Red) to 341.1 ± 41.6 mg/100 g DW (Valentine). The percentages of two main anthocyanins in rhubarb, cyanidin 3-glucoside and cyanidin 3-rutinoside varied from 66.07:33.93, respectively, in Valentine to 9.36:90.64, respectively, in R. officinale.

2-Acetyltetrahydropyridine is an important flavour constituent that imparts roasty, popcorn-like, and cracker-like odours to foods, such as bread, rice, popcorn, taco shells and tortilla chips. We postulated that the homologue with a formyl group in the C-2 position, 2-formyltetrahydropyridine, might have similar desirable odour qualities. Synthesis of this compound was performed by oxidation of 2-piperidinemethanol with silver carbonate supported on Celite®. This reaction produced a major volatile (46.9% of the total volatiles) with a retention index of 1023 on DB-1. GC–O revealed that the unknown had a strong cracker-like odour. The electron impact mass spectrum of the unknown had the following major ions: m / z 82, 111, 54, 68, 28, 43. The m / z 53–54 ratio and m / z 82–83 ratio were consistent with a 1,4,5,6-tetrahydropyridine ring structure. GC-FTIR of the unknown revealed an N–H stretching band at 3435 cm −1 and a Fermi doublet at 2827 and 2713 cm −1 that indicated the presence of an aldehyde. A strong carbonyl absorption band was present at 1703 cm −1 . The unknown was tentatively identified as 2-formyl-1,4,5,6-tetrahydropyridine, based on its retention index, odour quality, mass spectrum, and vapour phase infrared spectrum.

Volatile constituents of the aerial parts of fresh white sage (Salvia apiana Jepson) were isolated by extraction with diethyl ether followed by high vacuum distillation with a solvent assisted favor evaporation (SAFE) apparatus. The isolated volatiles were analyzed by GC and GC/MS. A total of 84 constituents were identifed (constituting 95.1% of the total area), 11 of which were tentatively identifed. The volatiles were characterized by a high content of hydrocarbon and oxygenated monoterpenes. The major constituents identifed were 1,8-cineole (34.5%), camphor (21.7%), β-pinene (7.4%), α-pinene (6.4%), δ-3-carene (6.4%), camphene (3.9%), limonene (3.5%), myrcene (3.2%), and terpinolene (1.3%).

Volatile constituents of Baikal skullcap (Scutellaria baicalensis Georgi) flowers were isolated by solid-phase microextraction (SPME) and analyzed by GC and GC-MS. A total of 64 constituents was identified (constituting 57.1 - 89.9 % of the total area), 13 of which were tentatively identified. β-Caryophyllene (22.3 - 41.5 %), germacrene D (12.4 - 27.5 %), δ-cadinene (3.1 - 5.4 %), γ-muurolene (1.9 - 3.4 %), γ-cadinene (1.6 - 3.1 %), α-humulene (1.6 - 2.6 %), α-copaene (1.4 - 2.3 %), α-muurolene (1.0 - 2.6 %), bicyclogermacrene (1.1 - 2.1 %) and 3-octanone (0.9 - 3.0 %) were the major constituents of the flower volatiles. A small amount (0.5 %) of the uncommon volatile, 2-(methylamino) benzaldehyde was detected in one of the samples.

Piperlongumine, a pyridone alkaloid isolated from Piper longum L., exhibited a potential inhibitory effect on washed rabbit platelet aggregation induced by collagen, arachidonic acid (AA) and platelet activating factor (PAF), without any inhibitory effect on that induced by thrombin. Piperlongumine was used as a lead compound for the synthesis of new antiplatelet agents. Seven synthetic compounds were newly synthesized from 3,4,5-trimethoxycinnamic acid (TMCA). They were 1-piperidin-1-yl-3-(3,4,5-trimethoxy-phenyl)prop-2-en-1-one (1'), 1-morpholin-4-yl-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (2'), 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3'), 1-(2-methylpiperidin-1-yl)-3-(3,4,5-tri-methoxyphenyl)prop-2-en-1-one (4'), 1-(3-hydroxypiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)- prop-2-en-1-one (5'), 1-[3-(3,4,5-tri-methoxyphenyl) acryloyl]-piperidin-2-one (6') and ethyl 1-[3-(3,4,5-trimethoxyphenyl)-acryloyl]piperidine-4-carboxylate (7'). Among those seven synthetic derivatives, 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3') had the most inhibitory effect on platelet aggregation induced by collagen, AA and PAF.

The inhibitory activity of Curcuma longa L. (turmeric) rhizome constituents against sortase A, a bacterial surface protein anchoring transpeptidase, from Staphylococcus aureus ATCC 6538p was evaluated. The activity of the isolated compounds (1-4) was compared to that of the positive control,p-hydroxymecuribenzoic acid (pHMB). The biologically active components of C. longa rhizome were characterized by spectroscopic analysis as the curcuminoids curcumin (1), demethoxycurcumin (2), and bisdemethoxycurcumin (3). Curcumin was a potent inhibitor of sortase A, with an IC50 value of 13.8 +/- 0.7 microg/mL. Bisdemethoxycurcumin (IC50 = 31.9 +/- 1.2 microg/mL) and demethoxycurcumin (IC50 = 23.8 +/- 0.6 microg/mL) were more effective than pHMB (IC50 = 40.6 +/- 1.2 microg/mL). The three isolated compounds (1-3) showed no growth inhibitory activity against S. aureus strain Newman, with minimum inhibitory concentrations (MICs) greater than 200 microg/mL. Curcumin also exhibited potent inhibitory activity against S. aureus cell adhesion to fibronectin. The suppression of fibronectin-binding activity by curcumin highlights its potential for the treatment of S. aureus infections via inhibition of sortase activity. These results indicate that curcumin is a possible candidate in the development of a bacterial sortase A inhibitor.

A major anthocyanin was isolated from the acidified methanolic extract of Beluga black lentils by XAD7 column chromatography and preparative high-performance liquid chromatography. By means of electrospray ionization mass spectrometry and one- and two-dimensional nuclear magnetic resonance spectroscopy, its structure was determined to be delphinidin 3-O-(2-O-β-d-glucopyranosyl-α-l-arabinopyranoside). Keywords: Anthocyanins; black lentils (Lens culinaris); 1D and 2D NMR; delphinidin derivative

Tomato cultivars respond differently to nitrogen (N) sources and to saline conditions, in terms of both yield and fruit quality. Interactions between salinity and ratios with tomato genotypes were studied. The effect of four ammonium levels (0, 1, 2, 4 mM of total 8 mM N) and two salinity levels (0 and 45 mM NaCl) on cv. “R-144”, and the effect of two salinity levels (0 and 45 mM NaCl) on four tomato hybrids (“R-144”, “R-175”, “FA612”, and “FA624”) were studied in two greenhouse experiments. The effects of two levels, (0 and 2 mM out of total N at 8 mM), and two salinity levels (0 and 20 mM NaCl) on large-fruit (“R-144”) and small-fruit (“FA612”) tomato hybrids were also studied in a net-house. The NaCl at 45 mM resulted in a smaller leaf area index (LAI), lower plant dry matter and lower fruit yield than controls. Addition of 1 mM to the nutrient solution contributed to improved growth. Genotypes bearing large fruits were more prone to suffer yield losses under saline conditions than those with ...

Volatile constituents of beechwood creosote were determined using gas chromatography (GC) andgas chromatography-mass spectrometry(GC-MS). Themajorvolatile constituentsofcreosotewere2- methoxyphenol (guaiacol; 25.2%) 2-methoxy-4-methylphenol (4-methylguaiacol; 21.4%), 3-methylphenol (m-cresol; 8.3%) 4-methylphenol (p-cresol; 7.9%) 2-methylphenol (o-cresol; 4.6%) and phenol (2.8%). The antioxidant activity of creosote was evaluated by three different chemical assays. Beechwood creosote exhibited potent inhibitory effects on the formation of conjugated diene hydroperoxides (from methyl linoleate) at concentrations of 500, 750 and 1000 µgml −1 . Creosote had a potent inhibitory effect on the oxidation of hexanal for 40days at a level of 5 µgml −1 and also inhibited malonaldehyde (MA) formation from ethyl arachidonate by 92% at a level of 50 µgml −1 . The antioxidative activity of creosote was comparable with that of the well-known antioxidants α-tocopherol and BHT in the hexanal assay. However, creosote displayed comparatively lower antioxidant activity in the other two assays.  2005 Society of Chemical Industry

The volatile constituents of taheebo (the dried inner bark of Tabebuia impetiginosa Martius ex DC) were isolated by three methods: solvent-assisted flavour evaporation (SAFE); steam distillation under reduced pres- sure, followed by continuous liquid-liquid extraction (DRP-LLE); and high-flow dynamic headspace sampling (including closed-loop stripping) (DHS). The extracts were analysed qualitatively and quantitatively by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The masses of total volatile components recovered from 50 g taheebo by SAFE, DRP-LLE and DHS were 26.3 ± 2.0, 19.4 ± 1.0 and 1.2 ± 0.2 mg, respectively. The major constitu- ents isolated with the SAFE method were 4-methoxyphenol (121.65 µg/g), 4-methoxybenzyl alcohol (96.49 µ µ µ µ µg/g), 1,2- propanediol (92.95 µg/g) and 4-methoxybenzaldehyde (31.33 µ µ µ µ µg/g). The DRP-LLC method yielded 4-methoxybenzaldehyde (64.54 µg/g), 4-methoxyphenol (42.30 µg/g), 5-(2-propenyl)-1,2,3-trimethoxybenzene (elemicin; 41.22 µg/g), and 1-methoxy- 4-(1E)-1-propenylbenzene (trans-anethole; 39.16 µg/g) as major volatiles, while the main compounds recovered with the DHS method were 4-methoxybenzaldehyde (2.61 µg/g), 4-methoxyphenol (2.10 µg/g), 2-methyl-5-(1-methylethenyl)-2- cyclohexen-1-one (carvone; 1.71 µg/g) and 3,7-dimethyl-1,6-octadien-3-ol (linalool; 1.64 µ µ µ µ µg/g). Copyright © 2004 John

The antioxidant activities of naturally occurring plant compounds were measured in a lipid peroxidation system consisting of ethyl arachidonate and Fenton's reagent. Inhibitory effects of 24 plant-derived flavonoids and 5 phenolic acids on malonaldehyde (MA) formation from ethyl arachidonate were examined using gas chromatography (GC) with a nitrogen-phosphorus detector (NPD). Luteolin, which showed the strongest antioxidant activity, inhibited MA formation by 94% and 97% at the levels of 0.5 and 1.0 mM, respectively. The antioxidant activities of the flavones and flavonols decreased in the following order: luteolin > rhamnetin > fisetin > kaempferol > morin > quercetin. Among the flavanones tested, hesperitin, taxifolin, and naringenin exhibited appreciable antioxidant activities (61-84%) at the 1.0 mM level. The inhibitory effect of epigallocatechin gallate (82.5% at the 1.0 mM level) was the strongest among the flavan-3-ols tested. Ferulic acid had the most potent antioxidant activity (74.6% at the 1.0 mM level) of the phenolic acids tested.

Volatiles were isolated from the dried inner bark of Tabebuia impetiginosa using steam distillation under reduced pressure followed by continuous liquid-liquid extraction. The extract was analyzed by gas chromatography and gas chromatography-mass spectrometry. The major volatile constituents of T. impetiginosa were 4-methoxybenzaldehyde (52.84 microg/g), 4-methoxyphenol (38.91 microg/g), 5-allyl-1,2,3-trimethoxybenzene (elemicin; 34.15 microg/g), 1-methoxy-4-(1E)-1-propenylbenzene (trans-anethole; 33.75 microg/g), and 4-methoxybenzyl alcohol (30.29 microg/g). The antioxidant activity of the volatiles was evaluated using two different assays. The extract exhibited a potent inhibitory effect on the formation of conjugated diene hydroperoxides (from methyl linoleate) at a concentration of 1000 microg/mL. The extract also inhibited the oxidation of hexanal for 40 days at a level of 5 microg/mL. The antioxidative activity of T. impetiginosa volatiles was comparable with that of the well-known antioxidants, alpha-tocopherol, and butylated hydroxytoluene.

Lipid oxidation is a very complex and important event causing quality loss of foods, especially those containing highly unsaturated fats. There is growing interest in replacing synthetic antioxidants in food by natural counterparts. Olive leaf is an abundant by-product of the olive oil industry. The aim of this study was to investigate the antioxidant capacity of olive leaf powder (OLP) in minced Atlantic horse mackerel stored at 4 °C over 3 days. OLP was introduced in the minced at concentrations of 0 (control), 1.5, 3.5, and 4.5%. OLP characterization showed high antioxidant capacity and fiber content. The addition of OLP significantly prevented and delayed minced fish oxidation over storage. The antioxidant effectiveness of OLP was concentration-dependent, as observed in all the parameters analyzed. The results showed OLP as a potential natural antioxidant for fish products. Practical applications Olive leaves are an important agrifood by-product produced worldwide. This by-product is valorized for the first time, as far as the authors are aware, as natural antioxidant in fish. Olive leaves are rich in polyphenols (principally oleuropein) and α-tocopherol. Consumers may benefit from this research as there is an increasing demand for natural ingredients, along with concern about the environmental effects of food production. The results of the present study suggest that olive leaf powder can be successfully employed as natural ingredient to prevent oxidation in chilled horse mackerel mince. This allows transforming this by-product stream into a commercially valuable antioxidant.

The root essential oil of Ligusticum grayi Coult. & Rose (Apiaceae) was found to contain three volatile non-terpenoid hydrocarbons: the known C11 compound viridene, whose structure is hereby corrected to 1-[(2Z)-pent-2-en-1-yl]cyclohexa-1,3-diene; and the heretofore unreported C10 compounds 1-[(2Z)-but-2-en-1-yl]cyclohexa-1,3-diene (norviridene), and (Z)-but-2-en-1-ylbenzene (ar-norviridene). These compounds are structurally similar to the 3-alkylphthalides that are widespread in the Apiaceae and, like the latter, probably arise from polyketide precursors.

Mesquite (Prosopis spp.) are woody leguminous plants that belong to the family Leguminosae and grow in arid and semiarid regions of America, Africa and Asia. Prosopis spp. produce indehiscent fruit (pods) that can be milled to yield flour that is sold commercially and is used in pastries and baked goods. The major volatile constituent of mesquite flour was identified as 5,6-dihydro-6-propyl-2H-pyran-2-one on the basis of its Kovats index and mass spectrum. Using d-nonalactone as an internal standard its concentration was determined to be 59.75 ± 7.07 mg/kg (n = 3).

Antimalarial activity of anthothecol, a limonoid of Khaya anthotheca (Meliaceae) against Plasmodium falciparum was tested using a [(3)H]-hypoxanthine and 48h culture assay in vitro. Anthotechol showed potent antimalarial activity against malaria parasites with IC(50) values of 1.4 and 0.17microM using two different assays. Also, gedunin had antimalarial activity with IC(50) values of 3.1 and 0.14microM. However, the citrus limonoids, limonin and obacunone did not show any antimalarial activity. The antimalarial activities were compared with the three currently used antimalarial medicines quinine, chloroquinine and artemisinin.

Volatile constituents of California skullcap (Scutellaria californica A. Gray) flowers were isolated by solid-phase microextraction (SPME) and analyzed by GC and GC/MS. A total of 52 constituents were identified (constituting 90.8% of the total area), 12 of which were tentatively identified. β-Caryophyllene (56.6%), germacrene D (6.9%), methyl 2-methylbutyrate (4.9%), β-bourbonene (4.5%), α-humulene (2.8%), methyl butyrate (2.7%), and α-copaene (1.5%) were the major constituents of the flower volatiles. Due to their low odor thresholds (measured in water) and fruity aroma, methyl 2-methylbutyrate (4.9%; odor threshold = 0.1 ppb) and ethyl 2-methylbutyrate (0.7%; odor threshold = 0.007 ppb) were considered to be important contributors to the characteristic sweet, apple-like odor of these flowers.

Anthocyanidins, prepared by the acid hydrolysis of black bean and blackberry anthocyanins, were deposited in C18 solid-phase extraction (SPE) cartridges from four different manufacturers. The amoun...

The effects of composition, temperature, and storage time on the textural attributes of a starch–sucrose gel system were determined by means of textural profile analysis (TPA) tests. Mixtures of high amylose corn starch, sucrose, and water were jet cooked at temperatures of 110–150 °C, rapidly cooled to gels on a refrigerated belt, and stored at 1 °C. Treatment temperature, storage time, sucrose/starch ratio and water added/solids ratio were used as independent variables. The ranges of sucrose, starch, and water added were 0–14.9, 14.4–33.6, and 48.3–77.8 g/kg, respectively. All four independent variables were found to be significant in second order response surface equations, describing all textural attributes but adhesiveness. Hardness, fracturability, gumminess, and chewiness were exponentially related to quadratic functions of the variables while resilience, cohesiveness, and springiness were linearly related. Adhesiveness values were low and independent of the variables. In general, values of textural attributes increased with temperature and storage time, and were inversely related to sucrose/starch ratio and water added/solids ratio.

A series of unsaturated branched esters were purified by preparative gas chromatography and their odor thresholds were determined using sensory panel methods. In general, unsaturated branched esters had higher odor thresholds than their saturated counterparts. Double bond position and configuration had marked influences on the odor threshold. In most cases, the addition of a double bond in the C-2 position of the acid resulted in significantly higher odor thresholds while the addition of a double bond in positions further away from the acid carbonyl had a smaller effect on the odor threshold. Ethyl 2-methyl-4-pentenoate had the lowest odor threshold (0.01 μL/10 3 L) of the esters tested while methyl (E)-2-methyl-2-butenoate (methyl tiglate; 130 μL/10 3 L) had the highest odor threshold.

Three anthocyanins were isolated from the acidified methanol extracts of UI 911 black beans (Phaseolus vulgaris L.) using solid phase extraction and preparative high-performance liquid chromatography . The anthocyanins were characterized using chromatographic and spectroscopic methods as delphinidin 3-glucoside (56%), petunidin 3-glucoside (26%), and malvidin 3-glucoside (18%). The monomeric anthocyanin content was 213 ± 2 mg/100 g of black beans (moisture content was 10.04 ± 0.02%). Keywords: Black beans; antioxidants; pigments; anthocyanins; electrospray ionization mass spectrometry

Seven commonly used frying oils and fats (beef tallow, canola oil, partially hydrogenated canola oil, corn oil, cottonseed oil, soybean oil, and partially hydrogenated soybean oil) were heated at t...

MS with GC-RI evidence was found for the presence of linden ether in cooked carrot (Daucus carota). Evaluation of the GC effluent from cooked carrot volatiles using aroma extract dilution analysis (AEDA) found linden ether with the highest flavor dilution (FD) factor. Others with 10-fold lower FD factors were β-ionone, eugenol, the previously unidentified β-damascenone, (E)-2-nonenal, octanal (+ myrcene), and heptanal. All other previously identified volatiles showed lower FD factors. Odor thresholds, concentrations, and odor activity values of previously identified compounds are reviewed. This indicated that at least 20 compounds occur in cooked carrots above their odor thresholds (in water). Compounds showing the highest odor activity values included β-damascenone, (E)-2-nonenal, (E,E)-2,4-decadienal, β-ionone, octanal, (E)-2-decenal, eugenol, and p-vinylguaiacol.

A series of straight chain and branched esters (ethyl acetate to 2-nonyl acetate) were purified by preparative gas chromatography and their odour thresholds were determined using sensory panel methods. Pentyl acetate and 2-butyl acetate had the lowest odour thresholds of the straight chain and branched acetates, respectively. Addition of a methyl group at the 1-position of the alcohol did not have a consistent effect on the odour threshold. For ethyl acetate, propyl acetate, butyl acetate and heptyl acetate the addition of a methyl group in the 1-position caused a decrease in the odour threshold; whereas for pentyl acetate, hexyl acetate and octyl acetate the addition of a methyl group in the 1-position caused an increase in the odour threshold.

The volatile constituents of used frying oils obtained from a local food-processing plant were isolated by simultaneous distillation−extraction and fractionated by silica gel column chromatography. The isolates were analyzed by capillary gas chromatography and combined capillary gas chromatography−mass spectrometry, resulting in the identification of 140 compounds. The major constituents identified were 1-pentanol, hexanal, furfuryl alcohol, (E)-2-heptenal, 5-methylfurfural, 1-octen-3-ol, octanal, 2-pentylfuran, (E)-2-octenal, nonanal, (E)-2-nonenal, and hexadecanoic acid. Keywords: Frying oil; volatiles; simultaneous steam distillation−extraction; deep-fat frying

A series of branched esters (methyl 2,2-dimethylpropanoate to ethyl 2-ethylhexanoate) were purified by preparative gas chromatography and their odor thresholds were determined using sensory panel methods. The odor thresholds reached a minimum with the butanoate and pentanoate esters. In general, the branched esters have much lower odor thresholds than their straight chain counterparts. Replacing methyl and ethyl branch substituents with mercapto- or hydroxy-groups resulted in higher odor thresholds.

As part of our efforts to identify volatile decomposition products in used frying oils, a series of 4- and 5-oxoaldehydes were synthesized, purified, and characterized by gas chromatography, gas chromatography-mass spectrometry, gas chromatography-Fourier transform infrared spectrometry, and nuclear magnetic resonance spectrometry. Oxoaldehydes have been proposed as possible precursors of alkylfurans, which have potential anticancer effects. In a model reaction 4-oxononanal was refluxed in hexane for 40 days and only trace amounts of 2-pentylfwan were produced, suggesting that it is not a major precursor of the furan. The volatile constituents of used frying oils obtained from commercial food processors were studied, and 4-oxohexanal, 4-oxooctanal, 4-oxononanal, and 4-oxodecanal were identified

Infrared heating was recently used to develop a more efficient roasting technology than traditional hot air roasting. Therefore, in this study, we evaluated the shelf-life of almonds roasted with three different approaches, namely infrared (IR), sequential infrared and hot air (SIRHA) and regular hot air (HA). Nine medium roasted almond samples produced by the aforementioned heating methods were processed at three different temperatures (130, 140 and 150 C), packed in paper bags and then stored at 37 C for three, six or eight months. Shelf-life of the roasted almonds was determined by measuring the changes in colour, peroxide value, moisture content, water activity, volatile components and sensory quality. No significant difference was observed in moisture content and water activity among the almond samples processed with different roasting methods and stored under the same conditions. GC/MS analysis showed that aldehydes, alcohols, and pyrazines were the main volatile components of almonds. Aliphatic alde- hydes such as hexanal, (E)-2-octenal, and nonanal were produced as off-odours during storage. Although the overall quality of roasted almonds produced with SIRHA and HA heating was similar during the first three months of storage, their peroxide value and concentration of aliphatic aldehydes differed signifi- cantly for different roasting methods and increased significantly in all roasted samples during storage. We postulate that hexanal and nonanal might be better indicators of the shelf life of roasted almonds than the current standard, peroxide value.