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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.

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.

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.

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.

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.

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

Des applications des colonnes capillaires contenant la β-cyclodextrine permethylee sont presentees telles que des separations d'enantiomeres de monoterpenes, de sesquiterpenes et des esters