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Ozone is a powerful oxidant agent which is used in foods preservation on account of its ability of killing microorganisms. In the present study, the combined effects of ozone gas treatment and heat...

The objective of the present study was to investigate the combined effect of different ozone dose (2, 5, and 10 mg/L) and of vacuum packaging on shelf life extension of fresh chicken legs, packaged with polyamide/polyethylene bags and stored at 4 ± 1 °C, for 16 days. Parameters considered were: microbiological (TVC, Pseudomonas spp., LAB, Yeasts and moulds, and Enterobacteriaceae), physicochemical (pH, colour parameters) and sensory (odour, appearance, texture, and taste) attributes. The results obtained in this study showed that physicochemical parameters varied significantly ( P 0.05 ) depending on ozonation dose and storage time. Populations of spoilage flora along with sensory properties, were affected by packaging technology and storage time ( P 0.05 ). Conclusively, the combination of gaseous ozone of 10 mg/L and vacuum packaging, under refrigeration, resulted to a 6 days shelf life extension of chicken legs, as compared to single vacuum packaging. The modeling of microbial growth, resulted in the collection of positive results ( P 0.05 ).

The aim of the present study was to investigate the effectiveness of UV-C and thermal treatments on the shelf life of carrot juice. Carrot juice samples were exposed to UV-C radiation and thermal treatment. After the treatments, all carrot juice samples were stored at 4 °C for 16 days. Parameters taken into account were: physicochemical [colour values (L*, a*, and b*) and browning index, viscosity, optical density, density, pH, turbidity], microbiological [total plate count mesophilic, total plate count psychrotrophic, lactic acid bacteria Enterobacteriaceae and yeast and moulds) and sensory attributes. Results showed that the shelf life of carrot juice samples was 4 days for the fresh (control samples) and increased to 12 days for the thermally and UV-Ctreated, respectively. In addition, no significant changes occurred in the investigated physicochemical parameters, while sensory characteristics were not downgraded by UV-C treatment. Present results obtained, support the use of UV-C technology for improving shelf life stability of carrot juice.

The objective of the present work was to characterize prickly pear juice prepared from prickly pear fruits of the wild cultivar in terms of shelf life (air and vacuum packaging), sensory stability (odour, taste, and appearance) physicochemical parameters (acidity, vitamin C, pH, electrical conductivity, total dissolved solids, specific weight, total sugar content, and colour coordinates L*, a*, b*) and bio-functional properties [in vitro antioxidant activity (AA%) and total phenolic content (TPC)]. For this purpose fruits were collected during August 2017 from 3 different geographical zones in Peloponnese. The shelf life of prickly juice was extended by 5 days in vacuum compared to air packaging, whereas it was found to be a rich source of phytochemicals and a natural antioxidant agent (AA of 67.33 ± 5.89–75.63 ± 4.41% and TPC of 3234.5 ± 978.2–7592.1 ± 2441.0 mg GAE L(−1)), in relation to fruit geographical origin (P

The aim of the present study was to investigate the effect of different ozone doses (2, 5, and 10 mg/L) on shelf life extension of fresh chicken legs, packaged in polyamide/poleyethylene bags and stored at 4 ± 1 °C, for a period of 12 days. Parameters taken into account were: microbiological (Total viable count, Pseudomonas spp., Lactic acid bacteria, Yeasts and molds, and Enterobacteriaceae), physicochemical (pH, colour) and sensory (odor, appearance, texture, and taste) attributes. Results showed that colour parameter values (L*, a*, and b*) were not affected by the gaseous ozone dose, whereas only L* and b* were reduced during storage in all samples. pH was reduced by storage time but was not affected by ozonation dose and packaging. Total viable count and Pseudomonas spp., increased statistically significant with ozonation dose and storage time, but were not affected by packaging. Yeasts, molds, Enterobacteriaceae, and Lactic acid bacteria, were decreased during storage, packaging and ozonation dose. Finally, sensory examination (appearance, texture, odor and taste) showed that samples treated with ozone concentration of 10 mg/L retained the original characteristic features of fresh chicken legs as compared to the control samples. The gaseous ozone treatment of 10 mg/L for 1 h, to chicken legs packaged in plastic containers of polyamide/polyethylene under refrigeration, is appropriate for maintaining freshness and quality of chicken, since their shelf life was extended by 4 days, as compared to the control samples.

Diketopiperazines (DKPs) are cyclic dipeptides which have been detected in a variety of natural products, especially in thermally treated or fermented foods and beverages, providing a metallic bitter taste. DKPs, mainly due to their characteristic heterocyclic system, have been reported to exhibit a broad spectrum of biological activities including antimicrobial, antiviral, antitumor, antihyperglycaemic and antimutagenic. In the present study, several DKPs were identified in seven different Greek varieties of processed olives using HR-LC-MSn. The identification of DKPs in olive samples was achieved by comparison of their retention time and fragmentation pattern with reference DKP standards. The MSn spectra were identical to confirm the presence of specific compounds because their results associate both fragmentation pattern and fragments’ intensity. Nine compounds were found out of a total of 19 standard DKPs. The most prominent diketopiperazine was the cyclo(Phe-Phe) followed by and cyclo(Phe-Pro). Varieties where most DKPs were identified were Kothreiki, Kalamon, Throumpoelies and Helidoni.

The objectives of the present work were: (a) to characterize bee pollen from the region of Epirus in terms of biofunctional activity parameters as assessed by (i) the determination of specific polyphenols using high performance liquid chromatography electrospray ionization mass spectrometry (HPLC/ESI-MS), (ii) antioxidant capacity (DPPH assay), and (iii) total phenolic content (Folin-Ciocalteu assay), and (b) to prepare yoghurts from cow, goat, and sheep milk supplemented with different concentrations of ground bee pollen (0.5, 1.0, 2.5 and 3.0%, w/v), and study afterwards the trend in antioxidant capacity and total phenolic content along with product&rsquo, s sensory properties. Results showed that bee pollen ethanolic extracts are a rich source of phytochemicals based on the high total phenolic content and in vitro antioxidant activity that were monitored. The addition of ground bee pollen in yoghurts resulted in a food matrix of a higher in vitro antioxidant capacity and total phenolic content, whereas it improved the yoghurt&rsquo, s taste, odour, appearance, and cohesion, the latter indicates its beneficial use as a general food surface and interface material enhancer due to the possible formation of surface/interface active lipid-linked proteins. Based on the present findings, bee pollen yoghurt is proposed as a novel and costless functional food whereas it may comprise a research basis for food or material science in the scientific society of the future. Results were further supported by implementation of advanced chemometric analyses providing a full characterization of the product&rsquo, s uniqueness.

Greenhouse tomatoes were exposed to gaseous ozone for 1 h at different concentrations (0.5, 1, and 2 mg/L), packaged in low-density polyethylene (LDPE) bags and stored at 4 ± 1 °C for 49 days. Peel firmness, color parameter, browning index values, weight loss, acidity, total viable count, psychrotrophs, yeasts and molds, and sensory analyses were carried out. Results showed significant differences on parameters determined, depending on storage time and treatment (p ). Sensory evaluation showed that ozonated tomatoes (especially at 2 mg/L) retained a fresh character compared to untreated samples, for an extended period of ca. 15 days.

The moisture sorption isotherms of Greek durum wheat semolina were determined at 25, 30, 35, and 40°C using the gravimetric (static) and the Novasina hygrometric methods. Good agreement was found between sorption isotherms for semolina obtained with the Novasina and the static gravimetric methods. Sorption isotherms were of the characteristic sigmoid shape (BET type II). Sorption data showed that the moisture content increased while water activity was increasing at a constant temperature, and decreased while temperature was increasing at a constant relative humidity. The water vapor sorption kinetics of semolina was also studied using the static gravimetric method. With the temperature and relative humidity rising, the rate of water sorption also increased. The increase, though, was not stable. Initially, there was a steep rise, but while moisture contents reached equilibrium the rate was substantially decreased. The experimental data were successfully fitted to 7 of widely used isotherm models (B.E.T., G.A.B., Freundlich, Halsey, Henderson, Chung and Pfost, and Oswin). Isosteric heat of sorption (ΔHs) of the studied substrate (semolina) was also determined using the modified Clausius–Clapeyron equation. The steep increase (absolute values) of ΔHs at low moisture contents indicate that water molecules interact more strongly at lower moisture contents.

Food-grade plasticized polyvinylidene chloride/polyvinyl chloride (PVDC/PVC) film (saran wrap) containing acetyl tributyl citrate (ATBC) plasticizer was used to wrap cod and herring fillets. The ratio of film surface to weight of food was ca. 89:1, in contrast to the generally agreed relationship of 6 dm2 to 1 kg food (6:1). Wrapped fish samples were subjected to electron beam irradiation at doses equal to 5 and 10 kGy, stored at 4 °C and analyzed for ATBC content at time intervals between 12 and 240 h of contact. Determination of the analyte was performed by ultrasonic-assisted solvent extraction followed by analysis on a gas chromatograph coupled with flame ionization detector. Final ATBC concentrations in cod fillets ranged from 11.1 to 12.8 mg/kg, while the corresponding values for herring samples were between 32.4 and 33.4 mg/kg. Data showed that e-beam radiation at pasteurizing doses did not significantly affect the copolymer’s specific migration characteristics. On the contrary, fat content of the packaged fish fillets substantially affected the diffusion coefficient (D) values, as well as the extent to which migration of ATBC occurred. No violations of the tolerable daily intake (TDI) of 1.0 mg/kg body weight set by the EU for ATBC were found in the present study. However, food overwrapping or rewrapping with flexible films is often applied in household applications. Since in such cases unrealistically high plasticizer concentrations are determined experimentally, present specific migration limits (SML) should be redefined on a different basis.

BACKGROUND: The present study investigated the effect of irradiation, active and modified atmosphere packaging, and storage conditions on quality retention of raw, whole, unpeeled almonds. Almond kernels were packaged in barrier and high-barrier pouches, under N2 or with an O2 absorber and stored either under fluorescent lighting or in the dark at 20 °C for 12 months. Quality parameters monitored were peroxide value, hexanal content, colour, fatty acid composition and volatile compounds. Of the sensory attributes colour, texture, odour and taste were evaluated. RESULTS: Peroxide value and hexanal increased with dose of irradiation and storage time. Irradiation resulted in a decrease of polyunsaturated and monounsaturated fatty acids during storage with a parallel increase of saturated fatty acids. Volatile compounds were not affected by irradiation but increased with storage time indicating enhanced lipid oxidation. Colour parameters of samples remained unaffected immediately after irradiation. For samples packaged under a N2, atmosphere L* and b* values decreased during storage with a parallel increase of value a* resulting to gradual product darkening especially in irradiated samples. CONCLUSION: Non-irradiated almonds retained acceptable quality for ca. 12 months stored at 20 °C with the O2 absorber irrespective of lighting conditions and packaging material oxygen barrier. The respective shelf life for samples irradiated at 1.0 kGy was 12 months packaged in PET-SiOx//LDPE irrespective of lighting conditions and 12 months for samples irradiated at 3 kGy packaged in PET-SiOx//LDPE stored in the dark. Copyright © 2010 Society of Chemical Industry

article i nfo The present study investigated the effect of active and modified packaging as well as packaging material oxygen permeability on quality retention of dark chocolate with hazelnuts. Dark chocolate was packaged in: a) polyethylene terephthalate//low density polyethylene (PET//LDPE), and b) polyethylene terephthalate coated with SiOx//low density polyethylene (PET-SiOx//LDPE). Samples were packaged either under, vacuum or N2 or with an oxygen absorber and stored in the dark at 20 °C for a period of 12 months. "Commercial" control samples for comparison purposes consisted of chocolate packaged in aluminum foil in air while "model" control samples used for sensory evaluation consisted of chocolate packaged in glass jars and stored at �18 °C. Quality parameters monitored were: peroxide value, hexanal content, color, fatty acid composition and volatile compounds. Of the sensory attributes color, texture, odor and taste were evaluated. PV ranged between 0.80 for fresh dark chocolate with hazelnuts and 6.51 meq O2/kg chocolate fat for commercially packaged samples after 12 months of storage. Respective values for hexanal were 0.53 and 7.56 mg/kg. % Saturated fatty acids (SFA) increased with a parallel decrease in monounsaturated fatty acids (MFA) and polyunsaturated fatty acids (PUFA) after 12 months of storage mainly in least protected samples (commercial package). Likewise, after 12 months of storage an increase in concentration of aldehydes, ketones, alcohols and alkanes (pb0.05) with a parallel decrease in pyrazines where observed especially in case of least protected products after 6 and 12 months of storage. In general after 12 months of storage chocolate showed whitening of the surface resulting to an increase in L* and a* values (pb0.05) and a decrease in b* value. Dark chocolate with hazelnuts retained acceptable quality for ca. 8 months in commercial packages. For samples packaged in PET//LDPE irrespective of storage atmosphere the shelf life was 8 to 9 months and for samples packaged in PET-SiOx//LDPE irrespective of storage atmosphere the shelf life was 11 months. Finally for samples packaged with an oxygen absorber irrespective of packaging material the shelf life was at least 12 months. Industrial relevance: Chocolate packaged with an oxygen absorber in a barrier packaging material will maintain its aroma, taste and nutritional quality substantially longer than other packaging methods.

Ten wild edible mushroom species ( Cantharellus cibarius, Rusula delica var chloroides, Ramaria largentii, Hygrophorus russula, Amanita caesaria, Fistulina hepatica, Boletus aureus, Armillaria tabesceus, A. mellea, Lepista nuda ) from West Macedonia and Epirus, regions of Northern Greece, were analysed for their basic composition (moisture, crude protein, crude fat, total carbohydrates and ash) and metal content profile (Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb, Cd, Al, As and Sn). The moisture content of mushrooms varied from 8.66% ( L. nuda ) to 17.43% ( C. cibarius ). The dry matter of mushrooms contained 21.57% ( C. cibarius ) – 34.77% ( A. caesaria ) proteins, 2.10% ( A. mellea ) – 6.00% ( H. russula ) fat, 5.61% ( Russula delica ) – 9.44% ( C. cibarius ) ash and 53.33% ( H. russula ) – 66.87% ( A. tabesceus ) carbohydrates. The metal content of mushroom samples ranged 688.7–1150.7 for Mg, 0.12–5.34 for Cr, 7.19–62.63 for Mn, 38.9–499.0 for Fe, 0.05–7.22 for Co, 0.76–9.93 for Ni, 7.38–75.06 for Cu, 34.43–98.99 for Zn, not detected–1.16 for Pb and 0.07–1.80 μg/g for Cd. As, Sn and Al concentrations were under the detection limit of the method used. The detection limits of the method for As, Sn and Al are 0.02 μg/g for each element.

The present study investigated the effect of packaging and storage conditions on quality of raw shelled walnuts. Walnut kernels were packaged in: (a) low density polyethylene (LDPE), 55 μm in thickness in air, (b) polyethylene terephthalate||polyethylene (PET||PE), 70 μm in thickness under N2, and (c) PET-SiOx||PE pouches, 62 μm in thickness under N2. Samples were stored either under fluorescent light or in the dark at 4 or 20 °C for a period of 12 months. Quality parameters monitored were peroxide value (PV), hexanal, 2-thiobarbituric acid (TBA), odor, and taste of product. PV ranged between 0.3 for fresh walnut kernels and 31.4 meq O2/kg oil for walnuts packaged in PE pouches exposed to light after 12 months of storage. Respective values for hexanal were degree of O2 barrier > lighting conditions.

Summary The volatile composition of the wild edible mushroom species Hygrophorus chrysodon, Hygrophorus eburneus and Hygrophorus russocoriaceus was analysed by headspace-solid phase microextraction combined with gas chromatography–mass spectrometry. Forty-five volatile compounds were detected, including alcohols, aldehydes, ketones, hydrocarbons, esters and terpenes. The most abundant compounds in the three species were 3-methyl butanal, hexanal, p-cymene, 3-octanone, 1-octen-3-one, 3-octanol, 1-octen-3-ol and benzoic acid methyl ester. The concentration of eight-carbon (C8) compounds relative to the total volatiles varied widely ranging from 24.14% to 61.41% among the three species. Finally, the presence of sesquiterpenes only in Hygrophorus russocoriaceus, confirms the characteristic distinctive cedar odour of this species.

The present study evaluated the quality of raw unpeeled almonds as a function of irradiation dose in order to determine dose levels causing minimal undesirable changes to almonds. Physicochemical (color, peroxide value, hexanal content, fatty acid composition, volatile compounds) and sensory (color, texture, odor, taste) properties of almonds were determined as a function of irradiation dose. Results showed a ten-fold increase in peroxide value (PV) after irradiation at a dose of 7 kGy. A small but statistically significant ( p p > 0.05) changes were recorded in polyunsaturated fatty acids (PUFA) up to a dose of 7 kGy while monounsaturated fatty acids (MUFA) decreased manifested as a respective increase in saturated fatty acids (SFA) up to 3 kGy. Volatile compounds such as aldehydes, ketones and alcohols increased with increasing irradiation dose indicating enhanced lipid oxidation. Color parameter L ⁎ decreased ( p 3 kGy while color parameters a ⁎ and b ⁎ remained unaffected by irradiation. Sensory analysis showed that almonds remained organoleptically acceptable up to a dose of 3 kGy. Industrial Relevance: Irradiation is very efficient in controlling insects and growth of aflatogenic Aspergillus spp. in dry nuts.

Volatile and non-volatile radiolysis products and sensory changes of five-layer food packaging films have been determined after gamma irradiation (5–60 kGy). Barrier films were based on polyamide (PA) and low-density polyethylene (LDPE). Each film contained a middle buried layer of recycled LDPE or 100% virgin LDPE (control samples). Data showed that a large number of radiolysis products were produced such as hydrocarbons, alcohols, carbonyl compounds, carboxylic acid. These compounds were detected in the food simulant after contact with all films even at the lower absorbed doses of 5 and 10 kGy. The type and concentration of radiolysis products increased progressively with radiation dose, while no new compounds were detected as a result of the presence of recycled LDPE. In addition, irradiation dose appears to influence the sensory properties of table water in contact with films.

Eight different species of wild edible mushrooms ( Cantharellus cibarius, Hydnum repandum, Lactarius salmonicolor, Xerocomus chrysenteron, Agaricus cupreobrunneus, Amanita franchetii, Hygrophorus eburneus and Hygrophorus chrysodon ) representing seven different families ( Cantharellaceae, Hydnaceae, Boletaceae, Russulaceae, Agaricaceae, Amanitaceae, Hygrophoraceae ) growing in Epirus (Ioannina) and West Macedonia (Grevena, Kastoria), regions of Greece were analyzed by atomic absorption spectrometry (AAS) for their metal (Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb, Cd, Al, As and Sn) content. All metal concentrations were determined on a dry weight basis (d.w.). The metal content of mushroom samples ranged from 739–1165 μg/g d.w. for Mg, 0.41 to 13.1 μg/g d.w. for Cr, 11.4 to 100 μg/g d.w. for Mn, 46.3 to 317 μg/g d.w. for Fe, not detected–3.34 μg/g d.w. for Co, 0.28 to 10.1 μg/g d.w. for Ni, 3.80 to 32.6 μg/g d.w. for Cu, 35.9 to 96.9 μg/g d.w. for Zn, not detected–1.37 μg/g d.w. for Pb and 0.08 to 0.41 μg/g d.w. for Cd. As, Sn and Al concentrations were under the detection limit of the method used. This research proves that wild edible fungi which consumed traditionally in Epirus (Ioannina) and West Macedonia (Grevena, Kastoria), Greece can be used in well-balanced diets due to their high contents of functional minerals. Also, their low contents of heavy metals (Pb, Cd and As) shows that collection areas are not polluted, therefore all collected edible mushroom species can be unreservedly consumed without any health risk.

The effect of electron-beam and gamma irradiation under vacuum on the physicochemical and mechanical properties of commercial polypropylene (PP) syringes was studied. Irradiation doses of 30, 60 and 120 kGy were used while for comparison purposes respective non-irradiated (control) PP syringes were also studied. Mechanical tests, differential scanning calorimetry analysis, color determination and FTIR were carried out to evaluate the effect of both irradiation treatments (electron-beam and gamma irradiation) on PP syringes. Both compression strength and % extension at break decreased with increasing irradiation dose. Melting temperature as well as specific melting enthalpy also decreased while the degree of yellowness increased with increasing irradiation dose. Minor differences in FTIR spectra were observed after irradiation treatment.

The effect of gamma radiation on the migration of both di-(2-ethylhexyl)adipate (DEHA) and acetyltributyl citrate (ATBC) plasticizers from PVC film into the food simulant isooctane was studied as a function of time (0–48 h) at 20 °C. Food-grade PVC cling-film used contained 5.3% (w/w) DEHA, 3.0% (w/w) ATBC and polyadipate polymeric plasticizer. Irradiation of the films was carried out at doses of 5, 10 and 25 kGy using a [60Co] gamma-radiation source. Determination of both plasticizers was performed using a direct gas chromatographic method. No radiation-induced transformation of the two plasticizers was observed after absorbed doses of 5–25 kGy. DEHA migrated rapidly into isooctane in contrast with ATBC. ATBC migrating amounts at equilibrium were approximately three times lower than the corresponding amounts of DEHA. Irradiation at doses 10 and 25 kGy had a small but statistically significant (P

Changes in volatile profiles of whole pasteurized milk stored under fluorescent light at 4 °C, packaged in different containers were monitored for a period of 7 days in a study designed to differentiate between light-induced oxidative and purely autoxidative effects related to packaging material. Changes in volatiles were measured using solid-phase microextraction-gas chromatography/mass spectroscopy, while microbiological and sensory analyses were used to assess milk quality. Two distinct patterns of milk flavour deterioration were observed. In light-exposed samples, a light-induced oxidation mechanism prevailed while in light-protected samples, an autoxidation mechanism was apparent. Under both conditions, the concentration of selected odorous compounds increased with storage time. Microbiological data correlated poorly with both sensory and GC/MS data. Sensory data correlated well with selected volatile compounds pointing to dimethyl disulphide, pentanal, hexanal and heptanal as potential markers of fresh milk quality. Based on sensory analysis, the optimal shelf life of the whole pasteurized milk used in this study was approximately 5 days.

The effect of gamma radiation (doses 5–60 kGy) on the thermal, mechanical and permeation properties, as well as on IR-spectra of experimental five-layer food packaging films were studied. Films contained a middle buried layer of recycled low-density polyethylene (LDPE) comprising 25–50% by weight of the multilayer structure. Representative films containing 100% virgin LDPE as the buried layer were taken as controls. Results showed that the percentage of recycled LDPE in the multilayer structure did not significantly ( p 0.05 ) affect the melting temperature, tensile strength, percent elongation at break, Young's modulus, oxygen, carbon dioxide and water vapour transmission rate values and the IR-spectra of the non-irradiated and irradiated multilayer films. Irradiation (mainly the higher dose of 60 kGy) induced certain small, but statistically significant ( p 0.05 ) differences in the mechanical properties of multilayer films (with or without recycled LDPE layer) while no significant differences were observed in the thermal properties and in the gas and water vapour permeability of multilayer films. The above findings are discussed in relation to the good quality of the pre-consumer scrap used in the present study.

In the present study, the effect of electron-beam irradiation on physicochemical and mechanical properties of polypropylene (PP) syringes was studied. Three irradiation doses (30, 60 and 120 kGy) were applied to all samples. Non-irradiated PP syringes were used as control samples. Electron-beam irradiation caused an increase in the degree of yellowness and in the extractable radiolysis products. A decrease in compression strength and extension at break was the result of electron-beam irradiation on mechanical properties of PP syringes. Minor differences were observed in FTIR spectra, mainly in the region of 1720 cm−1, corresponding to the absorption of carbonyl compounds. Gas chromatography/mass spectrometry (GC/MS) analysis indicated the formation of a number of radiolysis compounds while a number of compounds initially present in non-irradiated syringes were destroyed by the irradiation. The degradation on polymer properties caused by electron-beam irradiation was less severe than that caused by gamma irradiation.

The effects of gamma-irradiation (5-60 kGy) on radiolysis products and sensory changes of experimental five-layer food-packaging films were determined. Films contained a middle buried layer of recycled low-density polyethylene (LDPE) comprising 25-50% by weight (bw) of the multilayer structure. Respective films containing 100% virgin LDPE as the buried layer were used as controls. Under realistic polymer/food simulant contact conditions during irradiation, a large number of primary and secondary radiolysis products (hydrocarbons, aldehydes, ketones, alcohols, carboxylic acids) were produced. These compounds were detected in the food simulant after contact with all films tested, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food preservation). The type and concentration of radiolysis products increased progressively with increasing dose. Generally, there were no significant differences in radiolysis products between samples containing a buried layer of recycled LDPE and those containing virgin LDPE (all absorbed doses), indicating the good barrier properties of external virgin polymer layers. Volatile and non-volatile compounds produced during irradiation affected the sensory properties of potable water after contact with packaging films. Taste transfer to water was observed mainly at higher doses and was more noticeable for multilayer structures containing recycled LDPE, even though differences were slight.

This study evaluated survival of Listeria spp. (four-strain mixture of Listeria innocua plus a non-virulent Listeria monocytogenes strain) and Escherichia coli O157:H7 strain ATCC 43888 during fermentation and ripening of Greek dry sausages formulated from meat and pork fat trimmings previously inoculated with ca. 6 log cfu g −1 of the target bacteria and then irradiated in frozen (−25 °C) blocks at doses of 0 (control), 2 or 4 kGy. Irradiation of the trimmings at 2 kGy reduced initial contamination of the sausage batter with Listeria and E. coli O157:H7 by 1.3 and 2.0 log cfu g −1 , respectively, while the corresponding reductions at 4 kGy were 2.4 and 5.5 log cfu g −1 , respectively. In fact, E. coli O157:H7 was eliminated by 4 kGy at formulation (day 0) as compared to 7 and 21 days of ripening in samples treated at 2 and 0 kGy, respectively. Despite the fact that irradiation assisted in faster declines of listeriae during fermentation, these bacteria showed a strong tailing during ripening, which was more pronounced in sausages irradiated at 4 kGy. As a consequence, survival of Listeria in 28-day sausages irradiated at 2 or 4 kGy was ca. 2 log cfu g −1 and similar ( P > 0.05) to that in non-irradiated samples. Irradiation showed promise for controlling E. coli O157:H7 and, to a lesser extent, L. monocytogenes in fermented sausages.

The combined effect of γ-irradiation and refrigeration on the shelf-life of vacuum-packaged sea bream (Sparus aurata) fillets was studied by monitoring the microbiological, chemical and sensory changes of non-irradiated and irradiated fish samples using low-dose irradiation doses of 1 and 3 kGy. Fish species such as sea bream and sea bass are very popular in the Mediterranean countries due to their high quality characteristics, and their preservation is a constant challenge given their extreme perishability. Irradiation (3 kGy) dramatically reduced populations of bacteria, namely, total viable counts (3 vs 7 log cfu g−1) for the non-irradiated samples, Pseudomonas spp (

Tensile testing, overall migration tests and sensory tests were used to evaluate the effects of gamma irradiation (5–60 kGy) on six commercial semirigid packaging materials. The monolayer and multilayer materials in sheet or bottle form were: polystyrene (PS), polypropylene (PP), polyvinyl chloride/high-density polyethylene (PVC/HDPE), polyethylene terepthalate (PET), HDPE/polyamide (HDPE/PA) and HDPE. In terms of mechanical strength, PET was the most radiation-resistant material, while the HDPE monolayer and multilayer showed some degradation after 60 kGy. PS was slightly affected after 30 kGy, whereas PP was severly degraded and became very brittle. Generally, there was no change in overall migration at lower doses; at higher doses migration from PP tended to increase, while migration from HDPE/PVC tended to decrease. Odor and taste transfer as well as discoloration were observed with most plastics, especially at higher doses, and it is concluded that these tests are a sensitive and important quality control tool for evaluating irradiated packaging materials.

The effect of gamma radiation (doses: 5, 10 and 30 kGy) on mechanical properties, gas and water vapour permeability and overall migration values into distilled water, 3% aqueous acetic acid and iso-octane was studied for a series of commercial multilayer flexible packaging materials based on coextruded polypropylene (PP), ethylene vinyl alcohol (EVOH), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyamide (PA) and Ionomer. The results showed that radiation doses of 5 and 10 kGy induced no statistically significant differences ( p >0.05) in all polymer properties examined. A dose of 30 kGy induced differences ( p p

Iron content in a satisfactory number of bottled and non-bottled white, rose and red Greek wines has been determined in this work. The wines analyzed were from various regions of Greece. Iron content was determined using two modified spectrophotometric methods. The classical method of Fe(III)-thiocyanate complex formation has been properly modified to work in a sulfuric acid medium, and in the presence of potassium persulfate (K 2 S 2 O 8 ) as an oxidant. The second method, involved the use of the compound 2-(5-nitro-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)-amino]-phenol disodium salt (Nitro-PAPS, C 17 H 19 O 6 N 5 SNa 2 ), known for its highly sensitive reaction with Fe(II). The experimental results of the two methods were found to be in good agreement with those obtained using the Atomic Absorption Spectroscopy (AAS) method. The proposed methods are rapid, accurate, simple, relatively inexpensive and can be used for all types of wine (white, rose and red). Therefore, they may be used for the iron assay in routine wine analyses, as an alternative to the AAS method. The values of iron content determined in the Greek white, rose and red wines were in the range 1.00 to 10.00 mg/l.

The effect of gamma irradiation on the natural microflora of whole salted vacuum-packaged trout at 4 and 10°C was studied. In addition, the effectiveness of gamma irradiation in controlling Listeria monocytogenes inoculated into trout was investigated. Irradiation at doses of 0.5 and 2 kGy affected populations of bacteria, namely, Pseudomonas spp., Brochothrix thermosfacta, lactic acid bacteria, H 2 S-producing bacteria typical of Shewanella putrefaciens, and Enterobacteriaceae, at both 4 and 10°C. This effect was more pronounced at the higher dose (2 kGy) and the lower temperature (4°C). Pseudomonads, H 2 S-producing bacteria typical of S. putrefaciens, and Enterobacteriaceae showed higher sensitivity to gamma irradiation than did the rest of the microbial species. Sensory evaluation did not show a good correlation with bacterial populations. On the basis of sensory odor scores, a shelf life of 28 days (2 kGy, 4°C) was obtained for salted vacuum-packaged freshwater trout, compared with a shelf life of 7 days for the unirradiated sample. Under the same conditions, the growth of L. monocytogenes inoculated into the samples was suppressed by 2 log cycles after irradiation (2 kGy) and storage for up to 18 days at 4°C. L'effet d'une irradiation gamma sur la microflore naturelle et sur Listeria monocytogenes dans des truites entieres salees conditionnees sous vide a 4 et 10°C est etudie. Le traitement affecte la microflore naturelle, principalement a des doses elevees (2 kGy) et a temperature faible (4°C). L'evaluation sensorielle ne montre pas une bonne correlation avec les populations bacteriennes. En se basant sur les resultats d'evaluation des odeurs, la duree de conservation du produit passe de 7 a 28 jours a 4°C pour les truites irradiees a 2kGy.

The moisture sorption isotherms of wheat and soy flours at 30 °C were constructed using the Novasina hygrometric technique. Wheat flour had a higher sorptive capacity than soy flour, as has previously been demonstrated using a chromatographic sorption technique. Good agreement was found between the Novasina and the static gravimetric methods. The difference between the two methods was of the order of 10.7% for wheat flour and 11.4% for soy flour. Subsequently, the flour samples were heat treated at 100 °C for 1 h and 150 °C for 2 h at various relative humidity environments (0.32

Thirty-three commercial thyme honeys (Thymus spp.) were characterized and classified according to geographical origin based on quality parameters, total phenolic content and radical scavenging activity. Quality parameter analysis included the determination of: pH, free, lactonic and total acidity, electrical conductivity, moisture, ash, hydroxymethylfurfural (HMF) content and diastase activity, using official methods of analysis. Finally, total phenolic content and % radical scavenging activity (%RSA) were estimated using the Folin–Ciocalteu and the 1,1-diphenyl-2-picryl-hydrazil [DPPH·] assay, respectively. Results showed that thyme honeys analyzed: (1) met all the quality criteria set by the EU; (2) showed variations in total phenolic content and radical scavenging activity; (3) possessed a special food character since total phenolic content was positively correlated with radical scavenging activity and (4) were successfully classified (correct prediction rate 93.9%) according to geographical origin applying chemometric analyses to the data collected. Practical Applications The present study highlights quality criteria and bioactive properties of Greek commercial thyme honeys, produced in different regional departments in Greece. Such parameters determined, give an enhanced functional food character to this product which can lead to consumers' awareness on nutritional foods of specific regional origin. In addition, the use of chemometric analyses on quality parameters, total phenolic content and radical scavenging activity proved to be a strong key for correct geographical classification of Greek commercial thyme honey.

The water sorption isotherms of wheat and soy flour were constructed at 30°C using the gravimetric (static), inverse gas chromatographic (IGC) and computerised inverse gas chromatographic (CIGC) techniques. The times required for the construction of a single sorption isotherm by these methods were approximately 3 weeks, 2 days and 3 hours, respectively. Good agreement was observed between sorption isotherms for wheat and soy flour obtained with the IGC and static methods. Differences between the two methods were in the order of 7·5% for wheat flour and 12% for soy flour. The respective differences between the static and CIGC methods were in the order of 18·5% for wheat flour and 12% for soy flour. The experimental data were fitted successfully to both the BET and GAB model equations, and monolayer ( V m ) and sorption constant ( C ) values were calculated for all three methods. It is proposed that both the IGC and GIGC techniques may be used reliably as alternatives to the static method industrial applications involving flour-based products where time is a critical factor.

The aim was to study the effect of electron-beam irradiation on the production of radiolysis products and sensory changes in experimental high-barrier packaging films composed of polyamide (PA), ethylene-vinyl alcohol (EVOH) and low-density polyethylene (LDPE). Films contained a middle buried layer of recycled LDPE, while films containing 100% virgin LDPE as the middle buried layer were taken as controls. Irradiation doses ranged between zero and 60 kGy. Generally, a large number of radiolysis products were produced during electron-beam irradiation, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food 'cold pasteurization'). The quantity of radiolysis products increased with irradiation dose. There were no significant differences in radiolysis products identified between samples containing a recycled layer of LDPE and those containing virgin LDPE (all absorbed doses), indicating the 'functional barrier' properties of external virgin polymer layers. Sensory properties (mainly taste) of potable water were affected after contact with irradiated as low as 5 kGy packaging films. This effect increased with increasing irradiation dose.

Three types of ionizing radiation are used in commercial radiation to process products such as foods and medical and pharmaceutical devices: radiation from high-energy gamma rays, X-rays, and accelerated electrons. In accordance with the Codex General Standard for Irradiated Foods, only these ionizing rays are authorized to be used in food irradiation applications. These types of radiation are called ‘‘ionizing’’ because their energy is high enough to dislodge electrons from atoms and molecules and to convert them to electrically charged particles called ions. Ionizing radiation may originate from different sources: gamma rays, electron beams, and X-rays or decelerating rays. Gamma rays and X-rays form part of the electromagnetic spectrum, like radio waves, microwaves, ultraviolet, and visible light rays. Gamma rays and X-rays are in the short wave length, high-energy region of the spectrum. Both gamma and X-rays can penetrate foods to a depth of several decade centimeters. Energies from the previously mentioned radiation sources are too low to induce radioactivity in any material, including food.

The technique of inverse gas chromatography (IGC) was used to investigate the thermodynamic miscibility (compatibility) of low molecular weight PVC-poly(adipate ester) plasticizer mixtures. The polymer-plasticizer thermodynamic interaction parameters were determined from chromatographic retention data for various low molecular weight volatile solutes (probes) on stationary phase mixtures which covered the entire composition range for each component. Experiments were carried out in the temperature range of 90 to 110°C. The Flory-Huggins interaction parameter (χ+23) values were found to be dependent on the chemical nature of the probes, the temperature, and the composition of the mixed phase. The results predict a relatively high polymer-plasticizer compatibility for a wide range of polymer-plasticizer mixtures (up to approx. 70 wt.-% of plasticizer). Results were also compared to our own previous data using high molecular weight PVC. Die Technik der inversen Gaschromatographie (IGC) wurde zur Untersuchung der thermodynamischen Mischbarkeit (Vertraglichkeit) von niedermolekularem Poly(vinylchlorid) (PVC) mit einem Poly(adipinsaureester) als Weichmacher angewendet. Die thermodynamischen Polymer-Weichmacher-Wechselwirkungsparameter wurden aus den chromatographischen Retentionsdaten verschiedener, niedermolekularer fluchtiger Substanzen als mobile Phase auf einer stationaren Phase aus Polymer-Weichmacher-Mischungen, die sich uber den gesamten moglichen Zusammensetzungsbereich erstreckten, ermittelt. Die Untersuchungen wurden im Temperaturbereich von 90 bis 110°C durchgefuhrt. Der Flory-Huggins-Wechselwirkungsparameter (χ+23) hangt dabei im wesentlichen von der chemischen Natur der als “Sonde” verwendeten fluchtigen Substanz (mobile Phase), von der Temperatur und von der Zusammensetzung der Polymer-Weichmacher-Mischung (stationare Phase) ab. Die Ergebnisse deuten auf eine relativ gute Polymer-Weichmacher-Vertraglichkeit uber einen weiten Zusammensetzungsbereich (bis ca. 70 Gew.-% Weichmacher) hin; die Vertraglichkeit ist damit besser als bei fruheren Untersuchungen mit hochmolekularem PVC.

The technique of inverse gas chromatography was applied to study the miscibility (compatibility) of the system of PVC with epoxidized soybean oil (ESO). The PVC-ESO thermodynamic interaction parameters, χ + 23 , were determined from the measured retention data for various vapour-phase “probes” in stationary phase mixtures of the components covering the entire composition range. Experiments were run in the range 90–110°C. In accordance with previous studies on polymer-polymer and polymer-plasticizer blends, the interaction parameters were found to be dependent on the temperature, the chemical nature of the probe and the blend composition. χ + 23 values were mostly negative or slightly positive up to 0.40 weight fraction of ESO, indicating relatively high compatibility of PVC and ESO for this range of compositions. They then increased with increasing plasticizer content and, at ca 0.70 weight fraction of ESO, exceeded 0.5 which is considered as the “compatibility limit value”.

The moisture sorption isotherms of apple and citrus pectins using a computerised inverse gas chromatographic (IGC) method were constructed at 25, 30, 40 and 50°C. Sorption isotherm data are calculated from a single injection of water with the aid of a personal computer and a program developed to perform data handling. Thus sorption isotherms are constructed in < 3 h. Good agreement was observed between moisture sorption isotherms of apple and citrus pectins obtained with the computerised IGC method and the gravimetric static method.

The compatibilities of the systems poly(vinylidene chloride-vinyl chloride 80:20)/polyadipate ester and poly(vinylidene chloride-vinyl chloride 80:20)/tri-isononyl trimellitate have been studied in the range 90–110°C using inverse gas chromatography (IGC). The retention behaviour of the polymer/plasticizer mixtures covering the entire composition range for each component was characterized for 10 probes of different chemical nature. In agreement with previous work, the IGC-derived interaction parameters (X+23) showed an apparent dependence on the chemical nature of the probe, blend composition and temperature. The results predict good polymer/plasticizer compatibility up to c. 0–40 weight fraction of plasticizer for poly(vinylidene chloride-vinyl chloride 80:20)/polyadipate ester blends and to c. 0.50 for poly(vinylidene chloride-vinyl chloride 80:20)/tri-iso-nonyl trimellitate blends.

The technique of inverse gas chromatography has been applied to a thermodynamic study of the miscibility (compatibility) of PVC and a polymeric (polyadipate ester) plasticizer. A number of organic solvents (probes) were used to evaluate the Flory-Huggins parameters for the PVC-plasticizer interaction in stationary phase mixtures of the two components covering the entire composition range for each component (0–100%). Experiments were carried out in the range 90–120°. The interaction parameter values were found to be dependent on the chemical nature of the probes, the temperature and the composition of the mixed (binary) phase. The results predict good polymer-plasticizer compatibility for a wide range of the above mixture (up to ca 0.55 weight fraction of plasticizer).

Changes in microbiological and physicochemical quality attributes resulting from the use of irradiation in the production of Greek dry fermented sausage were investigated as a function of fermentation/ripening time. Results showed that irradiating meat/fat trimmings at 2 or 4 kGy prior to sausage production eliminated natural contamination with Listeria spp., and reduced pseudomonads, enterococci and pathogenic staphylococci, and enterobacteria, to less than 2 and I log cfu g(-1), respectively. Pseudomonads were very sensitive (> 3.4 log reduction) to either radiation dose. Yeasts were the most resistant followed by inherent lactic acid bacteria; their reductions on the trimmings were radiation dose-dependent. Residual effects of irradiation were noted against enterococci, but not against gram-negatives which died off fast during fermentation even in non-irradiated samples. Growth of the starter bacteria, Lactobacillus pentosus and Staphylococcus carnosus, inoculated in the sausage batters post-irradiation was unaffected by the 2 or 4 kGy pre-treatment of the trimmings. Irradiation had little or no effect at the end of ripening period (28 days) on pH, moisture content and color (parameters L*, a*, and b*). Changes in TBA values were small but statistically significant with irradiated samples having higher TBA values than control samples. (c) 2006 Elsevier Ltd. All rights reserved. Meat Sci

The determination of commercial plasticizers (di-(2-ethylhexyl)adipate (DEHA) and acetyl tributyl citrate (ATBC)) in aqueous solutions is described. The newly proposed technique of applying microwaves to cloud point extracts in order to enable combination with gas chromatographic analysis has been used for this purpose. Both plasticizers were entrapped in the micelles of the non-ionic surfactant Triton X-114 and removed from the bulk phase by centrifugation. Micellization was enhanced by increasing the ionic strength of the solution with concentrated NaCl. Extraction recoveries of the proposed method were over 95% for water and 3% (w/v) aqueous acetic acid and over 85% for 10% (v/v) aqueous ethanol, respectively. The calibration curves obtained, following the proposed methodology have a linear range between 50 and 2000 microg/L for each analyte while the detection limits were as low as 15 and 19 microg/L for DEHA and ATBC, respectively, with an RSD below 5% even for low concentrations. As an analytical demonstration the proposed methodology was applied for the determination of the migration levels of the selected plasticizers from a PVC food packaging film into aqueous simulants.