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21.
Greece currently has no national forest certification standard.This paper explains how a draft forest management standard forGreece was developed to be compatible with both the Forest StewardshipCouncil and the Programme for the Endorsement of Forest Certificationschemes requirements. The draft standard was tested in two contrastingforest areas to investigate its ease of operation, to indicatenecessary refinements to the standard and to reveal major areasof weakness in current forest management practices. Field testingshowed that the standard was operationally efficient and thatrelatively few changes to the standard were necessary. Majorweaknesses in current management practices were identified asbreaches of health and safety, poor training of forest workersand inadequate consultation with stakeholders. 相似文献
22.
Use of natural and modified cyclodextrins as inhibiting agents of peach juice enzymatic browning 总被引:1,自引:0,他引:1
López-Nicolas JM Pérez-López AJ Carbonell-Barrachina A García-Carmona F 《Journal of agricultural and food chemistry》2007,55(13):5312-5319
Although cyclodextrins (CDs) have been successfully used as antibrowning agents in different fruit juices, no research has studied the effect of these compounds on enzymatic browning in peach juice. In this paper, the color of fresh peach juice was evaluated in the presence of two types of natural (alpha-CD and beta-CD) and a modified (maltosyl-beta-CD) CD, and the effectiveness of these compounds as browning inhibitors was determined using the color space CIELAB system. Moreover, to clarify the mechanism by which CDs inhibit peach juice enzymatic browning, the process was kinetically modeled in the absence and presence of CDs using a colorimetric method; the apparent complexation constants between the mixtures of diphenols present in peach juice and some types of CD were calculated. The results show that the highest affinity constant was presented by alpha-CD (Kc = 18.31 mM-1) followed by maltosyl-beta-CD (Kc = 11.17 mM-1), whereas beta-CD was incapable of inhibiting peach juice enzymatic browning. Keywords: Cyclodextrin; browning; peach; juice; color; polyphenol oxidase. 相似文献
23.
Occurrence of naturally acetylated lignin units 总被引:2,自引:0,他引:2
Del Río JC Marques G Rencoret J Martínez AT Gutiérrez A 《Journal of agricultural and food chemistry》2007,55(14):5461-5468
This work examines the occurrence of native acetylated lignin in a large set of vascular plants, including both angiosperms and gymnosperms, by a modification of the so-called Derivatization Followed by Reductive Cleavage (DFRC) method. Acetylated lignin units were found in the milled wood lignins of all angiosperms selected for this study, including mono- and eudicotyledons, but were absent in the gymnosperms analyzed. In some plants (e.g., abaca, sisal, kenaf, or hornbeam), lignin acetylation occurred at a very high extent, exceeding 45% of the uncondensed (alkyl-aryl ether linked) syringyl lignin units. Acetylation was observed exclusively at the gamma-carbon of the lignin side chain and predominantly on syringyl units, although a predominance of acetylated guaiacyl over syringyl units was observed in some plants. In all cases, acetylation appears to occur at the monomer stage, and sinapyl and coniferyl acetates seem to behave as real lignin monomers participating in lignification. 相似文献
24.
Sanches Filho PJ Rios A Valcarcel M Melecchi MI Caramão EB 《Journal of agricultural and food chemistry》2007,55(3):603-607
In this paper, the use of supercritical fluid extraction (SFE) and micellar electrokinetic capillary chromatography (MEKC) is proposed for the complete analysis of volatile nitrosamines in sausages. The extraction fluid used was CO2 and variables such as density, temperature of thimbles, extraction time, modifier, fluid flow, and kind of traps were investigated. Several experiments were carried out to obtain the most favorable conditions for analysis of volatile nitrosamines in sausages. The recoveries ranged from 21 to 82% for the five nitrosamines studied. The optimal condition of extraction was 0.2 g of sample fortified with 10 mg/kg, using dynamic extraction during 20 min and with adsorbent Florisil in the trap. The solvent selected for the elution of the analytes was methanol. 相似文献
25.
Pérez-López AJ López-Nicolas JM Núñez-Delicado E Del Amor FM Carbonell-Barrachina AA 《Journal of agricultural and food chemistry》2007,55(20):8158-8164
Consumers demand organic products because they believe they are more flavorful and respectful to the environment and human health. The effects of conventional, integrated, and organic farming, grown in a controlled greenhouse, on color, minerals, and carotenoids of sweet pepper fruits ( Capsicum annuum), cv. Almuden, were studied. Experimental results proved that organic farming provided peppers with the highest (a) intensities of red and yellow colors, (b) contents of minerals, and (c) total carotenoids. Integrated fruits presented intermediate values of the quality parameters under study, and conventional fruits were those with the lowest values of minerals, carotenoids, and color intensity. As an example, the concentrations of total carotenoids were 3231, 2493, and 1829 mg kg (-1) for organic, integrated, and conventional sweet peppers, respectively. Finally, organic red peppers could be considered as those having the highest antioxidant activity of all studied peppers (agricultural farming and development stage). 相似文献
26.
After the decline of the Bovine Spongiform Encephalopathy (BSE) epidemic in Great Britain (GB), scrapie remains the most prevalent animal Transmissible Spongiform Encephalopathy (TSE) present in GB. A number of control measures have been implemented for classical scrapie, and since 2005 there has been a large reduction in the number of observed cases. The objective of this study is to estimate two measures of disease frequency using up to date surveillance data collected during and after the implementation of different control measures established since 2004, and breeding for resistance schemes that ran from 2001 until 2009. This would enable an assessment of the effectiveness of both the breeding for resistance programme and the compulsory eradication measures in reducing the prevalence of scrapie in GB. Evaluation of the sensitivity of the rapid post-mortem test for scrapie indicated that it detected scrapie in the last 25% of the incubation period. A back-calculation model was developed to estimate the prevalence of infection at animal and flock-level. The results of the model indicated a mean drop of infection prevalence of 31% each year, leading to a 90% drop in infection prevalence between 2005, with an estimate of 5737 infected sheep in GB in 2012. 相似文献
27.
Miguel Mellado Angel M. Garcia Beatriz Arellano-Reynoso Efren Diaz-Aparicio Jose E. Garcia 《Tropical animal health and production》2014,46(2):391-397
The aim of this research was to study if seropositivity for brucellosis in vaccinated cows against this disease hampers reproductive performance and milk production in high-yielding Holstein cows. For this purpose 1,026 healthy cows and 372 cows seropositive for brucellosis were enrolled in this study. Cows positive to card test and subsequently to the rivanol test were further subjected to the radial immunodiffusion (RID) test. It was found that only 11 % of the presumably infected cows by brucellosis screening tests were really infected with this disease. The reproductive performance of the group of cows with 11 % Brucella-infected animals was not impaired; overall pregnancy rate did not differ between seropositive and healthy cows (30.9 vs. 29.6 %). The abortion rates were similar between seropositive cows (5.3 %) and seronegative animals (6.9 %). Cows in the herd with 11 % Brucella-infected animals produced significantly more milk than unaffected cows over a 305-day lactation (10,684?±?1,720 vs. 10,345?±?1,736; mean ± SD; P?<?0.05). It was concluded that in dairy herds vaccinated against brucellosis with both 19 and RB51 strains, supplemental tests such as RID need to be conducted on all reactors in order to maintain diagnostic accuracy. These results also indicate that 11 % animal prevalence of brucellosis did not exert a detrimental effect on 305-day milk yield and reproductive performance in high milk-yielding Holstein cows. 相似文献
28.
Valeria F. Del Coco María Alejandra Córdoba Gladys Bilbao Pinto de Almeida Castro Juan Angel Basualdo Mónica Santín 《Veterinary parasitology》2014,199(1-2):112-115
Fecal specimens were obtained from a total of 70 dairy calves less than two months old on 11 municipalities in Buenos Aires, Argentina. After removal of fecal debris by sieving and sucrose flotation, specimens were subjected to PCR to detect the presence of Enterocytozoon bieneusi. PCR revealed a 14.3% of prevalence for E. bieneusi with 10 positive calves from 7 municipalities. Gene sequence analysis conducted in all samples positives by PCR revealed the presence of six genotypes; four previously reported in cattle as well as humans (D, I, J, and BEB4), one never reported in cattle before but previously reported in humans (EbpC), and one novel genotype (BEB10). These results constitute the first molecular characterization of E. bieneusi in Argentina, and suggest a potential risk of zoonotic transmission in this area. 相似文献
29.
While numerous studies have evaluated intestinal phytase activity in terrestrial monogastric species, little work has been
conducted investigating the enzyme's activity in finfish. This experiment was conducted to determine if hybrid striped bass
Morone saxatilis × M. chrysops possess intestinal phytase activity, and to perform a preliminary characterization of this activity in terms of pH, metal
ion dependence and substrate kinetics. Hybrid bass do exhibit low levels of intestinal phytase activity. The activity has
an acidic pH optimum between 3.5 and 4.5. Low concentrations of Mn2+ slightly enhance this activity. The divalent cations Mg2+ and Zn2+ were shown to either have no effect on the enzyme activity or to be inhibitory, particularly at high concentrations. The
present results indicate that intestinal phytase activity in hybrid bass does follow Michaelis-Menten kinetics, with estimated
Km and Vmax values of 2.5 mM phytate and 4.8 units mg−1 protein, respectively. The physiologic significance of the enzyme's presence in hybrid striped bass is questionable due to
the low activity as compared to terrestrial monogastrics, the acidic pH optimum and the low affinity the enzyme appears to
have for phytate. These observations also raise the question of whether the intestinal phytase activity detected in hybrid
bass is merely a manifestation of non-specific acid phosphatase activity. Further investigation is needed to determine the
practical significance of phytase activity in hybrid bass in terms of phytate phosphorus utilization. Additional experiments
should also be conducted which evaluate intestinal phytase activity in other important aquacultured finfish species.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
30.