Evaluation of 2-alkylcyclobutanones in irradiated cured pork products during vacuum-packed storage

The 2-Alkylcyclobutanones (2-ACBs) content was determined in three Italian cured pork products (salame Milano, coppa, and pancetta) irradiated at different targeted irradiation doses (2, 5, and 8 kGy) during vacuum-packed storage. Among 2-ACBs, three different compounds were investigated, namely, 2-dodecylcyclobutanone, 2-tetradecylcyclobutanone, and 2-(tetradec-5'-enyl)cyclobutanone. 2-ACBs were absent from the nonirradiated samples, whereas their content increased with irradiation dose. Their presence was recorded occasionally at 2 kGy and constantly at higher irradiation doses (5 and 8 kGy). The plot of 2-ACBs content against targeted irradiation doses showed an exponential relationship. The effect of vacuum-packed storage time on the 2-ACBs content was dependent on the irradiation dose. During vacuum-packed storage for up to 60 days, the 2-ACBs content remained unchanged in the cured pork products irradiated at 2 and 5 kGy, whereas a significant increase was observed in the pork products irradiated at 8 kGy.     

Deposition of gold mining tailings in tropical soils: metal pollution and toxicity to earthworms

Journal of Soils and Sediments - This study consists of the evaluation of metals acute toxicity levels taking into consideration a hypothetic scenario of dam breaking and land deposition of two...     

Adsorption of flavonoids on resins: hesperidin

Adsorption of hesperidin from aqueous solutions on styrene-divinylbenzene (SDVB) and acrylic resins was investigated at different pH values (1.5-5.5) and temperatures (10-40 degrees C). Adsorption was not affected by pH variation, whereas it increased on increasing temperature for the SDVB resins and remained substantially unchanged for the acrylic ones. The different behavior of the two types of resins was ascribed to the different wetting, because of their hydrophobic or partially hydrophilic properties, respectively. The equilibrium data at 20 degrees C were determined on 13 commercial resins displaying a wide range of surface areas (S(A), 330-1200 m(2)/g) and pore radii (P(R), 20-260 A). Data were well fitted to the Freundlich isotherm, and its parameters were used to compare the adsorption capacity of different resins. The most effective resin is a SDVB copolymer with the largest S(A) (1200 m(2)/g) and an intermediate P(R) (90 A). The Freundlich constants (K(F)) were rationalized in terms of a two parameter equation, including S(A) and P(R) as independent variables. The adsorption constant increased on increasing both S(A) and P(R) for the resins having P(R) 相似文献   

A molecular basis for natural selection at the timeless locus in Drosophila melanogaster

Diapause is a protective response to unfavorable environments that results in a suspension of insect development and is most often associated with the onset of winter. The ls-tim mutation in the Drosophila melanogaster clock gene timeless has spread in Europe over the past 10,000 years, possibly because it enhances diapause. We show that the mutant allele attenuates the photosensitivity of the circadian clock and causes decreased dimerization of the mutant TIMELESS protein isoform to CRYPTOCHROME, the circadian photoreceptor. This interaction results in a more stable TIMELESS product. These findings reveal a molecular link between diapause and circadian photoreception.     

Factors that contribute to the mycoparasitism stimulus in Trichoderma atroviride strain P1

Trichoderma atroviride strain P1 has been used extensively to study the mycoparasitic mechanisms in the interaction between plant pathogenic host and beneficial antagonistic fungi. Mutants of P1 containing the green fluorescent protein (gfp) or glucose oxidase (gox) reporter systems and different inducible promoters (from the exochitinase nag1 gene, or the endochitinase ech42 gene of P1) were used to determine the factors that activate the biocontrol gene expression cascade in the antagonis…     

Phloroglucinol from phlorin hydrolysis for testing quality of commercial orange juices and beverages

The European Association of Juices and Nectars Producers (AIJN) is evaluating the opportunity to introduce the content of phlorin (3,5-dihydroxyphenyl beta-D-glucopyranoside), a peel marker for oranges, as a parameter for testing the quality of orange juices. Because of the lack of a commercial standard of phlorin and its laborious isolation procedures, in this contribution is developed a simple and reliable method for measuring the phlorin level as the corresponding aglycon phloroglucinol, obtained after a total enzymatic hydrolysis of the sample. The method was applied to the quantification of phloroglucinol in several industrial and commercial blond and pigmented orange juices and beverages based on 12% orange juice. Under the same extraction procedure, the phloroglucinol content in the pigmented juices was higher than in the blond ones. No significant difference was obtained between not from concentrate juices and reconstituted from concentrate juices. The marker amount increases in the highly processed orange fruits and in the byproducts of citrus processing due to the contact of the juice with the albedo, which is the major source of phlorin. In orange-based beverages the phloroglucinol content revealed a large heterogeneity and a poor quality of the raw juices used.     

In vivo bioinsecticidal activity toward Ceratitis capitata (fruit fly) and Callosobruchus maculatus (cowpea weevil) and in vitro bioinsecticidal activity toward different orders of insect pests of a trypsin inhibitor purified from tamarind tree (Tamarindus indica) seeds

A proteinaceous inhibitor with high activity against trypsin-like serine proteinases was purified from seeds of the tamarind tree (Tamarindus indica) by gel filtration on Shephacryl S-200 followed by a reverse-phase HPLC Vidac C18 TP. The inhibitor, called the tamarind trypsin inhibitor (TTI), showed a Mr of 21.42 kDa by mass spectrometry analysis. TTI was a noncompetitive inhibitor with a Ki value of 1.7 x 10(-9) M. In vitro bioinsecticidal activity against insect digestive enzymes from different orders showed that TTI had remarkable activity against enzymes from coleopteran, Anthonomus grandis (29.6%), Zabrotes subfasciatus (51.6%), Callosobruchus maculatus (86.7%), Rhyzopertha dominica(88.2%), and lepidopteron, Plodia interpuncptella (26.7%), Alabama argillacea (53.8%), and Spodoptera frugiperda (75.5%). Also, digestive enzymes from Diptera, Ceratitis capitata (fruit fly), were inhibited (52.9%). In vivo bioinsecticidal assays toward C. capitata and C. maculatus larvae were developed. The concentration of TTI (w/w) in the artificial seed necessary to cause 50% mortality (LD50) of larvae was 3.6%, and that to reduce mass larvae by 50.0% (ED50) was 3.2%. Furthermore, the mass C. capitata larvae were affected at 53.2% and produced approximately 34% mortality at a level of 4.0% (w/w) of TTI incorporated in artificial diets.