Quantification of selected volatile constituents and anions in Mexican Agave spirits (Tequila, Mezcal, Sotol, Bacanora)   总被引：4，自引：0，他引：4  

Lachenmeier DW  Sohnius EM  Attig R  López MG 《Journal of agricultural and food chemistry》2006,54(11):3911-3915

A large collection (n = 95) of Mexican Agave spirits with protected appellations of origin (Tequila, Mezcal, Sotol, and Bacanora) was analyzed using ion and gas chromatography. Because of their production from oxalate-containing plant material, all Agave spirits contained significant concentrations of oxalate (0.1-9.7 mg/L). The two Tequila categories ("100% Agave" and "mixed") showed differences in the methanol, 2-/3-methyl-1-butanol, and 2-phenylethanol concentrations with lower concentrations in the mixed category. Mezcal showed no significant differences in any of the evaluated parameters that would allow a classification. Sotol showed higher nitrate concentrations and lower 2-/3-methyl-1-butanol concentrations. Bacanora was characterized by exceptionally high acetaldehyde concentrations and a relatively low ethyl lactate content. The methanol content was the most problematic compound regarding the Mexican standards: two Tequilas (4%), five Sotols (31%), and six Bacanoras (46%) had levels above the maximum methanol content of 300 g/hL of alcohol. In conclusion, the composition of Mexican Agave spirits was found to vary over a relatively large range.  相似文献   

Epochal evolution shapes the phylodynamics of interpandemic influenza A (H3N2) in humans     

Koelle K  Cobey S  Grenfell B  Pascual M 《Science (New York, N.Y.)》2006,314(5807):1898-1903

Human influenza A (subtype H3N2) is characterized genetically by the limited standing diversity of its hemagglutinin and antigenically by clusters that emerge and replace each other within 2 to 8 years. By introducing an epidemiological model that allows for differences between the genetic and antigenic properties of the virus's hemagglutinin, we show that these patterns can arise from cluster-specific immunity alone. Central to the formulation is a genotype-to-phenotype mapping, based on neutral networks, with antigenic phenotypes, not genotypes, determining the degree of strain cross-immunity. The model parsimoniously explains well-known, as well as previously unremarked, features of interpandemic influenza dynamics and evolution. It captures the observed boom-and-bust pattern of viral evolution, with periods of antigenic stasis during which genetic diversity grows, and with episodic contraction of this diversity during cluster transitions.  相似文献   

Effect of tocopherols in the antioxidative activity of oxidized lipid-amine reaction products     

Hidalgo FJ  León MM  Zamora R 《Journal of agricultural and food chemistry》2007,55(11):4436-4442

Phosphatidylethanolamine (PE), phosphatidylcholine (PC), lysine (Lys), and mixtures of them were tested for antioxidative activity in a tocopherol-stripped olive oil (TSO) and the same oil after addition of 250 microg of alpha-tocopherol g of oil/(tocopherol-added olive oil, TAO) to evaluate the role of tocopherol in the antioxidant activity of oxidized lipid-amine products. Neither PE nor PC nor Lys protected TSO when tested alone, but both PE and Lys increased the induction period (IP) of TAO. On the contrary, PE/Lys and PC/Lys mixtures, but not PC/PE mixtures, protected both TSO and TAO. These results were a consequence of both the formation of oxidized lipid-amine products, which were determined by gas chromatography-mass spectrometry after their conversion into volatile derivatives, and a synergism between alpha-tocopherol and the produced compounds. These results were confirmed by analyzing the antioxidative activity of two of the produced carbonyl-amine products: 6-amino-2-(1H-pyrrol-1-yl)hexanoic acid (1) and 2,3-dipalmitoylpropyl 2-(1H-pyrrol-1-yl)ethyl phosphate (2). The hydrophilic compound 1 was more antioxidant than the analogous lipophilic compound 2, and this antioxidative activity was observed in TAO and not in TSO. All these results suggested that antioxidative activity of carbonyl-amine products may be greatly increased with the addition of tocopherols, and those products derived from Lys are more antioxidant in bulk oils than those derived from PE.  相似文献   

Analysis of the genetic control of β-carotene and <Emphasis Type="SmallCaps">l</Emphasis>-ascorbic acid accumulation in an orange-brownish wild cherry tomato accession     

Ana Maria Adalid  Salvador Roselló  Mercedes Valcárcel  Fernando Nuez 《Euphytica》2012,184(2):251-263

An additive-dominance, additive × additive (ADAA) and genotype × environment interaction mix model was used to study the genetic control of β-carotene and l-ascorbic acid in six basic generations (P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂) of tomato derived from the cross CDP8779 accession (Solanum lycopersicum L.) × CDP4777 accession (S. lycopersicum var. cerasiforme). The study was performed in two environments: (1) open field; (2) protected environment, consisting of hydroponic cultivation in a glasshouse. The results indicate that β-carotene accumulation was mainly additive (32.2% of the genetic component), with a small dominant component (4.2%) and an important additive × environment interaction contribution (63.6%). In target environments with moderate to high temperatures and no limiting radiation, this the expression additive × environment interaction could substantially enhance the β-carotene content. This trait showed also a high narrow-sense heritability (h ² = 0.62). Ascorbic acid accumulation was also mainly additive (61.7% of the genetic component), with a minor additive epistatic component (21.5%). This epistatic effect caused a negative heterosis that reduced the positive main additive effect. Nevertheless, in the described target environments, the additive × environment interaction contribution (16.8%) may enhance the ascorbic acid content and compensate for the negative heterosis effect. The total narrow-sense heritability of this trait can be considered useful (h ² = 0.52). In conclusion, the CDP4777 accession is a very interesting donor parent for the joint improvement of β-carotene (without diminishing lycopene content) and ascorbic acid content in commercial nutraceutical tomato breeding programmes; the F₁ hybrids derived from this accession showed nearly 450% of the commonly reported average β-carotene content and close to 130% of the ascorbic acid content of the female parent.  相似文献   

Multivariate analysis of FTIR and ion chromatographic data for the quality control of tequila     

Lachenmeier DW  Richling E  López MG  Frank W  Schreier P 《Journal of agricultural and food chemistry》2005,53(6):2151-2157

Principal component analysis (PCA) was applied to the chromatographic and spectroscopic data of authentic Mexican tequilas (n = 14) and commercially available samples purchased in Mexico and Germany (n = 24). The scores scatter plot of the first two principal components (PC) of the anions chloride, nitrate, sulfate, acetate, and oxalate accounting for 78% of the variability allowed a classification between tequilas bottled in Mexico and overseas; however, no discrimination between tequila categories was possible. Mexican products had a significantly (p = 0.0014) lower inorganic anion concentration (range = 1.5-5.1 mg/L; mean = 2.5 mg/L) than the products bottled in the importing countries (range = 3.3-62.6 mg/L; mean = 26.3 mg/L). FTIR allowed a rapid screening of density and ethanol as well as the volatile compounds methanol, ethyl acetate, propanol-1, isobutanol, and 2-/3-methyl-1-butanol using partial least-squares regression (precisions = 5.3-29.3%). Using PCA of the volatile compounds, a differentiation between tequila derived from "100% agave" (Agave tequilana Weber var. azul, Agavaceae) and tequila produced with other fermentable sugars ("mixed"tequila) was possible. The first two PCs describe 89% of the total variability of the data. Methanol and isobutanol influenced the variability in PC1, which led to discrimination. The concentrations of methanol and isobutanol were significantly higher (methanol, p = 0.004; isobutanol, p = 0.005) in the 100% agave (methanol, 297.9 +/- 49.5; isobutanol, 251.3 +/- 34.9) than in the mixed tequilas (methanol, 197.8 +/- 118.5; isobutanol, 151.4 +/- 52.8).  相似文献   

Effect of different soaking solutions on nutritive utilization of minerals (calcium,phosphorus, and magnesium) from cooked beans (Phaseolus vulgaris L.) in growing rats     

Nestares T  Barrionuevo M  López-Frías M  Vidal C  Urbano G 《Journal of agricultural and food chemistry》2003,51(2):515-520

The effects of the commonly used processing techniques of soaking (at different pH values) and cooking on the digestive and nutritive utilization of calcium, phosphorus, and magnesium from common beans (Phaseolus vulgaris L.) were studied. Before the cooking step, the beans were soaked in solutions of acid (2.6 and 5.3) or basic (8.4) pH. Chemical and biological methods were used to determine nutritional parameters in growing rats, and the fiber content of the beans was established. As the pH of the soaking solution increased, so did mineral absorption and the apparent digestibility coefficient, which reached suitable values for growing rats, due to the reduced losses of soluble minerals and the increased food intake. Metabolic utilization also improved with increased pH of the soaking solution, although the values were, in general, low as a result of urinary losses under the experimental conditions. For the experimental period of 10 days, the femur and the muscle seem to be good metabolic indicators for calcium, but not for phosphorus or magnesium. The increased amount of cellulose in the soaked seed did not have a negative effect on the digestive utilization of minerals.  相似文献   

Effect of pentosanase and oxidases on the characteristics of doughs and the glutenin macropolymer (GMP)     

Primo-Martín C  Valera R  Martínez-Anaya MA 《Journal of agricultural and food chemistry》2003,51(16):4673-4679

Rheological characteristics of dough and glutenin macropolymer (GMP) extracted thereof were investigated. Three single enzymes, pentosanase (PP), glucoseoxidase (GLZ), and laccase (LAC), and their combinations were used. GLZ gave the least extensible and most resistant dough, and pentosanase/glucoseoxidase (PPGLZ) resulted in dough with improved extensibility. The enzymes improved gluten quality. The glutenin macropolymer (GMP) was characterized in terms of wet weight, protein content, pentosan association, and dynamic rheological properties. Enzymatic addition decreased the wet weight of GMP but increased the protein content. PP decreased the content of pentosans on the GMP, but single oxidases increased the content of pentosans associated with GMP. PP did not modify the elastic modulus (G') of the GMP, whereas GLZ increased G' by increasing the polymerization of proteins and LAC diminished G'. The combination PPGLZ produced a synergic increase of G'.  相似文献   

A Wind Tunnel Study of Airflow through Horticultural Crops: Determination of the Drag Coefficient   总被引：2，自引：0，他引：2  

F.D. Molina-Aiz  D.L. Valera  A.J. lvarez  A. Madueo 《Biosystems Engineering》2006,93(4):447-457

  相似文献   

Effects of extrusion, boiling, autoclaving, and microwave heating on lupine allergenicity   总被引：1，自引：0，他引：1  

Alvarez-Alvarez J  Guillamón E  Crespo JF  Cuadrado C  Burbano C  Rodríguez J  Fernández C  Muzquiz M 《Journal of agricultural and food chemistry》2005,53(4):1294-1298

Lupine flour has been reported as a causative agent of allergic reactions. However, the allergenicity of lupine after thermal processing is not well-known. For this purpose, the allergenic characteristics of lupine seeds after boiling (up to 60 min), autoclaving (121 degrees C, 1.18 atm, up to 20 min and 138 degrees C, 2.56 atm, up to 30 min), microwave heating (30 min), and extrusion cooking were studied. The IgE-binding capacity was analyzed by IgE-immunoblotting and CAP inhibition using a serum pool from 23 patients with lupine-specific IgE. Skin testing was carried out in four patients. An important reduction in allergenicity after autoclaving at 138 degrees C for 20 min was observed. IgE antibodies from two individual sera recognized bands at 23 and 29 kDa in autoclaved samples at 138 degrees C for 20 min. Autoclaving for 30 min abolished the IgE binding to these two components. A previously undetected band at 70 kDa was recognized by an individual serum. Therefore, prolonged autoclaving might have an important effect on the allergenicity of lupine with the majority of patients lacking IgE reactivity to these processed samples.  相似文献   

Soil arthropod abundance under conventional and no tillage in a Mediterranean climate     

Estefanía Rodríguez  Francisco Javier Fernndez-Anero  Pablo Ruiz  Mercedes Campos 《Soil & Tillage Research》2006,85(1-2):229-233

We have studied the impact on arthropod populations of conventional tillage and no-tillage systems in maize. Two different corn–weed control programs were assayed: NT, direct drilling of seed genetically modified to tolerate herbicide plus a combination of two pre-emergence and post-emergence herbicides; CT, conventional drilling with an isogenic corn variety plus a pre-emergence herbicide. Management system affected the soil arthropod community, based on major groups. Lower number of arthropods occurred in CT than in NT. Spider and hymenopteran parasitoids, especially those belonging to the families Lycosidae and Diapriidae were the groups that were most clearly affected. The natural field environment seems to favour the presence of Diapriidae. Spiders, in addition to being abundant, behaved in a similar way during both years of each treatment and might therefore be considered as reliable indicator families of the effects of different soil managements on the arthropod population in corn crops. Management system implies alterations on abundance of arthropods populations and natural enemies present in the crop.  相似文献