FTIR-ATR analysis of brewed coffee: effect of roasting conditions

FTIR-ATR was used to study the effect of roasting conditions on the flavor of brewed coffee using Guatemala Antigua coffee beans. The 1800-1680 cm(-1) carbonyl region for vinyl esters/lactones, esters, aldehydes, ketones, and acids was found to provide a flavor-print of the brewed coffee. A study of light, medium, and dark roasts indicated that when the rate of heating to the onset of the first and second cracks was kept constant, the types of carbonyl compounds formed were similar, varying only in their concentration. This difference in concentration is apparently due to the additional heating of the coffee bean beyond the second crack. When the heating rate to the onset of the first and second crack was varied, both the types and concentration of the carbonyl compounds formed during roasting were affected. Thus, heating rates of green coffee beans to the onset of the first and second cracks are important determinants of the basic taste and aroma of brewed coffee.     

Analysis of Piperaceae germplasm by HPLC and LCMS: a method for isolating and identifying unsaturated amides from Piper spp extracts

A method for extraction and high performance liquid chromatography-mass spectrometer (HPLC-MS) analysis of the medicinally important genus Piper (Piperaceae) was developed. This allows for a rapid and accurate measure of unsaturated amides, or piperamides, in black pepper, Piper nigrum L., and in wild species from Central America. Reflux extraction provided the highest recovery of piperine (>80%) from leaf and peppercorn material. HPLC analysis using a binary gradient of acetonitrile and water separated the major amide peaks between 5 and 12 min. Atmospheric pressure chemical ionization (APCI)-MS improved the detection limit to 0.2 ng, 10-fold below the 2 ng limit of the HPLC-diode array detector (DAD) based on linear standard curves between 0.1 and 250 microg/mL (R2 = 0.999). The HPLC-MS method identified pellitorine, piperylin, 4,5-dihydropiperlonguminine, piperlonguminine, 4,5-dihydropiperine, piperine, and pipercide. The biological activity of six Costa Rican Piper species assessed by mosquito larval bioassays correlated well with piperamide content.     

Bioautography and chemical characterization of antimicrobial compound(s) in commercial water-soluble annatto extracts

Annatto preparations based on extracts of the seed of tropical bush Bixa orellana L consist of carotenoid-type pigments. Previous reports indicate that commercial annatto extracts have biological activities against microorganisms of significance to food fermentation, preservation, and safety. The objective of this study was to separate and identify the compound(s) responsible for the antimicrobial activity of annatto preparations. Commercial water-soluble annatto extracts were screened by thin-layer chromatography and bioautography followed by liquid chromatography/photodiode array/mass spectrometry (LC/PDA/MS) analysis of active fractions. Bioautography revealed two fractions with antimicrobial activity against Staphylococcus aureus. LC/PDA/MS analysis of both fractions revealed 9'-cis-norbixin (UV(max) 460 and 489 nm) and all-trans-norbixin (UV(max) 287, 470, and 494 nm) as the major components. Structure confirmation was achieved by (1)H NMR spectroscopy. Results indicate that 9'-cis-norbixin and all-trans-norbixin are responsible for the antimicrobial properties of annatto.     

Effects of filter type and extraction efficiency on nitrogen mineralization measurements using the aerobic leaching soil incubation method

Aerobic incubation of soils with sequential leachings to extract mineralized N is often used to determine N mineralization potential and N availability in the laboratory. This study used tropical forest soils with differing mineralogy and texture to address: (1) the effects of filter type and equilibration time on soil moisture and N mineralization and (2) the N extraction efficiency of 0.01 M CaCl₂, minus-N nutrient solution (containing 0.004 M CaCl₂) and 2 M KCl. Use of glass microfiber filters compared to cellulose acetate or polyethersulfone membrane filters resulted in a lower moisture content for both low-and high-clay soils. However, filter type did not affect N mineralization. Under 47 kPa suction, soil moisture equilibration occurred between 240 and 360 min regardless of filter type. Extraction efficiency for mineralized N using 0.01 M CaCl₂ or minus-N nutrient solution was lower in forest soils of smectitic mineralogy and soils with a higher proportion of macroaggregates. However, with the exception of allophanic soils, the cumulative amount of N mineralized measured in a long-term incubation for approximately 1 year was not different when either a leaching or an unleached incubation method was used. These results indicate that researchers may wish to conduct preliminary evaluations to determine whether their incubation method will achieve a desired uniform moisture level and N extraction efficiency.     

Analysis of dietary supplements for arsenic,cadmium, mercury,and lead using inductively coupled plasma mass spectrometry

The arsenic, cadmium, mercury, and lead contents of 95 dietary supplement products were determined using microwave digestion and high-resolution inductively coupled plasma mass spectrometry. Precision and accuracy were demonstrated by element recovery from 17 dietary supplements and replicates of 8 reference materials. The concentration ranges were as follows: arsenic, <5-3770 microg/kg; cadmium, <10-368 microg/kg; mercury, <80-16800 microg/kg; and lead, <20-48600 microg/kg. An assessment of estimated exposures/intakes of the four elements is presented.     

Biodiversity of micro-eukaryotes in Antarctic Dry Valley soils with <5% soil moisture

Soils in the Dry Valleys of Antarctica are considered to be among the world's most extreme environments. These soils are old, cold and dry with low contents of organic carbon and nitrogen. Habitats adjacent to water (lakes and ice melts) have significant biological activity as demonstrated by the presence of algal mats, lichens and small invertebrates, particularly nematodes, tardigrades and rotifers. In contrast, there are extensive areas in the Dry Valleys that are extremely dry with less than 5% moisture content. These soils are often salty and appear to be barren of life as they have a coarse texture due to their lack of plant organic material. In contrast, molecular techniques (DNA extraction from soils, cloning and rDNA sequence analysis) demonstrated the presence of a complex micro-eukaryotic food web whose structure and composition varied with moisture content and location. Micro-eukaryotic communities in soils with 0.2-1.3% moisture were represented by species of the yeast genus Trichosporon and an unidentified clade of micro-eukaryotes, whereas levels from 3.1% to 4.9% contained complex food webs including primary producers (chlorophytes and stramenopiles), symbionts (lichen associated fungi), saprophytes (fungi), predators (alveolates and cercozoans) and fungal nematode parasite/pathogens. The soils had a diversity of species (80 species from 15 sites) with a restricted number (3-21 species) at each site. The sensitive and measurable community structure of the low moisture Dry Valley soils provides an unparalleled opportunity to examine local and global environmental effects on micro-eukaryotic community dynamics with multiple trophic levels.     

The recent decline of a New Zealand endemic: how and why did populations of Archey's frog Leiopelma archeyi crash over 1996-2001?

Dramatic changes have been documented in New Zealand's vertebrate faunas since human settlement, involving major declines and extinctions, but over recent years few species have declined in numbers so rapidly as the terrestrial Archey's frog Leiopelma archeyi (Anura: Leiopelmatidae). Long-term monitoring over more than 20 years revealed a major population reduction of the species over 1996-2001 and L. archeyi is now classified as Nationally Critical under the New Zealand threat classification system. The decline progressed northwards in the Coromandel ranges, and mostly larger (female) frogs survived. On a 100 m² study plot at Tapu Ridge, annual population estimates averaged 433 frogs (SE ±32) over 1984-1994, declining by 88% to average 53 frogs (SE ±8) over 1996-2002. A mean annual survival rate of 82% for most years declined to 33% over 1994-1997. There is mounting evidence to suggest that disease is the major agent of decline, supported by (1) the rapidity and severity of decline, (2) the progressive (south to north) nature of decline, and (3) finding frogs with chytriodiomycosis from Batrachochytrium dendrobatidis at the time of decline. Surprisingly, sympatric populations of the semi-aquatic Leiopelma hochstetteri have not declined dramatically, nor has a western population of L. archeyi at Whareorino, despite chytridiomycosis occurring in some frogs there. Sustaining and restoring populations of L. archeyi in New Zealand raises major challenges for conservation management.     

Estimating evaporation: A comparison between Penman, Idso-Jackson, and zero-flux methods

A field evaporation—drainage study was conducted to compare three methods of predicting evaporative losses from a bare soil. Two of the methods (modified Penman combination and Idso—Jackson) are dependent only on measurements of atmospheric parameters whereas the third method (plane of zero flux) is dependent only on measurements of soil parameters.A Captina soil profile was wet up and allowed to dry by evaporation and drainage. For the initial two days after infiltration ceased all three methods predicted similar evaporative losses. Differences between the three methods occurred when the soil moisture content at the soil surface controlled the evaporation rates. Under the three drying conditions the three methods behaved somewhat differently in the prediction of the amounts of water evaporated from the soil surface. Lower losses by evaporation were predicted by the Idso—Jackson and zero-flux methods. In the case of the Idso—Jackson method this result was attributed to the influence of clouds on albedo, the impact of wind and the importance of albedo in the predictive equation. For the zero-flux method the decrease in evaporation was due to lower soil water contents and matrix potentials near the surface which resulted in lower transport rates of water to the surface.     

Tomato Spotted Wilt Virus (TSWV) resistance in tomato derived from Lycopersicon chilense Dun. LA 1938

Tomato spotted wilt virus (TSWV) resistance wasidentified in Y118 (Fla 925-2), an F₁BC₁S₆ tomato line(Lycopersicon esculentum Mill.), derived from a crosswith L. chilense Dun. (LA 1938). This line waspreviously selected for tomato mottle virus (ToMoV)resistance in Florida. Progeny from crosses betweenFla 925-2 and three different TSWV susceptible L.esculentum parents were used in TSWV resistancestudies. A total of 75 F₁ and 596 F₂ plants from allthree crosses were screened for TSWV resistance. ForF₂ plants free of TSWV symptoms, evaluations were madeusing enzyme-linked immunosorbent assay (ELISA). TenF₃ populations used for further greenhouse and fieldscreenings were selected from F₂ plants found to befree of the virus using visual and ELISA criteria ateach evaluation. One F₁ and four F₃ lines werestudied under field conditions (Stellenbosch, SouthAfrica) in which 100% of the `Flora-Dade' susceptiblecontrols were severely infected with TSWV. Theresults of the field study clearly establish that TSWVfield resistance is present in the Fla 925-2 (Y118)derived lines. Studies conducted on these linesrevealed that this resistance has the distinctcharacteristic of often `recovering' from initiallyhigh levels of virus titer in the tissue to levelsbelow detection with ELISA.