Dietary fibre of coconuts from a pacific atoll: Soluble and insoluble components in relation to maturity

Polysaccharide fractions were measured in coconuts at three stages of maturity, which corresponded to dietary usage in the Tokelau Islands of the South Pacific. Kernel was sequentially extracted with cold water (CW), hot water (HW) hot 0.5% ammonium oxalate (HOX), 1M H² SO⁴ and 72% H² SO⁴, and the monosaccharide compositions of the fractions determined. Total readily soluble fractions (CW+HW+HOX) were predominantly galactomannan, and decreased from 77% of the polysaccharide in the immature kernel to 8.8% of that in the mature kernel. Insoluble mannan increased during maturation to be the major polysaccharide component in mature kernel. This indicates that marked differences exist between the three stages of maturity examined, in the properties of their dietary fibre. The results suggest that in studies of diets in which coconut is a staple part, there is a need for careful definition of the coconut component with respect to maturity. Furthermore, they show the importance of using dietary fibre methods which are appropriate to the solubility characteristics of the indigestible polysaccharide.     

The Stability of Theaflavins During HPLC Analysis of a Decaffeinated Aqueous Tea Extract

It has been shown that the theaflavins and thearubigin hump of decaffeinated aqueous extracts of black tea remain virtually stable for up to 850 min, thus permitting their automated overnight analysis. Within-run coefficients of variation for the total chromatogram area and peak area for each of the major theaflavins, following repeated (up to 10 times) injections of a single extract, did not exceed 2·5 and 6·0%, respectively. The corresponding values obtained by pooling data obtained on three separate occasions were 3·0 and 7·3%, respectively. Trend-line analysis indicated that there was a tendency for each of the areas studied to decline by factors in the range 0·11–0·53% of the original value per injection. This factor was not statistically significant for theaflavin-3,3′-digallate but reached 5% significance for theaflavin and total chromatogram area and 1% for both theaflavin monogallates. The magnitude of these changes is too small to warrant an avoidance of automated sample handling in routine screening or quality assurance programmes where the increased throughput allowed is advantageous. It was also noted that the use of citric acid to acidify the chromatographic solvents was not superior to acetic acid. © 1997 SCI.     

Influence of drying mode on iridoid bitter constituent levels in gentian root

Root samples of wild gentian (Gentiana lutea L) were harvested from six localities (altitude 970 m to 1350 m) from May to November 2000. Each batch of roots was split into three: fresh roots, naturally dried roots (ambient air) and artificially dried roots (40 °C). In all the samples, levels of iridoid bitter constituents and of xanthone coloured compounds were determined by HPLC. The mean total iridoid content in the fresh roots was 102.4 g kg^?1 in dry matter (DM). The mean level of the principal bitter compound gentiopicroside was particularly high at 81 g kg^?1 DM. Loganic acid, not previously reported in G lutea, was the second most abundant bitter compound at a mean level of 14.3 g kg^?1 DM. Swertiamarin was present at 5.4 g kg^?1, with another minor unidentified iridoid. Levels of iridoid compounds were strongly dependent of the drying mode. These amounts were 88.5 g kg^?1 DM in artificially dried roots and 62.5 g kg^?1 DM in naturally dried roots, mostly owing to a marked decrease in gentiopicroside. The temperature of 40 °C preserved the bitter compounds and the bitterness of fresh gentian roots. The amount of coloured xanthones was relatively low at 3.3 g kg^?1 and did not change with the drying mode. Copyright © 2004 Society of Chemical Industry     

Use of volatile compound metabolic signatures in poultry liver to back-trace dietary exposure to rapidly metabolized xenobiotics

The study investigated the feasibility of using volatile compound signatures of liver tissues in poultry to detect previous dietary exposure to different types of xenobiotic. Six groups of broiler chickens were fed a similar diet either noncontaminated or contaminated with polychlorinated dibenzo-p-dioxins/-furans (PCDD/Fs; 3.14 pg WHO-TEQ/g feed, 12% moisture), polychlorinated biphenyls (PCBs; 0.08 pg WHO-TEQ/g feed, 12% moisture), polybrominated diphenyl ethers (PBDEs; 1.63 ng/g feed, 12% moisture), polycyclic aromatic hydrocarbons (PAHs; 0.72 μg/g fresh matter), or coccidiostats (0.5 mg/g feed, fresh matter). Each chicken liver was analyzed by solid-phase microextraction - mass spectrometry (SPME-MS) for volatile compound metabolic signature and by gas chromatography - high resolution mass spectrometry (GC-HRMS), gas chromatography - tandem mass spectrometry (GC-MS/MS), and liquid chromatography - tandem mass spectrometry (LC-MS/MS) to quantify xenobiotic residues. Volatile compound signature evidenced a liver metabolic response to PAH although these rapidly metabolized xenobiotics are undetectable in this organ by the reference methods. Similarly, the volatile compound metabolic signature enabled to differentiate the noncontaminated chickens from those contaminated with PBDEs or coccidiostats. In contrast, no clear signature was pointed out for slowly metabolized compounds such as PCDD/Fs and PCBs although their residues were found in liver at 50.93 (±6.71) and 0.67 (±0.1) pg WHO-TEQ/g fat, respectively.     

Combining land use information and small stream sampling with PCR-based methods for better characterization of diffuse sources of human fecal pollution

Diffuse sources of human fecal pollution allow for the direct discharge of waste into receiving waters with minimal or no treatment. Traditional culture-based methods are commonly used to characterize fecal pollution in ambient waters, however these methods do not discern between human and other animal sources of fecal pollution making it difficult to identify diffuse pollution sources. Human-associated quantitative real-time PCR (qPCR) methods in combination with low-order headwatershed sampling, precipitation information, and high-resolution geographic information system land use data can be useful for identifying diffuse source of human fecal pollution in receiving waters. To test this assertion, this study monitored nine headwatersheds over a two-year period potentially impacted by faulty septic systems and leaky sanitary sewer lines. Human fecal pollution was measured using three different human-associated qPCR methods and a positive significant correlation was seen between abundance of human-associated genetic markers and septic systems following wet weather events. In contrast, a negative correlation was observed with sanitary sewer line densities suggesting septic systems are the predominant diffuse source of human fecal pollution in the study area. These results demonstrate the advantages of combining water sampling, climate information, land-use computer-based modeling, and molecular biology disciplines to better characterize diffuse sources of human fecal pollution in environmental waters.     

Mid-infrared spectroscopy as a tool for rapid determination of internal quality parameters in tomato

The objective of this study was to investigate the possibility of predicting the quality parameters of tomato by mid-infrared spectroscopy. For 2 years, tomato samples, representing a large variability in the chemical composition, were scanned using the attenuated total reflectance accessory of a Fourier transform spectrometer in the wavenumber region between 4000 and 400 cm⁻¹_. Calibration models were developed using partial least squares (PLS) regression method and were tested with internal validation sample set in the first year. Different spectral preprocessing techniques were investigated and different spectral regions were selected to optimise the calibration models. In addition, the models obtained in 2007 were used to predict the soluble solids, dry matter and total acidity in tomato harvested in 2008.     

Comprehensive survey of pasteurized fluid milk produced in the United States reveals a low prevalence of Listeria monocytogenes

A comprehensive survey was undertaken to generate contemporary data on the prevalence of Listeria monocytogenes in pasteurized fluid milk produced in the United States. Samples (5,519) near the sell-by expiration date were purchased at retail outlets over a 5-week period and analyzed for presence of L. monocytogenes. Products consisted of whole milk, nonfat milk, and chocolate milk packaged in gallon, half gallon, quart, pint, and half-pint containers. Samples were collected from both large and small retail stores in urban and suburban locations in four FoodNet cities (Baltimore, Md., Atlanta, Ga., St. Paul/ Minneapolis, Minn., and San Francisco, Calif.). Samples were prescreened for L. monocytogenes by the AOAC-approved rapid Vitek immunodiagnostic assay system, enzyme-linked fluorescent assay method. Positive prescreening samples were cultured according to the Bacteriological Analytical Manual, enumerated for L. monocytogenes with a nine-tube most-probable-number (MPN) procedure, and confirmed by biochemical characterization. The frequency of isolation of L. monocytogenes in these products was 0% (0 of 1,897) in whole milk, 0.05% (1 of 1,846) in nonfat milk, 0% (0 of 1,669) in chocolate milk, and 0% (0 of 107) in other (reduced fat and low fat) milk samples. Overall, L. monocytogenes was confirmed in only 0.018% of pasteurized milk samples (1 of 5,519). Enumeration of the single confirmed positive nonfat milk sample revealed low-level contamination (<0.3 MPN/g), even when sampled 5 days past the expiration of the sell-by date. The results confirm the low frequency of contamination of pasteurized fluid milk products by L. monocytogenes for products sold in the United States and reaffirm the reduction of contamination frequency of fluid milk by L. monocytogenes when compared with earlier estimates from the U.S. Food and Drug Administration Dairy Safety Initiatives Program.     

A comparative study on the antioxidative and anti‐allergic activities of fresh and aged black garlic extracts

The antioxidative and anti‐allergic activities of fresh and aged black garlic extracts were investigated. The garlic samples were extracted with 70% ethanol (v/v) and the total phenolic content was measured. The antioxidant capacity of extracts was assessed by determining the scavenging activities on 1,1‐diphenyl‐2‐picrylhydrazyl and hydroxyl radicals, ferricyanide reducing power, ferrous ion‐chelating ability and inhibitory effect on linoleic acid peroxidation. The anti‐allergic activity of extracts was analysed by measuring their inhibitory effects against β‐hexosaminidase release. The aged black garlic exhibited significantly higher phenolic content and greater antioxidative activity than fresh garlic. Both garlic extracts showed strong antioxidant capacity in a dose‐dependent manner. On the other hand, a considerably higher suppression of β‐hexosaminidase release was found in fresh garlic extract at lower concentration compared with that of the black garlic. Results of this study illustrate that ageing of garlic could enhance its antioxidant capacity, but could decrease its anti‐allergic activity.     

Interlaboratory comparison of real-time PCR protocols for quantification of general fecal indicator bacteria

The application of quantitative real-time PCR (qPCR) technologies for the rapid identification of fecal bacteria in environmental waters is being considered for use as a national water quality metric in the United States. The transition from research tool to a standardized protocol requires information on the reproducibility and sources of variation associated with qPCR methodology across laboratories. This study examines interlaboratory variability in the measurement of enterococci and Bacteroidales concentrations from standardized, spiked, and environmental sources of DNA using the Entero1a and GenBac3 qPCR methods, respectively. Comparisons are based on data generated from eight different research facilities. Special attention was placed on the influence of the DNA isolation step and effect of simplex and multiplex amplification approaches on interlaboratory variability. Results suggest that a crude lysate is sufficient for DNA isolation unless environmental samples contain substances that can inhibit qPCR amplification. No appreciable difference was observed between simplex and multiplex amplification approaches. Overall, interlaboratory variability levels remained low (<10% coefficient of variation) regardless of qPCR protocol.     

Aloysia triphylla infusion protects rats against dextran sulfate sodium-induced colonic damage

BACKGROUND: Inflammatory bowel diseases consist of uncontrolled intestinal inflammation leading to mucosal disruption. Polyphenols are micronutrients with antioxidant and anti‐inflammatory properties and may play an interesting role in the prevention of intestinal inflammation. Lemon verbena (Aloysia triphylla (L'Herit.) Britton, Verbenaceae) infusion is a popular herbal drink rich in polyphenols. This study evaluated the protective effects of lemon verbena infusion consumption on the development of dextran sulfate sodium (DSS)‐induced colitis in rats. The infusion was given to rats as a drink providing 82 µmol polyphenols day^?1 for 21 days. Colitis was induced with 40 g l^?1 DSS in the drink for the last 7 days. RESULTS: Lemon verbena infusion treatment restored body weight gain and prevented colonic shortening. Despite no protective effect on myeloperoxidase activity, A. triphylla infusion limited histological colonic alterations. CONCLUSION: The results suggest that lemon verbena infusion partially protects rats against DSS‐induced inflammation. Copyright © 2011 Society of Chemical Industry