Influence of conventional and organic agricultural practices on the phenolic content in eggplant pulp: Plant-to-plant variation

Consumer awareness, pesticide and fertiliser contaminations, and environmental concerns have resulted in significant demand for organically grown farm products. The present study evaluates the influence that organic and conventional farming practices exert on the total phenolic content in eggplant samples from two cultivars, Blackbell (American eggplant) and Millionaire (Japanese eggplant), grown by conventional and organic farming practices with similar climatic conditions. In addition, plant-to-plant variation in phenolic content was determined from eight eggplant samples collected from different plants grown at various field positions. Samples were separately assayed for phenolic content by the two independent procedures, HPLC/LC–MS and Folin–Ciocalteu assay. The results of the HPLC analysis showed significant plant-to-plant variation (% RSD ranged from 22% to 48%) in 5-caffeoylqunic acid content (the most abundant phenolic acid) in eight eggplant samples collected from eight different plants belonging to the same cultivar and grown under similar conditions. The cv. Millionaire showed a higher total phenolic content compared to the Blackbell cultivar. We did not observe significant consistent trend in the phenolic content of eggplant samples grown with organic and conventional farming practices with both eggplant cultivars. We, however, observed a strong correlation (R² = 0.87) between total phenolic content as assayed by Folin–Ciocalteu assay and 5-caffeoylqunic acid, a major phenolic acid in eggplant extract. This study concludes that multiple repetitive analyses of plant products collected from different plants grown over various time periods (seasons) at different locations should always be carried to unambiguously prove the impact of growing conditions on phenolic content or antioxidant activity.     

Quality Measurement of Intact and Fresh-cut Slices of Fuji, Granny Smith, Pink Lady, and GoldRush Apples

ABSTRACT: Development of fresh-cut apple products requires consideration of cultivars that store well as both intact and fresh-cut fruit. We compared the instrumental and sensory quality of 2 apple cultivars, Granny Smith and Fuji, that are used for fresh cutting with 2 new cultivars, Pink Lady and GoldRush, which were considered to have quality characteristics suitable for fresh cutting. Firmness, titratable acidity (TA), soluble solids content (SSC), and aromatic volatile concentration were measured in intact fruit of the 4 cultivars during 12 mo storage in air at 0 °C and during 3 wk storage at 5 °C as fresh-cut slices. After 1 wk storage as fresh-cut slices, sensory evaluations for acceptability of flesh and peel appearance, flavor, texture, and overall eating quality were performed. During storage, GoldRush apples maintained > 80 N firmness, approximately 17% SSC, > 0.5% TA, and had high aromatic volatile production, that is, maintained quality better than the other cultivars. The quality and shelf stability of GoldRush slices were also as good as or better than slices from the other cultivars, whereas Granny Smith slices generally rated lower than the other cultivars. The acceptability of flavor, texture, and overall eating quality of GoldRush slices was as good as that for Pink Lady and Fuji. The quality of GoldRush apples can be maintained throughout the year in refrigerated air storage and still remain suitable for fresh-cut processing. The results indicate that GoldRush and Pink Lady are 2 promising new, high-quality apple cultivars for fresh cutting. Keywords: fresh-cut fruit, Malus × domestica , postharvest quality, respiration rate, shelf life     

Determination of milk and blood concentrations of lipopolysaccharide-binding protein in cows with naturally acquired subclinical and clinical mastitis

Blood and milk concentrations of the acute phase protein lipopolysaccharide-binding protein (LBP) were evaluated in cows with naturally occurring mastitis. Blood and milk samples were collected from 101 clinically healthy dairy cows and 17 dairy cows diagnosed with clinical mastitis, and the LBP concentrations of the samples were measured by an ELISA. Concentrations of LBP were greater in the blood and milk of cows with clinical mastitis than in those with healthy quarters. Concentrations of LBP also differed between uninfected and subclinically infected quarters with low somatic cell count. Blood concentrations of LBP in cows with subclinical intramammary infections could not be differentiated from those of cows with all healthy quarters. Together, these data demonstrate that increased blood and milk concentrations of LBP can be detected in dairy cows with naturally acquired intramammary infections that cause clinical mastitis.     

Effects of Geldanamycin on Hatching and Juvenile Motility in <Emphasis Type="Italic">Caenorhabditis elegans</Emphasis> and <Emphasis Type="Italic">Heterodera glycines</Emphasis>

Several Streptomyces species are known to produce metabolites that inhibit plant pathogens. One such compound is geldanamycin (GA), a benzoquinone ansamycin originally isolated from Streptomyces hygroscopicus. We examined the effect of geldanamycin on egg hatch and juvenile motility in Caenorhabditis elegans and in two populations of the plant-parasitic nematode Heterodera glycines. When C. elegans eggs were exposed to geldanamycin, both hatch and motility were reduced by GA doses between 2 and 50 μg/ml. The H. glycines inbred populations TN17 and TN18 exhibited low dose stimulation of hatch and motility, whereas levels occurring at higher GA doses were at or below control levels. These experiments represent the first demonstration of geldanamycin effects in C. elegans and H. glycines and suggest that the heat shock chaperone Hsp90, the known molecular target of geldanamycin, may be involved in nematode egg hatch and motility. This study also indicates that geldanamycin-producing strains of Streptomyces may be useful as biocontrol agents for nematodes.     

Effects of supplemental source of magnesium and inclusion of buffer on ruminal microbial fermentation in continuous culture

Magnesium oxide (MgO) is the most common supplemental source of Mg for dairy cows and a proven ruminal alkalizer when supplemented above NRC (2001) recommendations. However, overfeeding MgO may increase feeding costs, whereas the effects of alternative sources of Mg on ruminal fermentation are not well known. Moreover, it is still unclear if Mg supplementation influences the effects of bicarbonate-based buffers on ruminal fermentation. We aimed to evaluate the effect of Mg source on ruminal fermentation with diets formulated to a final concentration of 0.25% Mg, and to determine if the effect of sodium sesquicarbonate as a buffer varies with the source of Mg. We used 8 fermentors in a duplicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments, by combining 2 factors: (1) Mg source: using either MgO or an alternative source consisting of a blend of CaMg(OH)₄ and CaMg(CO₃)₂ (BLN) and (2) sodium sesquicarbonate buffer inclusion, at 0 or 0.6% of dry matter intake. Based on preliminary tests of reactivity, we hypothesized that BLN plus buffer would allow for greater ruminal pH, acetate molar proportion, and NDF digestibility than diets with MgO or without buffer. Four 10-d periods were completed, where the last 3 d were used for pH measurements and collection of samples for volatile fatty acids (VFA), ammonia (NH₃-N), Mg solubility, N metabolism, and nutrient digestibility. Effects of Mg source (source), sodium sesquicarbonate inclusion (buffer), and their interaction (source × buffer) were tested with the MIXED procedure of SAS (SAS Institute Inc.). We did not find an effect of Mg source on ruminal fermentation variables; however, concentration of soluble Mg in ruminal fluid was greater for MgO compared with BLN. On the other hand, buffer supplementation increased average ruminal pH, acetate molar proportion, and branched-chain VFA molar proportion; tended to increase NDF digestibility; and decreased both area under the curve and time below pH 6.0. An interaction of source × buffer was found for propionate, butyrate, and NH₃-N, the first one decreasing and the 2 others increasing only when buffer was supplemented to the BLN diet. Our results indicate that supplementing Mg with either MgO or BLN promotes similar ruminal fermentation in diets with total concentration of 0.25% Mg. Further evaluations are needed to assess Mg availability and animal performance in dairy cows fed BLN.     

Effects of tomato variety, temperature differential, and post-stem removal time on internalization of Salmonella enterica serovar Thompson in tomatoes

Tomatoes have been implicated in salmonellosis outbreaks due to possible contamination through bacterial internalization during postharvest handling. This study was conducted to determine the effects of tomato variety, temperature differential between tomato pulp and bacterial suspension, and the time delay between stem removal and immersion in bacterial suspension on internalization of Salmonella enterica serovar Thompson in tomato fruit. Mature green tomatoes at 32.2°C were immersed in water containing approximately 10(6) CFU/ml S. enterica bacteria. Different tomato varieties (Mountain Spring, Applause, and BHN961), temperature differentials (-10, 0, and 10°F, or -5.6, 0, and 5.6°C, respectively), and post-stem removal times (0, 2, and 16 h) were evaluated for their effects on S. enterica internalization. The incidence and density of internalized cells were determined by culture enrichment and most-probable-number methods, respectively. Overall, variety and post-stem removal time by variety interaction significantly affected the incidence of S. enterica internalization (P < 0.0001), while temperature differential had no significant effect (P = 0.36). Mountain Spring tomatoes were less susceptible to S. enterica internalization than were Applause and BHN961. Increasing the time interval between stem removal and immersion greatly reduced pathogen internalization in BHN961 and Applause, while it had no effect in Mountain Spring tomatoes. The variety and interactions between varieties and post-stem removal times (P = 0.0363) and between temperature differentials and post-stem removal times (P = 0.0257) had significant effects on the populations of internalized S. enterica. Furthermore, all internalized S. enterica cells were found within the core tissue segments immediately underneath the stem scars.     

Density and viscosity of ammonium nitrate,ammonium nitrate–potassium chloride and ammonium nitrate—ammonium phosphate melts

The results of density and viscosity measurements are given for ammonium nitrate and the salt mixtures ammonium nitrate—potassium chloride and ammonium nitrate-ammonium dihydrogen phosphate. The latter system is complicated because of the formation of non-ortho phosphates and the results obtained refer to the equilibrium mixture obtained after heating for 3 h at 180°c. After this treatment, about 40% of the phosphate was converted to non-ortho forms. The density of ammonium nitrate is given by: for values of t between 170°c and 190°c. Similar relationships can be deduced for the solutions. The viscosity of ammonium nitrate, in centipoises, is given approximately by: for values of T between 443° and 453° k. Similar relationships hold for the nitrate—phosphate solutions.     

A method to estimate soybean seed protein and oil concentration before harvest

Temperature and precipitation variables during linear seed fill are known to be environmental determinants of protein and oil composition of the soybean [Glycine max (L.) Merr.] seed. However, the contribution of other precipitation and temperature events during the growing season and a method that would determine the precipitation and temperature variables most related to protein and oil concentration values of the seed has not been fully explored. The former was evaluated by comparing monthly temperature and precipitation variables of the growing seasons to protein and oil data for the years 1959 to 1996 from three locations listed in the Uniform Soybean Tests, Northern Region. The data set comprised locations from Maturity Groups II and III and consisted of 186 location-years. Classification and regression “tree-based” analysis were conducted to determine the month, environmental variable, and “splitting” points that correctly classified most of the 186 location-years for below-vs.-above-median protein or oil composition. The protein concentrations from the location-years were separated into these two median-boundary categories most readily by temperature variables from the months of April and August. The oil concentrations from the location-years were classified best by August and September temperature variables and precipitation in May and September. The sum of protein and oil concentrations from the location-years were best separated by August and July temperature variables and precipitation in May and July. The protein-to-oil ratios from the location-years were best separated by September precipitation and July and June temperature variables. These data demonstrate that tree-based models can use monthly temperature and precipitation variables during linear seed fill and other specific months of the crop year and relate them to the final protein and oil concentration in the seed. These results could be used by the processing industry to estimate seed composition before harvest.     

Enhanced electrogenerated chemiluminescence in the presence of fluorinated alcohols

The electrochemistry, UV-vis absorption, photoluminescence (PL), and coreactant electrogenerated chemiluminescence (ECL) of Ru(bpy)3(2+) (where bpy=2,2'-bipyridine) have been obtained in a series of hydroxylic solvents. The solvents included fluorinated and nonfluorinated alcohols and alcohol/water mixtures. Tri-n-propylamine was used as the oxidative-reductive ECL coreactant. Blue shifts of up to 30 nm in PL emission wavelength maximums are observed compared to a Ru(bpy)3(2+)/H2O standard due to interactions of the polar excited state (i.e., *Ru(bpy)3(2+)) with the solvent media. For example, Ru(bpy)3(2+) in water has an emission maximum of 599 nm while in the more polar hexafluoropropanol and trifluoroethanol it is 562 and 571 nm, respectively. ECL spectra are similar to PL spectra, indicating the same excited state is formed in both experiments. The difference between the electrochemically reversible oxidation (Ru(bpy)3(2+/3+)) and first reduction (Ru(bpy)2(2+/1+)) correlates well with the energy gap observed in the luminescence experiments. Although the ECL is linear in all solvents with [Ru(bpy)3(2+)] ranging from 100 to 0.1 nm, little correlation between the polarity of the solvent and the ECL efficiency (phiecl=number of photons per redox event) was observed. However, dramatic increases in phiecl ranging from 6- to 270-fold were seen in mixed alcohol/water solutions.