Effect of variety and maturation of cheese on supercritical fluid extraction efficiency

Supercritical fluid extraction (SFE) has been utilized by the food industry in many applications to extract, fractionate, and recover compounds from various food matrices. However, little research has been conducted using SFE as an alternative process for producing reduced-fat cheese. Lipids in cheeses may be selectively extracted due to the nonpolar properties of supercritical carbon dioxide (SC-CO2), without leaving residual chemicals as is the case in solvent extraction. The objective of this study was to evaluate the influence on the extraction process due to cheese variety and protein breakdown by age. A Latin square design was utilized to test the extractability of lipids from Parmesan and Cheddar cheeses, aged young (9-10 months) or old (24 months). Extraction took place in a 500 mL SFE vessel using 100 g of grated cheese samples. The SFE parameters of the extraction were 350 bar, 35 degrees C, and supercritical carbon dioxide at a flow rate of 20 g/min for 55 min. Compositional analysis measured all treated samples and controls of total lipids, lipid profiling, total protein, protein/peptide analysis, moisture, ash, and pH. Cheese type was a major variable in fat extraction. The extraction in Cheddar showed an average fat reduction of 53.56% for young cheese, whereas that in old Cheddar was 47.90%. However, young Parmesan was reduced an average of 55.07%, but old Parmesan was reduced at 68.11%, measured on a dry basis. SFE extracted triglycerides and cholesterol, but did not remove phospholipids. This investigation introduces the observations of the effect of Cheddar and Parmesan varieties on SFE, offering data on the important parameters to consider in the design of SFE processes to reduce fat in cheese.     

Assessment of fungal communities in soil and tomato roots subjected to diverse land and crop management systems

Effects of diverse agricultural land management practices on soil and on root colonizing fungal communities were determined through a PCR-based molecular method and a culture-dependent method, respectively, in a field location with uniform soil type. Initiated in July 2000, the management systems were: conventional tomato production, frequent tillage (disk fallow), undisturbed weed fallow, bahiagrass pasture (Paspalum notatum var. notatum ‘Argentine’), and an organically managed system including cover crops and annual applications of poultry manure and urban plant debris. Culture-dependent colony counting was used to identify and enumerate communities of root colonizing fungi and length heterogeneity polymerase chain reaction (LH-PCR) analysis of internal transcribed spacer-1 (ITS-1) profiles to characterize phylotypes in soil fungal communities. Three years after initiation of land management treatments and midway through tomato cultivation, both methods detected a high degree of similarity in fungal community composition between weed fallow and bahiagrass plots. Soil fungal communities in organically managed plots were similar to each other and distinct from communities in other land management systems while the composition of root colonizing fungal communities in organic plots was divergent. The results demonstrate that the soil fungal communities and root colonizing fungal communities were affected differently depending on land and crop management practices. Fusarium oxysporum was a dominant species in all soil and root colonizing fungal communities except those subjected to organic management practices.     

Mapping within-field variability in wheat yield and biomass using remote sensing vegetation indices

Precision Agriculture - This paper explored the ability of remote sensing (RS) and meteorological data to map the variability of yield/biomass in cultivated wheat (Triticum aestivum). The...     

A dynamic grain flow model for a mass flow yield sensor on a combine

A model is developed to describe the flow of grain through a clean grain elevator system on a combine in order to facilitate accurate mass flow rate estimation. The relationship between mass flow rate and impact force described by the model depends upon machine operational characteristics, mechanical interactions of the grain and the machine geometry, and material properties of the grain. The model was designed to be adaptable to varying grain conditions, such as those influenced by moisture content, by allowing free parameters of the model to be estimated through a nonlinear regression algorithm. Simulations were performed using discrete element modeling software and data was obtained from experiments conducted on a clean grain elevator system at the University of Kentucky Combine Yield Monitor Test Facility to determine the ability of the model to accurately estimate mass flow rate. The model estimated mass flow rate with a normalized root mean squared residual (NRMSR) less than 2% for discrete element modeling simulations. For experiments involving machine components, NRMSR values were less than 3% for corn at 14% moisture, less than 3% for corn at 21% moisture, and less than 5% for corn at 26% moisture.     

Effect of high-power monochromatic (pulsed UV laser) and low-power broadband UV radiation on Phytophthora spp. in irrigation water

Cysts or zoospores of Phytophthora capsici, P. citrophthora and P. nicotianae were suspended in distilled water or in recycled irrigation water collected from commercial nurseries. Propagules, suspended in shallow layers of still water in 60 mm-diameter plastic Petri dishes with lids off, were exposed to various UV doses emitted from either an excimer laser or a mercury vapor lamp. The laser emitted a monochromatic (248 nm, 5 eV/pulse), pulsed UV beam with an intensity of 1 to 2 mJ/cm²/pulse with 20-ns pulse durations and a high peak power of 50 to 100 kW/cm²/pulse. The UV lamp was from a commercial water purifier that emitted broadband (continuous) UV radiation at an intensity of ～8 mW/cm². Survival was assessed by culturing aliquots of the treated or non-treated suspensions onto corn meal agar amended with ampicillin (250 ppm) and rifampin (10 ppm), and then counting numbers of developing colonies. The UV dose (as energy per unit area) required to kill propagules was smaller when they were suspended in distilled water than when suspended in recycled nursery water. The reduced kill effectiveness in recycled water appears to be related to UV-absorbing soluble chemicals. Cysts and zoospores were equally susceptible to UV, although the high-peak power pulsed-UV laser source with ultra-short exposure times appeared to have greater kill effectiveness than the conventional Hg-vapor UV lamp. Phytophthora capsici and P. nicotianae isolates were somewhat less sensitive to UV than isolates of P. citrophthora obtained from various hosts and geographical regions. Furthermore, hyphae of Phytophthora spp. were less susceptible to UV than were cysts or zoospores.     

Genetic structure and phylogeography of <Emphasis Type="Italic">Juniperus phoenicea</Emphasis> complex throughout Mediterranean and Macaronesian regions: different stories in one

Key message

The genetic structure of Juniperus phoenicea in the Mediterranean Basin is inferred using amplified fragment length polymorphism markers (AFLP) markers. As other Mediterranean conifers, J. phoenicea populations show moderate levels of genetic diversity and interpopulational differentiation. The pattern of distribution of genetic diversity seems highly influenced by the climatic fluctuations which occurred in the Pleistocene.

Context

It has been stated that the genetic structure of Mediterranean conifers is mediated by the historical climatic changes and the geological rearrangements which occurred in the Mediterranean Basin. J. phoenicea provides an excellent example to test how its genetic structure is influenced by these events.

Aims

In this work, we study the amount and distribution of genetic diversity of J. phoenicea complex, in order to evaluate its taxonomic status and to reveal underlying phylogeographic patterns.

Methods

The molecular diversity was analyzed for 805 individuals from 46 populations throughout its distribution range using AFLP markers. Principal coordinate analysis, analysis of molecular variance (AMOVA), and Bayesian-based analysis were applied to examine the population structure.

Results

AFLP markers revealed moderate levels of intrapopulation genetic diversity, pairwise genetic differentiation, and a clear pattern of isolation by distance. Bayesian analysis of population structure showed five clusters related to the taxonomic status of J. phoenicea and J. turbinata, and a geographic pattern of genetic structure in J. turbinata.

Conclusion

All the analysis separate J. phoenicea from J. turbinata. For J. turbinata, up to four groups can be distinguished from a phylogeographic point of view. The genetic structure of J. turbinata seems highly influenced by climatic and geologic fluctuations occurring since the Oligocene.

     

Chemical Behavior of U(VI) in the Presence of Soil Components

Soil components from different environments (forest (OF), semiarid (SZ), and sand (AS)) were separated from fulvic and humic substances, characterized by DRX, EDS(SEM), and zero-charge points were determined. The sorption of U(VI) by these materials was determined considering contact time, concentration of U(VI), pH, ionic strength, and presence of sodium chloride and humic acids. The time to reach the kinetic sorption equilibrium was ca. 1 min for the components of the SZ and AS soils, whereas those from OF required longer times. The zero-charge points of the materials indicate that in the experimental conditions, the surfaces of the materials are positively charged, as are uranyl ions. The sorption kinetic data were well fitted to the pseudo-second-order model, which indicates chemical sorption. The maximum sorption capacities for U(VI) obtained from data fitted to the Langmuir model of OF and SZ were 49 and 19.8 mg g^?1 respectively. Sorption isotherm data for AS were best fitted to the Freundlich model (q_e?=?5.4 mg g^?1). The maximum values of distribution coefficients (K_d) were 23?±?7 L kg^?1, 545?±?64 L kg^?1, and 1178?±?229 L kg^?1 for AS, SZ, and OF, respectively; these values may depend on pH, contact time, initial concentration of U(VI), and the composition of the materials. Sodium chloride in the aqueous solutions affects U(VI) sorption by the materials SZ and AS. The effect of humic acids depends on pH, only in acid media soluble humate complexes may be formed.     

Assessing genetic diversity of wild southeastern North American <Emphasis Type="Italic">Vaccinium</Emphasis> species using microsatellite markers

Wild species representatives from Northwestern, Central and Southern Florida, and neighboring U.S. states were collected in multiple United States Department of Agriculture (USDA) exploration expeditions and are being preserved at the USDA, Agricultural Research Service, National Clonal Germplasm Repository in Corvallis, Oregon. Germplasm from these southeastern regions of North America is particularly vulnerable to loss in the wild due to encroachment of human development in key habitats and biotic and abiotic stresses from climate change. Fourteen simple sequence repeats (SSRs), previously developed from the highbush blueberry (Vaccinium corymbosum) cultivar ‘Bluecrop’, were used to estimate genetic diversity and genetic differentiation of 67 diploid individuals from three species, including 19 V. elliottii, 12 V. fuscatum, and 35 V. darrowii accessions collected throughout the species’ ranges. Results from our analyses indicated that the samples from each species could be reliably resolved using genetic distance measures with ordination and neighbor joining approaches. In addition, we estimated admixture among these species by using Bayesian assignment tests, and were able to identify a mis-labeled accession of V. darrowii ‘Johnblue’, two mis-classified accessions (CVAC 735.001 and CVAC 1223.001), and four accessions of previously undescribed hybrid origin (CVAC 734.001, CVAC 1721.001, CVAC 1741.001, and Florida 4B CVAC 1790). Allele composition at the 14 SSRs confirmed that Florida 4B CVAC 1790, the donor of low chilling for the southern highbush blueberry, was the critical parent of US 74. Genetic diversity assessment and identification of these wild accessions are crucial for optimal germplasm management and expand opportunities to utilize natural variation in breeding programs.     

Metropolitan farmers markets in Minneapolis and Vienna: a values-based comparison

Farmers markets (FMs) have traditionally served as a space for farmers to sell directly to consumers. Recently, many FMs in the US and other regions have experienced a renaissance. This article compares the different value sets embedded in the rules and norms of two metropolitan FM regions—Minneapolis, Minnesota and in Vienna, Austria. It uses a values-based framework that reflects the relationships among FM operating structures (OS) and their values reflected by the key FM participants—i.e., farmer/vendors, consumers and market managers. The framework allows us to focus on two very contrasting value sets of metropolitan FM regions in (1) presenting and discussing the values found and embedded in the two metropolitan market regions; (2) illustrating how the values found are embodied as rules and norms in each FM region; (3) considering the alignment or not of FM participant values with their corresponding FM values; and (4) the differences and commonalities as well as the benefits and challenges of the two market regions. In contrasting metropolitan FMs we explain that FM value sets are complex and differ among and within FM participant groups and are dependent on their respective OS. We show that contrasting two metropolitan FM regions can be useful in understanding beneficial and disadvantageous relationships between the values and structures of, and in FMs, and specifically in examining institutional impediments such as governance. Thus we illustrate the possibilities and limitations of values for and within metropolitan FMs.