Name: composition and properties of aquafaba: water recovered from commercially canned chickpeas
Uploaded: 2018-02-10T14:00:00
Description: Watch this Scientific Journal Video about Composition and Properties of Aquafaba: Water Recovered from Commercially Canned Chickpeas at JoVE.com

This research was supported by the Institute of International Education&#39;s Scholar Rescue Fund (IIE-SRF).

Separation of Aquafaba from Chickpeas
<ol>
	<li>Obtain cans of chick peas from local grocers and open with a manual can opener.</li>
	<li>Label cans from A to J.</li>
	<li>Separate chickpeas from aquafaba using a stainless steel meshed kitchen strainer and weigh the separated chickpeas and aquafaba.</li>
</ol>
Obtain a Representative Sample of Chickpeas and Aquafaba for Chemical Analysis.
<ol start="4">
	<li>Randomly select ten chickpeas after draining the aquafaba to determine moisture conten...

<ol>
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In this research, we have found that chickpea aquafaba from different commercial sources produces foams that vary in both properties (volume and stability of foam) and chemical composition. There was a positive correlation between aquafaba viscosity and moisture content. Foam volume increase (Vf100) was not related to these parameters. Additives such as salt and disodium EDTA might suppress viscosity and foam stability as aquafaba from chickpea canned with these additives had lower viscosity and produced foams...

Increasingly vegetarian products are being developed that mimic the properties of meat, milk, and eggs. The functional properties of pulses are important in their current uses in food applications and their properties are being explored in the development of replacements for animal protein. For example, dairy alternatives sales were $8.80 Billion USD in 2015 and this market is growing rapidly. This market is projected to grow to $35.06 billion by 2024. Moreover, the upward trend in demand for plant-based milk substitutes is, in part, a result of consumer health concerns regarding cholesterol, antibiotics, and growth hormones often used in milk production1. Similarly, vegetable protein and hydrocolloid egg replacer markets are rapidly expanding and a compound annual growth rate of 5.8% is expected for these materials over the next 8 years with sales of $1.5 billion USD expected in 20262. A growing number of consumers prefer vegan protein sources, allergen reduced diets and reduced carbon footprint for food products. Demand for pulse-based products, especially from lentil, chickpea, and faba bean are steadily growing due to the high protein content, dietary fiber and low saturated fat content of pulses3. Pulses also contain phytochemicals with potentially beneficial biological activity4.
Commercial entities, scientists and private individuals have taken different approaches to communicate the quality properties of chickpea based egg and milk replacements. Gugger et al.5 produced a milk-like product from high starch grains including adzuki bean and chickpea. In their described methods the proponents attempted to show that their product is unique and different from &#34;aquafaba&#34;6. In another commercial approach elucidated by Tetrick et al.7 a plant-based egg substitute was developed. Their patent application describes methods of combining pulse flour with known thickeners that emulate the function of egg white in baked materials. Typical formulae include 80-90% pulse flour and 10-20% thickening additives.
Peer reviewed literature also indicates the functionality possible with chickpea and has demonstrated that albumin protein fractions obtained from kabuli and desi chickpea flour have good emulsification properties. They have also found a significant effect of chickpea source on the albumin yield and performance8.
After the initial internet report describing &#34;aquafaba&#34; by French chef Jo&#235;l Roessel, an open source movement is showing the utility of aquafaba as a replacement of egg white and dairy protein in many food applications. There are many highly viewed webpages and YouTube videos showing the incorporation of aquafaba in foods that emulate the qualities of ice cream, meringue, cheese, mayonnaise, scrambled eggs, and whipped cream. Most pioneers providing open source aquafaba applications (recipes) obtain their material by straining canned chickpeas and using the liquid in their recipes. These individuals are mostly not trained scientists. Video comments sections indicate that the respondents have copied the recipes and some have failed to replicate the successes of the aquafaba advocates.
All three approaches (corporate, scientific and open source) to developing egg and milk replacements have merit but are missing an important dimension. Applied scientists, basic scientists and individuals promulgating pulse-based products have incompletely characterized and standardized their input material. Standardization of a product for a specific use is a normal industrial practice. Chickpea cultivars have not been standardized for aquafaba quality and industrial canning practices are standardized to produce consistent chickpeas not aquafaba.
Based on studies of other commodities, it is predictable that both genotype and environment will contribute to pulse aquafaba quality. It is known that both genotype and environment affect kabuli chickpea canning properties9. Typically, genotypic effects are large between related species and smaller within members of a species. Variation in physical and chemical properties can be minimized through identity preservation that allows the selection of cultivars with desired properties. Environmental effects can also be large and are managed by quality evaluation and blending to standard performance in specific tests10.
There are many genetically distinct cultivars of chickpea in commercial production. For examples, the University of Saskatchewan Crop Development Centre, a major source of commercial chickpea germplasm, has released 23 chickpea cultivars since 1980 of which 6 are currently recommended for cultivation in Canada. While scientific manuscripts often describe the cultivar used in a study, the patents and internet pages that were surveyed did not indicate the cultivar used or the provenance of the chickpeas. The standardization of cultivars and handling could help users increase their success in using chickpea but this information is not available on canned chickpea products.
The objective of this research is to determine the aquafaba components that contribute foaming properties. Here,the rheological properties of aquafaba from commercial chickpea brands were compared and the chemical properties were studied by NMR, electrophoresis, and peptide mass fingerprinting. To our knowledge, this is the first research which describes the chemical composition and the functional properties of the aquafaba viscosifier components.

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			<td height="21" style="height:21px;width:219px;">Acetonitrile</td>
			<td style="width:217px;">Fisher Scientific&#160;</td>
			<td style="width:100px;">L14734</td>
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			<td height="21" style="height:21px;width:219px;">Formic acid&#160;</td>
			<td style="width:217px;">Sigma-Aldrich</td>
			<td style="width:100px;">33015-500mL</td>
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			<td height="42" style="height:42px;width:219px;">Mass spectrometry vial&#160;</td>
			<td style="width:217px;">Agilent Technologies Canada Ltd.</td>
			<td style="width:100px;"></td>
			<td style="width:267px;"></td>
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		<tr height="63">
			<td height="63" style="height:63px;width:219px;">Agilent 6550 iFunnel quadrupole time-of-flight mass spectrometer&#160;</td>
			<td style="width:217px;">Agilent Technologies Canada Ltd.</td>
			<td style="width:100px;"></td>
			<td style="width:267px;">Agilent 1260 series LC instrument and Agilent Chip Cube LC-MS interface</td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:219px;">HPLC-Chip II: G4240-62030 Polaris-HR-Chip_3C18&#160;</td>
			<td style="width:217px;"></td>
			<td style="width:100px;"></td>
			<td style="width:267px;">360 nL enrichment column and 75 &#181;m &#215; 150 mm analytical column, both packed with Polaris C18-A, 180&#197;, 3 &#181;m stationary phase.&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:219px;">Agilent MassHunter Qualitative Analysis Software</td>
			<td style="width:217px;">Agilent Technologies Canada Ltd.</td>
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			<td height="42" style="height:42px;width:219px;">SpectrumMill data extractors</td>
			<td style="width:217px;">Agilent Technologies Canada Ltd.</td>
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</table>

composition and properties of aquafaba: water recovered from commercially canned chickpeas

Chickpea and other pulses are commonly sold as canned products packed in a thick solution or a brine. This solution has recently been shown to produce stable foams and emulsions, and can act as a thickener. Recently interest in this product has been enhanced through the internet where it is proposed that this solution, now called aquafaba by a growing community, can be used a replacement for egg and milk protein. As aquafaba is both new and being developed by an internet based community little is known of its composition or properties. Aquafaba was recovered from 10 commercial canned chickpea products and correlations among aquafaba composition, density, viscosity and foaming properties were investigated. Proton NMR was used to characterize aquafaba composition before and after ultrafiltration through membranes with different molecular weight cut offs (MWCOs of 3, 10, or 50 kDa). A protocol for electrophoresis, and peptide mass fingerprinting is also presented. Those methods provided valuable information regarding components responsible for aquafaba functional properties. This information will allow the development of practices to produce standard commercial aquafaba products and may help consumers select products of superior or consistent utility.

Each can of chick peas is labeled to indicate the ingredients added during canning. Ingredients included water, chick peas, salt, and disodium ethylenediamine tetraacetic acid (EDTA). In addition, two cans were labeled as &#34;may contain calcium chloride&#34;. Three distinct lining colours were observed; white, clear yellow and metallic (Table 1).
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Watch this Scientific Journal Video about Composition and Properties of Aquafaba: Water Recovered from Commercially Canned Chickpeas at JoVE.com

Composition and Properties of Aquafaba: Water Recovered from Commercially Canned Chickpeas

Aquafaba is a viscous juice from canned chickpea that, when stirred vigorously, produces a relatively stable white froth or foam. The primary research goal is to identify the components of aquafaba that contribute viscosifying/thickening properties using nuclear magnetic resonance (NMR), ultrafiltration, electrophoresis, and peptide mass fingerprinting.

Chickpea and other pulses are commonly sold as canned products packed in a thick solution or a brine. This solution has recently been shown to produce ...

My name is Martin Reaney. I'm Chair of Lipid Quality and Utilization at the University of Saskatchewan, Department of Agriculture and Bioresources. Pulses and pulse fractions have been recently used as milk and egg replacements.For this purpose, we investigated the use of aquafaba for milk and egg replacement. Aquafaba is the water remaining from canned chickpeas. This water contains components that can thicken food products and stabilize food foams and emulsions.There are many recipes on the internet which describe the use of aquafaba in food products. However, people often report that they could not repeat recipes that they found on the internet and achieve the same properties of aquafaba that other users have achieved. The overall goal of our study was to investigate the correlation between aquafaba composition, density, viscosity and foaming properties.NMR and electrophoresis were used to study aquafaba composition. There is a procedure used by all manufacturers producing canned chickpeas. This involves first sorting the seed for quality to remove undesirable seed.Optionally, the seed is rinsed with water to remove surface contamination. For our purposes, the seed is submerged in water for a few seconds and then the water is immediately drained. After the seed is rinsed, the seed is immersed in two volumes of water or more to allow it to expand and fully hydrate.This soaking is called steeping. After soaking, the seeds have expanded and are ready to can. The seeds are comparatively softer and more fragile and must be handled appropriately.This involves, first of all, sorting the seeds for quality to remove undesirable seeds, then it follows that the seeds would be soaked in water. First they're rinsed and then soaked for a period of time, as you can see here. After soaking, they will have greatly expanded in volume and they are ready for canning.After steeping the seeds, we pour the soaked seed through a sieve. Water going through the sieve is discarded. The seed is transferred to a 300mL can with a large spoon such as this one here.The can is filled with water to within one centimeter of the top so that sufficient room is available for expansion. The canning lid was placed on top of the can and placed in the can sealer as demonstrated. The sealer is operated by pressing down on the handle to force the lid into contact with the can during sealing.The hand crank on the sealer is turned to both spin the can and to seal the can with two die that shape the lid and fix it to the can. Once the can is sealed, the die retracts and the can is readily removed. The can's seal should be watertight.Then, the sealed can is placed in a pressure cooker. Water is added to the cooker to fill it to about four centimeters deep. The cooker is sealed by placing the lid on the cooker and rotating it until it is sealed as shown.For pulses, the cooking time is a period of 75 minutes at 115 degrees centigrade. After cooking the peas, we have to take them out and separate the peas from the aquafaba. We open this with a standard can opener.Now that the can is open, we can place the contents of the can in a colander that is put in a larger collection vessel. The aquafaba juice goes through the colander and can be separated that way from the peas in the can. It's this liquid that we use for further experiments.So, that's aquafaba of two minutes. Here, you can see the type of foam we would use for further studies. In this study, we used commercial cans from 10 different commercial sources as our sources of aquafaba.After blending for two minutes, the foam was placed in plastic cups and observed over time. As you can see, the foam is collapsing in all the cups. Only two samples, D and H, produced a stable foam that lasted throughout the entire experiment.All of the other foams collapsed over time. At zero hours, all cups were full of foam. After one hour, separation of liquid was evident in all samples except Sample H.After 14 hours, some of the liquid had separated from Sample H.We further wanted to characterize aquafaba from canned peas.We looked at gross characteristics, mass balance, including looking at the content of chickpea seeds, juice volume, juice density and juice viscosity. The correlations among these properties were also investigated. Unsurprisingly, there was a strong negative correlation between chickpea fresh weight and juice volume.There was a strong positive correlation between chickpea fresh weight and aquafaba viscosity. Aquafaba samples were prepared for NMR spectroscopy. The aquafaba, shown here as juice, was centrifuged of 9200g in an Eppendorf tube for 10 minutes.The supernatant was taken up from the Eppendorf tube in a one mL slope syringe as seen here. Then about four or five micron filters attached to the Luer-Lok on the syringe. We found that the filtration required some application of force to expel the sample.Once the sample is filtered, it is possible to use it for NMR spectrometry. Here, the sample is being transferred to an NMR tube. Later, deuterated water will also be added to the sample to allow the NMR spectrometer to lock to its frequency.Based on the NMR resonances observed, it is possible to determine the compounds that are present in aquafaba. We were able to observe compounds that reflected conditions experienced by the chickpea during processing. For example, conditions during steeping might allow anoxic respiration by the seed or microorganisms present.We observed compounds such as lactic and acetic acid that are likely formed during steeping. We also observed compounds that likely leach from the seed during cooking. These includes compounds such as choline and sugars.The supernatant was also used for peptide mass fingerprinting after removing low molecular weight species. In this case, the chickpea liquid was placed in a centrifugal unit with a three kilodalton membrane. The centrifugal unit was used to centrifuge it at 3900 times g for two hours.The retentate of this centrifugation was used for SDS-PAGE analysis. After standard separation of the proteins by SDS-PAGE, the gel was stained using Coomassie Blue. Intensely stained bands were then cut from the gel, destained, subject to tryptic digestion and the digestion fragments were analyzed using LC-mass spectrometry, Protein mass spectrometry software was used to deduce the sequences of proteins present.Most of the proteins present appear to be chickpea, but a few high molecular weight proteins are present that are due to microbial contamination from the chickpea disease organism, Ascochyta blight. The majority of proteins identified are well-known, heat stable proteins, including dehydrants, late embryo abundant proteins and defensins. Additives to chickpea include salt, disodium ADT and calcium chloride.The can linings that we observed were white, clear yellow or metallic. Chickpea fresh weight is positively correlated to its juice viscosity and the VF/VJ ratio. This relationship is largely related to the samples without an AZL added.These samples have a much higher viscosity, but much lower VF/VJ than other samples. Chickpea fresh weight and juice volume are easily determined by consumers. We observed a negative correlation between juice density and volume increase ratio.The foam formed from aquafaba samples derived from chickpeas cooked with salt had much greater stability. Aquafaba contains proteins with molecular weights that are greater than three kilodaltons. End of our analysis shows the presence of substances in chickpeas, for example choline, and also compounds that might accumulate during soaking the peas due to action of bacteria or seed metabolism, such as acetic acid and lactic acid.Electrophoresis and peptide mass fingerprinting has allowed a preliminary characterization of proteins present.

composition-properties-aquafaba-water-recovered-from-commercially

Research

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Environment

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) loading from lake sediments can account for a substantial portion of the total P load in eutrophic, and some mesotrophic, lakes. Laboratory determination of P release rates from sediment cores is one approach for determining the role of internal P loading and guiding management decisions. Two principal alternatives to experimental determination of sediment P release exist for estimating internal load: in situ measurements of changes in hypolimnetic P over time and P mass balance. The experimental approach using laboratory-based sediment incubations to quantify internal P load is a direct method, making it a valuable tool for lake management and restoration.
Laboratory incubations of sediment cores can help determine the relative importance of internal vs. external P loads, as well as be used to answer a variety of lake management and research questions. We illustrate the use of sediment core incubations to assess the effectiveness of an aluminum sulfate (alum) treatment for reducing sediment P release. Other research questions that can be investigated using this approach include the effects of sediment resuspension and bioturbation on P release.
The approach also has limitations. Assumptions must be made with respect to: extrapolating results from sediment cores to the entire lake; deciding over what time periods to measure nutrient release; and addressing possible core tube artifacts. A comprehensive dissolved oxygen monitoring strategy to assess temporal and spatial redox status in the lake provides greater confidence in annual P loads estimated from sediment core incubations.

Lake eutrophication is a water quality issue worldwide, making the need to identify and control nutrient sources critical. Laboratory determination of phosphorus release rates from sediment cores is a valuable approach for determining the role of internal phosphorus loading and guiding management decisions.

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) ...

EPA Method 1615. Measurement of Enterovirus and Norovirus Occurrence in Water by Culture and RT-qPCR. Part III. Virus Detection by RT-qPCR

EPA Method 1615 measures enteroviruses and noroviruses present in environmental and drinking waters. This method was developed with the goal of having a standardized method for use in multiple analytical laboratories during monitoring period 3 of the Unregulated Contaminant Monitoring Rule. Herein we present the protocol for extraction of viral ribonucleic acid (RNA) from water sample concentrates and for quantitatively measuring enterovirus and norovirus concentrations using reverse transcription-quantitative PCR (RT-qPCR). Virus concentrations for the molecular assay are calculated in terms of genomic copies of viral RNA per liter based upon a standard curve. The method uses a number of quality controls to increase data quality and to reduce interlaboratory and intralaboratory variation. The method has been evaluated by examining virus recovery from ground and reagent grade waters seeded with poliovirus type 3 and murine norovirus as a surrogate for human noroviruses. Mean poliovirus recoveries were 20% in groundwaters and 44% in reagent grade water. Mean murine norovirus recoveries with the RT-qPCR assay were 30% in groundwaters and 4% in reagent grade water.

Here we present a procedure to quantify enterovirus and norovirus in environmental and drinking waters using reverse transcription-quantitative PCR. Mean virus recovery from groundwater with this standardized procedure from EPA Method 1615 was 20% for poliovirus and 30% for murine norovirus.

EPA Method 1615 measures enteroviruses and noroviruses present in environmental and drinking waters. This method was developed with the goal of having a ...

Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample

Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future energy resources and energy storage media. To develop a method for gas production from natural MH-bearing sediments and hydrate-based technologies, it is imperative to understand the thermal properties of gas hydrates.
The thermal properties' measurements of samples comprising sand, water, methane, and MH are difficult because the melting heat of MH may affect the measurements. To solve this problem, we performed thermal properties' measurements at supercooled conditions during MH formation. The measurement protocol, calculation method of the saturation change, and tips for thermal constants' analysis of the sample using transient plane source techniques are described here.
The effect of the formation heat of MH on measurement is very small because the gas hydrate formation rate is very slow. This measurement method can be applied to the thermal properties of the gas hydrate-water-guest gas system, which contains hydrogen, CO2, and ozone hydrates, because the characteristic low formation rate of gas hydrate is not unique to MH. The key point of this method is the low rate of phase transition of the target material. Hence, this method may be applied to other materials having low phase-transition rates.

We present a protocol for measuring the thermal properties of synthetic hydrate-bearing sediment samples comprising sand, water, methane, and methane hydrate.

Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future ...

Screening for Endocrine Activity in Water Using Commercially-available In Vitro Transactivation Bioassays

In vitro transactivation bioassays have shown promise as water quality monitoring tools, however their adoption and widespread application has been hindered partly due to a lack of standardized methods and availability of robust, user-friendly technology. In this study, commercially available, division-arrested cell lines were employed to quantitatively screen for endocrine activity of chemicals present in water samples of interest to environmental quality professionals. A single, standardized protocol that included comprehensive quality assurance/quality control (QA/QC) checks was developed for Estrogen and Glucocorticoid Receptor activity (ER and GR, respectively) using a cell-based Fluorescence Resonance Energy Transfer (FRET) assay. Samples of treated municipal wastewater effluent and surface water from freshwater systems in California (USA), were extracted using solid phase extraction and analyzed for endocrine activity using the standardized protocol. Background and dose-response for endpoint-specific reference chemicals met QA/QC guidelines deemed necessary for reliable measurement. The bioassay screening response for surface water samples was largely not detectable. In contrast, effluent samples from secondary treatment plants had the highest measurable activity, with estimated bioassay equivalent concentrations (BEQs) up to 392 ng dexamethasone/L for GR and 17 ng 17&#946;-estradiol/L for ER. The bioassay response for a tertiary effluent sample was lower than that measured for secondary effluents, indicating a lower residual of endocrine active chemicals after advanced treatment. This protocol showed that in vitro transactivation bioassays that utilize commercially available, division-arrested cell &#34;kits&#34;, can be adapted to screen for endocrine activity in water.

Screening for Endocrine Activity in Water Using Commercially-available In Vitro Transactivation Bioassays

A protocol to screen for endocrine activity in organic extracts of water samples, including treated wastewater effluent and surface (receiving) water, was adapted using commercially available division-arrested ("freeze and thaw") in vitro transactivation bioassays.

In vitro transactivation bioassays have shown promise as water quality monitoring tools, however their adoption and widespread application has been ...

Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type Analysis

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets, analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy. The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.

Microplastics act as vector of potentially toxic organic contaminants with unpredictable effects. This protocol describes an alternative methodology for assessing the levels of organochlorine pesticides adsorbed on plastic pellets and identifying the polymer chemical structure. The focus is on pressurized fluid extraction and attenuated total reflectance Fourier transform infrared spectroscopy.

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment ...

Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage discharge events. Farm canals can be enriched by nutrients such as phosphorus (P) that are susceptible to transport. Phosphorus in the form of suspended particulates can significantly contribute to the overall P loads in drainage water. A settling tank experiment was conducted to capture suspended particulates during discrete drainage events. Farm canal discharge water was collected in a series of two 200 L settling tanks over the entire duration of the drainage event, so as to represent a composite subsample of the water being discharged. Imhoff settling cones are ultimately used to settle out the suspended particulates. This is achieved by siphoning water from the settling tanks via the cones. The particulates are then collected for physico-chemical analyses.

Nutrients present in particulate form can contribute significantly to the overall loads in agricultural drainage waters. This study describes a novel method to capture flow-weighted water and suspended particulates from farm canal drainage over the entire duration of the drainage event.

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage ...

Construction of a Low-cost Mobile Incubator for Field and Laboratory Use

Incubators are essential for a range of culture-based microbial methods, such as membrane filtration followed by cultivation for assessing drinking water quality. However, commercially available incubators are often costly, difficult to transport, not flexible in terms of volume, and/or poorly adapted to local field conditions where access to electricity is unreliable. The purpose of this study was to develop an adaptable, low-cost and transportable incubator that can be constructed using readily available components. The electronic core of the incubator was first developed. These components were then tested under a range of ambient temperature conditions (3.5 &#176;C - 39 &#176;C) using three types of incubator shells (polystyrene foam box, hard cooler box, and cardboard box covered with a survival blanket). The electronic core showed comparable performance to a standard laboratory incubator in terms of the time required to reach the set temperature, inner temperature stability and spatial dispersion, power consumption, and microbial growth. The incubator set-ups were also effective at moderate and low ambient temperatures (between 3.5 &#176;C and 27 &#176;C), and at high temperatures (39 &#176;C) when the incubator set temperature was higher. This incubator prototype is low-cost (&lt; 300 USD) and adaptable to a variety of materials and volumes. Its demountable structure makes it easy to transport. It can be used in both established laboratories with grid power or in remote settings powered by solar energy or a car battery. It is particularly useful as an equipment option for field laboratories in areas with limited access to resources for water quality monitoring.

This paper describes a method for building an adaptable, low-cost and transportable incubator for microbial testing of drinking water. Our design is based on widely available materials and can operate under a range of field conditions, while still offering the advantages of higher-end laboratory-based models.

Incubators are essential for a range of culture-based microbial methods, such as membrane filtration followed by cultivation for assessing drinking water ...

Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions

Variable microorganisms in particulate matter (PM) under different environmental conditions may have significant impacts on human health. In this study, we described a protocol for multiple analyses of the biological compositions in environmental PM. Five experiments are presented: (1) PM number monitoring by using a laser particle counter; (2) PM collection by using a cyclonic aerosol sampler; (3) PM collection by using a high-volume air sampler with filters; (4) culturable microbes collection by the Andersen six-stage sampler; and (5) detection of biological composition of environmental PM by bacterial 16SrDNA and fungal ITS region sequencing. We selected hazy days and a livestock farm as two typical examples of the application in this protocol. In this study, these two sampling methods, cyclonic aerosol sampler and filter sampler, showed different sampling efficiency. The cyclonic aerosol sampler performed much better in terms of collecting bacteria, while these two methods showed the same efficiency in collecting fungi. Filter samplers can work under low temperature conditions while cyclonic aerosol samplers have a sampling limitation for temperature. A solid impacting sampler, such as an Andersen six-stage sampler, can be used to sample bioaerosols directly into the culture medium, which increases the survival rate of culturable microorganisms. However, this method mainly relies on culture while more than 99% of microbes cannot be cultured. DNA extracted from the culturable bacteria collected by the Andersen six-stage sampler and samples collected by cyclonic aerosol sampler and filter sampler were detected by bacterial 16S rDNA and fungal ITS region sequencing.All the methods above may have wide application in many fields of study, such as environmental monitoring and airborne pathogen detection. From these results, we can conclude that these methods can be used under different conditions and may help other researchers further explore the health impacts of environmental bioaerosols.

Understanding the biological composition of environmental particulate matter is important for the study of its significant impacts on human health and disease spread. Here, we used three types of bioaerosol sampling methods and a biological analysis of airborne microbes to better explore airborne microbial communities under different environmental conditions.

Variable microorganisms in particulate matter (PM) under different environmental conditions may have significant impacts on human health. In this study, ...

Xylem Water Distribution in Woody Plants Visualized with a Cryo-scanning Electron Microscope

A scanning electron microscope installed cryo-unit (cryo-SEM) allows specimen observation at subzero temperatures and has been used for exploring water distribution in plant tissues in combination with freeze fixation techniques using liquid nitrogen (LN2). For woody species, however, preparations for observing the xylem transverse-cut surface involve some difficulties due to the orientation of wood fibers. Additionally, higher tension in the water column in xylem conduits can occasionally cause artifactual changes in water distribution, especially during sample fixation and collection. In this study, we demonstrate an efficient procedure to observe the water distribution within the xylem of woody plants in situ&#160;by using a cryostat and cryo-SEM. At first, during sample collection, measuring the xylem water potential should determine whether high tension is present in the xylem conduits. When the xylem water potential is low (&#60; ca. &#8722;0.5 MPa), a tension relaxation procedure is needed to facilitate better preservation of the water status in xylem conduits during sample freeze fixation. Next, a watertight collar is attached around the tree stem and filled with LN2&#160;for freeze fixation of the water status of xylem. After harvesting, care should be taken to ensure that the sample is preserved frozen while completing the procedures of sample preparation for observation. A cryostat is employed to clearly expose the xylem transverse-cut surface. In cryo-SEM observations, time adjustment for freeze-etching is required to remove frost dust and accentuate the edge of the cell walls on the viewing surface. Our results demonstrate the applicability of cryo-SEM techniques for the observation of water distribution within xylem at cellular and subcellular levels. The combination of cryo-SEM with non-destructive in situ observation techniques will profoundly improve the exploration of woody plant water flow dynamics.

Observing the water distribution within the xylem provides significant information regarding water flow dynamics in woody plants. In this study, we demonstrate the practical approach to observe xylem water distribution in situ&#160;by using a cryostat and cryo-SEM, which eliminates artifactual changes in the water status during sample preparation.

A scanning electron microscope installed cryo-unit (cryo-SEM) allows specimen observation at subzero temperatures and has been used for exploring water ...

Using Deuterium Oxide as a Non-Invasive, Non-Lethal Tool for Assessing Body Composition and Water Consumption in Mammals

Body condition scoring systems and body condition indices are common techniques used for assessing the health status or fitness of a species. Body condition scoring systems are evaluator dependent and have the potential to be highly subjective. Body condition indices can be confounded by foraging, the effects of body weight, as well as statistical and inferential problems. An alternative to body condition scoring systems and body condition indices is using a stable isotope such as deuterium oxide to determine body composition. The deuterium oxide dilution method is a repeatable, quantitative technique used to estimate body composition in humans, wildlife, and domestic species. Additionally, the deuterium oxide dilution technique can be used to determine the water consumption of an individual animal. Here, we describe the adaption of the deuterium oxide dilution technique for assessing body composition in big brown bats (Eptesicus fuscus) and for assessing water consumption in cats (Felis catis).

This article describes the deuterium oxide dilution technique in two mammals, an insectivore and carnivore, to determine total body water, lean body mass, body fat mass, and water consumption.