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Like I would like to get help with the steps in writing a practical report
Regarding the above question.......
Thank you
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for practical report, it includes the following standard steps
F o r d e t e r m i n a t i o n o f m o i s t u r e c o n t e n t , t h e s a m p l e i s d r i e d t o a c o n s t a n t w e i g h t i n a n h o t a i r o v e n w h i c h d o n o t d e c o m p o s e a t 7 0 - 1 0 0 o C ( a b o u t 70 o C f r u i t s a n d 1 0 0 o C v e g e t a b l e s ) .
R e q u i r e m e n t s :
F o o d S a m p l e , H o t a i r O v e n , W e i g h i n g b a l a n c e , M o i s t u r e d i s h e s ,
D e s i c c a t o r , e t c .
P r o c e d u r e :
1 . T a k e k n o w n a m o u n t ( 30 - 50 gram ) o f t h e f r u i t / v e g e t a b l e / f o o d
s a m p l e
2 . D r y t h e m o i s t u r e d i s h a n d l i d i n h o t a i r o v e n a t 7 0 - 1 0 0 o C a n d c o o l i n a d e s i c c a t o r s .
3 . T a k e t h e d r y d i s h a n d n o t e t h e t a r e w e i g h t .
4 . K e e p t h e s a m p l e i n d i s h .
5 . T h e n k e e p t h e s a m p l e s i n t h e o v e n a t 7 0 - 100 o C f o r 1 2 h o u r s .
6 . T a k e o u t t h e s a m p l e f r o m o v e n , p l a c e i n a d e s i c c a t o r s a n d c o o l .
7 . A g a i n w e i g h t h e d i s h e s a l o n g w i t h d r i e d s a m p l e .
8 . A g a i n d r y t h e s a m p l e t i l l c o n s t a n t w e i g h t i s a c h i e v e d .
9 . N o t e d o w n t h e f i n a l w e i g h t o f t h e s a m p l e ( a s h )
10 . M a k e c a l c u l a t i o n s .
C a l c u l a t i o n s :
% M o i s t u r e = F r e s h w e i g h t ( W 1 ) – D r y w e i g h t ( W 2 ) x 1 0 0
F r e s h w e i g h t ( W 1 )
% D r y m a t t e r / T o t a l s o l i d = D r y w e i g h t x 1 0 0
F r e s h w e i g h t
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For measuring somatic cells and analysing milk constituents
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for your help
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Hello, I am looking to perform a colorimetric protein assay (Bradford/BCA etc.) to compare the protein content of different potato varieties, but I would like to use a different model protein besides BSA and gamma globulin to prepare my standard curve. Are there any plant-based proteins that can be used for this purpose? 
Also what criteria are needed to be fulfilled in order to select a non-established protein (i.e anything besides BSA) for use as a standard? Thank you!
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BSA is used beacsue it readily available from lab supplier and compareable across all experiments. Its not usually even comparable to the protein your observing, its just a standard tool used to compare and repeat.
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I am in search of methods of quantitative and qualitative estimation of cellulase in a food sample(biological sample)?
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Can anyone suggest me a bioinformatics approach to identify a mutation if it is naturally occurred or created by genetic engineering. For GMO and food analysis it is required.
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With a small team we are currently researching on nouvelle Jewish-Israeli cuisine as a worldwide trend and hence as a social-anthropological modern phenomenon. Your contribution could help analyze and describe a complex and ever changing food-culture.
Understanding processes that shape our cultures and identities is key.
Thank you.
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تم اخراج اليهود من بلدي في الستينات من القرن العشرين
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Good Morning researcher, I'm a student currently on project to debitter the soy milk hydrosylates. But the problem is the soy milk hydrosylates is not bitter. So im asking if this protein content effect the bitterness? Im using papain enzyme to hydrolyse the soy milk, and how much concentration does it need to hydrolyse it?? Thank you!!
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Sometime, other phytochemicals present in the soya bean milk may be responsible for the bitterness of Soya milk
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Hello people,
I'm using sigma's TDF-100A kit for the assay of total dietary fiber. However, it's taking a vary long time to filtrate the fibers after precipitation in ethanol. Sometimes the washing solvents just get stuck in the crucible and I cant finish the filtration . Does anyone have any tips to share about this procedure?
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If you read the labels on food, you'll see the words "natural flavoring" or "artificial flavoring". The initial impression may be that the first must be good, while the second must be bad but if we look at what natural & artificial really mean in practice, most natural & artificial flavors are exactly the same chemical compounds, differing only by their source and both natural & artificial chemicals are or will be purified in a lab.
Is natural really better or safer or more tasty than artificial?
In some cases, natural flavoring may be more dangerous than artificial flavoring (e.g., natural flavor extracted from almonds can contain toxic cyanide but the artificial flavor has the taste but does not have cyanide).
Few years ago, my students prepared natural & artificial strawberry jams in a practical course. The taste of the artificial was judged to be better unanimously by the technician, my students & me.
Few years ago, a colleague's students made real strawberry ice cream & artificially- flavored strawberry ice cream. I tasted both & the second was more delicious, for me.
These two observations puzzled me. I know something about flavoring but I am not a full-fledged expert so I am asking to learn: Are natural flavorings really better & safer than the artificial counterparts? Is the public health at risk upon consuming foods & drinks with artificial flavors?
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The term natural flavor or natural flavoring means the essential oil, oleoresin, essence or extractive, protein hydrolysate, distillate, or any product of roasting, heating, or enzymolysis, which contains the flavoring constituents derived from a spice, etc. Artificial flavors, on the other hand, are made from anything else that doesn't fall under the "natural" umbrella. Interestingly, both types of flavors are made in the lab by scientists called "flavorists," who blend various chemicals together. The flavorist creating an artificial flavoring must use the same chemicals in his formulation as would be used to make a natural flavoring, however. Otherwise, the flavoring will not have the desired flavor. Although "natural" sure sounds better than "artificial," ingredients that come from nature aren't always safer than those that are artificially made. There are many deadly toxins that are produced in nature. In addition, artificial flavorings are simpler in composition and potentially safer because only safety-tested components are utilized. Besides health effects, natural flavors also may have more negative environmental impacts than artificial flavors. An example of massoia lactone, which is used for a creamy, coconut, spicy flavor. Harvesting it from the massoia tree in Malaysia kills the tree because harvesters have to remove the bark. In other cases collecting natural flavors involves clear-cutting and carbon emissions, which doesn't happen when flavors are created in the lab.
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What are the common adulterants in commercial honey? how to identify pure honey and adulterated honey with the help of NMR spectroscopy? Is there any other technique to check purity of honey?
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On the NMR spectrum of high-quality honey, the signal from sucrose will be
weak, and in the honey of bees that were artificially fed with
honey, the signal from sucrose will be significant
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I used to notice in our food culture in Iraq that a person who suffers from anemia or loses blood is advised to eat celery with the spleen, and I did not know the reason until after my academic studies of plant pigments (chlorophyll) and the Similarity large between them and hemoclobin, as well as that the spleen is the cemetery of iron.
How can some customs and traditions be correct even though at the time of their spread there was no great scientific progress as is the case at the present time?
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Hemoglobin is the red pigment in blood that is capable of transporting oxygen Chlorophyll is the green pigment in plants and certain organisms that is capable of trapping the energy of the sun to enhance the process of photosynthesis.
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Please let me know about how to analyse pollen in honey in a simple and specified manner
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This method is recommended by the International Commission for Bee Botany:
Ten grams of honey is dissolved in 20 ml of warm water (40 C).
The solution is centrifuged for 10 min at 2500 r/min, the supernatant solution is decanted, and the sediments are collected into a conical tube and treated with an acetolysis mixture (acetic anhydride : conc. sulphuric acid = 9:1 V/V) for approximately 30 min at room temperature.
After treatment with the acetolysis mixture, the sediments are rinsed with distilled water, centrifuge for 5 min at 2500 r/min, and preserve for study.
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In most of the food analysis procedures, before the chemical analysis of vegetables/foods are oven-dried at 50-60 centigrade temperature. Does it affect the nutrition content in the sample?
Thanks! Any help is appreciated!
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I want to know the most important application of GC/MS in food analysis and the most common columns suitable for general applications of GC/MS.
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Hi,
I've been reading around GC for use in food analysis (quality, taste, aromas) and was wondering if there any great benefit of combining FTIR and MS in one system.
I understand the complementary information from both methods on isomer structures for example. Recently, literature uses dedicated GC-MS and GC-FTIR. So, I was wondering if this is because:
1. FTIR spectra are rarely needed for general research.
2. System setup is so much simpler when separated that it's worth the money to get a dedicated system.
3. Combining the two is a hell of a task (synchronization?) and not worth any money.
4. Combining the two isn't effective (sampling speed, LOD, type of things)
I might be missing something important as I haven't worked with GC yet.
I found the topic quite interesting as a "pastime read", so I'd appreciate any views. Maybe somebody with experience from the 80s? From what I found it was quite a thing back then.
Thanks
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One possibility is to prepare a sample at higher concentration for the FTIR and then use a splitter at the effluent side of the GC that is in a ratio to provide a vast majority of sample to the FTIR and the rest to the MS. So this would be a single GC with a splitter to both FTIR and MS. They would be in parallel, not tandem.
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Pineapple juice contains not only sucrose but also glucose, fructose, etc.. I wonder if by determining the degrees Brix of a sample of pineapple juice, i will obtain only the sucrose content of the sample, or if i will obtain the content of all the mono and disacharides of the sample.
Thanks in advance for your answers
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Degrees Brix (symbol °Bx) is the sugar content of an aqueous solution. One degree Brix is 1 gram of sucrose in 100 grams of solution and represents the strength of the solution as percentage by mass. If the solution contains dissolved solids other than pure sucrose, then the °Bx only approximates the dissolved solid content. The °Bx is traditionally used in the wine, sugar, carbonated beverage, fruit juice, maple syrup and honey industries.
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Potassium Sorbate added to cheese with low pH due to the presence of lactic acid; does lactic acid act the same as HCL to convert Potassium Sorbate to Sorbic.
Also, potassium Sorbate added to brine ( saturated water with salt 10% at 4 C degrees)
How you think these conditions will affect the equilibrium between potassium Sorbate to Sorbic acid.
The problem in food industry labs they rely on outside labs to test and analyze samples for all out of ordinary tests and I've been trying to find a lab to analyze Potassium Sorbate separate from Sorbic acid but they only test Sorbate by HPLC which doesn't give an idea how much of each component is in that sample.
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There are several other separation methods published for the detection of sorbic acid in foodstuffs. These include HPLC (Saad et al., 2005; FSIS, 2004), spectrophotometric (Campos et al., 1991), micellar electrokinetic chromatography (Boyce, 1999), and CE (Özteki̇n, 2018).
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I am conducting a meta-analysis and most of my studies report values for bacterial analysis in CFU. However, I have one study which reports its microbial values in MPN. What should I do?
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The simple answer is that they are equivalent- one MPN is equal to one CFU. Both units measure the estimated number of bacteria in a water sample. Both are recognized by a variety of scientific and regulatory bodies worldwide including the US Environmental Protection Agency (EPA) and the International Standardization Organization (ISO). The difference is in how the measurement is obtained. The use of either MPN or CFU is based on the method used for the detection of bacteria and both are valid measurements for bacteria limits.
For CFUs, bacteria grow on a solid medium, like agar.  Afterward, colonies of bacteria are counted.  For an MPN measurement, samples grown in a liquid medium, like multiple tube fermentation and Colilert.  Positive wells/tubes are then counted and an MPN conversion table is used to generate a numeric result.  
In short, laboratories and agencies worldwide use both MPN and CFU interchangeably. 
Both measurements are well-established means to estimate the number of bacteria in a sample, and both carry a 95% confidence interval.  
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I'm planning to start with a project of a laboratory that makes microbiological analysis to food industry. I'm plan to buy some second-hand equipment to make less hard the initial investment. Is it recommended? Wich providers are recommended?
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Before deciding to buy equipment yourself you might want to check out Clustermarket ( www.clustermarket.com ) - it's an online equipment/service sharing platform where you can get access to equipment in institutions nearby.
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Rice is the seed of the grass species Oryza sativa (Asian rice) or Oryza glaberrima (African rice). As a cereal grain, it is the most widely consumed staple food for a large part of the world's human population, especially in Asia. It is the agricultural commodity with the third-highest worldwide production (rice, 741.5 million tonnes in 2014), after sugarcane (1.9 billion tonnes) and maize (1.0 billion tonnes).
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Hey Mohammed Shaker Hossain; After conducting all the necessary trials which involve Stage I, Stage II, Preliminary Yield, advanced Yield Trials, Multi-location trials for the target traits of interests, You need data on DUS which is Distinctness, Uniformity and Stability for this variety and it is supposed to be different from the existing varieties that have been released before. You can even go further to genotype it to develop it's fingerprint for reference in case you want to do a QC/QA.
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I'm doing a study by using honey as my main treatment substance. The problem with honey is, honey collected from different sources have different physicochemical characteristic and its ingredient is also different. Does each honey sources need to undergo separate toxicity test? Human have consume honey for thousand of years and we can relatively say it is safe especially after rigorous standard food post-harvesting processes. 
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I obtained useful information from your reply on this RG question,
Regards for all
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I used Microwave Plasma-Atomic Emission Spectrometry (MP-AES) to analyse mineral content of various foods. How to calculate how much of a given mineral is in 100g?
I used 25g of food which has been ashed and treated with HCl, then turned into a solution of a total volume 100ml. Initial solution was too concentrated so I had to dilute it and I made a 1 in 100 dilution = 1ml of my initial solution + 99ml of deionised water.
How do I work out how much of a given mineral is in 100g of analysed food sample? For example, one of my results for Selenium from the MP-AES was 8.43 mg/L
Thank you for your help
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Hi
Regarding to the dilution,when there is 8.43 mg/L Se , it means there was 8.43 x 100 mg/l in initial solution. According to the total volume(100 ml) you can calculate the amount of Se in food. after calculation ( Stoichiometry ) it is found that 84.3 mg of Se exist in 25 gr food.
So now the Se in 100 gr of food can be calculated by a simple fit ratio:
I think the answer would be 337.2 mg Se ((100 (gr food) * 84.3 mg Se / 25 gr food) Martynas Saczuk
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Hello,
I am aware of FDA being the reference institution for food production control. However, I am not sure which guidance in particular defines the testing which are required to be performed?
Thanks,
Antonio
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Olabisi Abidemi Adekalu any references to the AOAC manual?
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This because table sugar is extracted naturally from sugar cane or sugar beets and hydrolyzed to glucose and fructose and never could reach the body cells in its origin form. The hydrolysis process occurs in mouth, stomach and small intestine which the products of sucrose in body may be in a similar manner to that of honey and bread. In other words, sucrose is a carbohydrate that occurs naturally in every fruit and vegetable. But, why there is no similar propaganda to the not natural synthesized chemical candy such as aspartame and so on.
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Hi there,
I think this one question is actually a combination of various different questions and assumptions.
The fact that sugar is extracted from "natural sources" such as sugar beets and sugar cane does not mean that it "good", just because of its natural origin. Likewise, you cannot say that "artificial" sweeteners are "bad", just because they are "artifical". You probably also would not say that cocain is a good thing, just because it can be extracted from plants....
In my opinion the problem is that in the modern Western diet, people consume extremely high amounts of fat and sugar. There is also an increasing use of high-fructose-corn syrup and similar products. If you buy, for example, a modern joghurt with fruit (flavour), it contains > 10% sugar. If you look at "sweets" for kids, they often contain 30% - 50% of sugar. Therefore, the "density" of sugar much higher that in fruits or vegetables.
It is probably difficult to eat so many fruits and vegetables to get similar amounts of sugar. But if you would, for example by eating huge amounts of honey and dates every day, this also would not be good for your health. At least in Europe, nutritionists warn people that also intake of too much "natural sugar" (milk products, fruit juices) can cause health problems.
You also mentioned sweeteners such as aspartam and asked why nobody is complaining about them. First of all, these products are much sweeter than sucrose or fructose, so there are much smaller amounts used. Second, there are people in both Europe and the US who warn customers not to use such products.
In summary, I would say that eating huge amounts of sugar is not good for your health, no matter if it comes from fruit, vegetables or modern "convenince foods". The peoblem seems to be that modern food is just unnaturally high in sugar and people, therefore, consume much lager amounts of sure than decades ago.
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I hardly find a paper which involves free amino acid estimation. Instead what I get is total amino acid estimation using hydrolysis procedure. So I doubt there are free amino acids present in cereals. Please share your experience here if any.
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Hello Balaji,
We will like to know if you have given it a go on the determination of free amino acids of either wheat or rice. If you have how did it go?
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Food waste occurs due to over-production and managerial errors.
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I have already answered in similar questions
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Please all . I need to know how to calculate the spike samples for food analyses . I spiked the sample before microwave digestion ( in solid phase ) i spiked 5 ppb and i get instrument result of 35 ppb . How can we get recovery for that ?
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Dear Dr. Karim Mosa
Please go through the following attached file. Its may be helpful to you.
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Dear all. I have i food sample and i need to analyse lead in it . Should i choose lead 206 and lead 208 or only one is enough. If i choose the both how can i translate this in the calibration standards . Thank you
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Dear Karim Mosa
To be on the safe side, measure the three main isotopes (206, 207 and 208) and take the sum of all intensities for calibration and evaluation. If your instrument software does not provide a method for summing ion signals, do it off-line. Also use certified reference materials and make spike additions to selected samples to verify that the calibration is valid.
Best
Bodo
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I watched a documentary, "Rotten", that explored the various methods of honey adulteration. The high demand for honey with the sharp decline in honeybees are a concern.
Seems such practice of honey adulteration is widely practiced.
As consumers, how can we know pure honey from altered ones?
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" ( Wang, S., Guo, Q., Wang, L., Lin, L., Shi, H., Cao, H., & Cao, B. (2015). Detection of honey adulteration with starch syrup by high performance liquid chromatography. Food chemistry, 172, 669-674)
Abstract
According to saccharide profile comparison between starch syrups and pure honeys analysed through high performance liquid chromatography (HPLC), a characteristic peak was found at 15.25 min retention time in HPLC chromatogram of syrup, but no peak was observed at the same retention time in chromatogram of pure honeys. This characteristic peak for syrup was identified as an overlapping peak of oligosaccharides with more than 5 degree of polymerisation (DP) based on HPLC chromatogram comparison between starch syrup and a series of standard mono-, di- and oligosaccharides of 3–7 DP. Additionally syrup content correlated linearly with the height of the characteristic peak of syrup under different slope in two ranges 2.5–7.5% and 10–100%, respectively. Therefore, the characteristic peak at 15.25 min retention time can serve as a syrup indicator in HPLC analysis of the adulterated honeys. This new HPLC method for honey adulteration detection was further applied in an authenticity inspection on more than 100 commercial honeys. In addition to the improved accuracy of honey adulteration detection, the proposed HPLC method was simple, low cost and easy practice for honey product quality control by government department considering the popularity of HPLC device and technology".
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Need brief answers
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Follow
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I also want to understand whether DNAFoil Test kit is specific for a particular food sample, i.e being targeted for a product. For instance; Having DNAFoil Pork test kit as well as DNAFoil Beef test kit.
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I think the kits should be target specific. This technology can be applied to only organic products (plants, animals or microorganisms) that have DNA. I don't think it can be used to detect sands or presence of metals as contaminants in food.
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Hi I'm trying to analyze insoluble, soluble dietary fiber in baking products using dietary fiber kit (Megazyme).
I'm wonder whether this dietary fiber kit method measure resistant starch as an insoluble dietary or not.
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I Think professor Tranchant has said it all!
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Greetings!
I'm tryingto validate an HPLC method for the determination of phenolic compounds in vegetable matrix. There are many international guidelines available which gives the parameters and criteria for method validation (ICH, FDA, etc.) but when it comes to vegetable matrix method validation, guidelines are not quite clear (many articles doesn't even mention which guideline they used to perform the validation). So my question is:
Is there any international guideline for HPLC method validation for vegetable analysis (food matrix) ?
I will appreciate every answer and recommendations
Thank you very much!
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For sustaining my PhD thesis I need to publish 1 or more articles with ISI impact factor (total ISI value 5). I have the experimental results from my previous job and I don't have the possibility to publish trough institution, so I have to publish them myself. The field is (electro)chemistry with aplication for food analysis (MSG). Do you know any journals with low costs for publishing an article (maxim 150 $) or even free?
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This is strange, I have been publishing in Elsevier journals for a very long time (and also in electrochemistry), but I never paid ...
At the same time, there are not so many electrochemical journals with an impact factor of more than 5, I know only ELECTROCHIMICA ACTA (WOS - 5.116) and JOURNAL OF POWER SOURCES (6.945). Even JOURNAL OF THE ELECTROCHEMICAL SOCIETY has IF by WOS 3.662. Impact factors by Scopus are different, but not too much (5.01, 7.00 and 3.48 respectively).
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The result that i got is low fracturability. As I understand low fracturability indicates high crispness due to low forces needed to crack the material. However, I got confused when I found a literature that showing the result of fracturability and crispness result is moving in parallel. Hopefully, can get some clarification. Thank you!
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Hello Kamila,
I think that a clear definition of fracturability and its relationship to crispness might be of help in this context:
Fracturability is defined as the tendency of a material to shatter, crack, crumble or fail upon the application of a relatively small amount of force. It is usually displayed by a product of high degree of hardness and low degree of cohesiveness. A material of high fracturability has little tendency to deform before failure and usually makes a snapping sound (crisp).
In the case of foods,
Fracturability: Ability to break food into pieces when it is bitten using the incisors
Crispness: Noise generated by food during mastication
For more information, please refer to:
Paula, A. M. & Conti-Silva, A.C. (2014). Texture profile and correlation between sensory and instrumental analyses on extruded snacks. Journal of Food Engineering, 121:9-14.
Tunick, M.H. et al. (2013). Critical evaluation of crispy and crunchy textures: A review. International Journal of Food Properties, 16:949-963.
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Off-seasons vegetable offers the higher prices to the farmers. Instead of high price, people preferred off-season fruits and vegetables. It is a general perception that such fruits and vegetables are not good for health. There is any such studies proving the various negative health effects?
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Growing of off season vegetables in my knowledge don't have any negative effect on health, instead of any negative effect on health it provides the required vegetable to the consumer, although at some higher price. Such vegetables are not harmful unless some excessive chemicals used during its course of production. Growing of offseasons is very useful to marginal farmer, as it ensures their livelihood security.
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Hi I want to analyze the volatile compounds of crackers using HS-SPME-GC-MS.
I heard that people usually use both library and RI value to identify volatile compounds. I'm going to use n-alkane to calculate this RI value.But I have no idea how to inject this n-alkane standard. Do I need to use HS-SPME as well? Or analyze with direct injection?
And, as far as I know, this n-alkane is an external standard, so I do not need to add it to my sample. Is it right? Let me know if I'm wrong. I'm sorry to ask basic questions.
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Hello, if n-alkane is external standard so you do not need to add in to your sample for that you need internal standard. If you use HS-SPME for your samples so you need to use same way for your external standard for more reliable results.
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I was researching for debittering process on soy milk hydrosilate, and I'm using activated carbon to debitter it. I'm doing trial and error test and I can't find the correct method for debittering process. I'm using granulated activated carbon with comparison 0.5 - 1 gram per 1 gram protein on soy milk, and I just stir it together.
The process result are :
- Bitterness not decrease significantly
- The color of the milk is quite gray
- The taste of the milk is affected by the flavour of activated carbon
Any recommendatiom for the mash of the activated carbon, how to filter it, and how to decrease the bitterness??
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Refer this article, we clarified sweet sorghum juice to make beverage
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Our pesticide standard mix will include at least 74 compounds. I would like to spike samples with 5 to 10 well characterized pesticides. Any advice?
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Hello, spiking if preferable for all 74 pesticides that you want to analyse in your food samples to be able to calculate Recovery. Also better to use some internal standard besides of your pesticides for more reliable results. I think you should at first validate your method before use in food testing.
Above all mentioned is best practice.
But if you want to spike fro 5 to 10 pesticides you shuld chose mach different from each other for better results.
Hope this info will help you.
Good luck!
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I need a standart of 2-AP (2-acetyl-1-pyrroline) for analisis in GC/MS. Anyone ever synthesized this compound?
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On using perkin elmer ICP-MS. The lead in food is analysed with two modes , the standard mode and helium mode . But the result was totally different as it was much lower in helium mode. So what result we can report and how we be confirmed ??
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Obtain a food product with a certified content of lead. Measure the lead content in both modes and decide which mode is the best. It might be that both are widely deviating from the certified content, then you have to improve your method.
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Dear all,
I am trying to understand the diet of different fish parasites using stable isotope analysis. I have indications (isospace) that some of them are feeding directly on the fish tissues, but others on other sources (not fish tissues). How do I correct C13 and N15 for fractionation in this case? Are you aware of studies and /or correction factors applied to fish parasites?
Best regards
Alessandro Manfrin
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Parasites fractionation values in parasites are an interesting area of study. However, they are not well known (to my knowledge) but this paper does look at some cases: Unusual stable isotope fractionation patterns observed for fish host—parasite trophic relationships. If you are trying to correct for fractionation you must rely on published values or controlled laboratory studies.
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Dear all,
I am analysing the food environment of a case study, and I need data on the food store density (per capita and/or per surface area) of other cities and urban to compare my results with other contexts. Is there anybody who knows a database or a research study that collects this information?
Thanks in advance
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you can find them in GEMS/Food consumption database - http://www.who.int/nutrition/landscape_analysis/nlis_gem_food/en/
Hope you get information you need, good luck.
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Choongan Caralluma
Caralluma Tuberculata
Urdu: Chongan
English: Bitter Cress
Pushto: Pamankay
It is a wild plant used as a food. Its taste is bitter.
It is found in Africa, Saudi Arabia, India, Pakistan, Afghanistan and Southern Europe.
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Choongan Caralluma is a medicinal plant, used in Ayurveda traditional medicine. This plant has purgative action, anti-inflammatory and protein digestive action-proteolytic action of latex. The medicated thread Ksharsutra is prepared by coating the thread with latex along with turmeric and alkali of acyranthes aspera plant. Such thread is used in Hemorrhoids and mainly in Fistulous tract for slow cutting action, this Technic is now more or less universal as minimum invasive para surgical method.
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I can't find any interesting study showing such dependence reliably. Maybe someone know a interesting paper?
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Several studies have identified metals such Pb, Fe, Al, Cu and Zn in AD pathogen sis. Metal ions are known to catalyze the production of free radicals and induce mental retardation or dementia, Since several dietary polyphenols are known to chelate metals, their routine use may also be protective against the onset of AD. For details consult J Alzheimers Dis. 2010 Jan: 19 ( 4 ) : 1123 - 1139
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Dear Researchers,
In order to analyses the particle size of flour, except from the sieves method, what other methods are available and what is the preparation of the sample?
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As my answer - measure dry. To avoid swelling in water , measure in IPA (expensive and recycling needed). Get a diffraction dry accessory...
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My Column is Shimadzu SHIM PACK VP-ODS (4.6 × 150mm x 5 µm) RP
and Mobile phase is 10% Methanol
Kindly suggest
Thanks in advance
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If your HPLC procedure is just optimized, you need to perform the following experiments:
- linearity
- LOD and LOQ
- precision and trueness
- recovery
- stability (short and long-term)
For each point you need to perform 6 independent experiments.
For linearity are necessary at least 5 non zero points at different concentration levels.
Additionally for precision and trueness you need to analyse 6 times 3 QC levels (low, medium, and high and the concentrations need to be different respect the concentration levels used in linearity) obtained by spiking (with known amount) blank matrix.
All these procedures are deeply discussed at the following links:
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I want to make some testing kit-like formalin for fruits, vegetables, fish, milk etc or carbide for fruits etc.
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Formaldehyde may be detected using the following reagents:
1. Phenylhydrazine hydrochloride + acidic hexacyanoferrete (III) (pink or purple color, color intensity is proportional to formaldehyde amount).
2. Phenylhydrazine hydrochloride +acidic Potassium hexacyanoferrete(III)(pink or purple color, color intensity is proportional to formaldehyde amount).
3. Almost same as previous, addition is impregnation of Silica gel.
4. 3-methyl-2-benzothiazolone hydrazone (MBTH) + acidic Iron (III) Chloride (Blue). [Note: highly acidic condition; pH <1.0; UV-vis 630nm]
5. Chromotropic acid (2,4-Dichlorophenoxyacetic acid) (chromotropic acid in 75% sulfuric acid reacts with formaldehyde; peaking at 580nm wavelength).
6. Chromotropic acid + Bisulfite solution.
7. Chromotropic acid + 1% Sodium bisulfite solution.
8. J-acid (6-amino-1-napthol-3-sulphonic acid; 7-Amino-4-hydroxy-2-naphthalenesulfonic Acid; CAS No. 87-02-5; Sigma: 08800 FLUKA) (University of Cambridge; PhD Thesis: A new J-acid method for the detection of formaldehyde; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599295) .
9. Phenyl J-acid.
10. Mixture of dichlorosulfitomercurate (II) complex and acid bleached parasoaniline hydrochloride.
11. Formaldehyde + Mixture of dichlorosulfitomercurate (II) complex and acid bleached parasoaniline hydrochloride. (Schiff’s test?!)
12. 5,5-dimethyl 1,3-cyclohexanedione (Dimedone, Methone) (Sigma 38490 FLUKA).
13. 2-hydrazinobenzothiazole (along with 1% ferricyanide and 10% sodium hydroxide; deep blue colour in presence of formaldehyde) Sawicki and Hauser (1960).
14. 2-Hydroxycarbazole Reagent: Yellowish to Dark Blue colour
15. Nash/Hantzsch Reagent (2M ammonium acetate, 0.05M acetic acid, 0.02M acetylacetone): gives yellow colour; can be measured using spectrophotometer at 412nm
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I used ICP-OES for mineral analysis in food samples. i digested 1g sample in 8ml of triacid mixture and made up volume to 100ml with dist.water. I got the ICP-OES values in ppm. I used 50ml for analysis. How to calculate dilution factor for this? which is diultion factor for this? Whether 8 ml acid or whole 100ml ? Whether we can represent the results using arbitary mass unit (g/100g). Read many references and didnot got clarity about this. Kindly provide your valuable suggestions. 
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Is a simple, general "rule" or calculating method.
1. You give the sample weight in [g] (In your case 1 g)
2. You give the final volume (after digestion) in [ml] (In this case 100 ml)
Note: the volume of acid for digestion isn't important, and the volume used for analysis (50ml) also not important (if there was not a further dilution from 100 ml).
3. The calculating factor = volume / weight = 100 / 1 = 100 [ml/g]
4. Your final result in [mg/kg = ppm] in original (solid or not) food sample will be (for example the measured ICP-OES result was = 4.5 mg/l potassium)
ICP-OES result in [ppm = mg/l] * calculating factor
= 4.5 mg/l * 100 ml/g = 450 mg/kg !!!!
Because the calculating factor 100 ml/g = 100 l/kg !!!!
and mg/l * l/kg = mg/kg !!!!
Explanation: if you give the sample weight in kg and final volume in liter
(in this case 0.001 kg and 0.1 liter) the calculating factor will be
0.1 liter / 0.001 kg = 100 liter/kg (= the same number = 100 ml/g)
and your final result = 4.5 mg/l * 100 l/kg = 450 mg/kg.
To calculate the result for 100 g original food sample - divide that by 10.
(potassium content =) 45 mg per 100 g food.
If You understand this simple general rule (points 1.-4.), it can be an unforgettable automatic routine, and you never will make a mistake.
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Is anyone aware of a referenced method other than (PCR/electrophoresis/elisa ) to detect GMO in foods and feed?
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The difference between a GMO and a non-GMO is a specific piece of DNA and the protein it encodes. Therefore, any method to detect GMOs would typically rely on finding that specific DNA or protein. Methods will be product-specific, so other ways may be possible depending on the GMO trait. Are you looking for a specific GMO?
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Hello Everyone
Laktan 900 seems to be a very promising device for quick milk analysis in field. Its portable and cost effective.
Can anyone explain the working principle of this device?
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I tried to determine the protein concentration of protein isolates at 280nm but i was not getting any reasonable results despite the various dilutions. Is there any other method or procedures i can use without using any reagent? Thank you.
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The most straightforward psectrophotometric method for quantitating protein content in biological samples is the Bradford method ( ) which involves the binding of the dye Coomassie Brilliant Blue G-250 to protein that causes a shift in the absorption maximum of the dye from 465 to 595 nm. The increase in absorption at 595 nm is monitored and appropriate dilutions of BSA protein are used to prepare a calibration curve based on this external standard.
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Hey lovely community,
can anybody help me out here? A friend of mine is searching for some sources where the main methods for the determination of bacterial count in the field of cosmetics and food analysis are explained. Couldn´t find so far what she was searching for. Would be very happy for any help. 
Many thanks!
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Oh, thank you so much! Have a great day, Sir.
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What is the most frequently used formula to determine sample size for analysis of food. Given scenarios are with known and unknown population size?
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I agree with Govinda Prasad Dhungana.
The food sample depends on type sample.
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Can I do crude fibre estimation of a defatted sample which I have dried at 105 degrees C after defatting it?
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Then simple answer is, yes.  Crude fiber does recommend defatting of the sample before analysis.  With your pre-drying step you will determine crude fiber on a dry matter basis.  Take a look at the analytical procedure found at: https://www.ankom.com/sites/default/files/document-files/Method_1_Crude_Fiber_A2000.pdf
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I'm trying to understand what laboratories in UK or any part of the world can offer in regards to biological monitoring of agents/pollutants specific to the food and beverage industry such as grain and flour dust, aerosol proteins, polycyclic aromatic hydrocarbons (PAH) , chlorine and hypochlorite used in cleaning and sanitizing, ammonia and sulphur dioxide used in refrigeration...etc 
I'm looking for articles, laboratories contacts, researcher profiles, that can help me to answer the question. 
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Hello Yehia,
Please see UK food chemical surveillance programme  which is coordinated by Food Authenticity Steering Group 
the chapter 4 of this book also would be helpful
Food Contaminants: Sources and Surveillance
I hope this will help
Amin
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The medicinal value of spices is as a result of their phytochemical content. Hence, there is need to evaluate the phytochemical constituent of the spices using the most suitable method.
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There will not be much difference, only volatile compounds will be effected. 
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It is usually essential making artificial samples by blank matrix with standard substance added in method validation. When it comes to the situation that target analyte as endogenous substance always occurs in the matrix, for instance, the citrate in oranges, it is almost impossible to get the real blank. Is there any  solution either alternative validation experiment design or alternative blank? Standards or codexes adopted strategies  are best.
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As Tim says, modifying representative samples to remove the endogenous metabolite can have limitations.
The method of standard additions does not solve the problem either because the question, rephrased, concerns primarily the specificity, and not matrix effects on the response.  We need first to establish whether the analyical response without standard addition is due entirely to the analyte citrate. Standard additions deals only with the question of whether the analytical response or working range is affected by the matrix. This situation commonly arises with LC-MS-MS methods of impeccable specificity, whenever a stable-isotopically labelled internal standard is not available.
The "perfect" solution is to dispose of a reference method for which we can be sure of the the specificity; for a major metabolite like citrate, single-column GC-MS should easily meet this requirement. Given the separating power GC columns, a non specific detector like FID may be judged sufficient. Possibly, suitable reference data for your analytical situation may already exist in the literature.
Many laboratories don't have access to expensive facilities. The best you can do may be to compare results using more than one analytical method, for example two kinds of liquid chromatography (which for the present problem can be found in manufacturers' catalogues). The decision on how far to take such development work is often dependent on economic factors, and it can sometimes be legitimate to give results as "citrate by such-and-such a method" in order to indicate to the client that there is a small risk of uncertainty due to lack of specificity.
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As per FSSAI / CODEX phosphoric acid (as P2O5) content in cocoa powder is maximum  2.5g / Kg
in my reach i am getting beyond the limit 1. alkalized(KOH) dark cocoa powder(ph :5.2 to 6.3) results are 16.80 g/kg,(method for detection IS: 14828:2000)
2. alkalized (sodium carbonate)cocoa powder (ph: 6.5 to 7) phosphoric acid result 19.78 g/ kg(Method for detection IS 14828: 2000)
3. Natural cocoa powder (without alkalization) phosphoric acid result 5.22g/100g (UV method for detecting phosphorus then converted to phosphoric acid by molecular weight )
As per FSSAI  & CODEX standards 3 samples getting phosphoric acid  result above the limit 
can you share the possibilities of  presence of the phosphoric acid  in cocoa powder 
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There should not be any mistake in your procedure (if you are strictly following IS 14828 : 2000). You may do a confirmatory test by using the AOAC or APHA method (it is available free on the internet). In the mean time I would be very thankful to you if you could send me a scanned copy of the IS 14828 to my email address: ghoshjai@gmail.com
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The method which relevant to analysis of above mention sweeteners by using HPLC-UV/DVD
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Hi,
I have samples of food waste,  consist of rice and chicken meat waste, . I want to digest the samples to analysis crud protein. Also, I ash some samples before I digest to analyize Ca and P. For cude protein samples,the problems are the samples can not digest completely in spite of I use one tablet, H2O2 and H2so4. the temperture for first hour is 220 C and for the second hour is 410 C.The samples become milky color and still like this even I keep them in digester for 4 to 5 hours. Also, after I ash some samples to Ca and P analysis. The samples  are still black color after I have digested for 10 hours in spit of it should be less than 30 minutes 
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ok, I will decrease the weight but may I know can determine the crude protein by NC Soil Analyzer. the mechine for determine nitrogen without digestion. Normally, it use for determine the nitrogin in the soil. Can I determine the nitrogin in tissue samples by this mechine? 
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Primarily the usage of XLD agar is for the detection of Salmonella species in food analysis. Some sources say that e.coli also can be detected by the presence of yellow colonies. Theoretically yellow colonies observed for the presence of other Enterobacteria which maybe also coliforms. Any suggestion for the testing methods  to justify this yellow colonies? Thank you. 
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Hi Ugenthira,
I will advice that you should try and follow the right protocols for the isolations of Salmonella and E. coli. The protocol for Salmonella includes an initial pre-enrichment in buffered peptone water (which is the same for E. coli too). However selective enrichment for salmonella differs from E.coli. Salmonella; selective enrichment is done using modified semi-solid rapparport vassiliadis agar or some people use rapparport vassiliadis broth, then you can culture on XLD, or Brilliant green (BGA) agar, then you purified using nutrient agar. Then you can store the isolates at -80 degree celcius in brucella-broth for further analysis.
For selective isolation of E.coli, from the buffer peptone water pre-enrichment, you have to carry out selective enrichment in EC broth ,then culture on either MacConkey or  EMB agar. Then you purified either blood agar or nutrient agar.
I will advise you keep the two protocols separate if you are interested in both E.coli and Salmonella. Cheers
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see above
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I would like to determine hemagglutination activity in legumes.
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Simply, take 2% erythrocyte with 98% PBS.
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In paper or techniques manual, 7.8 value is taken for calculation of TBARS (mg malonaldehdyde/kg sample). But no one is mentioned how this 7.8 value is considered for calculation. Can anyone enlighten me it properly? 
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Do you find any solution for this question? 
I'm stuck with the same question as well.
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Hello everyone,
I am stuck on this question since last 2 days.. thought to share with you guys.. 
i want to know that what do you exactly mean by diet studies and if someone is planning to do it for a specific set of products then how it should be calculated..??
If you can provide me any relevant publications then it will be great help..
Thank You 
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We are completing an experimental study where macronutrients have the same percentages, but pellets differ for the quality of nitrogen provided. We are exploring how EAA/Non EAA ratios (Essential Amino Acids) may influence lifespan. The more % NEAA  contained into pellets, the shortest is lifespan. EAA only containing pellets near doubles lifespan observed by control laboratory diets. Covariance is quite linear. Epigenetic modifications are  very different according to organs examined, and what found in liver, as an example, cannot be translated to what happens in muscles.  Adipose tissues modifications are prominent, and independent by dimensions of spontaneous food intake.
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I need full procedure methods of AOAC for yoghurt Analysis can any body help me?
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Please see the attachment......
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I try to quantify paraquat/diquat in potato using LC/MS similar to the attached method but using different LC column. I use standard in solvent with internal standard (IS) to correct for matrix effect (paraquat has enhancement). The issue is the response of the analytes and IS is not consistent in sample matrix so the number is way off (sometimes is too low, sometimes is too high). I injected the same blank matrix with analytes 5 times and response was not the same. The run is isocratic so the matrix of the first injection may show up in the second or even the third injection. The paper use matrix-matched standard with IS (which is over kill) and it may be necessary to do it. I e-mailed the authors but so far no response. any comments are welcome.
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@Heydebreck  I will check on this but the final decision for what I remember, you have to spike at just before extraction because at the low level, I found that the matrix will absorb a finite amount of analyte and it will be corrected by adding standard at the beginning. Most of the time, I prefer to add IS just before analysis to correct for only matrix suppression and save money. Most of the method on internet (even QuPPe) prefer to add at just before extraction.  By adding IS just before extraction will disguise the poor extraction method and if you have poor recovery, you need to fix it and not using IS to compensate.
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food chemistry 
fraying potato
degredation of acrylamide  
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Hi
you can used HPLC method
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Please advise me the standard methods to estimate the shrimp allergen and also to identify the associated protein of shrimp allergen.
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Hi Md:
Not only tropomyosin, but also parvalbumins and other proteins can cause allergy. In this case it might be useful to detect crustacean DNA in a generic way, to infer the potential presence of these allergens in food.
I'm enclosing the abstract of a classic paper by a researcher from FDA:
Best regards
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I have to evaluate yoghurt samples for six characters (i.e. Color, Appearance, Odour, Taste, Texture and Overall acceptability) using a 5 point hedonic scale. Can I use 5 samples at a time?
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Hello,
Minimum 03 and maximum 05
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I am doing a research on Tofu and trying to increase the yield of tofu. When we did a test on frying firm tofu, tofu curds seemed to shrink not expand.
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The optimum yield obtained from optimum pH isoelectric, I think you can test it with the pH meter when coagulation process and like Mr. Zhang said, you can try more extraction method (traditional oriental is preferred because higher protein extracted). My research was about tofu too, I hope it's not too late
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ML for Ochratoxin A in milk
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Thanks all for valuable inputs.
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Dear researchers,
I want to add alpha-tocopherol to chitosan film forming solution to prepare chitosan film with alpha-tocopherol. First I added tween 80 as an emulsifier to chitosan film-forming solution(2%) at concentrations of 50, 75 and 100 percent of alpha-tocopherol that then was added to chitosan film forming solution at different concentrations of 0.1, 0.125, 0.15 and 0.2 percent of the solution. Then, it was homogenized with ultra turax at 13000 and 27000 rpm and dried in petri dishes at oven( 30 D. of celsius). Unfortunately, all prepared films showed greasy surface and non-uniform structure. Can any researcher help me how can I prepare a better film with uniform structure? 
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That's right but I think the surface is nonuniform because the emulsion becomes unstable at drying step.
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I am looking for possible off-notes (aroma and flavours) that can be due to carbonation of drinks. I am studying which off-notes can appear due to carbonation or can be attribute to the CO2 in carbonated drink. Any case-study is welcome.
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I agree, if a food treated with carbon dioxide has a flavor off and flavor derived from the deterioration of the food and can not because of CO2. In so red wine is excessive CO2 Known pour augmenter Perceived bitterness of the tannins.
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Hello.. I am identifying peptides from buffalo casein by ESI-LC-MS/MS. Mascot 2.5 software identified peptides by matching the amino acid sequences to cow or bovine source. It is showing sequences of peptides derived from cow casein. Rather there is high homology between amino acid sequences of buffalo and cow casein. But if i want to know the replacements of amino acids in identified peptides of buffalo casein then what approach i can do to solve this problem.
Thanks in Advance
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Have you tried the ExPasy website; there are all manner of BLAST tools for comparing sequences. Regards.
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I used the kit and I found values really low of glucose and fructose, while sucrose was really high. Normally in grape berries we should find more than 100 mg/g of glucose and fructose and less than 1 mg/g of sucrose.
Did you have the same result?
If yes do you have any explanation for that?
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My best explanation is that it might be a calculation error, as you need to subtract the total glucose value (after hydrolysis) from the initial glucose value in order to calculate the sucrose concentration. This may explain the high values for sucrose in relation to the glucose/fructose values. As you did have results for the sucrose, it is unlikely that something was wrong with the kit.
I unfortunately only used these kits to evaluate the content of the remainder of the vine organs, and use the HPLC and enzymatic robot for grape berry analyses. Your expected concentrations are correct though, if you are looking at the concentrations in berries at harvest.
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I would like to determine WAI and WSI but i recognised that there are different formulas for them in some articles.
For example, while formula of WAI is explained  
WAI% =((Weight of centrifuge tube and sample - Centrifuge tube) / Weight of sample )* 100 in one article (principle= 2.5 g of sample in a poyethylene tube. 30 mL of distilled water were added and stirred with sample, water bath with 25 C for 20 min. centrifuged at 5000 rpm for 10 min.
The water was then decanted from the tube without loss of solids.
Finally, the tube and residues were weighed out and calculated)
the other is explained WAI = weight of sediment / weight of dry solids (principle=Each sample
(1 g) sample in 6ml of distilled water and stirred for 30 min at 30 C temperature.The dispersions were centrifuged at 4000 g for 20 min using The supernatants were poured into dry test tubes and stored overnight at 110 C for the process of evaporation. 
Fırst equation sounds wrong. Maybe i think wrongly. Could u explain ?
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Thank you for your attention and explanations. 
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Is anyone aware of the % contribution of snacking to total daily energy intake in the UK? I have visited nationally representative survey data to no avail, and consequently struggling to find any literature that may offer suggestion. 
Thanks.
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