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Food Chemistry - Science topic

Food Chemistry are composition and impurities in foods
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Our primary experiment results indicated that food resource arabinogalactan protein (AGP) could combine with phenolic compounds, such as epigallocatechin gallate (EGCG), thus can mask bitter or astrigent taste and function as a good carrier of these bioactive components in food processing. As a kind of proteoglycan, we are planning to modify its sugar moiety and to test whether the sugar moiety take key function in combination with EGCG. Does anyone have experience in the enzymatic treatment of AGP or proteoglycan based on sugar chains?
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I'm currently looking at the rheological properties of the polymer Xanthan Gum. focusing on its dynamic viscosity to be more specific. I'm assessing the effects of pH (ranging from 3.6 to 5.6, 0.4 increment, total of 6 pH's) on the dynamic viscosity of xanthan gum solution (dissolving xanthan gum powder into acetic buffer with equal ionic strength, concentration is kept at 0.04%).
Firstly, my viscosity data collected shows that, as pH increases from 3.6 to 4.0 then 4.4, the viscosity increases; but as I bring up the pH from 4.4 to 4.8, 4.8 to 5.2, then lastly 5.2 to 5.6, the increasing viscosity trend plateaus and the increase in viscosity is less significant compared to the 3.6-4.4 jump. At this range, does pH has an effect on the viscosity of xanthan gum based on its molecular configuration? Though some sources states that xanthan gum's viscosity remains stable and unchanged within the range of pH 3-12 at a high concentration like 1% not 0.04%, yet some suggest pH still plays an effect, though I'm not sure how on the chemical and molecular aspect.
A possible conjecture I can think of is the xanthan gum's order-disorder and helix-coil transition is affected by protonation. In figure 2, it demonstrates how electrolytes affect the structure of the polymer; in figure 3, it shows how at a state of a helical rod and no longer a random coil, it is capable to hydrogen bonds among each other. Hence, I'm wondering of pH plays an effect on it's structural transition, such that the increased intermolecular forces at the form of a helical rod would make it more viscous in solution.
Here are the resources I have used so far:
Brunchi, CE., Bercea, M., Morariu, S. et al. Some properties of xanthan gum in aqueous solutions: effect of temperature and pH. J Polym Res 23, 123 (2016). https://doi.org/10.1007/s10965-016-1015-4
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Dear Ryan Lo, you may find various stufies on this topic. Please have a look at the following free access RG fille. My Regards
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Hi there!
I work with infrared spectroscopy (NIR & FTIR) in the field of food science/food chemistry. I'm looking for collaborators with experience in chemometrics (particularly PLS-R & PLS-DA, but other discriminant methods such as SVM or neural networks would also be great). In particular, I'm after people who would be interested in helping with data analysis & writing up some papers based on data I have collected.
If you are interested & have such experience, please contact me & I would love to discuss with you.
Joel
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you can contact me and Dr Silvio David Rodriguez for possible collaborations.
Regards,
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Dear to whom it may concern,
I wonder whether benzopyrylium ion is permanently or temporarily positively charged because I would like to convert its positive charge to its neutral form.
Would you mind if you may give me some suggestions in this case?
Best regards,
Khoa.
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If you do that, you can destroy the ring system or by reaching a ring opening, get benzopyran or a substitution
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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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I want to know the recommendation of energy contribution by meal in school children (9-11 years old).
I have been reading that it is aprox 20-25% for breakfast, 25-30% for lunch, 20-25% for dinner and 15-20% for snacks, but I can not find a good source of information.
Thank you for your help. 
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I'll be conducting my thesis in Japan soon and I want to know what is the best method to personally bring viable microorganisms (specifically Lactobacillus spp.) in-flight.
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I recommend
Girish Korekar
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best wishes
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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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Milk-loving people, let’s discuss this video! I'm for sustainable agriculture and I agree that Remilk is revolutionary but there were points in this video that got me thinking:
1. “Milk is not healthy” is a broad presumption. Sure, there have been researches that were for and against consuming milk. But I consider milk as a healthy food since it contains proper amounts of dietary fats, proteins, vitamins, and minerals needed by the body. It is a reason why dietary guidelines (such as issued by the United States Department of Agriculture) recommends consuming three daily servings of low-fat/non-fat milk, yogurt, or cheese.
2. Alright, milk may be bad for consumers who can’t tolerate lactose. But how about in fermented milk products? During fermentation, microorganisms utilize lactose and produce lactic acid. I can think a lot about how lactic acid production is important in fermented milk products.
3. Milk has cholesterol but a cup of whole milk only contains 0.01% of cholesterol. How much more in low-fat or non-fat milk? Also, milk consumption increases HDL (high-density lipoproteins) cholesterol which transports excess cholesterol from the bloodstream to the liver for bile production. Bile serves as an emulsifier in the digestion of dietary lipids.
4. Indeed, milk is predominantly comprised of saturated fats. However, these saturated fats can be converted to unsaturated fats by microorganisms (e.g. lactic acid bacteria) during fermentation.
5. I can agree that milk is not entirely sustainable in the sense that the dairy industry greatly contributes to greenhouse gas (GHG) emissions compared to other agricultural practices. But we can’t ignore that there has been a significant reduction in GHG emissions throughout the years primarily by changes in breeding, nutrition, and management practices.
6. I honestly don’t know what to feel about animal abuse in the dairy industry. Does continually breeding dairy animals and leaving them in a lifelong cycle of reproduction and lactation might be considered animal abuse? (In my mind, it's a sad yes.)
7. Let’s say that the microbes have the same machinery as the cow’s mammary epithelial cells in producing milk, is it certain that they will have the same physicochemical composition, property, and functionality?
8. What are the external nutrient sources of the microbes? Is it the same nutrients found in the cow’s blood?
9. It is contradicting that they want to produce milk from microbes with the same chemical composition as cow’s milk but with no lactose?
This video discussed valid points that can be considered problems in the dairy industry. As long as this microbially-produced milk does not sacrifice the wonders of milk; Remilk, why not?
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I agree with you why not.
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Phenolic quantification with a absolute precision MALDI-TOF is performed. Is there any database exist by which we can compare our ms/ms data? I am already aware about the phenol explorer. But I think it is a new and many undates will be needed to make it more accurate.
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agree with Rana Mustafa
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Which molecular properties cause oil rancidification other than unsaturated C-C bond? Does ester bond braking rancidification continue without moisture?
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Interesting question
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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'm going to find the substitution for microencapsulating materal, eg:alginate and popl.
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At both very high and very low water activities, lipid oxidation rates are high compared to the rate at intermediate water activities. What can explain this trend?
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The relationship between rates of lipid oxidation and moisture is complex. The amount of water, the water activity and the state of water in a food, along with other factors, must all be considered.
For most fresh or tissue foods that have moisture contents between 60 - 95% have a water activity very close to 1.T he mode of deterioration at this water activity is generally microbial or enzymatic in nature. Direct lipid oxidation (i.e. not enzyme-mediated) is not an important source of deterioration at this high water activity since other modes of degradation will deteriorate the food first.
Concentration, freezing, and drying are mechanisms by which the water activity of food can be reduced. Such processes may bring the food into the intermediate moisture or low-moisture region where direct lipid oxidation becomes a more important mode of degradation. Also, during dehydration, free radicals can be formed which accelerates lipid oxidation. Freezing can also lead to the acceleration of lipid oxidation rates through the concentration of substrates and catalysts in the unfrozen portion of the system.
On the other hand, Chou et al. (1973) found that water activity primarily affects matrix swelling and thus substrate/reaction site availability as well as catalyst mobility.
Hereinbelow the tow common theories related to the relationship between water activity/content and lipid oxidation are briefly discussed:
Monolayer theory
Unlike most aqueous chemical reactions, the rate of lipid oxidation that takes place in the oil phase is observed to increase as water activity is decreased below the monolayer (i.e. water molecules that are bound tightly to the food surface). This can be explained by considering the role of water in this reaction. It has been suggested that the monolayer of water—or rather, the water saturation of polar groups in lipids—is necessary to cover the surface of the lipid, preventing it from direct exposure to air. This monolayer is essentially “bound” water with limited mobility and is assumed to not participate in chemical reactions. Several studies have found that a variety of foods are most stable to lipid oxidation at a relative humidity or aw consistent with the monolayer.
On the other hand, water can form a hydration sphere around metal catalysts such as Cu, Fe, Co, and Cd. In the dry state, the metal catalysts are most active. As water activity increases, the metals may hydrate which may reduce their catalytic action thus slowing the rate of lipid oxidation.
This monolayer theory, however, cannot be applied universally.
Glass transition theory
According to the glass transition theory, one important function of water is its ability to act as a plasticizing agent. The plasticization of a matrix involves swelling of the polymer matrix when moisture is increased. The resulting increase in free volume might allow for faster diffusion of substrates in the aqueous phase which may lead to faster reaction rates. Plasticization may also increase the contact of the absorbed aqueous phase with the lipid phase. The number of catalytic sites increases such that the rate of lipid oxidation increases.
The above discussion shows that water plays both protective and prooxidative roles in lipid oxidation. In some foods at low aw near the monolayer moisture content, water is protective, presumably because it provides a barrier between the lipid and oxygen.
While the classic food stability map proposed by Labuza et al. (1972) shows lipid oxidation having a U-shaped relationship to aw, no U-shape was also observed; lipid oxidation actually slowed as aw increased as the case of freeze-dried food.
Overall, monolayer and glass transition concepts might not effectively predict lipid oxidation reactions in some foods if oxidation is primarily occurring in the lipid phase and thus would not be significantly impacted by water and the physical state of proteins and carbohydrates. On the other hand, water can play a major role in lipid oxidation chemistry if reactions are primarily promoted by water-soluble prooxidants such as metals. Unfortunately, the causes of lipid oxidation in low-moisture foods are poorly understood, which could be why measurements of water activity, monolayers, and glass transitions do not consistently predict lipid oxidation kinetics.
Sources:
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The last few days i have determined reduced sugar content from grass that was both hydrolyzed with sulfuric acid as from grass extracted with distilled water. Because the calculated concentrations of both extractions did not differ from each other, i decided to do a test where i used maltose and fructose as a positive control and dextrose as the standards set. This test was intended to verify if the method used is valid. The determination of reducing sugars is performed using dinitrosalicyclic acid method. Is there a reference value for both fructose and maltose in the literature?
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Sugar Meal Composition of Five North Central Florida Mosquito Species (Diptera: Culicidae) as Determined by Gas Chromatography
  • July 1999
  • Journal of Medical Entomology 36(4):462-7
  • DOI: 10.1093/jmedent/36.4.462
  • D A Burkett
  • D L Kline
  • 📷David Arthur Carlson
  • This publication describes GC analysis of sugar meals in wild mosquitoes.
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I Have directed a doctorate thesis on trials of cultiva tion of Pelargonium graveolens in order tout optimize yields and a quality of chemical compounds of this plant extraits. I need scientific collaboration in chemical analysis and their application on cosmetic or food chemistry, the doctorant Can beneficied a short course. Please to purpose us a laboratory to complete study and prepar a scientific paper.
Thank you vert much.
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Thank you dear colleague.
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I am currently conducting a study about the formation of free EPA in raw oysters treated with acidic sauces. For separating the polar and nonpolar lipids, I will be using Sep-pak C18 catridges. However, I am still a student and buying a large amount of cartridges (50) is out of my budget. Can you recommend any alternatives for this method?
Any answer or literature will be much appreciated, thank you!
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Silicium (though you change the elution mechanism), or LH-20, which come in bulk so you can pour your own columns.
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I am currently proposing a study about the formation of free PUFAs (EPA and DHA) in raw oysters treated with acidic sauces. Based on a study by Sajiki et al. (1994), free PUFA formation may be caused by the activation of lipolytic enzyme in the oysters treated with acetic acid. However, I am confused regarding this mechanism since the oysters are not alive. Can this explanation be used for dead oysters? Is there a better explanation for the formation of free PUFAs?
Here is Sajiki's study if you are interested:
Any answer or literature will be appreciated, thank you!
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I agree with C.A. (Kees) Kan
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Has anyone has experience to extract gelatin from jelly fish and yield of gelatin?
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Hi I'm Dr Mariem Kharroubi from Morocco
In your researches , Did you use whole body as rawmaterial to extract gelatin or just umbrella
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At above-freezing temperatures, I know RVP is a function of temperature and food composition. However, it becomes dependent on temperature when its sub-freezing temperatures and the kind and ratio of solute no longer matters. How is this related to the water activity? Is it because the water freezes and the ions of the dissolved solute no longer disrupt the structure since they're immobilized as well?
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Dear Alexandra
1- The initial freezing point of food was estimated from the mole fractions of individual solutes in the aqueous phase such as ions, sugars, acids and alcohol.
2- Moreover, every kind of foodstuff had on your own component that is different with another varieties.
3- foods are full of Vitamins, minsrals, soluble and insoluble fiber withe diffrent vapor and freezing point temperature.
Every part of these component had specific freezing point.
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Does it have something to do with its ketone group or a different property? Please explain.
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Dear Alexxandra,
very good thinking. In aqueous solution, fructose is an open-chain to a small extent and is present predominantly as α- or β-fructopyranose, which partially merge by mutarotation. In crystalline form, fructose exists as a closed pyran ring (fructopyranose). The keto group which is only present in fructose's open chain form has now turned into an OH- group by nucleophilic substitution during ring formation. Therefore, the keto group doesn't play any role in incorporating water into fructose's crystalline structure. Crystals of fructose exist as either anhydrous β-d-fructopyranose or as the dihydrate or hemihydrate (one molecule of water of crystallization per two molecules) of β-d-fructopyranose. Dihydrate fructose crystals can dissolve in their own water of hydration and must therefore be handled very careful. By the way, the water of crystallisation is not chemically bound, but only weakly bound by hydrogen bonds (electrostatic forces) and may normally be removed by heating.
Wishing you best of success,
Johannes
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I want to use FAA solution for temporarily preserving banana leaf sheath. Can anyone tell me the exact composition of the FAA solution and also whether there is any possibility of damaging tissues to be preserved? 
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Dear Nikita,
There is no exact composition for FAA.
Actually, there are various recipes for FAA. If your samples are the type that become harden easily, so reduce the concentration of the alcohol and formalin.
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Nothing can be harmful if used in moderation.
Milk and other dairy products are the top source of saturated fat in the diet, contributing to heart disease, type 2 diabetes, and Alzheimer's disease. Studies have also linked dairy to an increased risk of breast, ovarian, and prostate cancer.
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Best drying temperature for pasta.
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Dear scholars,
In order to modeling the bread staling, Avrami Model (please check the attachment) has been used in papers. Some of its part are unclear for me:
θ(t) is the fraction of recrystallization
F0, Ft, and F∞ are the firmness values at zero time, t time, and infinite time, respectively
k is the constant rate of the process; and n is the Avrami exponent related to the crystal morphology that describes the order of crystal
growth
n is Avrami exponent
I don't understand how "k" and "n" can be measured?
I appreciate your guidance.
Regards,
Amir
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Hello Amir!
As long as I know, you don't measure "k" and "n". These will be the parameters that describe the shape of your fitted curve when you use Avrami equation for modeling your "F0" and "Ft" data.
The input values for Avrami modeling should be F0 and Ft, while the output parameters should be F∞, k and n.
Since θ(t) = (F∞ - Ft)/(F∞ - F0), you may have to transform your equation or normalize your data if you have no idea of the F∞ value. If you have a clue of the value of F∞ you can use it as a initializing value of the iteration.
I hope you find my answer helpful.
Regards,
Gabriel.
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I want to publish my paper. So I want to know some recognized conference.
Areas focused : food chemistry / bioactive compounds/nutrition
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Min Yap Thank you very much for the answer. I have already found about afc 2019 but I couldn't find any information about its index/ranking. Do you know about it?
I'll search about icnfs since I didn't know about it.
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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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I need the values to explain the wetability properties.
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I think you shlohd do Atomic Force Microscopy technique.
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It is well known that Strawberry leaves contain high amounts of diverse phenolic compounds (Kårlund et al. 2014), and also polyphenolic compounds are known to interact with proteins and can inhibit enzymatic activity (Dawra et al. 1988; Suryanarayana et al. 2004).
How can I avoid high levels of polyphenols in strawberry leaf extracts? These high levels of polyphenols interfere with enzymatic activity.
What kind of techniques or protocols do you use to purify raw strawberry leaf extracts and eliminate polyphenols?
Thank you very much!
JD
Dawra, R. K., Makkar, H. P., & Singh, B. (1988). Protein-binding capacity of microquantities of tannins. Analytical Biochemistry, 170(1), 50–53.
Kårlund, A., Salminen, J. P., Koskinen, P., Ahern, J. R., Karonen, M., Tiilikkala, K., & Karjalainen, R. O. (2014). Polyphenols in strawberry (Fragaria× ananassa) leaves induced by plant activators. Journal of agricultural and food chemistry, 62(20), 4592-4600.
Suryanarayana, P., Kumar, P. A., Saraswat, M., Petrash, J. M., & Reddy, G. B. (2004). Inhibition of aldose reductase by tannoid principles of Emblica officinalis: Implications for the prevention of sugar cataract. Molecular Vision, 10, 148–154.
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Yes SPE on N-vinylpyrrolidone-divinylbenzene copolymer would also work nicely, and you can find commercially prepacked cartirdges.
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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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Though high H+ strength can reshape tannin structure thus makes it more reactive to saliva protein, who actually reacts first with saliva protein?
Is there a threshold/balance point that determines whose binding effect is dominant?
Or is there a model demonstrating the synergistic effect from tannin (when acid-astringency is dominant) or from acid (when tannin-astringency is dominant)?
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tanin
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I want to ask about how to calculate the total carotenoids in an extract using the spectrophotometer.
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Yes, you have to make a calibration curve with beta carotene, but if you don' t have any carotene, you can use potassium dichromate, there is a method. Or you can calculate directly the concentration of carotene using the molar absorption coefficient, but it is not the best choice.
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How can I prepare a stable solution containing chitosan-caseinate sodium complex without precipitation?
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Chitosan, a cationic polysaccharide, was heterogeneously deacetylated with a 47% sodium hydroxide solution and followed by a homogeneous reacetylation with acetic anhydrides to control the N-acetyl content of the chitosan having a similar molecular weight. The chitosans having different degrees of N-acetylation were complexed with sodium alginate, an anionic polysaccharide, and the formation behavior of polyelectrolyte complexes (PECs) was examined by the viscometry in various pH ranges. The maximum mixing ratio (Rmax) increased with a decrease in the degree of N-acetylation of the chitosan at the same pH, and with a decrease in pH at the same degree of N-acetylation.
The chitosan-caseinate complexes formed were stable and soluble in the pH range 4.8-6.0. In this pH range, the biopolymers had opposite charges. At higher concentrations of chitosan (0.15 wt%), the soluble complexes associated to form larger particles. DLS data showed that, between pH 4.8 and 6.0, the particles formed by the complexation of chitosan and caseinate had sizes between 250 and 350 nm and these nanoparticles were visualized using negative staining TEM. Above pH 6.0, the nanoparticles associated to form larger particles, causing phase separation. Addition of NaCl increased the particle size. The pH dependence of the zeta potential of the mixture solutions was appreciably different from that of the pure protein and pure chitosan solutions.
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I like to document the elements present in my fruit sample. Came to know about this EDX spectroscopy and hope it will serve my purpose. My question is whether a single run itself will give a spectrum with all elements which are present in the sample? And how estimation of each elements is done?
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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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Recently, the isolation of protein from protein-rich plants using various isolation methods has increased tremendously to meet the protein requirement of people, enhance the utilization of such plants and sometimes as functional food ingredients.
However, the protein contents of protein isolates obtained via various methods such as micellization and isoelectric precipitation from the same sample are expected to be closed with micellized protein isolate probably having the highest protein content. What could then possibly caused a significant difference between the protein contents of micellized and isoelectric precipitated protein isolates of a sample with micellized protein isolate having lower protein content?
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By micellization, isolating proteins is easier. All proteins in the presence of available electrolytes are folded into micelles, and then removed by centrifugation, ultrafiltration. Рroteins are separated by an isoelectric point (pH); each protein has its own isoelectric point when it is not charged. To create pH, it is necessary to prepare a buffer solution of a composition of certain salts.
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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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This is still for my thesis on breadfruit chips
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pH will not have a significant change on proximate composition but soluble solids would affect the same.
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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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ammonia
urine
food
cat food
pet food
chemistry
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The answer in the attached link gives tips to decrease ammonia level in human blood & advises the use of herbal tea plus lemon or grapefruit seeds.
I think that drinking plenty of water is a better remedy for many diseases including this one.
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I recognised that there are fluctuation about protein contents of functional bakery products in literature. I try to understand it based on food chemistry. For example; %0, %25, 75, 100 quinoa is replaced with wheat flour in cake or bread production. Protein contents of products fluctuated %8, %7, %7, %9 protein. Why this fluctuation happens? 
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Dear Elif
Your answers do lead me to new comments/questions
  1. How did you exchange wheat and quinoa, or a weight or on a protein basis? This might influence results also
  2. My main concern is the size of the primary sample. If the material is (quite) coarse, it is (almost) impossible to obtain two 25 mg samples that are identical in composition. The standard procedure in feed analysis is always to mill the product to a (fine) powder, then mix this powder thoroughly and take (rather large) separate samples and start your work with them as the primary samples. Thus with totally independent samples right from the start. Then you can duplicate analyses on these independent samples
  3. The conversion factor is not my worry, but the repeatability of your measurements. Thus measuring several samples of the same analytical solution and calculating the standard deviation in those results. But also calculating the standard deviation of measurements on (in principle) identical samples. This might be quite low for aqueous solutions but considerably higher when dealing with biological material.
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Bamboo shoots caontain toxic substances which needs to be removed before consumption. I learn from my collegues people are following soaking principle to dissolve these harmful compounds. If you know anything about it, please let me know.
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toxins in food products in general, are reduced significantly by soaking in fresh water. the water however needs to be changed and replaced with fresh one quite frequently (about 6 hours interval) for 48 hours.
Boiling is another means of detoxifying, but i haven't personally tried it.
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What is the indicated methodology to perform sedimentation, viscosity and turbidity test for fruit juices ?
 
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Hello Dear,
You can see the following Links. I hope it helps you.
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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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At the moment I have structured data set of profiles of exporters and  pasts results of each tea sample that were tested in the laboratory.  In this process there are 6 main reasons which could lead to reject a sample during the inspection. They are as follows. 
·         Microbial contamination
·         Contamination  due to adulteration (add : FeSo4, NaCo3, sugar,CaCo3 )
·         ISO 3700 Limits (Crude fiber > 16.5% )
·         Silicon Acid insolubility (1%)
·         Fake grade
·         Full analysis
o   Alkaline test
o   Water Extraction
o   Total poly phenols (Anti-oxidant)
Are there any similar researches conducted which could help me to refer as literature for above research?.
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Not at all
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Thermal and non-thermal food processing
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in addition to the aforementioned methods you can also use AOAC, herein attached, https://www.edgeanalytical.com/wp-content/uploads/Food_AOAC-989.05.pdf
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Dear All
Here I attached my antioxidant result for your perusal. Result for IC50 is 0.52 mg/ml. that is the amount of antioxidant necessary to decrease by 50% the initial DPPH concentration. May I know 0.52mg/ml is refer to the antioxidant activity contained in dragon fruit peel dried or in extraction solution of dragon fruit peel? concentration sample is 0.2 to 1 mg/ml. I dissolved 2 mg powder of dragon fruit peel dried into 10ml ethanol (70%) and followed with another concentration with the same step. The problem is dragon fruit peel dried powder is not fully dissolve into the solvent, So I just discard the sediment and take the solution for analysis
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Truly, I will recommend conducting the analysis again; and timing the extraction of your freeze-dried Dragon fruit powder.
A paper was published and it reported that extraction was done on the leaves of a plant, Perilla pankinensis for 2 hours. (Reference: Gulcin et al., 2005. Antiradical and antioxidant activity of total anthocyanins from Perilla pankinensis decne. Journal of Ethnopharmacology 101: 287 – 293). 
Another research study was conducted on the powdered plant, Black Cohosh for 12 hours. (Reference: Nuntanakorn et al., 2006. Polyphenolic Constituents of Actaea racemosa. Journal of Natural Products 69: 314 - 318.). The URL is:     http://pubs.acs.org/doi/pdf/10.1021/np0501031
Since Gulcin and co-researchers (above) cited doing a 2-hour extraction in a solvent with continuous stirring; it is advisible to time the extraction of your freeze-dried, Dragon fruit peel powder, by using any good publication you find as a guide.
I will also like to add that ensuring the purity of your solvent is important. You can do this by preparing your 70 % Ethanol accurately by adding 30 mL of distilled water to a 100 mL standard volumetric flask; and making up the volume to the meniscus mark on the standard flask with absolute ethanol, or 300 mL of distilled water to a 1L (1000 mL) standard volumetric flask and making up to the meniscus mark with absolute ethanol.  Alternatively, if you use redistilled solvents, ensure the ethanol supplied to you is distilled and measure the density to have any value in the range (0.7893 - 0.81 g/mL - Ref: Chemspider.com); before you prepare he 70% Ethanol.
I wish you all the best!
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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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There are lots of literature datas for antioxidant rich products. But i have a question there are any limits to be able to call a food as a antioxidant rich product. When i compare fruits and other related antioxidant rich materials with flour substituted functional food products, antioxidant level decrease significantly after processing.
Functional food products have more antioxidant activity than control food samples. However, is it enough to say it is a rich antioxidant food product ? 
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Hello Elif. I think your question is about when you can declare a food to be a "product rich in antioxidants" and if there are limits set to be able to make this statement.
I guess when talking about limits, you mean limits established in the legislation to make this statement, in specific foods that are marketed to the final consumer.
As I see you belong to a university in Turkey, I have to say that I do not know Turkish legislation, since I am Spanish, but I can tell you what the European Union legislation says about nutritional and health claims in food.
Specifically in the European Union, nutritional and health claims must be authorized by the European Commission to be used in the labeling or advertising of food. This authorization is based on the reports of the European Food Safety Authority (EFSA). The EFSA bases its reports on scientific evaluations of health claims applications. In many cases of requests for health claims, EFSA has issued negative reports based on the fact that such requests do not establish, through appropriate scientific studies, a causal relationship between the consumption of those foods and the requested health claim (in many cases this is because No human intervention studies are presented, from which conclusions can be drawn for the scientific basis of the healthy declaration by the applicant).
This is the case for all claims for health claims on foods or nutrients with antioxidant properties that have been submitted for authorization in the European Union. So that at present there is still not a single health statement authorized on antioxidant properties of any food throughout the European Union and therefore no declaration can be made on antioxidant properties in the labeling, presentation or advertising of any food that is Commercialize in it.
Nor is there any authoritative nutrition statement that uses the word "antioxidant" in your wording, as you might say: "antioxidant rich product".
If there are nutritional claims of the type HIGH [NAME OF VITAMINS] AND / OR [NAME OF MINERALS], for example the nutritional declaration "High Vitamin C" that can be used if the food has a minimum content of 30 % Of the Reference Value of Nutrients, which in this specific case is 24 mg per 100g or 100ml of food.
I send you an Internet address where you can find all the nutritional and health claims authorized in the European Union: http://ec.europa.eu/food/safety/labelling_nutrition/claims/register/public/?event=register.home
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Hi, I want to conduct an accelerated shelf life testing of packaged coconut water. What can be the possible acceleration factor for the same.
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Can Q10 really be used as a stander shelf life evaluating method in Food Industry ?
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The method which relevant to analysis of above mention sweeteners by using HPLC-UV/DVD
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i'm searching a method for determine Protease activity in cereal, anyone can help me?
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This paper may be useful for you
Good luck
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frozen beef meat
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Firstly, confirm your suspicion for the presence of added carbohydrates by the simple iodine test, before attempting to quantify it. This is a potential minefield.
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Kindly provide simple extraction method which does not require any rotary evaporator. 
Thank you.
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my dear,i gree with Rohit Upadhyay
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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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Compliance with national standards regarding raw milk have recently been revised and the allowable bacterial limit in a raw milk sample have been lowered,  the traditional standard plate count (SPC) method on raw milk samples when compared with Bactoscan testing on the same samples are never in agreement and often the SPC count is higher than the Bactoscan result. Can anyone suggest why this is the case??
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Dear all
In Arla Foods we changed the way farmers are paid regarding bacterias i january this year, so that we use the IBC number (individual bacteria count) instead of CFU (coliny forming units), to make it fair and aligned for farmers across countries. The labs in each country have their own conversion factor to convert the bactoscan (IBC) to CFU, therefore the CFU number cannot be compaired across countries
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How to determine the carbohydrate content and calculate energy of meat without using bomb calorimeter. Is there any formula for it?
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Carbohydrate Counting 101
 
There are several different ways people with diabetes can manage their food intake to keep their blood glucose (sugar) within their target range and one such method is 'carbohydrate counting'. Carbohydrate, or carb counting is a method of calculating grams of carbohydrate consumed at meals and snacks. Foods that contain carb have the greatest effect on blood glucose compared to foods that contain protein or fat. Before starting any new treatment or meal plan, you should always consult with your diabetes care professional.
What are the benefits of counting carbs?
·   Counting carbohydrates is a good solution for many people with diabetes. Once you learn how to count carbs, you’ll find it easier to fit a wide variety of foods into your meal plan, including combination foods such as those in frozen dinners. For example, by checking the grams of total carbohydrate on the Nutrition Facts label  on a frozen dinner, you can figure out how to fit the dinner into your carb allotment for a particular meal.  Many people find carb counting to be much easier than using a more traditional exchange meal plan.
·   Another benefit of counting carbohydrates is that it can bring tighter control over your glucose readings. Being as precise as possible with your carb intake and medication will help you better manage your blood glucose after meals.  
·   Lastly, if you take mealtime insulin, counting carbohydrates allows you to decide how much carb you want to eat at a meal, rather than having to eat a certain amount of carbohydrates, even if you do not want to.
Who can use carbohydrate counting?
Carbohydrate counting can be used by anyone with diabetes, not just people taking insulin.
This method is also useful for people who are using more intensive methods of adjusting insulin to control diabetes. The amount of meal and snack carbohydrate is adjusted based on the pre-meal blood glucose reading. Depending on the reading, more or less carbohydrate may be eaten. Likewise, insulin may be adjusted based on what the person wants to eat. For example, if you want to eat a much larger meal than usual, carb counting can help you determine how much extra insulin to take.
The following is an explanation of how to use carbohydrate counting. Print these pages and discuss them with your nurse educator, dietitian or physician at your next visit.
Tools of the Trade
1.      The first step in carb counting is to have a meal plan.  A meal plan is a guide that helps you figure out how much carb, protein and fat to eat at meals and snacks each day.  If you don’t have a meal plan, meet with a registered dietitian.
2.      Step two involves learning which foods contain carbohydrate. Most people know that starchy foods, such as bread, pasta and cereal contain carbs.  But other food   groups, such as fruit, milk and desserts and sweets, have carbs, too.
There are three main ways to learn about carbs in foods:
o       Ask for a food choice list from your dietitian.
o       Learn how to read the Nutrition Facts Label
o       Purchase a food counts book that provides the number of grams of carb in various foods.
3.      Measuring tools.  In order to accurately count carbs, you’ll need to be accurate with the portion sizes of foods that you eat.  Invest in a food scale to weigh foods such as fruit and bread.  Use measuring cups to measure cereal, pasta and rice, and use liquid measuring cups for carb-containing beverages such as milk, juice and energy drinks.
Resources
Fortunately, there are many resources available to help you with carb counting  Below are a few to consider:
  ·   Staying Healthy with Diabetes:  Nutrition & Meal Planning (Joslin Diabetes Center)
·   Choose Your Foods:  Exchange Lists for Diabetes (American Diabetes Association)
·   Complete Guide to Carb Counting (American Diabetes Association)
·   The Calorie King Calorie Fat & Carbohydrate Counter (Alan Borushek)
·   The Diabetes Carbohydrate & Fat Gram Guide (Lea Ann Holzmeiste
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Any information whether any starch like potato or tapioca, which is usually added to processed fish can hinder the detection of fish allergen? Is there any specific reaction between allergen with the starch?
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The coating of feed ingredients with either starch of fat helps minimize nutrient losses during processing of the product. Therefore, if you are unable to detect any substance in an analysis, then it could possibly be a factor.
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I am trying to synthesized inulin ester with polycarboxylic acid such as ethylenediaminetetracetic acid and inulin using dimethylformamide as solvent. At the end of the reaction do l need to neutralize?
For the precipitation of the product- is diethyl ether, ethyl acetate, or acetone better?
For purification l have seen some journals using cationic exchange but l was thinking repeated dissolution and precipitation can be another good option.
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it depends how much acid with inulin you are going to use. The compound looks to be terribly polar. I doubt ether will dissolve the product.
How you purify will depends what reagents you use for the coupling step, For "typical" esterification conditions, it is difficult to generalise purification techniques when you have both acid, amines, and polyols present.
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for example orange peel essential oil in cake.
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Essential oil are the carriers of aromatic, pigmented and volatile compounds in many plant materials. In addition, oils have been reported by many researchers to improve the mouthfeel/ texture of many foods.
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For next semester (Semptember 2017) I'm looking for a master student who would like to study on seafood processing and seafood quality and/or meat processing and meat quality (chemical, sensorial and microbiological quality). In addition, our faculty give schoolarship for all students. If there is someone who is interested in this, please contact with me.
Bests,
ilknur
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yes on two conditions that i will be allowed to start PhD in the same field at same place. find attached my cv
 Regards
ogori A.F
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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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I am using lab-type spray dryer in order to obtain skim milk powder. My outlet temperature is 85-90 C. Moisture content of product is in the range of %3-4. After production i put my powders in desiccator to cooling without obtaining moisture and then i am using top agglomerator for instantizing process. During the agglomeration step i cannot obtain a good flowability from my powders. All powders starts to stick the conical chamber before spraying binder and agglomeration process stops. Inlet air rate 12-14 m3/h and air temperature 60 C . What do you recommend to obtain a good flowability and agglomeration?
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Thanks for your valuable comments 
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We are working on a material that has potential in packaging fresh produce. We want to know how we can quantitatively assess the freshness of the produce.
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Water vapour permeability test is essential for fresh produce packaging material which decides its transpiration and firmness. Also burst strength, puncture test to be carried out for packaging material for its durability.
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I need a detailed simple experimental procedure for the crystallisation of sucrose?  i have read many papers and seen many videos but i need a very scientific approach in terms of mass and temperature. anywhere i can get it? and what seed crystal i can use?
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Dear Selma,
                           first of all, a solubility curve of sucrose in water is needed. If you are interested in, I can send you the data of the sucrose mass as function of temperature.
Secondly, are you working in a lab or your question concerns an industrial production ? If you are working in a lab, the best way is to download the papers published by Mantovani, Vaccari, Sgualdino and Aquilano ( University of Ferrara, Italy). 
My e-mail :   dino.aquilano@unito.it  could help you to solve some crystallization problems for sucrose.
All the best !
Dino
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Dear Saifeldin,
Please see the concept of toxicology written by Dr. Omkar
Krishna
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I need to the compund dinitrophthalic acid or diaminophthalic acid in any position substitution .
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Thanks dear Johannes but this acid contain pyridin as salt
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food chemistry 
fraying potato
degredation of acrylamide  
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you can used HPLC method
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1. FDA stated that low calorie food contains 120 kal/g or less,
2. Tharp & Young on 'Ice Cream: An Encyclopedic Guide to Ice Cream Science' book, stated that most typically, 'reduced calorie' product provide >25% fewer calories per serving than predetermined standard,
3. US regulations stated that low fat ice cream contains 3g fat or less per serving (about 120mL).
However, I couldn't find information  about how many calorie (maximum) are in low-calorie ice cream (based on regulations/ products in general).
Thank you in advance for helping.
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Now low calorie ice creams with low glycemic index are available in market which are stevia or artificial sweeteners like aspartame based. But original taste is altered.
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I work on an ion chromatography system for the separation of anionic species in wine. Since I changed the Guard and Separation Colums, backpressure increased from 1500 to 1900 psi at my working flow (1 ml/min) and I got a poor resolution of closer peaks in the chromatogram. How do I understand which is the cause of this problem? The instrument manual suggests to detach every component and see if it's the responsible of the high backpressure, but I only know the backpressure value of the two columns and not that of the tubings and other components. Moreover, some components are not detachable because they are in the back of the instrument and I can't reach them.
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Bill has linked a very good information to attend such problems. But Dr. Ghosh is also right, we can not resolve all technical faults. Better to consult engineer.
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I am going to produce some solid chocolate and subsequently heat it up to 45 degrees of centigrade for some reason and solidify it again. Is it so necessary to temper the chocolate after production?
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It is altogether new information for me. i do not have expertise in this area, nut it is very interesting to know that  tampering is necessary to avoid fat ballon.
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I have a project making "cold brew" coffee. The ground coffee need to steep into water for 20 - 24h, so this is the good condition for the microorganisms grow. I decided to pasteurize the coffee after that but I worried that the temperature will blow away all the flavor and the coffee will turn into odorless... What I need to do in this case? I glad to see any comments of RGers.
Thanks and Regards
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Interesting points on pulsed electric field treatment for retaining the flavour for longer period.
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I want to know what makes this types of fats incompatible. I know the solid percentage at different ratios of lautric/cocoa butter at different temperatures empyrically obtained but don't understand the science behind it. 
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Very informative and worth reading material in linked files.
As suggested mixing cocoa butter will regulate crystal formation.
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i am looking for articles
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Good points Dr. Benjamin
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Emanuele Boselli
Associate Professor
Vito Verardo
PhD in food Science
Rohan Karawita
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 Good attached link Mr Saadi. Despite the number of biochemical studies exploring algal lipids and fatty acid biosynthesis pathways and profiles, analytical methods used by phycologists for this purpose are often diverse and incompletely described. Potential confusion and potential variability of the results between studies can therefore occur due to change of protocols for lipid extraction and fractionation, as well as fatty acid methyl esters (FAME) preparation before gas chromatography (GC) analyses.  
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in other words, how to enhance the taste of milk in such a product? instead of the starchy after taste. It's worthy to mention that the starch used in the finished product is fully hydrated and cooked, but the after taste is feeling yet.
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If you add fennel or aniseed essential oil. It can mask the effect. 
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Hello, I need some comments, view, literature  regarding the following points
1. How to As metabolism pathway goes with sugar compounds and uptake and metabolism, the synthesis pathway in the marine food web.
2. How to detect the above compound as duterated As by isotope identification method with LC-ICP-MS-MS
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I guess the isoelectric precipitation is favorable one but it can denature the protein.If so,why  this method is used?Can you please explain it?
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The content of casein in milk is determined by two measurements of infrared absorbance in a milk sample by infrared spectrometry before and after a separation of the casein. The casein content is calculated by use of absorbance data recorded during the two absorbance measurements. The new method is considerable faster than the known wet-chemical methods, such as the normal wet chemical reference method for casein determination in milk using a Kjeldahl nitrogen determination of the milk sample, then a coagulation of the milk, and finally a Kjeldahl nitrogen determination of the filtrate. Further the new method provides a more reliable accuracy than the know determination using a single infrared analysis of a milk sample.