Questions related to Food Chemistry
I want to do the PV using spectrophotometric method. The problem is that linear curve of cumene hydroperoxide can not be able to obtain. Later, i find in some paper, chloroform is having high absorbance in blank reading. Chloroform with ethanol as preservatives is recommended. In another paper, it is mentioned about the modified method of Richards and Hultin (2002) along with the concentration range of cumene hydroperoxide.
Enzymatic hydrolysis has emerged as a highly effective approach for obtaining bioactive peptides. Is there an extensive investigation into the impacts of enzymatic hydrolysis on the physicochemical properties of proteinaceous raw materials and the subsequent processing of enzymatically hydrolyzed proteins in the domains of feed or food? Furthermore, are there any notable scholars specializing in research related to this area?
Lipids are highly soluble in non-polar solvent but not in polar solvent like water. What is the explanation for this phenomenon from the point of view of their chemistry?
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?
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
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.
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?
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?
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.
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.
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?
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.
Which molecular properties cause oil rancidification other than unsaturated C-C bond? Does ester bond braking rancidification continue without moisture?
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.
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?
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?
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.
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!
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!
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?
Does it have something to do with its ketone group or a different property? Please explain.
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?
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
n is Avrami exponent
I don't understand how "k" and "n" can be measured?
I appreciate your guidance.
I want to publish my paper. So I want to know some recognized conference.
Areas focused : food chemistry / bioactive compounds/nutrition
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!
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.
I want to ask about how to calculate the total carotenoids in an extract using the spectrophotometer.
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?
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.
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?
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?
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.
What is the indicated methodology to perform sedimentation, viscosity and turbidity test for fruit juices ?
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.
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?.
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
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
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 ?
Hi, I want to conduct an accelerated shelf life testing of packaged coconut water. What can be the possible acceleration factor for the same.
The method which relevant to analysis of above mention sweeteners by using HPLC-UV/DVD
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
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??
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.
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.
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?
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?
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.
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?
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.
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.
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?
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
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.