Recently, I wish to do protein quantification test for validating the total protein (%) in poultry feed (Powder form). I did some paper readings about suitable methods to measuring total protein residing within poultry feed. Mostly, the authors mentioned about the complex methods such as Kjeldahl, Dunmas and NIR methods for such purposes. However, for my case, the purity of the protein sample or breakdown of other substances aside from protein does not required. I just want to know how much total protein (%) within the poultry feed. I wonder that is there any simple and efficient methods to measure the total protein in poultry feed (Powder or Liquid)? Does the UV spectroscopy methods such as Bradford or Lowry method applicable for such purposes?
Be aware that most methods measure N content and not protein! The milk powder fraude in China a number of years ago, illustrate the possible disastrous effects if one is not aware of that.
C.A. (Kees) Kan thanks for the reply. Maybe my question is a little unclear and yes I'm aware that most methods measure N content. What I try to ask is that is there any simple methods to determine total N contents from protein sources disregarding any ingredients such as carbohydrates and glycerol that could be present (Example: animal poultry feed or daily products)?
Dear Patrick, having been involved in poultry nutrition research for over 30 years, I wonder why total protein is your main topic. Levels of limiting amino acids like methionine and lysine are better indicators of animal performance in my view. Being retired for over a decade, I am not up to date with recent developments in simple N or protein analyses.
C.A. (Kees) Kan Oh I see. Thank you for your insight. For my case, the purpose of knowing the total protein within the suspected food product (Example: Poultry feed) is mainly for the food product evaluation to match the industry standard criteria after production. As my question may seems weird, but my main focus basically works towards protein content (%) evaluation as one of the Product Quality Control. As for the level of specific amino acids such as methionine, we often go for the HPLC-UV routine analysis to provide a clear view to ensure even better product control. Hope my answer can clarify some of your confusions. I apologize if there's any misunderstanding.
Dear Patrick, provided that you have adequate calibration curves, I would think that NIRs should be the method of choice being fast and not requiring extensive sample preparation or chemicals.
C.A. (Kees) Kan I see. NIR seems to be the best choice for me to performing such tasks. However, I'm wondering what are the other options which are simple but efficient methods (Eco-Friendly and Low cost) unlike Kjeldahl methods (Expensive and hazardous) that are available to use in case that NIR is not an option? By asking this question to myself, basically trying to create a backup plan for such task in case of unavailability of using NIR. I wonder as well that does UV spectrophotometry methods such as Bradford and Lowry method applicable to such tasks since they had been around since the old days (Especially Lowry) and usually being used for estimation of protein concentration?
Dear Patrick, I am not familiair with the specific pro's and cons of Bradford or Lowry. Generally UV methods are neither very sensitive nor very specific. Also their accuracy might not be sufficient to be used for quality control purposes.
I see. Ok then I may try to dig a little more paper readings for more informations or maybe develop new methods. Thank you, I appreciate the help and tips.
Looking at the discussion, I see that you have the same problem that I once had, to determine the true contributions of N (NPN and True P). We only did validations between kjeldahl and HPLC.
- Badges
- Science topic
- Similar topics
- Phytochemistry
- Extracts