Sensing protein oxidation by spectroscopy - Find a marker from nutrition and digestion point of view -

2019 Fiscal Year Annual Research Report

• Project/Area Number: 19F19104
• Research Institution: National Agriculture and Food Research Organization
• Principal Investigator: 本山 三知代 国立研究開発法人農業・食品産業技術総合研究機構, 畜産研究部門, 主任研究員 (20414683)
• Co-Investigator(Kenkyū-buntansha): DUCONSEILLE ANNE 国立研究開発法人農業・食品産業技術総合研究機構, 畜産研究部門, 外国人特別研究員
• Project Period (FY): 2019-10-11 – 2022-03-31
• Keywords: Meat cooking / Microscopy / TBARS / Raman / Review

Outline of Annual Research Achievements

Beef meat samples have been obtained from the market, as well as chemical reagents and experimental devices. As the cooking condition, three different methods have been tested and then implemented.
Beef samples have been cut into a certain form and cooked with these three methods at two endpoint temperatures. Raman spectroscopy has been applied immediately after to the samples and some spectra were acquired. Unfortunately, the excitation laser source of the Raman device has broken down, so this experiment has been unavoidably postponed.
Using the meat samples, histological observations with an optical microscopy has been performed. Samples were fixed, sectioned and stained. The images obtained are currently under analysis using the imageJ software.
Measurement of lipids oxidation has been settled through TBARS measurement. Some adjustments are necessary to measure lipids oxidation of the cooked samples.
In parallel, a review of the scientific literature regarding the impact of cooking on nutritional potential of beef is under writing.

Current Status of Research Progress

3: Progress in research has been slightly delayed.

Reason

First of all, Raman spectroscopy has been settled and the analysis has also begun during Reiwa1, however, the Raman-excitation laser has broken down unfortunately. Currently, we don't know when it can be fixed yet because of the effect of the new corona virus outbreak.
DNPH reagents which are necessarily to measure DNPH level of meat after cooking were arrived late. TBARS measurement was therefore tentatively implemented instead of the DNPH measurement.
The corona virus situation obliged us to stop the experiments for about 2 months, and our possibility to access office and experimental facilities is still substantially limited. For these reasons, the experiments have been delayed.

Strategy for Future Research Activity

The content of the basic constituents (lipids, protein and moisture) of the meat sample will be measured. This information is necessary to compare the oxidation level of proteins and lipids of all the samples. Then, a DNPH measurement will be performed to the raw meat samples and the ones which are cooked in the same way for the TBARS measurement.
To conduct in vitro digestion experiments on the raw and cooked meat, all the reagents and enzymes which are necessary should be received and evaluated their activity before the experiments. It should also be tested several digestion protocols which are exist so far and establish/select one protocol to be applied to our samples.
The obtained digested materials will be freeze-dried and Mass spectroscopy will be performed to assess the peptides profile of each samples. This will give information on the digestibility of meat cooked in different methods.
When the Raman laser is repaired, we will restart to acquire the Raman spectra of all raw and cooked meat. If there is time, infrared spectra will be also acquired, in order to obtain complementary information on the chemical changes occurring in meat under different cooking methods.