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Title: TWO-DIMENSIONAL VISIBLE/NEAR-INFRARED CORRELATION SPECTROSCOPY STUDY OF THERMAL TREATMENT OF CHICKEN MEATS

Author
item LIU, YONGLIANG - VISITING SCIENTIST--CHINA
item Chen, Yud
item OZAKI, YUKIHIRO - KWANSEI-GAKUIN U., JAPAN

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/1999
Publication Date: 9/16/2000
Citation: N/A

Interpretive Summary: The U.S. legislation requires that each poultry carcass at poultry slaughter plants be inspected by Food Safety and Inspection Service (FSIS) inspectors. Visual and manual inspection on-line by inspectors is prone to human error and day-to-day and inspector-to-inspector variations. We have developed a visible/near-infrared (NIR) spectrophotometer system aiming to improve the effectiveness of the U.S. federal safety inspection program an increase the productivity of processing plants. However, to facilitate the mathematics model and select the characteristic spectral wavelengths, it is necessary to explore the fundamental visible/NIR spectral features of both wholesome and unwholesome meats, with the aid of not only other spectrophotometers such as infrared (IR) and Raman technique, but also advanced spectral data analysis such as the newly-developed two-dimensional (2D) correlation method. Currently, a scarcity of literature is available regarding the spectroscopic investigation of various meat products. We present the results of applying 2D correlation analysis for the characterization of the spectral wavelengths of thermally treated chicken meat in the visible/near-infrared region. The results of this approach will not only strengthen the scientific understanding of heat-induced compositional change of meats, but also be able to elucidate the band origins in this region, which, in turn will improve the design of the visible/NIR spectrophotometer system for poultry inspections. Researchers working on visible/near-infrared spectroscopy of food and agricultural products will benefit from the findings of this research.

Technical Abstract: The thermal treatment of chicken meats was investigated by generalized two-dimensional (2D) visible/near-infrared (NIR) correlation spectroscopy. The chicken meats were cooked at various intervals of time in a convection oven under a constant air temperature of 150 degrees Centigrade, and their visible/NIR spectra were collected over the region of 400-2500 nm. Synchronous 2D correlation analysis revealed at least two bands around 445 and 560 nm (in 400-700 nm visible region) whose intensities decrease with cooking, and the corresponding asynchronous spectrum indicated that the spectral intensity reduction of the two bands actually occurs before (at a lower temperature) the intensity variation of other bands at 475, 520, and 585 nm. It suggested that 445 and 560 nm bands are ascribed to deoxymyoglobin and oxymyoglobin, and at least one of the 475, 520, and 585 nm bands assignable to the denatured species (metmyoglobin) of myoglobin. The asynchronous 2D correlation spectra in NIR regions showed that C-H bands change their spectral intensity before the O-H group, indicating that C-H fractions attributed to heme groups in deoxymyoglobin and oxymyoglobin are easily oxidized and denatured. In addition, strong correlation peaks were observed in the 2D correlation of the bands in visible, short-wave NIR (SW-NIR) and NIR spectral regions. The band at 445 nm (or 560 nm) is correlated synchronously and positively with the bands at 980, 1195, 1360, and 1655 nm, indicating that these bands share identical time-dependent patterns and all arise from the same species. The result provided an intriguing possibility of correlating various absorption bands in different regions to establish unambiguous assignments.