A rapid analytical and quantitative evaluation of formaldehyde in squid based on Tri-step IR and partial least squares (PLS)

• Published in: Food chemistry Vol. 229; pp. 458 - 463
• Main Authors: Gu, Dong-Chen, Zou, Meng-Jun, Guo, Xiao-Xi, Yu, Pan, Lin, Zhi-Wei, Hu, Tu, Wu, Ya-Fen, Liu, Yuan, Gan, Jian-Hong, Sun, Su-Qin, Wang, Xi-Chang, Xu, Chang-Hua
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.08.2017
• Subjects: Animals; Decapodiformes - chemistry; Food Contamination - analysis; Formaldehyde; Formaldehyde - analysis; Least-Squares Analysis; Limit of Detection; Partial least squares; Quantitative detection model; Spectral curve-fitting analysis; Spectrophotometry, Infrared - methods; Squid (Illex argentinus); Tri-step infrared spectroscopy; Quantitative detection model; Squid (Illex argentinus); Spectral curve-fitting analysis; Partial least squares; Formaldehyde; Tri-step infrared spectroscopy
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2017.02.082

•Tri-step IR was developed for qualitative and quantitative profiling of squids.•Formaldehyde concentration in squid soaked water play a role in formaldehyde in squid.•Spectral curve-fitting was applied to further disclose the variation rule of protein secondary structure.•Tri-step IR combined with PLS can accurately predict formaldehyde concentration in squids. Formaldehyde abuse for retaining squid freshness is detrimental to public health. The aim is to establish a rapid and quantitative detection method of formaldehyde in squid for screening massive samples. A linear relationship between formaldehyde concentration in squid and formaldehyde concentration in squid soaked water was observed using HPLC. Chemical profile variances of squids were rapidly analyzed by Tri-step infrared spectroscopy. Specifically, with increasing formaldehyde concentration, peak intensities of 2927cm−1 (vas(CH2)), 1081cm−1 (glycogen), 1631cm−1 (β-sheet proteins) decreased while 1655cm−1 (α-helix proteins) increased. Spectral curve-fitting results further disclosed that β-sheet proteins were transformed to α-helix and β-turn conformations. Furthermore, a quantitative prediction model based on IR spectra was established by PLS (R2, 0.9787; RMSEC, 5.51). The developed method was applicable for rapid (c.a. 5min) and quantitative analysis of formaldehyde in squids with LOD of 15mg/kg.