Assessment of proteolysis in ultra‐high temperature milk using attenuated total reflectance–Fourier transform infrared spectroscopy

Abstract

This study investigated the suitability of attenuated total reflectance–Fourier transform infrared spectroscopy (ATR‐FTIR) as an alternative technique to assess proteolysis in ultra‐high temperature (UHT) milk. Commercial UHT milk samples were stored (5 and 30 °C) and analysed for four months. Milk samples were treated with acetic acid and trichloroacetic acid to obtain milk extracts containing peptides. The concentrated extracts were subjected to ATR‐FTIR, and the spectrum was obtained. Results were compared with techniques like high‐performance liquid chromatography, fluorescamine and 2,4,6‐trinitrobenzenesulphonic acid. The present study indicated that ATR‐FTIR‐based method can be used as an alternative method for assessing proteolysis in UHT milk.

Application of LC‐HRMS identified marker peptides in an LC‐MS/MS method for detection and quantification of heat‐resistant proteolytic activity in raw milk

“…Direct detection methods for AprX enzymatic activity such as the spectrophotometric TNBS, the OPA or azocasein method or the fluorometric FITC-casein method are not sensitive enough for fast detection of low AprX levels (reviewed by Zhang et al 2019). The same probably applies for total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) which was recently investigated as an alternative rapid technique to assess proteolysis in UHT milk stored for up to 4 months (Ranvir et al 2020). Detection of the peptide profile from casein hydrolysis through RP-HPLC or LC/MS is promising and generates more specific information on peptides which are related to spoilage.…”

“…The same probably applies for total reflectance–Fourier transform infrared spectroscopy (ATR‐FTIR) which was recently investigated as an alternative rapid technique to assess proteolysis in UHT milk stored for up to 4 months (Ranvir et al . 2020). Detection of the peptide profile from casein hydrolysis through RP‐HPLC or LC/MS is promising and generates more specific information on peptides which are related to spoilage.…”

Application of Spectroscopic Techniques to Evaluate Heat Treatments in Milk and Dairy Products: an Overview of the Last Decade

“…The determination of the time of heating varies depending on the product characteristics (e.g., liquid without particles, liquid with particles, solid, volume, density), the type of heat transfer applied (e.g., conduction or convection), and the heating system used (e.g., indirect or direct). However, in recent years, new technologies such as microwaves (Martins et al, 2019), infrared (Aboud et al, 2019), ohmic (Cappato et al, 2017), and radio frequency (Di Rosa et al, 2018) have (Firmani et al, 2020) Milk UHT ATR-IR ATR-IR can be exploited to assess proteolysis in UHT milk (Ranvir et al, 2020) Milk Heat treatment (25-80°C) FTIR + NMR Mineral behaviors are affected by thermal heating (Boiani et al, 2018) Milk powders Heat treatment (25-100°C) FTIR The main changes in the secondary structure of proteins appear at a temperature higher than 70°C in whole milk and in infant formula at 50°C. The β-structures (β-sheet and β-turn) in the whole milk powder both decreased in the range of 70 to 85°C, whereas α-helix structures increased.…”