Monitoring Chemical and Physical Changes during Thermal Flavor Generation

Abstract

On-line techniques were developed to monitor chemical and physical changes occurring during the heating of skim milk powder (SMP). Atmospheric pressure chemical ionization mass spectrometry (APCIMS) followed the generation and release of volatile compounds from SMP in a packed-bed reactor. Operating conditions were optimized to avoid condensation of high boiling compounds such as maltol, and the system was highly reproducible (CV < 7%). Differential scanning calorimetry (DSC) of SMP identified a potential glass transition at an onset temperature of 67.9 degrees C and a series of exothermic events that were related to different stages of the Maillard reaction. No lactose crystallization was found after heating. Using a heated stage reflectance FTIR device, spectra were obtained at different temperatures. Analysis of the data showed a correlation between the intensity ratio at wavenumbers 1017 and 1064 cm(-1) and the glass transition measured by DSC. This FTIR system was not sensitive enough to detect Maillard intermediates. Combining data from the three techniques provides a fuller picture of the physical changes during the Maillard reaction and their effects on the chemical reactions.

An instrumented oven for the monitoring of thermal reactions during the baking of sponge cake

“…doi:10.1016/j.jfoodeng.2010.07.003 repeatable experimental data and the development of an instrumented reactor is therefore essential. Turner et al (2002) developed on-line techniques to monitor the chemical and physical changes occurring during the heating of milk powder. Their device provided a full picture of the physical changes occurring during the Maillard reaction and their effects on chemical reactions.…”

Antioxidant and Antiproliferative Activities of Heated Sterilized Pepsin Hydrolysate Derived from Half-Fin Anchovy (Setipinna taty)

“…The vibration regions of the amide bonds of proteins and the chemical fingerprints of carbohydrates were readily identified in FT-IR spectroscopy [26,27]. The most distinctive spectral features for proteins were amide I band at 1600–1700 cm −1 (C═O stretching), amide II band at 1500–1550 cm −1 (N–H deformation) and amide III band at 1200–1300 cm −1 (C–N stretching and N–H deformation).…”

“…A series of overlapping peaks located in the region of 1180–953 cm −1 , which were described as the “saccharide” bands resulting from vibration modes such as the stretchings of C–C and C–O and the bending mode of C–H bonds. These absorptions were weak in the spectra of most proteins [27]. …”

On‐Line Monitoring of Flavour Processes

“…Volatile products of the Maillard reaction were monitored using APCI (Turner et al, 2002a), and then the physical state of the solid reactant matrix was monitored using physical techniques such as reflectance Fourier transformed infrared (FTIR) (Turner et al, 2002b;Sivasundaram et al, 2003). A series of publications from the Nestle research laboratories documented the work on coffee flavour generation during roasting (Yeretzian et al, 2000(Yeretzian et al, , 2002Dorfner et al, 2003).…”