Inhibition of Maillard reaction during alkaline thermal hydrolysis of sludge
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Published on: May 19, 2019
Ning Yang1, Shucheng Yang1, Xing Zheng2
1Department of Environmental Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Abstract:
The Maillard reaction (MR) occurs during the alkaline thermal hydrolysis (ATH) of sludge, which affects the quantity and quality of recovered protein. In this paper, four different sulfites were added to investigate their inhibitory effects on melanoidin production. The results showed that sulfites inhibited melanoidin production during ATH of sludge and the inhibitory rate increased with their concentration. At a concentration of 5.71 g/L, the inhibitory rates of NaHSO3 on melanoidin were 63.27%. Furthermore, the 3D-EEM (Three-Dimension Excitation-Emission-Matrix) fluorescence spectroscopy and protein testing data showed that the inhibition of melanoidin production was accompanied by an increased protein concentration, and protein increased with increasing sulfites concentration. A 2.5-fold increase in protein concentration with Na2S2O4 significantly enhanced the quantity of protein recovered. Therefore, the addition of sulfite during ATH of sludge reduces the amount of non-biodegradable melanoidin, which in turn benefits protein recovery.
Insights
Adding sulfites during alkaline thermal hydrolysis of sludge inhibits melanoidin production. This process enhances protein recovery by reducing non-biodegradable compounds.
Area of Science:
- Environmental Science
- Biochemistry
- Chemical Engineering
Background:
- The Maillard reaction (MR) is a significant process during alkaline thermal hydrolysis (ATH) of sludge.
- MR impacts the yield and quality of proteins recovered from sludge.
Purpose of the Study:
- To investigate the inhibitory effects of four different sulfites on melanoidin production during ATH.
- To evaluate the impact of sulfites on protein recovery.
Main Methods:
- Alkaline thermal hydrolysis (ATH) of sludge with the addition of four different sulfites.
- Measurement of melanoidin production and inhibition rates.
- Three-Dimension Excitation-Emission-Matrix (3D-EEM) fluorescence spectroscopy.
- Protein concentration testing.
Main Results:
- Sulfites effectively inhibited melanoidin production during ATH, with inhibition rates increasing with concentration.
- Sodium bisulfite (NaHSO3) achieved a 63.27% inhibition rate at 5.71 g/L.
- Inhibition of melanoidin production correlated with increased protein concentration.
- Sodium dithionite (Na2S2O4) resulted in a 2.5-fold increase in protein concentration, significantly enhancing protein recovery.
Conclusions:
- Sulfites reduce the formation of non-biodegradable melanoidins during ATH of sludge.
- The addition of sulfites improves the quantity and quality of recovered proteins.
- This strategy offers a viable method for enhanced protein recovery from sludge.
