Determination of Maillard reaction level and its effects in maize silage by different imaging techniques and analytical methods

In this doctoral study, it was aimed to determine the Browning Index (BI) level and its effects, as a measure of the Maillard reaction occurring during the fermentation of maize silage, through different analytical methods including Imaging Analysis, Penn State Particle Size Separator, Spectrophotometry, Chromatography, Chemical Analyses, In Vitro Gas Technique, and In Vitro Digestibility. In this research, the browning (Browning Index, BI) resulting from Maillard reactions in 20 corn silages collected from dairy farms in Konya province was determined by a digital imaging device with CIE Lab* colour analysis equipped with a special apparatus. Nutrient compositions, fermentation kinetics (measured by an Automated Modular In Vitro System), and in vitro digestibility levels of the silage samples were determined. The relationships between BI/colour parameters and fermentation and digestibility parameters were investigated in fresh, dried, and ground silages. It was determined that drying caused changes in colour parameters, and BI, which is considered as an indicator of heating, could be detected better in fresh and whole silages (p<0.05). Negative correlations were found between BI values and crude protein (CP) (r=-0.47, p<0.01), neutral detergent insoluble crude protein (NDICP) (r=-0.53, p<0.01), and acid detergent insoluble crude protein (ADICP) (r=-0.35, p<0.01). It was determined that as the BI values, which indicate Maillard reactions, increased, proteins remained bound within cell wall fractions, thereby reducing the possibility of digestion. Among the colour parameters, positive correlations were determined between L* and the fermentation rate per hour (SFO) (r=-0.23, p<0.01), asymptotic gas production amount (VF) (r=-0.26, p<0.01), and the time to reach the maximum degradation rate (EY Kd) (r=-0.25, p<0.01). It was understood that among the colour parameters, a* had negative correlations with fermentation kinetic parameters at different levels of significance. It was determined that there were also negative correlations between BI, which indicates the degree of heating, and general kinetic parameters, and that heating adversely affected fermentation It was determined that as the BI values, which indicate Maillard reactions, increased, proteins remained bound within cell wall fractions, thereby reducing the possibility of digestion. In this research, it was concluded that the determination of colour changes caused by heating of maize silage can provide rapid and practical information under field conditions about silage quality criteria, fermentation properties, and digestibility. Keywords: Maillard reaction, corn silage, cattle