## 3 Results and Discussion
### Use of Phenolic Compounds to Inhibit or Block the Maillard Reaction in Bakery Products
#### 3.5.2 Biscuits  
The effect of phenolic compounds as inhibitory agents of MRPs was also investigated in biscuits. These were added in the form of powders, extracts, and pure standards.  
[PERSON] et al. investigated the effect of fennel (_Foeniculum vulgare_ L.) and black cumin seeds (_Nigella sativa_ L.), also known as Nigella or black seeds, on the acrylamide content in conventionally and microwave-cooked biscuits [36]. The two ingredients were included in the form of a powder in different amounts: 2, 4, and 6%. The highest content of acrylamide was found in conventionally baked biscuits; however, it was observed that the addition of fennel and Nigella had a positive effect on these biscuits. Fennel addition decreased acrylamide levels in conventionally baked biscuits and resulted in a concentration of acrylamide equal to the minimum limit of quantitation in microwave-baked biscuits. As a matter of fact, fennel addition at 2, 4, and 6% diminished the acrylamide content by 38, 61, and 78%, respectively [30]. The addition of Nigella also had a positive effect on the acrylamide content. The decrease was about 60% in conventionally baked biscuits (355.2 vs. 138.6 \(\upmu\)g/kg) and 68% (306.9 vs. 97.8 \(\upmu\)g/kg) in microwave-baked biscuits [36].  
Based on these findings, it can be speculated that besides the positive effect of the cooking method (microwave cooking minimizes acrylamide formation due to the temperatures being lower than 120 \({}^{\circ}\)C), the high antioxidative activity of the two additives positively affects the inhibition of acrylamide. Antioxidative compounds are effective in reducing the acrylamide formation because of the following: (i) carbonyl trapping, (ii) the reduction in sugar degradation through Maillard reaction processes, and (iii) radical-scavenging activities [36]. In addition, some flavonoids can decrease acrylamide formation because of the number of phenolic hydroxyl groups [42].  
The effect of lotus-seedpod oligomeric procyanidins on the inhibition of AGE formation in tough biscuits was also investigated [37]. It emerged that the formation of fluorescent AGEs was significantly inhibited by this enrichment. It is possible that the phenolic compounds had antiglycative activity that was attributable to the capture of dicarbonyl compounds and antioxidative activity by scavenging free radicals and metal-ion chelation.  
Biscuits were also formulated by adding pure standards of single phenolic compounds (i.e., hydroxytyrosol, quercetin, and gallic acid) and an olive-leaf extract at different concentrations up to 0.75% (\(w/w\)) of the total solid content [35]. Following the addition of hydroxytyrosol (HT), a significant reduction in the 3-DG content of biscuits, compared with the control, was observed. The increase in HT enrichment resulted in a higher reduction in 3-DG content. When the dough was formulated with 6.15 and 12.31 mg HT/g, 3-DG formation was reduced by 37.9% and 41.6%, respectively. On the contrary, the addition of gallic acid resulted in an increase in 3-DG content. As regards the formation of free Maillard-derived fluorescent compounds, the addition of quercetin was the most effective against the formation of this class of compounds (64.9% inhibition), followed by HT addition, which exerted an inhibitory activity of 28.8%. The biscuits enriched with gallic acid, or the extract of olive leaves showed an inhibitory activity of below 10%; the free-fluorescent-AGE concentration was not statistically different to that in the control sample. However, similar antiglycative activity for pentosidine was observed for the biscuits enriched with the olive-leaf extract. It was speculated that other structures contained in the extract may have contributed synergistically to the antiglycative activity.