## 3 Results and Discussion
### Analysis of Volatile Compounds in Muffins  
The approach used for the determination of the volatile fraction in muffins is based on the headspace analysis by solid-phase microextraction (HS-SPME) technique [52; 53] combined with gas chromatography/mass spectrometry (GC/MS), analytical technique chosen in order to separate and identify the different extracted volatile compounds [54; 55]. The volatile compounds of muffin samples (M_MUF, T_MUF, and C_MUF), were extracted from the solid matrix by DVB/CAR/PDMS fiber and then analyzed by GC/MS. In Figure 8 are reported the GC profiles obtained analysing the muffin samples (M_MUF, T_MUF, C_MUF). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Muffin** & **TPC** & **TAC** & **IC\({}_{50}\)(mg mL\({}^{-1}\))** \\  & **(MeqCT/g Muffin)** & **(MeqCT/g Muffin)** & **DPPH Radical** & **ABTS Radical** \\ \hline
**T\_MUF** & 0.00175 \(\pm\) 0.00012 a & 0.00107 \(\pm\) 0.00007 a & 1.236 \(\pm\) 0.027 b & 0.098 \(\pm\) 0.004 b \\
**M\_MUF** & 0.00120 \(\pm\) 0.00010 b & 0.00062 \(\pm\) 0.00003 b & 2.251 \(\pm\) 0.035 a & 0.789 \(\pm\) 0.013 a \\
**C\_MUF** & - & - & - & - \\
**Positive control** & & 0.1086 \(\pm\) 0.0124 & 4.785 \(\pm\) 0.126 & 1.654 \(\pm\) 0.099 \\ Ascorbic acid & & & \\ \hline TPC = Total Phenolic Content; TAC = Total Antioxidant Capacity; CT = Catechin; DPPH = 2,2\({}^{\prime}\)-dienryl-1- picrylidrazil; ABTS = 2,2\({}^{\prime}\)-azino-bis(3+ethylemiao-6-sulphonic)C\_MUF = Muffin prepared by C\_BP; M\_MUF = Muffin prepared by M\_BP; T\_MUF = Muffin prepared by T\_BP. () = not detected. & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Antioxidant properties of the prepared muffins. Data are presented as mean \(\pm\) SD (\(n=3\)), different letters in the same columns are statistically different (\(p<0.05\)). In the GC profiles (Figure 8) of the analyzed samples, about 29 volatile compounds, belonging to different chemical classes, were tentatively identified by matching the corresponding mass spectra to those of the mass spectral library or by comparing retention times and mass spectra with those of available standards (Table 4). The relative peak area percentage for each compound was defined as the ratio between the peak area for that compound and the sum of all identified peaks areas in that sample. Figure 8: HS-SPME/GC–MS (EI) analysis of: (**a**) muffin sample M_MUF; (**b**)muffin sample T_MUF; (**c**) muffin sample C_MUF. M_MUF = Muffin prepared by M_BP; T_MUF = Muffin prepared by T_BP; C_MUF = Muffin prepared by C_BP. Numbers 1-29 indicate the identified compounds reported in Table 4.  
The obtained aromatic profiles are due to several factors, mainly related to the lipid oxidation and thermal degradation of sugars and free amino acids through caramelization and Maillard reactions during cooking. They are characterized by the presence of aldehydes, hydrocarbons, ketones, alcohols, furrans, pyrazines, and sulphur-containing compounds. Concerning aldehydes, the presence of 3-methylbutanal, 2-methylbutanal, hexanal, nonanal, heptanal, 2-furancarboxaldehyde, octanal, and benzaldehyde was observed (Table 4). 3-methylbutanal (tR = 3.72 min., analyte 3, Table 4), detected in all muffin samples and responsible of malty odour, is an aldehyde deriving from oxidative deamination and decarboxylation of leucine in the presence of carbonyl compounds (Strecker degradation), while 2-methylbutanal (Sample T_MUF) is originated from isoleucine. In Table 4, it can be observed that hexanal, a typical compound of linoleic and arachidonic acids oxidation, is the major aldehyde component in all analyzed muffin samples, followed by nonanal, heptanal, and octanal, the latter of which is detected only in C_MUF, which are formed by oxidation of oleic acid [56]. Benzaldehyde, detected in samples T_MUF and C_MUF, which can be considered a Strecker aldehyde, originated from the reaction of the parent \(\alpha\)-amino acid (phenylglycine) with \(\alpha\)-dicarbonyl compounds from lipid decomposition [56].