# Production of Vegan Ice Cream: Enrichment with Fermented Hazelnut Cake
## 3 Results and Discussions
### Enzyme Inhibition Profiles of Ice Cream Products Before and After In Vitro Digestion  
The inhibitory effects of DIC, HIC, and FHIC on \(\alpha\)-amylase, \(\alpha\)-glucosidase, angiotensin-converting enzyme (ACE), acetylcholinesterase increase (AChE), and lipase activities are presented in Table 8. None of the ice cream samples exhibited \(\alpha\)-amylase or \(\alpha\)-glucosidase inhibition before or after in vitro digestion. Similarly, no significant inhibition was detected in the digestion medium, whereas hazelnut cake and fermented hazelnut cake demonstrated notable enzyme inhibition [9]. The absence of inhibitory activity in ice cream samples may be attributed to the dilution effect, thermal and processing degradation, or structural disruption during digestion. Bioactive enzyme inhibitors from hazelnuts may have been significantly diluted within the ice cream matrix, reducing their concentration below detectable levels. The enzyme-inhibitory compounds (e.g., polyphenols and peptides) naturally present in hazelnut may have been substantially diluted in the ice cream matrix, reducing their concentration below the detection threshold. [PERSON] (2015) reported that milk proteins (particularly caseins) can bind and precipitate polyphenic compounds through hydrophobic interactions and hydrogen bonding, thus reducing measurable activity [58]. Moreover, the high fat content of dairy matrices can partition lipophilic hazelnut bioactives \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Ice Cream**} & **ABTS\({}^{+}\) Radical** & **DPPH Radical** & **Hydroxyl Radical** & **Metal (Fe\({}^{+}\)2)** \\  & **Scavenging Activity** & **Scavenging Activity** & **Scavenging Activity** & **Chelating** \\  & **(umol Trolox/g)** & **(umol Trolox/g)** & **(mg Ascorbic Acid/g)** & **Activity (\%)** \\ \hline DIC & 2.25 \(\pm\) 0.04 \({}^{\text{a}}\) & N.D. & 183.7 \(\pm\) 2.9 \({}^{\text{c}}\) & N.D. \\ HIC & 2.20 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.68 \(\pm\) 0.28 \({}^{\text{a}}\) & 193.7 \(\pm\) 3.4 \({}^{\text{a}}\) & 31.26 \(\pm\) 1.10 \\ FHIC & 2.91 \(\pm\) 0.00 \({}^{\text{a}}\) & 0.73 \(\pm\) 0.23 \({}^{\text{a}}\) & 188.4 \(\pm\) 1.8 \({}^{\text{b}}\) & 2.55 \(\pm\) 0.09 \\ \hline \multicolumn{4}{c}{In vitro digestion} \\ \hline DIC & 11.87 \(\pm\) 0.39 \({}^{\text{c}}\) & 1.44 \(\pm\) 0.04 \({}^{\text{b}}\) & N.D. & N.D. \\ HIC & 4.01 \(\pm\) 0.09 \({}^{\text{b}}\) & 1.71 \(\pm\) 0.06 \({}^{\text{c}}\) & N.D. & N.D. \\ FHIC & 10.03 \(\pm\) 0.13 \({}^{\text{c}}\) & 4.73 \(\pm\) 0.07 \({}^{\text{d}}\) & N.D. & N.D. \\ \hline \hline \end{tabular}  
* Values are given as mean \(\pm\) standard deviation. If the letters (a–d) used as superscripts are the same, there is no difference between the samples produced with different formulations (\(p>0.05\)). N.D.: Not detected.  
\end{table} 
Table 7: Antioxidant activities of ice cream products. into the lipid phase, making them inaccessible for aqueous extraction [59]. The complex ice cream matrix (containing proteins, fats, and emulsifiers) can physically encapsulate bioactive compounds, as shown in studies on nutraceutical delivery in frozen desserts [60]. In addition, inhibitory compounds may have been inactivated during ice cream production due to processing conditions, such as pasteurization, homogenization, aging, and freezing, or bioactive peptides responsible for inhibition may have been hydrolyzed or structurally altered in the gastrointestinal environment [1; 61]. Before digestion, negligible ACE inhibition (0.76 \(\pm\) 0.01%) was noted exclusively in HIC, whilst other samples exhibited no measurable action, perhaps due to quantities falling below the assay's detection threshold. Post-digestion, ACE inhibition increased significantly, with values ranging from 4.85 \(\pm\) 0.03% to 7.42 \(\pm\) 0.08%. The observed increase in ACE-inhibitory activity following in vitro digestion is primarily attributed to the enzymatic hydrolysis of milk and hazelnut proteins, which liberates bioactive peptide sequences capable of ACE inhibition [62; 63; 64].