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    Production of Vegan Ice Cream: Enrichment with Fermented Hazelnut Cake
    (MDPI, 2025) Aydemir, Levent Yurdaer; Demir, Hande; Erbay, Zafer; Kilicarslan, Elif; Salum, Pelin; Ozdemir, Melike Beyza
    The growing demand for sustainable plant-based dairy alternatives has spurred interest in valorizing agro-industrial byproducts like hazelnut cake, a protein-rich byproduct of oil extraction. This study developed formulations for vegan ice cream using unfermented (HIC) and Aspergillus oryzae-fermented hazelnut cake (FHIC), comparing their physicochemical, functional, and sensory properties to conventional dairy ice cream (DIC). Solid-state fermentation (72 h, 30 degrees C) enhanced the cake's bioactive properties, and ice creams were characterized for composition, texture, rheology, melting behavior, antioxidant activity, and enzyme inhibition pre- and post-in vitro digestion. The results indicate that FHIC had higher protein content (64.64% vs. 58.02% in HIC) and unique volatiles (e.g., benzaldehyde and 3-methyl-1-butanol). While DIC exhibited superior overrun (15.39% vs. 4.01-7.00% in vegan samples) and slower melting, FHIC demonstrated significantly higher post-digestion antioxidant activity (4.73 mu mol TE/g DPPH vs. 1.44 in DIC) and angiotensin-converting enzyme (ACE) inhibition (4.85-7.42%). Sensory evaluation ranked DIC highest for overall acceptability, with FHIC perceived as polarizing due to pronounced flavors. Despite textural challenges, HIC and FHIC offered nutritional advantages, including 18-30% lower calories and enhanced bioactive compounds. This study highlights fermentation as a viable strategy to upcycle hazelnut byproducts into functional vegan ice creams, although the optimization of texture and flavor is needed for broader consumer acceptance.
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    Öğe
    Upgrading the Bioactive Potential of Hazelnut Oil Cake by Aspergillus oryzae under Solid-State Fermentation
    (Mdpi, 2024) Ozdemir, Melike Beyza; Kilicarslan, Elif; Demir, Hande; Koca, Esra; Salum, Pelin; Berktas, Serap; Cam, Mustafa
    Hazelnut oil cake (HOC) has the potential to be bioactive component source. Therefore, HOC was processed with a solid-state fermentation (SSF) by Aspergillus oryzae with two steps optimization: Plackett-Burman and Box-Behnken design. The variables were the initial moisture content (X-1: 30-50%), incubation temperature (X-2: 26-37 degrees C), and time (X-3: 3-5 days), and the response was total peptide content (TPC). The fermented HOC (FHOC) was darker with higher protein, oil, and ash but lower carbohydrate content than HOC. The FHOC had 6.1% more essential amino acid and benzaldehyde comprised 48.8% of determined volatile compounds. Fermentation provided 14 times higher TPC (462.37 mg tryptone/g) and higher phenolic content as 3.5, 48, and 7 times in aqueous, methanolic, and 80% aqueous methanolic extract in FHOC, respectively. FHOC showed higher antioxidant as ABTS(+) (75.61 mu mol Trolox/g), DPPH (14.09 mu mol Trolox/g), and OH (265 mg ascorbic acid/g) radical scavenging, and alpha-glucosidase inhibition, whereas HOC had more angiotensin converting enzyme inhibition. HOC showed better water absorption while FHOC had better oil absorption activity. Both cakes had similar foaming and emulsifying activity; however, FHOC produced more stable foams and emulsions. SSF at lab-scale yielded more bioactive component with better functionality in FHOC.