Impact of sugar concentration on microbial growth, rheological properties and volatile compound profile during fermentation of hazelnut-based water kefir
Journal of Food Measurement and Characterization, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s11694-026-04900-y
- Dergi Adı: Journal of Food Measurement and Characterization
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, Food Science & Technology Abstracts, Natural Science Collection (ProQuest), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: Fermentation kinetics, Hazelnut cake, Rheological properties, Volatile aroma components, Water kefir
- Trakya Üniversitesi Adresli: Evet
Özet
This study investigated the effects of different sugar concentrations (0%, 2.5%, 5%, 7.5%) on the fermentation dynamics of hazelnut-based water kefir produced using defatted hazelnut cake. Acidification kinetics, microbial growth, rheological properties, and volatile aroma components were analyzed during fermentation (0–72 h). Hazelnut cake, due to its high protein (43.77%) and mineral content, supported the growth of lactic acid bacteria (LAB) and yeast by providing a nitrogen source, which is limited in traditional sugar water media. In the hazelnut-based medium, the numbers of LAB and yeast reached 8.54 and 7.60 log cfu/mL, respectively, depending on the sugar concentration. Rheological analyses revealed pseudoplastic flow behavior in all samples, due to the network structure formed by hazelnut proteins, and the highest consistency index was observed at the sample including 5% sugar (806.5 mPa·s). When the volatile component profile was evaluated, a significant increase in ethanol, acetic acid, esters, and CO₂ formation was observed in parallel with the increase in sugar content. Indeed, in the sample containing 7.5% sugar, CO₂ production reached 4.71% at the 72nd h of fermentation. However, it was observed that limonene, cineol, and linalool, which are characteristic terpenes of hazelnut, were partially preserved during fermentation. In conclusion, using a sustainable byproduct, such as hazelnut meal, in water kefir production yields a potentially probiotic beverage with high nutritional value and desirable aroma-related characteristics.