The effect of different lyophilisation pressures on the microbiological stability, physicochemical, microstructural, and sensorial properties of yoghurt powders

Öztürk H. İ.

International Dairy Journal, cilt.129, 2022 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 129
  • Basım Tarihi: 2022
  • Doi Numarası: 10.1016/j.idairyj.2022.105347
  • Dergi Adı: International Dairy Journal
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Food Science & Technology Abstracts, Veterinary Science Database
  • Yıldız Teknik Üniversitesi Adresli: Hayır

Özet

This study investigated how different pressures used in the lyophilisation process affected the physicochemical, microstructural, microbiological, and sensory properties of yoghurt powders. To that end, pressures of 0.3 (0.3PY), 0.5 (0.5PY) and 1.0 (1.0PY) mbar were applied to obtain powders. Additionally, some physical and sensory properties of rehydrated yoghurt powders were evaluated. Different pressures did not affect final moisture content and powder yield. According to CLSM examinations, 0.3PY showed finer protein network, while the formation of coarser protein clusters in 0.5PY and 1.0PY was noted. Water activity of powders increased with increasing pressure. The count of Lactobacillus bulgaricus was higher in 0.5PY and 1.0PY, while Streptococcus thermophilus showed 93–95% viability. WHC and viscosity values of all rehydrated yoghurts were found to be considerably lower than fresh yoghurts; however, the best results related to these properties were determined in reconstituted yoghurts of 0.5PY and 1.0PY.