Quality and microstructure of freeze-dried yoghurt fortified with additives as protective agents

Abstract

The effect of freeze drying of yoghurt and addition of some additives on the physico-chemical, microbiological, texture, microstructure, and sensory quality of yoghurt was studied. Freeze drying of yoghurt had light effects on the viability of Streptococcus thermophilus and no effect on viability of Lactobacillus delbreuckii subsp. bulgaricus and rehydrated yoghurt. Addition of modified starch had a considerable protection effect on Streptococcus thermophilus during freeze drying process. Addition of whey protein concentrate produced different surface structures and caused porous and loos structure. The microstructure of the freeze-dried yoghurt fortified with spirulina powder showed a coarse and a compact less porous structure in comparison with the freeze-dried yoghurt samples fortified with whey protein concentrate. All Additives significantly decreased adhesiveness and significantly increased cohesiveness, springiness, gumminess, and chewiness in both fresh and rehydrated yoghurts.

Freeze-Dried Tuna Pepsin Powder Stabilized by Some Cryoprotectants: In Vitro Simulated Gastric Digestion toward Different Proteins and Its Storage Stability

“…However, Caparino et al [ 25 ] reported that the freeze-dried mango powder appeared as smooth flakes. Ismail et al [ 26 ] prepared freeze-dried yogurt with the addition of some additives (spirulina powder, modified starch, and whey protein concentrate). After completing freeze-drying, the resultant product had a flake-like structure.…”

Functional, Rheological and Microstructural Properties of Freeze-Dried Yoghurt Powder

“…Tontul et al (2018) found the moisture content of freezedried yoghurt as 8.3%. Ismail et al (2020) could manufacture freeze-dried yoghurt powder with no additive having 4.25%.…”

“…There are several researches on yoghurt powder production by using different drying techniques, either applying more than one or only one technique, such as spray drying, freeze drying, refractance window drying and air drying (Koç et al, 2014;Zungur-Bastıoğlu et al, 2016;Carvalho et al, 2017;Fournaise et al, 2020;Ismail et al, 2020;Monsalve-Atencio et al, 2021). Freeze drying is applied to extend the shelf life in which the quality of the reconstituted product remains unchanged.…”

Enkapsulasi Pediococcus pentosaceus Menggunakan Matriks Kombinasi Tapioka Asam dan Tapioka nanokristalin dengan Susu Skim

“…Pati merupakan polisakarida dengan kandungan molekul amilosa dan amilopektin pada strukturnya. Ismail et al (2020) menyatakan bahwa penambahan pati termodifikasi memberikan efek perlindungan terhadap sel Streptococcus thermophilus selama freeze drying. Charles et al (2021) juga menemukan bahwa kombinasi bahan penyalut dengan pati garut pada enkapsulasi menggunakan freeze drying menunjukkan hasil stabilitas oksidasi terbaik selama penyimpanan 90 hari.…”