Exploration of Foods and Foodomics

Table 2. Viable count (log CFU/g) of starter bacteria in bio-yogurt supplemented with threonine (0, 1, 5, and 10 mg/100 mL of milk) during a 21-day storage period.

Starter bacteria count log CFU/g	Threonine (mg/100 mL of milk)	Storage periods (days)
Starter bacteria count log CFU/g	Threonine (mg/100 mL of milk)	1	7	14	21
Bb-12	0	8.55^a ± 0.15	8.72^a ± 0.29	7.22^a ± 0.30	7.01^a ± 0.55
	1	8.58^a ± 0.21	8.81^a ± 0.41	7.22^a ± 0.22	7.01^a ± 0.46
	5	8.58^a ± 0.36	8.80^a ± 0.26	7.24^a ± 0.51	7.02^a ± 0.31
	10	8.57^a ± 0.33	8.80^a ± 0.25	7.25^a ± 0.19	7.03^a ± 0.29
La-5	0	8.33^a ± 0.22	8.47^a ± 0.18	8.05^a ± 0.25	7.52^a ± 0.14
	1	8.33^a ± 0.25	8.45^a ± 0.31	8.03^a ± 0.11	7.52^a ± 0.32
	5	8.34^a ± 0.29	8.44^a ± 0.46	8.00^a ± 0.21	7.55^a ± 0.23
	10	8.34^a ± 0.18	8.42^a ± 0.51	8.00^a ± 0.26	7.56^a ± 0.21
ST	0	8.53^a ± 0.72	8.71^a ± 0.10	8.22^a ± 0.24	7.82^a ± 0.16
	1	8.56^a ± 0.49	8.75^a ± 0.22	8.23^a ± 0.21	7.89^a ± 0.23
	5	8.55^a ± 0.55	8.76^a ± 0.49	8.25^a ± 0.34	7.85^a ± 0.21
	10	8.57^a ± 0.62	8.77^a ± 0.33	8.26^a ± 0.28	7.88^a ± 0.11

Return to article view

a, b, c: different letters in columns indicate significant differences at p < 0.05.

Declarations

Author contributions

STGAS: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Visualization, Project administration, Writing—original draft. AKN: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Visualization, Supervision, Validation, Writing—original draft, Writing—review & editing. Both authors read and approved the submitted version.

Conflicts of interest

The authors declare that they have no conflicts of interest.

Ethical approval

The study involved a standardized sensory evaluation of food products, and informed consent was obtained from all participants before testing. The protocol posed no health risks, and the Food Science department/University of Basrah exempted the study from formal ethical approval. Sensory assessment was conducted in accordance with the ethical principles of the Declaration of Helsinki.

Consent to participate

Informed consent was obtained from all participants to participate in the sensory assessment in the study.

Consent to publication

Not applicable.

Availability of data and materials

The raw data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation, to any qualified researcher.

Funding

The authors received no funding to complete this study.

Copyright

Publisher’s note

Open Exploration maintains a neutral stance on jurisdictional claims in published institutional affiliations and maps. All opinions expressed in this article are the personal views of the author(s) and do not represent the stance of the editorial team or the publisher.

References

Hoxha R, Evstatieva Y, Nikolova D. Physicochemical, Rheological, and Sensory Characteristics of Yogurt Fermented by Lactic Acid Bacteria with Probiotic Potential and Bioprotective Properties. Foods. 2023;12:2552. [DOI] [PubMed] [PMC]

Al-Sahlany STG, Khassaf WH, Niamah AK, Abd Al-Manhel AJ. Date juice addition to bio-yogurt: The effects on physicochemical and microbiological properties during storage, as well as blood parameters in vivo. J Saudi Soc Agric Sci. 2023;22:71–7. [DOI]

Huang Y, Yu J, Zhou Q, Sun L, Liu D, Liang M. Preparation of yogurt-flavored bases by mixed lactic acid bacteria with the addition of lipase. LWT. 2020;131:109577. [DOI]

Gwak JH, Choi YJ, Ayub H, Seol MK, Kim H, Jung MY. Comprehensive genomic and functional analysis of Leuconostoc lactic acid bacteria in alcohol and acetaldehyde metabolism. J Microbiol. 2025;63:e2410026. [DOI] [PubMed] [PMC]

Al-Zobaay WJ, Al-Zobaay AH. Enhance of Flavor and Some Microbial, Physiochemical and Sensory Properties of Yogurt by Threonine and Glycine. Diyala Agric Sci J. 2022;14:85–94. [DOI]

Zourari A, Accolas JP, Desmazeaud MJ. Metabolism and biochemical characteristics of yogurt bacteria. A review. Lait. 1992;72:1–34. [DOI]

Nijdam J, Torrico D, Breitmeyer J, Hider R, Kumar L, Chelikani V. Quantification of key aromatic compounds in plant-based yoghurt alternatives and dairy yoghurts produced using different starter cultures and citric acid and threonine supplements. J Food Compos Anal. 2025;144:107711. [DOI]

Niamah AK, Al-Sahlany STG, Al-Manhel AJ. Gum Arabic uses as prebiotic in yogurt production and study effects on physical, chemical properties and survivability of probiotic bacteria during cold storage. World Appl Sci J. 2016;34:1190–6. [DOI]

Korkmaz IO, Bilici C, Korkmaz S. Sensory, pH, synaeresis, water-holding capacity, and microbiological changes in homemade yogurt prepared with maca (Lepidium meyenii) powder and propolis extract. Int J Gastronomy Food Sci. 2021;23:100291. [DOI]

10.

Jaafar FE, Rubaiy HHMA, Niamah AK. Effect of Different Air Oven Temperatures on Chemical, Physical, and Microbial Properties of Dried Bio-Yoghurt Product. Dairy. 2024;5:44–53. [DOI]

11.

Akyol I, Serdaroglu K, Gezginc Y, Dayisoylu KS, Ekinci MS, Ozkose E. Redirection of Pyruvate Pathway of Lactic Acid Bacteria to Improve Cheese Quality. Food Biotechnol. 2009;23:200–13. [DOI]

12.

Sharif MK, Butt MS, Sharif HR, Nasir M. Sensory evaluation and consumer acceptability. In: Khan IA, Farooq M, editors. Handbook of food science and technology. University of Agriculture: Faisalabad, Pakistan; 2017. pp. 361–86.

13.

Niamah AK, Al-fekaiki DF, Al-Sahlany STG, Verma DK, Patel AR, Singh S. Investigating the effect of addition of probiotic microorganisms (bacteria or yeast) to yoghurt on the viability and volatile aromatic profiles. J Food Meas Charact. 2023;17:5463–73. [DOI]

14.

Özer B, Atasoy F. Effect of addition of amino acids, treatment with β-galactosidase and use of heat-shocked cultures on the acetaldehyde level in yoghurt. Int J Dairy Technol. 2002;55:166–70. [DOI]

15.

Lucey JA. Formation and Physical Properties of Milk Protein Gels. J Dairy Sci. 2002;85:281–94. [DOI] [PubMed]

16.

Gao J, Li X, Zhang G, Sadiq FA, Simal-Gandara J, Xiao J, et al. Probiotics in the dairy industry—Advances and opportunities. Compr Rev Food Sci Food Saf. 2021;20:3937–82. [DOI] [PubMed]

17.

Cui L, Chang SK, Nannapaneni R. Comparative studies on the effect of probiotic additions on the physicochemical and microbiological properties of yoghurt made from soymilk and cow's milk during refrigeration storage (R2). Food Control. 2021;119:107474. [DOI]

18.

Meybodi NM, Mortazavian AM, Arab M, Nematollahi A. Probiotic viability in yoghurt: A review of influential factors. Int Dairy J. 2020;109:104793. [DOI]

19.

Saccaro DM, Tamime AY, Pilleggi ALO, Oliveira MN. The viability of three probiotic organisms grown with yoghurt starter cultures during storage for 21 days at 4°C. Int J Dairy Technol. 2009;62:397–404. [DOI]

20.

Ziarno M, Zaręba D, Ścibisz I, Kozłowska M. Comprehensive studies on the stability of yogurt-type fermented soy beverages during refrigerated storage using dairy starter cultures. Front Microbiol. 2023;14:1230025. [DOI] [PubMed] [PMC]

21.

Xu J, Guo L, Zhao N, Meng X, Zhang J, Wang T, et al. Response mechanisms to acid stress of acid-resistant bacteria and biotechnological applications in the food industry. Crit Rev Biotechnol. 20223;43:258–74. [DOI] [PubMed]

22.

Tripathi M, Giri S. Probiotic functional foods: Survival of probiotics during processing and storage. J Funct Foods. 2014;9:225–41. [DOI]

23.

Cheng H. Volatile Flavor Compounds in Yogurt: A Review. Crit Rev Food Sci Nutr. 2010;50:938–50. [DOI] [PubMed]

24.

Krastanov A, Georgiev M, Slavchev A, Blazheva D, Goranov B, Ibrahim SA. Design and Volatile Compound Profiling of Starter Cultures for Yogurt Preparation. Foods. 2023;12:379. [DOI] [PubMed] [PMC]

25.

Forss DA. Mechanisms of formation of aroma compounds in milk and milk products. J Dairy Res. 1979;46:691–706. [DOI]

26.

Tong D, Xia C, Hua BQ, Jun LW, Chao ZJ, Ping ZH. Effect ofl-Threonine Concentrations on Acetaldehyde Production andglyAGene Expression in Fermented Milk by Streptococcus thermophilus. Food Biotechnol. 2012;26:280–92. [DOI]

27.

Marranzini RM, Schmidt RH, Shireman RB, Marshall MR, Cornell JA. Effect of Threonine and Glycine Concentrations on Threonine Aldolase Activity of Yogurt Microorganisms During Growth in a Modified Milk Prepared by Ultrafiltration. J Dairy Sci. 1989;72:1142–8. [DOI] [PubMed]

28.

Dan T, Wang D, Jin RL, Zhang HP, Zhou TT, Sun TS. Characterization of volatile compounds in fermented milk using solid-phase microextraction methods coupled with gas chromatography-mass spectrometry. J Dairy Sci. 2017;100:2488–500. [DOI] [PubMed]

29.

Dan T, Wang D, Wu S, Jin R, Ren W, Sun T. Profiles of Volatile Flavor Compounds in Milk Fermented with Different Proportional Combinations of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Molecules. 2017;22:1633. [DOI] [PubMed] [PMC]

30.

Sfakianakis P, Tzia C. Conventional and Innovative Processing of Milk for Yogurt Manufacture; Development of Texture and Flavor: A Review. Foods. 2014;3:176–93. [DOI] [PubMed] [PMC]

31.

Mora-Villalobos JA, Montero-Zamora J, Barboza N, Rojas-Garbanzo C, Usaga J, Redondo-Solano M, et al. Multi-Product Lactic Acid Bacteria Fermentations: A Review. Fermentation. 2020;6:23. [DOI]

32.

Al-Sahlany ST, Niamah AK. Bacterial viability, antioxidant stability, antimutagenicity and sensory properties of onion types fermentation by using probiotic starter during storage. Nutr Food Sci. 2022;52:901–16. [DOI]

33.

Helinck S, Le Bars D, Moreau D, Yvon M. Ability of Thermophilic Lactic Acid Bacteria To Produce Aroma Compounds from Amino Acids. Appl Environ Microbiol. 2004;70:3855–61. [DOI] [PubMed] [PMC]

34.

Routray W, Mishra HN. Scientific and Technical Aspects of Yogurt Aroma and Taste: A Review. Compr Rev Food Sci Food Saf. 2011;10:208–20. [DOI]

35.

Dimitrellou D, Moschakis T, Kandylis P. Impact of Apple Pulp on Textural Characteristics, Microstructure, Volatile Profile, and Sensory Acceptance of Yogurts. Foods. 2025;14:2453. [DOI] [PubMed] [PMC]