The effect of adding olive leaves on starter culture and sensory properties of fermented Doogh

Subject Areas :

Nadia Ahmadi ¹ , Negin Ahmadi ²

1 - Department of Food and Agriculture, Standard Research Institute, Iranian National Standards Organization (INSO), Karaj, Iran
2 - Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran

Received: 2020-12-05 Accepted : 2021-04-04 Published : 2021-04-01

Keywords: Sensory Evaluation, &lt, i&gt, Streptococcus thermophiles&lt, , &lt, i&gt, Lactobacillus bulgaricus&lt, /i, Olive leaf, Doogh,

Abstract :

Doogh is considered a good carrier for the transfer of nutritious compounds, and also olive leaf is one of the nutritional requirements of experts, which can be used to enrich food products to improve human health and prevent or reduce disease. The effect of adding olive leaves before and after fermentation on pH, acidity, corrosive microorganisms, Lactobacillus bulgaricus, Streptococcus thermophilus, and sensory evaluation of the samples were evaluated. The enriched specimens were examined in the refrigerator during the 21-day storage time. The results showed that all samples enriched with different concentrations of olive leaves were acceptable and lower concentrations of treatments had more favorable sensory properties and at higher concentrations due to bitter taste and taste, the herb was diminished from sample acceptance. The number of L. bulgaricus colonies were significantly decreased during the maintenance period. The amount of this bacterium on the first day was the highest and did not have a significant effect on the Lactobacillus colonies by increasing the concentration of olive leaves. The survival of S. thermophilus in the enriched samples were not significantly different from that of the control sample and were not affected by the time and concentration of the olive leaves. Also, the addition of them in both the pre- and post-fermentation process did not have a significant effect in the number of L. bulgaricus and S. thermophilus colonies. The addition of olive leaf did not affect the viability and growth of starter microorganisms and was similar to the control sample. The microbial condition of the sample was examined for the presence of corrosive and pathogenic microorganisms during the storage of 21 days in a refrigerator. The addition of olive leaves before and after the process did not affect the microbial status of the sample.

References:

1. Rahmanian N, Jafari SM, Wani TA. Bioactive profile, dehydration, extraction and application of the bioactive components of olive leaves. Trends in Food Science & Technology. 2015;42(2):150-72.


2. Keramatjou E, Hesari J, Azadmard, S, Peighambardoust, SH, Nemati, M. Antioxidant effect of olive leaf on stability of butter. Journal of Food Processing and Preservation. 2013;5(1):81-94.


3. Mortazavi A, Qhods Rohani M, Joyandeh, H. Technology of milk and dairy products. Ferdowsi University Press. ISBN:964-5782-47-3. NO.185. 1995.


4. Lee KG, Shibamoto T. Determination of antioxidant potential of volatile extracts isolated from various herbs and spices. Journal of Agricultural and Food Chemistry. 2002;50(17):4947-52.


5. Iranian National Standards No.2406. Microbiology of milk and milk products – specifications and test methods. Institute of Standards and Industrial Research of Iran; 2016. [in Persian].


6. Iranian National Standards No.2852. Determination of acidity titratable and potentiometric pH in milk and milk products. Institute of Standards and Industrial Research of Iran; 2006. [in Persian].


7. Iranian National Standards No.4940. Method for sensory evaluation of fermented milk products. Institute of Standards and Industrial Research of Iran; 1998. [in Persian].


8. Iranian National Standards No.5234. Milk and Milk Products-Enumeration of Presumptive Escherichia coli-Most probable number (MPN). Institute of Standards and Industrial Research of Iran; 2015. [in Persian].


9. Iranian National Standards No.6806-1. Microbiology of food and animal feeding stuffs – enumeration of coagulase-positive staphylococci (Staphylococcus aureus and other species) – test method; part1: techniques using Baird – parker agar medium. Institute of Standards and Industrial Research of Iran; 2003. [in Persian].


10. Iranian National Standards No.7714. Yogurt –Enumeration of characteristic microorganisms -Colony count technique at 37 ˚C. Institute of Standards and Industrial Research of Iran; 2004. [in Persian].


11. Iranian National Standards No.10154. Milk and milk products – Enumeration of colony-forming units of yeasts and/or molds-colony - Count technique at 25˚C. Institute of Standards and Industrial Research of Iran; 2007. [in Persian].


12. Iranian National Standards No.13965. sensory analysis –methodology – general guidance for measuring odor, flavor, and taste detection thresholds by a three-alternative forced-choice (3-AFC) procedure. Institute of Standards and Industrial Research of Iran; 2020. [in Persian].


13. Iranian National Standards No.4691. The general method for sensory evaluation of dairy products. Institute of Standards and Industrial Research of Iran; 1999. [in Persian].


14. Zoidou E, Magiatis P, Melliou E, Constantinou M, Haroutounian S, Skaltsounis AL. Oleuropein as a bioactive constituent added in milk and yogurt. Food chemistry. 2014 Sep 1;158:319-24.


15. Marhamatizadeh MH, Ehsandoost E, Gholami P, Mohaghegh MD. Effect of olive leaf extract on growth and viability of Lactobacillus acidophilus and Bifidobacterium bifidum for production of probiotic milk and yoghurt. International Journal of Farming and Allied Sciences. 2013;2(17):572-8.


16. Amirdivani S, Baba AS. Changes in yogurt fermentation characteristics, and antioxidant potential and in vitro inhibition of angiotensin-1 converting enzyme upon the inclusion of peppermint, dill and basil. LWT-Food Science and Technology. 2011;44(6):1458-64.


17. Nontasan S, Moongngarm A, Deeseenthum S. Application of functional colorant prepared from black rice bran in yogurt. APCBEE Procedia. 2012;2,62-7.


18. Oliveira A, Alexandre EM, Coelho M, Lopes C, Almeida DP, Pintado M. Incorporation of strawberries preparation in yoghurt: Impact on phytochemicals and milk proteins. Food Chemistry. 2015;171,370-8.


19. Illupapalayam VV, Smith SC, Gamlath S. Consumer acceptability and antioxidant potential of probiotic-yogurt with spices. LWT-Food Science and Technology. 2014;55(1):255-62.


20. Zainoldin KH, Baba AS. The effect of Hylocereus polyrhizus and Hylocereus undatus on physicochemical, proteolysis, and antioxidant activity in yogurt. World Academy of Science, Engineering and Technology. 2009;60,361-6.


21. Jaziri I, Slama MB, Mhadhbi H, Urdaci MC, Hamdi M. Effect of green and black teas (Camellia sinensis L.) on the characteristic microflora of yogurt during fermentation and refrigerated storage. Food Chemistry. 2009;112(3):614-20.


22. Bertolino M, Belviso S, Dal Bello B, Ghirardello D, Giordano M, Rolle L, Gerbi V, Zeppa G. Influence of the addition of different hazelnut skins on the physicochemical, antioxidant, polyphenol and sensory properties of yogurt. LWT-Food Science and Technology. 2015;63(2):1145-54.