Utilisation of yoghurt bacteria and probiotic combination enhanced melatonin content and antioxidant activity of yoghurt

Utaida, T. and Moongngarm, A. (2024) Utilisation of yoghurt bacteria and probiotic combination enhanced melatonin content and antioxidant activity of yoghurt. International Food Research Journal (Malaysia), 31 (6). pp. 1433-1445. ISSN 2231 7546

Melatonin and its derivatives positively influence human circadian rhythms. Yoghurt is often suggested as a bedtime food because it contains tryptophan which can be converted to melatonin. However, the impact of yoghurt bacteria (YC) and probiotics on producing melatonin and its derivative content in yoghurt during fermentation has not yet been reported. Therefore, the present work investigated the effect of YC and probiotics on enhancing tryptophan, serotonin, and melatonin during yoghurt fermentation. Cow milk yoghurt was prepared using different combinations of YC (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, MP-YC, control); YC and Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis (MP-BY); S. thermophiles, L. acidophilus, and B. animalis subsp. lactis (MP-BT); and YC with L. acidophilus (MPLA). Combining YC and probiotic mixtures had no impact on pH and total acidity after fermentation for 8 h. Yoghurt containing probiotics and YC had higher melatonin content ranging from 3.54 to 6.67 ng/g dry weight than the control, whereas serotonin was not detected. Tryptophan content significantly improved in all yoghurt samples ranging between 8.52 and 10.17 µg/g. The antioxidant activity of MP-BY and MP-BT was significantly enhanced compared with the control. The findings suggested a synergistic effect between YC and probiotics, highlighting the potential of probiotic yoghurt as a functional food rich in melatonin, tryptophan, and antioxidants, which could benefit and support human circadian rhythms and overall health.

Full text available from: Official URL: http://www.ifrj.upm.edu.my/31%20(06)%202024/05%20-...

Abstract

Melatonin and its derivatives positively influence human circadian rhythms. Yoghurt is often suggested as a bedtime food because it contains tryptophan which can be converted to melatonin. However, the impact of yoghurt bacteria (YC) and probiotics on producing melatonin and its derivative content in yoghurt during fermentation has not yet been reported. Therefore, the present work investigated the effect of YC and probiotics on enhancing tryptophan, serotonin, and melatonin during yoghurt fermentation. Cow milk yoghurt was prepared using different combinations of YC (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, MP-YC, control); YC and Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis (MP-BY); S. thermophiles, L. acidophilus, and B. animalis subsp. lactis (MP-BT); and YC with L. acidophilus (MPLA). Combining YC and probiotic mixtures had no impact on pH and total acidity after fermentation for 8 h. Yoghurt containing probiotics and YC had higher melatonin content ranging from 3.54 to 6.67 ng/g dry weight than the control, whereas serotonin was not detected. Tryptophan content significantly improved in all yoghurt samples ranging between 8.52 and 10.17 µg/g. The antioxidant activity of MP-BY and MP-BT was significantly enhanced compared with the control. The findings suggested a synergistic effect between YC and probiotics, highlighting the potential of probiotic yoghurt as a functional food rich in melatonin, tryptophan, and antioxidants, which could benefit and support human circadian rhythms and overall health.

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Item Type:	Article
AGROVOC Term:	yoghurt
AGROVOC Term:	cow milk
AGROVOC Term:	functional foods
AGROVOC Term:	serotonin
AGROVOC Term:	fermentation
AGROVOC Term:	food production
AGROVOC Term:	probiotics
AGROVOC Term:	Lactobacillus acidophilus
AGROVOC Term:	Streptococcus thermophilus
AGROVOC Term:	Lactobacillus delbrueckii
Geographical Term:	Thailand
Uncontrolled Keywords:	bioactive compound, circadian rhythm, functional food, Lactobacillus acidophilus, probiotic
Depositing User:	Nor Hasnita Abdul Samat
Date Deposited:	07 May 2026 04:39
Last Modified:	07 May 2026 04:39
URI:	http://webagris.upm.edu.my/id/eprint/4056

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