The Effect of Probiotic on Antioxidant Activity of Phenolic Compounds in Functional Yogurt Fortified by Plum Juice

نوع المستند : المقالة الأصلية

المؤلفون

1 Home Economics Dept., Faculty of Specific Education, Fayoum University

2 Dairy Dept., Animal Production Institute, Ministry Agriculture

المستخلص

Dairy products are suitable for functional meals since they have a high nutritional value. Yogurt is remarkable with its nutritional value over the other fermented dairy products. Fermented milk products help to maintain overall gastrointestinal health. The current study aimed to investigate the fortification of yogurt made of cow’s milk and 10% plum (Prunus domestica) juice and culturing it with bifidobacterium as a probiotic along with regular culture Lactobacillus delbrueckii subsp.  bulgaricus and Streptococcus salivarius subsp. thermophilus bacteria. Physicochemical, rheological, biochemical and microbial count tests were determined during storage times of 1,7 and 14 days at 4°C. The results showed that, the yogurt fortified with Bifidobacterium and plum juice had higher acidity, total solids (T.S.), and lower pH, fat, protein and ash compared to the control yogurt. All of the chemical composition parameters of T.S., fat, protein and ash percent decreased gradually over time of storage. The addition of 10% plum juice caused the highest syneresis amount and lowest viscosity of all treatments, which varied from 16.3 ml on day 1 up to 22.2 ml on 14 days and from (149±14 Centipoise (cP) at day 1 to (70±9cP) at day 14 and affected the overall acceptability of the yogurt and overall acceptability of all of the yogurt was affected with the storage period. Ellagic acid was the predominate (28.37±0.01 μg/ml) phenolic compound in plum juice, while in control yogurt was gallic acid, chlorogenic acid in probiotic yogurt, querectin in yogurt fortified with plum juice and catechin in probiotic yogurt fortified with plum juice. However, the addition of plum juice to yogurt has enhanced its total phenolic, total flavonoid content and antioxidant activity. However; this reduced the body and texture properties of yogurt. Furthermore, the addition of plum juice into the yogurt with or without Bifidobacterium had a lower bacterial count than without it. Conclusion: The current study results have indicated that yogurt supplement with plum juice using bifidobacterium and starter culture has many health benefits especially its antioxidant activity and phenolic compounds, which have protective effects against different diseases, on the other hand, it improves yogurt quality and gives customers a variety of choices.

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