EFFECT OF METABOLIC REDUCTION OF PROBIOTICS ON THE FUNCTIONALITY OF FRUIT JUICE
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Date
2021-07-28
Authors
Nasser, Shaima’
Journal Title
Journal ISSN
Volume Title
Publisher
جامعة النجاح الوطنية
Abstract
Ultrasound (US) and microencapsulation can be regarded as the tools to modulate the metabolism of probiotic bacteria and, consequently, these strategies can be used to reduce the acidification of the probiotic bio-active beverages. Attenuation can be done through the combination of ultrasound (US), and microencapsulation as a physical approach. Furthermore, microencapsulation, through vibrating technology, is also aimed at incorporating probiotic strains in functional foods such as capsules with controlled release of these active strains. About attenuation, there is no data available on the effect of this treatment on the overall profile of probiotic bacteria. So, the major topics of this study: i) to study the effect of ultrasound and microencapsulation tools on the survival, acidification and growth of Limosilactobacillus reuteri DSM 17938 (L. reuteri) inoculated in tomato juice during its storage for 28 days at 4 and 20 °C, ii) to study the effect of US on L. reuteri survival at pH 2.5 and with 0.15% bile salt, iii) to get a product with chemical-physical and sensory characteristics that are acceptable to the consumers. A preliminary screening on sonication was done by using 3 power levels (57, 64 and 78 W) and two different duration time (4 and 6) min. The best combination was 57 W- 6 min; this decision come from the acceptable post-acidification and viability results after sonication. The effect of this treatment on the functional properties also studied. At low pH 2.5 L. reuteri DSM 17938 has a higher survival than the sonicated one. In contrast, the reduction of viability in case incubation in deionized sterile water containing 0.15% of bile salts of non-treated L. reuteri DSM 17938 was higher than half sonicated microorganism. The probiotication of tomato juice from market was done in three different ways (with a cell suspension, with a sonicated cell suspension and with microcapsules of the sonicated cell suspension). Post acidification and viability of L. reuteri were monitored at 4 and 20 °C for 28 days. This study confirms that the best storage temperature for L. reuteri sonicated and microencapsulated (LR-US-MC) tomato juice is 4 °C; the pH (4.13) and viability (7.24 log CFU/ml) value are higher at 4 °C storage temperature than pH (3.87) and viability (7.08 log CFU/ml) value at 20 °C