Lactic acid fermentation have been reported to increase the antioxidant activity in some herbal teas. Also fermentation process has been known to increase the nutritional aspect and bio activity in fruits and vegetables.

http://www.ifrj.upm.edu.my/21%20(04)%202014/30%20IFRJ%2021%20(04)%202014%20Ibrahim%20013.pdf

Article The effect of heating and fermenting on antioxidant properti...

Article Effect of fermentation on the antioxidant activity in plant-...

Thanks Mrs. Sonika Singh for your information

Dear Wawan,

In Ayurveda the traditional medicine of India,many different herbal juices are fermented with both acidic fermentation and alcoholic fermentation.They possess many properties from antioxidant,antimicrobial,anti-inflammatory and many others.Following references might be of help.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3326893/

http://www.ijrap.net/admin/php/uploads/1426_pdf.pdf

Regards

Dr Jyoti B Gavali

Fermentation process definitely add functional value to herbal juice or decoction.  Specific bioactives come into play and initiate various changes in the formulation. also refer to the articles attached below.

Article 'Ashvagandharishta' prepared using yeast consortium from W. ...

Article "Ayurvedic hydro-alcoholic anti-asthmatic medicine Vasarisht...

Dear Wawan,

fermentation of fruit juices certainly can certainly enhance the functional qualities of fruit juices. Depending on the microbe involved in the process and the secondary metabolites produced by the activity of the relevant organism quality may vary. And there can also be interactions with fruit sugars and organic acids as well as phenolic components of the juice and these components may have beneficial interactions with the microbial by products. Ageing of wine makes it more palatable.