Fermentation study finds 'super' potential in rice wine by-product

Filipino researchers could have found a way to optimise the traditional procedure for making Philippine rice wine or ‘tapuy’ to produce a potential superfood rich in anti-aging compounds and antioxidants.

Edward Kevin B. Bragais from the Ateneo de Manila University and Paul Mark B. Medina from the University of the Philippines studied the effects of different starter cultures — that is, the specific set of microorganisms used to jumpstart the fermentation process, locally called ‘bubod’ — on the solid leftovers from winemaking. These often discarded remnants, called ‘lees’, are mostly made up of rice residues, yeast and other microbial by-products.

The researchers found that by optimising the fermentation process with a well-defined microbial culture, tapuy lees could become a valuable source of natural compounds with potential medical and nutritional benefits.

Tapuy starts out as a mixture of black and white glutinous rice (A), which is fermented using a starter culture or bubod.  After a month, the solid residues from the fermentation process or lees (B) are filtered out and usually discarded. Image credit: Bragais and Medina, 2025

Tapuy lees made using an optimised starter culture mix were found to contain high levels of polyphenols — compounds known for their ability to fight oxidative stress, inflammation and cell damage.

The researchers have tested the by-product on animals and the results suggest that tapuy lees could have potential if repurposed as a health food. 

The researchers will now need to conduct clinical trials to further explore the human potential.

The findings have been published in the journal Discover Food.

Top image credit: iStock.com/YinYang