Bioprocessing of food substrates by dietary microorganisms is a promising strategy for the production of phenolicenriched foods and food ingredients. Knowledge of the
processes that occur during bioprocessing is important to
facilitate optimization of the strategy for specific substrates.
Previously, lignin or polymeric phenolic degradation
activities were linked to phenolic antioxidant mobilization
from soybean substrate during solid-state bioprocessing by
dietary fungi [15]. Here, we investigated the involvement of
lignin-like degradation activities during soymilk yogurt
production via bioprocessing by active Kefir cultures.
Phenolic mobilization was associated with total peroxidase,
laccase, and b-glucosidase activities, three activities
normally associated with lignin or polymeric phenolic
degradation. Previously, a model for phenolic antioxidant
mobilization from soybean during solid-state bioprocessing
by dietary fungi, which linked a flux between the formation/
degradation of polymeric (lignin-like) phenolics and the
liberation of free phenolics was hypothesized [15]. The
results here further suggest that a similar model/mechanism
may occur during phenolic antioxidant mobilization from
soymilk during bioprocessing by active Kefir cultures, a
natural yogurt production strategy. In light of the numerous
health benefits that have been linked to the consumption
of soy products and related soybean phenolics, the observation of increased phenolic content in soymilk yogurt is
encouraging and will be further investigated in relation to
potential health-promoting activities of soymilk yogurt.