Japanese researchers have discovered that wild grape pomace – the pulp, seeds and skin of the grape left after juicing – inhibits the primary bacteria known for causing dental caries, Streptococcus mutans.
The laboratory research, led by the Iwate Biotechnology Research Center in Kitakami, tested the Vitis coignetiae grape variety using assays together with different fractions and types of grapes. They found that the chemistry of the pomace prevented the S. mutans from forming the biofilm that enables the bacteria to attach to teeth.
This biofilm, called hydrooxyapatite, utilizes sucrose for its production – which explains why eating sugar is linked to dental caries - or cavities. The S. mutans bacteria produces this, enabling it to adhere to the surface of the tooth. Here the bacteria releases acids that eat away at tooth enamel.
The grape pomace stopped the process of the glucosyltransferases S. mutans uses to produce the biofilm allowing the bacteria to adhere to the teeth. The researchers found that greater amounts of pomace increasingly prevented bacteria adherence, in a "dose-dependent" manner.
The researchers concluded:
“The current study supports the potential of Vitis coignetiae pomace as a food additive for reducing caries by inhibiting adhesion to the tooth surface and glucosyltransferase-mediated soluble glucan synthesis.”
The pomace of grapes contain numerous polyphenols - which have independently been found to be antibacterial, anti-inflammatory and antioxidant.
The primary source of these benefits lie in the polyphenols of the grape skins. A study from the University of Chile tested four varieties of grape pomace and found significant amounts of polyphenols. These are These included proanthocyanidins. The researchers also found that white grapes contained more total polyphenols and proanthocyanidins than did the red grape pomaces.
Studies also have found that whole grapes boost the immune system, strengthen memory, help prevent cardiovascular disease and other effects.
Whole grapes contain a significant amount of vitamin K as well - some 28% of the U.S. Daily Value. They also contain good amounts of thiamin, riboflavin, folate and vitamin B6, along with copper. A serving of grapes (one cup) will also contain 1.4 grams of dietary fiber, much of which is contained within the skin.
REFERENCES:
Yano A, Kikuchi S, Takahashi T, Kohama K, Yoshida Y. Inhibitory effects of the phenolic fraction from the pomace of Vitis coignetiae on biofilm formation by Streptococcus mutans. Arch Oral Biol. 2012 Jan 25.
de la Cerda-Carrasco A, López-Solís R, Nuñez-Kalasic H, Peña-Neira A, Obreque-Slier E. Phenolic composition and antioxidant capacity of pomaces from four grape varieties (Vitis vinifera L.). J Sci Food Agric. 2014 Aug 1. doi: 10.1002/jsfa.6856.