Molecularly Imprinted Polymers Help Reduce Smoke Taint in Wine

Wildfires, even when not directly hitting crops, can impart a disagreeable flavor and odor to grapes exposed to smoke, negatively affecting the wine produced. Researchers, as reported in the Journal of Agricultural and Food Chemistry, have devised a method to mitigate this smoke taint, thus enhancing the wine's palatability.

Understanding Volatile Compounds

Wine's appealing aromas and flavors derive from volatile compounds present in the grapes and produced during fermentation and aging. However, not all volatile compounds are desirable; some can make the wine smell like nail polish remover, rotten eggs, burnt rubber, or onions. Smoke from wildfires can transfer these unwanted compounds to the grapes, leading to a smoky, ashy, or medicinal taste that degrades the wine's quality.

Current Mitigation Technique Limitations

Producers currently use various adsorbents to remove undesirable compounds but often at the expense of losing essential components that define the wine's color, bouquet, and flavor. This limitation led Kerry Wilkinson and colleagues to explore the potential selective removal of smoke taint using molecularly imprinted polymers (MIPs).

The Role of Molecularly Imprinted Polymers (MIPs)

MIPs are synthetic materials designed to bind to specific target compounds selectively. The researchers' goal was to utilize these polymers to extract the smoky substances from the wine while preserving its essential sensory and visual attributes.

Experimentation and Results

The research team introduced MIP beads, either enclosed in muslin or mesh bags or freely floating in the liquid. Chemical analysis and taste tests, conducted by experts, the general public, students, and staff, evaluated the results. In some experiments, MIPs were regenerated by rinsing post-extraction, enabling reuse.

Findings on Effectiveness

The study revealed that adding MIPs to wine post-fermentation was more effective in enhancing sensory characteristics and removing unwanted volatile phenols than adding them during fermentation. Regenerating the MIPs also improved the removal of smoky compounds. Despite adsorbing some desirable aroma, flavor, and color components, the researchers concluded that the method significantly reduces smoke taint, thereby improving wine quality.

Earlier, SSP wrote about peripheral vision: what we see in the dark.