Food Grade Ethanol
Food grade reagents are chemicals that can be added directly to food without rendering it unsafe for consumption. Food grade chemicals often are involved in processing without being present in the final product, either because they were removed or transformed via chemical reaction. In many cases, the food grade chemical remains, untransformed, in the final product, within a specified dosage limit. For example, ethanol could be used as a carrier for flavor or emulsifying compounds, but may be removed via evaporation from the final product. It is still essential to use food grade ethanol to eliminate the risk of unsafe impurities remaining in the food. Alternatively, ethanol can remain untransformed in the final product, since it is the only straight-carbon chain alcohol (i.e. methanol, ethanol, propanol, butanol, etc.) that can be metabolized in the human body.
Ethanol can be produced via synthesis, or via fermentation of sugar. Food grade ethanol is obtained via the latter process, and comprises less than one-tenth of total bioethanol production in the US. Any plant that can be broken down into simple sugars is a plausible substrate for ethanol fermentation. In the US, corn is easily our most abundant crop. Corn is a starch, a complex carbohydrate, and does not readily enter the fermentation without pre-treatment. Careful pre-treatment minimizes the byproducts produced during fermentation, so that fewer additional purification steps are required post-fermentation. First, the starch is separated from the other components of the corn via wet-milling. The starch is then treated enzymatically to break down the starch into smaller saccharides, which can be fermented via inoculation with food grade yeast. Yeast has a relatively low tolerance for ethanol, and die off as concentrations rise. The fermentation product must then be distilled to remove water and other organic impurities. The maximum ethanol concentration that can be achieved via distillation is 95.6%, because water and ethanol form an azeotropic mixture with a boiling point that is lower than the boiling point of either chemical in isolation. Moreover, many of the impurities present share a similar boiling point and cannot be removed during distillation either. Subsequent purification techniques usually include treatment with adsorbents such as activated carbon. This removes the remaining water and organic impurities.
Ethanol fulfils a variety of roles in food applications. It may be used as a carrier for flavor extracts or coloring additives, as an antimicrobial agent, and as a flavor enhancer, just to name a few. Ethanol emitters are an example of active packaging used to inhibit mold-growth in bread. From a research standpoint, it is useful as a solvent for chromatography and other separation or extraction methods. The quality of the ethanol is important for not only the safety of the food in question, but the quality, since impure ethanol can contain volatile organic compounds (VOCs) that impart negative odors even at trace levels.
The purity of food grade ethanol is stipulated by the FCC (Food Chemical Codex), under the jurisdiction of the USP (US Pharmacopeia). Organic regulations and certification are controlled by the USDA. Even plant-derived products like bioethanol are not guaranteed vegan, since they could still involve non-vegan processing aids like bone char – an adsorbent material similar to activated charcoal that is commonly used during sugar refinement. High purity food grade ethanol is essential for many analytical and chemical synthesis applications.
Ethanol has old roots in our food system – roots that far pre-date the ability to distill ethanol to ultra-high purity. As such, ethanol has diverse roles in food processing even at concentrations of 70% and lower. The continued use of the term “proof” is a testament to the long-standing use of ethanol in our culture. Proof measurement units derive from outdated methods of testing for alcohol content. If gunpowder soaked in alcohol would still ignite, the alcohol was classified as “above proof” and taxed accordingly. If the soaked gunpowder would not ignite, it signified that potassium nitrate (a compound in gunpowder) had dissolved in the high water concentration. “Above proof” generally meant that the alcohol was above 57%. Today “proof” is not used at all in many countries. In the US, it is defined as twice the alcohol by volume (ABV), but this conversion is not consistent internationally.
Food grade ethanol, 140 proof, can be used for hand sanitizers and to sanitize surfaces that come into contact with food. 70% ABV is the optimal concentration for ethanol to function as an antibacterial or antimicrobial agent, since this is the concentration that facilitates protein denaturation. This principal should also be applied to the use of ethanol as a preservative in food, including bread products to inhibit the growth of yeasts and molds. 70% ethanol can also be used to extract botanicals for common kitchen flavor extracts like vanilla, almond, or anise, as well as less common flavor palettes for use in food product development. Alternatively, it can be used to remove unwanted off-aromas, as with plant-derived protein powders. Ethanol is a common carrier for flavor manipulation or flavor enhancement, since it solubilizes most flavor compounds and is easily removed via evaporation.< Back