NHDC was discovered during the 1960s as part of a United States Department of Agriculture research program to find methods for minimizing the taste of bitter flavorants in citrus juices. Neohesperidin is one such bitter compound. When treated with potassium hydroxide or another strong base, and then catalytically hydrogenated, it becomes NHDC, a compound roughly 1500-1800 times sweeter than sugar at threshold concentrations; around 340 times sweeter than sugar weight-for-weight. Its potency is naturally affected by such factors as the application it is used for, and the pH of the product.
Like other highly sweet glycosides, such as glycyrrhizin (from the licorice root) and those found in stevia, NHDC's sweet taste has a slower onset than sugar's and lingers in the mouth for some time. Unlike aspartame, NHDC is stable to elevated temperatures and to acidic or basic conditions, and so can be used in applications that require a long shelf life. NHDC itself can stay foodsafe for up to five years when stored in optimal conditions.
The European Union approved NHDC's use as a sweetener in 1994. It has not been approved as a sweetener in the United States. It is sometimes said that NHDC is considered a Generally Recognized as Safe flavour enhancer by the Flavour and Extract Manufacturers' Association, which is a trade group with no legal standing. NHDC has never appeared on the FDA's GRAS listing.
It is particularly effective in masking the bitter tastes of other compounds found in citrus, including limonin and naringin. Industrially, it is produced by extracting neohesperidin from the bitter orange, and then hydrogenating this to make NHDC.
The product is well known for having a strong synergistic effect when used in conjunction with other artificial sweeteners such as aspartame, saccharin, acesulfame potassium, and cyclamate, as well as sugar alcohols such as xylitol. NHDC usage boosts the effects of these sweeteners at lower concentrations than would otherwise be required; smaller amounts of other sweeteners are needed. This provides a cost benefit.
As a flavour enhancer, NHDC is used in a wide range of products and is indicated by the E number E 959. It is noted particularly for enhancing sensory effects (known in the industry as 'mouth feel.') An example of this is 'creaminess' in dairy foods such as yogurt and ice cream but is also widely favoured for use in otherwise naturally bitter products. Pharmaceutical companies are fond of the product as a means of reducing the bitterness of pharmacological drugs in tablet form and it has been used for livestock feed as a means of reducing feeding time. Other products NHDC can be found in may include a wide variety of alcoholic beverages (and non-alcoholic), savoury foods, toothpaste, mouthwash and condiments such as ketchup and mayonnaise.
NHDC in pure form is found as a white substance not unlike powdered sugar. In food it is used as a flavour enhancer in concentrations of around 4-5 parts per million (ppm) and as an artificial sweetener at around 15-20 ppm.
Research has shown that at strengths of around and above 20ppm, NHDC can produce side effects such as nausea and migraine. This is not widely documented, however is unquestionably known within the food science communities that have worked with the product, and many recommend wearing a surgical mask when handling pure NHDC.
The Chemical Abstracts Registry Number is: 20702-77-6 The Empirical Formula is: C28