Small additions of natural raw materials can be very helpful, especially when formulating natural WONF flavors (With Other Natural Flavors). They can provide elusive, hard-to-find notes, and bring the flavor closer to an optimum level of complexity; they can also make a flavor much harder to replicate, especially if the raw materials are a little unusual or unexpected. This article lists some WONF ingredients, which in my experience are especially useful in formulations. All of them are FEMA GRAS listed, and the components listed are either present in significant quantities or contribute significantly to the odor of the raw material. Likewise, the quantities given are all typical (rather than specific), and often have wide variations in practice, even in genuine oils.
The floral, lavender note of this ingredient could be used in formulation of a wide range of flavors, especially fruit flavors. Although the presence of indole and methyl anthranilate adds to the interest in this ingredient, it simultaneously reduces the number of potential applications. However, blueberry, blackcurrant and grape flavors can easily take advantage of all the components of neroli oil, which is particularly good in these flavors. It can also be used at lower levels in orange and strawberry flavors to give an interesting twist.
Some European cookery books of the Middle Ages show that rue was a popular herb of the period. This could, perhaps, be due to taste preferences of the times, or a result of the relative absence of more interesting spices from the East. However, with changing times and tastes, this herb has declined in popularity, and today many chefs are unfamiliar with it. Nonetheless, the fruity, blue cheese note of rue is very helpful at low levels in a wide range of dairy flavors, especially in cheddar and blue cheese flavors. It is also surprisingly useful in some fruit flavors, especially pineapple.