The Aromatic Scent: Unraveling The Mystery Of Aroma Smell

Aroma refers to a strong, pleasant, and distinctive smell that stimulates the olfactory system. It is often used to describe appealing scents, such as freshly brewed coffee, grilled onions, or baking bread. Aroma compounds, also known as odorants, are chemical compounds that create these scents. These compounds are found naturally in foods like fruits, spices, and wines, as well as in perfumes and essential oils. Fragrances, on the other hand, can be synthetic or natural and are commonly used in cosmetics. While the terms fragrance, scent, and aroma are sometimes used interchangeably, aroma specifically indicates a positive and appealing olfactory experience.

Aroma compounds in food and drink

Aroma compounds are chemical compounds that have a smell or odour. They are one of the main food sensory characteristics that impact consumer preference and acceptance. Aroma compounds are volatile, with molecular weights of less than 400 Da, and are present in low quantities in food. They are mostly comprised of organic molecules in a liquid or gaseous state, with a lipophilic character.

Aroma compounds can be naturally present in foods as a consequence of physiological and/or enzymatic processes, as well as generated by microorganisms during fermentation processes. They can also be produced and/or modified due to chemical, biochemical, or microbial changes during their extraction, processing, and storage, thus affecting the overall food quality, sensory profile, and shelf-life.

Aroma compounds are divided into two broad classes: those responsible for taste and those responsible for odours. Compounds responsible for taste are generally non-volatile at room temperature and interact with taste receptors in the taste buds of the tongue. Sour, sweet, bitter, and salty compounds are the four important basic taste perceptions. Glutamate stimulates the fifth basic taste.

Aroma substances, on the other hand, are volatile compounds perceived by the olfactory tissue of the nasal cavity. They can be detected through the nose (orthonasal detection) or via the throat after being released by chewing (retronasal detection).

The main classes of aroma compounds include organic acids, primary and secondary alcohols, amines and other nitrogen compounds, carbonyl compounds (aldehydes and ketones), esters, lactones, oxygen-containing heterocyclic compounds, pyrazines, and sulfur compounds.

The food industry uses aroma compounds to flavour, improve, and increase the appeal of their products.

Aroma compounds in nature

Aroma compounds are naturally present in various foods, such as fruits and their peels, wine, spices, floral scent, perfumes, fragrance oils, and essential oils. They are also known as odorants, fragrances, or flavourings. Aroma compounds are volatile molecules that can be recognised and named by our olfactory identification system.

Aroma compounds can be naturally present in foods as a consequence of physiological and/or enzymatic processes, as well as generated by microorganisms during fermentation processes. They can also be produced and/or modified due to chemical, biochemical, or microbial changes during their extraction, processing, and storage.

Aroma compounds are usually located in both the pulp and skin of fruits as free and bound glycosides. Bound glycoside forms, which can be transformed by hydrolysis into odour-active forms, are non-volatile compounds with no direct contribution to the aroma of the fruit. In contrast, free forms are volatile compounds that can be sensed and tasted directly and are involved in the aroma of the fruit.

The most important odor compound classes are organic acids, primary and secondary alcohols, volatile or non-volatile amines, carbonyl compounds, esters, lactones, and terpenes.

The difference between aroma and odour

Aroma and odour are two words that are related to the sense of smell. However, they differ in their connotations and the type of smell they describe.

Aroma is typically associated with pleasant, desirable, and appealing scents. It often describes fragrances, such as fresh flowers, spices, baked goods, coffee, or perfumes. Aromas can be created by natural sources like plants and essential oils, or synthetically through perfumes and air fresheners. They trigger positive physical and emotional responses in humans and animals.

Odour, on the other hand, usually refers to any smell, whether it is fragrant or offensive. It is often used to describe unpleasant, decaying, or spoiled scents, such as rotting garbage, sewage, dirty socks, or spoiled milk. Odours can be caused by bacteria, mould, and chemicals, and they evoke negative physical and emotional responses.

In scientific terminology, odour refers to any scent, whether pleasant or unpleasant, while aroma specifically denotes pleasant scents.

It is important to note that the choice between "aroma" and "odour" can depend on the context, personal preferences, and cultural differences. For example, in some cultures, strong smells may be considered desirable, while in others, they may be deemed offensive.

To summarise, "aroma" is generally used for pleasant smells, while "odour" can refer to any type of smell but is more commonly associated with unpleasant ones.

Aroma's effect on human health

Aromas have a profound effect on human health, both physical and mental. The olfactory system is the only sensory system with a direct link to the brain. The sense of smell is connected to the sense of taste, with up to 90% of what we taste being based on smell.

The molecules of substances, including essential oils, influence the brain and provoke a response. This was proven in 2004 when aromacology, a new special science, emerged. The inhalation of aromas affects our health, and can be used to improve our well-being. Aromatherapy, for example, uses essential oils to improve well-being, primarily through inhalation.

Aromas can have a positive effect on brain activity, stimulating mental processes and improving memory. They can also reduce anxiety and improve mood and calmness. For example, the scent of lavender has a relaxing effect, while rosemary can increase alertness.

However, fragrances can also have negative effects on health. Fragranced products often contain phthalates, which are endocrine disruptors and can be found in the blood of most Americans. They can act like hormones in the body and cause a host of health problems, including cancer, reproductive and developmental toxicity, endocrine disruption, and respiratory problems.

Aromas can also have an accumulative effect: the more frequently we breathe in an aroma, the more powerful its effect.

Aroma's role in aromatherapy

Aromas, or "pleasant smells", play a key role in aromatherapy, a holistic practice involving the inhalation or topical application of essential oils. Aromatherapy is used to treat a wide range of physical and emotional conditions, with many benefits for wellness and stress relief.

The sense of smell is one of the most powerful of our senses, with even a slight whiff of a scent able to trigger a memory. This is due to the direct link in the brain between memory and smell. The olfactory bulb, responsible for the sense of smell, is connected to the hippocampus and the amygdala, which control memory and emotions, respectively.

Essential oils are quickly absorbed by smell receptors that are linked to the limbic system, which controls heart rate, blood pressure, breathing, and stress. Each essential oil has a unique chemical makeup that affects its smell, absorption, and effect. For example, rosemary has been shown to improve mental awareness and boost energy levels, while lavender can help lower blood pressure and calm the nervous system.

Aromatherapy can be administered in several ways, including through aroma sticks, body creams, oils, or lotions, and salts for the bath. It can also be used in conjunction with massages or other spa treatments to enhance the experience and provide additional therapeutic benefits.

The use of aromas in aromatherapy allows for a personalized and tailored approach to treatment, as different combinations of aromas can be used to target specific wellness outcomes and address the unique needs of each individual. This flexibility makes aromatherapy a valuable tool in promoting physical and emotional well-being.

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