As I entered, there was no apple scent.

Part 1.
Unraveling the Secrets of Olfaction with Fragrances

1.
Why is taste so hard to describe in words?
2.
Why it's good to study incense as a fragrant substance
3.
Characteristics of the fragrant substance: strong
4.
Characteristics of fragrant substances: Stimulate multiple receptors
5.
There is no separate off-flavor substance

Part 2.
50 Fragrance Substances You Should Know

1.
terpene-based fragrant substances
Limonene: The most abundant fragrant substance we consume
Citral: Why Lemon Juice Doesn't Stay Fresh for Long
ㆍLinalool: Very common in nature, but has an unfamiliar scent when seen separately
Geraniol: A floral fragrance that is used as a raw material for perfume.
ㆍPinene: Why does the scent of pinene remind you of pine trees?
Menthol: Why peppermint candy feels cool
ㆍL-Carbon: Mirror isomer, produces a completely different scent when the left and right sides are swapped
Camphor: The scent of camphor that awakens the brain
Eucalyptol: Why Koalas Only Sleep
Terpinene: Foods can change the color or smell of urine.
ㆍCatnip: Mosquitoes drive even lions crazy.
ㆍPara-Simen: Why does minari sometimes smell like gasoline?
Caryophyllene: How did pepper paralyze European society?
Geosmin: The soil itself has no odor.
ㆍIonone: The allure of ionone that shook up the perfume industry
ㆍDamascenone: A special fragrant substance that gives different feelings to each person.

2.
Aromatic fragrance substances
ㆍPhenylacetaldehyde: The sweetness of honey is made easier than you think.
ㆍBenzyl Acetate: The fragrance of jasmine is completed through harmony.
ㆍCinnamaldehyde: Is cinnamon a food, or a medicine?
Vanillin: Why Vanilla Still the World's Second Most Expensive Spices
ㆍBenzaldehyde: An odor that suggests a poison hidden in the plant's seeds
ㆍMethyl salicylate: From plant defense signaling substance to aspirin synthesis
ㆍEugenol: How did cloves go from being one of the three major spices to smelling like a dentist?
ㆍPiperonal: A hallucinogenic substance found in nutmeg
Cresol: Why do we hate the disinfectant smell in hospitals?

3.
Carbonyl odorant
Propionic acid: The fatty acid with the most pungent odor
ㆍBeauty acid: To some it smells like putrefaction, to others it smells like blue cheese.
Acetaldehyde: Why Hangover Remedies Differ in Each Country
Diacetyl: an indicator substance for beer fermentation
Isovaleraldehyde: Why does a molecule with a branched structure have a unique smell?
ㆍTrans-2-hexanal: Grassy, ​​fresh or green, fishy smell
ㆍCis-6-Noneol: Is it really because of the smell that people dislike cucumbers?
ㆍJasmine: A modern fragrance that originated from flowers
Octenol: Fresh Mushrooms vs. Rotten Mold, Extreme Likes and Dislikes
ㆍDekanal: Please leave out the coriander!
ㆍDecadienal: Where is the boundary between meat smell and off-flavor?

4.
Esters and lactones
ㆍEthyl acetate: The main flavoring agent in alcohol, but no one knows why.
ㆍEthyl propionate: Scottish whiskey whose prestige was raised thanks to British oppression(?)
ㆍEthyl butyrate: An ester substance rich in fruity aromas
ㆍEthylhexanoate: Why it's easy to make counterfeit (?) Baekju
ㆍIsoamyl Acetate: There are no bananas in banana milk!
ㆍγ-Nonalactone, γ-Undecalactone: The Story of Lactones

5.
Incense made by heating
Furfural, 5-methylfurfural: Substances that are first formed through caramelization
Furaneol, ethylfuraneol: Various fragrant substances are commonly found in fruits.
ㆍMaltol, ethyl maltol / ㆍMaple lactone
ㆍSotolon: An odorous substance that produces a seasoning flavor
ㆍGwaycole, Siringol: No matter how much we tell them not to grill, what we want is 'smoky'.

6.
sulfur compounds
ㆍHydrogen Sulfide: What Did the Primitive Earth Smell Like?
Methyl mercaptan: Why is an odorant added to city gas?
Methional: Why Potatoes Go Well with All Kinds of Dishes
Dimethyl sulfide: Why seabirds mistake plastic for food
Truffle Sulfide: Why do truffles hide their seeds underground for reproduction?
Allyl isothiocyanate: glucosinolate and aromatic vegetables
ㆍTrisulfide: Garlic is the soul food of Koreans.
ㆍEthyl mercaptopropionate: Glutathione also significantly affects umami taste and aroma.
Furfurylthiol: The Real Reason Coffee's Flavor Is So Special
ㆍDifurfuryl disulfide: meaty aroma
ㆍSulfurol: A fragrant substance that changes into a milky or meaty scent depending on the impurities.

7.
nitrogen compounds
ㆍ2-Acetylpyridine: The flavor of rice is simpler than you think.
Dimethylpyrazine: Why Pyrazine is Important in Heated Foods
Tetramethylpyrazine: Soy sauce flavor
ㆍEmpty Pyrazine: For some, it has a healthy ginseng scent, while for others, it has the raw scent of raw potatoes.
ㆍIsobutylpyrazine: Paprika flavor
ㆍIndole: A treatment so unfair compared to the effort put into its synthesis
Ammonia: The smallest odorous substance
ㆍAcetophenone: Can wine smell like fox?
Trichloroanisole: Why even small amounts of TCA ruin the flavor of wine.
Trimethylamine: Great fishy smell

In closing
References

Taste and aroma are merely combinations of various fragrant substances.

Apples don't taste like apples.
And there is no apple scent.
You might be wondering what this means, but in reality, there is no distinct taste or aroma that can be called apple flavor from the beginning.
The only tastes we perceive from an apple are sweetness and sourness, and what we perceive as the taste of an apple is the apple scent, which is less than 0.1% of the olfactory substance.
And the scent of apples is not a special scent that only apples have, but rather a combination of various scents that exist in many other foods, just to suit apples.
There is no apple-specific flavor or aroma, so not only is there no apple taste, there is also no apple scent.


The same goes for other foods.
The aromatic substances in wine are not only found in wine, but also in other alcoholic beverages, spices, and fruits.
From the perspective of aromatic substances, apples, wine, flowers, spices, and fruits are not very different.
It is simply a different blend of the same fragrant substances.
However, there is a realistic problem that it is difficult to learn about fragrances because, except for perfumers, there are few opportunities to experience fragrant substances.
Moreover, the names of fragrant substances are often unfamiliar, and their scents are often very strong and unfamiliar.
It's not easy to come up with ideas about what individual odorants mean and how they can be used to understand olfaction and food flavor.
The need for appropriate educational programs is highlighted.

Aromatic substances are the most effective means of explaining and understanding the sense of smell.

The author of this book has written several books on taste and flavor while also giving numerous lectures.
And among them, the most responsive and highly engaged classes are those where you actually smell fragrant substances and learn about fragrances.
To understand the sense of smell, you need to understand the threshold, saturation, concentration effect, and mixing effect of fragrant substances. It is naturally more effective to learn by experiencing fragrant substances directly rather than simply explaining them in words.
Moreover, by experiencing the same fragrant substance with several people and sharing what each person felt, it had the effect of giving me a completely new perspective on my sense of smell.


The reason I chose '60 Fragrance Substances You Should Know' in this book is because knowing just this much is enough to understand fragrance and the sense of smell.
Of course, it may not be enough to fully explain the aroma of food professionally, but it is virtually impossible and unnecessary to learn and become familiar with the aroma substances of all foods.
In reality, among the hundreds of odorants found in a single food ingredient, only a few play a dominant role.
When the amount of aroma components in food ingredients is calculated and the contribution (aroma value) is analyzed by inputting a threshold, it is often the case that five or fewer aroma substances account for more than 90%.
So, it is possible for a perfumer to create a desired scent with less than 30 raw materials.
The 30 types required at this time are intended to bring out even the subtle characteristics, but the core materials are simpler.
Fragrance is the flower of food.
It can be said that dealing with taste is dealing with scent, as scent gives delicacy and variety to all foods and foods.
If you properly understand just the 60 fragrant substances in this book, it will take your knowledge of fragrance to the next level and provide an opportunity to view it comprehensively.


What is a good place to start studying fragrant substances?

The first thing that an ordinary person interested in fragrance should know when studying fragrant substances is terpene substances.
If we classify fragrant substances by origin, they can be broadly divided into terpenes, aromatics, and aliphatics. Of these, terpenes account for the largest amount and are also the most basic.
When it comes to life-related materials, it is always better to start with a large number of things.
Moreover, although terpene substances are secondary metabolites, they have their own intentionality, so their lineage can be identified by tracing the synthetic pathway.
Next are aromatic substances.
Plants (trees) create strong structures with cellulose and hemicellulose to maintain a large and strong body, and synthesize large amounts of lignin to act as an adhesive to hold them together.
And the raw material for this lignin synthesis is an amino acid called phenylalanine.
Plants produce overwhelming amounts of phenylalanine compared to other amino acids, and create several aromatic substances during the intermediate process of lignin synthesis.

If we have studied the substances produced by plant enzymes, then we need to learn about the aromatic substances produced by fermentation.
All living things require large amounts of energy (ATP) to survive.
And what is needed to produce ATP is glucose.
Complete combustion of one glucose molecule can regenerate about 30 ATP molecules.
Alcohol is the result of breaking down glucose into pyruvate and then converting it into alcohol, and respiration is the complete breakdown of glucose into carbon dioxide.
Alcoholic fermentation is ultimately the process of making large quantities of alcohol from large quantities of glucose, with some aromatic substances being produced as byproducts in the process.
Although it is a very small amount compared to alcohol, the flavor produced at this time determines the quality of the alcohol.
The intermediate process of alcohol fermentation involves organic acids, which combine with alcohol to form various esters.

If you have studied the fragrant substances made by enzymes, then you need to study the fragrant substances made by heating.
Many fragrant substances are created through caramelization, Maillard reaction, etc., but it is not easy to trace the process because they tend to be created randomly.
But most of the scents we humans like are made by heating like this.
Perhaps because cooking has played such a large role in human survival and brain development, we have a much higher sensitivity to the aromas created when cooking than other animals.
This is especially true for sulfur compounds.
So, there is a need to study sulfur compounds that affect the appeal of food, and also heat-resistant aromatic substances such as pyrazine.
The fragrant substances presented in this book may not be the best choice for studying fragrance, but it is an optimal selection filled with the most representative ones and those useful for understanding the sense of smell.
I believe that as these attempts become more diverse and the connections between aromatic substances and actual foods increase, a true understanding and exploration of our flavors will be achieved.