Chemistry in daily life - tea

Tea is, like coffee, aromatic beverage and the most popular drinks in the world, which is commonly prepared by pouring hot or boiling water over cured leaves of the Camellia sinensis, an evergreen shrub native to Asia. But tea, possibly as a medicinal drink originated in China, has been consumed for thousands of years due for its elegant flavours and health benefits, in which polyphenols, flavonoids and phenolic acids, are of highly abundance and contribute a lot to its pleasant flavour and health prosperities.

Generally, tea is divided into at least six different types based on how it is processed, which are white tea (wilted and un-oxidized), yellow tea (un-wilted and un-oxidized, but allowed to yellow), green tea (un-wilted and un-oxidized), oolong tea (wilted, bruised, and partially oxidized), black tea (Chinese red tea, wilted, sometimes crushed, and fully oxidized,) and post-fermented tea (Chines black tea). But the most common ones are white, green, oolong, black and post-fermented tea.
 

Due to un-oxidized, green tea, for example, reportedly contains the highest concentration of powerful antioxidants called polyphenols, substances that fight free radicals (reactive oxygen species, ROS), which damage compounds in the body that change cells, damage DNA, and even cause cell death. There are several polyphenols in green tea, including epicatechin (EC), 2epicatechin-3-gallate (ECG),  epigallocatechin (EGC), epigallocatechin-3-gallate (EGCG),  catechin, and gallocatechin (GC), in which  EGCG is the most abundant, accounts for 65% of the total polyphenolic  content.
 

Those polyphenols have a number of health benefits and medical valuations.  High polyphenol components in green tea are reportedly believed more effective antioxidants than Vitamins C and E and to contribute to the aging process and development of a number of health problems, including cancer and heart disease. Chinese people traditionally used green tea as to help body to rid of excess fluid and  to improve body conditions, including regulating body temperature  and blood sugar, promoting digestion, and improving mental processes.

Clinical studies have suggested that antioxidant properties of green tea may help prevent atherosclerosis, particularly coronary artery disease, green tea lowers total cholesterol and raises HDL ("good") cholesterol in both animals and people and green tea may help protect against cancers, in which polyphenols is assumed to help kill cancerous cells and stop them from growing.

Many clinical studies suggest that the polyphenols in tea, especially green tea, may play an important role in the prevention of cancers, including bladder cancer, breast cancer, ovarian cancer, colorectal cancer, esophageal cancer, lung cancer, pancreatic cancer, prostate cancer, skin cancer and  stomach cancer.
 

Green tea has also been reportedly suggested  to help reduce inflammation, help prevent the development of type 1 diabetes and slow the progression once it has developed, to protect the liver from the damaging effects of toxic substances such as alcohol, help treat viral hepatitis, an inflammation of the liver, help to boost metabolism and help burn fat - combination of catechins (one of the polyphenols ) and caffeine to help body weight loss.

In addition, the metal-chelating properties of polyphenols (e.g., EGCG) are also important contributors to their protective effects (such as the iron-chelating properties of EGCG)  in neurodegenerative diseases , such as Parkinson's disease due to misregulated iron metabolism. Furthermore, polyphenols (e.g., catechin) have been reported to effects on several cellular and molecular targets in signal transduction pathways associated with cell death and cell survival (neuronal cells and in tumour epithelial/endothelial cells).

Molecular structure of EGCG.


Molecular structure of catachin, one of flavanols in green tea.

 
 

Chemistry in daily life - coffee

Coffee is a brewed drink prepared from roasted coffee beans, which are the seeds of "berries" from the Coffea plant. Coffee contains a variety of compounds. There are more than 1,000 chemical compounds detected in coffee.  Those are aliphatics, carbonyls, sulfur containing compounds, alicyclics, ketones, aromatic benzenoids, phenols, heterocyclic compound, furans, hydrofurans, pyrroles, pyridines, quinolines, pyrazines, uinoxalines, indoles, thiophens, thiophenones, thiazoles, and xazole.

 

However, the primary compound in coffee is caffeine (see the left,
Skeletal structure of a caffeine molecule), which is known for its stimulant effects. Coffee also contains the monoamine oxidase inhibitors β-carboline and harmane. Those contribute not only to the unique flavour of coffee but also to the well-researched effects of coffee on human health.

Chemistry in daily life - wine

Wine is a very complex mixture of chemical compounds in a hydro-alcoholic solution with a pH around 3 produced via a chemical reaction, in which, for example, wine made from grapes, sugars (e.g., glucose and fructose) are turned to alcohol and carbon dioxide by winemaking yeast in the presence of oxygen through the process of fermentation, an exothermic process:

                     C₆H₁₂O₆           →     2CH₃CH₂OH_(aq)   +  2CO_2(g)

Where the presence of some chemical compounds like tartaric acid, malic acid, amino acids and a few others in grapes, and many important factors determine the character of the wine produced.

Temperature control during fermentation is very important factor since heat is a catalyst, when it is applied to fermentation it speeds the bio-chemical process up. The higher the fermentation temperature the faster the yeast will convert sugars into alcohol and carbon dioxide, which sounds great

Ideal fermentation temperature for red wine should be between 20-30 ^oC.  It is important to keep temperature as reasonable lower as possible  since yeast stops growing as temperatures increase and die at higher temperatures.  .  It is, however, to keep temperature as reasonable lower as possible since yeast stops growing as temperatures increase and die at higher temperatures.  While white wine fermentation temperatures should be between 7-16 ^oC. These lower temperatures help to preserve fruitiness and volatile aromatics in wine, and have more characteristics with a white wine.

Wine chemistry explains the flavour, balance, colour, stability that was once only possible through subjective description. Understanding the principles of wine chemistry will open your eyes to a new level of wine appreciation.

The  taste of wines (or quality) is the balance of sweet, acidity and better, which come from alcohols, sugar residues (sweet taste), acidity taste (acids), and better taste (phenols).

Phenols are a class of compounds that contribute the taste, smell, medical benefits of wine and give wines their distinguishing characteristics;

Acidity of wines may be the most important aspect of wine chemistry. Interact of flavanoids and non-flavanoids derived from phenols broken down to form complicated, yet important molecules that have a profound impact on quality, colour and flavour.

Chemistry in daily life - perfume

Perfume is chemically a mixture of fragrant essential oils or aroma compounds, fixatives and solvents, in which fragrant constituents are extracted from  the leaves or flowers of plants by

● steam distillation using water steam slowly to breaks through the flowers and plant materials to extract their volatile and essential oil constituents. There are three types of distillation, including water distillation, water and steam distillation, and steam distillation include.

 ● solvent extraction using organic solvents such as petroleum ether, methanol, ethanol, or hexane to extract the odoriferous lipophilic material from the flower and plant materials.

● enfleurage using a large framed plate of glass, called a chassis, is smeared with a layer of odorless animal fats (usually from pork or beef ) that are solid (cold enfleurage) at room temperature to capture the fragrant constituents from botanical materials (usually petals or whole flowers).  In hot enfleurage, botanical matter is stirred into the fats heated t by heating extract aromatic constituents from flower and plant materials.

● maceration, or expression involving a prodding, pricking, sticking action (also referred to as cold pressing) to release the essential oil from fruits  such as tangerine, lemon, bergamot, sweet orange, and lime.

● supercritical carbon dioxide extraction using carbon dioxide that under pressure will turn from a gas into a liquid to be used as an inert liquid solvent to extract aromatic constituents from flower and plant materials.

Various organic constituents are detected , when essential oils are tested using chromatograph technique.  The main ones are given as follows:

● terpenes – representative oil: sandalwood and myrrh, huge various class of organic compounds with basic molecular formula (C₅H₈)_n which are produced by a variety of plants, particularly conifers;

● phenols -  representative oil: oregano
● alcohols - representative oil: cassia
● aldehydes - representative oil: melissa
● ketones - representative oil: peppermint
● esters - representative oil: lavender
● oxides - representative oil: eucalyptus radiate.

A perfume is composed of fragrance, aroma volatiles, alcohol (75 - 80%) and water, in which alcohol and water dissolve fragrance, the core part of perfume.  The components founded in  fragrance ingredient are the compounds, such as 2-phenyl ethanol, phenyl acetaldehyde, citronellol, civetone coumarin, linalool, amyl salicylate, isoboruyl acetate.

Perfume transfer its flavour can be divided into three stages:  1. volatile components such as: benzene, acetaldehyde (phenyl acetaldehyde), quickly reach the nose, causing a first impression,  2. the main components of perfume smell, such as benzene, ethanol (2-phenyl ethanol) (with rose flavour) and nose effect, 3. the lasting ingredients, such as: civet ketone (civetone) with a musky smell.

Chemistry in daily life - sunscreens

Sunscreen, also commonly known as sunblock, or sunburn cream, is a lotion that absorbs or reflects some of the sun’s ultraviolet (UV) radiation with a wavelength from 400 nm to 100 nm and thus helps protect of human skin against sunburn.  Sunscreens contain one or more of the following chemical ingredients:

● organic chemical compounds, such as  p-Aminobenzoic acid and Ecamsule, which absorb ultraviolet light and release as it as heat.

● inorganic particulates, such as titanium dioxide, zinc oxide, or a combination of both, which reflect, scatter, and absorb UV light.

The UV light dressed in sunscreen products can be subdivided into UV A, UV B, and UV C.  UV A with a wavelength from 320 – 400  penetrates deeply into the skin and can lead to cancer and premature skin aging,  B with a wavelength from 280-320 causes your skin tanning and burns  your skin, and UV C with a wavelength from 280-320 is completely absorbed by the earth's ozone layer and atmosphere.

Chemistry in daily life - detergents

Detergents are liquid soaps containing a surfactant or a mixture of surfactants with "cleaning properties" in dilute solutions. But they're really different to the traditional soaps. which were originally made from natural products like vegetable oils, animal fats and wood ash. Detergents today are more likely a mixture made of synthetic chemicals and additives, which are used in many everything from hair shampoo and clothes washing liquid to shaving foam and stain removers.

The most important ingredients in detergents are surfactants— act chemically as surface active agents, which are compounds that lower the surface tension (or interfacial tension) between two liquids or between a liquid and a solid.
 

Surfactants may have many functions in today’s detergents, which may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants. Composition and structure of surfactants generally contain both hydrophobic  groups (their tails) and hydrophilic  groups (their heads).

Chemistry in daily life - soaps

From chemistry point of view, soap is a mixture of a base and an oil or a fat from chemical reaction with heating, known as saponification, during which sodium and fat are heated to form sodium salt of long-chain fatty acid.

The typical chemical equation for the formation of sodium stearate, for example, from neutralization of sodium hydroxide and stearic acid (fatty acid) as given below:

(C₁₈H₃₅O₂)₃C₃H_5(l)  + 3NaOH_(aq) → C₃H₅(OH)_3(l) + 3CH₃(CH₂)₁₆COONa_(aq)

Many cops are made from vegetable oils, such as olive oil, palm oil, rice bran oil coconut oil, and palm oil, other made of animal fats (tallows -  beef fat or lard – pig fat).

Soaps made from potassium hydroxide tend to be more soft and more soluble in water.

In households, soaps are mainly used as surfactants, which has both hydrophilic and hydrophobic parts, for washing, bathing, and cleaning. When soap, such as sodium stearate, dissolves in water, carboxylate anions and metal cations are produced:

CH₃(CH₂)₁₆COONa_((s)   + water  →  CH₃(CH₂)₁₆COO^-_(aq)    +   Na⁺_(aq)

Where the hydrophobic parts part with  long hydrocarbon chain attaches to non-polar grease and grime , while, the hydrophilic part, carboxylate anion end, is attached to polar water compounds by interaction of  ion-dipole.

As a cleaning agent, soap suffers from two major disadvantages during washing. It will function well either in acidic water or in hard water with high mineral content of calcium and magnesium cations because of the following chemical reactions:

CH₃(CH₂)₁₆COONa_((s)   +  HCl_(aq)   →  CH₃(CH₂)₁₆COOH_(aq)   +  Na⁺_(aq) +  Cl^-_(aq)

2CH₃(CH₂)₁₆COONa_((s)   +  Ca²⁺ _(aq)   →  Ca[CH₃(CH₂)₁₆COO]_(s)   +  2Na⁺_(aq)

There are many types of soaps, depending upon the usage, which can be characterised as:

● Hard and soft soaps, everything in-between;

● Transparent soaps, which are made with some different ingredients, usually some form of alcohol to modify the process;

● Glycering soaps, which are made with addition of glycerine, which acts as a humectant,  in them tend to make your skin feel moister;

● Medicated soaps, which are made with addition of compounds such as triclosan or triclocarban to have antibacterial and disinfectant functions;

● Scouring soaps, which are made with addition of sand or pumice to remove dead cells from the skin surface being cleaned

● Liquid soaps -  which are actually very difficult to produce and are just in fact commercial detergents (see Chemistry in daily life -  detergents).