Nature is a great chemist. It is playing with chemical pigments to present vivid colors. Even a single leaf is a piece of art. There are many classes of pigments present inside it but their amount and times of breakdown and synthesis decides the resultant color. The different colors are on display during autumn season. The leaves begin to look less and less green. They can take yellow, orange and red hues depending upon the ratios of the amounts of different pigments present in the leaves.
Most important pigment in the leaves is the chlorophyll. It is this pigment which imparts the green color to the leaf. It’s amount is dictated by the warmth and amount of sunlight the plant receives. It’s presence is the indication that plant is alive and carrying out photosynthesis to convert carbondioxide and water into sugars and oxygen. Sugars contain energy from the sun which is harvested by tree or plant during photosynthesis.
What happens when it is not sunny. We see a kaleidoscope of different colors in leaves. There are yellow, orange and red hues. These colors are attributed to other pigments present inside the leaves. These were there throughout the life of the leaf but there colors were masked by the strong green color.
In the autumn, when sunlight is not available in plenty, the production of chlorophyll is halted. On the other hand, the chlorophyll present begins to breakdown. At this time, color contribution from other pigments begin to show up.
Chlorophyll is a type of chlorine with magnesium as the central metallic ion. There are 4 nitrogen atoms which are Lewis bases and thus trap the positively charged magnesium ion. Chlorophyll is synthesized in the warm and sunny conditions by the plants. It’s green color dominates the color in the leaves. During autumn, the sunlight is not fully available and hence the production of chlorophyll halts and since it is not required the already present chlorophyll in the leaves begins to breakdown and hence result is the decrease in green color of the leaves.
Carotenoids and flavonoids are pigments which are always present in the leaves but there color is masked by the green color of the chlorophyll. When during autumn, the chlorophyll begins to breakdown, the color of these two classes of compounds begins to show up.
Xanthophylls which are oxygenated carotenoids are responsible for the yellow color of leaves. They do not require light for synthesis, so that xanthophylls are present in all young leaves as well as in etiolated leaves.
A class of carotenoids known as beta carotene is responsible for the orange color in leaves. It absorb light of green and blue wavelengths and reflects red and yellow wavelengths light thus causing the orange color in leaves during autumn. Beta-carotene are also responsible for this color in carrots. They begin to degrade at the same time as chlorophyll but at a slower rate thus showing up the orange color gradually.
There is another class of compounds called anthocyanins which begins to get synthesized in the mature leaves due to the high amount of sugars in them. These are red in color. These are thought to prolong the falling of leaves.
“Our limbic brains love sugar, fat, salt.… So formulate products to deliver these. Perhaps add low cost ingredients to boost profit margins. Then “super size” to sell more.… And advertise/promote to lock in “heavy users.”” —Bob Drane, former vice president for new business strategy and development at Oscar Mayer.
From this statement, it is clear that foods containing Sugar, Fat and Salt appeal most to the human brain. Armed with this knowledge, the fast food companies design feel good foods and hook so many of us, particularly, the younger generation. It is the right combination of these that is important. The malaise of obesity is the result of those extra pounds generally come from the over consumption of soft drinks, snack foods, and fast foods.
Of course, the food companies do not want their customers obese because in that case they may start avoiding the fast food. But they want the “stomach share” in the food market. But processed-food companies increasingly turn to their legions of scientists to produce foods that we can’t resist. These food geeks tweak their products by varying the levels of the three so-called pillar ingredients—salt, sugar, and fat.
It turns out that although we generally do like such food more but after a certain intake, we like to take less. That optimum amount of salt, sugar, or fat is called the “Bliss Point”. Scientists also adjust these ingredients as well as factors such as crunchiness to produce a mouth feel—that is, the way the food feels inside a person’s mouth—that causes consumers to crave more. Technologists can also induce a flavor burst by altering the size and shape of the salt crystals themselves so that they basically assault the taste buds into submission.
The formula of successful junk-food science is the vanishing calorific density. Such food melts in your mouth so quickly that the brain is fooled into thinking it’s hardly consuming any calories at all, so it just keeps snacking. In the process, packaged-food scientists want to avoid triggering sensory-specific satiety, the brain mechanism that tells you to stop eating when it has become overwhelmed by big, bold flavors. Instead, the real goals are either passive overeating, which is the excessive eating of foods that are high in fat because the human body is slow to recognize the caloric content of rich foods, or auto-eating: that is, eating without thinking or without even being hungry. (The opposite problem is being overhungry, where you’re so ravenous that you’ll basically eat anything that’s put in front of you.) Either way, if you end up with a food baby, a distended stomach caused by excessive overeating, you’ve made a fast-food executive somewhere very happy.
All this is explored by Pulitzer award winning Journalist Michael Moss in his book “Salt Sugar Fat: How the Food Companies Hooked Us”
Caramel is used in many recipes. It is prepared by heating the sugar and sugar becomes syrupy and turns brown and a mouth watering aroma is released. Most people think that during heating the sugar, it melts and goes into a liquid state. But this is not true. There is chemistry behind this although no reactions really take place but there are phase changes. So physical chemistry is behind all this process.
Melting point of a substance is defined as that temperature at which the solid begins turning liquid. For pure substances consisting of single compounds this temperature is well defined and constant at atmospheric pressure. The one condition for the melting point definition is that the substance should not not breakdown during the melting. If there are impurities in the form of other substances and contaminants the melting point is not sharp and there is a range in which the whole process of melting takes place.
When sugar is heated to 160 degree centigrade, it turns into a colorless molten mass. In fact, the literature gives different melting points for the sugar. What happens is that during heating to 160 degree centigrade and further heat is supplied, temperature does not remain constant as should be the case. Near this temperature the sugar molecules also begin to disintegrate and some lower molecular weight compounds are formed. On further heating by 10 to 20 degrees, caramalization begins and it starts to turn brown emitting a mouth watering aroma.
It has also been proved that caramelization is a function of both time and temperature as many other chemical reactions are. For example, the theory for conversion of deposited organic matter to the hydrocarbons is a function of time and temperature. The effect of time is linear and that of temperature is exponential. This is known as famous Arrhenius equation. In simple words, the temperature increase is ten times more effective than time passage.
So when the sugar temperature is raised above 160 degrees, depending on the time and temperature control, different colored crystals can be obtained. and thus can be achieved to different colors by adjusting the temperature and time of heating. Following are the results from “curious cook” website.
Honey is thought to be very healthy sweetener. It is produced by bees as their food source and made from nectar sucked from the flowers with the help of enzymes. The final product is made of roughly 80% sugar, 17% water and a number of trace compounds. It is these trace compounds that are responsible for honey’s varied flavors and colors. The most abundant sugars in honey are fructose and glucose. Among the myriad minor complex sugars in the honey are maltose, sucrose, and other disaccharides, as well as trisaccharides such as erlose.
The nectar is mixed with enzymes, Invertase being the most critical, in their stomach-like honey sacs. Invertase splits the sucrose in the nectar into fructose and glucose and also produces some erlose. Back at the hive, the bees pass the digested material to house bees who reduce the moisture content of the mixture by ingesting and regurgitating it. They then deposit concentrated drops into honeycomb cells. Over the next few days, bees fan the fluid with their wings to further concentrate it, and finally, they cap the cells with wax. At the same time, enzyme-mediated changes produce a range of sugars and acids in the honey. Bee enzymes also show up in the finished product. Another enzyme, glucose oxidase, converts glucose to gluconolactone, which is then hydrolyzed to give gluconic acid, the principal acid in honey. Formic, acetic, butyric, and lactic acids are also found in honey, which explains why its pH typically measures 3.8-4.0 which is quite acidic and inhibits the growth of any bacteria in it.
Honey also contains small amounts of minerals and proteins. About 0.2% of honey is ash, probably originating in the flower nectar. Potassium accounts for about one-third of the ash. Other trace elements in honey include iron, manganese, copper, and silicon. The sweetener also contains up to 1% nitrogen, which comes principally from proteins. These proteins can cause honey to foam and form tiny air bubbles.
Of the more than 100 compounds found in honey, many are volatile organic compounds, such as phenylethyl alcohol, that contribute to flavor. The honey flavor is dependent on the flavor compounds and aroma compounds that come from a flower.
Because weather and geography affect flowers, each batch of honey can have a slightly different makeup of flavor chemicals.
Sugar has become a dreaded word in the modern world. The term is used for the diabetes disease which is acquiring the epidemic proportions in the world. Although sugar alone cannot be blamed for this disease. Sugar is the major energy source along with fats on which our body runs. Even the carbohydrates which we take in the form of bread and rice are ultimately broken down to simpler sucrose and then glucose compounds and are assimilated by our bodies. It is a matter of living style like stressful life, overeating and sedentary habits. So let us not blame sugar and know about it.
Sugar cane is a grass and the source of 70% of the world’s sugar which is extracted from the sweet, juicy stems. In many South Asian countries like India and Pakistan, when the stalks of sugarcane mature, they are chewed for their sugary syrup. The stalk is divided into pieces like the bamboo stalk and sweetness of the stalks decreases from bottom towards upper stalks. Of course, green portion at the top is only grassy. It is eaten as small pieces by the children. This was the original use of sugar cane. Afterwards the sugar extraction processes began and it became the most important source of sugar followed by the beetroots and palms. The juice is extracted by pressing the sugarcane in a press consisting of rollers of steel and operated by bullocks or nowadays with engines. Area of West Maharashtra near Nashik are famous for the sugarcane production. Uttar Pradesh also produced lots of sugarcane. There are many mills for large scale production of sugar and molasses.
Sugar cane originated in New Guinea where it has been known since about 6000 BC. From about 1000 BC its cultivation gradually spread along human migration routes to Southeast Asia and India and east into the Pacific. It is thought to have hybridised with wild sugar canes of India and China, to produce the ‘thin’ canes. It spread westwards to the Mediterranean between 600-1400 AD.
Arabs were responsible for much of its spread as they took it to Egypt around 640 AD, during their conquests. They carried it with them as they advanced around the Mediterranean. Sugar cane spread by this means to Syria, Cyprus, and Crete, eventually reaching Spain around 715 AD.
Around 1420 the Portuguese introduced sugar cane into Madeira, from where it soon reached the Canary Islands, the Azores, and West Africa. Columbus transported sugar cane from the Canary Islands to what is now the Dominican Republic in 1493. The crop was taken to Central and South America from the 1520s onwards, and later to the British and French West Indies.
Indian Subcontinent
Sugar cane has a very long history of cultivation in the Indian sub-continent. The earliest reference to it is in the Atharva Veda (c. 1500-800 BC) where it is called ikshu and mentioned as an offering in sacrificial rites. The Atharva Veda uses it as a symbol of sweet attractiveness.
The word ‘sugar’ is thought to derive from the ancient Sanskrit sharkara. By the 6th century BC sharkara was frequently referred to in Sanskrit texts which even distinguished superior and inferior varieties of sugarcane. The Susrutha Samhita listed 12 varieties; the best types were supposed to be the vamshika with thin reeds and the paundraka of Bengal. It was also being called guda, a term which is still used in India to denote jaggery. A Persian account from the 6th century BC gives the first account of solid sugar and describes it as coming from the Indus Valley. This early sugar would have resembled what is known as ‘raw’ sugar: Indian dark brown sugar or gur.
At this time honey was the only sweetener in the countries beyond Asia and all visitors to India were much taken with the ‘reed which produced honey without bees’. The Greek historian Herodotus knew of the sugarcane in the 5th century BC and Alexander is said to have sent some home when he came to the Punjab region in 326 BC. Practically every traveler to India over the centuries mentions sugarcane; the Moroccan Ibn Battuta wrote of the sugarcanes of Kerala which excelled every other in the 14th century; Francois Bernier, in India from 1658-59, wrote of the extensive fields of sugarcane in Bengal.
Raw and refined sugars in simple terms are produced by heating, removing impurities and crystallizing sugar cane juice. Sucrose is the main constituent in this juice. Raw and refined sugars are exported all over the world for use in pretty much everything from sweet and savoury dishes to processed foods and drinks and preserving fruits and meat. These sugars are also compressed into sugar cubes or made into syrup. White sugar can be further processed into icing sugar to be used in desserts, baking and confectionery. It is a dark, syrupy product and is used for the preparation of edible syrups and for numerous industrial products. In Brazil alcohol is prepared from the sugarcane juice and is used as a fuel for the automobiles. Its end products after burning are carbondioxide and water which are completely pollution free.
As the sugar cane juice contains energy giving sugar as well many minerals, it is used in the treatment of certain illnesses. Both the roots and stems of sugar cane are used in Ayurvedic medicine to treat skin and urinary tract infections, as well as for bronchitis, heart conditions, loss of milk production, cough, anaemia, constipation as well as general debility. Some texts advise its use for jaundice and low blood pressure.
A very surprising use of sugar is for removing body hair. A warm paste of sugar, water and lemon juice is applied to the skin. Strips of cloth are then pressed over the paste and are then quickly torn off, taking the hair with them. Enthusiasts claim that this procedure becomes less painful with time. The practice of sugaring may date to ancient times in South Asia.
In Indian Literature
Indian literature abounds in references to the sugarcane: early Tamil literature describes sugarcane along the banks of the River Kaveri, and indeed sugarcane was usually cultivated in river valleys. Early Indian kings set aside land for pleasure gardens, groves and public parks, and gardens were attached to palaces and grand mansions. The Kamasutra, an early erotic treatise written by Vatsyayana (c. 2nd century AD – c.4th century AD), recommended that a cultivated and wealthy man should surround his house with a garden.
The garden would be under the care of his wife who would dictate the layout of the garden and its planting, while the physical labour was left to professional gardeners. The Kamasutra spoke of pleasure gardens and practical gardens and was specific about what should be planted in the gardens. The practical garden had to include beds of green vegetables, sugarcane, fig trees, mustard, parsley and fennel. The great goddess Kamakshi of Tamil Nadu is portrayed in art holding in her four hands lotus blossom, sugar cane stalks, elephant goad and noose.
