Lemon + Rock Sugar = ???

So, what will be given by the mysterious reaction above? The answer is enzyme produced from the fermentation. Enzyme is made up of protein molecule that has unique spatial arrangement, called active site. The main function of enzyme is to catalyst biological activities like utilize nutrients and aid digestion.

Generally, enzyme can be divided into internal and external enzyme. Internal enzyme can found in body while external enzyme can be found in food. One question might arise here, why do we still need take in external enzyme from food when our body themselves can produce it? The answer is enzyme-deficient food intake would overburden our body by synthesizing internal enzyme to digest the food.

The main source of external enzyme comes from fruits, vegetables, meat and grain. Sadly to say, most enzymes contained in them have been destroyed when cooking under high temperature. For instance, protease in cooked meat is denatured and cannot be absorbed by body.

The best way of obtaining external enzyme other than eating a variety of foods and vegetable is drinking DIY enzyme, fruit enzyme. During the fermentation process, bacteria “per-digest” nutrients in fruits that ease the later absorption by body and enhance the enzyme level in fruit. The listed are the benefits of consuming fruit enzyme:

- Lower cholesterol level

- Maintain high alkali pH

- Strengthen the immune system

- Relieve constipation by promoting the proper digesting and elimination process.

- An antioxidant that protect body cells from neutralizing radical.

To explore its medication, effect and fragrant taste, let's look at the recipe. The ingredients needed are lemon, pineapple and brown rock sugar.

Firstly, clean and dry all the fruits, utensils and container. Make sure they are dried throughly and free from any water and oil stain. Next, slice fruit in 3-5 mm thick. Later, place fruit in the first layer, lemon at the second layer and following by brown rock sugar. Then, repeat the same process until it full and cover with the lid tightly.


Friday, 22 March 2013

Citric Acid



Citric acid is a colourless, crystalline organic compound belonging to the family of carboxylic acid. It is a slightly stronger acid than typical carboxylic acids because the anion can be stabilized by intramolecular hydrogen-bonding from other protic groups on citric acid. It is odourless with a strongly acidic taste, naturally occurring weak organic acid that exists in a variety of fruits and vegetables, but it is most concentrated in lemons and limes, where it can comprise as much as 8 percent of the dry weight of the fruit. With the molecular formula C6H8O7 , it is known that citric acid is made up of six carbon atom, eight hydrogen atom and seven oxygen atom. Citric acid's mild acidity is the result of three carboxyl groups (three compounds made up of a carbon atom bound with two oxygen and one hydrogen atoms). Its 2D structure and 3D conformer are as shown:

                             

Citric acid has many uses including act as a flavor enhancement, bacterial inhabitant, pH adjustment, and as an antioxidant. During the fermentation of fruits in the preparation of fruit enzyme, lemons which rich of citric acid are used so that the pH will be low enough to safeguard against infection. If the pH is high without lemons, the fermentation will be susceptible to bacterial infections. Besides, citric acid stabilizes sweets and confectionery, thus it is able to prevent crystallization of sucrose during fermentation.

Why apple turn brownish??

Oxygen is metabolized by the cells on the fruit's surface (oxidation). Free radicals are formed-- these are atoms with unpaired electrons. Having an unpaired electron makes them really unstable, so they attack surrounding stable molecules and steal electrons. This initiates a domino process of electron stealing and eventually causes cell damage. Hence, as an antioxidant, citric acid has extra electrons, so they bind to free radicals, neutralizing them by donating one of their own electrons. That domino chain of free radicals stealing electrons cannot occur. In other words, citric acid can be used in food industry to prevent browning of fruits and vegetables. It lowers the pH of the fruit tissue to retard the action of the phenolase. If the pH is reduced below 3.0, the activity of the phenolase will be severely inhibited.



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