Cell
The cellular components are divided into two categories; protoplasmic protoplasmic not.
Protoplasm is the active part of the cell life and contains some components. Chloroplasts are present in green plants that contain chlorophyll. Non-protoplasmic cellular components incorporating cavities contain vacuoles called cell sap. Cell sap is an aqueous material containing various substances such as sugars, salts, organic acids, polysaccharides, phenol derivatives, flavones and red or blue pigments (anthocyanins). The liquid in the cell vacuole is responsible in terms of fruit and vegetable texture.
The cell walls
The components of the cell are covered by a wall which is responsible for the texture of the fabric. The cells are interconnected by intercellular layer or middle lamella. In the immature cell, the outer wall (IM) is initially created. soft tissue that occur in some fruits contain only primary walls.
The primary wall is composed of cellulose, hemicellulose, pectin and certain. In some tissues secondary wall is produced inside of the main wall.
The properties of the constituents of the cell wall:
Cellulose - is produced on a large scale and it is important in terms of the cell wall firmly. The level of the hemicellulose of the plant is reduced by the cooking process. Hemicellulose present in apples, tomatoes, pears and citrus fruits xylose. The cell walls of many fruits contain mannan.
Lignin - which is also a major constituent of cell walls. Gums - is another carbohydrate component of the cell wall. Pectin - apples and citrus albedo containing a large amount of pectin material. Pectin is pectic acid, pectinic acid, pectin and protopectin.
Changes during cooking and processing:
Thermal treatment of fruits and vegetables is a crucial process of conservation. When the pectic substances in the cell walls decompose softening of the cell wall and subsequently, separation can take place.
Divalent ions can increase the firmness of canned fruits, canned tomatoes and the cooked carrots. The divalent ion to crosslink between the carboxyl groups of pectin molecules of acids, will improve the firmness of the middle lamella and primary cell wall. When the pH increases from 3 to 8, the rigidity of the core decreases as the separation cells increased.
Color
Color can be the most important factor affecting the attractiveness of fruits and vegetables. Chlorophyll - This is the green pigment in plants involved in the chloroplasts. Chlorophyll is soluble in solvents such as diethyl ether, ethanol, acetone, chloroform, carbon disulfide, benzene and fats. Chlorophyll (a) is blue-green, chlorophyll (b) is yellow-green.
Changes during heating processes:
The modifications that occur in green vegetables pigments may be related to the chlorophyll properties. Chlorophyll from vegetable raw materials can be protected from the acid in the cytoplasm of the cell by its position in the chloroplasts. The pH of all common vegetables is less than 7 because of the acids that are present in the cell cytoplasm. Both volatile and nonvatile acids are discharged for cooking vegetables. the acid released by the vacuole of the cells during heating are not able to influence the color of vegetables if they are neutralized by boiling water.
The pH of the water can be reduced by boiling the carbon dioxide is released (dissolved in water to produce carbonic acid) or bicarbonate are converted into carbonates with release of carbon dioxide, or if the sulfide hydrogen is lost. The amount of acid which can be neutralized by an alkaline cooking water and depends on the alkalinity of the water volume. Degree water can provide a desirable green color because neutralize or at least dilute acids plants.
In the bleaching process can reduce the acidity and pH of vegetables is increased. The green vegetable color change sensitivity when cooking is influenced by their content of chlorophyll and its pH. frozen vegetables contain more chlorophyll as they initially retained a higher percentage during cooking. If green vegetables are heated as quickly as possible, the color did not / would change a bit. canning process has a significant effect change color in green vegetables resulted from the conversion of chlorophyll to pheophtin.
Carotenoids; the yellow and orange color and a portion of the red color of fruits and vegetables are caused by carotenoids that are found in chromoplasts cells. Carotenoids are insoluble in water but soluble in fats and organic solvents. Carotenes contain only carbon and hydrogen and are soluble in petroleum ether.
Xanthophylls; carotenoids containing oxygen, are soluble in alcohol.
Conclusion
Fundamentally, the degree of color change and the texture depends on the acidity of the cooking medium, the pH of the vegetation, the chlorophyll content and the time and the cooking temperature.
Pectins present in the vegetables to form water-retaining gels which help to provide a plant structure. Pectins become soluble and are extracted into the manufacture of the cooking water cooked vegetables become soft.
Calcium Ca2 + ions found in hard water can form crosslinks between the pectin molecules making them less soluble and hard to keep the plant. The water content of the calcium ions can change the color of cooked vegetables, as well as its texture, but indirectly through its effect on the pectin molecules.
Like most plants need a certain degree of softening after heat treatment, baking in hard water means that it is necessary to achieve the optimum softening. In the longer cooking times more chlorophyll is converted into phenophytin and color becomes green Browner vegetables.
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