The majority of agricultural products will reveal physical appearance remains good although the material has been dried and partly physical properties will change. The physical properties of materials is a hallmark of an agricultural product that directly or indirectly affect the level of consumer acceptance. Therefore, the physical properties of the material must be constantly maintained in order not undergone many changes from its original properties.
For this type of food grains tertentuseperti reduced water content did not affect the physical properties of materials. Agricultural products such as fresh fruit and vegetables, the loss of a number of water can change the physical properties of the material so that the quality is lower. Therefore, in dealing with the nature of agricultural produce should look for the best way that the substance has not changed much his appearance, especially his outward appearance, because it is a criteria for consumers in choosing a food ingredient.
Agricultural produce can be viewed as a period that still has the nature of life. Although it has been picked or separated parent plants, agricultural output would still be able to continue the change. Changes that occur in the form of the continued growth and other physiological processes. Such as fresh fruits and vegetables will undergo a process of maturation.
- Chemical (nutritional value)
Agricultural products are chemically composed of essential components such as carbohydrates, proteins, fats, vitamins and minerals. The compound compound used as an energy source and the basis of cells for humans or animals. Therefore, it is desirable agricultural produce can maintain what it implies to materials consumed. The content of the nutritional value of agricultural produce is directly influenced by the events that took place biologically, for example, seed germination. Energy required for germination ongoing. Growth energy derived from carbohydrates and protein and fat contained in these seeds. Therefore, in every germination, an important compound content will be reduced.
- Sugar content changes
Changes in sugar content in food is used to measure or determine the activity of respiration, but it is practically difficult to do because the sugar contained in the material amount is not fixed. This is because the formation of sugar degradation products of carbohydrates along with degradation of sugar in the process glikolosis.
- The content of ATP (Adenosine Tri Phosphate)
The content of ATP produced during the metabolism process can theoretically be measured, but in practice very difficult to do, because in order to to calculate the amount of ATP formed it takes a long time and high accuracy.
- CO2 production
The amount of CO2 produced during respiration Yag relatively large, making it easy weeks to make the measurement. In plant respiration process can actually be aerobic and anaerobic. Anaerobic respiration is the respiration process by using electron acceptor compounds instead of oxygen, but the organic compound is oxidized organic compounds reduced e (energy) use of the compound contained in the material itself, known as the fermentation process. Therefore, measurement of respiration by measuring the amount of CO2 that comes out, it will not be known whether it is aerobic respiration and anaerobic.
While the respiration takes place by means of oxidizing protein RQ it will produce approximately 0.80. So if RQ = 1, the possibility of oxidized material which is carbohydrate. When the value RQ = 0.71 materials that undergo oxidation process is fat, whereas when RQ between 0.71 to 1.0 means that the oxidized are mixed.