Human saliva is composed of water and enzymes. Water takes up the largest percentage and enzymes only forms a small percentage of the saliva. Amylase is an enzyme found in the saliva and is responsible for the breakdown of insoluble starch into sugars (Harrow 109). Salivary amylase also known as ptyalin work best at 37 degree Celsius; the enzyme is very sensitive to temperature changes; it functions best under normal body temperature. At higher temperatures the enzymes are denatured while at lower temperatures, their activities are lower and rate of digestion is reduced tremendously.
The enzyme amylase is also affected by the pH of the media in which it is operating. When all conditions are regulated and maintained at norm, the activities of the enzymes are highest. In their activities, enzymes break down into inter- and intermolecular bonds which consequently increases their surface for more activities (Dutta et al 2006). This way the enzymes are able to improve the rate of digestion
Enzymes actuates the biochemical reaction that takes place in the mouth as the food is crashed into smaller particles and mixed with the saliva containing ptyalin faster and more efficient. Amylase on its part helps in the breakdown of carbohydrates into sugar and it takes place in this reaction/process without being consumed (Shariffa 2009). Amylase has low activation energy and digestion thus takes pathway that is shorter than it would take without Amylase.
Many enzymes have a protein and a non-protein part (cofactor) in their structures. Enzymes have different and unique working pH where their activities are optimum; ptyalin works optimally when the pH value is maintained between 6.7 and 7.0. Below these values the rate of conversion of starch into sugars is observed to decrease steadily (Rosenblum 776).
Amylase fastens the digestion of starch by converting some of the ingested starch into sugars before it leave the mouth for the other digestive processes. The activities of the ptyalin are inactivated by lowering or increasing the pH. On reaching the stomach, the activities of Amylase are stopped by the presence of gastric acid which reduces pH to around 3.3. Many experiments have been performed with the aim of establishing the right pH at which digestion is optimum and the value of temperature and pH at which the results are obtained Previous experiments have indicated that a pH 3.3 stops the activities of the Amylase almost immediately, at pH 4.3 the activities of the ptyalin proceeded although it has been noted to be far too slow than it is at pH 7.0 (Rosenblum 776).
The value of pH at which activates of ptyalin is highest also has been found to vary with the prevailing body temperature. When the temperature of the body is low also the activities of the enzymes is found to lower. Other experiments have indicated that 5.6 can also be a comfortable ph value if the body temperature is maintained at body temperature (Holum 377).
Another interesting finding is that the level of amylase in the saliva is dictated by genes which have duplicated over the evolution period. The results also suggest that the level of genes also determines the level amylase in the saliva. These results also indicate that the level of pH is also genetically determined as the pH of the saliva also depends on the ratio of enzymes and water (Martinek 31).
In conclusion, knowledge about the standard pH in human saliva is important especially in the diagnosis of different ailments that can directly or in directed be related to genetic combination. Different enzymes required different operating environments, e.g. the other types of amylase enzymes the β-Amylase and γ-Amylase different pH levels compared with ptyalin (α-Amylase) which we have found to be working best under neutral pH condition or slightly acidic condition (Perry 1256). Unlike α-Amylase, γ-Amylase works best in acidic condition, of about pH 3.0.
pH is important in the digestion system of an individual, if wrong pH exists then the digestion of carbohydrates in the individual will never be completed as the condition necessary for complete digestion of them are lacking, on the other hand if the body system is working normally an d the pH level of the body is around 7.0 then the individual won’t have any complications that might arise from incomplete digestion or luck of selective nutrients n the body.