L. Pasteur was the first person who appreciates and understands the existence of microorganisms in food. He showed that the souring of milk is due to the presence of microorganisms in the milk. In 1860 L. Pasteur used heat treatment to destroy unwanted microorganisms in wine and beer. This process is now widely known as pasteurization. In 1868 he shipped a cargo of pasteurized wine all over the world to prove the affectivity of his discovery.
The modern pasteurization is known as the application of enough heat to a product for a certain period of time to kill pathogenic microorganisms, while leaving the product sensory and nutritional qualities remain undistracted. Total microbial destruction is not possible in pasteurization because microorganisms generally die in logarithmic fashion once exposed to heat. One log cycle reduction in survivors gives a 90 % reduction in number. The required time to complete the 90% reduction will depend on specific microorganisms and temperature in which the product is subjected. Thus pasteurization does not guarantee absolute safety, but promises a matter of reduction of risk.
Throughout the years demands on fruit juices became a trend, as well as the many approaches alternative to thermal process to preserve fruit juices, but thermal treatment remains to be the most cost-effective to ensure microbial safety and enzymes deactivation of fruit juices.
Modern pasteurization processing can be classified by the intensity of heat treatment applied to the product. There are two types or classification of modern pasteurization: the High temperature Long time (HTLT) and the High Temperature Short Time (HTST). HTLT is the most commonly used method for processing fruit juices and beverages. This method needs more than 80°C temperature with 30 more than 30 seconds holding time. While HTST requires a temperature equal or more than 80 °C and a holding time less than 30 seconds.
The main objective of this home-based trial is to be able to learn and apply the basic principles of pasteurization in various fruit juices.
Lemon juice and Coconut water both need pasteurization to extend its shelf life and to ensure microbial safety. But pasteurization also has drawbacks in fruit juices. Lemon juice can be easily affected by pasteurization due its delicate fresh structure; it may affect its color, taste and nutritive value. And due to its acidic nature lemon Juices are ideal to be subjected to High Temperature Short Time (HTST) pasteurization method during processing. It simply means that the the overuse of heat treatment may affect the juice quality in both physicochemical and sensory attributes.
The result shows that application of pasteurization process to different fruit juices needs thorough understanding the properties of the juice to ensure that the process is beneficial to the product. The lack of knowledge of the raw materials used in the product may end up with failure to extend the shelf life of the juices and loss of important qualities such as sensory quality and nutritive value of the product.
