Fruit juice in general is a colloidal mixture of soluble and suspended solids, containing low molecular-weight solutes, such as sugars, organic acids, pigments and vitamins. Fruit juice also having high-molecular-weight solutes, such as proteins, enzymes and pectic substances.
The primary pasteurization is done after juice extraction, or as a first step in the evaporator. This pasteurization is commonly done at 95–98°C for 10 to 30 seconds. The main objective is to increases shelf life by inactivating certain enzymes and microorganisms such as yeasts, molds and bacteria.
The second pasteurization is carried out before filling the juice in its container. The goal of the second pasteurization is to destroy the microorganisms that occur as recontaminants in the fruit juice after bulk storage or in juice reconstituted from concentrate. The second pasteurization of fruit juices normally done with a pH below 4.2 are a temperature of 95°C and a holding time of 15 seconds.
Once pasteurization process completed, there is increasing in viscosity about 7% and a 22% decrease in cloud were observed after 21 days of shelf life. The main goal of pasteurization process is to minimize these undesirable reactions while at the same time in some cases, enhancing, the inherent quality of the starting fruit.
Pasteurization Of Fruit Juice
