Pasteurization Of Fruit Juice

Freshly extracted juice, is highly susceptible to spoilage. The objective of thermal process is to make the juice product stable during its planned storage period. Also, pasteurization process led to a significant improvement in the organoleptic characteristics of the juice. The unheated juice is subject to rapid microbial, enzymatic, chemical and physical deterioration.

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

Enzymes in Fruit Juices

Enzymes in Fruit Juices
Fresh juices are chock full of enzymes – those “living” molecules that work, often with vitamins and minerals, to speed up reactions necessary for the human body to function.

Without enzymes, we would not have life in our cells.

Enzymes are prevalent in raw foods, but heat such as cooking or pasteurization, destroys them.

Fresh fruit juice contains enzymes that help break down food in the digestive tract, thereby sparing the body’s digestive system from overwork.

This sparring action is known as the “law of adaptive secretion of digestive enzymes.”

According to this law, of some of the food you eat is digested by enzymes from the food itself, the body will secrete less of its own enzymes.

This allows the body’s energy to be shifted from digestion to other functions such as repair and rejuvenation.

Fresh fruit juices require very little energy expenditure to digest. And that is one that their energy levels increase.
Enzymes in Fruit Juices

Fruit Juice Processing

Fruit Juice Processing
The majority of fruit juice is made by reconstituting concentrated juice with water to a composition as similar to that of the original state. However, since records are not usually kept of the exact quality of the original juice, such reconstitution normally relates to an agreed trade standard. Reconstituted juices are often packed in aseptic long life containers such as TetraPaks.

There are many countries a growing market for fresh ‘single-strength’ juice made by squeezing fruit. Subjecting it into some processing, packaging it selling it within a cold chain distribution system. Such juice is usually referred to as ‘not from concentrate’ and will have a shelf life that varies from 1 or 2 weeks to 2 or 3 months.

In general terms, fruit are collected, sorted and washed, and then subjected to a type of mechanical compression appropriate to the fruit concerned. Although there are general fruit presses that can be used for more than one fruit type, fruit such as citrus, pineapple and stone fruits are usually processed in specially designed equipment.

Some fruit types (such as apples and pears) require mechanical treatment (milling) coupled with a biochemical process (involving enzymes) to break down the cellular structure and obtain best yields. It is possible to achieve almost total liquefaction by means of an appropriate enzyme cocktail.

Additionally, a diffusion or extraction process can be used to obtain best yields from certain fruits.

If juice is to be sold as ‘not from concentrate’ it is usually screened and pasteurized immediately after pressing – an operation with two main objectives. The first is to control the growth of spoilage micro-organisms that live on the fruit surface (mainly yeasts and moulds). The second is to destroy the pectolytic enzymes that occur naturally in fruit that would otherwise breakdown the cloudy nature of the juice. If, however, a clear juice is required, enzymes can be added to accelerate this natural process.

Juice for concentration is normally subjected to screening to remove cellular debris and then fed to a one or multistage evaporation process to remove most of the water and other volatile material. Evaporators today are highly efficient processing unit: up to nine stages are used, sometimes with the thermal recompression to obtain maximum efficiency. Increasingly, evaporators also recover the volatile aromatic substances that are partly responsible for giving fruit juice their sensory characteristics. The re-addition of such volatile is widely practiced at the point when concentrates are reconstituted into single strength juice.

After concentration, juices are normally held in storage until they are reconstituted. Some concentrated juices, particularly orange, require freezing at below -10 degree Celsius for effective preservation. Others, particularly apples, can be held at around 10-15 degree without risk of deterioration. The degree of concentration plays an important part in determining storage conditions: in the above examples, orange juice is normally concentrated to about 65 degree Brix and apple to 70 degree Brix.
Fruit Juice Processing

Papaya Juice

Papaya Juice
The outer skin of a papaya turns yellow or orange when it is ripe, and the flesh becomes sweet and soft. To prepare them for juicing, cut in half, scoop out the seeds and discard and then scoop out the flesh, throwing the skins away. Then run the flesh through juicer. The papaya can be blended with other fresh juices. Or if to make plain papaya juice, simply blend two to four ounces of water with the flesh of one medium sized papaya.

Papaya is rich in vitamins A and C, and contains small amounts of the minerals calcium, chlorine, iron, phosphorus, potassium, silicon and sodium. Its nutritional highlight is its enzymes, specifically papain, a protein digestant. It is also endowed with the abundance of energy-boosting natural sugars when ripe. Papaya juice strengthens the body’s blood coagulating ability. It is a fine laxative, appetite stimulant, and cleanser of the kidneys, liver, and intestines.
Papaya Juice