How can enzymes affect the clarity of juice produced?
The key of producing clear and stable fruit juice is a complete enzymatic breakdown of pectin. Pectins make the clarification process harder because of their fiber-like molecular structure. Enzymes (particularly pectinases) can play a key role in improving juice clarity and stability as well as reducing the viscosity.
What enzymes can be used for juice clarification processing?
Commercial pectic enzymes and other enzymes like amylases, cellulases, glucose oxidase etc. are now an integral part of fruit juice technology. They are used to extract, clarify, and modify juices from many fruits including berries, stone, and citrus fruits, grapes, apples, pears.
Why is pectinase and protease added to fruit juice?
The protease treatment resulted in significant reduction of immediate turbidity, but had low clarification impact during the subsequent cold storage. In contrast, pectinase addition exerted a weak effect on immediate turbidity reduction, but effectively decreased the turbidity development during storage.
What is the role of enzymes in juice processing?
Enzymes degrade pectin or cell wall, allowing the more juice for extraction per ton of fruit. In some cases, the addition of enzyme complex can result in improved yield for the juice and in a better extraction for colour, with the outcome being a high-end product [13].
How does lemon juice affect an enzyme?
The browning can be slowed down by preventing the enzyme from working properly. Lemon juice contains an acid which can stop enzymes working properly as enzymes often work best at a certain pH. Water and sugar, in jam for example, stops oxygen in the air getting to the enzymes and prevents the browning.
What fruits are affected by enzymatic browning?
The enzymatic browning has been considered as a significant problem leading to economic losses of fruits like apples, pears, bananas, grapes, etc. and vegetables like lettuce, potatoes, mushrooms, etc.
What is clarification of fruit juice?
The production of clear apple juice requires the removal of suspended material and prevention of the development of turbidity after juice bottling. Freshly pressed juice contains suspended solids that are deliberately precipitated prior to filtration. This precipitation step is called clarification.
What is used in clarifying bottled juices?
Bottled juices are treated with following two enzymes in order to make them clear: 1. Pectinase: Pectinase is a class of enzyme which is used to break down pectin. These enzymes are also referred to as pectic enzymes, that includes pectolyase, polygalacturonase and pectozyme.
Does orange juice contain enzymes?
This is because orange juice naturally contains large amounts of pectin esterase — an enzyme that strips methoxyl groups from the pectin molecules (see Figure 6). This enzyme is found in many commercial pectinase preparations.
Which enzymes are used in fruit juice?
There are mainly two groups of enzyme which are used in fruit juice industry i.e. pectinases and amylases.
Are apples affected by enzymic browning?
Enzymatic browning is not unique to apples. Pears, bananas, and eggplants also turn brown fairly quickly when cut. Enzymatic browning is also responsible for the desirable dark color of prunes, coffee, black tea, and cocoa. To reduce browning in apples, keep the slices refrigerated to slow the reaction.
Which is better for juice clarification protease or pectinase?
How does pectinase and protease work to reduce turbidity?
In contrast, pectinase addition exerted a weak effect on immediate turbidity reduction, but effectively decreased the turbidity development during storage. The phenolic acid additions contributed to reduce turbidity when added together with the pectinase or the protease.
Which is better for cherry juice gallic acid or protease?
We previously found that treatment of cherry juice with an acid-stable protease, a pectinase, and gallic acid improved cherry juice clarity and diminished haze levels during cold storage ( Meyer et al., 2001 ).
Why do you add protease to kiwifruit juice?
Dawes et al. (1994) demonstrated that addition of a fungal acid protease to kiwifruit juice decreased the immediate turbidity and retarded the haze formation during cold storage.
The protease treatment resulted in significant reduction of immediate turbidity, but had low clarification impact during the subsequent cold storage. In contrast, pectinase addition exerted a weak effect on immediate turbidity reduction, but effectively decreased the turbidity development during storage.
How is the Brix of a juice determined?
Brix (symbol °Bx) is a measure of sugars, vitamins, minerals, proteins and other solid content in plant juice. Brix is determined by extracting the juices of a fruit or plant and using light refraction to determine the density of the sugars and other dissolved solid content.
In contrast, pectinase addition exerted a weak effect on immediate turbidity reduction, but effectively decreased the turbidity development during storage. The phenolic acid additions contributed to reduce turbidity when added together with the pectinase or the protease.
We previously found that treatment of cherry juice with an acid-stable protease, a pectinase, and gallic acid improved cherry juice clarity and diminished haze levels during cold storage ( Meyer et al., 2001 ).
