Fruit puree plants run fresh fruit in season and frozen fruit from cold storage the rest of the year. Frozen raw material handling refers to thawing and conditioning frozen fruit so an existing puree line can crush, mill and sterilize it as usual. Whether the off-season actually gets covered comes down to three things: the thawing plan, process figures recalculated for thawed fruit, and telling the equipment maker about frozen material at selection stage.
Why not drop frozen blocks straight in?
Frozen fruit sits in storage at around -18 °C. By the time a case leaves the store the outer layers have softened while the core is still solid, and a crusher fed with that mix sees hard and soft fruit in the same hopper. Particle size wanders, the pulper load swings and the screen output drifts with it. When thawing goes wrong, every stage downstream pays for it.
|
Route |
Pace |
Where it fits |
|---|---|---|
|
Slow thaw in cold room |
counted in days |
production planned ahead, quality first |
|
Water thaw |
counted in hours |
modest batches needed the same day |
|
Partial thaw, then crush |
skips the wait |
line with crushing capacity to spare |
None of the three routes is the universal answer; variety, block size and line rhythm decide. Partial thaw, then crush skips the wait, but whether it works has to be confirmed against block size, feed temperature and what the equipment allows, with a trial where needed. Water thaw runs under controlled water quality, temperature, time and hygiene, since microbial growth during thawing needs to be kept in check.
Yield looks better, so why be careful?
Freezing and thawing splits open cell walls, so juice leaves the fruit more readily than with fresh material, and some plants treat that as a bonus. But juice yield and finished product quality have to be assessed separately: freezing and thawing can change flavour, colour and juice release, and whether the result meets the product's requirements follows from the material, the storage conditions and a small trial.
What does the line need to take frozen fruit?
When a fair share of the year runs on frozen material, say so at selection. Feeding needs a spot to break down blocks and crusher clearance should be adjustable. Heating and enzyme treatment conditions have to be reconfirmed against feed temperature, residual ice and the characteristics of the material.
Output needs recalculating too. On the assumed 5 tonnes per hour line from the capacity article, frozen batches are sized on what actually enters the line after thawing, not on store weight, with drip loss and sorting waste folded in. That is the figure the schedule and the machine load should agree on.
At signing, both sides do better to put the raw material picture on the table: the plant shares how its year splits between fresh and frozen, and the supplier quotes configuration and output for each case. Changing a line to suit frozen fruit after start-up costs far more than saying so up front.
Not every product suits frozen material: whether an aroma-led clear juice works follows from the material, the storage conditions and a small trial, and tighter in-season scheduling is often the safer call.
The order to keep: check what the store actually holds, pick the thawing route, recalculate output and process figures for thawed fruit, and tell the equipment maker about frozen material before the contract is signed. Frozen fruit fills the off-season only when the line has been given room for it.