Stone Fruit / processing line
Plum Processing Line
Depicted route: Plum puree
Plum varieties differ in skin, colour, firmness and stone adhesion. A line introduction should therefore distinguish clean pitting from the later decision to retain flesh as purée or recover a juice stream. Sort plums by processing condition, wash and separate stones. Retain or remove skin according to the desired colour and texture, then pulp or extract for the selected product. Fresh-plum processing should be distinguished from the water-extraction route used when the incoming material is dried prunes.
Raw material and product boundary
Product directions
- purée
- juice base
- jam
Incoming material considerations
- Will raw material be fresh plums or dried prunes, and which preparation steps belong in the actual project scope?
- How much skin-derived colour and coarse texture should remain, and can the pitting section handle the specified varieties without excessive broken-stone carryover?
- Define incoming state, variety, maturity, accepted defects and supply interruptions in the purchasing brief. A proposed line should be demonstrated with representative commercial lots rather than a single ideal sample.
Process flow: preparation to product
- 01
Receive by variety
Equipment duty: Fruit inspection conveyor and grader
Document the accepted plum lots and remove unsuitable fruit.
Evaluate skin condition and firmness with the size distribution instead of specifying fruit weight alone.
- 02
Wash and rinse
Equipment duty: Washer and controlled elevator
Clean fruit before the edible fraction is exposed.
Keep rejected fruit, loose soil and dirty water out of the pitting section.
- 03
Separate the stone
Equipment duty: Plum-compatible destoner
Recover flesh while controlling stones and fragments.
A clingstone supply needs its own demonstration; it should not inherit a free-stone acceptance result without review.
- 04
Develop the product fraction
Equipment duty: Pulper-refiner or juice-separation equipment
Prepare the declared purée or juice intermediate.
Keep the desired skin-derived colour and suspended material visible in the product specification.
- 05
Finish and sample
Equipment duty: Screening or refining stage
Remove coarse particles to the accepted level.
Taste and assess the product after consistent handling, not simply by comparing newly drawn samples at different settings.
- 06
Route the approved stream
Equipment duty: Covered tank and suitable pump
Supply the specified single-strength, concentrated or formulated-product route.
Separate optional concentration from the basic pitting and extraction supply.
- 07
Specify preservation around the actual product
Equipment duty: Selected treatment unit, controlled transfer and process instruments
Confirm the measured product composition, particulate load and intended storage chain before the treatment and filling arrangement is selected.
The pitted purée or juice base route needs its own validated process. A drawing, a heat-exchanger name or a successful extraction trial does not establish a safe treatment schedule or a finished shelf-life claim.
- 08
Fill, identify and verify the packed ingredient
Equipment duty: Compatible filler, packaging interface and lot-identification station
Match the approved ingredient to the selected package and handling conditions. Record the production lot and the conditions required by its defined distribution route.
The filling boundary belongs in the project specification: container format, product-contact interface, filling hygiene, storage and the downstream user’s receiving requirements must agree before commercial acceptance.
Equipment composition and selection
Fruit inspection conveyor and grader
Control the incoming-material presentation before preparation.
Selection basis: Check actual lot condition, peak arrivals and the accepted size range. Provide a sample/reject point that can be operated without obstructing feed to the next machine.
Plum-compatible destoner
Pitting and flesh finishing.
Selection basis: A pitting demonstration should account for stone fragments, retained flesh and the rejected fraction. Additional recovery from stones must not compromise the finished product acceptance criteria.
Pulper-refiner or juice-separation equipment
Create the agreed intermediate condition for downstream equipment.
Selection basis: Agree an acceptance sample, a measurable particle or separation target and a reject-handling method. Select contact parts and access arrangements after trials with representative material.
Product buffer and transfer system
Connect preparation, treatment and filling without assuming all sections run at the same rate.
Selection basis: Record viscosity, particle character, temperature envelope and expected stoppages. Confirm drainability, sampling points and how unaccepted or interrupted product is identified and handled.
Preservation, packaging and cleaning interfaces
Complete the declared process boundary.
Selection basis: The quoted scope should identify included instruments, services, containers, hygienic connections and validation responsibilities. An item list without these interfaces is not a complete line specification.
Packaging and storage interfaces
Specify whether the pitted purée or juice base is supplied as a chilled, frozen, otherwise treated or aseptically handled ingredient, as applicable to the developed product. Package material, closure, fill conditions and distribution are a connected system. Any claimed ambient stability or shelf life requires product- and package-specific validation; the process introduction does not set treatment temperatures or holding times.
Information for an engineering brief
- Test contrasting accepted stone-adhesion conditions and review skin retention against the intended juice or purée specification.
- Provide the intended finished-product specification, representative raw-material samples, daily operating pattern and seasonal peak load.
- Identify available utilities, factory layout, drainage, reject collection and the exact inlet/outlet conditions of equipment supplied by others.
- Agree trial acceptance criteria and define the preservation, filling, cleaning and commissioning responsibilities before finalising the equipment scope.
Quality, cleaning and separate streams
Quality observations
- Assess stone fragments, skin specks, colour, acidity and texture together. A change in variety should remain traceable through the trial and sample records.
- Define the sampling location, sample preparation, measurement method and acceptable variation. Retain traceable comparisons through the intended downstream route; a favourable immediate sample is not proof of storage stability.
Separate material streams
- Segregate stones and skin-rich rejects. Any proposal to recover more flesh from stones requires a separate fragment-control and product-quality assessment.
Cleaning and changeover
- Stone and skin residues can collect in different contact zones. Plan access to the destoner and refiner as well as cleaning of tanks and transfer lines.
- Assign cleaning responsibilities to the open preparation zone and the closed product circuit separately. Confirm which parts require removal or inspection and how cleaning effectiveness will be demonstrated with the actual product soil.
Plum and apple juice
Where this route differs from the site's primary line
An apple line separates extraction, clarity and concentration into different decisions. The same distinction is useful here: first define the edible feed and the product to be recovered, then specify any refinement, concentration and packaging. The sequence below describes this material rather than assuming that an apple press or clarification setting transfers unchanged.
Pits have to be managed before fine processing of stone fruit. Compared with an apple mill and press, define a positive stone-rejection boundary and decide whether skins belong in the purée.
Questions about this processing route
Can all plum varieties use the same pitting setting?
The setting should follow the accepted supply and a documented trial. Size, firmness and stone adhesion can change the separation result, so one demonstration does not establish every variety.
Is plum juice simply a thin purée?
The product descriptions should remain distinct. Juice separation and purée refining retain different fractions, which affects texture, recovery, transfer and the required downstream equipment.
What should a useful plum trial establish?
Test contrasting accepted stone-adhesion conditions and review skin retention against the intended juice or purée specification. Record incoming material, accepted feed, finished ingredient and each reject stream separately. Keep settings, samples and analytical methods with the trial record so the result can be compared with subsequent seasonal lots.
Technical reading and related materials
Define the line around your material
Include the incoming form, product target, quantity and measurement basis, package and known site interfaces in your enquiry. Describe this material explicitly in the project goal.
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