How does the freeze-drying process keep bulk longan matching the approved sample?
By fixing the five points where a longan ball is won or lost, and by proving the result on the lot itself before it sails. A sample looks good because someone chose good fruit and handled it with care. A container looks the same only when the fruit at the gate, the freezing speed, the dryer heat, the packing-room air and the facility are all held to the settings behind that sample. FruitBuys locks one qualified partner facility for your contract, runs every lot to the same settings, and sends you a pre-shipment sample (PSS) from the packed lot before the container is closed, with a retained sample kept for the lot’s full shelf life.
Why do bulk lots drift away from the sample?
Because a sample is a few hundred grams and a container is several tonnes. Most of the gap between them has one of four causes, and each one shows on the product:
| What changed | What you see in the container | Where it is controlled |
|---|---|---|
| Thinner, softer or less ripe fruit | Flat or torn balls, more breakage, weaker aroma | Gate: fruit grading |
| Slow freezing | Collapsed, wrinkled cups instead of round balls | Freezing |
| Too much dryer heat | Beige to tan colour, toasted smell, sticky surface | Drying |
| Humid air at packing | Balls that bend instead of crack; caking in the bag | Packing room |
| A different facility | All of the above, at once | Facility lock and change-control |
Every buyer should ask a supplier where each of these is controlled, including FruitBuys. The answers below are the settings behind every FruitBuys lot.
What happens between the orchard gate and the sealed bag?
Six steps, each with a setting that decides what you receive.
| Step | FruitBuys setting | What it protects for you |
|---|---|---|
| 1. Gate | Fully ripe Mekong longan at 18–22 °Brix, hand-sorted; split or soft fruit out | Thick aril, full honey-floral flavour, round shape |
| 2. Peel and deseed | By hand, aril kept whole around the seed cavity | Whole balls, not torn halves sold as whole |
| 3. Freeze | Blast-frozen at −35 to −40 °C until the core is below −30 °C | The round cup shape is set before any water leaves |
| 4. Dry | Sublimation below 0.5 mbar for 18–24 hours, shelf heat held at ≤50–55 °C | Sugar never softens or caramelises: ivory colour, crisp crack, fresh aroma |
| 5. Pack | Packing room at 20–24 °C and RH ≤35–40%; every batch bagged within 20 minutes of leaving the dryer | Balls go into foil at their release dryness, below aw 0.25 |
| 6. Inspect and seal | Grading against size and breakage limits; metal detection on every carton | No foreign metal; whole-ball grade within ≤10% broken |
Which of these are critical control points? In food-safety terms, one: metal detection, because a hazard there has no later step to catch it. The others are quality control points: they decide whether the lot looks, cracks and tastes like your sample. Both kinds are logged lot by lot, and the records sit in the technical file your QA team can audit.
Two steps deserve a closer look, because they are where longan is different from most fruit.
Freezing speed sets the shape. Longan aril is 83% water wrapped around an empty seed cavity. Frozen fast and hard, it stays a rigid cup and keeps that shape when the ice leaves. Frozen slowly, large ice crystals tear the flesh, and the cup collapses into a wrinkled shell in the dryer. A round, hollow ball in your bag is the visible proof that the freezer did its job.
Dryer heat sets the colour. Longan goes into the dryer at 18–22 °Brix, one of the sweetest fruits in freeze-drying. Above about 55 °C on the shelf, that sugar starts to soften and brown, and the lot drifts from ivory towards tan with a toasted smell. Holding the shelf at or below 50–55 °C costs dryer hours; it is also the reason a FruitBuys lot looks like its sample.
How does the approved sample become the reference for every container?
Through three samples, each with a job.
- Development sample. Sent in 3–5 working days for your R&D team: whole balls, halves and pieces if you want to compare. It shows what the fruit and the process can do.
- Pre-shipment sample (PSS). 100–200 g drawn from the packed lot itself, split into two sealed foil pouches with desiccant: one for sensory checks, one kept sealed for your laboratory. Sent by courier within 24–48 hours of packing, before the container is closed. You approve the lot you are buying, not a lot like it.
- Retained sample. Kept by FruitBuys from every container lot for its full shelf life, up to 24 months. If a question comes up after delivery, both sides test the same lot from the same seal.
| Approval stage | What you check | What it decides |
|---|---|---|
| Development sample | Colour, crack, aroma, ball size, taste in your recipe | Grade and specification |
| Trial order (1–2 full export cartons) | Same, at carton scale, plus water activity at receiving | Whether to sign a container programme |
| PSS from each packed lot | Match to the approved sample; lot COA and sulfite result | Release of that container |
| Retained sample | Re-test if needed after delivery | Fair answer to any claim |
Trial orders start from 1–2 full export cartons, with a free release QC log for moisture, water activity and sensory checks. Independent laboratory testing on a trial lot is charged at lab cost and credited in full against your first container.
What happens if something has to change mid-contract?
It is announced and re-approved before it reaches you. FruitBuys runs your contract in one locked partner facility. If a facility, cultivar or growing area ever has to change, FruitBuys tells you in writing first and sends a new PSS for approval before the changed lot runs. You keep audit access to the facility for the life of the contract, and certificate copies and registration numbers sit in the technical file before signing.
Seasons are not a change of specification. Main-crop fruit and rain-season fruit both release at ≤4.0% moisture and aw ≤0.25; what moves is how much fresh fruit it takes, which is covered in how many kilos of fresh longan make 1 kg of freeze-dried longan.
If your brand needs one cultivar on every lot, name it in the RFQ and FruitBuys confirms availability month by month before you sign. Tiêu Da Bò and Xuồng Cơm Vàng are both Mekong cultivars with thick, firm aril; where the cultivar matters less than continuity, leaving it open lets every monthly call-off run on the best fruit at the gate that month.
What should your QA team check on arrival?
Within 48–72 hours of devanning: crack, colour and aroma against the approved sample; water activity on a freshly opened bag; broken balls in 200 g against the ≤10% whole-grade limit; fines through a 3 mm screen. Report anything outside the specification within 14 days of devanning, or 30 days for laboratory results, and FruitBuys tests the retained sample alongside yours. The release limits behind those checks are in what moisture, water activity and COA freeze-dried longan should ship with, and how the bags and cartons protect the lot on the way is in how freeze-dried longan should be packed and loaded.
Production runs 20–30 days for a 20 ft container after deposit, so a programme with monthly call-offs keeps one lot in production while the previous one is on the water. The full specification is on the freeze-dried longan product page, and the freeze-dried longan RFQ checklist lists what a firm quote needs.
FAQ
How is longan freeze-dried?
Ripe Mekong longan is peeled and deseeded by hand, blast-frozen at −35 to −40 °C, then dried under vacuum below 0.5 mbar for 18–24 hours with shelf heat at or below 50–55 °C, and bagged in foil within 20 minutes in a dry packing room.
Why do some freeze-dried longan lots look brown or flat?
Brown or tan points to too much dryer heat caramelising the sugar; flat or wrinkled balls point to slow freezing. Both show on the sample, which is why the PSS comes from the packed lot.
What is a pre-shipment sample?
100–200 g drawn from the packed lot before the container is closed, in two sealed foil pouches: one for your sensory check, one sealed for your laboratory.
Will the container match the sample I approved?
Each lot runs to the same settings in the same locked partner facility, and you approve its PSS before it ships. A retained sample from every lot is kept for its full shelf life.
What is the critical control point in freeze-dried longan?
Metal detection on every carton is the food-safety critical control point. Freezing, drying and packing-room conditions are quality control points that decide shape, colour and crunch.
Does FruitBuys use X-ray inspection?
No. Every carton passes a metal detector before it is closed.
How long does production take?
20–30 days for a 20 ft container after deposit; development samples in 3–5 working days.
Can I audit the facility?
Yes. Audit access is part of every contract, and any change of facility is announced in writing and re-approved by PSS first.
