Raw cashew nut In order to obtain the highest quality cashew kernels to be shipped, cashew processors search for high-grade raw cashew nuts. A number of standards, including color, shape, brightness, and exterior aspect, can be used to describe the quality of raw cashew nuts.
The quality of the kernels inside the shell, though, is what really counts. while characteristics like color, shape, and brightness remain constant, the size of the kernel inside the shell varies.
The methods employed include Nut count, Out Turn (Kernels Output Ratio), Moisture, and Total Defective Nuts to measure the size of the kernel inside the shell.
Systematically it will guide you to know about raw cashew nuts and how to check quality.
Which parts of the fruit of the raw cashew tree are usable?
01 - The Kernel
- It is mainly consumed roasted and salted. Crushed kernels are used in the food industry (chocolate factory, pastry factory, biscuit factory). The oil obtained from kernels is used in cosmetic products or in food preparations.
02 - The Balm
- It is also called Raw Cashew Nut Shell Liquid (CNSL) and has several uses in the industry. Extracted from the shell, this liquid is mostly composed of anacardic acids. It is used, after purification, in chemical products manufacturing. This liquid is dangerous, as it cannot be handled with bare hands. Its handling requires the use of gloves.
03 - The Apple
- It is juicy, lightly flavoured, sour and contains vitamin C.
- This apple is edible.
- Juice can be extracted from the raw cashew apple to produce alcohol, vinegar and syrup.
04 - The Shell
- It is used as a fuel to drive the nuts processing (cooking or drying).
05 - The Peel or Testa
- It is sometimes used either like the shells or as a complement livestock food, it can also be used to produce dyeing.
What is needed for performing the test?
How to take a mother sample?
We see a truck unloaded at a harbour. During the unloading of the truck, nuts are taken from the bag with a catheter bag…
How many samples must be taken to be sure of the representativeness of the Result?
This depends on the size of the lot, meaning the number of bags to be examined.
| Lot Size (No. of bags) | No. of Bags to be sampled | No. of Samples |
|---|---|---|
| 1 – 10 | All | 1 |
| 11 – 100 | 10 | 1 |
| 101 – 500 | 50 | 2 |
| 501 – 1000 | 10% (50 – 100) | 3 |
| Over 1000 | 8% (80) | 5 |
How to take a sample from different lots
Step 1
Taking “Mother” Sample
Put collected nuts in a pile on a flat surface
Step 2
To Be Followed With Mother Of Sample
Taking a sample of the collected nuts
Mix the “mother sample”
Separate into quarters
Step 3
To Follow Under These Steps
Assemble the samples to be analysed
Take one kilogram of nuts from the first of the two samples constituted
Four kilograms of nuts should be taken from the last stage of the procedure.
How to use four KGS sample?
- The first kilogram is used to check the floating method to determine how many nuts are floating.
- The final three kilograms are used to assess the raw nut yield and calculate the average cutting result...
Floting raw cashew test is one method used to verify more about raw cashew nuts.
Some Peculiar Facts about Raw Cashew Nuts
- Raw cashew nut grows with the fruit but outside the fruit.
- Most raw cashew nuts sink in the water but 10-30% nuts float in the water. These floating nuts are called floats and sunk nuts are called ‘nil’ or ‘nil floats’. Nil floats always give the best out-turn of the area but the floats will have some unripe nuts, low out-turn nuts and may have some good nuts because of air content.
- If floats are dried under the summer sunlight and then put in water, 25-35% of floats would sink to the bottom but would eventually float.
Check the ‘Raw cashew nuts’ moisture content.
- After drying, a moisture level must be maintained between 7 and 8%.
- Moisture level greater than 10% exposes nuts leads to fungus growth.
- If the nuts contain a moisture level of below 6%, they become overly dry and fragile during processing.
Calculation of Nut Count (NC)
Place the nuts into small stacks of ten.
| Number of nuts per kg | Quality assessment |
|---|---|
| Lower than 180 | Excellent |
| [180-190] | Very good |
| [190-200] | Good |
| [200-210] | Average |
| [210-220] | Very average |
| [220- 230] | Just acceptable |
| Beyond 230 | Poor |
How to open the nuts
Using the cutter, all of the nuts in the sample are split lengthwise into two halves, either with or without defects.
To investigate the nature of the kernel, the split nut is inspected in bright light.
Check the kernel output ratio (LBS.)
By observing the split nuts, we can observe the kernels and classify them into three categories.
Wholesome kernels (100 percent accepted)
Good kernels
Kidney-shaped kernels that are fully developed and edible in their completely
50 percent rejected kernels
100 Percent rejected kernels
After having determined to which category each kernel belongs to, what next?
The kernel is removed from the shells with the help of the scooper, preferably without removing the peel or testa.
The different kernels are put in marked bowls, one for each Grade.
When finished segregating the kernels, what needs to done then?
All different kernels are weighed separately with an electronic balance and the weight is recorded.
Note: Dust, external material and nut count do not affect the out-turn. They are just used to give an idea of the amount of impurities and quantity of bigger or smaller nuts in a sample.
How to calculation "Out-turn"
First the amount of total useful calculation then done? kernels is calculated as a sum of the weight of all good kernels plus a part of the weight of the dotted kernels and premature kernels.
Then, a standard factor (of
needs to be done? 0.176) is applied to this result to convert it into the internationally recognized unit of Lbs quality.
Testing for Defective Nuts
It is done by cutting test using a 1 kg sample of nuts along the natural line of cleavage and all with non-defective kernels shall be segregated without removing the kernels from the shells into the same categories as for out-turn.
- In practice 0 to 15 % max. of defective nuts is acceptable= Standard grade
- 16 to 24 % max. of defective nuts is acceptable but is under grade
- Over 24 % is not acceptable and rejected
Yield as a function of KOR
| RCN Outturn Lbs | Ker output de-shelling % | Ker output after Oven 5% | Ker output After Peeling 10% | Ker output After Grading 2% | Ker output in Packing |
|---|---|---|---|---|---|
| 45.00 | 25.57% | 24.29% | 21.86% | 21.42% | 21.42% |
| 45.50 | 25.85% | 24.56% | 22.10% | 21.66% | 21.66% |
| 46.00 | 26.14% | 24.83% | 22.35% | 21.90% | 21.90% |
| 46.50 | 26.42% | 25.10% | 22.59% | 22.14% | 22.14% |
| 47.00 | 26.70% | 25.37% | 22.83% | 22.38% | 22.38% |
| 47.50 | 26.99% | 25.64% | 23.08% | 22.61% | 22.61% |
| 48.00 | 27.27% | 25.91% | 23.32% | 22.85% | 22.85% |
| 48.50 | 27.56% | 26.18% | 23.56% | 23.09% | 23.09% |
| 49.00 | 27.84% | 26.45% | 23.80% | 23.33% | 23..33% |
| 49.50 | 28.13% | 26.72% | 24.05% | 23.57% | 23.57% |
| 50.00 | 28.41% | 26.99% | 24.29% | 23.80% | 23.80% |
| 50.50 | 28.69% | 27.26% | 24.53% | 24.04% | 24.04% |
| 51.00 | 28.98% | 27.53% | 24.78% | 24.28% | 24.28% |
| 51.50 | 29.26% | 27.80% | 25.02% | 24.52% | 24.52% |
| 52.00 | 29.55% | 28.07% | 25.26% | 24.76% | 24.76% |
| 52.50 | 29.83% | 28.34% | 25.50% | 24.99% | 24.99% |
| 53.00 | 30.11% | 28.61% | 25.75% | 25.23% | 25.23% |
| 53.50 | 30.40% | 28.88% | 25.99% | 25.47% | 25.47% |
| 54.00 | 30.68% | 29.15% | 26.23% | 25.71% | 25.71% |
General Quality Standards Specifications
Raw Cashew Nuts
- Reasonably dry: about 8 – 10% moisture content.
- Kidney shaped
- Colour - gray, dark grey, greenish or brownish in colour.
- Healthy nuts (free from mould, etc)
- Free from foreign matter (max 0.5%) by weight (e.g. stones, leaves, metal piece, etc).
- Max 15% defective
Kernels
- Reasonably dry (max 5% moisture content)
- Kidney shaped
- White or scorched or dessert kernels in the form of wholes or pieces
- Completely free from infestation, adhering testa and objectionable extraneous matter
- Max 0.7% fatty acid content
