Grading and Packaging of Walnuts

   1, nut grading standard and packaging and drying walnut nuts should be graded, because the quality of walnut nuts is deeply concerned by producers, operators, consumers and foreign trade departments, so the quality of different nuts has different prices. The quality grade of walnut can be divided into four grades: special grade, first grade, second grade and third grade. Each grade requires that the nuts are fully ripe, the shell surface is clean, the suture is tight, and there is no kernel, moth, oil, mildew, peculiar smell, no impurities and no harmful chemicals.

   (1) Super walnut has uniform shape, uniform shape, natural yellow and white fruit, full kernel, yellow and white color and light astringent taste; nut diameter is not less than 30mm, average single fruit weight is not less than 12.0g, kernel yield is 53%, empty fruit rate is not more than 1%, damaged fruit rate is not more than 0.1%, moisture content is not more than 8%, no black spot fruit, easy to take whole kernel. The content of crude fat is not less than 65%, and the quality of protein is 14%.

The fruit shape of    (2) grade 1 walnut is basically the same, with a kernel yield of 48%, a shell fruit rate of no more than 2%, and a black spot fruit rate of no more than 0. 1%, other indicators are the same as the super fruit index.

   (3) second-grade walnut has the same fruit shape, natural yellow-white shell, full kernel, yellow-white color and light astringent taste; nut transverse diameter is not less than 30mm, average single fruit mass is not less than 10g, kernel yield is 43%, shell fruit rate is not more than 2%, damaged fruit rate is not more than 0.2%, moisture content is not more than 8%, black spot fruit rate is not more than 0.2%, and half kernel is easy to take. The content of crude fat is not less than 60%, and the content of protein is 12%.

   (4) Grade III walnut has no fruit shape requirements, the outer shell is naturally yellow-white or yellow-brown, the nuts are fuller, yellow-white or light amber, slightly astringent; the transverse diameter of nuts is not less than 26mm, the average single fruit weight is not less than 8g, the kernel yield is 38%, the empty fruit rate is not more than 3%, and the damaged fruit rate is not more than 0. 3%, moisture content not more than 8%, black spot fruit rate not more than 0. 5%. 3%, easy to take 1 stroke 4 kernels; crude fat content not less than 60%, protein content up to 10%.

After    grading, walnut nuts should be packed in dry, strong, clean and hygienic gunny bags, each containing about 45kg. The mouth of the bag is sewn tightly with needle and thread, and the batch number is marked on the upper left corner of the bag. Walnuts whose nuts are thinner than 1mm can be packed in cartons. In the process of transportation, rain, pollution and severe collisions should be prevented.

   2, nucleolus grading standard and packaging

   (1) there are two kinds of walnut kernel extraction: manual kernel extraction and mechanical kernel extraction. The method of manual smashing is often used in our country. Walnut kernels are divided into dry smashing and wet smashing. The so-called dry smashing means that the walnut is fully air-dried to reduce moisture (usually less than 5%), and then begins to smash the kernel. This kind of walnut kernel, which is dry and white, is commonly known as "ballooning", which is crisp and shiny as a good product, and is welcomed by foreign customers. The so-called "wet smashing" is to smash walnut kernels without waiting for walnut moisture to decrease. Wet smashing walnut kernel, the mouth is dark, with a similar oil phenomenon, not brittle and gray no choice, commonly known as "ballast". This kind of walnut kernel spoils easily. However, due to storage and other reasons, dry smashing kernels with oil production at the ballast mouth is not this case. When smashing the kernel, you should pay attention to placing the suture parallel to the ground, force should be uniform, do not hit hard and repeatedly, and get the whole kernel as much as possible. In order to reduce the contamination of the nucleolus after the nut is smashed, the site must be cleaned up before smashing the kernel, and the site should not be smashed directly on the ground. after the nut is broken, it is put into a clean basket or stacked on plastic sheeting, and then the nucleolus is stripped off. When stripping kernels, it is best to wear clean gloves, put the stripped nucleoli directly into a clean container or plastic bag, and then pack them by grade. The mechanical crushing machine is usually used to crush the core, and the efficiency is much higher than that of manual crushing. Take Australia as an example, its mechanical kernel extraction is an assembly line production operation system, including nut grading, guidance, extrusion and breaking, kernel separation, nucleolus grading packaging, etc., which greatly improves the grade and efficiency of walnut kernel.

   (2) nucleolus grading standard and packaging

   divides walnut kernels into eight grades according to their color and completeness. In industry terminology, "grade" is called "road".

   Whitehead Road: 1 Compact 2 kernels, light yellow

   White Road 2: 1 gamble 4 kernels, light yellow

   White third Road: 1Compare 8 kernels, light yellow

   shallow road: 1 stroke 2 kernels, light amber

   light second road: 1 ram 4 kernels, light amber

   light third way: 1 ram 8 kernels, light amber

   mixed four ways: broken kernels, light and uniform nucleoli

   deep three ways: broken kernel, dark nucleolus.

   in walnut kernel classification, in addition to pay attention to the size and color of nucleoli, but also require nucleolus dry, thick, full, no moth, no mildew deterioration, no peculiar smell, no impurities. For different grades of walnut kernels, the export price is different, the white head road is the highest, the shallow head road is the second, but there are not many nucleoli that fully meet the above two types. A large number of nucleolus products exported from China are four grades: White second Road, White third Road, shallow second Road and shallow third Road, and the nucleoli of mixed fourth Road and Deep third Road are used for domestic sale and processing.

   walnut kernels are usually packed in cartons or wooden cases. The wood in the wooden case of packing nucleolus should not have a peculiar smell. Generally, the net weight of each box of nucleolus is 20,25kg. Moistureproof measures should be taken when packing, such as cellophane at the bottom and around the box, and immediately sealed and bundled for years after packing. And indicate the weight, grade and address, etc.