Walnut harvesting and processing points
Hebei Green Ridge Fruit Industry Co., Ltd. Jia Zhihua Ding Fengmei
With the continuous expansion of the walnut tree planting area, walnut trees in some areas began to produce results, a certain amount of output, timely harvesting of walnuts, blue peel processing work, directly affect the quality of walnut nuts, thus affecting sales. Therefore, to grasp the Hong Ling walnut Harvest time and post-harvest processing technology. Now I introduce some of my experiences as follows:
Yi Xiangling walnut harvest time
Harvesting walnuts is very important. Premature green peeling is not easy to peel, the seed is not full, the kernel rate and oil yield are low, and it is not resistant to storage. If the fruits are harvested too late, the fruit will easily fall off. At the same time, the time for the green peeling to remain on the trees will be too long. This will increase the chance of infection by molds and lead to the deterioration of the quality of the nuts.
The ripening period of walnut fruits varies according to species and climatic conditions. Early and late maturing varieties can differ by 10 to 25 days in maturity. In general, the maturation period in the northern region is in the early to mid-September period, and it is relatively early in the south. The maturity of the same variety in different regions varies, such as the Xiangling variety matured in early September in Xingtai and matured in early September in Shandong. The maturation period in the same area is also different. The plain area matures earlier than the mountain area, the low mountain level matures earlier than the high mountain position, and the sunny slope matures on sunny slopes. The drought year is earlier than the rainy year.
The appearance and morphological characteristics of mature walnut fruit are: the green skin turns yellow from green, and the top part is cracked, and the green peel is easy to peel. The internal features at this time are: full kernels, mature young embryos, hardened cotyledons, and strong aromas. This is the best time for fruit harvesting. There are many varieties of large walnut gardens, and they are harvested according to the harvest time of different varieties, and one species is harvested before another. According to different varieties and different periods of harvest. At present, most of the harvesting in production is early and attention should be paid.
Second harvest method
Walnut harvesting generally adopts manual harvesting method and mechanical vibration harvesting method.
(1) Manual harvesting method When the fruit is ripe, hit the branches where the fruit is located or directly touch the falling fruit with a bamboo pole or an elastic wooden pole. This is the current method commonly used in China. The technical point of this law is that when it is struck, it should be carried out from the top to the bottom and from the inside to the outside, so as not to damage the shoots and affecting the yield for the following year.
(2) mechanical vibration harvesting method before harvesting 10 to 20 days, sprayed on the tree 500 ~ 2000 ppm ethephon ripening, and then mechanically shaking the trunk, so that the fruit fell to the ground. The advantage of this method is that the green peel is easy to peel off and the fruit surface is lightly polluted. However, its disadvantage is that due to the use of ethephon ripening, it often causes a large number of leaves to fall off and weaken the tree. This is less used in France and some conditions cannot be achieved. In addition, it is easy for the leaves to fall off, and the buds will germinate in the year and affect the next year's yield and the safety of the tree.
Three walnut peeling and drying tips
1 Take off the skin
1) Stacking and peeling is a traditional method of walnut peeling in China. The technical point is that the fruit should be transported to the outdoor cool place or indoors in time after harvesting, and should not be exposed to sunlight, and then piled at a thickness of about 50cm (too thick and perishable). If a layer of hay or dry leaves with a thickness of about 10 cm is added to the fruit heap, the temperature inside the heap can be increased, the fruit ripening can be promoted, and the speed of peeling can be accelerated. Generally stacking 3 to 5 days, when the peel from the shell or cracking of more than 50%, you can use the stick percussion peeling. For unpeeled people, they can be stacked for several more days until they are fully peeled. Do not blacken, or even rot, the husks during stacking so as not to infiltrate the husks into the shells to contaminate the kernels and reduce the quality and value of the nuts.
2) Decontamination of pharmaceutical agents The dehulling method due to stacking and peeling has a long time, low work efficiency, high fruit contamination rate, and has a greater impact on the quality of nut products. Since the 1970s, some units have begun trials of ethephon ripening and peeling techniques. The specific approach is: after fruit harvesting, dipping in a concentration of 0.3% to 0.5% ethephon solution for about half a minute, and then piled in a cool place or room at a thickness of about 50cm, at a temperature of 30°C, relative humidity 80% to 95% of the conditions, after about 5 days, the peel rate can be as high as 95%. It can be peeled off in about 2 days. The duration of ethephon ripening and the concentration of drug used are related to fruit maturity. The fruit has high maturity, low drug concentration, and short ripening period.
3) Dehulled skin is generally treated manually or mechanically.
2, nut flush
After the walnuts have been peeled off, if the nuts are sold as a commodity, they should be washed with clear water first, to remove dead skin, dirt, and other contaminants from the surface of the nuts. To improve the appearance of nuts and the value of goods.
Washing method: Put the peeled nuts into the basket, put the baskets in the sink, and stir it with a bamboo broom. It is better to use a running water type or increase the number of rinses. Thin-skinned walnuts are not bleached. Maintain the original flavor. The nuts used for seeding need not be washed and bleached after peeling, but can be dried directly and stored for later use.
3, drying
After the general nut rinsing, the natural drying method and the fire burning drying method can be adopted, and the conditional production area can be dried using a walnut nut dryer.
(1) The natural drying method The washed nuts can be dried on bamboo foil or sorghum stalk foil for a long time. After most of the water evaporates, they are then spread out on the dry mat or bamboo foil to dry, and they must not be exposed to sunlight to prevent the core shell from cracking. , nuclear deterioration. The thickness of the nuts should not be more than 2 layers in order to prevent the backlight of the kernel from turning yellow. Take care to avoid rain and damp at night. General sun 5 to 7 days can be. Criteria for judging the dryness is that the nuts hit a knocking sound and the diaphragm is easy to smash by hand. The skin color of the seed is changed from milky white to light yellow-brown, and the moisture content of the seed does not exceed 8%.
(2) When the fire burning method is used for autumn rain, it can be dried by fire. The thickness of the nuts to be distributed is not more than 15cm, which is too thick for inconvenience, baking is not uniform, and wet coke is easy to appear; too thin to scorch or crack fruit. Baking temperature: baking room temperature is 25 to 30°C Degree, but to open the skylight, drain water vapor. When the roasting is completed, the sunroof is closed and the temperature is raised to 35-40°C. When the temperature reaches 70-80%, the temperature is lowered to about 30°C; Turning moderation: After the fruit is lifted to a large amount of water vapor, it is not appropriate to turn the fruit; after baking and baking for 10 h (hours), the surface of the shell can turn without water. The final stage is flipped every 2 hours.
(3) Drying the dryer.
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