Corn quality inspection method! Attachment: corn grade distinction

August 22, 2020

In the season of corn acquisition, how do you know the level of corn? Do you know how much corn can be sold?

New corn characteristics and corresponding control points

1. High moisture and unevenness . The newly harvested corn is generally 15%-20% in North China, and generally more than 20% in Northeast China and Inner Mongolia. The excessive moisture is prone to mildew and heat, which is not conducive to storage. At the same time, it will increase the moisture of feed products and destroy the feed diet. Active ingredients such as vitamins, lowering the level of metabolic energy and crude protein in the diet, breaking the balance between nutrients in the diet, etc. When the moisture content of corn is 1% higher, the energy-protein ratio is 0.5%, and the energy-amino acid ratio is 0.5%. , that is, the nutritional value differs by 0.5%. Therefore, the water standard at the time of acquisition can be reasonably formulated according to the storage situation of the corn storage in the warehouse.

At the time of acceptance, the five-point method can be used for sampling and mixing, and it is suspected that the local moisture is high and can be sampled and tested separately. It can also be taken with the unloading process.

Sensory detection method: use nail nails to corn part, soft and wet water is generally higher than 14% or even higher than 16%, hard or dry, the water is lower; biting corn with teeth, brittle hard water is low, otherwise High moisture.

Instrument testing: Generally use a grain moisture detector. When measuring the moisture of corn, the grain moisture meter should pay attention to the temperature difference between morning and evening and the temperature difference between indoor and outdoor. When the temperature difference is too high, the instrument error is very large, and it can be placed indoors and then tested when sampling. At the same time, the test data of the calibration grain moisture meter is measured by the oven method fixed 2-3 times a week to update the data.

2. There are many broken grains and high impurities . The new corn has a short drying time and a high humidity. When the mechanical threshing, the corn kernels and the corn kernels are easily broken into the corn, and the impurities such as sand can reach about 5% or even higher. Damage to the tire rolling forklift during transportation also results in more broken particles. Impurities mixed into the corn occupy the active constituents of the corn, and impurities are filled in the gaps of the corn to affect the ventilation and ventilation, and the broken parts increase the chance of mildew.

Note: granules and impurities are usually deposited on the bottom of the car. Sampling brazing is difficult to obtain and can be sampled multiple times during unloading. Most corn grits are screened by corn drums into large or small grains. Don't throw them, don't throw them, don't throw them (important things say three times)! It is for ruminants. It is a very good feed with high economic value and can also be fed on poultry.

3. Mildew is low . At present, the rate of mildew detected in the acceptance of new corn is relatively low, generally not exceeding 2%. Mildew is not only caused during storage, but may be infected with mold in the field, so it is divided into storage mold and mold.

Samples were mixed for four minutes after testing for mildew. After screening and removing impurities, they were placed in a white enamel pan and picked from left to right. Don't underestimate this white plate. The color of the corn granules on a white background is very clear. The mildew and broken granules are clear at a glance, and the granules are not easy to roll out. After the test, the corn sample can be directly poured from the corner of the porcelain plate for centralized treatment.

Mildew detection currently has two kinds of methods and weighing methods:

The number of grains method: the corn sample particles should not be too small, according to the weight of corn 1000 grains, about 300-400g, the small series recommended 500g, not less than 400g.

Weighing method: compare the average grain weight (or 1000-grain weight) of mildew and normal grain, the same number of particles, we found that the mildew particles are lighter, the ratio of the two is between 0.7-0.8, the mildew particle weighing method is After the corn is mixed, the corn is weighed and mixed, and then placed in a white enamel pan, and the moldy granules are weighed and weighed by the total weight and 0.75 as the mildew rate.

Sensory detection method: randomly grab a handful of corn (a handful of corn does not exceed 100 capsules), a few mildews, more than two mildew particles can be directly returned. This method can also be used for corn self-tests by retail suppliers.

4. The difference in bulk density is large . The regional differences, variety differences, and planting season differences in corn planting in China lead to a large gap in bulk density. Spring maize is full of maturity due to its maturity.

Pay attention to the selection of the appropriate grain cylinder when the weight detector is inspected. The grain cylinder is required to be clean and free of debris. Before use, it is required to zero the load. The sample can only be flattened when it is full, and it cannot be pressed. The speed of pulling out the insert is appropriate.

The cylinder method should pay attention to the corn sample to be placed in the measuring cylinder at a constant speed. When the sample is near 1000ml, the sample should be placed in a small amount until the total amount of the sample is adjusted to the mark line. Multiple detection averaging can reduce the test error.

How to distinguish corn grade?

There are three national quality standards for corn in China, namely the most basic corn national standard, the national standard for corn for feed and the national standard for industrial corn. These three standards are both interconnected and characteristic. The corn national standard is a general standard for bulk corn and is widely used in the acquisition, storage, transportation, processing and sale of commercial corn. The feed corn standard and the industrial corn standard are more targeted, and there are some changes and adjustments based on the corn national standard.

The commonality of these three standards is that water, impurities, imperfect grains, and moldy grains are the main indicators for measuring the quality of corn. The difference is that the corn used in feed, in addition to the main indicators such as the retention weight, also increases the crude protein. A technical indicator, while industrial corn has abandoned the bulk weight of this indicator item,

In general, bulk density, impurities, moisture, imperfect grains and moldy grain indicators are the most basic and most important indicators for measuring corn quality, and are widely representative and authoritative.

The following differences in the quality of corn in different producing areas in China :

(1) Bulk weight

In normal years, the weight of corn in Northeast Inner Mongolia is the highest, the quality of Tongliao and Chifeng corn is basically second-class, 90% in the first-class; 70% in Jilin corn is second-class; the quality of corn in Heilongjiang is generally, 60%-70%. Can reach the third class; 50% of Liaoning corn can reach second class, 80% can reach third class. However, the bulk density of corn is greatly affected by the annual situation. For example, due to the weather, the moisture of corn is large and the weight is reduced.

In normal years, the corn in North China's Shandong and Hebei provinces are basically second-class, especially in the northwestern part of the mountain and north of Xingtai, Hebei.

(2) Moisture

In normal years, the moisture in the northeast region is 28%-30% when harvested, and the highest is 35%-40% when the year is not good. The moisture of Inner Mongolia corn is slightly lower, generally around 24%, sometimes reaching 27%-28%.

Due to the cold winter weather in Northeast China, the proportion of naturally drying corn is small. Except for Tongliao in Inner Mongolia and southwest Liaoning, most of them are dried corn. Drying mainly adopts two methods. One is to directly dry to about 14.5%. During the storage process, the water gradually loses to less than 14%; the second is to dry to about 20% of moisture, and then dry. The corn marketed before the Spring Festival in Northeast China mainly adopts the first method. Due to the excessive precipitation, it is easy to cause corn kernels to have a low hair density and a low bulk density.

Our Corn Gluten Additives:Corn Gluten Feed 18%;Corn Gluten Meal 60%;Distillers Dried Grains with Solubles 26%