Sensory evaluation of vegetables? The procedures for quality identification of agricultural products generally include steps such as sampling, inspection, and grade determination. There are two main methods for identifying agricultural products, one is sensory identification method, and the other is physical and chemical identification method. The former is a method of identification with the help of sensory organs, and the latter is a method of identification with the help of various instruments and reagents.

(1) Sampling

Sampling is also called sample picking, sampling, etc. It is the first procedure for the inspection of agricultural and sideline products. The representativeness of sampling is closely related to the accuracy of test results. In order for the quality of the sampled samples to represent the quality of the entire batch of products, statistical principles must be followed to ensure that any one of the entire batch of products has a chance to be selected. Correct sampling and proper storage of samples are prerequisites for obtaining accurate inspection results.

When sampling, you must pay attention to the representativeness of the sample and comply with the following regulations:

When transferring agricultural products from other places, all documents of the batch of agricultural products should be reviewed, including the waybill and quality inspection certificate. , product inspection and inspection report form from the health agency, and then inspect it from the outside to the inside.

When it is found that poor packaging can affect the quality of agricultural products, the packaging should be opened for sampling and analysis. If the packaging is intact, part of the packaging can be opened and samples can be taken for inspection.

For agricultural products in small packages, 2 to 3 packages can be used as samples for inspection. The samples should be kept intact in the packaging, with instructions and trademarks attached.

A large amount of agricultural products, such as grains accumulated in piles or warehouses, should be sampled from the upper, middle and lower layers of the pile, mix the samples taken from each part evenly, and then use the "quarter method" to divide the two diagonal layers. The flaps are removed, and the remaining two flaps are remixed and sampled until the required amount is obtained. Agricultural products on ships should be sampled at five points in the shape of five plum blossoms, and then sampled according to the quartering method. For physical and chemical inspection, the samples should be ground, sieved into powder, and sent to the sample inspection room for testing.

The sampling of fresh meat depends on different purposes and requirements. Some can be sampled from different parts and mixed to represent the condition of the livestock. Some can be sampled from the same part of many livestock and mixed to represent a certain animal. The situation of one part.

For physical and chemical examination of fruits and vegetables, only the edible parts should be peeled and cored first. For small foods, such as pods, dates, grapes, hawthorns, etc., mix a large number of samples evenly, then use the quartering method to sample, and operate multiple times until the required amount (not less than 500 grams); for large agricultural products, such as Tomatoes, carrots, eggplants, watermelons, etc., should be sampled from multiple individual samples to eliminate differences between samples. The sampling method for physical and chemical testing is to cut a corner (longitudinal cut) from the corresponding surface of each sample to reduce internal differences.

Puffy, leafy vegetables, such as rapeseed, leeks, Chinese cabbage, etc., should be sampled from multiple separate samples (one basket, one bundle), and a certain amount should be taken respectively. The total amount taken should be within More than 1000 grams.

Sometimes to determine the degree of spoilage of agricultural products, you can also use its corrupted, contaminated or suspicious parts.

Agricultural products that are very different in terms of senses and properties should generally not be mixed together and must be packaged separately.

Try to maintain the original microbiological conditions and physical and chemical indicators of the sample so that it will not be contaminated or changed before testing.

All sampling tools, such as samplers, containers, and wrapping paper, should be clean. No harmful substances should be brought into agricultural products. Agricultural products used for bacterial testing should be strictly aseptic.

After sampling, it should be quickly tested or sent to a laboratory for analysis to avoid changes as much as possible.

Record the sampling unit, address, date, time, sample number, sample weight and packaging, sampling conditions and inspection purpose. (2) Sensory inspection

Sensory inspection uses human sense organs such as ears, eyes, mouth, nose, and hands to test the quality of agricultural products through vision, smell, taste, hearing, touch, etc. This method is mainly used to inspect the appearance structure, appearance defects, color, hardness, elasticity, smell, taste, sound, and packaging quality of agricultural products.

Sensory inspection is necessary for the quality identification of all agricultural products. This method is the most widely used in agricultural product inspection and occupies an important position. It can often determine the quality of its products, such as cotton, linen, tobacco, The inspection of agricultural products such as tea and livestock products is currently based on sensory inspection. The advantages of sensory testing are that it is fast, simple and easy to carry out, does not require complicated instruments and equipment, and has a certain degree of scientificity and accuracy. The disadvantage is that the test results cannot be expressed in specific numerical values.

It is greatly affected by the physiological conditions, work experience and external environment of the inspector, and has certain subjective factors.

Sensory inspection can be divided into visual inspection, olfactory inspection, taste inspection, tactile inspection and auditory inspection. The five methods of sensory inspection are often not used in isolation, but several methods are used comprehensively to comprehensively identify agricultural products. (3) Physical and chemical inspection methods

Physical and chemical inspection methods are methods that use various instruments, equipment, instruments and chemical reagents to identify the quality of agricultural products. It can detect the internal defects of agricultural products and determine the composition, structure and properties of agricultural products in depth. The identification results are more objective and precise than sensory identification and can be expressed by specific numerical values.

With the development of science and technology, various new identification methods and detection methods are constantly being widely used. There are more and more types of physical and chemical identification methods, their application scope is getting wider and wider, and they are more accurate in identification. The performance, sensitivity and stability are constantly improving, and it is increasingly developing in the direction of fast, less loss (or lossless) and automation. However, physical and chemical testing methods are generally not as quick and easy as sensory testing, and require certain instruments, equipment, reagents and operating techniques.