GB/T 34790-2017 in English
VALIDInspenction of grain and oils-Determination of water activity of grains- Instrumental method
- Issued on:2017-11-01
- Implemented on:2018-05-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$156.00
《GB/T 34790-2017粮油检验 粮食籽粒水分活度的测定 仪器法》由TC270（全国粮油标准化技术委员会）归口，TC270SC1（全国粮油标准化技术委员会原粮及制品分会）执行，主管部门为国家粮食和物资储备局。
Introduction
National Standard of the People's Republic of China GB/T 34790—2017
Instrumental method for the determination of water activity of grain kernels in grain and oil inspection
Background of standard formulation and analysis of technical evolution
Water activity is an important indicator for measuring the free water content in grain kernels, which directly affects storage stability, germination rate and processing characteristics. This standard was proposed by the State Administration of Grain to standardize instrumental determination methods and ensure the accuracy and reliability of the results.
| Item | Wheat | Rice | Soybean | Corn |
|---|---|---|---|---|
| Average water activity | 0.362 1 | 0.362 5 | 0.362 0 | 0.365 1 |
| Repeatability limit r | 0.002 8 | 0.004 2 | 0.004 2 | 0.003 6 |
| Reproducibility Limit R | 0.025 8 | 0.023 5 | 0.021 6 | 0.017 9 |
Instrument and Reagent Requirements
Water Activity Meter should have high resolution (≤0.0015aw) and low measurement error (≤0.010aw). It is recommended to use a temperature-controlled instrument to ensure that the temperature deviation is within ±0.5°C.
Implementation Recommendations
Case Study: Calibration and Maintenance of Water Activity Meters
Regularly calibrate the instrument using standard solutions (such as sodium chloride and potassium sulfate solutions) to ensure measurement accuracy. It is recommended to check sensor performance quarterly and record calibration results for traceability.
Summary
GB/T 34790—2017 provides a scientific and accurate method for determining water activity, which is of great significance for ensuring grain storage safety and processing quality. It is recommended to strictly follow the standard requirements in actual operations to ensure the accuracy and reliability of data.
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