GB/T 5502-2025Inspection of grain and oils - Determination of milling degree of rice and other grain kernels (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents". Drafting. This document replaces GB/T 5502-2018 "Grain and Oil Inspection. Rice Processing Precision Inspection". Compared with GB/T 5502-2018, except for the following. Aside from structural adjustments and editorial changes, the main technical changes are as follows:

---The scope of application has been changed (see Chapter 1, Chapter 1 of the.2018 edition);

---Added terms and definitions for the processing precision of milky white grains and millet (see 3.3, 3.4);

---Added a description of the principle of the direct observation method (see 4.4);

---Reagents and materials have been changed (see Chapter 5, Chapter 5 of the.2018 edition);

---The shelf life of the staining stock solution and staining agent has been increased (see 5.5, 5.6);

---The instruments and equipment have been changed (see Chapter 6, Chapter 6 of the.2018 edition);

---The eosin-gamma-methylene blue staining method has been modified (see 8.1.1,.2018 version 8.1);

---The instrument-assisted detection method and its result interpretation have been deleted (see sections

9.1.2 in the.2018 version);

---Added inspection methods for the processing precision of sorghum and millet (see 8.2, 8.3);

---The representation of rice processing precision results has been changed (see 9.1.3,

9.2 in the.2018 version);

1 Scope

GB/T 5502-2025 is the Chinese national standard covering the milling degree of rice - the residual bran on the kernel judged by staining or by comparison with reference samples, which decides both the grade and, incidentally, how much of the nutrition was polished away. Issued on 31 October 2025, it has been in force since 1 May 2026, replacing GB/T 5502-2018.

This document describes a method for inspecting the processing accuracy of rice. This document applies to the inspection of the processing precision of rice, sorghum, and millet.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included. For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies. This document. GB/T 1354 Rice

GB/T 5491 Sampling and Divided Sampling Methods for the Inspection of Grains and Oils

GB/T 6682 Specifications and test methods for water used in analytical laboratories

GB/T 11766 Xiaomi LS/T 3215 Sorghum Rice LS/T 15121 Standard Sample for Precision Milling of Indica Rice LS/T 15122 Standard Sample for Processing Precision of Indica Rice Suitable for Milling LS/T 15123.1 Standard Sample for Fine Milling of Japonica Rice LS/T 15123.2 Standard Sample for Processing Precision of Japonica Rice

3 Terms and Definitions

The terms and definitions defined in GB/T 1354, GB/T 11766, and LS/T 3215, as well as the following terms and definitions, apply to this document.

3.1 Image acquisition The process of acquiring images of samples and converting the image information into information that the system can recognize.

3.2 Image analysis The process of using mathematical methods to determine and analyze the acquired image information.

3.3 Milky white particles undermiledkernel The pericarp has been mostly removed, and the seed coat has been removed to remove more than two-thirds of the whole sorghum grain.

3.4 The degree to which the outer layer of the millet has been removed.

Note. The percentage of millet grains in the sample with the outer skin layer basically removed is expressed.