The Effect of Fatty Acid Value of Rice on Storage Time?

The Effect of Fatty Acid Value of Rice on Storage Time?

The fatty acid value of rice grains shows a significant increasing trend with prolonged storage time. The patterns of change and influencing factors are as follows:

‌Correlation Between Fatty Acid Value and Storage Time‌

‌Initial Stage‌: Freshly harvested rice has a lower fatty acid value: indica rice ≤30 mg KOH/100g (dry basis), japonica rice ≤25 mg KOH/100g (dry basis).

‌Annual Increase‌: In South China, the fatty acid value of rice increases by about 10 mg KOH/100g per year. For example, after 1 year of storage, early indica rice averages 32.5 mg KOH/100g, while japonica rice reaches 28.0 mg KOH/100g.

‌Long-Term Storage‌: Poor storage conditions (e.g., high temperature and humidity) can rapidly raise the fatty acid value to over 50 mg KOH/100g, entering the range of severe unsuitability for storage.

‌Key Influencing Factors‌

‌Temperature and Humidity‌: High temperature and humidity accelerate fatty acid oxidation, with a positive correlation between fatty acid value and temperature/humidity. Low-temperature storage (e.g., 0°C) can significantly inhibit its rise.

‌Mold and Broken Grains‌: Mold activity and increased broken grains promote fatty acid generation, leading to quality deterioration.

‌Regional Differences‌: Due to humid and hot climates, southern regions generally see faster fatty acid value increases than northern areas.

‌Storage Quality Assessment Standards‌

‌Suitable for Storage‌: Indica rice ≤30 mg KOH/100g, japonica rice ≤25 mg KOH/100g.

‌Unsuitable Threshold‌: Indica rice >37 mg KOH/100g, japonica rice >35 mg KOH/100g.

‌Rapid Detection Method‌: The colorimetric test for rice freshness (light green is optimal) can assist in judging storage duration.

ST-59 Corn Grain Fatty Acid Value Titration Tester is a full-automatic grain fatty acid value tester, which is an automatic titration device based on the color change of titration end point. It is mainly used to measure the fatty acid value of rice, brown rice, rice and other grains. The fatty acid value tester realizes the automation of titration end point determination, measurement, data processing, determination result display and printing, and improves the objectivity and accuracy of the detection results.