果汁中可溶性固形检测方案(折光仪)

京都電子工業株式会社KYOTO ELECTRONICSMANUFACTURING CO.，LTD.APRA-0232en APRA-0232en Application Note Measurement of Brix inFruit JuiceeUsingaRefractometer Industry：Food &beverageInstrument：RefractometerMeasurement method：Detection of critical angle of optical refractionStandards： 1. Scope Brix is defined as the mass percent concentration (%) of an aqueous sucrose solution. There is a.correlation between Brix and the refractive index， so the refractive index at 20 °C can beconverted to Brix using a conversion table built into the device. When the refractive index ofanaqueous sucrose solution with a known concentration is measured and then converted to the Brixvalue， it matches the sucrose concentration. This does not mean however that the Brix for actualsamples indicates their sucrose concentration. This is because samples contain acids such as citricacid and sugars such as glucose as soluble solids other than sucrose. The Brix obtained from thismeasurement is generally used as an indicator ofthe sugar content of fruit juices for exampleThis Application Note describes an example of the measurement of Brix for fruit juices using aKEM refractometer. Note that orange， grape， and apple juice were used as the measurementsamples. 2.Precautions After measurement is finished， use a paper wipe to remove the sample. Then clean the prismwith pure water， and dry it with a paper wipe. Clean it three times with pure water. Thenproceed to the next measurement. 3. Apparatus Refractometer 4.Reagents Cleaning solution： Pure water 5. Procedure -Sample preparation- 1) The juice is obtained by squeezing it out of the fruits. 2) If there is any skin， fiber， or other solids from the fruit in the juice， filter them out beforeusing the fruit juice as the sample. -Prepare to measurement- 1) Set the measurement temperature to 20°C. 2) Calibrate with air and pure water. (Calibrate each measurement day.) -Measurement- 1) Drop the sample using a dropper to ensure ample coverage of the refractometer prism. 2) Measurement. 6. Example of measurement The settings above are just one example. They may vary depending on the model， different parameters maybe added or different items may be added. —Measurement results — Table1 Results of Brix measurement of fruit juice(measurement temperature： 20°C) Refractive Brix Time Sample index (nD) (%) (s) 1 1.34778 9.97 35 Orange juice 2 1.34778 9.97 33 3 1.34778 9.97 36 1 1.35455 14.29 35 Apple juice 2 1.35455 14.29 34 3 1.35455 14.29 33 1 1.35817 16.55 35 Grape juice 2 1.35816 16.54 34 3 1.35817 16.55 34 9. Summary Good repeatability was obtained in the measurement results for each sample. The Brix value forfruit juices can be measured stably using a KEM’s refractometer. 京都电子工业株式会社-可睦电子(上海)商贸有限公司 电话：021-54488867 电邮： kemu-kem@163.com / 京都電子工業株式会社KYOTO ELECTRONICSMANUFACTURING CO.，LTD. 高精度数字式折光仪测定果汁中的可溶性固形含量使用日本京都电子(KEM)-高精度数字式折光仪/糖度计(RA-620)，测定橙汁、葡萄汁和苹果汁中可溶性固形物含量(糖度Brix%)的应用资料。