(GTN 3700)
PRACTICAL 2: DETERMINATION OF SOLUBLE SOLIDS CONCENTRATION USING HANDLED REFRACTOMETER
Name: Noor Fareeza Juliana Bt. Abd. WahabMatric No.: UK32565
Program: Bac. Sc. Agrotechnology (Postharvest Technology)
Group: 8
INTRODUCTION
The major soluble solid in fruit juices is sugars, so the soluble solids can be used as an estimate of sweetness. Soluble solids concentration measurement in the flesh of each fruit by removing the peel and seed is used for extracting juice with a commercial juice extractor (Xia-ping Fu, Yi-bin Ying and Hai-yan Yu, 2009). An instrument is known as refractometer which is a relatively inexpensive but important as a test equipment used to determine the soluble solids concentration (Home Brew Stuff, 2011). This instrument measures the refractive index, which shows how much light beam is “bent” when it passes through the fruit juice that depends on the amount sugar that is contained in the juice. Once the juice is in place under the daylight plate, the percentage Brix can be read by looking through the monocular (eyepiece) and the scale is read when the refractometer is held toward natural light. The refractometer readings increase when the fruit matures. The content of sugar is differed within fruit from trees with a heavy crop and light crop where with heavy crop will have lower readings while with light crop will have higher readings (Dr. Wan Zaliha Wan Sembok, 2014/15).
MATERIALS AND METHOD
Refractometer, mortar and pestle, petri dish, razor blade, knife, distilled water, and spatula (Dr. Wan Zaliha Wan Sembok, 2014/15).Fruits: orange, red and green apples, papaya, pineapple and banana.
PROCEDURE
Each group are been assigned fruits as above. The juice of assigned fruits is taken at three different parts i.e longitudinal, equatorial and traverse. The procedure of the SSC measurement as below:
A small amount of juice (2 to 3 drops) is squeezed from the fruit onto the prism
References: r. Wan Zaliha Wan Sembok, (2013/14), Postharvest Physiology Laboratory Manual (GTN3700), Laboratory Manual. Dr. Wan Zaliha Wan Sembok, (2012), Postharvest Physiology (GTN3700), Lecture Notes. Xia-ping Fu, Yi-bin Ying and Hai-yan Yu, (2009, February 10), Determination of soluble solid content and acidity of loquats based on FT-NIR spectroscopy. Retrieved from www.ncbi.nlm.govQuisQualis (2013, August 2), Climacteric and Non-climacteric Fruit List. Retrieved from www.quisqualis.com