Determination of soluble solids concentration
To determine soluble solid concentration in some fruits including tropical and temperate fruits by using handheld refractometer. Introduction
“Sugar are the major soluble in fruits juices and estimate of sweetness. Other soluble materials include organic and amino acids, soluble pectins, and others. Soluble solid concentration can be determined in a small sample of fruits juice using a hand held refractometer. The measurement must be made at 20°C to get an accurate value. This instrument measures the refractive index, which indicates how much a light beam is "bent" when it passes through the fruit juice”. (D. Gamer and etc, n.d)
Soluble solid concentration (SSC) or also known as total soluble solid (TSS) content of a solution is determined by the index of refraction. This is measured using a refractometer, and is referred to as the degrees Brix. Brix is the term used when a refractometer equipped with a scale,based on the relationship between refractive indices at 20°C and the percentage by mass of total soluble solids of a pure aqueous sucrose solution. This tests the solids concentration of a sucrose containing solution. It is widely used during fruit and vegetable processing to determine the concentration of sugar in the products. Sugar concentration is expressed in degrees Brix. At 20°C, the Brix is usually consider equivalent to the percentage of sucrose (sugar) in the solution (60° Brix is equivalent to a sugar content of 60%).
As fruits matures, refractormeter readings will increase, indicating fruits maturity is progressing. The fruits from heavy crop will have lover reading than fruits with a light crop under similar growing condition. The reducing in moisture availability, high temperature, and high sun light will increase the sugar content. As with firmness, refractometer reading will different vary by fruits position. Fruits in exposed area, have higher soluble solid and vice versa from the fruits heavily shaded where have the