DR RICHARD VOLZ (Plant & Food Research)
The soluble solids concentration is a defacto measurement for the sugar concentration in the juice of the fruit. And the sugar concentration is a measurement of the sweetness of the fruit. It’s important in terms of how the consumer perceives the taste of that fruit. For soluble solids concentration we use a refractometer. A refractometer essentially measures the refract index of the light and the bending of that light is proportional to the density of the solution and in apple juice the main solute in the juice is soluble solids, which is mostly made up of sugars. So essentially what we do is as soon as the penotrometer has moved up out of the fruit, there is usually a drop of juice and the drop of juice can go onto the refractometer, a button is pushed and a soluble solids reading comes up.