Determination Of Fruit Firmness
Introduction
The development of sensors to measure fruit internal quality variable is one of the challenges of post – harvest technology. Several variables can currently be measured, including sugar content, firmness and internal disorders.
Fruit quality is related to both internal variables (firmness, sugar content, acid content and internal effect) and external variables (shape, size, external defects and damage). Increasing consumer demand for high quality has led to the development of optical, acoustic, and mechanical sensors that determines this quality.
Fruit firmness is one of the most important quality variables; it is an indirect measurement of ripeness and its accurate assessment allows appropriate storage periods and optimum transport conditions to be established. Fruits firmness can be estimated by different techniques. There are two types of methods that can be used to determine fruit firmness i.e penetrometer and TAPlus Texture Analyser.
The penetrometers are available with dial gauges calibrated in both metric (kg) and imperial (lbs) measurement and can be obtained to cover different ranges of pressure suitable for measuring either soft or harder types of fruit, depending on the variety and the stage of ripeness of the fruit to be tested.
There are three detachable plungers available: 1. One of 8 mm (½ cm²) diameter generally suitable for use in testing softer fruit (e.g peaches, nectarines, plums). 2. One of 11 mm (1 cm²) diameter generally suitable for use in testing harder fruit (e.g apples, pears) 3. A pointed plunger for use in testing avocados.
Ideally the penetrometer should be bench – mounted on a fixed, rigid drill stand to ensure that pressure is applied at a steady controlled rate and at a constant angle to the fruit i.e vertically downwards. This is more difficult to achieve when using a hand – held penetrometer.
While, Stable Macro System, TA.XTplus texture analyzer measures texture