Maturity Indicators for European Pears
There are various indicators that can be used to determine pear maturity. Using a combination of methods usually can give the most accurate results.
The two most commonly used indicators in the Australian industry are flesh firmness and total soluble solids (TSS) and standards have been developed to guide growers for 'Williams', 'Buerre Bosc' and 'Packham's.' Starch content can also be used to determine maturity but is less common in the industry.
Flesh Firmness
Flesh firmness is often considered the most reliable measure of maturity. As fruit matures, flesh firmness drops. Flesh firmness is measured through testing the pressure of the pears using a penetrometer with an 8mm plunger.
Figure 1: Penetrometer with an 8mm head, used to test flesh firmness
Total Soluble Solids (TSS)
The juice of pears contains compounds such as sugars, other carbohydrates, acids, salts and amino acids. These are referred to as the total soluble solids. As pears mature the sugars become the main component of the total soluble solids and their concentration can be estimated using a refractometer (Little and Holmes 2000). TSS is measured as oBrix
TSS is not considered as reliable an indicator as flesh firmness. It is however a good measure of eating quality.
Figure 2: Hand held Refractometer used to test TSS
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