How to measure and analyse the texture of food, cosmetics, pharmaceuticals and adhesives.

Tuesday, 18 December 2018

Fruit Texture: How to measure detachment and deseeding force

Farmer picking grapes

Measuring Detachment Force

Table grapes are highly perishable, non-climacteric fruits. Their shelf life is shortened by loss of firmness, berry drop, discoloration of the stem, desiccation and fungal rots.

The berry drop is due basically to dry-drop (or abscission) – ethylene in conjunction with falling auxin levels, induces the formation of an abscission zone at the pedicel-berry junction, thus stimulating their drop. Grape varieties susceptible to berry drop present a huge problem for successful storage and marketing. For this reason it is required to predict and control the harvested abscission of grape berries, which is not only of inherent scientific interest, but it also has considerable commercial significance.

The fruit detachment force, an index of berry adherence strength which controls berry drop, consists of the linking force (between berry brush and berry flesh) and tensile strength of the abscission zone. Researchers have found there to be a high negative correlation between fruit detachment force and harvested berry abscission. Therefore, the progress of abscission can be determined by the changes in fruit detachment force. A quantitative prediction of berry drop and optimisation of storage conditions for grapes would therefore be of high value.

To measure detachment force, an individual grape stem is put through a hole of a plate and firmly clamped with a spring clamp. The spring clamp is then fastened to the load cell fixture. The texture analyser moves upwards until they are pulled apart. The maximum force encountered during this tensile test is termed the fruit detachment force.

Measuring Deseeding Force

Researchers have also documented a method for the measurement of deseeding force of papaya.

Deseeding force is measured by cutting the fruit into halves horizontally at the top and bottom of the half, leaving approximately 4cm section at the equator, which is placed on a plate with a hollow centre. A triangle blade-like tool (i.e. Fracture Wedges) is used to remove the seeds and the force required to push the fruit placenta and seeds out from the top to the bottom of the section determined.

Watch the video below
to see a summary of the types of testing possibilities that are available for the measurement of fruit and vegetable texture to provide quality control tools and ultimately, consumer satisfaction:

View fruit and vegetable video

For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

TA.XTplus texture analyser with bloom jar The
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