SOP: Determination of Succulence Using a Succulometer

GIFSQ — Global Institute for Food Safety & Quality

Principle

Succulence or juiciness is associated with the moisture content of the product. In the succulometer, a weighed charge of the product is pressed in a cylindrical cell under a fixed pressure for a fixed time, and the volume of juice expressed is measured; the volume of expressed juice gives an indication of the succulence or maturity. The instrument is also used to follow the residual storage life of apples (the juice yield falls sharply when surface wrinkling begins) and to judge the water-holding capacity of reconstituted dehydrated products (the more water expressed, the less juicy the reconstituted product is likely to be).

Apparatus required

• Succulometer: cylindrical cell fitted with 100 g of corn kernels; plunger 0.127 mm smaller than the inside diameter of the cylinder; hydraulic press capable of reaching 500 lb/inch²; measuring cylinder
• Shredder (for apples)

Procedure — Sweet corn

Fit the cylindrical cell with 100 g of corn kernels

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Place the plunger in the sample

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Increase the pressure gradually with the hydraulic press to 500 lb/inch²

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Hold at that pressure for 3 min

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Collect the expressed juice in a measuring cylinder and note the volume; the volume gives an indication of the succulence or maturity of the sweet corn

Procedure — Apples (residual storage life)

Peel, core and shred the apple

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Weigh 50 g of the material

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Note the yield of juice in the same way as in the case of corn

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Interpret the result: freshly harvested apples give 15–20 ml of juice, falling gradually to 10 ml in storage and then abruptly to 5 ml; the first signs of surface wrinkling appear at the time of this abrupt drop

Procedure — Reconstituted dehydrated products (water-holding capacity)

Express the water from the reconstituted product using the succulometer as above

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Note the volume expressed: a large expressed volume means the reconstituted product is unlikely to be juicy (dehydrated fruits and vegetables do not usually reconstitute to the original fresh weight, and the absorbed water may not be held firmly, giving a watery rather than juicy appearance)

Precautions

• Use the same charge weight, pressure and holding time for comparable results.

Note: in the book’s “Problems in Texture Measurement” discussion, the same succulometer test is described as “100 g of sweet corn subjected to 3,000 lb of pressure for 3 min”; the procedure above follows the 500 lb/inch² given in the instrument’s own procedure section — the two figures are an internal inconsistency of the book, flagged for the printed copy.

References

Kramer, A. & Smith, H.R., Food Packer, 28, 56 (1946).

Ranganna, S., Handbook of Analysis and Quality Control for Fruit and Vegetable Products, 2nd edition.