SOP: Composite Scoring Test

GIFSQ — Global Institute for Food Safety & Quality

Principle

Specific characteristics of a product are rated separately on a defined rating scale that is weighted so that the most important characteristics account for a large part of the total score. The scores are compounded for each panelist to arrive at a composite score. The method is helpful in grading products and in comparing quality attributes by indicating which characteristic is at fault in a poor product; it gives more information than the straight numerical method. The panelists are trained to evaluate the dimensions of the individual quality characteristics critically, and in the use of the weighted scale.

Apparatus required

• Individual judging booths (identical, uniformly illuminated), each fitted with drinking water, a glass, clean towels and a basin or receptacle for expectoration
• Coloured lighting (where needed to mask small colour differences between samples)
• Stainless steel, glass or china serving dishes and cups; plain serving trays; small stainless steel forks and spoons
• Prepared evaluation cards for the composite scoring test

Sample preparation

Prepare all samples in exactly the same manner. Code the samples with three- or five-digit numbers. Present the samples in random order (trained panel: 5–12 judges; 1–4 samples per test).

Procedure

Present the coded samples to the panelist

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Ask the panelist to rate each quality characteristic separately against its possible score, using the agreed definitions and the weighted scale

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For each sample, compound the characteristic scores of each panelist into a composite (total) score

Interpretation of results

Compare the composite scores of the samples, and compare the characteristic scores to find which quality characteristic is at fault in a poor product.

Worked specimen card from the book (orange marmalade):

• Colour — possible score 20
• Consistency — possible score 20
• Flavour — possible score 40
• Absence of defects — possible score 20
• Total score — 100

Specimen evaluation card fields: product; table of quality characteristic, possible score and sample scores; total score; comments; signature.

Precautions

• Train the panelists to evaluate the dimensions of the individual quality characteristics critically, and in the use of the weighted scale, before the test.
• Conduct judging in individual booths so that judgements are independent; allow no communication between panel members except consultation with the panel leader on any point of doubt.
• Test in the hour after a normal meal (e.g., 10.00 a.m. to 12 noon, or 3 to 5 p.m.).
• Panel members should not smoke or chew pan or supari for at least half an hour before the test.
• Judge quickly but not hurriedly; make odour observations by sniffing before tasting.
• Allow retesting, but avoid prolonged testing; tasters may swallow or spit out samples, and should rinse between samples (or use bread or puffed rice) to remove a strong flavour.
• Keep the evaluation card simple, clearly typed or printed, with unambiguous terms and directions in the desired sequence of action.

References

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