Sensory Evaluation of Ghee

The judging of ghee is probably most ambiguous because of regional preference involved in it. Consumers in different regions of the country prefer different type of flavour in ghee. In north India acidic and mild curdy ghee is preferred, in west definite curdy ghee, in south slightly to moderately cooked ghee and in eastern regions slight curdy ghee is preferred. Therefore, the ghee evaluators should consider these quality aspects and the area for which ghee is marketed. Despite this regional preference, the most desirable attributes of ghee must be remembered and judging should be done accordingly.

i. Desirable Characteristics

A good ghee sample is desired to have a pleasant, nutty and slightly cooked flavour. Ghee flavour is best described as a lack of oiliness or of blandness, sweetly rather than sharply acid. Any suggestion of rancidity is considered objectionable.

The body and texture of ghee plays an important role in its organoleptic evaluation.A good ghee sample should have well-developed granules dispersed fairly, thickly  and uniformly over the entire mass. Breakdown of granulation may result in the greasy body, which lowers the ghee score.A bright yellow colour caused by the presence of carotenoid pigments, is associated with cow ghee and constitutes a desirable criterion in areas where it is preferred.Buffalo ghee is white in colour. Sometimes, it may also have greenish tinge depending on the region and feeding schedule. Ghee from mixed milk has invariably straw yellow colour. The colour of fats always appears deeper to the eyes when melted than when in solid form.

ii. Score Card for Ghee

The main attributes and weightage given to each are shown in table .

Score Card for Ghee (BIS)

iii. Technique of Sensory Evaluation of Ghee

i) Sampling: A representative sample should be drawn from the bulk or large lot in a clean and dry glass bottle. The bottle should have a cap/lid to close.

ii) Tempering of ghee: Whenever possible, the samples should be presented at room temperature. However, the temperature of ghee can be varied depending on the method of evaluation. Many panelists feel that odour, taste and residue can be better detected when ghee is tempered to about 40oC.For texture evaluation ghee should be properly crystallized. The crystallization temperature for cow ghee ranges between 25-30oC and for buffalo ghee between 30-35oC.

iii) Rinsing medium: One per cent luke warm (40oC) saline water (NaCl) for oral rinsing the mouth in between the samples is very effective for fatty foods like ghee.

iv) Procedure: Sensory evaluation should always start with the visual observations of the ghee sample. The colour of the melted samples should be judged first, followed by observation on suspended impurities (residue). Odour is perceived immediately after removing the lid and inhaling the smell. Subsequently a spoonful of ghee is taken in mouth for taste and aroma. The body and texture should be evaluated at the end with the help of a spatula or glass rod.

iv Undesirable Attributes of Ghee

Colour defects: Two possible defects can be observed in ghee. i) too dark/ brown due to high heating temperature during ghee making and ii) bleaching, which is due to excessive oxidation of ghee during storage.

Flavour defects: The common flavour defects in ghee are: acidic, oxidized, rancid, curdy, smoky, burnt and bland or flat (lacking). The off flavours are simulated in small lots of ghee as described below for familiarizing the judges.

i) Acidic ghee: Ripen cream to lactic acidity levels of 0.5, 1.0 and 1.5% and convert directly into ghee or first convert into butter and then ghee.

ii) Curdy ghee: (a) Melt 500 g cooked butter at 80oC and leave it for 30 minutes for pre-stratification and remove about 80% of the serum. Heat remaining part upto 100oC, store at room temperature, or (b) add about 5 g of curd (dahi) into 100 g ghee and leave for 10-12 hrs at 40oC before evaluation.

iii) Smoky ghee: Put an empty glass beaker/container in inverted position on a smoke fire for sometime. Pour about 100 g normal melted ghee into the bottle. Close the bottle and turn it upside and down side three to five time.

iv) Burnt ghee: Raise the temperature of butter/ghee at last stage of ghee making to about 130oC.v) Flat/lacking defects: Either take butter oil for evaluation or prepare ghee from butter under vacuum.

vi) Rancid and oxidized ghee: Methods of developing these defects are given earlier in Unit 2.

Texture Defects: Greasy texture is a common defect in ghee and can be developed by overnight freezing (storage in refrigerator) of freshly prepared ghee followed by thawing. This practice may be repeated several times.