FLAVOUR AND AROMA OF GHEE

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1. Flavor and Aroma of Ghee Presented by M.Dharani M.Tech Dairy chemistry(MTM19002) CFDT,TANUVAS,Chennai-57 . [email protected]

2. Flavor and Aroma of Ghee Effect of Heat on Flavor of Ghee The flavor of ghee is due to a complex mixture of compounds produced during the various stages of processing. The heating process generates flavor compounds through the interaction of protein degradation products, lactose and minerals, and possibly through the degradation of FFA and lactose. Heating process positively improve the ghee flavor, but also seems to drive off putrefactive odors which may have developed in the butter.

3. FLAVOR COMPONENTS OF GHEE Carbonly Mono , di - carbonyls and methyl ketones 01 Alcohol 1-Hexanol, ethyl, nonanol ,Ethanol, n- butanol 04 Lactones Delta,gamma and n- saturated aliphatic lactones 02 Diols 1,3-butanediol propanediol 05 Free fatty acids and their esters Ethyl esters of C3, C5, C6, C8, C14, C16, C18 and C18:1 fatty acids propyl ester of C4 fatty acid 03 Hydrocarbon saturated and unsaturated (C9—C20) cyclopentane , ketohydrocarbons (C3—C9) 06

4. Carbonyls Acetone, butanone, formaldehyde, acetaldehyde Naturally occurring in milk. Methyl ketones Hydrolysis of b- ketoglycerides to b- ketoacids followed by decarboxylation during heat processing Conversion of b- ketoacids to beta- ketoacid - glycerides (which also occur in fresh milk) by the action of heat and water or by the action of lipases. Auto Oxidation of unsaturated fatty acids to b- ketoacids followed by decarboxylation S iginificance Dehydration and thermal degradation of carbohydrates -formation of polar ( dicarbonyl ) compounds i.e., diacetyl, furfural and hydroxymethylfurfural . Alkan-2-ones -major class of monocarbonyls . Propanone and pentanone - most abundant in cow and buffalo ghee. clarification of butter into ghee -increase in the proportion of alkan-2-ones with a decrease in the proportion of aldehydes . Desi ghee made from buffalo milk contained significantly higher concentrations of carbonyl compounds and had a better flavour than ghee made under controlled conditions. FFA and carbonyls are transferred from the aqueous to the fat phase during heat clarification as a result of moisture removal.

5. Lactones coconut-like aroma . Delta-lactones –predominant Lactones proportional to temperature of clarification . Lactone level in ghee was about twice that of butter. Hydrolysis during heat processing of lactogenic glycerides to hydroxy acids followed by ring closure or by lipolysis of glycerides before ring closure. d-lactones; d- octalactone (C8), d- decalactone (C10) and d- dodecalctone (C12) - influencing the flavour of ghee. At 0.2 ppm it imparts sweet creaminess , tending towards fresh coconut flavour at higher levels. The flavour threshold of d- decalactone is 10 times that of d- octalactone and has higher threshold than other two. The higher straight chain lactones do not contribute significantly to the flavour of butterfat. delta- and gamma-lactones in buffalo butter and ghee were less than those in cow butter and ghee. Lactone potential of milk fat is affected by feed and seasonal variation.

6. FFA and Esters FFA are undesirable because the shorter-chain FFA responsible for the rancid flavour&catalyze the fat oxidation reaction. Various FFA including C 6,C 8,C 10,C 12,C 14:1,C 15,C 16,C 18 and C18:2 were reported to occur in ghee. C6—C10 FFA account for only about 5—10% of the total FFA in ghee-unique flavor. Buffalo ghee appears to lack the FFA C 6,C 10 and C 15 while cow ghee exhibited a unique presence of C 18:2. The short-chain FFA, C2 to C4, have not been identified in cow or buffalo ghee ,lost due to volatilization during the heat clarification of butter. Esters: These powerful odour compounds may be important in the flavour of ghee . Esters may originate from the esterification of short chain alcohols and FFA by the action of bacterial esterases in LAB.

7. Miscellaneous substances Decomposition products include acrolein , dimethyl sulphide , alcohols, diols and denatured protein compounds. Indole and skatole (3-methylindole) which contribute to the desirable flavor of butter could also pass over into ghee, in their original or modified form. Decomposition of milk constituents like fat, proteins, amino acids, lactose and glucose during the clarification process have been reported to play a possible role in the flavor of ghee

8. Source of flavor compounds of ghee use of ripened milk, cream or butter A mixed culture of l.lactis C-10, l.diacetylactis DRC-1, S. thermophilus and l.bulgaricus for ripening cream for ghee making. They found DRC-1 and C-10 strains to be the most suitable cultures. 3% of the DRC-1 culture and incubation at 30°C for 18 h followed by clarification at 115°C for 5 min-resultant ghee was comparable to that of desi ghee. Free fatty acids and carbonyls, of ghee were higher in ripened cream ghee than in fresh cream ghee. S ynthetic mixture 3 ppm of d-C10 lactone , 15 ppm of d-C12 lactone , 5 ppm of decanoic acid and 10 ppm of nonanone-2. flavor in butteroil was comparable to that of cream butter (CB) ghee. Steam Volatile Monocarbonyls (SVMC) More intimately associated with the fat phase. The SVMC partitioned with butter during churning(67%) more than with the milk serum. About half of the SVMC in butter were lost during the clarification of the butter to ghee, probably due to volatilization.Only 57% in ghee. Inversely proportional to acidity of cream.

9. Mohammed L. Sserunjogiab *, Roger K. Abrahamsena and Judith Narvhusa :A Review Paper: Current Knowledge of Ghee and Related Products(1998) Abou-Donia,S.A . andEl-Agamy,S.I . (1993) Ghee.InEncyclopaedia of Food Science, Food ¹echnology and Nutrition, Vol. 6, eds R. Macrae , R. K. Robinson and M. J. Sadler. Academic Press Ltd, London, pp. 3992—3994. Borgstrom , S. and Jonsson , H. (1986) The composition of the free fatty acid fraction in milk, cream and butter. XXII International Dairy Congress, the Hague, September 29— October 3. Reidel , Dordrecht, Holland, pp. 43—44. REFERENCES

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