Evaluation of size reduction and expansion on yield and quality of Cumin seed oil

The commonly used seed spice Cumin (Cuminum cyminum Linn.) contains 3-4% volatile oil and about 15% fixed oil. Conventional grinding of cumin is associated with problems of temperature rise, caking, clogging of sieves and deterioration of quality due to loss of volatiles. Shortcomings of the conventional size reduction were obviated by flaking and the effect of flaking on the yield and quality of volatile oil was comparatively evaluated by the scientists at Central Food Technological Research Institute(CFTRI), CSIR, Mysuru, India. For small batch size operations (200g), oil yield was found to be the same (3.4%) for both ground and flaked samples. M a n y d r a w b a c k s associated with c o n v e n t i o n a l method of grinding using hammer mill or plate mill such as mill clogging, rise in the temperature of the ground material and loss of volatile oil could be overcome by flaking. Pre-cooling of cumin seeds prior to flaking further improved the oil yield and resulted in higher retention of the flavour components (terpenic compounds). Hence, for the production of cumin seed oil by steam distillation, flaking is a promising alternate to conventional size-reduction methods. Flaking resulted in 17-18% increase in the yield of oil. Selective collection of volatile oil at different intervals of time of distillation yields fractions of different flavour profiles. It is also possible to recover oil from the condensate to an extent of 25ml in a 10kg batch distillation which amounts to 0.2% of oil on charge basis both in case of flakes and powder. The oil recovered can be added back to the oil collected by steam distillation or blended in different proportions [Sowbhagya HB, Sathyendra Rao BV and Krishnamurthy N, Evaluation of size reduction and expansion on yield and quality of cumin (Cuminum cyminum) seed oil, J Food Eng, 2008, 84(4), 595-600].