The effect of drying process on the pigment content and composition of table beet varieties

The food industry requires natural colouring agents in increasing quantities. Beet root is highly adapted to this purpose with its red(betacyanin) and yellow (betaxanthin) pigments suitable for numerous products. The two pigments are, however, very heat-sensitivedepending not only on the method of drying as well.In our experiment we tested 6 table beet varieties with vacuum drying (instrument: Eurovac KIT-150) and obtained very big differencesin the suitability of varieties for drying. The less colour loss was measured in Bordó (16.84%), while Rubin and Cylindra indicated 45.15 and47.18% loss respectively.During the drying raw material with higher colour content produced higher rate of pigment loss (r = 0.880). In our experiment we foundadverse effects on colour material and dry matter content in the fresh beet root. The variety with higher solids (mainly sugar) resulted in higherpigment loss (r = -0.847) during the vacuum drying process. Furthermore, we stated that the yellow pigments (betaxanthin) were less heatsensitive during drying than the red (betacyanin) ones.For the production of beet root powder varieties of high pigment content but low water soluble solids content (sugar) are needed