Loss of Dyes by HPLC Analysis in Ras Cheese and its Whey

Abstract

In a previous study, the extract of Turmeric and β-Carotene was extracted from local cheap products for coloring the Egyptian Ras cheese instead of the imported Annatto dye. Ras cheese was made with this extract, and compared with control cheese. HPLC technology was used to estimate the stability of the added dye during making of cheese when fresh) and during storage period (180 days), and compared with control samples. HPLC analyzed was performed to detect and follow the reduction of the colour of cheese, and the loss of dyes in the whey. Results showed that after extraction for HPLC analysis of the annatto extract (norbixin) used in making Ras cheese, the recovery of norbixin from fresh Ras cheese averaged 80.57%, while the norbixin content in the whey of Ras cheese was 19.35%. HPLC determination of β-Carotene in Ras cheese was about 4.28% from a total amount of β-Carotene being used in cheese making process is lost in whey. Recovery of β-carotene from fresh Ras cheese was 95.32%. Recovery of β-carotene from uncolored Ras cheese fresh Ras cheese and whey sample were (96.00%/3.50%), respectively. The results from HPLC determination of β-Carotene in ripened Ras cheese after six month old cheese were 37.23%. Residual Annatto was extracted from ripened Ras cheese after 180 days from storage which was 34.07%. While, residual curcumin percentage in Ras cheese after ripening time was 43.20%. Annatto is less stable compared to Curcumin and β-carotene extracts under the same condition. When used Curcumin and β-carotene extracts, they forming a stable colour little of which is lost during separation of the whey. The economic feasibility between the price of colorant added and loss of some of it in whey, it is clear that annatto is less expensive but will be larger loss of whey. In contrast, in the case of Curcumin and carotene extracts, a little amount of the added extract is lost in the whey. On the other hand, it is recommended that the waxing of Ras cheese wheels to preserve the colour of oxidative degradation.