422. Cheese discoloration: oxidation of bixin in annatto-coloured cheeses promoted by sulphydryl compounds

Studies on application of annatto (Bixa orellena L.) dye formulations in dairy products

Annatto is often used to add color to dairy products such as butter, cheese, or puddings. In India usage of annatto is restricted to butter and cheese, however there are no tailor made formulations available to obtain standardized colour shades for the products. Hence a study was initiated to develop the appropriate annatto dye formulations and level of application in few dairy products (butter, cheese, paneer, biscuit cream, icing cream). Dye extracted from annatto seeds was used for the preparation of water soluble potassium carbonate formulation (nor-bixin, 11.24 %), oil soluble formulation (1.35 % bixin) and an oil/water soluble propylene glycol formulation (PG formulation, 1.31 % bixin). Lovibond tintometer colour units of the commercial butter, cheese and biscuit cream samples were measured for standardizing the colour concentration in the experimental products. The present study evaluates the application and stability of these formulations in butter, cheese, paneer, biscuit cream, icing cream. The products were evaluated for stability of colour and bixin during storage period. The oil/water soluble propylene glycol formulation was found to be tailor-made for all the dairy products studied though the standardized levels varied between 3.75 and 5.0 mg/kg for butter, 3.75 mg/kg for cheese, 5.0-400 mg/kg for biscuit cream, 12.25 and 25 mg/kg for paneer, 5.0-500 mg/kg for icing cream. Increasing concentration in the range of 30-500 mg/kg yielded products with light cream to orange shades, useful for decorating cakes. The average recovery of bixin from the products immediately after processing was 90-98 %. Significant changes (P ≤ 0.05) were noticed in the colour units and recovery of bixin in all the products during storage of 6 months.

Short communication: norbixin and bixin partitioning in Cheddar cheese and whey

The Cheddar cheese colorant annatto is present in whey and must be removed by bleaching. Chemical bleaching negatively affects the flavor of dried whey ingredients, which has established a need for a better understanding of the primary colorant in annatto, norbixin, along with cheese color alternatives. The objective of this study was to determine norbixin partitioning in cheese and whey from full-fat and fat-free Cheddar cheese and to determine the viability of bixin, the nonpolar form of norbixin, as an alternative Cheddar cheese colorant. Full-fat and fat-free Cheddar cheeses and wheys were manufactured from colored pasteurized milk. Three norbixin (4% wt/vol) levels (7.5, 15, and 30 mL of annatto/454 kg of milk) were used for full-fat Cheddar cheese manufacture, and 1 norbixin level was evaluated in fat-free Cheddar cheese (15 mL of annatto/454 kg of milk). For bixin incorporation, pasteurized whole milk was cooled to 55 °C, and then 60 mL of bixin/454 kg of milk (3.8% wt/vol bixin) was added and the milk homogenized (single stage, 8 MPa). Milk with no colorant and milk with norbixin at 15 mL/454 kg of milk were processed analogously as controls. No difference was found between the norbixin partition levels of full-fat and fat-free cheese and whey (cheese mean: 79%, whey: 11.2%). In contrast to norbixin recovery (9.3% in whey, 80% in cheese), 1.3% of added bixin to cheese milk was recovered in the homogenized, unseparated cheese whey, concurrent with higher recoveries of bixin in cheese (94.5%). These results indicate that fat content has no effect on norbixin binding or entrapment in Cheddar cheese and that bixin may be a viable alternative colorant to norbixin in the dairy industry.

Some volatile compounds in New Zealand Cheddar cheese and their possible significance in flavour formation: II. Volatile compounds of sulphur

The volatile sulphur compounds present in New Zealand Cheddar cheese have been studied by means of gas entrainment and steam-distillation techniques. Hydrogen sulphide was the only sulphur compound which could be detected, and after removal of this compound from the gas stream or steam distillate only a mixture of carbonyl compounds remained. Subsequent removal of these compounds completely destroyed the original cheesy aroma of the gas stream or distillate.

The parts played by hydrogen sulphide and carbonyl compounds in Cheddar cheese flavour are discussed.

The author wishes to record his gratitude to Dr H. R. Whitehead and Dr W. A. McGillivray for their helpful advice and criticism and to Mr P. L. McLaughlin for technical assistance.

Comparison of volatile compounds in water- and oil-soluble annatto (Bixa orellana L.) extracts

Annatto is a natural food colorant extracted from the seeds of the Bixa orellana L. plant. Annatto is used in Latin American cuisine to add a deep red color as well as distinctive flavor notes to fish, meat, and rice dishes. In the United States, annatto extracts are primarily used to impart orange/yellow hues to cheese and other dairy foods. The objective of this study was to identify and compare volatile compounds present in water- and oil-soluble annatto extracts. Volatile compounds were recovered using dynamic headspace-solvent desorption sampling and analyzed using GC-MS. Compounds were identified by comparison to a mass spectral database, Kovats indexes, and retention times of known standards. Of the 107 compounds detected, 56 compounds were tentatively identified and 51 were positively identified. Volatile profile differences exist between water- and oil- soluble extracts, and annatto extracts contain odorants with the potential to influence food aroma.