Stability of yellow pigment from Lachnum sp.

Abstract:

[Objective] Stability of the yellow pigment from Lachnum sp. was evaluated. [Methods] Taking absorption value at 410 nm of the pigment as an indicator, the effect of temperature, light, pH, reducer, oxidant, metal ions and food additives on the stability of the pigment were investigated. [Results] The yellow pigment could be dissolved in water easily. The yellow pigments solution had each absorption peak in ultraviolet range and visible range and the maximum absorption wavelength were 300 nm and 410 nm, respectively. The preservation rate of the pigment was near 90% after 70 ℃ incubation for 4 h indicating that it was relatively stable to heat. Light resulted in an obvious loss of stability of the pigments. With the increasement of pH, the color of the yellow pigment became dark gradually and the A₄₁₀ of the pigments solution increased. The color of the pigments solution kept stable at pH 9.0-10.0 and the preservation rate was closed to 90% at pH 10.0 for 5 d. The yellow pigments solution was bleached by ascorbic acid and it was resistant to NaNO₂ and H₂O₂. However, it was freshed by Na₂SO₃. The color of the pigments solution was changed by Fe³⁺ and Fe²⁺, Al³⁺, Cu²⁺ and Zn²⁺ could fade the color of the yellow pigment solution, but Ca²⁺, K⁺, Mg²⁺ had a slightly effect on it. Sucrose, glucose, and potassium sorbate had no distinct effects on the stability of the pigment solution. The stability of the pigment solution was slightly influenced by NaCl solution. [Conclusion] The yellow pigment from Lachnum sp. was worthy to be developed for its good stability.