FOOD SCIENCE ›› 2016, Vol. 37 ›› Issue (22): 41-51.doi: 10.7506/spkx1002-6630-201622007

• Processing Technology • Previous Articles     Next Articles

Modeling and Optimization of Totally Chlorine-Free Bleaching Technique of Shellac Using Response Surface Methodology and Characterization of H2O2 Bleached Shellac

LI Kun1,2, ZHENG Hua1,2, ZHANG Wenwen1, LI Kai1, XU Juan1, ZHANG Hong1,2,*   

  1. 1. Research Institute of Resources Insects, Research Center of Engineering and Technology on Forest Resources with Characteristics, State Forestry Administration, Chinese Academy of Forestry, Kunming 650224, China;
    2. Key Laboratory of Cultivation and Utilization of Resource Insects, State Forestry Administration, Kunming 650224, China
  • Received:2016-05-23 Online:2016-11-16 Published:2017-02-22

Abstract: For the purpose of avoiding the risks arising from the application of traditional bleached shellac containing bound chlorine in the fields such as food and medicine, a totally chlorine-free (TCF) bleaching technique for shellac was developed to extend the scope of application of bleached shellac in these fields. Response surface methodology (RSM) was employed to research the influences of process parameters including ratio of shellac to bleaching solution, hydrogen peroxide (H2O2) dosage, bleaching temperature, bleaching time, stabilizer dosage on bleaching efficiency. As a result, the optimum levels of these parameters were determined as 0.08 g/mL, 2.09 mL/g (on the basis of shellac), 80 ℃, 7 h, and 3.125% (on the basis of shellac), respectively. Further, the obtained H2O2 bleached shellac was compared with NaClO bleached shellac in term of quality indicators, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) characteristics. Results showed that the molecular structure of the H2O2 bleached shellac was basically consistent with that of the NaClO bleached shellac and the alkali extracted shellac. Moreover, cold ethanol soluble substance, hot ethanol insoluble substance, thermal lifetime of the H2O2 bleached shellac were improved greatly. But the acid value was increased and the softening point was decreased significantly. The color index was 0.979 (less than 1.0) and the yield of bleached shellac was 82.03%. It was shown that TCF bleached shellac was an excellent additive and raw material for the food industry.

Key words: shellac, totally chlorine-free bleaching, process, modeling and optimization

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