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• Nguyen Thi Thanh Huong, Nguyen Cong Khan , Ha Thi Anh Dao

  Received: 28-05-2012 / Accepted: 04-06-2012

   Abstract PDF (VIETNAMESE)

  The popular use of additives in food may adversely affect community health. This study aimed at improving management of the use of additives in food processing in Quang Binh province. The intervention model front-end evaluation was conducted from April 2009 to December 2011. The interventions included training, direct communication with leaflets and propaganda on TV, increased inspection, testing, point of use modeling, free supply of and consultancy on use of food additives. The samples were taken from 164 of food processing and business units for the welding tests, coloring, acid benzoic and sorbic acid both before and after intervention. It was found that after intervention, the sample rate of foof with toxic color additive dropped from 25.8% to 9.9% and borax food samples decreased from 37.1% to 19,7%. The proportion of unsatisfactory food samples decreased from 46.3% to 8.1% for benzoic acid and from 50.0% to 18% for sorbic acid.

• Study on Extraction and Separation of Anthocyanin from Hibiscus Sabdariffa Calyx. Application to Produce the Rapid Indicator Paper of Detecting the Borax in Food

  Nguyen Thi Hien, Nguyen Thi Thanh Thuy, Nguyen Thi Loan

  Received: 29-05-2012 / Accepted: 12-08-2012

   Abstract PDF (VIETNAMESE)

  The extraction and purification of anthocyanin pigments from calyx of Hibiscus sabdariffa, and its use as potential rapid indicator paper for detecting the borax in food were investigated. By using the colour comparison and the differential pH methods, the optimal conditions for pigment extraction were identified as follows: ethanol solvent to water is 50:50 with supplement 1% HCl; the ratio of solvent per raw-material is 14 ml/1g; extracting duration is 6 days. By fractional extraction method, the crude anthocyanin pigments are isolated from extracts of Hibiscus calyx. The concentration of pigments in the dry and fresh material was 15.2% and 1.06%, respectively. The acidity of the dry ingredients is 3.37 mldH+ /1g of raw material, the acidity of the dry pigment is 3.83 mldH+/1g of colour substance, respectively 0.58 mldH+ /1g dry material and the acid reduced 83%. By surveying several conditions for production of the indicator paper, the appropriate parameters are selected with color dilution of 1gram of dry colour substance to 400ml distilled water ratio; duration of color impregnated on paper is 120 seconds; the duration of indicator paper exposure to food (or food fluid) is 90 seconds. A minimum level of the indicator paper for detecting the borax is identified as 40 mg/1 kg of food. This result has shown that the minimum detectable limit is equivalent to turmeric paper. As for sensitivity, when testing on a number of food materials, the similar results were also been obtained.