Odabrane analize hitozana iz dijetetskog suplementa na tržištu – razvoj modifikovanih metoda za određivanje stepena deacetilovanja / Selected analyses of chitosan from dietary supplement on market – development of modified methods for degree of deacetylat

Introduction Chitosan is an unbranched binary heteropolysaccaride obtained from chitin by partial alkaline deacetylation. Chitosan is biocompatible and biodegradable polymer used in pharmacy and biomedical investigations. In dietary supplements chitosan is used for weight loss and cholesterol-lowering properties. Aim The aims of chitosan’s analyses of capsules were to determine: the weight variation tests for chitosan in 0.15 g chitosan/capsule, chitosan characteristics – degree of deacetylation DDA(%) via comparison of proposed modifications of FTIR-ATR spectroscopy and acid-base titration; moisture and ash content and functional characteristics – water binding capacity (WBC) as well as fat binding capacity (FBC). Method Tests were performed for dietary supplement on market TIENS (0.15 and 0.25 g pure chitosan/capsule). For DDA(%) FTIR spectra were recorded on Nicolet iS10 Thermo-Scientific USA (ATR technique) and for acid-base titrationretitration technique with indicator bromphenol blue was applied. Loss on drying determined at 105˚C and 60˚C (2 h) and ash at 650˚C (4 h). For WBC (10.00 ml of redestilled water) and FBC (10.00 ml soybean, corn or sunflower oil) were placed in cuvetes (30 ml) and centrifuged 3,500 rpm (25 min). The weight variation tests for 0.15 g chitosan/capsule from 2 series each of 20 weights gave x=0.1498±0.0063 g (99.87% of declared mass). Applying FTIRATR spectroscopy (two equations with absorbance ratio of bands A1655/A3450 and A1320/A1420 with corresponding baselines) provided the most harmonized DDA(%) of 92.66% (baseline b for peak at 1650 cm-1) and 89.40% (baseline b6(A1320) and b9(A1420) in relation with acid-base titration 91.49%. Moisture content was x1=7.55% (105°C) and x2=7.03% (60°C) (acceptable values <10%) and ash content of 0.51% is in accordance with regulation for usage in food industry. Higher value of WBC (496.8%) in comparison to FBC (in range 332.4- 352.8%) was obtained. Conclusion The characteristics of chitosan: high DDA(%), low moisture and ash contents and functional characteristics indicate the high-quality of chitin (red leg crab – declared by manufacturer) for supplement. The results obtained by proposed modifications for DDA(%) determination were in good accordance.