FIELD: cellulose derivatives. SUBSTANCE: method involves extraction of food squeezings first with 0.5% aqueous solution of ammonium citrate to remove pectin impurities and squeezings at ratio of squeezings to ammonium citrate solution 1: 3 and temperature 70 C for 2 h, after which extract is separated by filtration. Then, hemicelluloses are isolated from squeezings with 5% sodium hydroxide solution at ratio 1:20 and temperature 25 C while affecting mixture by shock waves from pulse electric discharges with duration 0.80 mcs and leading edge 5 ns, number of pulses in one extraction being 2,4•103, amplitude 32 kV, and interelectrode gap 0.25 mm. Extraction is performed three times, each time for 20 min. EFFECT: increased yield, degree of purity, and reduced microsemination of hemicelluloses. 9 tbl, 13 ex
