. Journal. solutiort^ in which a precipitate isproduced, as in the purification of the solutionsobtained from the diastase conversions, it iscarried down with thLs and is thus lost to * Use of iaka-diaatasc in culiinaling starch. In a series of experiments in which 2 grms. ofanliydrous starch was gelatinised in 200 ofwater and, after cooling, subjected to the actionof 01 grni. of taka-diastase dm-ing diflferent periodsat 38% it was found that so long as the time ofconversion exceetls (5 hours, maltose and dextroseare the only products formed ; up to the sixthhour some dextri
. Journal. solutiort^ in which a precipitate isproduced, as in the purification of the solutionsobtained from the diastase conversions, it iscarried down with thLs and is thus lost to * Use of iaka-diaatasc in culiinaling starch. In a series of experiments in which 2 grms. ofanliydrous starch was gelatinised in 200 ofwater and, after cooling, subjected to the actionof 01 grni. of taka-diastase dm-ing diflferent periodsat 38% it was found that so long as the time ofconversion exceetls (5 hours, maltose and dextroseare the only products formed ; up to the sixthhour some dextrin is present, which interfereswith the calcidatious, but when the conversionis prolonged to say 12 or 24 houre, the whole of thestarch is found in the solution as maltose anddextrose and can be accuiately estimated. Thecurve given in Fig. 1 shows that the dextrosearises solely from pre-formed maltose ; as timegoes on, the dextrose increases wliiLsfc the maltoseproportionately falls. The ciu-ves of dextrose. II Fio. I. and maltose (calcidated as starch) are strictlycomplementary. In this action, the starch isfirst converted into maltose ))y the ordinaryiliastatic enzymes, and this sugar is then trans-formed into dextrose by the maltase, which is thespecial feature of the taka-diastase. The maltasecomes into action comparatively .slowly, so thatafter 6 hours only one-tenth of the original starchw present as dextrose. Subsequently, however,the rate at which dextrose Ls formed increases,following very nearly a straight line curve between6 hours and 28 hours, wlien about 00°;, of is present as dextrose ; the rate of formation ** Wben basic lead acetate is added to the solution obtainedhy the diastase conversion of purified starch not the slightestiirecipitate is pritluoed with the dextrin existinR in solution :hut results obtained in a series of special experiments showedthat If sodium tarlKinate is subsequently added, or hydroKensulphide is passed so as to precipitate t
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
