Volume 9

Seventh International Congress of Applied Chemistry : London, May 27th to June 2nd, 1909.

  • International Congress of Applied Chemistry
Date:
1910
Catalogue details

Licence: In copyright

Credit: Seventh International Congress of Applied Chemistry : London, May 27th to June 2nd, 1909. Source: Wellcome Collection.

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    wbicli I knew to contain immature starck granules I contrived to raise tke value in tke case of rye by about 9° or 10°C. In thè case of tapioca starcb, whick, by reason of its modo of prepara tion for tke market, might bc ©xpected to yary considerably, I found great divergencies from tke gelatinisation temperature usually given, one sample from Penang golatinising at 68‘5°C., another from Java as low as 53'0°C. In considering tk© variations, tke state of maturity, except in quite abnormal cases, is tke governing f'actor, and tk© small imma- ture granules, wbicb presumably kav© a relativoly tkick cuticle of cellulose, are not so easily attacked by keat, minerai acids nor diastase, as tkose of greater maturity. Tkis fact strengtkens tke vicw keld by Nageli many years ago, tkat tke layers form internally in tke starck granule during growtk, tke older ones expanding to make room for tkose newlv formed, consequently tke outer layers bcing tke tbinnost would be more easily penetrated by attaeking auents. o I bave refrained from including tables cataloguing my results, as 1 bave extended my observations to otber starcbes and I bop© to publisb sbortly a later communication in wbicb tb©se fìgures Avill 1«> found. Finally, my best tlianks are due to Mr. Jokn Carr, of Messrs. Peek, Frean and Co., for supplying me witb samples and for grantiug me facilities for carrying out tkis work. Discussion. Mr. E. J. Watkins said tke autkor’s metkod of estimating tke quantity of insoluble proteins or glutea in flour bv purely micro- scopie raethods is an interesting one, though it seems doubtful wketber otker workers eould obtain similar agreement between tke optical metkod and tke ordinarv wash-out process. Tk© weak point seems to be tkat even if it were possible to lav down conditions whick would enable anv one to estimate tk© insoluble proteins with fair approack to accuracy, it would stili be quite impossibl© to obtain any idea of tke quality of tke glutea bv tkis metkod, and resort would bave to be made to tbe ordinary processes for information.
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