Annual Report 1961 - BEEP

- JOwas taken to measure, with the help of arecording wattmeter, the power consum ptionof each mill under operating conditions duringperiods of 24 hours or more,The power consumption of each mill whenrunning free was also measured, Finally, onthe last day of the crop, the tail bars wereremoved and the power consumptions of theprime movers and gearings of three mills wererecorded.It was unfortunately not possible duringthis crop to vary operating conditions suchas hydraulic load, mill speeds, settings, etc. andto study the influence of these factors onpower consumption, but it is intended to takefurther measurements during the 1962 cropwith a view to interpreting the results morefully.(h) Filterability of raw sugar. A numberof average raw sugar samples from most factoriesof the island were analysed for starch,silica, gums, wax and phosphates with a viewto determining the cause of the poor filterabilityof some of the raws produced. Thefilterability values were determined by the Nicholsonand Horsley method.It seems that, under Mauritius conditions,starch is the main cause of poor filterabilityof certain consignments of raws. The deteriorationobserved in this connection during thepast few years appears to coincide with theextension of new cane varieties containing morestarch.A comparison was also made between theElliot, and the Nicholson and Horsley methods forthe determination of filterability. The resultsobtained indicate that the latter method ismore reliable and should be adopted if abetter assessment of the refining qualities ofMauritius raws is to be achieved.(i) Study of the rnieroflora of raw sugars.In a report issued in 1959 *, it was shown thatheavy financial losses arc incurred annually onthe raws exported from Mauritius. Theselosses were attributed mainly to the action ofmicro-organisms on raws of poor keepingquality.in 1960 a note was received by the MauritiusSugar Syndicate from Messrs. Tate & Lyle Co. Ltd.conccrnmg the deterioration, by highly ferrncnt.uiveosmophilic ycasts, of a parcel of4,300 tons of Mauritius raws which had beenstored in a large silo and reclaimed severalmonths later. It was stated that two distincttypes of yeasts had been isolated from thesugar and tested. One was of the normalosmophilic tyre and contained no invertase. butthe second was highly fermentative and containedinvertase. This second species of yeastwas present in considerable number and hadnot been encountered before in raw sugar.It was therefore decided to take up thequestion during the 1961 crop in order toascertain whether osmophilic ycasts arc normallyfound in Mauritius raws and, if so, in whatnumbers. Earlier in the year it was arrangedthat, while on leave in Europe, Mr. Antoine,Pathologist, and Mr. de Frobcrville, Assistant SugarTechnologist, should obtain as much informationas possible on this question. The problemwas discussed with Dr. Scarr of Tatc & LyleResearch Laboratories while Mr. Antoine visitedthe Ccntraalburcau voor Schimmeleultures atDelft in Holland. The valuable assistancereceived from these organizations is gratefullyacknov ledged.A preliminary screening of sugars from the23 factories started in October, followed byfermentative tests and plate counts on osmophilicagar. Of the yeasts encountered in someof the sugar samples. Saccharomyces rouxii wasthe commonest, but six other species were alsoidentified. Ycast content of massecuites asdischarged from the vacuum pans. of the massecuitefed into centrifugals after cooling, ofsugar and molasses, was determined in severalfactories. It appears at this stage that contaminationby osmophilic yeasts takes place inthe crystallizers, Recommendations on suitableprecautions will be made as soon as the resultsof investigations now in progress become available.Advisory Work. Several studies were carriedout and a number of recommendations made.. Weight and polarization changes of raw sugars exported to the U.K. Technical Circular No. 12, M.S.1. R.1.mimeo, 20 p.