Total reducing sugars

Luff Schoorl. This method is for the determination of total reducing sugars in molasses and refined symps after hydrolysis. It is a copper-reducing method that forms the basis of some molasses purchasing contracts. 

From the data of the Fehling titration (see 2, a), the number of c.c. F of Fehling solution which would be reduced by the total reducing sugars present in 100 grams of milk is calculated by means of the formula2 ... 

Similarly the percentage r of total reducing sugars after inversion is given by ... 

The inverted solution obtained from the fruit (40 grams in 200 c.c. 50 c.c. of this inverted and made up to 100 c.c.) gave the reading + 32, so that Px = + 320 Fehling titration of the same inverted solution indicated 54 20% of total reducing sugars. 

The total reducing sugars produced from the enzymatic hydrolysis ofcellulose can be measured by the dimtrosalicylic acid (DNS) method (Miller, 1959 Andreotti, 1980), as follows ... 

Determine the total reducing sugar content in the sample by using the DNS method and prepare a curve to show the change of the reducing sugar concentration with time. 

A standard assay for both forms of enzyme consisted of mixing 108 mL of sucrose solution (120 g/L in 0.010 M acetate buffer, pH 5.5) with 12 mL of aqueous invertase solution (diluted 1 5000 [v/v]) or 12 mL of an aqueous suspension of Dowex/invertase (100 mg of powder/mL). Hydrolysis was carried out for 6 min at 37°C under agitation (lOOrpm), as previously described by Vitolo et al. (1). One soluble or immobilized invertase unit (U) was defined as the amount of total reducing sugar (TRS) (mg) formed per minute under the conditions of the test. 

E.R. Alves, M.A. Feres, E.A.G. Zagatto, J.L.F.C. Lima, Exploiting pulsed flows for heating improvement application to determination of total reducing sugars in molasses and sugar-cane juices, Curr. Anal. Chem. 5 (2009) 65. 

Reducing Sugars. Estimation of total reducing sugars (RS) as... 

TRS and Glucose Liquefied starch concentration was determined by dosing total reducing sugars (TRS), expressed in terms of glucose coneentration, after enzymatic hydrolysis of the liquefied starch present in the sample, using glucoamylase, diluted 1 200 in acetate or... 

Fig. 2 Total reducing sugar (TRS), ethanol (Et), and glucose (G) concentrations with time (7), for operation of SSF process in discontinuous runs, under two different enzyme concentration in the reactor a 2,860 U glucoamy-lase/1 reactor TRSj= 150.0 g/1 Gi=5.3 g/1 b 3,770 U gluco-amylase/1 reactor, TRS = 166.0 g/1 G =4.8 g/1. Yeast concentration ...

It is clear, however, that the operation of the SSF process in continuous reactors led to a worse performance than the one obtained in the batch experiments, with the same enzyme and yeast concentrations in the reactor and similar total reducing sugar concentration (initial, in the batch run and in the feed, for the continuous run). The concentration of free glucose in the effluent was lower than 1 g/1 for all the tested flow rates, except for the two... 

Total reducing sugar concentration (TRS) and glucose concentration (G), in the outlet of reactors 1, 2, and 3, for different feed flow rates (ftccd)-T Assay time... 

Fig. 3 SSF continuous run 1. Ethanol (Et), total reducing sugar (TRS), and glucose (G) concentrations with residence time (6).

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