Several studies reported the use of NIR spectroscopy for the determination of reducing sugars not only in must but also in wine. NIR analysis for sure could be a rapid and simple method of determination but, of course, you should build up you own model before perform the analysis. In literature you could find several papers on this topic.

There are simple IR spectrometers available

https://www.researchgate.net/publication/42440268_Rapid_and_mobile_determination_of_alcoholic_strength_in_wine_beer_and_spirits_using_a_flow-through_infrared_sensor

Article Rapid and mobile determination of alcoholic strength in wine...

Yes you can determine the total carbohydrate from your sample just following the method of modified anthron  the paper is published in Indian Journal of applied research entitled "Estimation of glycemic carbohydrates from commonly consumed foods using modified anthrone method" without treating with enzyme simply do the assay will give you total carbohydrate.

Dear Li,

In our laboratory we work with a simple analysis called Somoghy-Nelson for determination of total sugars. To determine the glucose we use an enzymatic method GOD and difference of the total know the fructose content (for grape wine).

Hi Ruiqi,

I used to determine glucose+fructose during must fermentation with a simple enzymatic kit based on a colorimetric method. Here below you have one of them, although I used to work with Boehringer's

https://secure.megazyme.com/D-Fructose-D-Glucose-Assay-Kit

Such methods are quite easy and straightforward and you can test more than 20 samples at the same time.

Regards

If the wine is alcoholic, first distil and recover the alcohol at 78.5oC in a known volume of the wine and replace the volume of alcohol recovered with equal volume of distilled water in the wine distilled. This is to give real and not apparent values of measurements that will follow because alcohol is lighter than water. Thereafter, bmeasure the density of the wine sample so prepared (mass/known volume) with a densitometer from where the mass of the known volume of wine is generated. Alternatively, measure the mass of the known volume of wine with a mass balance. The % sugar (brix value) measured with g a refractometer is equal to ((mass of sugar/mass of wine) multiplied by 100). Then the mass of sugar is then generated by (mass of the known volume of wine multiplied by % brix value of the known volume of wine) divided by 100.

However, if the wine does not contain alcohol, the initial distillation is not necessary.

there are three methods can be used to determine total carbohydrates

1. By difference (determine all other components like protein, fat, moisture and ash sum the value and subtract from 100 ml the difference value is the total carbohydrate.

2. Use phenol sulfuric acid method or

3. Using the modified methods of anthron method