Dear Sekar:

Probably you can determine total solids in jams by weight difference drying the sample (here is the google books reference: http://books.google.com.mx/books?id=jQN8Kpj0UOMC&pg=PA933&lpg=PA933&dq=solids+jam+aoac&source=bl&ots=faYkXVnBCP&sig=cpvnibk_hgIuNNU6VC1upG0slPs&hl=es&sa=X&ei=zw--UMWKHuXa2wWusIGoBQ&redir_esc=y#v=onepage&q=solids%20jam%20aoac&f=false), according to the Handbook of Analsys and QC of Fruits and Vegetable products. If you need to know the soluble sugar concentracion probably you can measure total reducing sugars by some easy method (phenol-sulphuric, for example) and do the math.

I think that total sugar is less than total solids (there are acids present, too). if you have no refractometer, you should determine dry matter in vacuum oven until constant weight, which is not fast.

Though requiring a good deal of accuracy, it should be possible to determine the specific gravity of a target composition. Density of solution for a given ratio of dissolved solids will be consistant at a constant temperature. Generally the larger the sample size the lower the error. It would be worth your time to run a quick study correlating specific gravity measurements against refracitve index and developing your own conversion table.

One additional note: As you review your formula you will find all the ingredients that go into solution for the given conditions of your product/process. Keep in mind that any fruit or vegetable juice you might be adding will contain dissolved solids. Caluculating your theoretical dissolved solids prior to heat processing would be a simple excercise to start. If you have a way to measure lost moisture during processing such as steam kettles on load cells you would be able estimate with some accuracy your final % moisture/dissolved solids. Density tables for various dissolved solids are readily available on the internet or from your ingredient suppliers. Best of luck!

The high sugar content of jams and jellies can be problematic with gravimetric oven methods. Use established methods such as AOAC 920.151 for jelly and 925.45 for jams.

Drying method (AOAC) by using under vacuum oven at 70 degrees C until constant weight.

Simply, if you have an oven you can measure moisture content and (100-moisture) is total solids; if you have HPLC you measure sugar contant individually and add up them to get total sugar. Refractrometer is very cheap where you can easily measure TSS in terms of Brix. You can use polarimeter if you do have where you can still measure sugar content.

Pearson's Composition and analysis of foods which I find quite useful when combined with AOAC methods recomends that under 79/693/EEC regulations for particular countries need to be checked depending on export destinations. These regulations determin that soluble solids must be determined from the refractive index at 20*C uncorrected for insoluble solids. minimium specified refractometer soluble solids is 60%.except for reduced sugar Jam or reduced sugar marmalade which is required to be between 30 and 55%. A sucrose conversion table is also supplied and corrections for reducing sugars and citric acid are also supplied in a separate table.

When considering the fruit content of jams and jellies an insoluble solids determination is often performed which involves 20g of the product diluted to 200ml with hot water boil gently for 30min filter through a fine cloth, the residue is rediluted reboiled and filtered the resultant residue removed from the filter dried and weighed referances are made to Macara 1931 and Money and Chritian 1950 alternatively the use of a soxhlet thimble is recomended for the filtering which we have found a better and easier approach.

Non sugar solids represent the differance between total solids after drying in a vauume oven at 100*C as described by Hughes and Maunsel 1934 and total sugars expressed as invert sugar

Dear Sekar, all answers are correct. If you have an Electronic Moisture Balance like this http://www.gibertini.com/prodotti_dettaglio.php?sett=1&prod=7 you can carried out your results quickly.

Dear Mr.Sekar, measure the moisture content using Electronic moisture balance for quick results

Refractometer method analyze only total soluble solids. Normally for jams I measure total solids (soluble + insoluble) with moisture determination (thermal balance or Karl Fischer Titration): 100-moisture % = total solids. Soluble solids are not only sugars, but sugars + organic acid+ other soluble components

I can suggest the method that we use in our lab to measure dry mass for grape berries - we weigh the berries, put them on a dish which is placed in an oven at 60-70C overnight. Once dried, weigh again for dry mass. The duration of the drying will depend on the size of the sample, whether the oven has convection - so you will have to determine this by drying the sample in the oven until the sample reaches constant mass. Don't be tempted to increase the temperature too high - the sugars will caramelize.

The equivalence between sugar and total solids is dependent on the type of sample that you have - but it is generally a useful way of comparing total solids from various samples.

Freeze dryer can be used to get the total solids. Under vacuum drying will be the best.

Thanks to all. This is valuable and useful to my research work

Either by conductivity or dryness

Measure the moisture content using under vacuum oven at 70 C until constant weight.

The infrared balance easy and quick method if you are working in a factory (almost half an hour)

Dry it in a hot air oven at 105 deg C for 3 hrs and then take three weight for 15 mints once to check the constant weight. based on the validation you can reduce the 3 hrs time to required level.