Texture can be a measure of firmness and finished product quality of fruits and vegetables as affected by cultivar growing conditions, maturity, handling processing variables, etc. For certain tomato products, the firmness of tomato dices or pieces is also an indication of wholeness and for integrity which is an important quality factor. FTC Systems are used by most all major processors of tomato products, to measure these quality factors in raw and canned tomato dices.
Equipment
FTC TMS-Pro System used with Model CS-1 Standard Shear Compression Test Cell and a 2500N Load Cell. Rate of Shear is set for a 30 seconds full stroke of ram with the program set to calculate the peak force incurred during the downward motion of the instrument.
Sample Preparation
1. Place a sample large enough for 5 replicated determinations on a 3/8 inch mesh screen.
2. Allow to drain for about 2 minutes or until excessive dripping stops. Samples canned in juice could also be rinsed with room temperature water prior to draining.
3. Remove any core, stems and other extraneous material.
Test Product
1. Carefully weigh a 200 grams representative sample and place in test cell box.
2. Place lid on the cell and slide into cell guide of the system.
3. Start the ram in downward motion.
4. Record the force required to compress and shear the sample, which is a measure of firmness.
5. Remove the cell box and wash by immersing in water or by spraying with water after each text. Wash the blade portion of test cell at intervals frequently enough to prevent drying.
Data
The results of 5 replications on 5 unknown canned samples of dices (#10 can size).
Pounds force required to Compress and Shear a 200 gram sample in Model CS-1 Standard Shear Compression Test Cell at a 30-second/stroke Shear Rate.
Replication Sample Number
1 2 3 4 5
1 240 132 177 174 168
2 225 126 180 183 180
3 234 114 201 180 192
4 240 132 201 189 201
5 258 126 174 168 192
AVERAGE 239.4 126.0 186.6 178.8 186.6
Conclusion
The FTC TMS-Pro System detected significant differences among the five samples of canned diced tomatoes submitted, with a high degree of precision for a product of this nature. Sample 1 was the firmest, (average 239.4) sample 2 the softest (average 126), and the other 3 samples ranged in between.
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