Process Conditions Governing the Drying Rate of Tomato Powder Obtained from Foam-Mat Dried Tomato Paste
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Date
2015
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Publisher
National University of Food Technologies (NUFT), Ukraine.
Abstract
Introduction. One of the most effective ways of reducing postharvest losses in food materials is drying. However,
prolonged time of drying has the tendency of reducing the quality characteristics of highly perishable produce like tomato.
Materials and methods. Fresh tomato (“dan UTC” variety), foaming agent (egg white), foam stabilizer (Carboxyl Methyl
Cellulose), digital scale (OHAUS 3001), laboratory air-oven (model MINO50–10G039), blender (400 W, model number FPO12A). Vitamin C and protein content were determined using AOAC (2002) standard.
Results and discussion. Increase in the quantity of foaming agent (from 5 – 10 %) caused a decrease in drying rate from
20.63 g/h to 18.57 g/h, however, a further increase in foaming agent (10-15 %) caused the drying rate to increase from 18.57g/h to 20.63g/h. Increase in the percentage of foaming agent (5 % to15 %) led to a slight increase in the values of protein content (from 24.65% to 24.7889 %).Increase in the quantity of foaming agent did not cause the vitamin C content of the dried tomato powder to fall below 1.3 %, however, as the foaming agent increased, the vitamin C content showed a reduction in its values. Increase in the percentage of foam stabilizer (0.15 – 0.75 %) caused an increase in drying rate from 19.33 g/h to 20.62 g/h. The trend in drying rate was also noticed for protein content only that no significant effect in the mean values was noticed at 0.15% (24.69 %) and 0.45% (24.72 %) of foam stabilizer. For vitamin C content, all the mean values were between 1.4 % - 1.49% as the foam stabilizer increased from 0.15 to 0.75 %. Increase in whipping time (3 min to 7 min) caused a progressive increase drying rate (18.9411 g/h to 20.67 g/h) and protein content (24.71 % to 24.72%). However, the vitamin C content did not reduce below 1.4% with increase in whipping time.
Conclusions. Increase in foaming agent (egg white), foam stabilizer (carboxyl methyl cellulose) caused the drying rate and protein content of the foam-mat dried tomato powder to increase to values not below 20 g/h and 24 % respectively. However, the mean vitamin C content reduced but was not less than 1.3 %.
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Keywords
Foam-mat, Drying rate, Tomato, Paste, Powder