Tomato concentrates

Comparison of in-line consistency measurement of tomato concentrates using ultrasonics and capillary methods),/. Food Proc. Eng. 25, 571. 

Marsh, G.L., Buhlert, J.E., and Leonard, S.J., 1980. Effect of composition upon Bostwick consistency of tomato concentrates. J. Food Sci. 45 703-706. 

Enough condensate was processed to give several grams of volatile tomato concentrate. The volatiles obtained from this extraction... 

Because of the compressible nature of food dispersions, the direct determination of the magnitude of centrifugal force employed in the separation of the phases. Therefore, rheological properties of plant food dispersions, such tomato concentrates and concentrated orange juice, are based on the mass of pulp. In starch dispersions, they are based on the mass fraction of starch granules, denoted as cQ, as described in Chapter 4. 

Tomato concentrates and concentrated milk samples are examples of foods in this category. Alternatively, the combined effects of temperature and concentration on the power law consistency index, K, are described by ... 

Rao, M. A. and Cooley, H. J. 1983. Applicability of flow models with yield for tomato concentrates. 

Yoo, B. and Rao, M. A. 1996. Creep and dynamic rheological behavior of tomato concentrates effect of concentration and finisher screen size. J. Texture Stud. 27 451-459. 

Figure 3-22 Flow Behavior (power law) Data on Tomato Concentrates at 76-120°C (From Rao et al. 1999).

Deviation from Cox-Merz rule appears to be an indication of structural heterogeneity in a food. For example, significant deviations from Cox-Merz rule were found in dispersed systems, such as tomato concentrates (Rao and Cooley, 1992) and cross-linked waxy maize starch dispersions (da Silva et al., 1997 Tattiyakul and Rao, 2000). In contrast to the observation on several foods of dispersed nature, the Cox-Merz rule was found to be applicable to fluids with homogeneous structure, such as dispersions of guar gum (Mills and Kokini, 1984) and locust bean gum (Lopes da Silva et al., 1993). 

Nevertheless, in order to understand the role of various components of PF dispersions, systematic studies on the role of the amount and size of insoluble solids can be conducted by careful preparation of the test samples. Figure 5-2 illustrates the processing steps used to vaiy pulp particle size distribution in tomato concentrates (Tanglertpaibul and Rao, 1987a). Similar processing technique was used in the preparation of apple sauce samples by Rao et al. (1986) and Qiu and Rao (1988). The amount and the size distribution of the insoluble solids in the PF dispersions... 

Figure 5-2 Illustration of the Processing Steps in Tomato Concentrates Finisher Screens with Different Diameter Openings were Used to Vary Pulp Particle Size and Content (Tanglertpaibul and Rao, 1987a).

Figure 5-3 Particle Size Distributions of 21 Brix Tomato Concentrates (top) Derived from Using 0.69 and 0.84 mm Finisher Screens, and in Serum Obtained from a Commercial Concentrate after Centrifugation at 100,000 X g for 1 h (bottom) (Yoo and Rao, 1996).

Rao et al. (1981) studied the influence of temperature and total solids content (c) on the apparent viscosity at 100 s (i a,ioo) of tomato concentrates prepared from the varieties grown at the New York State Agricultural Experiment Station Nova, New Yorker, 475, 934 hot break process, and 934 cold break process. The results of... 

Figure 5-12 Plot of the Pulp Content versus the Apparent Viscosity at 100 s of Tomato Concentrates (Tanglertpaibul and Rao, 1987b) Illustrates the Important Role of Pulp Content. The meaningless negative intercept Indicates that the linear relationship cannot be extended to low pulp contents.

Thus, an useful general result is that the viscosity of tomato concentrates can be scaled by the factor (totalsolids) -. For example, at a fixed temperature, one can predict the viscosity 2 of a tomato concentrate having the concentration C2 from the magnirnde i of a concentrate of the same variety having the concentration c from the relationship ... 

Dynamic rheological and creep compliance, J(t), data were obtained on tomato concentrates made from Pinto 696 hot-break juice prepared and two finisher screens having holes of diameter 0.69 mm (0.027 in) and 0.84 mm (0.033 in) were used (Yoo and Rao, 1996) the finisher was operated at 1000 rpm. The magnitudes of G and G ... 

F re 5-13 Log-log Plot of the Apparent Viscosity at 100 s versus Total Solids of Tomato Concentrates from 475 and New Yorker Tomatoes Using Hot-Break Juice the Slopes of the Lines were 2.4 and 2.5, Respectively. 

Figure 5-17 Modified Cox-Merz Plot for Tomato Concentrates (Rao and Cooley, 1992).

Figure 5-19 Texture Map of Structured Foods in which Values of the Static (S) and Dynamic (D) Yield Stresses Determined Using the Vane Method at Different Shear Rates were Plotted Against the Corresponding Values of the Angular Deformations. Products studied apple sauce—AS, ketchup—KH, mustard—MF, and tomato concentrate— TD. Based on unpublished data Genovese and Rao (2005).

Al viar, M. and Reid, D. S. 1990. Determination of rheological behavior of tomato concentrates using back extrusion. J. Food Set. 55 554-555. 

Fito, P. J., Clemente, G., and Sanz, F. J. 1983. Rheological behaviour of tomato concentrates hot break and cold break.. 7 Food Eng. 2 51-62. 

Somsrivichai, T. 1986. A study on rheological properties of tomato concentrates as affected by concentration methods, processing conditions, and pulp content, Ph.D. thesis, Cornell University, Ithaca, NY. 

Tanglertpaibul, T. and Rao, M. A. 1987a. Rheological properties of tomato concentrates as affected by particle size and methods of concentration. J. Food Sci. 52 141-145. 

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