Tomato texture

Consumer acceptance of fresh and processed fruits and vegetables is influenced by product appearance, flavor, aroma, and textural properties. Color is a key component that influences a consumer s initial perception of fruit and vegetable quality. Lycopene is the principal carotene in tomato fruit that imparts color. Analytical and sensory... 

Chapter HI relates to measurement of flow properties of foods that are primarily fluid in nature, unithi.i surveys the nature of viscosity and its relationship to foods. An overview of the various flow behaviors found in different fluid foods is presented. The concept of non-Newtonian foods is developed, along with methods for measurement of the complete flow curve. The quantitative or fundamental measurement of apparent shear viscosity of fluid foods with rotational viscometers or rheometers is described, unithi.2 describes two protocols for the measurement of non-Newtonian fluids. The first is for time-independent fluids, and the second is for time-dependent fluids. Both protocols use rotational rheometers, unit hi.3 describes a protocol for simple Newtonian fluids, which include aqueous solutions or oils. As rotational rheometers are new and expensive, many evaluations of fluid foods have been made with empirical methods. Such methods yield data that are not fundamental but are useful in comparing variations in consistency or texture of a food product, unit hi.4 describes a popular empirical method, the Bostwick Consistometer, which has been used to measure the consistency of tomato paste. It is a well-known method in the food industry and has also been used to evaluate other fruit pastes and juices as well. 

The texture of fruit pulp or tomato paste can be achieved in nonstandardized products, such as pizza sauces, through the introduction of texturizer starches. These are typically highly crosslinked starches that are subsequently drum dried. 

Native pectin esterases can be used for protecting and improving the texture and firmness of several processed fruits and vegetables these include apple slices (53), canned tomatoes (54), cauliflower (55), carrots (56), potatoes (56), beans (57) and peas (91). 

These regulations are likely to lead a conventional food manufacturer to adopt a tailored approach to organic recipe development. As an example, a careful scanning of the Regulation will show that only non-chemically modified starch is allowed, whereas very highly specific chemically modified starches are the norm in conventional processing. This is likely to mean that the development process will have to include examination of non-chemically modified alternatives. Another example is chopped tomatoes, normally used in recipe dishes in the conventional industry, which are treated with calcium in order to retain their texture this is not an option available to the organic manufacturer. 

Yoo, B. and Rao, M. A. 1994. Effect of unimodal particle size and pulp content on rheological properties of tomato puree. J. Texture Stud. 25 421-436. 

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).

Kokini, J. L., Bistany, K., Poole, M., and Stier, E. 1982. Use of mass transfer theory to predict viscosity-sweetness interactions of fructose and sucrose solutions containing tomato solids. J. Texture Stud. 13 187-200. 

S ome of the common characteristics of night ades ate alternating, simple leaves that are often hairy in texture and may have a strong odor. The size and ape of the leaves, however, vary greatly within the family. The flowers of these plants generally have a tubular shape, oflen with five petals attached, as in the petunia. The stamens of the flowers are connected at their base. When the ovary of the flower matures into a fruit, it is either flediy like a tomato, or a dry fruit called a capsule, as in the tobacco plant. 

A coffeehouse setting with cheery walls and oddly shaped tables, Naked Earth serves complex food in a simple setting. For lunch, try their no-tuna sandwich - tofu, celery, onion, sesame seed, seaweed, and a mix of herbs and spices on your choice of bread. Someone s finally invented a well-textured tuna sandwich that doesn t taste fishy Another sandwich option is the sun-dried tomato hummus. Sandwiches are served with sprouts, lettuce, tomatoes and a side of homemade cole slaw made with red cabbage and tofu mayonnaise. They also offer a daily soup and salad special. On my visit, the lasagna looked excellent - layered seitan and tofu ricotta with peppers and mushrooms. 

Black Nightshade is a low-branching annual, 1 to 2 tall with triangular stems that bear oval, thin-textured, alternate leaves with wavy margins. The tiny white flowers, borne in drooping clusters on lateral stalks between the leaves, resemble tomato flowers. The berry fruit is green when immature, purplish-black when ripe. 

The ability of metal ions to modify the texture of fruit and vegetable tissue has been studied since 1939, when Kertesz (l) found that calcium ions improved the firmness of tomatoes. A very simplified generalization of the effects of metal ions on fruit and vegetable texture is that monovalent cations, usually Na+ and K, cause tissue softening. Examples of this softening effect include results with peas (2.31, dried peas (4), carrots (5), potatoes (6) and green beans (7). On the other hand calcium, a divalent cation,... 

Tangwongchai, R., Ledward, D.A., and Ames, J. A. 2000. Effect of high pressure treatment on the texture of cherry tomato. Journal of Agricultural and Food Chemistry 1434-1441. 

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