Pears composition

Eutectoid structures are like eutectic structures, but much finer in scale. The original solid decomposes into two others, both with compositions which differ from the original, and in the form (usually) of fine, parallel plates. To allow this, atoms of B must diffuse away from the A-rich plates and A atoms must diffuse in the opposite direction, as shown in Fig. A1.40. Taking the eutectoid decomposition of iron as an example, carbon must diffuse to the carbon-rich FejC plates, and away from the (carbon-poor) a-plates, just ahead of the interface. The colony of plates then grows to the right, consuming the austenite (y). The eutectoid structure in iron has a special name it is called pearlite (because it has a pearly look). The micrograph (Fig. A1.41) shows pearlite. 

Askar, A. and El-Samahy, S.K., Chemical composition of prickly pear fruits, Dtsch. Lebensm Rdsch., 77, 279, 1981. 

Ferreira D, Guyot S, Mamet N, Delgadillo I, Renard CM and Coimbra MA. 2002. Composition of phenolic compounds in a Portuguese pear (Pyrus communis L. var. S. Bartolomeu) and changes after sun-drying. 

Other studies further indicate that the occurrence of endrin in the U.S. food supply is very low. In a 1990-91 FDA survey of pesticide residues in milk representing most of the U.S. supply consumed in metropolitan areas, endrin was detected at trace levels (0.0005-0.001 ppm [0.5-1.0 ppb]) in only 2 of 806 composite samples (one sample each from Atlanta, Georgia and Dover, Delaware) (Trotter and Dickerson 1993). In another statistically based FDA study in 1992-93, endrin was not found as a violative residue in any of 710 domestic or 949 imported pear samples (Roy et al. 1995). Endrin was not reported among the pesticides detected in a 1994 FDA survey of pesticide levels in 160 samples of catfish, crayfish, shrimp, trout, salmon, oysters, and various other species from important aquaculture areas of the United States (FDA 1995). Comparable results were found in similar studies conducted by the FDA in 1990-93 (FDA 1995). 

Amiot, M.J. et al., Influence of cultivar, maturity stage and storage conditions on phenolic composition and enzymatic browning of pear fruits, J. Agric. Food Chem., 43, 1132, 1995. 

Spanos, G.A. and Wrolstad, R.E., Influence of variety, maturity, processing and storage on the phenolic composition of pear juice, J. Agric. Food Chem., 38, 817, 1990. 

All organisms are made up of chemicals. There is a common collection of several hundreds of substances that are produced by all living organisms. However, hrmdreds of thousands of different chemicals are also produced by plants and microbes, with each species producing its own characteristic mix. This much larger class of chemicals, often called Natural Products (NPs), are clearly not essential for life, but their production must bring some benefit to the producer. The different NP composition of pears and apples, for example, explains why these two fruits taste different. The difference in NP composition of lemons and roses gives each species its characteristic smell. Even within a species, the NP composition can vary hence, individual varieties of apples or pears can have distinctive flavours. 

The main difference between botrytized wines and other nonfortified sweet wines, for example, late-harvest wines, icewines (eiswein), or straw wines, is the extreme range and richness of the aroma compounds produced by Botrytis. Marked differences also exist in some other components (e.g., glycerol, acid composition), due to the microbial activity. According to the descriptors most often applied to these wines, they are characterized by peach, apricot, pear, quince, raisin, and honey flavors, combined with distinctive "botrytis or roti aspects. Another typical feature of botrytized wines is their high acid contents. These prevent them from appearing cloying, even if the sugar content is commonly over 200 g/1. 

Typical compositions of sand pear and plum vermouths are given in Tables 8.7 and 8.8. 

In the first case, the chemical reaction practically does not disturb the adsorption-desorption equilibrium between the colloidal particle adsorption layer and the liquid phase. The composition of the adsorption layer during the MO reduction may be expressed in terms of the reagents initial concentrations and the current [MO] value. In the second case, the reaction volume of the colloidal particle is limited by its adsorption layer, which composition during MO reduction may be found from the known [reag]0 and [MO]. In the intermediate case, the current composition of the colloidal particle adsorption layer and hence the cp([pear]o, [MO]) value will explicitly depend on Io-... 

Properties Pearly, shining, transparent scales or white powder slightly acid, metallic taste. Composition varies. Soluble in water slightly soluble in alcohol. 

Processing and Storage Influences on the Chemical Composition and Quality of Apple, Pear, and Grape Juice Concentrates... 

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