Food water content

Food Water content," %(mass) Freezing Point" "C Above r. eezini... 

Food Water Content, % (mass) Temperature, T C Density, p kg/m Thermal Conductivity, k W/m K Thermal Diffusivity, a mVs Specific Heat, Cp kjfkg K... 

Water is an important component of animal foods. It contributes to the water requirements of animals and dilutes the nutrient content of foods. Water content varies widely between foods. 

Food Water content (%) Food Water content (%)... 

Water Activity. The rates of chemical reactions as well as microbial and en2yme activities related to food deterioration have been linked to the activity of water (qv) in food. Water activity, at any selected temperature, can be measured by determining the equiUbrium relative humidity surrounding the food. This water activity is different from the moisture content of the food as measured by standard moisture tests (4). 

Calcium Hypochlorite. High assay calcium hypochlorite [7778-54-3] was first commercialized in the United States in 1928 by Mathieson Alkali Works, Inc. (now Olin Corp.) under the trade name HTH. It is now produced by two additional manufacturers in North America (Table 5). Historically, it usually contained about 1% water and 70—74% av CI2, so-called anhydrous product, but in 1970, a hydrated product was introduced (234). It is similar in composition to anhydrous Ca(OCl)2 except for its higher water content of about 6—12% and a slightly lower available chlorine content. This product has improved resistance to accidental initiation of self-sustained decomposition by a Ht match, a Ht cigarette, or a small amount of organic contamination. U.S. production in the 1990s consists primarily of partially hydrated Ca(OCl)2, which is sold as a 65% av CI2 product mainly for swimming pool use. Calcium hypochlorite is also sold as a 50% av CI2 product as a sanitizer used by dairy and food industries and in the home, and as a 32% product for mildew control. 

Those with a normal diet take in food in the forms of carbohydrates, fats and proteins. Because it has a low water content and produces so many ATP molecules, fat yields 9.3 Calories per gram while carbohydrates and proteins yield less than half as much (4.1 and 4.3 calorics per gi-am respectively). Thus, we get a huge number of calories from a small quantity of fat eaten. The average person in the United States has a diet with 50 percent of the calories in the form of carbohydrates, 35 percent in the form of fat and 15 percent in the form of protein. We need about 1 gram of protein per kilogram of body weight per day to replace body proteins that are broken down. A 70 kg person... 

Raman spectroscopy is well suited for food analysis because the high water content of food that is a disadvantage for IR spectroscopy does not disturb Raman spectroscopy. 

Mateo, R. and Bosch-Reig, F. (1998). Classification of Spanish unifloral honeys by discriminant analysis of electrical conductivity, color, water content, sugars, and pH. /. Agric. Food Chem. 46, 393 00. 

The second requirement is that enforcement methods for food must be validated by an independent laboratory [independent laboratory validation (ILV)]. The sample set is identical with the general sample set (see Section 4.1). If the method is identical for all four crop groups (mentioned at the beginning of the section), it may be sufficient to perform the ILV for plant materials with a minimum of two matrices, one of them with a high water content. In the case of food of animal origin, the ILV should be performed with at least two of the matrices milk, egg, meat, and, if appropriate, fat. 

E7 Extraction in the presence of large amounts of fat Plant and animal fats with low water content, if the Umit of determination is not sufficient with E6, and dry food with a fat content exceeding 2.5 g/100 g Edible fats and oUs, wheat and rye germs, oats, nuts, oUseed... 

Exposure Levels in Humans. Although some data on the levels of americium in human tissues exposed to natural background levels (food, water, and air) are available, few measurements have been made on the americium content in human tissues. The principal source of information about occupationally exposed individuals is the U.S. Transuranium and Uranium Registries (USTUR) Tissue Program and database, established to document levels and distribution of uranium and transuranium isotopes in human tissues for occupationally exposed workers (USTUR 1999). Several major database files are available. 

Unique radiolytical products (URP) in irradiated food are usually formed by the secondary reactions of water radicals, eh, H, and OH, and to a lesser extent by the direct action of radiation, especially for foods with considerable water content. Due... 

Riedel, L. Enthalpie-water content diagram for lean beef (also valid for other meats with fat content below 4 %). Recommendations for the processing and handling of frozen foods, p. 28 and 29. International Institute of Refrigeration 75 Paris 17e, France, 2. ed 1972... 

The storability of the dried product depends to a large extend on the selected type, e. g. strawberries, carrots and green beans [4.7]. For meat, the fat content can be important. Karel [4.8] studied the influence of the water content in stored dried food, and found that not only was the amount of water of influence, but also the kind of bond to the solids. This link can be described by adsorption isotherms, as shown in Fig. 4.1. In food technology, the bond of water is often given by the term water activity, aw ... 

Food materials (ingredients or whole systems) can be composed of matter in one, two, or all three physical states solid (crystalline or amorphous or a combination of both), liquid, and gas. The crystalline state is an equilibrium solid state, whereas the amorphous glassy state is nonequilibrium solid state. The main transitions that occur between the physical states of materials of importance to foods are summarized by Roos and Karel (1991) and Roos (2002). The most important parameters affecting the physical state of foods, as well as their physicochemical properties and transition temperatures, are temperature, time, and water content (Slade and Levine, 1988 Roos, 1995). Pressure is not included in this list, as food materials usually exist under constant pressure conditions. 

Using the time-dependent aspect of state diagrams, Roos (2003) illustrated the effects of temperature, water activity, or water content on relaxation times and relative rates of mechanical changes in amorphous systems (Figure 36). This diagram can be considered as a type of mobility map, where mobility increases (relaxation time decreases) as temperature and/or water content/activity increases. Le Meste et al. (2002) suggested the establishment of mobility maps for food materials showing characteristic relaxation times for different types of molecular motions as a function of temperature and water content. 

Labuza, T.P., Tannenbaum, S.R., and Karel, M. 1970. Water content and stability of low moisture and intermediate moisture foods. Food Technol. 24, 543-550. 

Adjusting the physical chemical composition of food by reducing water content or adding water activity-lowering agents. 

Gunning, Y.M.. Parker. R.. Ring. S.G.. Rigby. N.M.. Wegg, B., and Blake, A. Phase behavior and component partitioning in low water content amorphous carbohydrates and their potential impact on encapsulation of flavors, J. Agric. Food Chem., 48(2) 395-399, 2000. 

External excitatory and inhibitory stimuli for acceptance or rejection of food are modified by the internal condition of the insect (e.g., hunger). This modification can cause a given stimulus to produce different responses, depending upon the internal condition of the insect. After host acceptance, there are still obstacles that the insect must overcome in order to survive, grow, and reproduce. These hurdles include allelochemicals that block nutrient availability, defenses of susceptible plants, poor balance of essential nutrients, and less than optimal water content. Neonate larvae may be far more sensitive to some of these obstacles than older ones. 

---