Main food constituents

Starch and fatty acids are the main food constituents of biomass. Sugar is derived from starch by hydrolysis or directly by extraction from sugar cane or beet. Fermentation converts sugars into alcohol that can be directly used as fuel, or in principle can be used as the raw material of a bioreftnery plant for further upgrading. Triglycerides, derived from oil seeds, are used to be converted into biodiesel through transesterification processes (Fig. 1.14). 

Four types of interaction between matter and radiation are under discussion - the photo effect, the Compton effect, the pair formation effect and the spurs model. In the following sections changes of the main food constituents (lipids, carbohydrates and proteins) will be summarized. 

Food products contain thousands of compounds — some of nutritive value — nonnutritive components, numerous additives, substances formed during processing, and pesticide residues. Their safety is of utmost importance for human health protection, including cancer risk assessment. In order to evaluate the carcinogenicity of individual food constituents and their mixtures, often of unknown chemical structure, as well as the impact of cooking procedures, short-term reliable and inexpensive tests are necessary. Since cancer risk associated with chemical compounds is thought to stem mainly from their ability to induce mutations, mutagenicity... 

Adminstration via the oral route has been, and still is, the most popular and convenient route for patient therapeutics. However, even though it is the most convenient route, it is not the simplest route, as the barriers of the gastro-intestinal (GI) tract are in many cases difficult to circumvent. The main barriers of the GI tract to systemic delivery are the environment in the stomach and intestinal lumen, the presence of different enzymes, the physical barrier of the epithelium and the liver extraction. These barriers are of functional importance for the organism in controlling intake of water, electrolytes and food constituents and still remain a complete barrier to harmful organisms such as bacteria, viruses and toxic compounds. 

The thermal generation of flavor is a very essential process for the "taste" of many different foodstuffs, e.g. cocoa, coffee, bread, meat. The resulting aromas are formed through non-enzymatic reactions mainly with carbohydrates, lipids, amino acids (proteins), and vitamins under the influence of heat. Thiamin (vitamin B ) and the amino acids, cysteine and methionine, belong to those food constituents which act as flavor precursors in thermal reactions. The role of thiamin as a potent flavor precursor is related to its chemical structure which consists of a thiazole as well as a pyrimidine moiety. The thermal degradation of this heterocyclic constituent leads to very reactive intermediates which are able to react directly to highly odoriferous flavor compounds or with degradation products of amino acids or carbohydrates. 

Fats and oils are important food constituents. Their nutritional, chemical, and physical properties are influenced by the position of fatty adds, their chain length, and the degree of unsaturation. Usually, lipases are used to obtain modified fats with nutritionally improved properties and they provide high value fats such as cocoa butter that contains palmitic and stearic acids. Commercial lipases are mainly employed in the dairy industry for flavor enhancement in cheese (Mase et al., 2010 Omar et al., 1986), the acceleration of cheese ripening (Fox et al., 1996 Kheadr et al., 2002), the manufacture of cheeselike products, and the Upolysis of butterfat and cream (Purko et al., 1952 Seitz, 1974). Lipases release short-chain fatty acids that develop a tangy flavor and medium chain fatty acids that give a soapy taste to the end product (Sharma et al., 2011). 

Qualitative and quantitative determinations of phenolie acids, especially the combined forms, have been significantly improved during the last two decades, allowing one to draw a general picture of their distribution in fruits and vegetables and flieir importance as food constituents. In the comprehensive reviews on these topics that have already been pubUshed [1-5] most of the oldest references may be found. In the present review, our attention is focused on the presence and content of phenolic acids in fruits (mainly fleshy fruits with then-seeds) and vegetables, and on the main parameters fliat can modify them. 

Besides nutrients, foods contain many substances that influence the food sensory impression and its organoleptic properties. These food constituents are known as sensoriaUy active compounds. They determine the sensory value (quality) of foods, inducing an olfactory sensation (perception), which is described as the aroma, odour and smell, gustative perception, which is the taste, visual perception, which is the colour, haptic (tactile) perception, which is the touch and feel, and auditorial perception, which is the sound. The olfactory sensation is derived from odour-active compounds and the gustative perception from taste-active compounds. Flavour is the sensory impression determined by the chemical senses of both taste and smell and is caused by flavour-active food components. Haptic sensation is the texture, which is affected mainly by high molecular weight compounds, such as proteins and polysaccharides, often referred to collectively as hydrocoUoids. Geometric aspects of texture that evoke both haptic and visual sensations symbolise the terms appearance and shape. 

As one of the main structural constituents of biological membranes, PLs play a crucial role in the biochemistry and physiology of cells. PLs have also found plications in numerous industries. For example, PLs are often used as emulsifier, stabilizer and wetting and dispersing agents in the food industry. Pharmaceutical and cosmetic industries utilize PLs in liposomal encapsulation of active ingredients for enhanced delivery and bioavailability (Gabizon et al, 1997). 

A great majority of the aroma compounds produced in fermented foods result from the activity of microorganisms. They derive from the conversion of food constituents via a series of biochemical reactions mainly catalyzed by microbial enzymes, although some of the enzymes either present in the raw material or added during food processing also have a role in the transformation. A few non-enzymatic reactions also occur, but they involve some coirpounds of microbial origin. 

Foodbome off-flavor is mainly caused by concentration shifts in aroma-active food constituents. This is much more difficult to handle due to the subtle changes that finally result in an unbalanced aroma. The warmed-over flavor... 

Besides water, the diet must provide metabolic fuels (mainly carbohydrates and lipids), protein (for growth and turnover of tissue proteins), fiber (for roughage), minerals (elements with specific metabolic functions), and vitamins and essential fatty acids (organic compounds needed in small amounts for essential metabolic and physiologic functions). The polysaccharides, tri-acylglycerols, and proteins that make up the bulk of the diet must be hydrolyzed to their constituent monosaccharides, fatty acids, and amino acids, respectively, before absorption and utilization. Minerals and vitamins must be released from the complex matrix of food before they can be absorbed and utifized. 

Komit6 for Levnedsmidler (NMKL)]. The standard presents a universal validation approach for chemical analytical methods in the food sector. This includes methods for the main constituents and also for trace components. Therefore, the NMKL procedure focuses on primary validation parameters, such as specificity, calibration, trueness, precision, LOD or LOQ and does not refer to special requirements of pesticide residue analysis. 

The three most important constituents of FYM are nitrogen, phosphate and potash. Additionally, there are the bulky organic parts derived mainly from the straw and the part of the food that has resisted digestion. Granstedt (2002) showed that the majority of the N (about 90%) in farmyard manure served to maintain the soil humus store and the long term capacity to supply nutrients. 

In the case of an excipient that contains a mixture of constituents, qualitative and quantitative details of the composition should be provided (other than for flavoring or aromatic products, which must state the information only qualitatively provided there is a suitable method for ensuring consistency of composition and of the presence of the main ingredients and any carriers, with relevant references to purity criteria such as those established by the World Health Organization Food and Agriculture Organization). 

A product manufactured in Japan as Alo mixture (Anomalously Linked Oligosaccharides) contains mainly a range of IMOS (glucose, isomaltose, and panose as principal constituents). It is produced from starch as substrate by the action of alpha-amylase, beta-amylase, and a transglucosidase. It is claimed to have favorable properties for application in the food industry.143... 

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