Food, lecithin application

Instant foods. Lecithin has been used as a wetting agent and emulsifier in instant foods. Foods including cocoa powder, instant drinks, instant cocoa and flavored coffee, powdered protein drinks, coffee whiteners, instant puddings, cake mixes, and instant toppings are widely employed applications for specific lecithins. The most common method to incorporate lecithin is as an external coating on the powder particles. The particular lecithin to be employed largely depends on the hydrophilicity or lipophilicity of the powder system (7). 

Canned food emulsion. Another emulsification application for lecithins is in canned pet foods. Lecithin can help maintain homogeneity within the ingredient mixture during pumping to the cans, can reduce fat capping and crystallizing within the can, and can keep gravies and sauces consistent and smooth, without separation while stored in the cans. Lecithin is used at 0.25% to 0.75% of the canned pet food formula to achieve these effects (315). 

With the excellent release properties of lecithin, lubrication would seem like a natural area for its use. Indeed, lecithin has been used as an emulsifier to stabilize oil and water metal-cutting fluids (466). Incorporation of lecithin in the lubricant for forming sheet metal products can improve the electrostatic application properties of the lubricant, especially for food contact applications (467). Soaking valve seals in a solution containing lecithin impregnates the rubber and imparts improved lubrication (468). As with other areas discussed, modification of the lecithin for the... 

Table 10.7 Survey of lecithin application in selected foods...

Recent developments in the area of oils and fats has led to the production of specialty lipids from novel sources such as fruit seeds, nuts, and other minor plant sources. In addition, preparation of structured lipids for a myriad of applications has been of interest. Minor components of oils and fats may be isolated during processing and used as nutraceutical and functional food ingredients. Examples are lecithin, phytosterols, tocopherols, and tocotrienols, among others. Obviously, the health-promoting potential of such products is also of interest. 

Commercial lecithin is an important coproduct of edible oil processing because of its dietary significance and multifaceted functionality in food systems and industrial applications. Unless indicated otherwise, the term lecithin will denote the commercial designation throughout the text in this chapter. 

Solvent-extracted rapeseed oil has been found to contain the highest level of phosphorus. For this reason, it is common practice to degum solvent-extracted oil or the mixed crude oil from pressing and subsequent solvent-extraction. As the double-zero rapeseed varieties such as canola became available, the applications of rapeseed lecithin have developed positively. Where at first rapeseed lecithin was applied as an emulsifier and energy component in animal feed, the recent concerns about GMO soybean varieties in some parts of the world have increased the market value of the softseed lecithins for food applications (45). The phospholipid composition is similar to soybean lecithin with variations due to crop and processing conditions. The rapeseed phospholipid compositions in Table 12 have been confirmed by recent data, whereas the soybean lecithin composition in... 

Modified lecithins. Lecithins may be modified chemically, e.g., hydrogenation, hydroxylation, acetylation, and by enzymatic hydrolysis, to produce products with improved heat resistance, emulsifying properties, and increased dispersibility in aqueous systems (7, 58, 59). One of the more important products is hydroxylated lecithin, which is easily and quickly dispersed in water and, in many instances, has fat-emulsifying properties superior to the natural product. Hydroxylated lecithin is approved for food applications under Title 21 of the Code of Federal Regulations 172.814 (1998) (60). 

HI. The level of HI matter is one measure of the purity of lecithin products. HI matter usually consists of residual fiber, but also particulate contaminants that may be introduced during processing (e.g., filter aids). The level of HI matter in crude lecithin should never exceed 0.3% and rarely exceeds 0.1%. HI matter in lecithin is detrimental to clarity and use in specific applications. HI is measured by an official Food Chemicals Codex (FCC) (1996) method (54) or by AOCS Official Method Ja 3-87 (77). 

The most common modifications of lecithin and the intended physical/functional alterations are shown in Table 20 (31). The range of physical/functional properties available in commercial lecithins is listed in Table 21 (31). These changes in lecithin allow for the basic lecithin obtained from soybean oil to be converted to various emulsifier products having a wide variety of food, feed, and industrial applications. Reviews describing chemical reactions for phospholipid modifications intended to obtain specific functionalities include those of Eichberg (89), Hawthorn and Kemp (90), Kuksis (91), Pryde (86), Snyder (92), Strickland (87), and Van Dee-nen and DeHaas (93). 

Commercial lecithins are multifunctional food ingredients. The combined hydrophilic and hpophihc properties of phospholipid molecules give them surface-active effects in many applications. As surfactants, they can exhibit a variety of functions common to other surfactants while they also have unique functionalities of their own. 

Commercial lecithin products that were sold many decades ago for applications such as chocolate and confectionery products, margarine, bakery goods, pasta products, textiles, insecticides, and paints are still active today because of their emulsifying, wetting, colloidal, antioxidant, and physiological properties. Lecithin s multifunctional properties and its natural status make it an ideal food ingredient. The major applications and functional properties of lecithin products are shown in Table 25 (7). 

Highly filtered lecithins for use in health food applications. 

Solid particle dispersions (Sols). Many lecithin products are still the best and most effective surfactants for dispersing sols. This seems to be because of lecithin s affinity for solids—liquid surface interfaces. Phospholipids seem particularly attracted to particles containing metals and metal salts. Examples of food sols include some liquid chocolates, instant drinks, frosting mixes, pigmented foods, and others. The nonfood applications include paints, inks, and other pigmented coatings. 

Lecithins can be dissolved in oil, dispersed in water, or used as is, in release applications. Oil-free lecithins can be dry blended into breading, coatings, and spice or seasoning mixes for release of the coated food product from the food-contact surface. In food products that have a high surface area-to-volume ratio, like pancakes or fortune cookies, lecithin can be added directly to the product formulation to achieve release from the cooking/baking surface. Effective release depends on... 

General food applications of lecithin include margarine, confections, snack foods, soups, instant foods, bakery products, simulated dairy products, processed meat/poultry/seafood products, and dietary apphcations. The most widespread uses of crude lecithin products are in confections and margarine (7, 174). 

Pan and food release agents. Lecithin-based release agents are employed in many applications such as frozen waffle manufacture, bakery products, pizza baking, and pasta products. Most industrial griddle frying fats are formulated with lecithin, solely for its release functionalities (7). The products may be spray- or brush-applied to achieve a thin film capable of promoting easy release of baked items from pans and belts. Bakery release agents may contain 2-6% lecithin in a variety of oil bases, and they may also be formulated with particulate matter to provide an additional mechanical release. 

Continuous, multipurpose ovens that are used to precook foods may use water-filled dip tanks for cleaning and rinsing the conveyor belt. An aqueous release system, containing a water-dispersible lecithin, is added to the dip tank to facilitate release of the food from the oven belt, as well as promote better rinsing and cleaning during cooking. A 10% aqueous dispersion of lecithin is commonly used for this application (224). 

Producing bland fluid lecithins is possible by redispersing the de-oiled lecithin in clean oils that have been properly refined and deodorized. Lecithin flavors are not typically a problem in food applications because lecithins are used in most foods at low levels. Laboratory tests have shown that in finished food formulations, lecithins can either accentuate or reduce the flavor intensity of salt, acids, and some spices. However, lecithin flavors can penetrate bland dairy-based systems. Studies have shown that 0.25% de-oiled lecithin could be detected in cottage cheese (31). 

Lecithin may also find a significant home in applications of fertilizers or growth promoters. Lecithin that has been acidified with propionic acid can significantly enhance the performance of some plant growth modifiers (393). With continued emphasis on environmentally friendly agrochemicals, and concern about pesticide residues in the food supply, the potential for lecithin in agriculture appears poised for growth. 

There is no industry-wide reporting of lecithin sales in specihc application areas, and so the exact percentage breakdown of uses is difficult to determine. This problem is also complicated by the fact that as much as 30 0% of the domestic market involves hundreds of small volume users who are serviced by distributors (56). Additionally, some customers may have both food and nonfood applications for lecithin. 

For the most part, the greatest percentage of lecithin is used in foods. The second highest use is in animal feeds, followed by industrial applications. Paints and other coatings consume a major portion of the nonfood lecithin. Pharmaceuticals, including dietary supplements, and inks and cosmetics, however, also consume significant portions. 

The European reaction to traces of GMO DNA in foods has markedly affected the uses of phospholipids in food and health applications. The consumers right to know, and ingredient users avoidance of GM products, has led to a decrease in soybean and corn lecithin usage, with a shift to the usage of soft-seed lecithins (rapeseed and sunflower) that are non-GMO. 

Just as in some food uses, some of the nonfood applications of lecithin are in mature market areas such as paints and inks. Judging from patent activity, however, growth in some areas seems reasonably assured. 

In recent years, pharmaceutical patents accounted for almost 25% of the nonfood patent activity. Pharmaceutical applications, particularly those involving liposomes, should require increasing quantities of refined lecithins. An increased demand for lecithin as a dietary supplement is also anticipated, as the result of dietary reference intakes being established for choline. Besides being a multifunctional food ingredient, lecithin has the benefit of being a widely recognized health food. 

Lecithins are used in a wide variety of pharmaceutical applications see Table I. They are also used in cosmetics and food products. 

Some oil-soluble emulsifiers affect the crystallization process and development of polymorphic forms of fats (4-8). Sucrose fatty acid ester or sucrose polyesters (SPE) and lecithins are well-known food emulsifiers (9,10). The main characteristics of lecithins and SPE useful in food applications are their oil-in-water and water-in-oil emulsifying properties, that result in dispersion with condensed milk and coffee whitener, and prevention of blooming in candy products and chocolate (7,9-11). But there are very few reports about two effects of SPE on the crystallization of fats and oils, i.e., enhancement and inhibition (12,13). 

Similar studies have also been performed by the research group of Charbit in Marseilles (61,62) in which fine PPL particles were formed by decompression using the SAS process. The focus of this research was to develop drug delivery systems, but it would equally applicable to the functional food area. Typically, a 2 wt% solution of soy-derived lecithin is... 

The utilization of soybean lecithins is reviewed by Schneider (1986). Table 2.12 summarizes the most common applications in the food, feed, cosmetic, and pharmaceutical industries. The food industry relies on lecithin in bakery, beverage, and confectionery product development because of its functionalities. 

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