Phytate process

Soybean concentrate production involves the removal of soluble carbohydrates, peptides, phytates, ash, and substances contributing undesirable flavors from defatted flakes after solvent extraction of the oil. Typical concentrate production processes include moist heat treatment to insolubilize proteins, followed by aqueous extraction of soluble constituents aqueous alcohol extraction and dilute aqueous acid extraction at pH 4.5. 

The composition of the resulting soy product is shown on Table V, where it is seen that the protein content was unchanged, whereas raffinose, stachyose and phytate were almost removed, and the amount of dietary fibres was improved. This demonstrates that the availability of relatively pure pectinolytic enzymes, like the used RGase B, opens up for the new types of soy processes and products. 

Phytate (myo-inositol hexaphosphate Fig. 15.3, structure 33) is found in many food species and can be considered as a phytochemical. Its role in the plant is primarily as a phosphate store in seeds, but it is found in other tissues as well, for example, tubers (Harland et al., 2004). Phytate and its hydrolysis products are anti-nutrients that chelate metal ions and thus reduce their bioavailability (Persson et al., 1998 House, 1999). This is particularly a problem with cereal grains, but pre-processing can improve mineral absorption from these foods (Agte and Joshi, 1997). There is some concern that high phytate foods could also contain higher levels of toxic heavy metals caused by natural accumulation. Plants also contain phytate-degrading enzymes that can also influence metal ion bioavailability (Viveros et al., 2000). 

Agte V V and Joshi S R (1997), Effect of traditional food processing on phytate degradation in wheat and millets , J Agric Food Chem, 45,1659-1661. 

The occupation of all available coordination sites by phytate suppresses other iron-mediated processes, such as lipid peroxidation ( 0). Figure 6 demonstrates that 0.24 mM phytate prevents the peroxidation of arachidonic acid driven by ascorbic acid and iron, whereas substantial amounts of malondialdehyde arise in the presence of free iron or of an iron-ADP chelate. 

The obliteration of these iron-dependent oxidative processes by phytate suggests that this ubiquitous and abundant plant component functions as a natural antioxidant, preventing oxidative damage during storage of seeds. Surface treatment with phytic acid of various fruits and vegetables preserved their color, texture and flavor (7). Thus, dietary phytate may be a superior substitute for presently employed food preservatives, many of which pose significant health hazards. Additional applications of phytic acid are summarized in a recent review (34). 

By virtue of rendering iron catalytically inactive, dietary phytate may also suppress the incidence of colonic cancer (J2j>). Intestinal aerobic bacteria and/or minor inflammatory events generate substantial amounts of O27 leading to OH formation and lipid peroxidation. These two processes are thought to be important elements in tissue injury which occurs during inflammation. This argument is compatible with the observation that colonic cancer is frequently preceded, or accompanied, by pigmentation of the colonic epithelium lipofuscin, a byproduct of lipid... 

Other workers (115-124 for example) have also centered their efforts on the role of phytic acid on zinc and iron bioavailabiliy from both soy and wheat products. It has been suggested (120) that the phytate-to-zinc molar ratio could be used to predict zinc bioavailability in high-phytate foods. Several groups (115, 117), including ours (113), 1 least partially supporT this hypothesis. However, recent work from our laboratory (112) involving soy protein of similar phytate-to-zinc molar ratios clearly demonstrates that zinc bioavailability is also altered by food processing. In this study, zinc from neutralized soy concentrates and isolates was shown to be less available to the rat than was the corresponding acid-precipitated products. This is unfortunate as alkaline conditions are commonly utilized for soy and other plant proteins to obtain beneficial functional properties. 

Unstabilized bran and polish have been used almost exclusively for animal feed, due to the bitter flavor that develops from the lipolytic action of enzymes on the oil found in them. However, development of a thermal process that inactivates the lipases has resulted in a stabilized rice bran product that is suitable for the food industry. The impressive nutritional qualities of the oil, fiber, carbohydrate and proteins of rice bran have made it a valuable food material. Removal of fiber from the bran by physical K,J7or enzymic1819 processes produces a milk-like product having desirable nutritional and functional properties. The nutritional composition of the rice bran milk product described by California Natural Products has been shown to match the nutritional requirements of an infant formula. Originally, the anti-nutritional factor of the residual phytates was of concern. However, as of 2005, phytase enzymes are suitable for use to break down these phytates. 

One very important additional concurrent enzyme process has been developed by Alko and Dorr-Oliver (28). This is the steeping of corn with phytase in combination with a T. reesii cellulase rich in side activities. (This enzyme combination was originally developed under the Econase 434 name for use in pig feeds the breakdown of phvtate by phytase released the phosphorus bound by the phytate. This amounts to 50% of the phosphate in corn, for example.) Anyone working with Corn... 

In order to formulate a mechanism of action of phytate on zinc homeostasis, certain conditions must be fulfilled 1) The process must occur In the gastrointestinal tract since phytate Is not absorbed except for small amounts by birds 2) calcium must be a tertiary component in the total process but there must be some reaction without excessive amounts of calcium 3) certain chelating compounds such as EDTA must be capable of competing with the process and make some zinc available for absorption or reabsorption and 4) There must be some explanation for the data which indicates that 40% or more of the dietary pool may be available for absorption (, 49). All these conditions are satisfied by the following formula which is an expression of the "Law of Mass Action" ... 

Our laboratories have been concerned with the role that unit food processing operations play in the bioavailability of zinc from complete diets. Soybean foods have served as models for the evaluation of processing effects upon both endogenous and added zinc. Below are described results from both rat bioassays and in vitro tests for zinc bioavailability. Prediction of zinc bioavailability from soy-containing diets is far more complex than an analysis of phytate and zinc molar ratios. 

In the absence of mechanisms to accelerate phytic acid hydrolysis, the complexant will clearly persist in the environment for a long time. However, enzyme catalyzed phytate hydrolysis is known to be much faster than the thermal reaction (27). Thus biological activity may accelerate the hydrolysis reaction in soils. A recent report indicates that phytic acid is rapidly hydrolyzed by both aerobic and anaerobic microbiological processes in environmental samples (22). Complete phytate hydrolysis was observed in less than 40 days in anaerobic sediments, while half the available phosphate was released in 60 days under aerobic conditions (22). 

However, tamarind seeds have low levels of phytic acid comparable that of lima bean (Egbe and Akinyele, 1990, cited in 4)). Phytic acid decreases bioavailability of certain minerals and may interfere with the ntihzation of proteins dne to the formation of phytate-protein and phytate-mineial-protein complexes and also inhibits the digestive enzymes (Reddy et al, 1982, cited in 4)). The phytate conld, however, be snbstantially eliminated by processing methods snch as soaking and antoclaving (Reddy et al, 1982, cited in 4)). 

Use Chelation of heavy metals in processing of animal fats and vegetable oils, mst inhibitor, preparation of phytate salts, metal cleaning, treatment of hard water, nutrient. 

Antinutrient factor removal Processed meats. Special diets. Specific protein inhibitors of proteolytic enzymes and amylases. Phytate. Gossypol. Nucleic acid. ... 

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