Food processing bioavailability

Form of iron Measured Food Processing Bioavailability Iron Source Major Result Reference... 

The release of a compound from the food matrix in which it is incorporated is a determining process for its bioavailability and is largely influenced by the physicochemical characteristics of the compound, the type of food matrix, the subcellular location of the compound in plant tissues, and the food processing. The, food matrix type greatly influences the compound bioaccessibility. 

Schlemmer U. Decker H. (1993) On the mechanism of the copper-pectin interaction. In proceedings of Bioavailability 93 Nutritional, Chemical and Food Processing Implications of Nutrient Availability. U. Schlemmer (Ed.). Ettlingen, May 9-12, 494-500. 

The good bioavailability of orally administered ciprofloxacin obviates the need for the more expensive intravenous formulation. I.v. ciprofloxacin is only given to patients who have severe sepsis or severe nausea and vomiting. Ciprofloxacin s elimination is 50% hepatic and 50% renal. Therefore, dose reduction is recommended only in case creatinine clearance drops to < 10 ml/min. Prevention of food-borne disease requires efforts at many levels. Monitoring safety of food processing, vector control, surveillance of outbreaks, education on personal hygiene and improving sanitation and access to safe water supplies are all necessary measures to reduce the incidence of GTI. 

Bioavailability can be influenced directly or indirectly by many physiological, pathological, chemical, nutritional, and processing conditions. Discussion in this chapter will be limited to unit food processing effects upon the bioavailability of nutrients from plant protein foods. The bioavailability of amino acids, carbohydrates, lipids, vitamins and minerals from processed foods will be selectively reviewed. Amino Acids... 

Recent review articles (, 104-109) have described general factors that affect mineral utilization from foods. General factors such as the digestibility of the food that supplies the mineral, chemical form of the element, dietary levels of other nutrients, presence of mineral chelators, particle size of the food or supplemented minerals and food processing conditions all play a role in the ultimate mineral bioavailability (104). Many unit food processing operations can be shown to directly or indirectly alter the level or chemical form of minerals or the association of minerals with other food components. 

Little agreement has been reached as to which dietary components or which food processes physiologially affect mineral availability. Many plant foods contain phytic acid, oxalic acid or other dietary fiber components that can be shown to chelate minerals. The effect of these dietary substances upon the final bioavailability of the mineral in question will depend upon the digestibility of the chelate (106). 

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. 

The conjugated forms of vitamin B6 appear to be less available than the six principal vitamers (102,104-106) a relative value of 58% has recently been suggested for PN-glycoside in humans (107). In addition, food processing and storage can induce changes that reduce the bioavailability of vitamin B6 (102). Thermal processing and low moisture conditions can induce reductive... 

Often overlooked in the evaluation of the effects of diet upon mineral availability is the role that food processing plays in the formation of or breaking of ligand-metal complexes. Several individual or unit processing steps are needed to produce a soy concentrate, a bread or a spray-dried egg white. Some or all steps may have a bearing upon final mineral bioavailability. Soy concentrate from company A is not produced in precisely the same manner as from company B. In fact, lot to lot variation for the same product may be quite variable, particularly in mineral content. 

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. 

This chapter mentions some iron chemistry Important to its bioavailability and the changes which may be induced by food processing. The reader may refer to the chapter by Spiro and Saltman (1) for a discussion of inorganic iron chemistry. This author has critically reviewed the iron sources used for food enrichment earlier (2). A good review of the chemistry of iron in myoglobin has been published by Livingston and Brown (3). Forth and Rummel (4) have made available an extensive review on iron absorption and factors which affect iron absorption. 

An extensive series of studies performed at the FDA Division of Nutrition established a wide range of bioavailabilities for the iron sources used in food enrichment (8-12). However, the rank in Table 11 was based on direct feeding of the iron source to test animals. The impact of food processing or of the food matrix on iron bioavailability is not apparent in these rankings. Large differences in bioavailability between iron sources will become smaller or change completely as a result of some types of processing, while other processes have little effect. 

Processed Food Type of Iron Added to Food Control Bioavailability of added iron vs. Control Test Type (species) Reference... 

Iron Profile. The studies reviewed in the section on the effect of processing on iron bioavailability suggest that bioavailability depends upon the iron source, the food matrix, and the nature of the food process. The question remains does the source, matrix or the process have an effect on the chemical form of iron, or iron profile. 

With respect to the mixed findings on fortification of cereals with free lysine, attention was drawn by the 2002 WHO/FAO/UNU Expert Consultation (2007) to the issue of Maillard reactions between amino acids, especially lysine, and sugars that can occur during food processing. Maillard reactions adversely affect the bioavailability of amino acids. Lysine, as a free amino acid, is particularly susceptible to loss through the Maillard reaction (Ajandouz and Puigserver, 1999). 

---