Chapter

Effects of Soybean Trypsin Inhibitor on Tissue Zinc in Weanling Male Long-Evans Rats

January 1988

DOI:10.1007/978-1-4613-0723-5_176

In book: Trace Elements in Man and Animals 6 (pp.501-502)

Authors:

U.S. Food and Drug Administration

Antinutritive components in raw soy flour include trypsin inhibitors (TI) and phytic acid (PA). PA increases dietary requirements for Zn and Mn when soy proteins are fed to animals. A Zn-PA-protein complex is responsible for effects on Zn (O’Dell and Savage, 1960). In diets containing PA from textured vegetable protein (from heated, defatted soy flour), supplementation with Zn overcomes adverse effects of PA on growth rate and prevents deficiency symptoms (Rader et al., 1986). TI in unheated soy flour causes pancreatic hypertrophy, hypersecretion of proteolytic enzymes, decreased growth, and reduced fat absorption when fed to rats. Reduced protein digestibility and loss of nitrogen due to excessive pancreatic secretion also contribute to the poor nutritive value of unheated soybeans. These problems are overcome by live steam treatment (toasting), which denatures TI (Rackis, 1978). Effects of TI per se on mineral bioavailability have been less extensively studied than have those of PA.

ResearchGate has not been able to resolve any citations for this publication.

Soybeans, chemistry and technology

Article

Effect of Phytic Acid on Zinc Availability.

Article

Mar 1960

Zinc in isolated soy protein is less available than that in casein. Zinc in a casein-phytic acid complex, which contains an amount of phytic acid comparable to that found in isolated soy protein, is also less available than that in untreated casein. Addition of calcium phytate to casein-gelatin type diet had little or no effect on zinc availability.

Trace Elements in Man and Animals - TEMA 5”

Jan 1978
458

J I Rader
S.-H Tao
C M Gaston
K A Wolnik
F L Fricke
M R S Fox
JI Rader

Chapter

The application of an in vitro method for mineral bioaccessibility estimation in the nutritional opt...

January 2017

Enteral formulas (EF) are complex food systems having all the necessary nutrients for complete human nourishment. However, there are components in EF that can interact with minerals, reducing their absorption and therefore EF nutritional quality. Dialyzability is an in vitro technique that can be used as an estimator of bioaccessibility of a particular mineral. It is the ratio of an element that ... [Show full abstract] diffuses through a semipermeable membrane during simulated gastrointestinal digestion after a period to allow equilibrium. In order to optimize mineral bioaccessibility of enteral formulas, the effects of soy protein (SP) and casein protein (CP) ratios (0, 50, and 100%), and polydextrose content (Px: 8.0, 16.5, and 25.0 g L-1) on Fe, Zn, and Ca bioaccessibility (%DFe, %DZn, and %DCa) were studied using the dialyzability method. Also, protein digestibility (%PD) was assayed. Experimental normal-protein (40 g L-1 protein) EF was developed and evaluated using a response surface design. Two control samples without Px and with only SP or CP were carried out. As an estimator of bioaccessibility for a particular mineral, the in vitro mineral dialyzability assay was used. Results appeared as SP content increased, %DFe (10.56-14.62%), %DZn (3.17-8.19%) and %PD (85.97-100%) decreased, probably due to the increased levels of phytic acid and trypsin inhibitors from SP isolate. %DCa (22.33 ± 22.99%) was not affected by any analyzed factors. Px did not affect any response variable in the design. However, it impaired mineral bioaccessibility of SP-EF compared with the same formulation without Px, although this effect was not observed for CP-EF, suggesting physicochemical interactions among nutrients affecting solubility were present in SP-Px-EF. The responses for an optimized enteral formula were: %DFe: 14.5; %DZn: 8.1; %DCa: 22.8 and %DP: 100.0. The use of the dialyzability assay as an indicator of mineral bioaccessibility contributes to defining special food formulas in such a way that they provide adequate bioavailable mineral quantity to achieve nutritional targets.

Article

Full-text available

Modification of the Soluble Protein Content of Heat-Processed Soybean Flour

September 2010 · Notulae Botanicae Horti Agrobotanici Cluj-Napoca

An important and frequently observed effect of food processing is the reduction of protein nutritive quality. Heat treatment of soybeans can reduce the activity of trypsin inhibitors and thereby improve protein digestibility. Overheating, however, may destroy or reduce the availability of certain heat sensitive amino acids and reduce the nutritional value of soy protein. The simplest criterion ... [Show full abstract] used for the characterization of proteins is their solubility in various media. The objective of this study was to evaluate the thermal effect on protein solubility of soybean flour (SBF). Heat-processed SBF was obtained in a forced air oven at 120ºC, and by exposing to microwaves at 2450 MHz frequency. Protein solubility was determined according to the procedure of Araba and Dale, based on the solubility of soybean proteins in 0.036 M KOH. The experimental data show that, whatever the heating process used, the heating time is negatively correlated with the protein solubility. To maintain a good nutritional quality to heated soybean flour, microwave treatment has to be shortly applied compared to cooking one.