Relative abundance and inhibitory distribution of protease inhibitors in potato juice from cv. Elkana

Enzymatic extractability of soybean meal proteins and carbohydrates: Heat and humidity effects

To study the incomplete enzymatic extractability of proteins and carbohydrates of thermally treated soybean meals, one unheated and three heat-treated soybean meals were produced. To obtain truly enzyme-resistant material, the meals were extracted by a repeated hydrolysis procedure using excessive concentrations of different combinations of...

Dephosphorylation-induced structural changes in β-casein and its amphiphilic fragment in relation to emulsion properties

To promote the understanding of the relationship between emulsifying and molecular properties of proteins/peptides, intact β-casein (βCN) and its amphipathic fragment, i.e. βCN (1-105/107) were dephosphorylated. Dephosphorylation was found not to change significantly their emulsifying properties. Since it is known that the structure of proteins...

The effect of pH on heat denaturation and gel forming properties of soy proteins

This study is focussed on the influence of pH on the gel forming properties of soy protein isolate and purified glycinin in relation to denaturation and aggregation. At pH 7.6 more fine-stranded gels were formed characterised by low G' values, and a smooth, slightly turbid appearance, whereas at pH 3.8 coarse gels were obtained with a high...

Heat denaturation of soy glycinin: Influence of pH and ionic strength on molecular structure

The 7S/11S glycinin equilibrium as found in Lakemond et al. (J. Agric. Food Chem. 2000, 48, xxxxxxxx) at ambient temperatures influences heat denaturation. It is found that the 7S form of glycinin denatures at a lower temperature than the 11S form, as demonstrated by a combination of calorimetric (DSC) and circular dichroism (CD) experiments. At...

Soy glycinin Influence of pH and ionic strength on solubility and molecular structure at ambient temperatures

This study describes the relationship between the solubility of glycinin, a major soy protein, and its structural properties at a quaternary, tertiary, and secondary folding level under conditions representative for food products. When the ionic strength is lowered from 0.5 to 0.2 or 0.03, the basic polypeptides shift more to the exterior of the...

The effect of storage of whole potatoes of three cultivars on the patatin and protease inhibitor content; a study using capillary electrophoresis and MALDI-TOF mass spectrometry

The content and biological activity of patatin and the protease inhibitors of molecular size 20-22 kDa present in whole potato tubers were investigated as a function of storage time. The amount of buffer-extractable protein decreased gradually during storage of whole potatoes of the cultivars Bintje and Desiree for 47 weeks whereas, for Elkana,...

Isolation and characterization of patatin isoforms

Patatin has, so far, been considered a homogeneous group of proteins. A comparison of the isoforms in terms of structural properties or stability has not been reported. A method to obtain various isoform fractions as well as a comparison of the physicochemical properties of these pools is presented. Patatin could be separated in four isoform...

The adsorption-induced secondary structure of β-casein and of distinct parts of its sequence in relation to foam and emulsion properties

Changes in the secondary structure upon adsorption of β-casein (βCN) and of distinct parts of its sequence were investigated by far-ultraviolet circular dichroism in order to find suggested relationships with foam and emulsion-forming and -stabilising properties of the same protein/peptides. A teflon/water interface was used as a model system...

The pH Dependence of the Structural Stability of Patatin

This paper presents the structural stability of patatin, the major potato (Solanum tuberosum cv. Bintje) tuber protein. Using far- and near-ultraviolet circular dichroism and fluorescence spectroscopy, the conformation of patatin was studied under various conditions as a function of temperature. Patatin is a protein that unfolds partly due to...

Heat-induced conformational changes of patatin, the major potato tuber protein

This paper presents a first structural characterization of isolated patatin, the major potato tuber protein, at ambient and elevated temperatures. Isolated patatin at room temperature is a highly structured molecule at both secondary and tertiary levels. It is estimated from far-ultraviolet circular dichroism data that about 33% of the residues...

Variation in the degree of d-xylose substitution in arabinoxylans extracted from a European wheat flour

Total water-extractable arabinoxylan from flour of the European bread making wheat cultivar Camp Remy was fractionated by ethanol precipitation. Both 1H-NMR spectroscopy and methylation analysis of the isolated arabinoxylan fractions showed wide variation in the degree of xylose substitution. More highly substituted arabinoxylan fractions were...

Mild isolation of water-insoluble cell wall material from wheat flour: Composition of fractions obtained with emphasis on non-starch polysaccharides