Isolation, functional properties and potential use of protein preparations from lupin.

Protein isolates were prepared by extraction with diluted NaOH (resulting the highest yield) and precipitation with HCl from lupin seeds grown in Egypt and Hungary. Protein content, amino acid composition, biological value and functional properties of isolates were studied. The proteins were high in lysine but relatively low in sulfur-containing amino acids. Good solubility and moderate emulsifying, foaming and gel-forming properties of isolates were observed. Enrichment of fruit- and vegetable-based baby foods with these isolates resulted in products with excellent organoleptic properties and moderate biological value. Additional enrichment with small quantities of methionine increased significantly the biological value without any negative changes of organoleptic characteristics.

Isolation and study of the functional properties of pea proteins.

Proteins of pea seeds were isolated after defatting with hexane using alkaline (0.1 M sodium hydroxide) extraction and acid (HCl) precipitation. Concentrates were also prepared by hexane extraction and ethanolic extraction (pH = 5). Gross chemical composition amino acid content and functional properties (solubility profile, emulsifying--and foaming properties, water--and oil absorption) were studied. The results were compared with the same parameters of soy and lupin protein products. Although the majority of functional characteristics of isolates were lower in comparison to soy isolates, pea protein concentrate and isolate could be successfully used in bakery products for enrichment in protein and improvement of biological value. Their utilization as meat protein substitute in some Frankfurter type sausages is also possibly.

Biochemical studies of some non-conventional sources of proteins. Part 7. Effect of detoxification treatments on the nutritional quality of apricot kernels.

Detoxification of apricot kernels by soaking in distilled water and ammonium hydroxide for 30 h at 47 degrees C decreased the total protein, non-protein nitrogen, total ash, glucose, sucrose, minerals, non-essential amino acids, polar amino acids, acidic amino acids, aromatic amino acids, antinutritional factors, hydrocyanic acid, tannins and phytic acid. On the other hand, removal of toxic and bitter compounds from apricot kernels increased the relative content of crude fibre, starch, total essential amino acids. Higher in-vitro protein digestibility and biological value was also observed. Generally, the detoxified apricot kernels were nutritionally well balanced. Utilization and incorporation of detoxified apricot kernel flours in food products is completely safe from the toxicity point of view.

The effect of ethanol in the separation of wheat gliadins by CM- and DEAE-cellulose chromatography.

The effect of ethanol on the fractionation of gliadin by cellulose-based ion exchange column chromatography was studied. Ten peaks have been separated on DEAE- and 12 peaks on CM-cellulose column using a complex elution technique. By SDS-polyacrylamide gel electrophoresis of the separated fractions, it was observed that ethanol incorporated into the eluent improved the resolution of some fractions. Some of the peaks gave only 2 or 3 protein bands in electrophoregrams. Since ethanol does not affect the reproducibility in the two types of chromatographic medium, the method seems to be suitable for purification of gliadin fractions in large quantities.

Biochemical studies of some non conventional sources of protein. Part 4. The proteins of mango waste stone kernels.

The gross chemical composition, protein content and amino acid composition of mango stone kernels of four Egyptian varieties (Ewsi, Hendi, Fonso and Timour) were investigated. Carbohydrates are the main components of the seed. The protein content varies between 5.0 and 7.2% and the ether extract ranged from 10.8% to 13.6%. High glutamic acid, aspartic acid and leucine content and low concentration of sulfur-containing amino acids are characteristic for the proteins of mango kernels. Lysine level is also low, the concentration of other essential amino acids is acceptable. Sulfur-containing amino acids are the first limiting ones followed by lysine and threonine.

Macrocyclic trichothecene toxins produced by Stachybotrys atra strains isolated in Middle Europe.

A total of 17 strains of Stachybotrys atra isolated in Hungary and Czechoslovakia were cultured on Sabouraud agar, and the toxins produced by them were chemically analyzed by gas-liquid chromatography, high-pressure liquid chromatography, and mass spectroscopy. Furthermore, brine shrimp (Artemia salina) bioassay was used for the determination of toxicity of the compounds examined. Macrocyclic trichothecenes (satratoxins H and G, roridin E, and verrucarin J as well as two other unidentified macrocyclic trichothecenes) were found in all of the cultures tested. The identities of satratoxins H and G, roridin E, and verrucarin J were qualitatively determined by high-pressure liquid chromatography and gas-liquid chromatography. The ratio of satratoxins H and G and roridin E was found to be similar in each of the strains tested, but the amount of verrucarin J found was different in each of them. One of the unidentified macrocyclic trichothecenes was equivalent to the compound isolated by Harrach et al. (Harrach et al., Appl. Environ. Microbiol. 41:1428-1433, 1981). The other one proved to be a newly isolated macrocyclic trichothecene toxin. Stachybotryotoxicosis, one of the oldest mycotoxicoses known, and a serious problem in Middle Europe (Gy. Danko, Magy. Allatorv. Lapja 31:226-232, 1976), is believed to be caused by macrocyclic trichothecene toxins produced by Stachybotrys atra (R. M. Eppley, in Rodricks et al., ed., Mycotoxins in Human and Animal Health, p. 285-293, 1977). Forty years ago, the death of animals in the Soviet Union was associated with this fungus (C. U. Ruhliada, in Proceedings of the All-Union Sci. and Tech. Conf., p. 47-51, 1980).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative study on the amino acids composition in three local Phaseolus vulgaris seeds varieties.

The overall amino acid composition of the three varieties of Phaseolus vulgaris seeds were similar. All had a relative deficiency in the sulphur-containing amino acids, moreover, there was a negative correlation between sulphur amino acid content and the percentage of seed proteins. The lysine content of the Phaseolus seeds was relatively high, the amount ranged from 8.05 to 8.63 g/16 g N. Tryptophan was slightly higher for Giza variety than the others. The highest levels of free amino acids were recorded for Contender variety and Swissblan one. Cystine, phenylalanine and tyrosine were absent from the extracts of the three varieties.

Simultaneous detection of some fusariotoxins by gas-liquid chromatography.

A method was developed for the simultaneous determination of 6 Fusarium mycotoxins (deoxynivalenol, diacetoxyscirpenol, HT-2 toxin, T-2 toxin, fusarenon-x, and zearalenone). Cereal samples were first extracted with ethyl acetate, then with a mixture of methanol-water. The crude extracts were combined and purified by silica gel chromatography. The purified extract was reacted with BSTFA (N,O-bis(trimethylsilyl)-trifluoroacetamide) to form the derivative, and chromatographed on an SE-52 wall-coated open tubular column. Kováts' retention index was determined for the 6 mycotoxins investigated. Recoveries and standard deviations were determined for pure toxin mixed in cereal. Recovery was 70-80%; relative standard deviation was 10-18%. The method developed was applied to different cereal samples.

[Determination of vitamin D3 in premixes and mixed feeds]. / Uber die Bestimmung von Vitamin D3 in Praemixen und Futtermischungen

The authors developed a two-dimensional thin-layer chromatographic method for the qualitative and quantitative determination of vitamin D3 in premixes and mixed feeds. The procedure permits to determine I.U. = 0.128 micrograms of vitamin D3. The method is illustrated by the description of the analyses of 3 premixes and 5 mixed feeds.

[Rheological properties of wheat gluten and their relation to molecular parameters]. / Rheologische Eigenschaften von Weizenkleber und ihre Beziehungen zu molekularen Parametern

In the light of the general results of protein chemistry and of the interrelationships up to now established, it is stated that the factors which determine the mechanical properties are complex in nature. Though the amino-acid composition (cystine content, amino acids with hydrophobic side-chains) and the ratio of the wheat gluten fractions (ratio of high molecular protein components to low-molecular ones) exert some effect on the rheological properties, the linkages and the interactions between the different fractions play the main role in the development of the mechanical properties of the gluten. Among the various linkages and interactions which occur in protein architecture, the disulphide linkages, the hydrogen bonds (amido group, primary amino group) and the hydrophobic interactions (side-chains of proline, leucine, isoleucine, glutamine, etc.) are of great importance. The complex evaluation of data about the content of disulphide linkages, the degree of amidation of the glutamic and aspartic acids and the amount of amino acids with hydrophobic side-chain gives a significant insight which might be of practical value.

[Toxin production by Fusarium species and occurrence of the toxins in agricultural products]. / Toxinbildung bei Fusarium-Arten und Vorkommen der Toxine in landwirtschaftlichen Produkten

In rainy autumnal weather and unfavourable storage conditions, certain agricultural products may be severely infested with Fusarium species also in Hungary. Since 1970 the authors have detected more than 200 Fusarium infestations in maize, wheat and mixed fodder. The Fusarium toxins were detected thin-layer chromatographically after extraction with chloroform and purification by means of solumn chromatography. Apart from F-2 (zearalenone) which is the most frequent toxin, other ultraviolet active toxic compounds were disclosed. Of the latter, the compounds F-3 and F-4 were isolated; their infra-red spectra were determined. From the results obtained, it may be concluded that these compounds have structures which resemble that of zearalenone and that they produce toxic effects.