Detection of flour or farina from Triticum aestivum in macaroni by starch-gel electrophoresis of water-soluble proteins

A water-soluble protein component, A, has been found which appears without exception at a higher concentration in Triticum aestivum than in T. durum. Quantitation of A is achieved by referring the height of densitogram peak A to the height of peak B, which corresponds to a second component that is present in all varieties studied from both species. Extreme valúes of peak height ratio (PHR) in both species are tentatively established. On the basis of these valúes, the máximum and minimum possible contents of T. aestivum in a mixture are expressed as a function of PHR. All the varieties of T. aestivum studied are detected when they contribute more than 60% to the mixture. In over 90% of all possible binary combinations between varieties of T. aestivum and T. durum, the máximum proportion of undetected T. aestivum has been 30%

A New method for the estimation of common wheat (Triticum aestivum L.) in pasta products

An electrophoretic component ofthe chloroform-methanol (2:1) extractedproteins from common wheat endosperin is barely detected in durum wheat. This sharp interspecific difference is expressed in per cent units ofanother electrophoretic component which is present in both wheat species and designed protein ratio (PR). Macaroni production processing and/or. variations of milling yield do not significantly affect the PR. A linear relationship exists between PR and the % of common wheat in a known mixture. Tentative interspecific limits for PR are established from a survey of79 common wheat and 30 durum wheat variéties. Basedon these limits, máximum and mínimum possible common wheat contení in an unknown mixture is calculated as a funcí ion of PR

Detección y cuantificación de harinas de trigo común ("Triticum vulgare") en sémolas y pastas alimenticias

El método se basa en la detección y cuantificación de un componente designado CM, del extracto cloroformo-metanol del endaspermo de trigo o de productos derivados de él, cuyo control genético radica en el cromosoma ID de •Triticum Vulgarey que por tanto no se encuentra en «T. durum». El mencionado extracto,, al que se designa proteina CM, se fracciona por electroforesis sobre gel de almidón, y e] componente CM| se estima visualmente o se cuantifica densintométricamente

Identificación de productos de Triticum Aestivum en las pastas alimenticias. IV. Lipoproteínas solubles en éter de petróleo

Se ha establecido en trabajos anteriores (1-4) que, si bien el contenido en palmitato de sitosterol es un buen índice de la presencia de productos de Triticum aestivum en las pastas alimenticias, algunas variedades de dicha especie no podían ser detectadas debido a que su contenido en palmitato de sitosterol era similar al de las variedades de T. durum. La búsqueda de nuevas diferencias bioquímicas interespecíficas está justificada, no sólo por este hecho, sino también porque para obtener una buena aproximación en la determinación cuantitativa de productos de T. aestivum en las pastas alimenticias es necesario emplear más de un índice bioquímico, ya que todos ellos han de presentar cierta variabilidad intraespecífica

Site-directed mutagenesis and expression in Escherichia coli of WMAI-1, a wheat monomeric inhibitor of insect α-amylase

The wheat monomeric inhibitor WMAI-1 (syn. 0.28) produced inEscherichia coli using the pT7-7 expression ventor has the correct N-terminal sequence and the same electrophoretic mobility and specific activity towards the -amylase from the insectTenebrio molitor as the native WMAI-1 isolated from wheat. This confirms that the native inhibitor is not glycosylated and contradicts claims that a putative glycosyl moiety was essential for inhibition. Thirteen mutants have been obtained at six different sites. Substitution of the highly conserved N-terminal S by the sequence ARIRAR increased the pre-incubation time required for maximum activity. A similar result was obtained by insertion of GPRLPW after position 4, while insertion of EPRAPW at the same position rendered the inhibitor inactive. The substitution D/EGPRL and insertions DGP or D, at position 58, produced complete inactivation. All other mutations had only minor effects on activity

Estimation of Triticum aestivum in pasta flour: interspecific limits for sitosteryl palmitate content

Sitosteryl palmitate (SP) content of flour was shown to be not significantly affected by normal variations in milling yield. Since the distribution of fat in a wheat kernel does not follow the same pattern as does SP, it is preferable to consider SP content on the basis of DM content of the flour. A survey of 46 Triticum aestivum and 24 T. durum flours showed that the latter contained SP, but its level did not exceed 1.5 mg/100 g. T. aestivum varieties show a two-peak distribution, with the maxima at approximately 4 mg/100 g and at 12 mg/100 g, respectively. Three T. aestivum flours were within the T. durum range and three others were close to it. Limits for sitosteryl palmitate content in T. aestivum and T. durum were tentatively established at 16.5 mg/100 g and 1.5 mg/100 g respectively. Based on these limits, a method is proposed for the estimation of the minimum amount of T. Aestivum in a mixture

Distribution of sitosteryl palmitate in the wheat grain/Pie Verteilung von Sitosterylpalmitat im Weizenkorn

Sitosteryl palmitate content of most T. aestivum varieties is considerably higher than ^hat of T. durum. This sharp difference allows the semiquantitative determination of T, aestivum products when mixed with T. durum products such as semolina, flour or macaroni. Distribution of this substance in the wheat kernel has been investigated in order to check its influence on the estimated valúes for different products and mixtures» Nine fractions obtained by experimental milling, as well as the whole kernel, have been analize<? in three T. aestivum varieties and one T. durum. Puré germ and degerminated seed obtained by hand dissection also have been analized. A thin layer enromatography method on silica gel plates impregnated with silver nitrate, as previously described by us, has been employed in the sitosteryl palmitate determinations. Somewhat higher valúes are obtained for the germ as compared with endosperm, the content of the seed coats being lower. Considering the relative proportion of each fraction studied and their sitosteryl palmiíate content it can be concluded that variations within normal limits of extraction rate have no significant influence on sitosteryl palmitate content

Il palmitato di sitosterolo nelle varie parti del chicco di grano duro e tenero

II contenuto in palmitato di sitosterolo neMa maggior parte de-lie varietá di Triticum aestivum é considerevolmente piü elevato che nel Triticum durum. Questa netta differenza permette la determinazione semi-quantitativa del T. aestivum mescolato con prodotti di T. durum, come sémola, fariña o pasta. In base a r¡cerche su varietá di T. durum ed aestivum, si é stabilito che la porzione mínima di T. aestivum in una Tniscela é fúnzione del contenuto in palmitato di sitosterolo. E' stata studiata la di'stribuzione di questo composto nei chicchi di grano per determíname I'influenza su differenti miscele e prodotti. Sonó state analizzate nove frazioni ottenute con macinazione sperimentale, insieme a chicchi interi di due varietá di T. aestivum e di una di T. durum. Sonó stati anche analizzati il germe puro ed ¡I prodotto degerminato. Per la determinazione del palmitato di sitosterolo si é anche impiegata la cromatografía su strato sotti'Ie con supporto di gel di sílice impregnato con 'nitrato di argento. Per i I germe si sonó ottentiti valori piü alti rispetto airendosperma, essendo piü basso il contenuto in palmitato nel rivestimento del seme. Considerando il rapporto relativo alie frazioni studiate ed Ü rispettivo contenuto in palmitato di sitosterolo, si puó concludere che le variazioni della resa di macinazione entro limiti normali non hanno significativa influenza sul contenuto in palmitato

Nucleotide sequence of a cDNA encoding an α/β-type gliadin from hexaploid wheat (Triticum aestivum).

A cDNA clone was isolated from a library obtained from developing endosperm of cv. Chinese Spring which encoded an α/β-type gliadin that differs from previously described ones. The nucleotide sequence and deduced amino acid sequence of the new clone, designated MM1, are presented

cDNAs of a wheat tetrameric inhibitor of a-amylases

In the laboratory of M. Metzlaff, genome specific DNA probes from Hordeum vulgare were cloned and characterized by H. Junghans. Regarding repeated DNA sequences our further investigations will concéntrate on the proofof alien chromatin in the wheat -Ae. markgrafii crossing material and on the enlargement of the investigation to their distribution in Poaceae species