A proteomic approach to study protein variation in GM durum wheat in relation to technological properties of semolina.

Genetic manipulation of durum wheats by tobacco rab-1 genes influence the trafficking of gluten proteins through the secretory system by up- or down-regulating the transport step from the ER to the Golgi apparatus which may in turn modify functional performance of the grain. Gluten proteins were extracted from two genetically manipulated lines - Svevo B730 1-1 and Ofanto B688 1-2 - and their control lines and were analyzed by two dimensional gel electrophoresis. When the two-dimensional maps were compared by image analysis no significant differences between the GM line with an up-regulated trafficking containing the wild type tobacco rab1 (Svevo B730 1-1) and its control (Svevo control). By contrast, significant differences were found between the GM line with a down-regulated trafficking due to the tobacco rab1 mutant form (Ofanto B688 1-2) and its control (Ofanto control). Of the new protein spots detected in the down-regulated Ofanto B688 1-2 map, only a beta-amylase was identified. The remaining spots were susceptible to chymotripsin action but not to trypsin one, as in the case of the gluten protein. Rheological measurements showed that gluten quality was enhanced in the down-regulated Ofanto B688 1-2 without an increase in the amount of gluten. Proteomics is a useful and powerful tool for investigating protein changes in GMOs and in understanding events in food science and technology.

Carotenoid and chlorophyll-derived compounds in some wine grapes grown in Apulian region.

Carotenoid compounds in wine grapes (Chardonnay, Merlot, Primitivo, Negroamaro) grown in Apulian region were investigated by chromatographic and spectrometric analyses. Cis-isomers of lutein and beta-carotene (9Z, 9'Z-lutein and 9Z-beta-carotene) and 5,6-epoxyxanthophylls were detected: 9'Z-neoxanthin, violaxanthin, and 5,6-epoxylutein. Moreover, zeaxanthin was efficiently resolved from lutein by a selective factor > 1 (alpha= 1.06) and was found in high amounts (50 to 300 microg/kg) in the grape extracts analyzed in 3 y of study (2006 to 2008). At grape maturity, beta-carotene had concentration approximately 2-to 4-fold higher than (all-E)-lutein in all varieties. Because carotenoids are potential precursors of aroma compounds, it was determined carotenoids change DeltaC (microg/kg), from the difference of total carotenoids concentration between veraison and maturity. Chardonnay and Merlot had the highest DeltaC values and principal component analysis showed that they were characterized by 5,6-epoxyxanthophylls derivatives and zeaxanthin, lutein, and beta-carotene derivatives, respectively. An important effect of vintage on DeltaC values in the analyzed grapes was also observed. A strong positive correlation was determined between DeltaC and temperature data that seem to be responsible for the difference of DeltaC in the Chardonnay and Merlot compared to the Primitivo and Negroamaro varieties.

Rapid screening for anthocyanins and anthocyanin dimers in crude grape extracts by high performance liquid chromatography coupled with diode array detection and tandem mass spectrometry.

A rapid and efficient method using high performance liquid chromatography coupled with diode array detection and tandem mass spectrometry (HPLC-DAD-MS/MS) for fast screening large numbers of anthocyanins and anthocyanin dimers in different grape skin extracts, without further sample clean-up procedures, was developed. A good separation of most detected anthocyanins was achieved in a run time of 15 min. Identification of anthocyanin pigments required a combination of several information: UV-vis spectra, MS and MS/MS spectra, and elution pattern. Many compounds have been here detected for the first time and their structures tentatively elucidated.