Zina Flagella

Changes in seed yield and oil fatty acid composition of high oleic sunflower (Helianthus annuus L.) hybrids in relation to the sowing date and the water regime

Sunflower is one of the most cultivated oil crops in the world. Recently, high oleic acid cultivars have been developed whose oil has higher oxidative stability and better dietary properties than standard genotypes. In Mediterranean environments where water deficit frequently occurs, early sowing and irrigation are used to overcome environmental constraints due to water scarcity. Since, in the literature, the data on the effect of these agronomic techniques on sunflower oil quality are scarce and contrasting, the aim of this paper was to evaluate the effect of the sowing time and the water regime on seed yield and oil quality of high oleic hybrids in a Mediterranean environment. For this purpose, two high oleic hybrids (Platon and Vyp70) sown in spring at two different dates were cultivated in southern Italy under two water regimes (irrigated and non-irrigated) in 1996 and 1997. Yield and its main components were positively affected by irrigation and by the earlier sowing date. With regard to fatty acid composition, a decrease in oleic and stearic acid and an increase in linoleic and palmitic acid were observed under irrigation. At early sowing, oleic and palmitic acid decreased whereas linoleic and stearic acid increased. The decrease in the oleic/linoleic acid ratio observed at early sowing and under irrigation, suggests a possible role of temperature on the activity of oleate desaturase in the developing seeds.

Seawater stress applied at germination affects mitochondrial function in durum wheat (Triticum durum) early seedlings

Seawater stress effects on mitochondrial ATP synthesis and membrane potential (ΔΨ) were investigated in germinating durum wheat seedlings under moderate (22% seawater osmolarity, -0.62 MPa) and severe (37% seawater osmolarity, -1.04 MPa) stress. To estimate the osmotic component of salt stress, mannitol solutions (0.25 and 0.42 m) iso-osmotic with the saline ones were used. Moderate stress intensity only delayed mean germination time (MGT), whereas higher seawater osmolarity reduced germination percentage as well. In contrast, Na+ and Cl- accumulation showed a sharp increase under moderate stress and only a small further increase under severe stress, which was more pronounced for Cl-. Only severe stress significantly damaged succinate-dependent oxidative phosphorylation, which may be related to the stress-induced alteration in inner mitochondrial membrane permeability, as indicated by changes in ΔΨ profiles. Proline-dependent oxidative phosphorylation, however, was inhibited under moderate stress. This suggests the occurrence of an adaptation mechanism leading to proline accumulation as an osmoprotectant. Moreover, both the osmotic and the toxic components of seawater stress were detrimental to oxidative phosphorylation. Damage to germination and MGT, in contrast, were mainly caused by osmotic stress. Therefore, mitochondrial function appears to be a more sensitive target of toxic stress than growth. In conclusion, the effects of seawater stress on mitochondrial ATP synthesis vary in relation to the substrate oxidised and stress level, inducing both adaptive responses and damage.

The maintenance of photosynthetic electron transport in relation to osmotic adjustment in durum wheat cultivars differing in drought resistance

Abstract The relationships between photosynthesis and osmotic adjustment (OA) under water stress are not yet well understood. Therefore, a possible association between the quantum yield of photosynthetic electron transport at the Photosystem II level (ΦPSII) and OA was evaluated in drought-stressed durum wheat plants in this paper. Four cultivars (cvs) differing in the degree of drought resistance as estimated by the ΦPSII maintenance, were grown in a growth chamber under two different water stress cycles; in both cases two stress intensities (moderate and severe) were used. Leaf water potential (ΨW), osmotic potential at full turgor (Ψπ100), ΦPSII and the efficiency of excitation capture by open Photosystem II reaction centres (ECPSII) were determined in the different experimental conditions, both in control and stressed plants. ΦPSII and ECPSII were evaluated by in vivo chlorophyll fluorescence analysis. ΦPSII showed a significant decrease only under severe water stress and for the drought susceptible cvs; on the other hand, ECPSII showed no change under the different water stress conditions. The percent decrease of ΦPSII under water deficit was confirmed to be a good indicator of drought resistance in durum wheat. OA was estimated as the difference in the Ψπ100 between leaves from water-stressed and well-watered plants. No relationship between the maintenance of the ΦPSII and OA under water deficit was observed in the adopted experimental conditions; this result is discussed in the light of the contrasting evidence in the literature.

Functional, textural and sensory properties of dry pasta supplemented with lyophilized tomato matrix or with durum wheat bran extracts produced by supercritical carbon dioxide or ultrasound

A study was carried out to produce functional pasta by adding bran aqueous extract (BW) and bran oleoresin (BO) obtained using ultrasound and supercritical CO2, respectively, or a powdery lyophilized tomato matrix (LT). The bioactive compounds, hydrophilic and lipophilic antioxidant activity (HAA and LAA) in vitro, were evaluated. BW supplementation did not improve antioxidant activity, whilst LT pasta showed unconventional taste and odor. BO pasta had good levels of tocochromanols (2551μg/100g pasta f.w.) and carotenoids (40.2μg/100g pasta f.w.), and the highest HAA and LAA. The oleoresin altered starch swelling and gluten network, as evidenced by scanning electron microscopy, therefore BO pasta had structural characteristics poor compared with the control (4.8% vs. 3.2% cooking loss), although this difference did not affect significantly overall sensory judgment (74 vs. 79 for BO and control, respectively). BO supplementation was most effective for increasing antioxidant activity without jeopardizing pasta quality.

Comparative analysis of gluten proteins in three durum wheat cultivars by a proteomic approach.

The gluten protein composition and expression level influence dough properties and are cultivar and environment dependent. To broaden the knowledge of the durum wheat gluten proteome, three cultivars were compared in two different growing seasons by a proteomic approach. Cultivar-specific and differentially expressed spots in the two years were identified by mass spectrometry. Significant differences were observed among the cultivars: Ofanto showed the lowest protein spot volumes in the high molecular weight (HMW) and low molecular weight (LMW) <35,000 regions and the highest in the LMW 48,000-35,000 region, Latino the lowest in the LMW 48,000-35,000 region, and Simeto an intermediate expression level in both LMW regions. In the warmer year the up-regulation of HMW glutenins, α-gliadins, and a globulin 3 protein and the down-expression of LMW glutenins and γ-gliadins were observed. Among the cultivars, Simeto showed the highest stability across the environments.

New tool to evaluate a comprehensive antioxidant activity in food extracts: bleaching of 4-nitroso-N,N-dimethylaniline catalyzed by soybean lipoxygenase-1.

In this study the 4-nitroso-N,N-dimethylaniline (RNO) bleaching associated with linoleic acid hydroperoxidation catalyzed by the soybean lipoxygenase (LOX)-1 isoenzyme (LOX/RNO reaction) was used to determine the antioxidant activity (AA) of hydrophilic and lipophilic pure antioxidant compounds and of mixtures of antioxidants extracted from durum wheat whole flour (DWWF). By means of a simple and rapid experimental protocol (about 3 min/assay), the LOX/RNO reaction may simultaneously detect many antioxidant functions (scavenging of some physiological radical species, iron ion reducing and chelating activities, inhibition of the pro-oxidant apoenzyme), thus providing a comprehensive AA evaluation. Consistently, the LOX/RNO assay was very sensitive to hydrophilic, lipophilic, and phenolic antioxidant extracts from DWWF, providing AA values at least 35 and 30 times higher than those by TEAC and ORAC methods, respectively. Moreover, the new method was able to highlight synergism (among extracts) 3 times more than the ORAC method, whereas TEAC did not measure synergism under our experimental conditions.

Differential Expression of Durum Wheat Gluten Proteome under Water Stress during Grain Filling.

Environmental stress during grain filling may affect wheat protein composition, thus influencing its final quality. A proteomic approach was used to evaluate changes in storage protein composition under water stress of two Italian durum wheat (Triticum turgidum ssp. durum) cultivars, Ciccio and Svevo. The high-molecular-weight glutenin region increased progressively in both cultivars and under two water regimens. The L48-35 region, corresponding to low-molecular-weight (LMW) glutenin subunits, increased slightly during grain development and decreased under water stress in both cultivars. In particular, an s-type LMW related to superior technological quality was down-expressed in the early-mid period in Svevo and in the mid-late period in Ciccio. Finally, the L<35 region, corresponding to gliadin-like proteins, decreased slightly during grain development and increased under stress in both cultivars. Several α-gliadins, associated with immunological potential, increased their expression under water stress, especially in Svevo in the early-mid stage of grain filling.

Evaluation of Phenolic Antioxidant Capacity in Grains of Modern and Old Durum Wheat Genotypes by the Novel QUENCHERABTS Approach

The QUENCHERABTS (QUick, Easy, New, CHEap and Reproducible) approach for antioxidant capacity (AC) determination is based on the direct reaction of 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation with fine solid food particles. So, it may resemble the antioxidant action in foods or in human gastrointestinal trait. Here, the QUENCHER approach was used to study AC of durum wheat (Triticum durum Desf.) grains. Firstly, it was assessed which kind of antioxidants determines QUENCHER response. This has been performed by comparing AC measured by QUENCHERABTS and that measured by classical TEACABTS (Trolox equivalent antioxidant capacity) in four different extracts from whole flour of 10 durum wheat varieties containing: lipophilic, hydrophilic, insoluble-bound phenolic (IBP) and free-soluble phenolic (FSP) compounds. QUENCHERABTS data were unrelated to AC of water-extractable antioxidants and weakly correlated (r = 0.405, P < 0.05) to AC of the lipophilic ones; on the contrary, QUENCHERABTS response was mainly related to AC of IBP (r = 0.907, P < 0.001) and to a lesser extent of FSP extracts (r = 0.747, P < 0.001). Consistently, correlation was also found with the phenolic content of IBP and FSP (r = 0.760, P < 0.001 and r = 0.522, P < 0.01, respectively), thus confirming that QUENCHERABTS assay mainly assesses AC due to IBP. So, this assay was used in a first screening study to compare AC of bioactive IBP of thirty-six genotypes/landraces covering a century of cultivation in Italy. Interestingly, no relevant AC difference between modern and old genotypes was found, thus suggesting that a century of plant breeding did not decrease phenol-dependent health potential in durum wheat.

Differences in gluten protein composition between old and modern durum wheat genotypes in relation to 20th century breeding in Italy

Graphical abstract

Antioxidant capacity of durum wheat large flour particles may be evaluated by QUENCHERABTS assay by adopting a proper calculation mode

Assessment of Antioxidant Capacity (AC) of foods is useful to consider cumulative/ synergistic action of all dietary antioxidants, thus providing a more integrated information than the simple sum of measurable antioxidants. Among the different AC assays, the QUENCHERABTS (QUick, Easy, New, CHEap and Reproducible) procedure is based on the direct reaction of ABTS•+ reagent with fine solid food particles without extraction of antioxidants. This assay is able to measure both soluble and insoluble antioxidants, that simultaneously come into contact with ABTS•+ molecules by either liquid–liquid or solid–liquid interactions, respectively. These interactions may change depending on the particle diameter. Usually, particles having 0.1–0.3 mm size are used. Here, AC was evaluated on whole flour (WF), derived from a mix of grains of ten durum wheat varieties, characterized by three different particle sizes: a smaller one, ≤0.2 mm (control, WF0.2), and two larger ones, ≤0.5 mm and ≤1 mm (WF0.5 and WF1, respectively)...