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The impact of ammonia solution (NH 4 OH) mild pretreatment (pH 9.5, 25 °C/0.5–2 h), followed by sodium hydroxide extraction (0.1 M NaOH, 60 °C/1–4 h), on the wheat bran (WB) arabinoxylan (AX) extractability, the molecular features of the isolated polysaccharides and their rheological behavior were investigated. AX isolates, obtained from WB treated solely with NH 4 OH, exhibited lower Mw and a lower degree of xylan backbone substitution (arabinose/xylose ratio), compared to those obtained by combined alkali treatments (NH 4 OH/NaOH), as evaluated by HPLC-SEC-RI, FTIR and 1H NMR analyses. Swelling of bran cell walls, caused by NH 4 OH, resulted in crevices of the outer bran tissue layers, thus increasing AX extraction yields, as the ammonia pretreatment and NaOH extraction times were extended. 2D DOSY NMR experiments revealed the presence of individual populations exhibiting discrete diffusional characteristics, while in most cases, each population was further subdivided into two sub-populations composed mainly of chains of either monosubstituted or disubstituted anhydro-xylosyl residues, with the latter diffusing more slowly. The steady-shear viscosities of 4% aqueous AX dispersions were positively correlated primarily to the AX Mw, and secondarily to the arabinose/xylose ratio. Dynamic rheometry revealed that extraction only with NH 4 OH or water provided AX isolates capable of gelification due to oxidative coupling of feruloyl residues covalently attached on AX chains, as evidenced by FTIR, 1H NMR, and further confirmed by 2D DOSY NMR. Overall, these findings elucidated the structural heterogeneity of AX isolates obtained under varying alkali extraction regimes, along with their diversified rheological behavior. [Display omitted] • NH 4 OH pretreatment modified the structural and rheological properties of NaOH-extracted wheat bran (WB) arabinoxylans (AX). • NH 4 OH caused swelling and cracking of the bran outer layers, increasing AX extractability. • Combined NH 4 OH–NaOH extraction led to AX with higher Mw and A/X ratio than extraction using only NH 4 OH. • NMR analysis and 2D mapping showed a microheterogeneity in AX substitution patterns and Mw distribution. • Apparent viscosity of AX aqueous dispersions was positively correlated with their Mw and A/X ratio. [ABSTRACT FROM AUTHOR]

The potential application of apple pomace emulsions (APEs) as saturated fat replacers in biscuits was investigated by employing olive oil/water (35/65) emulsions enriched with 12.5–20.0% apple pomace residue (AP) and exploring their rheological properties and microstructure. A selected APE (with 15% AP) was used as margarine replacer in biscuits at 50–100% substitution levels and the biscuits quality attributes were examined using a multi-instrumental analytical approach; a full-fat biscuit (30% margarine) was tested as control. Firmness and spreadability work of APE, evaluated by large deformation mechanical testing, increased with increasing AP content. The elasticity and viscosity of the control biscuit dough as determined by rheometry were higher than their reduced-fat counterparts with APE. With increasing APE substitution level, the moisture and water activity increased, and a lower biscuit color lightness was noted, whereas the thickness did not significantly differ among the tested product formulations. Moreover, fracture strength, total phenolic (3,4-dihydroxybenzoic acid being predominant) content and antioxidant activity were greater for the APE-fortified biscuits than the control. SPME/GC–MS analysis revealed the presence of AP-derived volatile compounds, providing pungent, rancid and fruity notes in the APE-fortified biscuits. Nevertheless, the 50% margarine substituted biscuit received acceptable ratings for flavor notes, hardness, fragility and overall acceptability upon sensory evaluation. Slower rates of lipolysis (on biscuit weight basis) were also observed for the APE-fortified biscuits using an in vitro intestinal enzymatic digestion protocol. Overall, the APE appeared as an effective solid fat substitute in biscuits that improves their nutritional characteristics, while maintaining acceptable quality attributes. [Display omitted] • Apple pomace emulsion (APE) was used as saturated fat substitute in biscuits (BS). • The rheological properties of APE enhanced with rise of apple pomace level. • 50 & 70% margarine substitution did not affect the BS physical & textural features. • APE induced into BS volatile compounds related to pungent, rancid and fruity notes. • 50% margarine substitution by APE gave healthier and sensorially acceptable BS. [ABSTRACT FROM AUTHOR]

Emulsion gels are considered as an innovative approach to substitute shortenings and margarine in food formulations, e.g., bakery products. Cereal β-glucans are fiber-type constituents, well-known for their human health promoting effects, but also as effective viscosifiers for stabilization of emulsions and aqueous dispersions of solid particles. Barley emulsion gels (BEGs) were formulated with varying weight proportions of β-glucan-enriched (∼27%) barley flour/olive oil/water (from 13/10/77 to 31/30/39) and their physicochemical properties and microstructure as potential solid fat replacers in food formulations were examined. Changes in physical properties and structure of BEGs were monitored using dynamic rheometry, large deformation mechanical testing, differential scanning calorimetry and confocal microscopy during storage (4 °C for 7 days). The rheological tests showed a typical solid-like character for all BEGs (i.e., G' was greater than G'') without oil exudation. The gel strength of BEGs increased upon storage, whereas the thermal properties were dependent on composition and application of heat treatment during BEGs production. Moreover, the microstructure of BEGs revealed that protein particles are located around the surface of oil droplets in the 13/10/77 gels, while in the 31/30/39 formulation, both oil droplets and proteins were entrapped within a more compact hydrated β-glucan-starchy network matrix. The molecular weight of β-glucans (SEC-HPLC) isolated from BEGs was lower than that of β-glucan isolate obtained from the native barley flour. Overall, the multi-instrumental analytical approach employed herein was a suitable framework for evaluation of the physical properties of BEGs as potential solid fat substitutes in the production of healthier formulated products. [Display omitted] • Barley flour emulsion gels (BEGs) enriched with β-glucan were prepared at 25 and 60 °C. • The gel strength and elasticity increased with rise of barley flour and olive oil level, and cold storage. • Degradation of β-glucan was higher in BEGs prepared at 25 °C than that of 60 °C. • Starch gelatinization occurred only in BEGs with high water level prepared at 60 °C. • BEGs with various physical properties were made for use as fat substitutes in healthier products. [ABSTRACT FROM AUTHOR]

Wheat flour was substituted by flour from roasted chickpeas at 10–20% (flour basis) and a multi-instrumental analytical approach was employed to explore the dough rheological behavior of the composite starch-proteins hydrated networks, the quality attributes of the resultant breads, as well as the staling process. Fortifications with roasted chickpea flour at 15 and 20% level significantly increased dough viscosity and elasticity as showed by oscillatory and creep-recovery rheological tests, implying higher dough resistance to flow and deformation that resulted in breads with significantly lower specific volumes and harder crumb than the control (bread without chickpea flour). Moreover, at 20% substitution level, the staling kinetics of composite breads, as monitored by texture profile analysis, indicated a greater extent of crumb hardening at the end of storage, whereas the level of retrograded amylopectin in the crumb as assessed by calorimetry (DSC) did not differ among samples. Nevertheless, for bread with 20% chickpea flour, FTIR spectroscopy revealed a large increase in protein β-sheets and a further increment of such conformational change in the stored crumb, suggesting dehydration of gluten and its involvement in the staling process. Instead, formulations with 10% roasted chickpea flour did not exhibit any major influence on dough rheological behavior, as well as on textural attributes and bread staling. Furthermore, at 10% substitution of wheat flour by roasted chickpea flour, there was complete masking of the "grass-like" and reduced "beany" and "earthy" off-flavor notes in breads, as assessed by a trained panel, pointing to a product with high overall acceptability. [Display omitted] • Roasted chickpea flour (15 and 20%) increased wheat dough viscosity and elasticity. • Chickpea flour inclusion (15 & 20%) decreased bread volume and increased staling. • Chickpea addition (20%) increased protein β-sheets in fresh and staled wheat bread. • Roasted chickpea flour at 10% level had no effect on dough and bread properties. • Roasted chickpea flour at 10% eliminated legume off-flavors in composite breads. [ABSTRACT FROM AUTHOR]

Roasted yellow split pea (YSP) flours were used to substitute wheat flour, at 10–20% (flour basis) in wheat bread formulations. Rheometry showed that roasted YSP flour addition increased elasticity and resistance to deformation and flow of the composite doughs, particularly at 20% substitution; instead, at 10% addition (either raw or roasted YSP flour), there were no effects on dough rheology and bread textural properties. Breads fortified with roasted YSP flour at levels >10% exhibited lower loaf-specific volume and harder crumb compared to control (bread without YSP flour). Moreover, only breads with 20% roasted YSP flour displayed a significantly higher staling extent and rate, compared to control, as assessed by large deformation mechanical testing and calorimetry (starch retrogradation) of crumb preparations. This formulation also showed a large increase in β-sheets and β-turns at the expense of α-helix and random coil conformations in protein secondary structure as assessed by FTIR spectroscopy. Roasting of YSP effectively masked the "beany" and "grass-like" off-flavors of raw YSP flour at 10% substitution. Overall, roasted YSP flour at the 10% level was successfully incorporated into wheat bread formulations without adversely affecting dough rheology, bread texture, and shelf-life, resulting in final products with a pleasant flavor profile. [ABSTRACT FROM AUTHOR]