Sustainable Recovery of Phenolic Compounds from Distilled Rosemary By-Product Using Green Extraction Methods: Optimization, Comparison, and Antioxidant Activity.

Rosemary solid distillation waste (SWR), a by-product of the essential oil industry, represents an important source of phenolic antioxidants. Green technologies such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and accelerated solvent extraction (ASE) of phenolic compounds from SWR were optimized as valorization routes to maximize yield, rosmarinic acid (RMA), carnosol (CARO) and carnosic acid (CARA) contents. Response surface methodology was used in this context, with ethanol concentration (X1), extraction temperature (X2), and time (X3) being the independent variables. A second-order polynomial model was fitted to the data, and multiple regression analysis and analysis of variance were used to determine model fitness and optimal conditions. Ethanol concentration was the most influential extraction parameter, affecting phenolic compounds, while the influence of other parameters was moderate. The optimized conditions were as follows: X1: 67.4, 80.0, and 59.0%, X2: 70, 51, and 125 °C, and X3: 15, 10, and 7 min for MAE, UAE, and ASE, respectively. A comparison of optimized MAE, UAE, and ASE with conventional Soxhlet extraction techniques indicated that ASE provided a higher extraction yield and content of phenolic compounds. However, UAE represented the best process from an environmental point of view, allowing an improved extraction of phenolics from SWR with high energy efficiency and low energy costs.

A sourdough process based on fermented chickpea extract as leavening and anti-staling agent for improving the quality of gluten-free breads.

The use of a sourdough (SD) preparation based on a fermented chickpea extract (FCE) starter as a leavening and anti-staling agent in gluten-free breads was explored in this study. The FCE starter was prepared by a submerged fermentation (at 37 °C for 15 h) of coarsely ground chickpeas and the gluten-free bread formulations, based on rice and corn flours, were made using a rice sourdough produced with the FCE starter as additional leavening agent; the FCE-SD breads and samples containing merely baker's yeast as microbial leavener (control) were both prepared at three different levels of added water, i.e., 85, 92 and 100% (flour weight basis). The loaf specific volume significantly (p < 0.05) increased with sourdough inclusion into batters and by increasing the amount of added water. Moreover, inclusion of sourdough into the gluten-free formulations resulted in a finer porous crumb macrostructure and a lower crust moisture content than control breads. Upon bread storage (25 °C for 5 days), water migration from crumb to crust was noted. Staling events were also monitored by compression testing and differential scanning calorimetry, showing an increase in crumb firmness and the apparent melting enthalpy (ΔH) of retrograded amylopectin during bread storage; the values for both parameters decreased with inclusion of FCE-SD and with higher amounts of added water into the gluten-free formulations. Kinetic data in modelling crumb firmness and ΔH values by linear regression analysis and the Avrami equation, respectively, revealed a slower staling rate for breads with sourdough, compared to control formulations; moreover, with increasing level of added water to the batter, the firming rate was reduced, while the amylopectin retrogradation was enhanced. Finally, in vitro enzymatic starch digestibility of the crumb was lower for staled breads stored for 5 days, compared to fresh products, while there was no pronounced effect by sourdough inclusion. Overall, the incorporation of FCE-SD into gluten-free bread formulations seems to be a promising alternative for improving quality and extending the shelf life of gluten-free baked products.

Stability of natural food colorants derived from onion leaf wastes.

Plant anthocyanins have widely been employed as natural food colorants. However, their instability restricts many of their applications in food industry. In this study, anthocyanins were extracted from onion outer scales, using aqueous solutions with or without added cyclodextrins (CDs). The results indicated that when cyclodextrins were included in the extraction medium, the anthocyanins were stable or even had improved and augmented color intensity upon storage or following thermal and UV-light treatments over a broad pH range (2.0-7.0). FT-IR and UV-Vis spectroscopy measurements confirmed the formation of inclusion complexes between CDs and anthocyanins and the presence of pyranosyl groups (pyranoanthocyanins) upon heating. Overall, the stability of onion anthocyanins under various environmental stresses, often encountered during food processing and storage, indicates that the natural color extract from onion outer scales can be of value as an interesting colorant alternative for food applications.

Mashes to Mashes, Crust to Crust. Presenting a novel microstructural marker for malting in the archaeological record.

The detection of direct archaeological remains of alcoholic beverages and their production is still a challenge to archaeological science, as most of the markers known up to now are either not durable or diagnostic enough to be used as secure proof. The current study addresses this question by experimental work reproducing the malting processes and subsequent charring of the resulting products under laboratory conditions in order to simulate their preservation (by charring) in archaeological contexts and to explore the preservation of microstructural alterations of the cereal grains. The experimentally germinated and charred grains showed clearly degraded (thinned) aleurone cell walls. The histological alterations of the cereal grains were observed and quantified using reflected light and scanning electron microscopy and supported using morphometric and statistical analyses. In order to verify the experimental observations of histological alterations, amorphous charred objects (ACO) containing cereal remains originating from five archaeological sites dating to the 4th millennium BCE were considered: two sites were archaeologically recognisable brewing installations from Predynastic Egypt, while the three broadly contemporary central European lakeshore settlements lack specific contexts for their cereal-based food remains. The aleurone cell wall thinning known from food technological research and observed in our own experimental material was indeed also recorded in the archaeological finds. The Egyptian materials derive from beer production with certainty, supported by ample contextual and artefactual data. The Neolithic lakeshore settlement finds currently represent the oldest traces of malting in central Europe, while a bowl-shaped bread-like object from Hornstaad-Hörnle possibly even points towards early beer production in central Europe. One major further implication of our study is that the cell wall breakdown in the grain's aleurone layer can be used as a general marker for malting processes with relevance to a wide range of charred archaeological finds of cereal products.

Simultaneous determination of phenolic acids and flavonoids in rice using solid-phase extraction and RP-HPLC with photodiode array detection.

An analytical method based on an optimized solid-phase extraction procedure and followed by high-performance liquid chromatography (HPLC) separation with diode array detection was developed and validated for the simultaneous determination of phenolic acids (gallic, protocatechuic, 4-hydroxy-benzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, sinapic, and cinnamic acids), flavanols (catechin and epicatechin), flavonols (myricetin, quercetin, kaempferol, quercetin-3-O-glucoside, hyperoside, and rutin), flavones (luteolin and apigenin) and flavanones (naringenin and hesperidin) in rice flour (Oryza sativa L.). Chromatographic separation was carried out on a PerfectSil Target ODS-3 (250 mm × 4.6 mm, 3 µm) column at temperature 25°C using a mobile phase, consisting of 0.5% (v/v) acetic acid in water, methanol, and acetonitrile at a flow rate 1 mL min(-1) , under gradient elution conditions. Application of optimum extraction conditions, elaborated on both Lichrolut C(18) and Oasis HLB cartridges, have led to extraction of phenolic acids and flavonoids from rice flour with mean recoveries 84.3-113.0%. The developed method was validated in terms of linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 5) and inter-day precision (n = 4) revealed relative standard deviation (RSD) <13%. The optimized method was successfully applied to the analysis of phenolic acids and flavonoids in pigmented (red and black rice) and non-pigmented rice (brown rice) samples.

Phase transitions, solubility, and crystallization kinetics of phytosterols and phytosterol-oil blends.

The thermal properties, solubility characteristics, and crystallization kinetics of four commercial phytosterol preparations (soy and wood sterols and stanols) and their blends with corn oil were examined. Differential scanning calorimetry (DSC) revealed narrow melting peaks between 138 and 145 degrees C for all phytosterol samples, reversible on rescan. Broader and less symmetrical melting transitions at lower temperatures with increasing oil content were observed for two samples of phytosterol-oil admixtures. The estimated, from the solubility law, deltaH values (34.7 and 70.7 mJ/mg for wood sterols and stanols, respectively), were similar to the DSC experimental data. Fatty acid esters of soy stanols differing in the chain length of the acyl groups (C2-C12) exhibited suppression of the melting point and increase of the fusion enthalpy with increasing chain length of the acyl group; the propionate ester exhibited the highest melting point (Tm: 151 degrees C) among all stanol-fatty acid esters. Solubility of phytosterols in corn oil was low (2-3% w/w at 25 degrees C) and increased slightly with a temperature rise. Plant sterols appeared more soluble than stanols with higher critical concentrations at saturation. The induction time for recrystallization of sterol-oil liquid blends, as determined by spectrophotometry, depended on the supersaturation ratio. The calculated interfacial free energies between crystalline sediments and oil were smaller for sterol samples (3.80 and 3.85 mJ/m2) than stanol mixtures (5.95 and 6.07 mJ/m2), in accord with the higher solubility of the sterol crystals in corn oil. The XRD patterns and light microscopy revealed some differences in the characteristics among the native and recrystallized in oil phytosterol preparations.

Production and characterization of pullulan from beet molasses using a nonpigmented strain of Aureobasidium pullulans in batch culture.

The production of pullulan from beet molasses by a pigment-free strain of Aztreobasidium pullulans on shake-flask culture was investigated. Combined pretreatment of molasses with sulfuric acid and activated carbon to remove potential fermentation inhibitors present in molasses resulted in a maximum pullulan concentration of 24 g/L, a biomass dry wt of 14 g/L, a pullulan yield of 52.5%, and a sugar utilization of 92% with optimum fermentation conditions (initial sugar concentration of 50 g/L and initial pH of 7.0). The addition of other nutrients as carbon and nitrogen supplements (olive oil, ammonium sulfate, yeast extract) did not further improve the production of the exopolysaccharides. Structural characterization of the isolated polysaccharides from the fermentation broths by 13C-nuclear magnetic resonance spectroscopy and pullulanase digestion combined with size-exclusion chromatography confirmed the identity of pullulan and the homogeneity (>93% dry basis) of the elaborated polysaccharides by the microorganism. Using multiangle laser light scattering and refractive index detectors in conjunction with high-performance size-exclusion chromatography molecular size distributions and estimates of the molecular weight (Mw = 2.1-4.1 x 10(5)), root mean square of the radius of gyration (R = 30-38 nm), and polydispersity index (Mw/Mn = 1.4-2.4) were obtained. The fermentation products of molasses pretreated with sulfuric acid and/or activated carbon were more homogeneous and free of contaminating proteins. In the concentration range of 2.8-10.0 (w/v), the solution's rheologic behavior of the isolated pullulans was almost Newtonian (within 1 and 1200 s(-1) at 20 degrees C); a slight shear thinning was observed at 10.0 (w/v) for the high molecular weight samples. Overall, beet molasses pretreated with sulfuric acid and activated carbon appears as an attractive fermentation medium for the production of pullulan by A. pullulans.