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The use of microwave and pulsed electric field (PEF) processing to optimize polyphenol extraction from defatted hemp seed cake in mixed solvent of methanol, acetone and water (MAW, 7:7:6 v/v/v) was investigated using the Box-Behnken response surface method. A variables combination for microwave processing of time, microwave power and liquid to solid (L:S) ratio and for PEF (ethanol concentration, time, frequency and voltage) were used in the investigation. Following microwave or PEF treatments, the polyphenols were extracted from the samples under ultrasound with fixed variables (200 W of ultrasonic power, water bath of 70 °C and 20 min of extraction time). The measured responses were total phenolics (TP), total flavonoids (TF), DPPH˙ scavenging activity and ferric reducing/antioxidant power (FRAP). The optimum variables combination for microwave processing (5 min treatment time, L:S ratio of 6, 700 W power and volume 30 mL) and PEF-assisted extraction (voltage (30 V), frequency (30 Hz), ethanol concentration (10 %) and time (10 s)) resulted in maximum yields in all measured responses. The results suggest that microwave processing and PEF can be integrated in processing defatted hemp seed cake to enhance polyphenol extraction and maximize the yield.

To improve the drying rate and energy efficiency of Angelica sinensis, and maximally maintain quality after harvest, this study investigated the effects of temperature, ultrasonic power and ultrasonic frequency on the water migration, physicochemical quality and microstructure of Angelica sinensis by ultrasonic-assisted vacuum far-infrared drying. The results showed that compared with the samples without ultrasound, the material drying time after the ultrasonic-assisted far-infrared drying treatment was reduced by 18.2%~50.0%. Six different mathematical models were investigated and the Midilli model was the best-fitted model for all samples (R2 was 0.9956~0.9992, RMSE was 0.86 × 10–4~1.20 × 10–4). After ultrasonic treatment, the color, rehydration ratio, natural active ingredients, total phenolic, total flavonoid, polysaccharides, antioxidant capacity in samples were significantly increased (P < 0.05), and the shrinkage ratio of dried products was reduced significantly (P < 0.05). In addition, it greatly improved the internal structures of the dried products, and a uniform and regular honeycomb-like pore structure appeared inside the material after ultrasound. Therefore, ultrasonic-assisted vacuum far-infrared drying could improve drying rate and final product quality of Angelica sinensis.

The aim of this study was to determine the effects of microwave pretreatment on physicochemical characteristics of carob flour and rice starch–based nanofibers produced by electrospinning. The effects of microwave heating on production of nanofibers by electrospinning have not been studied before. Another aim of the study was to fabricate and characterize nanofibers by using different carob flour concentrations (3%, 5% w/v) and rice starch (0.5% w/v). Films were characterized by scanning electron microscopy, water vapor permeability, X-ray diffraction, mechanical test, differential scanning calorimeter, and Fourier transform infrared spectrophotometer. Homogenous and bead-free fibers were obtained when microwave heating was used. Nanofibers originated from microwave-heated solution presented better characteristics in terms of water vapor permeability and mechanical properties as compared with conventionally heated ones. Microwave-heated solution had higher viscosity and available amino group amount as compared with conventionally heated solution. This study showed that microwave heating can be considered as a promising pretreatment method for electrospinning rather than conventional heating to be used in food packaging area.

In the food industry, browning and colour alteration are usually the main problems to solve in red juices. In an attempt to ease complications due to pomegranate juice processing, the combination of thermal treatment, storage at selected temperature and blending of juices was assessed as a novel and combined solution. A pure monovarietal juice, a combination of two widely distinct varietal juices (75 % Mollar de Elche + 25 % Wonderful) and a blend of pomegranate juice plus lemon (75 % + 25 %, respectively) were compared after pasteurization at two different heat treatments (high temperature–short time (HTST) and low temperature–long time (LTLT)). The effect of processing on the bioactive composition and colour parameters was monitored during juice shelf-life at two storage conditions (room and refrigeration temperatures). The reaction kinetics of main phytochemicals and a factorial analysis were also performed in order to achieve comprehensive data on the evolution of juice quality during storage. Results displayed how blending can protect the desirable properties of pomegranate juices better than pure monovarietal juices. Likewise, a high specificity between thermal treatment and kind of juice was found for each considered parameter. HTST exhibited a higher protective role than LTLT for blends of varietal pomegranate juices, whilst LTLT seemed to protect mixtures with lemon much better than HTST. Moreover, the concomitant degradation of anthocyanins and vitamin C and their role in colour variations were exposed. Overall, the array of outcomes might provide a satisfactory solution of colour alteration in pomegranate juices as well as red fruits in general.

Legislation and concerns about health effects of trans and saturated fatty acids have led to elimination or reduction of them in foods formulation. One of the alternatives for structuring food with healthy ingredients is using food-grade biopolymers such as proteins or polysaccharides to formulate hydrogels. The aim of the present work was to study the relationship among formulation, gelation kinetics, structure, and rheological properties of sodium caseinate (NaCas)/sunflower oil hydrogels prepared from nanoemulsions. NaCas was used as stabilizer in concentrations of 1, 2, 3, or 4 wt.%. Sucrose was also added in 2, 4, 6, or 8 wt.% to the 4-wt.% nanoemulsion. Gelation kinetics was studied by two methods: oscillatory rheometry and Turbiscan. Although gelation time values were significantly different between methods, tendencies were similar: values decreased with increasing protein and sucrose contents. However, the most influential factor on gelation time was the ratio glucono-delta-lactone (GDL)/NaCas. Structure was analyzed by confocal laser scanning microscopy and synchrotron X-ray microtomography. Low-protein content hydrogels (1 or 2 wt.%) had an inhomogeneous structure containing nano- and conventional-size droplets while the 4-wt.% hydrogel kept the initial structural characteristics: homogeneity in dispersed phase distribution and non-aggregated nanodroplets. Sucrose improved structure in terms of homogeneity. Analyses of X-ray microtomoghraphy data showed that while the porosity diminished, the wall width increased with increasing protein and sucrose contents. The hydrogel formulated with 4 wt.% NaCas and 8 wt.% sucrose showed a structure with nanodroplets evenly distributed and the highest G′∞ values of all hydrogels.

In this study, a kind of Pickering emulsion with a desirable interface architecture and sesame paste flavor was prepared using zein, apple pectin (AP), and sesame oil. Zein-AP composite nanoparticles (ZAPs) were first assembled via an anti-solvent procedure and electrostatic adsorption for stabilizing sesame-oil-in-water Pickering emulsions (ZASPEs). ZASPEs (volume fraction of oil φ = 0.7) exhibited excellent plasticity and viscoelasticity (indicated by low-field NMR spectroscopy and rheology). Confocal laser scanning microscopy (CLSM), demonstrated the anchoring of ZAPs at the oil–water interface, while cryo-SEM confirmed the three-dimensional microstructural network formed inside the emulsion. Compared to a commercial sesame paste, diluted ZASPEs (φ = 0.35) exhibited similar rheological and sensory properties, while ZASPEs (φ = 0.7) and diluted ZASPEs possessed greater smoothness and spreadability. Accordingly, the current ZASPEs as new additions to the existing Pickering emulsions not only function as bioactive carriers but also impart desirable flavor in food applications.