查看更多>>摘要：Encapsulated essential oils are being developed as natural antimicrobials and insecticides for use in sustainable agriculture applications. Although these plant-based pesticides are considered to be more environmentally friendly, they can have adverse effects on agricultural crops, thereby reducing yields. Our aim was therefore to establish the potential phytotoxicity of carvacrol nanoemulsions on a commercially important crop (spinach, Spinacia oleracea). Carvacrol oil-in-water nanoemulsions were fabricated by homogenizing 10 wt% oil phase (1:1 carvacrol and medium chain triglycerides) with 90% aqueous phase (1% quillaja saponin in 5 mM sodium citrate buffer, pH 3.5). Nanoemulsions were sprayed onto the spinach leaves by foliar exposure for three days and then the health status of the plants was assessed. At relatively low carvacrol concentrations (0.005-0.5%), the plants remained healthy, but at the highest concentration employed (5%) there was a significant reduction in the biomass and chlorophyll content of the spinach, as well as an increase in electrolyte leakage and malondialdehyde formation. We demonstrated that this strong phytotoxicity was due to the carvacrol oil, rather than due to other constituents in the nanoemulsions. Our results show that there is a critical threshold concentration for use of essential oil nanoemulsions as pesticides on crop plants.
查看更多>>摘要：Phycocyanin, the main pigment substance, is abundant in Nostoc sphaeroides. However, the thermal stability of phycocyanin is insufficient, so the processing and storage of Nostoc sphaeroides remain a critical problem. In this study, we have developed an innovative pasteurization technology: Radio frequency combined hot water pasteurization (RFCHWP) in order to improve the product quality of Nostoc sphaeroides. The results showed that RFCHWP technology exhibited good thermal uniformity and was effective in killing microorganisms in Nostoc sphaeroides. Compared to high-pressure steam sterilization (HPSS), heating by RFCHWP for less than 20 min had little effect on the color and texture of Nostoc sphaeroides samples. The ascorbic acid content of Nostoc sphaeroides decreased to 18.31 and 17.45 mg/100 g in the RFCHWP 30 min and HPSS samples, respectively. The phycocyanin content of Nostoc Sphaeroides in HPSS samples decreased by 32.89% compared with that in the RFCHWP samples. Phycocyanin was stable at a temperature of 50 degrees C and pH of 6-8. The results of this study showed that RFCHWP technology could be used as a bactericidal method for Nostoc sphaeroides with better product quality.
查看更多>>摘要：The possible mechanism was investigated for the antioxidant activity improvement on a novel peptide QMDDQ obtained from shrimp protein by PEF in this study. It was found that QMDDQ that treated under 40 kV/cm exhibited the best antioxidant activity. After PEF treatment, the primary structure of QMDDQ was not influenced, while the beta-sheet content was decreased and the random coil content was correspondingly increased in PEF-treated QMDDQ solution. The cross peak between C alpha H (4.53 ppm) on 4-Asp and C gamma H (1.78 ppm) on 5-Gln residue disappeared in PEF-treated peptide. After applying PEF treatment, the side chain of C-terminus residue Glutamine at was stretched to expose more active sites to combine with free radicals, thus enhancing the scavenging effect of radical. Hence, the antioxidant activity improvement of QMDDQ might be attributed to the targeted regulation of PEF treatment at C-terminal.
查看更多>>摘要：Sea buckthorn (Hippophae rhamnoides L.) pulp oil (SPO) is enriched in natural bioactive components with high pharmacological activities. However, the presence of polysaccharides affects oil quality. Herein, the effects of different polysaccharide-adsorption treatments on the bioactive components and the in vitro antioxidant activities of SPO were investigated. The results demonstrated that the microwave-assisted activated clay (MAE-ACL) adsorption was more effective than the ultrasound-assisted activated clay adsorption for removing polysaccharides. Although the bioactive component levels and antioxidant activities of the SPO were reduced during the adsorption, the squalene content showed no significant difference. By performing principal component and correlation analyses that further evaluated the connection between the bioactive components and the free radical scavenging activities of SPO, MAE-ACL was determined to be the more suitable polysaccharide-adsorption treatment.
查看更多>>摘要：The present investigation was aimed to fabricate oil in water curcumin loaded nanoemulsions (Cur-NE) stabilized using Tween 20 employing ultrasonication for the encapsulation of curcumin. Effect of various process variables such as surfactant and oil concentration and sonication time intervals on the stability of curcumin nanoemulsions were studied by characterizing droplet size, polydisperity index (PDI), zeta-potential (zeta), Encapsulation Efficiency (EE), DPPH-Radicals Scavenging Activity (RSA) and turbidity of formulated nanoemulsions. Cur-NE designed using oil 5 mL/100 mL, 1.5 % surfactant and treated for 20 min of ultrasound fetched better results for droplet size (138.9 nm), PDI (0.187), zeta-potential (-20.7 mV), EE (93.6 %) and RSA (67.56 %). Physical stability of Cur-NE was investigated by exposing them to variable thermal stress conditions. Stable emulsions obtained were characterized for their morphology and in vitro release kinetics under simulated gastrointestinal conditions. The morphology results were also verified the successful designing of ultrasound assisted curcumin loaded nanoemulsion. Results of in vitro release studies suggested that the optimized Cur-NE were resistant to pepsin digestion with less than 10 % release of curcumin whereas incubation under intestinal conditions led to approximately 23 % release of curcumin indicating its slow release and increased bioavailability. Therefore, outcomes of the study demonstrated the important implications in designing of encapsulation systems for various bioactive compounds for their effective and controlled delivery in various food products.
查看更多>>摘要：Bruising is the most common type of damage occurring during all stages of postharvest handling, and it is difficult to detect by human inspection because of minor changes in appearance. Hyperspectral imaging technology was used to detect bruised tomatoes caused by falling damage, and the influence of fruit size, drop height and detection time point on hyperspectral characteristics was studied. The results showed that the spectra of bruised tomatoes were lower than those of healthy tomatoes, and the features corresponding to the spectra round 810 nm played a significant role. The fruit size had the greatest impact on the spectrum of damaged tissue due to falling damage, while, the detection time point had the smallest effect. Scanning electron microscopy (SEM) observations showed that the drop test under various influencing factors had an obvious effect on the internal cell structure of tomatoes, and the most serious damage to the cell structure occurred in the group with 1 m falling height of large tomatoes. Partial least squares discriminant analysis models were developed to classify bruised tomatoes with an overall classification accuracy of 90.93%. The SEM and simulated data confirmed the experimental results, indicating that hyperspectral technology can classify tomato bruise damage.
查看更多>>摘要：The effect of superheated steam treatment on the physicochemical properties of wheat flour and quality characteristics of cake were investigated. Superheated steam treatment significantly increased the swelling power, viscosities and gelatinization temperature, but reduced the gelatinization enthalpy (p < 0.05), compared with native wheat flour. However, the dough made from the treated flour was harder to form. Moreover, superheated steam treatment significantly increased the value of falling number. Cake quality was affected by the changes in the physicochemical properties of wheat flour. Results showed that superheated steam treatment significantly decreased the hardness of cake from 1465 g (native flour) to 377 g (150 degrees C, 1 min), and increased the specific volume of cake from 3.12 mL/g (native flour) to 3.9 mL/g (150 degrees C, 1 min). The present study suggests that superheated steam treatment has great potential as a flour modification technology for cake quality improvement.
查看更多>>摘要：In this study, we aimed to formulate low glycemic index gluten-free cookies from high amylose rice flour by modifying baking conditions and ingredient composition. Baking temperature, baking time, and concentration of carboxymethyl cellulose were varied between 170 and 190 degrees C, 12-25 min, and 0.2-1%, respectively, using central composite rotatable design. Among the physical quality attributes, spread ratio and hardness of cookies increased predominantly with the increase in baking temperature. Resistant starch content and overall acceptability of cookies increased prominently, whereas predicted glycemic index and glycemic load decreased with the increase in the concentration of carboxymethyl cellulose. Design expert predicted baking temperature of 185 degrees C, baking time of 22 min, and 0.8% concentration of carboxymethyl cellulose as desirable conditions for the development of gluten-free low-glycemic index cookies from rice flour. Dietary fiber content of developed cookies was recorded as 4.66%. In-vitro starch digestibility results confirmed that resistant starch increased from 2.85% in rice flour to 7.20% in cookies, whereas predicted glycemic index and glycemic load decreased from 50.12 to 30.07 in rice flour to 44.60 to 17.51 in cookies, respectively. Overall acceptability of cookies was recorded as 8.90 on a 9-point hedonic scale.
查看更多>>摘要：The type of oil used and the introduction of bioactive compounds could strongly influence the microstructure and physicochemical properties of Pickering emulsions, which have yet to be fully understood. Herein, oil-in-water (O/W) Pickering emulsions were stabilized by autofluorescent gelatin nanoparticles with either corn oil or medium chain triglyceride (MCT) oil as references for commonly studied edible oils. The microstructure of the emulsions with changes in nanoparticle concentration, oil fraction (Phi), and oil type was investigated with confocal laser scanning microscopy (CLSM). An increase in nanoparticle concentration resulted in an increased thickness of the adsorption layers and number of droplets. Increasing Phi helped to form compact gel-like emulsions and improve the oxidation stability of the emulsions. The high oil-water interfacial tension and surface-active long-chain fatty acids of corn oil caused sparse packing droplet interfaces. Hence, corn oil emulsions were generally less stable than MCT oil emulsions, which was further demonstrated through studies of water holding capacity (WHC), long-term storage stability, and rheology. Furthermore, the incorporation of beta-carotene had negative effects on the formation and stability of the emulsions, especially for corn oil emulsions. The findings in this work may have important implications for exploiting Pickering emulsion formulations in real food products.
查看更多>>摘要：The antioxidant capacities of cherry (Prunus pseudocerasus) flavonoids, astragalin cyanidin-3-O-glucoside, cynaroside, quercetin, rutin, and vitexin were evaluated using in vitro assays and in vivo model. With in vitro assays, cyanidin-3-O-glucoside, cynaroside, or rutin showed higher activity in scavenging DPPH (2,2-diphenyl-1-picrylhydrazyl), superoxide, and hydroxyl free radicals and reducing power than astragalin, quercetin or vitexin. In in vivo model, high dose treatments of cyanidin-3-O-glucoside and rutin increased SOD (superoxide dismutase) activities in mouse serum, liver, kidney and heart. These treated mice also had higher GSH-Px (glutathione peroxidase) activity in serum and liver. Astragalin and vitexin treatments did not increase either SOD or GSH-Px activity in mice. All the flavonoids significantly reduced MDA (malondialdehyde) level in mouse serum, liver, kidney and heart. Especially, the MDA level of serum or liver in mice treated with high dose of cyanidin-3-Oglucoside, quercetin, or rutin was lower than vitamin C treatment. Based on chemical structures of the flavonoids, the flavonoid with two hydroxyl groups on phenyl ring B had higher antioxidant capacity than the flavonoid only having one hydroxyl group on the ring. Therefore, the antioxidant capacity of flavonoid may be correlated with the number of hydroxyl groups on ring B in its structure.
NSTL
Elsevier