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关键词： antioxidant activity   aqueous enzymatic microwave assisted extraction   chemical compositions   macadamia nut oil   physicochemical properties  

摘要： This study presents the green and effective aqueous enzymatic process assisted microwave extraction (AEME) to preparate macadamia nut oil (MNO). The conditions of the extraction process are optimized (extraction temperature 50 degrees C, extraction time 64 min, enzyme concentration 1.60% (w/w), and irradiation power 450 W). An oil yield of 58.09 +/- 0.63% is achieved under these optimal conditions. The scanning electron micrograph (SEM) analysis of nuts before and after extraction illustrates that AEME promotes the emancipation of oil stored within the organelles. Gas chromatography-flame ionization detector (GC-FID) analysis reveals the fatty acid compositions of MNOs obtained by AEME and the Soxhlet extraction (SE) are similar and mainly dominated by monounsaturated fatty acids beneficial to human health which is higher in MNO than in any other known food. Moreover, gas chromatography-mass spectrometry (GC-MS) analysis reveals higher amounts of more odoriferous oxygenated terpenes is present in the MNO extracted by AEME in comparison with SE. The physicochemical properties of AEME oil are more excellent than those of SE oil. Moreover, AEME oil exhibits superior antioxidant capacities. In conclusion, green AEME gives relatively satisfactory yield and better retains the fragrance and functionality of MNO. Practical Applications: The present study provides a green extraction method and valuable data for the process design as well as industrial scale-up applications. In addition, compared to the nonsustainable and environmentally nonfriendly traditional method, AEME preserves the initial composition of the flavor substances and enhances the extraction of healthy beneficial compounds in MNO. Therefore, AEME oil can be used to develop functional edible oils or even in medicinal, cosmetic, and pharmaceutical preparations.

关键词： functional properties   Heat and relative humidity treatment   mung bean   physicochemical characteristics   gamma-aminobutyric acid  

摘要： A novel approach to heat and relative humidity (HRH, 65-75 degrees C, 98% RH) treatment was used to enhance gamma-aminobutyric acid (GABA) of mung bean with a low moisture (12-20%) within several hours (4-6 h). Meanwhile, the changes in micronutrients, antioxidant activities and physicochemical properties were also evaluated. Results showed that the GABA content was significantly accumulated, increasing from 1.73 to 109.78 mg 100 g(-1) dry weight (DW) under the conditions of 16.72% moisture, 68.97 degrees C, 98% RH for 5.34 h. Meanwhile, the amino acids, including aromatic (tyrosine and phenylalanine), sulphur-containing (methionine and cystine) and branched-chain amino acids (leucine, isoleucine and valine), were significantly increased (P < 0.05). Although HRH treatment decreased the total anthocyanin content of mung bean, the total phenolic, vitexin and isovitexin contents, and antioxidant activities were significantly increased (P < 0.05). Furthermore, HRH treatment caused the wrinkled structure of mung bean coat, increased the paste viscosity of mung bean flour and decreased the time of complete gelatinisation of starch in mung bean by one third during cooking. These results suggested that HRH treatment could effectively elevate the above functional components, especially GABA, improve the antioxidant activities, pasting and cooking properties of mung bean.

关键词： Kiwifruit   pulsed vacuum impregnation   quality   trehalose  

摘要： Pulsed vacuum impregnated trehalose to improve the physicochemical quality of frozen-thawed kiwifruit was investigated. Kiwifruits were treated by pulsed vacuum impregnation (PVI) with 10%, 20% and 30% trehalose, then frozen and stored at -20 degrees C. The results showed that PVI with 30% trehalose treatment exhibited minimum drip loss (11.21%), maximum ascorbic acid content (0.93 g kg(-1)) and firmness (12.3 N), and retained the flavour and taste as well as improved water distribution for frozen-thawed kiwifruit as compared with other treatments: control, PVI with 10% and 20% of trehalose. Therefore, the results illustrated that pulsed vacuum impregnated trehalose could be used as an effective method to improve the quality of frozen-thawed kiwifruit.

关键词： grain positions   nitrogen application   starch properties  

摘要： Nitrogen is an important factor that influences the yield and quality of wheat grain. However, little is known about its effect on the different positions of the grain in spikelets. Compared with the control group, nitrogen application increased the weight, starch content, and protein content of grains in each position considerably. In particular, the protein content in high grain positions of Yangmai 13 (YM 13) under nitrogen treatment are similar to those positions in Yannong 19 (YN 19) under normal levels. Nitrogen application substantially increased the volume proportion of small starch granules and the average degree of polymerization (DP) but reduced the apparent amylose content (AAC), and the breakdown values (BV) of the first grain (G1) and the second grain (G2) in YN19. Nitrogen application considerably increased AAC, the volume proportion of small starch granules, and the ordered structure of starch surface of G1 and AAC, BV, and DP of G2 in YM13. These results demonstrated that a medium nitrogen level is conducive to increase the agronomic traits in high-position grains and a better pasting properties of starch in low-position grains.

关键词： CO2-rich groundwater   Physicochemical stratification   CO2 exsolution   Iron oxy-hydroxides precipitation   Automated monitoring  

摘要： Unusual episodic fluctuations of electrical conductivity (EC) were observed twice a year in a national groundwater monitoring network well in South Korea where EC was automatically monitored at a depth of 20 m below ground level (bgl). To address the causes of the observed EC fluctuations, this study examined the depth profile of wellbore water in the 70-meter-deep monitoring well screened between 50 and 70 m bgl and cased down to 50 m bgl. The results of well logging, borehole video recording, and hydrochemical analysis of wellbore water indicated that the CO2-rich groundwater entering through the screened zones below 50 m bgl was physicochemically stratified into three layers with distinct EC that were separated by two transition zones in the well: a bottom layer (70-43 m bgl) with an EC of -3900 mu S/cm, intermediate layer (35-24 m bgl) of -1800 mu S/cm, and top layer (16-3 m bgl) of -300 mu S/cm. The first transition zone at depths of 43-35 m bgl was attributed to CO2 exsolution in the open system and the subsequent physicochemical changes of wellbore water, while the second transition zone at depths of 24-16 m bgl was formed by the precipitation of hydrous ferric oxides with consequent sorption of remaining ions due to a sudden change toward the oxidizing environment. The monitoring probe installed at a depth of 20 m bgl was found to be located within the upper transition zone, which caused EC peaks when the well was purged at a depth of 25 m bgl for well maintenance twice a year. This study shows that automated groundwater monitoring systems may misguide one about the groundwater quality if an unexpected physicochemical variation (such as stratification) occurs in a monitoring well. Therefore, the presence of interface zones caused by abrupt changes in EC must be carefully considered when an automated monitoring well is designed. The screened zone is a suitable location for installing an automated monitoring probe to measure the representative water quality (i

关键词： antioxidant activity   Chinese dried noodles   flaxseed flour   microcosmic   sensory evaluation   texture analysis  

摘要： Chinese dried noodles (CHDNs) were fortified with unhulled flaxseed flour (UHFF) and hulled flaxseed flour (HFF), and textures, antioxidant activities, sensory properties and microstructure were investigated. The optimal levels of UHFF and HFF added to CHDNs were 5% and 10%, respectively. Compared with HFF, UHFF addition enhanced the in vitro antioxidant activities but significantly decreased the colour of CHDNs. The addition of UHFF and HFF increased the cooking loss and decreased the hardness, firmness force, tensile strength and fracture distance ratio of cooked CHDNs in a dose-dependent manner. The addition of levels of 5% UHFF, as well 5% and 10% HFF increased the flaxseed aroma of CHDNs. Both UHFF and HFF decreased the gaps in the internal structure of CHDNs. UHFF remarkably increased the roughness of CHDNs compared with HFF. In summary, UHFF and HFF have the potential to improve the overall quality of CHDNs without compromising the eating quality.

关键词： Humic acids (HA)   Biowastes   Antioxidant properties   Hybrid nanoparticles   Aging   Supramolecular reorganization  

摘要： Humic acids (HA) are considered a promising and inexpensive source for novel multifunctional materials for a huge range of applications. However, aggregation and degradation phenomena in aqueous environment prevent from their full exploitation. A valid strategy to address these issues relies on combining HA moieties at the molecular scale with an inorganic nanostructured component, leading to more stable hybrid nanomaterials with tunable functionalities. Indeed, chemical composition of HA can determine their interactions with the inorganic constituent in the hybrid nanoparticles and consequently affect their overall physico-chemical properties, including their stability and functional properties in aqueous environment. As a fundamental contribution to HA materials-based technology, this study aims at unveiling this aspect. To this purpose, SiO2 nanoparticles have been chosen as a model platform and three different HAs extracted from composted biomasses, manure (HA_Man), artichoke residues (HA_Art) and coffee grounds (HA_Cof), were employed to synthetize hybrid HA-SiO2 nanoparticles through in-situ sol-gel synthesis. Prepared samples were submitted to aging in water to assess their stability. Furthermore, antioxidant properties and physico-chemical properties of both as prepared and aged samples in aqueous environment were assessed through Scanning Electron Microscopy (SEM), N2 physisorption, Simulta-neous Thermogravimetric (TGA) and Differential Scanning Calorimetric (DSC) Analysis, Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR) spectroscopies. The experimental results highlighted that hybrid HA-SiO2 nanostructures acted as dynamic systems which exhibit structural supramolecular reorganization during aging in aqueous environment with marked effects on physico-chemical and functional properties, including improved antioxidant activity. Obtained results enlighten a unique aspect of interactions between HA an

关键词： Green banana flour   Rejected banana   Physico-chemical   Functional properties   Filmogenic suspension   Rheological properties  

摘要： Physico-chemical, functional properties, and filmogenic characteristics were determined in pulp (P) and whole (W) banana flours (BF), pretreated or not (preT and unT, respectively) with sodium metabisulfite, obtained from cultivars of Ecuadorian Musaceae: Musa acuminata AAA. The proximal composition revealed a high content of fat, protein, ash, and fiber in whole banana flours, while the total starch and amylose content was greater in pulp flours. The starch granules of both pulp and whole green banana flours presented an elongated and lenticular sizes and shapes, which could be related to the amount and variations in amylose and amylopectin structure in the raw materials. Pretreatment with metabilsulfite favors the increase in L* and b* parameters, while a* is reduced;likewise, the presence of the peel tends to darken the untreated flours. Water absorption, solubility and swelling capacity rose above 70 degrees C, matching the gelatinization temperature observed by DSC (74-78 degrees C). The temperature of gelatinization was higher for the pretreated whole banana flour, noticeably, the highest enthalpy Delta H-gel (32.23 Jg(-1)) corresponded to the untreated whole banana flour. All banana flours had the ability to form filmogenic suspensions that showed a similar pseudoplastic behavior regardless of the flour composition, except for the pretreated pulp flour, which showed less shear thinning. The viscosity recovery capacity with the decrease in temperature was almost total in the untreated samples, while in the treated samples was lower (similar to 20%). The higher amount of amylopectin favored the viscoelastic properties in the filmogenic suspension, while the lower content of this compound diminished these properties. For the aforementioned, green banana flours are an ingredient of interest and their ability to form filmogenic solutions can be a good alternative for its subsequent industrial application.

关键词： flat-die extrusion   physicochemical properties   starch-based nanocomposites   starch nano   micro particles  

摘要： Nanotechnology has been crucial in the development of environmentally friendly and naturally based materials for food packaging. In this work, an inexpensive and scalable way to develop amylopectin-enriched nanocomposites with nano/micro particles of starch is investigated. Cassava starch nanocomposites with rich-amylopectin starch nano/micro particles (S-AP) are prepared by flat-die extrusion. S-AP, obtained by applying shear stresses to an aqueous solution of native cassava starch using grinding, consists of (10.8 +/- 0.9)% of nanofiller (< 200 nm) and (88 +/- 1)% of micro-size particles (2-10 mu m). After processing, great compatibility between S-AP and the matrix is achieved. Nanocomposites with 15 wt.% of S-AP show increases in Young's modulus (73%), tensile stress (30%), and tensile toughness (63%), and a decrease in water vapor permeability (34%) compared to the films without S-AP (TPS). The use of 30 wt.% of S-AP leads to a slight increase in crystallinity without significant changes in the overall properties, as a consequence of the combination of the effects produced by the presence of nanofiller and the enrichment of the matrix in amylopectin. This investigation provides a methodology for developing amylopectin-enriched starch nanocomposites with high compatibility between the nanofiller and the matrix as an attractive alternative for conventional starch-based packaging.

关键词： Freeze-drying   lutein   microcapsule   physicochemical properties   spray-drying  

摘要： In this study, the lutein was microencapsulated by complex coacervation with gelatin and OSA starch as vehicles, and the physicochemical and in vitro release properties of the microcapsules were evaluated followed by the spray drying or freeze-drying method. Preliminary assays of coacervation indicated that a higher encapsulation efficiency was obtained at the gelatin/OSA starch volume ratio of 5:4 and the core/wall material volume ratio of 1:8 (v/v) followed by the spray-drying method. The lutein-gelatin-OSA microcapsules had a higher solubility, antioxidant activity, thermostability, relative humidity stability and sustained in vitro release compared to the free lutein. Fourier transform infrared data indicated that the encapsulated lutein interacted with gelatin and OSA starch was mainly through hydrogen bonding, hydrophobic and electrostatic interactions. The freeze-dried microcapsule was observed with a more regular shape, smaller particle size in morphology and confirmed with better thermal stability from the differential scanning calorimetry results while the spray-dried microcapsules obtained a higher cumulative release rate of lutein and higher antioxidant activity. The results of this study are expected to contribute to the design and commercial application of gelatin-OSA starch complex-based delivery systems for hydrophobic nutraceuticals with desired physicochemical properties and digestive performance.