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关键词： grain modification   infrared radiation   mechanical properties   physicochemical properties   structural changes  

摘要： Infrared (IR) is a highly efficient and energy-saving technology known for uniform heating, less heating time, and high energy transfer rate to improve food product quality and safety. IR technology has many applications, including drying and dehydration, enzyme inactivation, pathogen inactivation, and other miscellaneous uses such as roasting, frying, and broiling. However, the effect of IR radiation on the overall behavior of the grain and its components has not received much attention. This review focuses on the changes in the properties of grain starch when exposed to IR radiation. The effects of alteration in structural characteristics of starch on the mechanical and functional properties and on starch digestibility patterns have been discussed. An attempt has been made to present the theoretical basis for the interaction of IR radiation with the grain and its components. IR radiations interact with food molecules to vibrate the bonds to cause stretching in them. The vibration energy causes rearrangement of starch molecules resulting in the modification of mechanical and functional properties as well as the starch digestibility pattern of the grain. These may bring about changes in the outlook of the grain and hence the IR technology may find application in the grain processing industry.

关键词： Wine   Ultrasounds   Frequency   Colour   Phenolic compounds  

摘要： This study presents the application of high-power ultrasounds (US) to crushed grapes using winery-scale equipment and studies, for the first time at this scale, how the frequency of the ultrasounds affects the extraction of phenolic compounds from grapes and the chromatic and physico-chemical characteristics of the finished wines, in an attempt to optimize the maceration process. The results showed how US modified the physical characteristics of the grape skin, facilitating phenolic extraction and improving the wine chromatic characteristics but only produced slight differences in the physico-chemical characteristics of the finished wines. The two different frequencies applied led to some differences in the wine phenolic composition, especially higher tannin extraction at 20 kHz whereas anthocyanin extraction was favoured at 28 kHz. Wines made with sonicated grapes and 72 h of skin maceration time were chromatically very similar to control wines with four more days of skin contact, indicating that this technological process may increase the working capacity of the winery by allowing a reduction of more than 50% in the maceration time.

关键词： extraction   pectin   pasting   response surface methodology   starch   sugar beet pulp   viscosity  

摘要： The objective of this study was to characterize the properties of pectin extracted from sugar beet pulp using subcritical water (SWE) as compared to conventional extraction (CE). The research involved advanced modeling using response surface methodology and optimization of operational parameters. The optimal conditions for maximum yield of pectin for SWE and CE methods were determined by the central composite design. The optimum conditions of CE were the temperature of 90 degrees C, time of 240 min, pH of 1, and pectin recovery yield of 20.8%. The optimal SWE conditions were liquid-to-solid (L/S) ratio of 30% (v/w) at temperature of 130 degrees C for 20 min, which resulted in a comparable yield of 20.7%. The effect of obtained pectins on viscoamylograph pasting and DSC thermal parameters of corn starch was evaluated. The contents of galacturonic acid, degree of methylation, acetylation, and ferulic acid content were higher in the pectin extracted by SWE, while the molecular weight was lower. Similar chemical groups were characterized by FTIR in both SWE and CE pectins. Color attributes of both pectins were similar. Solutions of pectins at lower concentrations displayed nearly Newtonian behavior. The addition of both pectins to corn starch decreased pasting and DSC gelatinization parameters, but increased Delta H. The results offered a promising scalable approach to convert the beet waste to pectin as a value-added product using SWE with improved pectin properties.

关键词： Chemical reactivity   Zeta potential   Piezoelectricity   Shearing   Intracrystalline deformation   Dislocation density   Quartz  

摘要： Chemical reactivity, grindability and zeta potential have been measured and correlated for three variably deformed quartz varieties from three different areas. Results show that there is a strong positive correlation between lattice imperfections and the measured physico-chemical and electrical properties of the three varieties. The highly deformed blue-grey quartz variety records the highest dissolution, grindability and surface electric charges compared to the less deformed milky and rose varieties. Microfabric study supported with XRD results show that the shear-related blue-grey variety exhibits a very strong intracrystalline deformation and high dislocation density indicative of low to intermediate grade conditions. The other two varieties, on the other hand, exhibit deformation features and lower dislocation densities pointing to a much lower grade. The higher chemical reactivity of the blue-grey quartz can be attributed in part to the morphological modifications the shearing creates within the quartz tetrahedra, and to the piezoelectric effect. Such modifications facilitate breaking the Si-O bonds, and lower the activation energy required to initiate the reaction between the silicon ions and the hydroxyl group. Piezoelectricity increases the electric potential across the crystal-liquid interface and hence setting the stage for the chemical reactions. The doubled value of zeta potential of the blue-grey quartz relative to the other two varieties opens the discussion of whether the inherited paleo-piezoelectricity of deformed quartz may enhance and play a significant role in the process of quartz dissolution or not.

关键词： Biological indices   Freshwater   Macroinvertebrates   Organic pollution   Seasonal effect  

摘要： Although the macroinvertebrates have been widely used as bio-indicator for river water quality assessment in developed countries, its application is new in Iran and data on the health status of the most ecologically important rivers in Iran is scarce. The present study aimed at monitoring and assessing the ecological quality of Aghlagan river, northwest of Iran, using integrated physicochemical-biological approaches. A total of 14,423 samplings were carried out from the headwater to downstream sites at four stations (S1, 2, 3, 4) by a Surber sampler (30 cm x 30 cm) from June 2018 to April 2019. The results obtained from macroinvertebrate biotic index revealed that the genera of Gammarus (Amphipoda) and Baetis (Ephemeroptera) were the most abundant in all seasons. The PAST software was applied to analyze the diversity indices (Shannon-Weiner diversity, Evenness, and Simpson indices). Based on the cluster analysis, S3 established the least similarity to other stations. The average frequency of each macroinvertebrate species was determined by one-factor analysis of similarities (ANOSIM). In accordance with canonical correspondence analysis (CCA), temperature and phosphate were found as the dominant factors effecting the macroinvertebrate assemblage and distribution. Moreover, the results obtained from the biological indices concluded very good quality of S4 by Helsinhoff and EPT indices and fair quality using BMWP index. The data on the macrobenthos assemblage and dynamics in the Aghlagan river across a hydraulic gradient provided useful information on water management efforts that assist us to find sustainable solutions for the enhanced quality of the river by balancing environmental and human values.

关键词： Legume protein   Amino acid   pH   Surface characteristics   Functional properties  

摘要： Mung bean (MPI), black bean (BPI), adzuki bean (API), rice bean (RPI), black kidney bean (BKPI), speckled kidney bean (SKPI), chickpea (CPI) and cowpea (CPPI) protein isolates were assessed for their surface (charge, hydrophobicity: H-0 and tension) and functional properties (solubility, water/oil holding capacity, WHC/OHC;foaming capacity/stability, FC/FS;emulsifying activity/stability indices, EAI/ESI and least gelling capacity, LGC) at pH 3.0, 5.0, 7.0 and 9.0, using soybean (SPI) and pea (PPI) protein isolates as controls. Physicochemical properties of these proteins, e.g., amino acid composition and colour (L*, a* & b*, WI: whiteness index), were also characterized. API, RPI, BKPI, SKPI and CCPI exhibited a better amino acid profile and protein digestibility than other isolates. BKPI (27.01) and SKPI (20.48) showed higher WI, while CPI (-21.92) was the lowest. For all isolates, H-0 was the highest at pH 3.0, followed by pH 7.0 and 9.0, while surface tension was the highest at pH 5.0, followed by pH 3.0. Compared to other proteins, BKPI and SKPI showed lower solubility, but were more effective to reduce surface tension. Most of the traditional legume proteins had similar EAI. CCPI showed better WHC/OHC and API, RPI, BKPI and SKPI displayed excellent FC/FS. Interestingly, LGCs of MPI (8%), BKPI (4%), SKPI (4%) and CCPI (6%) at pH 3.0 were significantly lower than other isolates (12%). Overall, BKPI and SKPI have good nutritional profiles and also possess excellent functionalities (except for WHC/OHC), which are very promising as new alternative legume proteins to SPI and PPI.

关键词： Climacteric fruit   colour   peel   plantain   respiration   ripening   soluble solids   starch  

摘要： The physicochemical and physiological attributes of three contrasting commercial varieties of Musaceae, Dominico Harton (plantain), Guineo (cooking banana) and Gros Michel (dessert banana), were evaluated and statistically analysed during post-harvest ripening. Quality attributes differed markedly among varieties, both in fresh fruits and during ripening. Variety (V) had a significant effect (P < 0.001) on all attributes except total soluble solids (TSS), carotenes and total chlorophyll. Storage time (ST) had a significant effect on all attributes except colour parameter b* and total carotenes. Starch levels decreased significantly (P < 0.001) during ripening, with nearly complete hydrolysis in Gros Michel, followed by Guineo and Dominico Harton. Discriminant analysis showed that central diameter, TSS of the pulp, colour parameter a* and total starch had the highest weight in the differentiation among varieties. These results point out which parameters may help improve current methods for monitoring ripening of bananas, in particular the commercially important varieties in this study.

关键词： crosslinking agents   digestibility   physicochemical properties   starch aerogels   vacuum drying  

摘要： In this study, sodium trimetaphosphate, adipic acid, sodium hexametaphosphate, and epichlorohydrin (EPI) are used to investigate the effect of the crosslinking reaction on the physicochemical properties and in vitro digestibility of corn starch aerogel (CSA). Gelatinization destroys the morphology of the corn starch granules, and the crosslinking reaction which is performed in the gelatinization stage considerably alters the structure of the gel. The aerogel prepared by adding 0.5% EPI shows the highest Brunauer-Emmett-Teller surface area among the crosslinked starch aerogels. Corn starch xerogels and aerogels all have porous network structures which may be related to the high amylose structure of corn starch. Gelatinization and crosslinking agents disrupt the short-range molecular order of corn starch, and the crosslinked CSA has relatively lower crystallinity and higher swelling power and solubility than the control. After crosslinking, rapidly digestible starch and resistant starch content of CSAs increase, while slowly digestible starch decreases slightly. Thus, the crosslinked CSA may be used for encapsulation with low digestibility.

关键词： Dioxime   XRD   HSA   MEP   NMR  

摘要： In this study, a novel trans-(1E,2E)-benzil-O,O-dimethylsulfonyl dioxime (BDMDO) monomer was prepared via a one-step dehydrochlorination reaction. BDMDO was characterized by H-1 and C-13 NMR, UV-Vis, and FT-IR spectroscopies, CHN elemental analysis, mass spectrometry, energy-dispersive X-ray spectroscopy, and TGA. According to the X-ray diffraction data, the BDMDO crystal structure was solved as a trans-isomer dioxime. The lattice structure was stabilized by two types of H-bonds and a sufficient number of interesting non-covalent supramolecular interactions such as the C-H center dot center dot center dot H-C bonds. Molecular electrostatic potential measurements and Hirschfeld surface analysis were performed to understand these interaction modes. The cis-trans isomerization in BDMDO as well as the structural, vibrational, NMR, highest occupied molecular orbital/lowest unoccupied molecular orbital bandgap, density of states, and electronic properties were computed by the density functional theory and subsequently compared with available experimental H-1 and C-13 NMR, UV-Vis, and FT-IR spectral data. The thermogravimetric/derivative thermogravimetric behavior of BDMDO was determined experimentally under an open-room atmosphere. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.

关键词： Dough-like model   Wheat gluten   Rice starch   Physicochemical properties  

摘要： In this study, wheat gluten/rice starch dough-like models were prepared by mixing wheat gluten with rice starch according to different ratios (0:100, 6:94, 8:92, 10:90, 12:88, and 14:86, w/w, based on the dry weight). The physicochemical and structural properties of gluten/rice starch dough-like models were studied. The addition of gluten resulted in higher water absorption, development time, stability time and lower degree of softening. The extensograph, texture profile analysis and rheology results showed that gluten significantly enhanced the viscoelasticity and extensibility of model dough. Moreover, the addition of gluten increased the swelling power and thermal stability, decreased the water solubility and thermodynamic enthalpy. The results of protein aggregation behavior indicated that the addition of gluten promoted the conversion of free sulfhydryl groups to disulfide bonds, which was beneficial to the formation of a uniform and compact protein network. Overall, the addition of gluten significantly improved the quality of gluten/rice starch dough-like model.