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关键词： Expression optimization   Escherichia coli   Molecular dynamic simulation   Rational design   Reteplase   Response surface methodology  

摘要： Structural engineering of the recombinant thrombolytic drug, Reteplase, and its cost-effective production are important goals in the pharmaceutical industry. In this study, a single-point mutant of the protein was rationally designed and evaluated in terms of physicochemical characteristics, enzymatic activity, as well as large-scale production settings. An accurate homology model of Reteplase was used as the input to appropriate tools to identify the aggregation-prone sites, while considering the structural stability. Selected variants underwent extensive molecular dynamic simulations (total 540 ns) to assess their solvation profile and their thermal stability. The Reteplase-fibrin interaction was investigated by docking. The best variant was expressed in E. coli, and Box-Behnken design was used through response surface methodology to optimize its expression conditions. M72R mutant demonstrated appropriate stability, enhanced enzymatic activity (p < 0.05), and strengthened binding to fibrin, compared to the wild type. The optimal conditions for the variant's production in a bioreactor was shown to be 37 oC, induction with 0.5 mM IPTG, for 2 h of incubation. Under these conditions, the final amount of the produced enzyme was increased by about 23 mg/L compared to the wild type, with an increase in the enzymatic activity by about 2 IU/mL. This study thus offered a new Reteplase variant with nearly all favorable properties, except solubility. The impact of temperature and incubation time on its large-scale production were underlined as well.

关键词： Cold storage  

摘要： The objective of the current study was to develop innovative quinoa-coated chicken nuggets by using quinoa flour instead of wheat flour and evaluate the impact of this substitution on the shelf life of the product and its nutritional and sensorial stability. The evaluation of the product has been done through physiochemical and microbiological analysis every three days of the storage period compared with negative control (NC) and positive control (BHT) through 24 days of cold storage (4 +/- 1 degrees C). During storage, the quinoa flour-coated chicken nuggets showed the best ability for delay of lipid oxidation with a lowest TBARS value of 1.07 mg MDA/kg compared to negative control (NC) (2.39 mg MDA/kg) and positive control (BHT) (2.00 mg MDA/kg). The same trend was observed in protein oxidation, where the quinoa flour was able to retard the protein oxidation better than negative and positive control (BHT) where it showed a carbonyl content of 6.44, 5.39, and 4.20 nmol carbonyl content/mg protein, respectively. The quinoa-coated chicken nuggets showed the lowest microbial load (5.8 x 10(3) cfu/g) compared to negative and positive controls (1.8 x 105 and 3.8 x 104 cfu/g) at 24 days of cold storage. These findings could be emphasized such that the utilization of quinoa flour in the coating of chicken nuggets is more effective in retarding lipid and protein oxidation, furthermore preventing microbial contamination during cold storage. All these findings might be playing a crucial role in the extending of the shelf life of the product in addition to giving the product a pleasant taste and flavor to consumers.

关键词： Molecules  

摘要： Artemisinin is used to treat multi-drug resistant strains of malaria and is also in the early stages of development as an anti-cancer drug. However, the usage of artemisinin is limited due to its low aqueous solubility. Herein a large scale cocrystal screening of artemisinin was conducted using both computational and experimental approaches, leading to a new 2 : 1 artemisinin and acetylenedicarboxylic acid (ART(2)-ACA) cocrystal. ART(2)-ACA crystallises in the P2(1)2(1)2(1) space group of the orthorhombic system with cell parameters a = 10.5089 angstrom, b = 24.083 angstrom, and c = 6.4952 angstrom. The asymmetric unit of the cocrystal contains two ART molecules and a single ACA molecule, assembled into discrete trimeric units held together by two supramolecular heterosynthons. It was shown that ART(2)-ACA cocrystals have higher solubility and a faster dissolution rate compared to the parent drug artemisinin.

关键词： Bovine serum protein  

摘要： Bovine serum albumin (BSA) and BSA-glucose conjugates (GBSAI and GBSAII) with different extent of glycation were complexed with curcumin (CUR). The formation mechanism of BSA/GBSA-CUR complexes and the effect of glycation on their physicochemical properties were investigated. Fluorescence quenching and FTIR analysis indicated that the BSA/GBSA-CUR nanocomplexes were formed mainly by hydrophobic interactions. XRD analysis demonstrated that CUR was present in an amorphous state in the nanocomplexes. BSA with a greater extent of glycation (BSA < GBSAI

关键词： Peanut oil   Resveratrol   Ultrasound-magnetic stirring-assisted dissolu-tion   Solubility and physicochemical  

摘要： The solubility and physicochemical properties of resveratrol in peanut oil were systematically studied following ultrasonic and magnetic stirring-assisted dissolution. The highest resveratrol solubility in peanut oil observed was 95.91%. The optimal dissolution process was determined to be the addition of 183.00 mg/kg resveratrol, a magnetic temperature of 40.00celcius, and a magnetic duration of 3.50 h, which yielded a resveratrol content of 175.51 mg/kg oil. Under this standardized process, the oil composition remained unchanged. Resveratrol promoted the conversion of saturated triglycerides into unsaturated triglycerides, increased the linolenic acid content, and did not facilitate the formation of trans fatty acids. In addition, resveratrol preserved the light color, decreased the peroxide and acid values by 30%, prolonged the shelf life by more than 2 folds, and improved the thermal stability. In this sense, peanut oil with resveratrol can serve as anti-isomerism and antioxidant additive.

关键词： Flaxseed   Microwave exposure   Oil bodies   Physicochemical stability   Interface remodeling  

摘要： This study aimed to investigate the influences of microwave (MV) exposure to flaxseed on the physicochemical stability of oil bodies (OBs) focused on the interface remodeling. The results showed that the intracellular OBs subjected to absolute rupture and then partial dispersion by protein bodies visualized by TEM following MV exposure (1-5 min;700 W). After aqueous extraction, native flax OBs manifested excellent spherical particles with completely intact surface and wide particle size distribution (0.5-3.0 mu m) examined by cryo-SEM. Upon 1-5 min of MV exposure, the defective interface integrity and beaded morphology were successively observed for flax OBs, accompanied by the impaired physical stability and rheological behavior due to the newly assembled phospholipid/protein interface. Notably, the profitable migration of phenolic compounds effectively suppressed the lipid peroxidation and protein carbonylation in flax OBs. Thus, MV exposure (1-5 min;700 W) was unfavorable for improving the physical stability of flax OBs.

关键词： Nigella seed oil   Roasting   Fatty acids   Pigments   MRPs   Oxidative stability  

摘要： In this study, oils extracted from nigella seeds (NS) subjected to microwave roasting at 180, 360, 540 and 720 W for 5 and 10 min were evaluated for quality and stability characteristics. The impact of microwave powers on oil yield, pigment content, Maillard reaction products (MRPs), radical scavenging activity (RSA), color, viscosity, total phenolic content (TPC), oxidative stability index (OSI) and fatty acid composition (FAC) of oil was studied. TPC, RSA, OSI, MRPs, viscosity, chlorophyll and carotenoid contents were higher in oil of NS heated at 720 W for 10 min while maximum oil yield and low acid value was observed for NS heated at 540 W for 10 min. FAC was slightly influenced by microwave roasting and FTIR spectra exhibited a minor difference in intensities of peaks at 3009, 2925, 2854, 1745 and 1161 cm-1. The results of the study indicated that microwave roasting improves NS oil quality characteristics.

关键词： Principal component analysis  

摘要： This research was conducted to evaluate consumer preferences of seven extra virgin olive oils (EVOOs) from foreign and Tunisian cultivars. Two studies were carried out. The first is a comparative physicochemical characterization of the VOOs tasted by the consumers. The second is a consumer survey where each consumer tasted each VOO six times. Using simple linear regressions, we have performed a new method that gives a pairwise comparison between the oils. It revealed that Coratina and Chetoui cultivars were the most preferred revealing by the high concentration of polyphenols with 468 and 525 ppm, respectively, and Arbequina was the less preferred with 182 ppm. We have then performed a principal component analysis on the data composed by the physicochemical parameters that highly discriminate between cultivars. The latter showed important differences between the most and the less preferred oils and that oxidative stability, palmitic, palmitoleic, oleic, and linoleic fatty acids, triacylglycerol, beta-carotene, and polyphenols seem to be the principal-choice drivers for consumers.

关键词： Cold plasma   Functional characteristics   Bioactive compounds   Antinutrients   Enzymes   Textural properties   Sensory properties  

摘要： Cold plasma processing is a technique that uses electricity and reactive carrier gases, such as oxygen, nitrogen, or helium, to inactivate enzymes, destroy microorganisms, preserve food, and maintain quality without employing chemical antimicrobial agents. The review collates the latest information on the interaction mechanism and impact of non-thermal plasma, as an emerging processing technology, on selected physical properties, low-molecular-weight functional components, and bioactive properties of food. Significant changes observed in the physicochemical and functional properties. For example, changes in pH, total soluble solids, water and oil absorption capacities, sensory properties such as color, aroma, and texture, bioactive components (e.g., polyphenols, flavonoids, and antioxidants), and food enzymes, antinutrients, and allergens were elaborated in the present manuscript. It was highlighted that the plasma reactive species result in both constructive and antagonistic outcomes on specific food components, and the associated mechanism was different in each case. However, the design's versatility, characteristic non-thermal nature, better economic standards, and safer environmental factors offer matchless benefits for cold plasma over conventional processing methods. Even so, a thorough insight on the impact of cold plasma on functional and bioactive food constituents is still a subject of imminent research and is imperative for its broad recognition as a modern non-conventional processing technique.

关键词： Polyvinyl alcohol films   Carboxy methyl cellulose   Amino acids   Antibacterial activity   Food packaging  

摘要： The intention of this study was to prepare polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) films and to improve their physicochemical properties by cross-linked with amino acids. Thus, the bio-composite films/membranes of PVA/CMC were an amalgamation with L- Histidine as the crosslinker via solution casting scheme. The effect of the L-Histidine addition on blend films was explored by various physio-chemical characterisation techniques. The contact angle assessment of the as-prepared film have remained increased (47.31, 50.42, and 58.09) by the addition of L-Histidine content. The antibacterial activity was tried against certain food pathogenic bacteria. To the extent of the clear zone width of theE. coliandB. cereusbacteria were included per filmstrips and the values of which remained constantly higher than the width of assumed films. Largely, the L-Histidine cross-linked PVA/CMC film happens to be a suitable material for an antibacterial agent and food-packaging applications.