查看更多>>摘要：The present research was to investigate the influences of pretreatments on the structural and physicochemical properties of proteins isolated from canola seeds (CSP) after oil extraction by supercritical CO2 fluid. The results showed that the CSPs pretreated with microwave treatment (MV-CSP) and ultrasound treatment (UL-CSP) significantly differed in terms of molecular weight distribution, amino acid composition, and the primary conformation of CSP. The crystalline properties and secondary structural conformation as well as average particle sizes of CSPs were not significantly influenced by pretreatments, but the morphological characteristics were remarkably changed. The physicochemical properties including solubility, water/oil holding capacity, emulsifying capacity and stability, as well as foaming capacity and stability were substantially altered by the pretreatments. The MV-CSP and UL-CSP possessed better physicochemical characteristics. Therefore, microwaveand ultrasound-pretreatments could serve as potential technologies to improve the physicochemical properties of canola seeds proteins. Moreover, different oil extraction methods greatly influenced the quality and functional properties of isolated CSPs. The supercritical CO2 (SC-CO2) process protected intact functional properties and enhanced the overall quality of the isolated CSPs compared to solvent extraction.
查看更多>>摘要：The aim of the study was to investigate the use of dietary wheat fibre (short and long fibre) and soy protein (concentrate and isolate) as carriers of potassium iodide (KI) and potassium iodate (KIO3) by determining changes in the iodine content under different storage conditions. The iodised carriers and table salt were stored in closed glass jars at the following temperatures and relative humidity: 25 degrees C/60%, 25 degrees C/90% and 40 degrees C/90%, and two layers: 2 cm and 10 cm.
查看更多>>摘要：The drying kinetics and quality properties of mulberries dried in hot-air were investigated at four temperatures (40, 50, 60, and 70 degrees C). A convenient tool, Low-field nuclear magnetic resonance (LF-NMR) and MRI techniques were used to study the water state and distribution during the drying process. The results showed that the water reached equilibrium with drying times of 83, 38, 29, and 17 h at drying temperatures of 40, 50, 60, and 70 degrees C, respectively. The Page model fantastically described the drying process of mulberries. The transverse relaxation time (T-2) curves showed that T-2 times of free water decreased to the equilibrium points corresponded exactly with the first stage of drying kinetic curves. MRI showed that water diffused from the internal to the external during drying. Optimum color, texture, microstructure and higher total anthocyanin content were found in mulberries dried at 50 degrees C. Notably, higher correlations between LF-NMR parameters and quality properties were found by partial least squares regression (PLSR), with the analysis results being credible.
查看更多>>摘要：Navel oranges (Citrus sinensis. Newhall) are widely planted in several major production areas in southern China, with the Gannan region being the most distinctive. In this study, UPLC-Q-TOF/MS was used to discriminate the geographical origin of navel oranges harvested from distinct production areas in China. Results showed that the unsupervised analysis (PCA) explained 30.8% of the total variance, whereas supervised analysis (OPLS-DA) with cross-validated (RY)-Y-2 and Q(2) values of 0.991 and 0.914, respectively, can obtain potential metabolites with better discrimination between Gannan and Non-Gannan regions. Forty-two potential differential metabolites with VIP >1.0 and P < 0.05 (T-test) were selected and identified. Three of these metabolites (narirutin 4'-glucoside, sinapic acid and farnesyl acetone) with AUC > 0.7 and P < 0.05 in logistic-regression analysis were included in the establishment of the receiver operating characteristic combined diagnostic analysis. Further, 16 metabolites were used to generate a suitable classification model for the targeted classification of the samples from different areas. These results provide guidance for geographical discrimination of navel oranges, and its application may be extended to improve planting conditions of navel oranges.
Park, Su JeongKim, Dong HyunKang, Hye JeeShin, Minhye...
7页
查看更多>>摘要：gamma-Aminobutyric acid (GABA) is an amino acid not present in proteins. GABA participates in a variety of physiological functions and has received significant attention in the medical and food industries. In this study, GABA production was investigated using Lactobacillus plantarum. We designed a synthetic medium consisting of the simplest medium components such as yeast extract (nitrogen source), glucose (carbon source), and monosodium L-glutamate (MSG; substrate for GABA) and optimized their proportions to efficiently produce GABA. As a result, 19.8 g/L GABA was obtained under an optimal synthetic medium composition of 100 g/L yeast extract, 10 g/L glucose, and 2.25% MSG, which is the highest among previous studies using L. plantarum. Interestingly, 159.7% of theoretical maximum yield based on initial MSG content was obtained since yeast extract acts as a secondary source of substrate. By proper optimization with the simplest medium using L. plantarum, it can produce a high titer of GABA as well as might help various functional foods containing GABA to develop.
查看更多>>摘要：The changes in water distribution and structural properties of myofibrillar protein (MP) in marinated pork belly induced by the addition of different concentrations (0.00, 0.25, 0.50, 1.00, and 2.00 g/kg) of tannic acid (TA) were examined. Transverse relaxation time and population measurements revealed that the 0.50 g/kg TA treatment improved water retention in the marinated pork belly samples. There was an initial increase and a subsequent decrease in the free amino group, alpha-helix, and beta-sheet content, as well as fluorescence intensity, as TA concentration increased. Meanwhile, the opposite trend was observed in the ditymsine content and surface hydrophobicity of the marinated pork belly samples. The free amino group, alpha-helix content and fluorescence intensity of 0.50 g/kg TA samples were increased by 23.1%, 10.3% and 28.6%, and ditymsine content and surface hydrophobicity were decreased by 2.6% and 2.9% compared with the samples without TA. Therefore, the effect of TA on water distribution and protein structural properties in marinated pork belly is related to its concentration. Addition of 0.50 g/kg TA can significantly delay the loss of water and improve protein structure stability of MP in pork belly during marinating.
查看更多>>摘要：The aim of the present study was to assess labeling accuracy and detect food fraud practices as well as to detect DNA sequences originating from GMOs in meat products commercially available in Athens, Greece. A total of 139 different samples from 23 producers were included in the study. DNA was extracted from the samples and subjected to PCR aiming for species-specific sequences for the detection of pork, beef, chicken, turkey, donkey and horse meat as well as the screening elements P-35S, T-nos, CP4-epsps, pat and bar, for the detection of DNA originating from GMOs. In total, 72 products, i.e. 52% of the samples, were mislabeled and correct labeling was verified for the products originating from only 7 out of the 23 companies. This mislabeling may be attributed to lack of good manufacturing practices that resulted in cross-contamination in 31 cases, definite substitution in 3 cases and suspected substitutions in 37 cases. Donkey and horse meat as well as DNA sequences originating from GMOs were not detected.
查看更多>>摘要：Bioactive oligosaccharides are important compounds for development of functional foods and ingredients. In this study, lactose derivative hetero-oligosaccharides were produced by acceptor reaction of glucansucrase E81 with whey. The synthesis of oligosaccharides was monitored by Thin Layer Chromatography (TLC) analysis followed by (1 ) and C-13 Nuclear Magnetic Resonance (NMR) spectroscopy analysis which demonstrated the glycosylation of lactose with alpha-(1 -> 2), alpha-(1 -> 3) and alpha-(1 -> 4) linkages. Liquid chromatography-mass spectrometry (LC-MS) analysis demonstrated the formation of DP 7 oligosaccharides from whey. The synthesized oligosaccharides were not digested under in vitro human gastric juice and alpha-amylase conditions. The prebiotic effect of lactose derivative hetem-oligosaccharides was tested and no growth in pathogenic strains was observed whereas certain probiotic strains utilised lactose derivative hetem-oligosaccharides as Carbon source and their growth was promoted. These findings can be important to reveal the potential of glucansucrases to produce functional oligosaccharides from different sources including waste materials.
查看更多>>摘要：Polygalacturonase is an important enzyme related to quality of fruits and vegetables that it is usually inactivated by heat. This research aimed to determine the structural changes associated with the thermal inactivation of thermolabile polygalactumnase (PG2), which were studied using molecular modeling and by measuring the free sulfhydryl and intrinsic fluorescence changes. The inactivation followed a first-order kinetics during 5 min of heating (50-80 degrees C). The in silico investigation at single molecule level revealed that the temperature increase up to 80 degrees C affected the overall conformation of the catalytic site. When compared to the native enzyme, important changes of the surface available to the solvent of two catalytic amino acids, Asp(202) and His(223), were noticed at 70 degrees C (-27.7% and +108.6%, respectively). Further temperature increase up to 80 degrees C disrupted the hydrogen bonds connecting the amino acids within the catalytic site (His(223)-Asp(201)) and between the catalytic and binding site (Asp(201)-Lys(258)). Intrinsic fluorescence changes revealed perturbation of the tertiary structure and were in line with an all-or-none process. The evolution of free sulfhydryl indicated reaction of the Cys(109) residue. The most important event in the thermal inactivation of PG2 is likely the narrowing of the access to the catalytic site.
查看更多>>摘要：Whole hempseed (WHS) flour was incorporated (0-40 g/100 g) in whole wheat (WW) flour to prepare composite flour (CF) blends. In the absence of additives, the dough structure weakened, and water absorption capacity and dough stability were significantly reduced in direct relation with the increasing content of WHS flour. At 40 g/100 g supplementation, the hardness index of WHS chapati decreased by 60% compared to WW chapati. The addition of vital gluten (VG) enabled the formation of a continuous structure between protein and starch molecules thus stabilizing the dough by 1.4 folds. The protein and fibre content increased from 12.39 +/- 0.19 and 11.78 +/- 0.62 in WW chapati to 18.55 +/- 0.02 and 18.29 +/- 0.52 in 30 g/100 g WHS chapati, respectively. Further, an increase of 5% in in-vitro protein digestibility was observed in the case of 30 g/100 g WHS chapati. The supplementation of chapati with WHS flour raised the total PUFA content from 58.1 +/- 0.5 in WW chapati to 73.5 +/- 0.23 in WHS chapati and, the essential fatty acids ratio also improved by 4.6 folds. The underutilized seeds of hemp can be used to enhance the nutritional value of staple foods such as chapati in terms of plant-based protein, omega-3, and omega-6 fatty acids.
NSTL
Elsevier