查看更多>>摘要：There is a growing interest in the value utilization of fish by-products. In this study, an advisable method of Takifugu obscurus by-products hydrolysates (F0) developed into flavor seasoning was investigated. The F0 were separated into two peptide fractions, >3000 Da (F1) and 300-3000 Da (F2), and performed Maillard reaction, then flavor characteristics of the Maillard reaction products were comprehensively analyzed. The results showed that the Maillard reaction largely improved flavor profiles of the hydrolysates i.e., enhancing umami taste, volatile aroma, and overall acceptance, while reducing bitterness and fishy smell. Compared with F0 and F1, F2 as the suitable resource of flavor precursors, had the optimal flavor attributes after Maillard reaction. This paper provides a new idea of comprehensive utilization of by-products of pufferfish and guides the preparation of Maillard peptide-based seasoning from fish by-products.
查看更多>>摘要：This study explored the effect of direct current magnetic field (DCMF) of 3.8 mT combined with temperatures (4 +/- 1 degrees C, low temperature, LT; 22 +/- 1 degrees C, room temperature, RT) on the properties of low-salt myofibrillar protein (MP) gel. DCMF with LT treatment could improve the water holding capacity (WHC) of MP gel from 22.76% to 24.24%, but had no effect on the gel treated with RT. This could be explained that DCMF incubation promoted the cross-linking between protein molecules by disulfide bonds in heating process, which contributed to the network structure of gel, thus improving the WHC. Furthermore, the microstructure of MP gel showed that DCMF incubation at LT could alter the network structure of gel, verified by Raman spectroscopic analysis that a conversion of 8-turn to random coil in the secondary structure of MP gel, which supported this explanation.
Neoh, Galex K. S.Tao, KeyuDieters, Mark J.Fox, Glen P....
8页
查看更多>>摘要：Wheats affected by late-maturity alpha-amylase (LMA) contain abnormal amounts of alpha-amylase with a high isoelectric point (pI), causing their flours to have low falling number (FN), a standard industry test. LMA-affected wheats are often rejected at grain receival points, as low FN is perceived as sign of poor quality. To improve LMA detection and increase screening throughput, an LMA-ELISA has been developed. The present study evaluated the analytical performance of LMA-ELISA and confirmed the correlation between LMA content and enzymatic activity. The LMA-ELISA test demonstrated good discrimination and high precision for intra- and inter-assay measurements. However, results were not reproducible when using three different LMA-ELISA batches acquired in two consecutive years, indicating that LMA-ELISA suffered from batch-to-batch variation. Consistent with previous studies, LMA-ELISA was highly correlated to total alpha-amylase activity (R = 0.95). LMA-affected flours also had enzymatic activity similar to enzyme-supplemented flours that have been shown to produce some end-products such as bread and noodles that are of satisfactory quality. These results highlight the need to address LMA-ELISA batch-to-batch variation.
查看更多>>摘要：Physical instability and oxidation were two of the most evident problems existing in food emulsions. In this research, a facile approach of solidifying the oil phase by stearic acid was adopted to overcome the above problems simultaneously, emphasising the effect of the oleogelation extent. Polarizing microscope, rheological analysis, and X-ray diffraction (XRD) were used to characterize the oleogelation of the oil phase, and droplet size, microscopic observation and peroxide value analysis were applied to evaluate the emulsion stability. Results showed that with moderate solidification of the oil phase (0.8%-1.0% w/v stearic acid in oil phase), the emulsions exhibited excellent physical stability under the stress of centrifugal force, high salt, and long-term storage. Moreover, the oxidative stability of the emulsions was improved simultaneously, that the increasing of peroxide value was slowed significantly. Excessive solidification (e. g. 3% w/v stearic acid) of the oil phase would weaken these advantages or even bring about opposite results, due to the destruction of the emulsion droplets by the excessive crystallization. Our results suggested that moderate solidification of oil phase would be a feasible and effective approach to improve the stability of o/w emulsions, which would be significant for the industrial-scaled production.
Crespo, LauraGaglio, RaimondoMartinez, Fernando G.Martin, Gustavo Moreno...
12页
查看更多>>摘要：Adequate fruit consumption helps to prevent several chronic age-related diseases. Selenium (Se) is an elemental micronutrient with antioxidant capacity. In general, fruits and Se ingest by humans are below the recommended daily intake value. Fresh fruits are highly susceptible to deterioration during storage. Fermentation can improve the storage period, sensory profile, and bioactive compound content of foods; moreover, some lactic acid bacteria can accumulate organic Se intracellularly. In this work, microbial growth and Se accumulation by Levilactobacillus brevis CRL2051 and Fructobacillus tropaeoli CRL2034 in tropical fruit juices were evaluated. The strains could grow 1-2 log cfu/mL, alone or combined, in mango, passion fruit, and mango/passion fruit juices, although they could not completely eliminate native microorganisms in unpasteurised juices. In pasteurised trials, both strains consumed fruit carbohydrates producing lactic acid, in addition to acetic acid, and mannitol by F. tropaeoli. Both strains accumulated Se intracellularly in the fruit juices, especially (123.0 mu g/L) in the passion fruit juice fermented by the mixed culture. Finally, the Fructobacillus strain increased 3.42 times the phenolic compound concentration in the mango/passion fruit juice with added Se after 24 h. The assayed LAB strains could be used for preparing functional fermented fruit beverages bio-enriched in Se.
查看更多>>摘要：A practical, efficient, and rapid method for quantifying 19 pyrethroids in tea and orange samples was developed in this research. After extracting pyrethroids through QuEChERS procedure, liquid chromatography electrospray ionization quadrupole-time-of-flight mass spectrometry (LC-ESI-Q-ToF/MS) was applied to elucidate the fragmentation pathways and product ions of 19 pyrethroids. The identified ions were exclusive targets to quantify 19 pyrethroids by triple quadrupole mass spectrometry (LC-ESI-QqQ-MS/MS). Confirmation and quantification transition ions of 19 pyrethroids were fragmented from either ammonium adducts or hydrogenated molecules. Analytical performances, including method limits of detection (0.07-0.29 mu g/kg), linearities (0.9914-0.9993), relative standard deviations (1.6-5.0%), and recoveries (89.8-109.5%), met the requirements of Chinese National Standards. Matrix-matched standard curves were employed for the calibration of some pyrethroids with medium matrix effect in tea and orange samples. The detection and quantification of 19 pyrethroids from local tea and orange samples revealed that no pyrethroid was tested out from 209 peeled orange samples. Although 11 pyrethroids were detected positive from 161 out of 262 tea samples with the means of concentration ranging from 15 to 169 mu g/kg, their levels were still below maximum residue limits.
查看更多>>摘要：Various treatments applied during dairy processing strikingly affect milk proteins, the major structural determinants, thus causing modifications in some techno-functional and biological properties of the final dairy product. Cheeses, with a variety of types, are mostly consumed processed dairy foods worldwide. The purpose of this study was to investigate the effect of heating, culture/enzyme activity and other treatments on the composition and molecular structure of cow milk proteins during the processing of different cheeses through electrophoresis, chromatography and spectroscopy. Electrophoretic patterns of the samples successfully indicated differences in protein content through process steps and in the final products. Curdling after pasteurization at 85 degrees C revealed many newborn peptides not detected in raw cow milk and other dairy samples. High and low similarities in peptide profiles of cheeses to that of raw cow milk indicated high-temperature pasteurizationinduced unfolding facilitated extensive proteolysis subsequently. Significant conformational changes including loss of alpha-helices and exposure of beta-strands observed in the secondary structure of proteins especially through curdling might offer alterations of reactive/functional groups. In total, pasteurization, curdling, salting, and ripening treatments remarkably altered the content and structure of cow milk proteins through unfolding, denaturation and aggregation, strongly suggesting modified functionality when milk was processed to cheese.
查看更多>>摘要：Red wine grape color and quality decrease substantially at the late stages of ripening in warm climates because of anthocyanin degradation; however, the underlying mechanism remains unclear. We analyzed the anthocyanin metabolite and transcriptome profiles of Yan73 grape berries from two vintages using HPLC-ESI-MS/MS and RNA-sequencing technologies. The results showed that anthocyanins in Yan73 grape skin and flesh were significantly degraded at the late stages of ripening in both vintages. Moreover, non-methylated anthocyanins were degraded at a higher rate than the methylated anthocyanins. The protocatechuic acid (i.e., possible anthocyanin degradation product) concentration increased significantly in Yan73 skin and flesh at the late stages of ripening. However, the expression of anthocyanin biosynthesis-related structural genes and MYBA1 was upregulated in Yan73 skin and flesh at the late stages of ripening, indicating an increase in the anthocyanin synthesis capacity. Enzyme activity and qRT-PCR assays revealed that peroxidase and polyphenol oxidase activities and the VvPrx31 expression level increased in Yan73 skin and flesh at the late stages of ripening, suggesting they may function in the anthocyanin degradation. The beta-glucosidase activity was higher only in Yan73 grape flesh at the late stages of ripening. These findings clarify the pre-harvest anthocyanin degradation in grape berries.
da Silva, Denise FelixBettera, LucaIpsen, RichardHougaard, Anni Bygvraa...
4页
查看更多>>摘要：Egg is well known to have great emulsifying properties in emulsion systems such as mayonnaise. However, egg yolk is a food allergen leading to the need for alternatives. The emulsification properties of cheese powder in mayonnaise were studied in comparison with egg yolk powder. Four percent of cheese powders were added during mayonnaise production and the resultant rheological properties, stability, and microstructure were evaluated. The cheese powders were based either on Cheddar or Camembert and powders from the latter were made with and without use of emulsifying salt. Use of cheese powder enabled development of a gel-like structure in the mayonnaise. Mayonnaise made using Cheddar cheese powder showed the highest degree of similarity to egg yolk powder in terms of rheological properties and exhibited a high consistency index (a K-value of 33.6 Pa s(n)) and higher stiffness (G'-2.2 kPa). On the other hand, samples with Camembert cheese powder showed decreased consistency index (a K-value of 4.1-7.3 Pa s(n)) and lower G'-1 kPa even if emulsifying salts were added (G'similar to 1.6 kPa). All cheese powders ensured good fat emulsification but were less able to bind water.
查看更多>>摘要：This study aims to prepare myofibrillar microgel particles (MMP) by microfluidics employed as a novel foodgrade Pickering stabilizer, and explore the effect of particle size and wettability on emulsifying capacity. The emulsifying capacity and stability of MMPs were analyzed by characteristics of particles, emulsion and interface adsorption. MMP with the z-average diameter of 150-250 nm owned better amphipathic property, and its threephase contact angle was about 88.5 degrees. The MMP emulsions exhibited a smaller droplet size, lower degree of flocculation and better emulsion stability than myofibrillar emulsion. The MMPs quickly diffused to the oil-water interface and the rearrangement degree of MMP was lower (by 3-4 fold), which explained the mechanism of its better emulsifying capacity and stability from the perspective of interface absorption. These results suggested that MMP presented better emulsifying and interfacial properties, thus imparting a higher emulsifying capacity and stability for the emulsions. Simultaneously, the wettability of MMP could play a decisive role in emulsifying capacity and emulsion stability. However, the particle size of MMP had little influence on emulsifying capacity. This study can provide a theoretical basis for the scientific preparation and screening of microgel Pickering emulsifiers.
NSTL
Elsevier