查看更多>>摘要：Cod cut offs, as a by-product of cod processing, is often discarded and wasted. A cod protein gel (CP-gel) was produced from homogenized steamed cod cut offs to turn the otherwise "waste" into treasure. The effects of homogenizing conditions on the physicochemical properties of the CP-gel were investigated by assessing the gel strength, water holding capacity (WHC), rheological properties and microstructure, combined with the visual appearance. After homogenization at 80 MPa with 15 passes, the particle size was reduced to 4 mu m and resulted in a gel strength of 0.63 N. The WHC of cod protein gel increased by 41% as compared to the un-homogenized sample. The secondary structures of the microfibrillar proteins changed as evidenced by the increased alpha-helix content by 3% via homogenization. The reduced particle size allowed particle-particle interactions and promoted protein cross-linking via both hydrophobic interaction and hydrogen bond formation. A relatively smooth and honeycombed network structure was formed with improved gel quality and physical properties. CP-gel provides a potential to utilize cod cut offs to produce value-added products.
查看更多>>摘要：The nitrite that normally exists in fermented foods is a threat to public health. Nitrite degradation by lactic acid bacteria (LAB) has the advantages of safety and low cost. This study investigated the effect of Lactobacillus plantarum DMDL 9010 (LP9010) on growth phenotype under nitrite stress from the perspective of whole genome sequencing. The results showed that LP9010 has certain tolerance to nitrite. However, high nitrite concentration (5-12.5 mmol/L) inhibited the growth and acid production. Nitrite could not only affect the morphology of LP9010 cells with longer phenotype, shrink and dent on the surface (even crack), but also decreased cell surface hydrophobicity. Correspondingly, 19 genes encoding stress proteins have been found in the genome. In addition, genes related to osmotic regulation proteins and peptidoglycans synthesis were found in the genome of LP9010, which may affect the cell wall structure under nitrite stress. Low pH lactic acid could degrade nitrite, whereas nitrite was hardly degraded when pH > 4. In addition, we found the putative nitrite reductase gene in LP9010, the nitrite ion bound to the Cd1NiR (pgl) active site by forming two hydrogen bonds with the residues PRO87 and PRO88. This study could provide theoretical reference to reduce nitrite in food products.
Schwartz, Isabela do MonteAmaral, Priscilla F. F.Ferreira, Tatiana FelixFinotelli, Priscilla, V...
7页
查看更多>>摘要：Sourdough production can be considered one of the oldest biotechnology processes because it has been used in bread manufacture for thousands of years. Today, sourdough baking involves the improvement of flavor, texture, and microbiological shelf-life of bread. Fermentations are based on the unique symbiosis of certain lactic acid bacteria and yeasts. Sourdough appreciation has grown worldwide, but mainly in artisanal bakeries due to the difficulties and costs of maintaining a live microbial culture (sourdough starter) in industries. To reduce the need for sourdough starter maintenance, researchers have evaluated drying techniques, such as freeze-drying and spray-drying, to preserve high fermentation capacity and cell viability after reconstitution. The main idea of the present review is to identify how drying processes can help to obtain a shelf-stable sourdough starter whose microorganisms are in an inactive state but could be reactivated at fermentation time. As drying technologies can strongly influence microbial viability, the flavor, and the shelf life of the final product, distinct specifications are required in each technique. Freeze-drying, for example, requires the presence of a cryoprotectant to prevent cell damage during the freezing moments. In spray-drying, the inlet and outlet temperatures are critical parameters that affect microorganism survival. The conditions and solvents used for dried powder rehydration are an important step to recover dried cells of the sourdough starter, as well as the starter activation before fermentation. Freeze-drying and spray-drying show great potential to increase the widespread use of sourdough on an industrial scale.
查看更多>>摘要：Foodborne illnesses are major public health concerns affecting many people across the globe. Post-harvest wastage due to microbial contamination is a major cause for food loss in the fresh produce sector. These losses account for more than 25% even before produce reaches the consumer and contribute to economic loss and food insecurity. The benefits of eating fresh produce outweigh the disadvantages of production and waste because it occupies an important position in the food pyramid for its nutritional content. Many non-thermal and thermal techniques are used to reduce pathogenic microorganisms that contaminate fresh produce at the preharvest and post-harvest stages. While thermal techniques are efficient in achieving sufficient microbial stability, they significantly reduce nutritional content and freshness of the produce. At present, consumers prefer minimally processed foods with less nutritional loss and extended shelf-life. Researchers have studied several non-thermal techniques to meet the consumer preferences and some of them are commercialized. The application of these techniques depends on the food matrices and purpose. This review discusses mechanism of action, application and safety of non-thermal techniques such as pulsed light technology, high-pressure processing (HPP), pulsed electric fields (PEF) and irradiation used for the treatment of fresh produce and their advantages and disadvantages.
查看更多>>摘要：There is an increasing demand by consumers for low-alcohol beverages with enhanced flavors and potential health benefits. This study evaluated the effects of cultivars and fermentation with Saccharomyces cerevisiae or Torulaspora delbrueckii on the chemical composition, antioxidant capacity and sensory properties of low-alcohol strawberry beverages. Compared to juice, fermentation increased the contents of ethyl esters but reduced the contents of anthocyanins (-60%) and organic acids (-50%). The cultivar was the most important factor affecting the physicochemical characteristics and antioxidant capacity of fermented beverages. Among the cultivars, the beverages from the 'Honeoye' presented the highest sourness, opacity, redness and color density, total anthocyanins and phenolics, and antioxidant capacity but the lowest pungent aroma and ethanol content. Without added sugar, there was no significant difference in ethanol content between fermented beverages produced by S. cerevisiae and T. delbrueckii. Compared to S. cerevisiae, fermentation involving T. delbrueckii resulted in higher contents of anthocyanins and enhanced the color and flavor of the beverages. The results indicated that strawberry cultivars should be considered to produce fermented beverages with consistent physicochemical and sensory properties, and T. delbrueckii can be an alternative yeast for producing low-alcohol beverages from strawberries.
Catania, AnibalLerno, LarrySari, SantiagoFanzone, Martin...
10页
查看更多>>摘要：The presented study evaluated anthocyanins, anthocyanin-derived pigments and chromatic characteristics of six micro-oxygenation treatments resulting from applying oxygen at different times and rates. Oxygen was applied before malolactic fermentation (MLF) at a rate of zero or 20 mg O2/L/month and after MLF at rates of zero, 4.5 or 9 mg O2/L/month. LC-MS analysis after 6 months of bottle aging indicated that the formation of anthocyaninderived compounds was related to the acetaldehyde (ACH) levels. When observing an increase in the level of ACH, formation of compounds was enhanced in which ACH was involved as B-type vitisins. Otherwise, where ACH was not involved, compounds as A-type vitisins, pinotins and direct adducts, were formed. Although the wine was filtered after MLF, only a marginal increase in the ACH concentration was observed during post-MLF MOX. This increase occurred only in wines that had previously received pre-MLF MOX. When MOX was applied at both moments and highest rates, wines produced a higher yellow color component (b*) and hue (hab) than the rest of the wines. These CIELab parameters were highly correlated with flavanyl-pyranoanthocyanins. These results suggest that in order to stabilize wine color, it is recommended to apply MOX before and after MLF.
查看更多>>摘要：The effect of different freezing temperature (-20 degrees C, -40 degrees C and -80 degrees C) on the properties (mainly molecular structure and functional properties) of gelatin extracted by microwave-freezing-thawing coupling method were compared systematically. The results showed that as the decrease of freezing temperature (-20 degrees C similar to -40 degrees C), the yield and gel strength increased from 11.80% to 14.55% and 753.00 g-825.67 g respectively due to the easier dissolution of subunit components induced by destruction of fish skin structure, while the lower freezing temperature (-80 degrees C) resulted in decrease of gel strength (734.00 g) due to the easier degradation of subunit components induced by excessive destruction of fish skin structure during the microwave extraction process. The FTIR results confirmed the destruction of the triple helix structure of gelatin at freezing temperature -80 degrees C, thus decreasing the thermal stability and exposing more hydrophilic amino acids with a reduced surface hydrophobicity (281.72-200.21). At freezing temperature (-40 degrees C), the gelatin showed the best foaming property and emulsifying properties, attributing to the lower interface tension induced by higher hydrophobicity. This study would provide guiding significance for the industrial production and the regulation of the physicochemical and functional properties of green gelatin.
查看更多>>摘要：In this study, the antimicrobial efficiency of a novel low-voltage piezoelectric direct discharge generated cold plasma (CAP) and linalool-loaded nanoemulsion washing (LW) was assessed against Salmonella and Escherichia coli O157:H7 on ready-to-eat (RTE) chicken meat. The antimicrobial activity of the nanoemulsified linalool and its effect on cell membrane permeability were also determined in vitro. Nanoemulsified linalool showed similar antimicrobial activity against Salmonella and E. roll O157:H7. The antimicrobial activity of CAP (0-5 min) and LW (0-25 min) treatments were determined individually and in combination in different sequence of application on RTE chicken. Individual treatments of CAP (5 min) and LW (25 min) achieved similar reduction levels for E. roll O157:H7 and Salmonella (1.4-1.8 log CFU/g). The combination of CAP (5 min) followed by LW (25 min) showed the highest reductions, 2.76 and > 3.24 log CFU/g for E. roll O157:H7 and Salmonella, respectively, without significantly affecting the lipid oxidation levels of RTE chicken meat. This is the first report on the antibacterial effect of a piezoelectric direct discharge generated cold plasma to enhance food safety. Cold plasma, alone or in combination with linalool nanoemulsions, can be adopted by the food industry for decontamination of RTE chicken meat.
查看更多>>摘要：The aim of this study was to determine the botanical origin, phenolics, flavonoids and fatty acids content, antioxidant and antimicrobial properties, of 18 bee collected pollen (BP) samples from Turkey and Romania. Five plant families with predominant pollens (>45%) were found in the Turkish samples, and only three in the Romanian samples. The phenolic content, varied between 16.40 and 41.17 mg GAE/g and the flavonoids content varied between 2.39 and 7.17 mg QE/g. The highest value of DPPH was 2.93 mmol Trolox/g and 9.64 mmol Trolox/g for the TEAC, whereas the IC50 value of alpha-Amylase inhibition was 8.10 mg/mL. We also verified that the presence of the methanolic extract of BP differentially affected the growth of Gram-positive and Gram-negative bacteria under study, strongly depending on the microorganism and the botanical origin of the BP samples used. The fatty acids contents were closely correlated with the above-mentioned parameters especially with the botanical origin and antibacterial activity. Our findings suggest that BP is a rich source of unsaturated fatty acids and bioactive compounds, which can be considered a value-added product. Furthermore, the differences in Turkish and Romanian BP chemical composition is also shown based on their antimicrobial and alpha-amylase inhibitory activities.
查看更多>>摘要：To date, few studies are found to compare the interfacial properties of protein aggregates with different structures and characteristics. In this research, different whey protein isolate (WPI) aggregates (native, nanoparticles, and nanofibrils) were fabricated, and characterized, and the emulsifying, and interfacial properties of WPI (native), its nanoparticle, and nanofibril as a function of pH values and salt concentrations were systematically investigated. The Z-average diameters of WPI (native), its nanoparticle, and nanofibril were 10, 355, and 122 nm, respectively. The isoelectric point (IEP) of native WPI was found to be approximately 5.0, whereas IEP of nanoparticles was decreased to 4.7, but increased to 5.5 for nanofibrils. WPI nanofibrils exhibited highest emulsifying activity index (EAI) and emulsifying stability index (ESI) at pH 3.0, whereas WPI nanoparticle had the highest EAI and ESI at pH 7.0. Low salt concentrations can increase the EAI and ESI of proteins. The EAI and ESI were highly correlated with the particle size, zeta-potential, and surface hydrophobicity of protein molecules. A negative correlation between interfacial tension of protein molecules and EAIs was observed regardless of protein types.
NSTL
Elsevier