查看更多>>摘要：Bacteriocins from lactic acid bacteria (LAB) arouse general concern in recent years due to their antimicrobial activities against foodborne pathogenic microorganisms. In this study, a novel bacteriocin named as bacteriocin ZFM54, produced by Lactobacillus paracasei ZFM54 isolated from the feces of newborn infant, was purified by a four-step strategy including macroporous resin XAD-16 adsorption chromatography, cation exchange chromatography, Sephadex G-25 gel filtration chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). The molecular weight of bacteriocin ZFM54 was 1143.39 Da, the predicted amino acid sequence was ATTLIPPVFGK. Bacteriocin ZFM54 was highly thermostable, active under the acidic condition, sensitive to trypsin and proteinase K, while insensitive to a-amylase, lysozyme, lipase, and ribonuclease A. The bacteriocin possessed a broad-spectrum inhibition against many foodborne pathogens such as Salmonella typhimurium, Micrococcus luteus and Listeria monocytogenes. The mode of action of bacteriocin ZFM54 was related to the pore formation of cell membrane. We further demonstrated that Lipid II, the molecular target of the prototype lantibiotic Nisin, was not the specific target of this bacteriocin. Together, this new bacteriocin has great potential to be used as a biological preservative in the food industry.
查看更多>>摘要：The aim of this study was to examine the effects of thiol compounds, glutathione (GSH), cysteine (CYS) and N-acetylcysteine (NAC), on the color, antioxidant activity, total phenolic, ascorbic acid and acrylamide content of French fries which were fried at 180 degrees C for 6 min. Three different concentrations (0.5%, 1.0%, 2.0%) of each thiol compound were tested. Sulphite solution was used as a benchmark. According to the results, CYS and NAC solutions increased the antioxidant activity but GSH solution did not affect. The amount of ascorbic acid was highest in CYS (1.0%, 2.0%) and GSH (2.0%) treated samples. Although all pre-treatments decreased the acrylamide content, GSH2.0%, NAC2.0%, CYS (0.5%, 1.0%, 2.0%) provided 62-70% reduction. In addition, acrylamide showed a high correlation with L* (r=-0.82), a* (r=0.84), b* (r=0.77), Delta E (r=0.66), ascorbic acid (r=-0.79) and weak correlation with thiol content (r=-0.45). On the other hand, antioxidant activities had lack of correlation with acrylamide.
查看更多>>摘要：Antioxidant peptides confer numerous health benefits. Unexplored niches provide bioprospection opportunities for potential protease producing microorganisms that are useful in releasing antioxidant peptides from protein sources impacting human health. A cold-adapted bacterium Chryseobacterium polytrichastri ERMR1:04 produced an extracellular protease enzyme optimally at 20 degrees C, pH 8 with 1.25 g/100 mL skim milk inducer. The purified 22.24 kDa protease was active over a broad temperature 5-65 degrees C (optimum at 37 degrees C) and pH 6-10 (optimum at pH 8) range, inhibited by EDTA and 1, 10-phenanthroline, enhanced by Ca2+, Mn2+ and hexane, and retained its activity with surfactants and detergents. ERMR1:04 protease-mediated hydrolysis of soy protein generated antioxidant peptides of <6 kDa, with successful identification, showing radical scavenging activities of 77% DPPH, 96% ABTS, 93% ferrous ion chelation, and Abs(700) 0.159 for reducing power assay. Such promising properties qualify the ERMR1:04 protease as a potent catalyst for high-value functional food production.
查看更多>>摘要：Galacto-oligosaccharides (GOS) are prevalent prebiotic ingredients of various functional foods. GOS synthesis by beta-galactosidase from whey-derived lactose results in a crude GOS mixture containing additionally lactose, glucose and galactose. In this study, we assessed the potential of lactic acid bacteria for depleting non-GOS sugars from crude GOS by selective fermentation. We aimed to combine the prebiotic characteristics of purified GOS with the health promoting effects of lactic acid fermentation metabolites. Our results indicated that supplementation of crude GOS with casein hydrolysate and retardation of acidification during fermentation stimulated cell growth, mono- and disaccharide consumption, overall organic acid production and diversity of the produced acids. Fermentation performed by Lactobacillus paracasei PB9 and L. plantarum 2108 resulted in lactic and citric acid containing high purity GOS media with a final pH below 4.6. We assessed the products as nutritionally safe that open a way to the formulation of prebiotic fermented beverages. Moreover, lactic fermentation of crude GOS would offer an alternative to the end-to-end valorization of whey-derived lactose.
查看更多>>摘要：The study was undertaken to determine selected properties of pasta supplemented with Moldavian dragonhead defatted flour (MDF) (by-product of oil extraction), added to the recipe up to 25 g/100 g. The pasta was evaluated with respect to the cooking quality (optimum cooking time (OCT), cooking losses (CL), weight increase index (WII)), firmness, color, nutrients content, and sensory characteristics (surface appeal, color, smell, taste, hardness, stickiness, overall acceptability, sensory acceptance index). The addition of MDF decreases the pasta extruder output up to 40%. The pasta fortified with MDF had higher OCT, CL, WII, and lower firmness, compared to control sample (100% semolina). It was concluded that MDF can be used in the concentration of 10 g/100g resulting in pasta with high nutritional content and sensory acceptance. This level of addition of MDF provided nutritional increase of 5.8% in proteins, 145% in dietary fiber and 50% in minerals, without negative affecting the cooking and sensory characteristics of pasta. This formulation resulted in sensory acceptance index of 88%. Furthermore, MDF is characterized by good composition of fatty acids with a high share of linolenic (62.21%) and linoleic acids (20.39%). Thus, MDF-fortified pasta can be used by consumers which look for a healthier diet.
查看更多>>摘要：This study aimed to improve the industrial production of Bifidobacterium adolescentis strain Z25 by establishing a method that could rapidly evaluate proliferation efficiency in response to different carbon, and nitrogen sources, inorganic salts, trace elements. Notably, glucose, yeast extract, fish peptone, Mg were the optimum substrates for high-efficient proliferation of the strain. The inorganic salts were not required in a pH-controlled culture. Both batch culture and automatic feedback feeding culture methods were optimized and compared. The maximum proliferation efficiency was achieved when the carbon-nitrogen ratio was equivalent to the carbon-nitrogen consumption ratio at the point of growth rate inhibition and the osmotic pressure of the medium was lower than 550 mOsm kg(-1). Within a certain concentration range, the maximum biomass was positively correlated with the concentration of Mg2+. The automatic feedback feeding method was more conducive for a high-density bifidobacterial culture. Finally, at the optimum pH of 5.5 and the initial medium osmotic pressure of 312 +/- 6 mOsm kg(-1), the viable bacterial count reached (1.6 +/- 0.1) x 10(10) CFU mL(-1) after 15 h with a feed liquid containing 320 g L-1 glucose, a 20-fold increase compared to the yield obtained with the original culture method and MRS medium.
查看更多>>摘要：To obtain the predominant drying speed period of sliced persimmon during hot air drying, the aim of this study was to evaluate drying kinetics, effective diffusivity and its activation energy under different drying temperatures (50, 60 and 70 degrees C). Besides, the bioactive compounds, antioxidant activity and microstructure after drying were also compared with those of freeze-dried persimmon. Results showed that water loss of persimmon slices during hot air drying followed the second-order kinetic model. The effective diffusivities of sliced persimmon at 50, 60 and 70 degrees C were 6.45 x 10(-7), 7.48 x 10(-7), and 9.08 x 10(-7) m(2) s(-1), respectively. No significant (p > 0.05) differences in the drying rate at different drying temperatures (50, 60 and 70 degrees C) after 180 min of drying were observed. Contrarily, increase of hot air drying temperature resulted in a significant decreases in majority of bioactive compounds. While, considering the high price and time consumption of freeze-drying technique, as well as the fact that higher drying temperatures did not further affect the drying rate after a certain drying time, controlling the temperature gradient during hot air drying processing might be useful in minimizing energy input and improving the retention of bioactive compounds during the processing of dried persimmon in food industry.
查看更多>>摘要：This study was undertaken to isolate a sulfated polysaccharide from red macro alga Falkenbergia rufolanosa (FRP) and to evaluate its potential effect as antioxidant additive in beef sausages formulation. The antioxidant, functional and hemolytic activities were studied. Data revealed that this polymer has an important antioxidant activities (up to 87% for metal chelating assay) and emulsion stabilizing capacities. The addition of FRP into sausages stored at 4 degrees C for 12 days induced depletion in lipid oxidation, in myoglobin oxidation and in free fatty acids contents up to 3.33 mg equivalent MDA Kg(-1) Sausages, 28.28% and 2.35%, respectively, while, an improvement in the transformation of the Heme iron was noted, compared with the standard formulation. A significant stability in the color parameters (L*, a* and b* values) with a marked decrease in the microbial counts were as well noticed. Interestingly, a significant progression in the textural parameters of samples containing FRP was observed as well as higher sensory scores by panelists. According to sensorial evaluations, this polymer improved the consumer acceptability and preference. In conclusion, our findings provided evidence that FRP could be used as a potent natural additive and could replace synthetic antioxidant compound in food industry.
查看更多>>摘要：Fucoidan has coating forming ability and antibacterial activity. This study aims to investigate the effects of fucoidan coatings on the shelf-life of mango fruits. Fucoidan coatings of different concentrations (1%, 3% and 5%) were used to extend the shelf life of mango fruits at room temperature (temperature similar to 20 degrees C, humidity similar to 80%), and a blank control experiment was conducted. Optimum preservation effects of fucoidan coatings on mango fruits were observed at the highest concentration of fucoidan. At the highest dose, fucoidan coatings delayed the respiratory peak by three days, and the respiratory peak even appeared one week later. After 35 days of storage under room-temperature conditions, the mango fruits had a weight loss rate of 5.91%, the fruit decay incidence was 14.2%, the ascorbic acid content was 19.14 mg/100 g, the soluble solid content was 19.73%, the hardness was 0.77 Kg, the titratable acid content was 0.52% and overall acceptability was 7.3. Results indicated that fucoidan coatings can effectively extend the shelf life of mango fruits.
查看更多>>摘要：Edible oil is easy to be polluted by polycyclic aromatic hydrocarbons (PAHs) in production, processing, storage and use. Rapid screening of oil quality and safety is a huge demand in food industry and government regulation. Usually, sample pretreatment is needed for PAHs detection due to the complexity of the oil base but greatly limits the detection speed. Here we develop a liquid-interfacial surface-enhanced Raman spectroscopy (SERS) technology without sample pretreatment to realize the rapid and direct detection of ultra-trace PAHs in edible oil within 3 min. A quantitative analysis curve of benzopyrene (BaP) content in soybean oil is established in the range of 0.1 ppb-100 ppm with a high coefficient correlation (R-2) of 0.9959 in curve fitting. It was found that only 4.5 h of frying would make the BaP content exceed the limit of 10 ppb in the Chinese Food Safety National Standard. Four common PAHs can be quickly identified in frying oil samples collected from special snack streets and the SERS profiles of soybean oil with adulteration of refined gutter oil could be well classified. This study paves a reliable method to rapid analyze edible oil with broad application prospects in the field of grain and oil safety.
NSTL
Elsevier