查看更多>>摘要：In order to overcome the issues (losses of neutral oil and trace nutrients, waste discharge and great energy consumption) in the traditional degumming and deacidification processes of corn oil, a new refining process using alkali aqueous solution was developed. The miscella of corn oil was used to investigate the effect of the refining process on acid value and phosphorus content of corn oil. Results showed that phospholipids and free fatty acids can be simultaneously successfully removed using this one step method. Under the optimized conditions (50 g/100g miscella oil concentration, 30 g/100g excess alkali, 10 degrees Be alkali concentration and 150 rpm at 50 degrees C for 60 min), the phosphorus content and acid value of corn oil can be decreased from 587.57 +/- 10.32 mg/kg and 5.13 + 0.51 mgKOH/g to 5.79 +/- 1.49 mg/kg and 0.10 mgKOH/g, respectively. High oil yield (95.3 g/ 100g) was achieved at low temperature (50 degrees C). The washing process was saved and no waste water was formed in this method.
查看更多>>摘要：This study was conducted to determine the most efficient method to produce vitamin D in mushrooms using UV radiation. For this purpose, mushrooms were irradiated with UV-B and UV-C lamps from their caps, stems, both caps and stems (oblique), and sliced surface at doses of 12.5 kJ m(-2) and 3.6 kJ m(-2), respectively. Then, they were treated by UV-B at 27 degrees C, 35 degrees C, and 43 degrees C. In the next steps, samples were placed in 30 cm and 50 cm distances from the UV source. Afterward, they were irradiated from 15 to 120 min at an intensity of 3.5 W m(-2). In the stability tests, samples were stored at 25 degrees C, frozen, refrigerated and were cooked and their vitamin D2 content was re-analyzed using HPLC. All experiments were repeated three times. In the sliced group treated with UV-B, vitamin D2 content 14.43 mu g gr(-1) was significantly higher than other groups. The internal temperature of 27 degrees C was found as optimum temperature with the production of 3.81 mu g gr(-1) vitamin D. It was revealed that increasing the distance from the UV source had a significant effect on vitamin D production. After 90 min of exposure, the highest amount of vitamin D2 was produced. Data showed that the vitamin D2 content remained almost stable after one day at 25 degrees C and during the cooking but it decreased about 50% after 7 days of cold storage. The optimal method observed in this study incorporates the use of UV-B lamps, incensement of radiation area in mushrooms and distance reduction from the UV source within 30 cm the internal temperature of 27 degrees C should be considered as well in the experiment.
查看更多>>摘要：Several studies showed that lactic acid bacteria isolated from traditional cheeses produced in Calabria (Italy) inhibited in vitro the growth of different spoilage and/or pathogenic microorganisms. However, the activity of these autochthonous strains against Listeria monocytogenes has never been investigated. One hundred and fifteen lactic acid bacteria isolated from traditional Calabrian cheeses were screened for their technological characteristics and inhibiting action against Listeria monocytogenes in laboratory media. The anti-Listeria activity of representative strains was evaluated also in soft cheese during chilled storage. Bacterial interaction was studied using a competitive modelling approach based on Lotka-Volterra equations. Strains 29 (Lactobacillus sakei), 31 (Lactobacillus plantarum group), and 76 (Lactobacillus plantarum group) showed the best performances both in vitro and in soft cheese reducing the loads of Listeria monocytogenes from 0.5 to almost 1 Log CFU/g. Also considering their technological features, these strains could be used as adjunct cultures to improve the safety of finished products. The proposed competition model returned good predictions, especially after the application of the interspecific competition parameter beta. This approach may be useful to understand the mechanisms of microbial competition in food.
Santos, Suzana C.Fortes, Gilmara A. C.Camargo, Lilian T. F. M.Camargo, Ademir J....
8页
查看更多>>摘要：Phenolic antioxidants form a class of compounds which inhibit the oxidation of materials of biological importance, playing a preventive role in a number of degenerative diseases. Polyphenol activity depends on their chemical structure, which is influenced by factors such as number and position of phenolic hydroxyl groups, steric effects, and molecular properties. In this research study, 18 polyphenol structures (13 hydrolysable tannins, 4 flavonoids and ellagic acid) were modelled and their molecular properties (volume, area, dipole moment, polarisability, LogP, E-HOMO, E-LUMO, and E-LUMO-E-HOMO gap) calculated by density functional theory (DFT), using the M062X/6-311 + G (d,p) level of theory. Multivariate regression tree (MRT) and canonical redundancy analysis (RDA) were applied to correlate the experimental antioxidant activities obtained by ORAC and DPPH assays and molecular and lipophilic parameters. MRT/RDA split all 18 polyphenols into four clusters with increasing antioxidant capacity. Flavonoids and galloyl esters belong to clusters C1-C3, while cluster C4 is composed mainly of monomeric and dimeric ellagitannins. The RDA1 axis shows a positive correlation between antioxidant activity and parameters polarisability, E-HOMO, and LogP. These molecular properties proved to be the most suitable for predicting the relationship between chemical structure and antioxidant capacity for this group of phenolic compounds.
Zhang, DejuLillevang, Soren KristianShah, Nagendra P.
11页
查看更多>>摘要：The purpose of this study was to investigate the effect of konjac glucomannan (KGM) and microparticulated whey protein-based fat replacers (WPFR) on low-fat Mozzarella cheese. The textural properties, meltability, color, microstructure and pizza bake performance of 0, 7, 14, 21, 28-day-old low-fat cheeses using KGM (LFKGM) or whey protein (LFFR1 and LFFR2) were studied, and fat-reduced cheeses (LFC; milk containing 1.40 g fat/100 g milk) and full-fat cheeses (FFC; milk containing 2.24 g fat/100 g milk) were manufactured as control. The color of Mozzarella cheeses was closely linked to their composition and storage time, especially moisture and fat content and the lightness values of FFC, LFC, LFKGM, LFFR1 and LFFR2 were 90.28, 84.91, 88.48, 91.77 and 91.57, respectively. Textural properties, meltability and baking performance of Mozzarella cheeses generally improved with the supplement of KGM or WPFR and with age. The addition of whey protein or KGM showed much denser microstructure and reduced pockets of serum channels distributed in the protein network throughout refrigerated storage. Positive changes of low-fat Mozzarella cheeses as affected by KGM or whey protein were observed in our study, suggesting WPFR could improve the functionality of cheeses and could be used to reduce fat in dairy products.
查看更多>>摘要：Fresh fish are highly perishable because their high content of protein and unsaturated fatty acids are easily oxidized and/or degraded under the influence of bacteria and the external environment. In this study, four natural preservatives (phenyllactic acid, kojic acid, tea polyphenols and thymol) were initially screened for antimicrobial activity against spoilage bacteria commonly found in fish by in vitro antibacterial tests. The results suggested that kojic acid (KA) and tea polyphenols (TP) exhibited a strong synergistic antibacterial effect against spoilage bacteria. Hence, the effects of KA and/or TP on the preservation of refrigerated sea bass (Lateolabrax japonicus) fillets after soaking treatments were determined. Changes in physicochemical parameters, indexes of fish freshness and microbial enumeration were examined. KA, TP and KA-TP treatments were effective in inhibiting bacterial growth and delaying lipid oxidation in fish flesh, resulting in lower TVB-N and TBARS than the control. Meanwhile, the freshness and physical qualities (color and texture) of fish fillets were also stabilized by the three treatments. Moreover, the KA-TP treatment showed the best effect on refrigerated fish preservation among the three treatments and extended the shelf-life by 5-6 days, suggesting that KA-TP have the potential to become a compound preservative for aquatic products.
查看更多>>摘要：The aim of current work was generation soy milk in the form of the wet foam and clarify the controlling factors of foamability and foam stability. Soy milk foam (SMF) was prepared with the help of whey protein concentrate (3 and 6% w/w) and hydrocolloids (xanthan, guar and locust bean gums (0.05 and 0.15% w/w) at different temperature (5, 40 and 75 degrees C). The overrun of SMFs was not greatly impacted by increasing guar gum concentration from 0.05% to 0.15%, whereas foam stability was greatly enhanced. When 0.15% xanthan gum was added to the samples, a great decrease on drainage was observed but they showed the lowest overrun. Also, in general, SMFs produced at temperatures of 5 and 75 degrees C showed the highest overrun and stability, respectively. To summarize the basic physical properties of foam data (overrun, and drainage), hierarchical clustering analysis was performed. Samples from different classes evaluated for surface tension, zeta potential, rheological behavior and bubble properties to find factors controlling the formation and stability of foams. It was observed that the SMFs exhibited viscoelastic properties. Results showed that foam stability was directly related to rheological parameters (consistency coefficient, static and dynamic yield stress, zero shear viscosity, storage modulus, loss modulus, complex modulus and complex viscosity) and, except one sample, showed a negative correlation with surface tension. Overrun showed a positive correlation with the bubble counts and a negative correlation with the average bubble diameter. But microstructure changes cannot necessarily represent foam stability. Also, zeta potential could not explain any differences in the foam properties.
查看更多>>摘要：This work assessed the effect of storage time on the structure and functionality of HHP-treated whey protein isolate (WPI). Different pressures (100-600 MPa) and treatment times (15-30 min) were applied to aqueous WPI dispersions (5% w/v). The induced degree of unfolding was evaluated to select optimal HHP treatment conditions of WPI before storage at 4 degrees C. Conformational and techno-functional properties of untreated and optimally HHP-treated WPI samples were determined by UV-Vis and IR spectroscopy, foaming capacity, and interfacial tension measurements, respectively. Further tests of HHP-assisted hydrolysis of WPI were performed by alpha-chymotrypsin, bromelain, or their mixture (1:1 w/w), with the degree of hydrolysis (DH%) and electrophoretic patterns analyzed.
查看更多>>摘要：Blueberries are non-climacteric fruits which have a limited shelf life due to the activities of rapid decay and softening. Coatings are eco-friendly by nature which helps in prolonging fruits and vegetable storage life. This research was carried out to determine the effects of nano-coatings on blueberries' life extension with 50-65% humidity for 8 days at ambient temperature. Different formulated coatings of chitosan (BC), chitosan/nano-titanium dioxide (BC-NT), and chitosan/nano-titanium dioxide (tween-thymol) (BC-NT-TT) were developed and used to check their effectiveness against some physical, mechanical and biochemical properties in addition to microbiological analysis and sensorial evaluations. The use of BC-NT-TT coating treatment was proved to prolong storage life as well as several quality parameters like weight loss (1.97%), decay rate (5.56%), shrinking rate (32.69%), ascorbic acid content (7.78 mg/100 g), appearance, texture, and antioxidant enzymes. Moreover, BC-NT-TT coating lessened the mesophilic aerobic bacteria, mould, and yeasts counts. BC-NT coatings enhanced pH (3.07), soluble solids content (9.64 degrees Brix), ripening index (21.42), and as well as anthocyanins (65.76 mg/100 g). BC coating significantly described the highest titratable acidity (0.41%) value. An over-all sensorial evaluation has remained acceptable and the final results indicated that BC-NT-TT should be used for preservation instead of other expensive and artificial chemicals.
查看更多>>摘要：The technical features of biodegradable films depend on several manufacturing parameters. Exploiting these films on an industrial basis requires statistical models for the fast and effective evaluation of these parameters. This study analyses the impact of compositional and drying factors on the microstructural and functional properties of films based on chitosan and pectin through a multivariate approach. A total of 32 formulations were developed and the results were analysed through principal component analysis (PCA). Four formulations did not form films due to the photodegradation caused by prolonged UV-C irradiation. Films containing glycerol had a higher elasticity (1.5-39%) than those with propylene glycol or that were not plasticized (1.2-12%). Glycerol increased the thickness of pectin films (56-77 mu m). Sodium trimethaphosphate (STMP) enhanced the UV mean absorbance of both pectin and chitosan films (0.7-1.7). In addition, STMP led to an increase of thickness (72-129 mu m) and air permeability (38.6 x 10(3) to 9206.1 x 10(3) cm(3)/m(2) x day x kPa) of the chitosan films, while CaCl2 led to a decrease of thickness (31-59 mu m) and air permeability (23.9 x 10(3) to 46.8 x 10(3) cm(3)/m(2) x day x kPa) of the pectin films.
NSTL
Elsevier