查看更多>>摘要：This study presents as a novel rice bran (RB) treatment method for gluten modification. The effects of the method on viscoelastic, and antioxidant properties, as well as the structure of wheat gluten were investigated. RB treatment improved the viscoelastic properties and antioxidant activities (Oxygen radical absorbance capacity and DPPH radical scavenging activity) of modified gluten. Additionally, the modified gluten showed a higher polyphenols content (especially bound polyphenols) and higher percentage of branched chain amino acids compared to control gluten. RB treatment achieved these effect by triggering aggregation of gluten and reaction between amino (-NH2) groups of lysine of gluten proteins and RB polyphenols thereby strengthening its network structure and changing its fluorescence. Moreover, increase in fl-turn conformation proved the improvement of gluten aggregation. This study demonstrates that RB treatment modifies the characterization of gluten, and this approach reduces the cost of producing modified gluten and promotes the utilization of RB.
查看更多>>摘要：A strain of Aspergillus ochraceus was isolated from the stored low denatured soybean meals (LDSMs) and an extracellular protease was purified from the fungus grown culture to electrophoretical homogeneity. The protease had a molecular weight of approximately 70 kDa and showed proteolytic activities only in the presence of activators. The maximum activity was obtained in 1.4% sodium dodecyl sulfate (SDS) solution but similar activity could also be achieved in the presence of linoleic acid at the concentration as low as 0.05%. The protease was stable at pH 9.0-12.0 and remained active in the presence of methanol, ethanol, acetone and trichloromethane and was classified as serine protease. The thermal stability of the protease located in the temperature range of 4-40 degrees C and an activator independent autolysis was observed above 60 degrees C. Soy proteins was hydrolyzed by the purified protease in a model system using residual lipids from stored LDSMs as the activator and a degree of hydrolysis (DH) of 6.01% +/- 0.27 was obtained after reaction for 60 min at pH 9.0 and 40 degrees C. This study gives new insights into the quality control of the soy protein production and the use of fungal proteases in the modification of soy proteins.
查看更多>>摘要：Cu and Zn bioaccessibility was studied in two different beef cuts (rib plate and top sirloin), through the development of an in vitro assay. Samples were cooked at two degrees of doneness (medium and well-done) as usually consumed locally, to establish the contribution to the recommended daily allowance (RDA). Simulated gastrointestinal conditions were optimized and trueness of the method was evaluated by performing mass balances. Analytical determinations were performed by atomic absorption spectrometry and microwave-induced plasma optical emission spectrometry. No significant differences were found between the studied cuts nor between the degrees of doneness evaluated. Mean bioaccessible fraction (BF) of Zn was 83%, for both cuts and both degrees of doneness. In the case of Cu, rib plate presented a mean BF of 20%, while for top sirloin was of 38%. However, these differences found between cuts and degrees of doneness were not statistically significant. The contribution of Cu and Zn to the RDA for adults over 19 years was estimated, as an example, considering a 200 g portion. Results showed that the RDA of Zn would be completely covered, while the contribution to the RDA of Cu would be up to 33%.
查看更多>>摘要：In this study, we evaluated food stabilizing potential of nisin Z produced by wild Lactococcus (Lc.) lactis subsp. lactis from a total of 114 raw milk and naturally fermented products. After microbiological cultivation of lactic acid bacteria, Lc. lactis subsp. lactis strains identified by mass spectrometry were screened for the nisin Z gene by PCR. Nisin Z-production activity was studied under batch fermentation conditions, followed by testing food stabilizing potential of nisin Z extracted. Of 35 Lc. lactis subsp. lactis identified, 3 were nisin Z-producer, and one strain (e69) of natural cheese origin produced 2350 IU/mL at 63 degrees C for 30 min and 80 degrees C for 10 min, at pH 2.0. This nisin Z purified was moderately inhibitory on Gram (-) bacteria, stable at-20 degrees C and 4 degrees C during 6 weeks, influential on the shelf life of UHT milk and fruit juice at 30 degrees C from 2 to 6 weeks, and susceptible to lipase (89%), pepsin (92%) and catalase (84%) at 37 degrees C for 60 min, respectively. Overall, our study revealed that wild Lc. lactis subsp. lactis exhibited good activity in nisin Z production and native "clean-label" bio preservative potential for consumers and the food industry without biotechnological adaptation.
查看更多>>摘要：The present study aimed at exploring different properties of starches, isolated from commercial and non-commercial potato cultivars and to determine their suitability for developing a non-cereal pudding mix. The physico-chemical, functional and pasting properties of extracted starches varied significantly (p < 0.05) when compared with corn starch. Potato starches exhibited higher swelling power (27.69-34.54 g/g) and solubility (14.63%-20.43%), lower gelatinization temperature (69.75-70.89 degrees C), higher peak (5825-9239 cP) and final viscosities (4411-4891 cP) and lower set back viscosities (357-735 cP). The FTIR spectra observed for potato and corn starch was similar in terms of form and intensity of major peaks. Starch isolated from Kufri Pukhraj, an underutilized potato cultivar was selected for making non-cereal pudding mix based upon its distinct pasting properties i.e. higher peak (9239 cP), hold (4188 cP), final (4891 cP), and lower set back (703 cP) viscosity. Formulated mix was compared with pudding mix prepared with corn starch (control). Both samples (p < 0.05) differed significantly in terms of physico-chemical, functional and pasting properties. Sensory evaluation showed non-significant (p < 0.05) difference between non cereal pudding mix and control, indicating high potential of potato starch to replace corn starch in pudding formulations. Storage studies indicated that non cereal pudding mix can be stored for 12 months without impacting quality.
Marchetti, Marion DanielaLugo, Rolando Jesus JimenezMassa, Agueda ElenaCzerner, Marina...
9页
查看更多>>摘要：The salting-ripening of anchovy generates a large volume of residues that are discarded due to its high NaCl content. In this study, these residues are characterized and the suitability of desalination by immersion is assessed. Single-stage, using 0, 1, 3 and 5 %w/w NaCl solutions, and 3-stage (freshwater) desalting treatments were applied. The untreated residues presented a NaCl content of 17.6-55.9 g/100 g (%), with 12.8-14.8% of proteins and 2.4-3.5% of lipids. PUFAs fraction represented 9.8 and 20.3%, mainly comprised by EPA and DHA. 3-stage desalting treatment was more effective than the single-stage process for reducing NaCl content, reaching a final value of 1.6% in shorter time. The protein, lipids and PUFA final contents ranged from 9.4 to 14.2%, 3.8-5.0% and 15.7-20.9%, respectively, depending on the treatment performed. Protein retention percentages after desalting were greater than 65%. Non-significant lipid leaches were registered, and the proportion of fatty acid classes was not modified by the desalination processes applied. Our results show that salted anchovy residues present high proportion of nutrients that can be recovered through by-processing. Simple desalting process makes residues valuable to be reintegrated into different production cycles, such as fishmeal and oil production.
查看更多>>摘要：In the current study, thermal-denatured whey protein-milk fat emulsion gel microparticles (WPI-EGs) were used as stabilizers and fat replacers in low-fat yogurt. The effects of emulsion gel microparticles were studied on the texture, rheology, microstructure, and sensory evaluation of low-fat yogurt. The results showed that yogurt with WPI-EGs had a better (p < 0.05) water-holding capacity. The hardness of low-fat yogurt (1.50% (wt/wt) fat) added with WPI-EGs (1.5% LF-EY) increased (p < 0.05) significantly compared than skim yogurt and whole fat yogurt. Results from scanning electron microscopy showed that with the addition of WPI-EGs, yogurt has a more compact network structure and smaller pores. This study shows that WPI-EGs can be used as an effective fat replacer and stabilizer in yogurt. WPI-EGs have broad application prospects in dairy products, such as low-fat ice cream and processed cheese.
查看更多>>摘要：Regulated deficit irrigation (RDI) is a useful strategy to reduce the water consumption maintaining the fruit quality. The almonds cultivated under RDI conditions are called hydroSOStainable because are produced under environmentally friendly conditions and present an improved quality. It was demonstrated that almond cultivar and agronomical practices, can affect the kernel chemical composition and consequently the parameters for the roasting process of almonds. The influence of three roasting temperatures (150 degrees C, 170 degrees C and 190 degrees C) on the quality of almonds belonging to 2 irrigation treatments (T1: control and T2: hydroSOStainable almonds) was evaluated. For this, moisture, water activity (aw), organic acids, sugars, antioxidant activity (AA), total phenolic content (TPC) and fatty acids content were measured. Results showed that moisture content, aw, AA (ABTS(center dot+) and DPPH center dot), and polyunsaturated fatty acids (PUFAs) were reduced with the most severe roasting treatment. While citric, isobutyric, maltoheptaose and maltotriose content was increased. HydroSOStainable almonds had significantly higher content of AA, TPC, organic acids, sugars, PUFAs and total fatty acids than control almonds; this tendency was present at 170 degrees C, but not at 190 degrees C. Consequently, 170 degrees C during 10 min was the recommended roasting conditions for the hydroSOStainable almonds.
查看更多>>摘要：Adult Tribolium castaneum infesting canola seeds at 9% moisture content were treated using a 50-omega radio frequency heating system and the thermal mortalities of the insects were determined. The infested seeds were treated at temperatures of 24-65 degrees C with radiofrequency (RF) heating power at 3 kW, 5 kW, and 7 kW. More than 80% of the insects were killed at 65 degrees C at all the three power levels. The survival rate of the adult T. castaneum decreased with temperature and RF power level. The effect of selective heating on mortality of insects increased at the higher RF powers. An inverse simulation was used to estimate the kinetic parameters of thermal death in adult T. castaneum. The thermal kinetic models developed in this study were solved using the 4th order Runge-Kutta method on a MATLAB platform. The thermal death kinetics for adult T. castaneum followed the 1st order reaction with Ea of 97.50 kJ/mol and k(0) of 6.5 x 10(13). The lethal time (LTs) calculated using the thermal death kinetic model developed in the study agreed well with the LTs determined experimentally.
Martin-Garcia, BeatrizVerardo, VitoCerio, Elixabet Diaz deRazola-Diaz, Maria del Carmen...
10页
查看更多>>摘要：Air classification is a valuable process to obtain flours enriched in phenolic compounds. In this study, dehulled buckwheat grain flour was micronized and air classified obtaining two couple of fractions with different yields (fine fraction 70% and coarse fraction 30%, and fine fraction of 80% and coarse fraction 20%). The total content of phenolic compounds (by HPLC-MS) in coarse fractions increased 1.7-2.1 times compared to fine fractions. In addition, coarse fractions have shown a total phenolic content of 1.4-1.7 times more than dehulled buckwheat flour. Moreover, the antioxidant activity was evaluated using two different assays: FRAP (The ferric reducing antioxidant power) and DPPH (2,2-diphenyl-1-picrylhydrazyl radical). Coarse fractions have shown FRAP values 1.2-1.3 times higher than fine fractions, whereas the DPPH showed a slight increase in coarse fractions in comparison with buckwheat flour and fine fractions. In addition, FRAP and DPPH have exhibited a significative positive correlation with the flavonoids, phenolic acid derivatives and total phenolic content. These results have shown that air classification is an effective technique in order to obtain coarse flour fractions enriched in phenolic compounds such as swertimacroside, (epi)-afzelchin-(epi)-catechin-O-dimethyl gallate, rutin and caffeic acid hexose, among others.
NSTL
Elsevier