查看更多>>摘要：A buckwheat trypsin inhibitor mutant with enhanced activity (rEBTI) was expressed, purified, and immobilized onto Sepharose CL-4B matrix. The optimum pH for the adsorption by, and desorption of porcine trypsin from the rEBTI-Sepharose CL-4B column were 8 and 3.5, respectively. The rEBTI-Sepharose CL-4B was applied to purify trypsin from grass carp hepatopancreas to verify its practical utility. The enzyme was purified by one-step chromatography and migrated as a single band with molecular mass of 27 kDa from sodium dodecyl sulfate polyacrylamide gel electrophoresis. The optimal temperature and pH of the purified enzyme were 60 degrees C and 9.5, respectively, and it was stable within pH 6.0-12.0. The apparent K-m value of the purified enzyme was determined as 3.4 x 10(-5) M using N-benzoyl-DL-arginine-nitroanilide as substrate. The trypsin was activated by Ba2+ and Mg2+, but was inhibited by Zn2+, EDTA and vitamin C. The novel trypsin affinity material rEBTI-Sepharose CL-4B could obtain grass carp trypsin of high purify by one-step purification, which is less tedious and more cost-effective than most current methods. The process can produce the enzyme in high purity to meet high-end biotechnological applications in the biomedical and pharmaceutical industries.
查看更多>>摘要：This is the first report on the effective utilization of the deep sea for improving food quality. Long-term aged fish has recently received substantial attention because of improved taste quality and the sustainable utilization of fishery resources. However, problems such as the refrigeration energy and space limitations for aging remain. Therefore, effects of deep-sea aging at a 2034 m depth for 34 days on meat quality of greater amberjack and bluefin tuna were investigated with a focus on changes in taste components and texture. Our results showed that free amino acid (FAA) contents in the deep-sea-aged greater amberjack were higher than those in the laboratory-aged sample. The deep-sea method promoted the proteolysis involved in FAA generation and mitigated the degradation of inosine-5'-monophosphate in greater amberjack. Conversely, deep-sea aging did not improve the quality of bluefin tuna. The present study also showed that the increase in the total viable bacteria count could be suppressed in greater amberjack during deep-sea aging. Thus, the deep sea can be utilized for sustainable aging of fish with superior quality, even though its suitability might depend on the fish species and depths related to the pressure level.
查看更多>>摘要：In this study, we developed an ultrasound-assisted double enzyme hydrolysis method for the extraction of low molecular weight peptides (LMWP) from bovine bone and determined the optimal process using response surface methodology (RSM). Moreover, we have discussed the effect of the extraction methods on the structure and antioxidant properties of bovine bone peptides (BBPs). Results from RSM studies showed that the optimal extraction yield of 21.04% was obtained when the experimental parameters were 76.25 x 104 U/g of the enzyme addition, an ultrasonic power of 413.90 W/L, pH of 9.00, and ultrasonic time of 2.01 h. The BBPs obtained using ultrasound-assisted enzyme hydrolysis (UDE) were appeared as small granules, uniform in structure, and exhibited a rough surface. Moreover, the BBP was found to have obvious amide I, II, and III band structures and an increase in hydrogen bonding, as determined using FTIR and NMR. In addition, the peptide extracted using UDE had the optimal antioxidant effect (P < 0.05). Thus, UDE is an efficient method for the extraction of LMWPs from bovine bone. This method can be used in an industrial extraction of bone peptides as it can have a positive effect on resource re-utilization of bovine bone.
查看更多>>摘要：The effects of fermentation with Lactobacillus plantarum on the volatile flavors of mung beans were studied using a gas chromatograph-ion mobility spectrometer, electronic nose, relative odor activity values and sensory evaluation. The main volatile compounds in unfermented mung beans were aldehydes such as nonanal, octanal and butanal, and esters such as ethyl hexanoate and ethyl acetate. The relative contents of the beany flavor components (1-octen-3-ol, hexanal and hexanol) were relatively high in the unfermented samples. The main volatile compounds of fermented mung beans (FMB) were acetic acid, ethyl hexanoate and ethyl acetate. The relative content of the beany flavor components in FMB decreased significantly, with hexanal changing the most. L. plantarum 23169 was most effective at removing the beany flavor. The electronic nose results showed that the flavor of L. plantarum 23169 FMB and L. plantarum 22699 FMB changed most and were similar, but the flavors from the three FMB samples could still be clearly distinguished. According to relative odor activity values, the special smell of FMB were fruity and grassy with no beany flavor, and sensory evaluation showed that L. plantarum YI-Y2013 provided a good "deodorization" effect, with the most obvious aromatic flavor and a high overall flavor coordination.
Trujillo-Santiago, E.Villalobos-Delgado, Luz H.Guzman-Pantoja, L. E.Lopez, M. G....
9页
查看更多>>摘要：The antioxidant and antimicrobial effects of Hierba Santa (Piper auritum Kunth) ethanolic extracts (HSEE) from plant powder of particle sizes 425 mu m (EPA) and 850 mu m (EPB) were evaluated in raw and raw-cooked beef burgers stored for 9 days at 4 degrees C, as well as raw-frozen and raw-frozen-cooked beef burgers stored for 90 days at 20.C. Four treatments were prepared, including control (without extract), solution of sodium ascorbate (NaASC at 500 mg/kg), MEPA (meat with HSEE from EPA at 750 mg/kg) and MEPB (meat with HSEE from EPB at 750 mg/kg). The in vitro antioxidant and antimicrobial activities as well as total phenolic, chlorophyll and carotenoid content of HSEE were studied. The chemical composition was evaluated in beef used for the burgers. Beef burgers were evaluated for thiobarbituric acid reactive substances (TBARS), pH, color, metmyoglobin content and microbial load. Results indicated that HSEE showed in vitro antioxidant activity and their incorporation in beef burgers inhibited lipid oxidation compared with NaASC, while pH was lower than the maximum allowed limit. However, neither EPB nor EPA were effective in reducing the total bacteria count (TBC) in raw beef burgers. Therefore, HSEE could be recommended as a natural antioxidant in beef burgers.
Pravitha, M.Manikantan, M. R.Kumar, V. AjeshBeegum, Shameena...
9页
查看更多>>摘要：Coconut slices were converted into healthy coconut chips by replacing conventional osmotic agent with jaggery to counteract the health deteriorating effect of refined sugar. The optimal processing condition to yield the desired product was determined by employing a Box-Behnken design based on independent variables: drying temperature (50-70 degrees C), jaggery solution concentration (45-55 degrees Brix), and slice thickness (0.50-1.00 mm). The simultaneous optimization of these processing parameters was done based on the responses: final moisture content, drying rate, rehydration ratio, crispness, appearance, taste and overall acceptability. Further, the sample prepared at the optimized condition (drying temperature - 66.22 degrees C, slice thickness - 0.55 mm and jaggery solution concentration - 46.18 degrees Brix) was characterized and compared with traditional refined sugar osmosed coconut chips. Proximate and mineral analysis of the optimized sample suggested that incorporating a new osmotic agent, jaggery, has improved the nutritional quality of the chips with higher consumer acceptability.
Staniszewska, IzabelaDzadz, LukaszNowak, Konrad W.Zielinska, Magdalena...
8页
查看更多>>摘要：The aim of study was to evaluate the storage stability of microwave-vacuum dried (MWVD) and hot air convective dried (HACD) powdered coriander, parsley and celery leaves based on their moisture sorption isotherms and glass transition temperatures (T-g). Dried coriander, parsley and celery leaves were powdered and kept at a storage temperature (T-S) of 20 degrees C for 10 weeks with a water activity ranging from 0 to 0.813 until equilibrium was reached. The values of coefficient of determination (R-2 > 0.99) and percentage global relative square error of the approximation (4.9<GRSE<11.3%) indicate that Guggenheim-Anderson-de Boer (GAB), Peleg, Lewicki, Curie and Oswin models well described the relationship between water activity (aw) and the equilibrium moisture content (EMC) of dried materials. The variations in T-g vs. a(w) or EMC were adequately predicted by linear, square, polynomial, Khalloufi, Gordon-Tylor and Jenckel-Heusch models (R-2 > 0.81; 2.95<GRSE<43.5%). For the optimum range of aw (0.2 <a(w) < critical a(w)), dried powdered coriander, parsley and celery leaves showed the highest stability at EMC from 0.028 to 0.061, 0.022 to 0.074 and 0.027-0.064 g H2O/g DM, respectively. The optimum TS of dried powdered coriander, parsley and celery leaves was from 57.8 to 20.0, 61.3 to 20.0, and 69.8 to 20.0 degrees C, respectively.
查看更多>>摘要：High efficiency and green processing are the advantages of microwave heating (MWH), but firm and tough texture are the common quality defects in microwave-baked products. The aim of this work was to investigate the effects of sourdough on the quality properties of microwaved steamed-cake (MSC) and to illustrate the potential mechanism of textural improvement. The textural characteristics of MSC were improved significantly by sourdough addition, especially in specific volume, hardness and chewiness. Sourdough addition increased the dielectric properties of batter. Based on the low-filed 1H NMR analysis, the molecular motion of batter with sourdough on the MHz timescale was reduced as compared to the sourdough-free MSC. The addition of sourdough increased the extractability of protein and the concentration of free sulfhydryl during 120 s of MWH. Significant change in pasting properties of starch was also observed. Sourdough-induced formation of weakened and ordered protein network contributed to the quality enhancement of products by MWH. This study facilitates the development of sourdough-based products and it is a novel approach for adjusting the texture of microwavebaked foods.
查看更多>>摘要：During preservation of nuts, nut oils are easily oxidized; hence, peroxide value (PV) is an important evaluation index. In this study, a novel method for the determination of the PV of nuts based on partial-least-square regression (PLSR) and Forest random PLSR (RF-PLSR) model was established. Meanwhile, the Raman spectrum was processed by 24 spectral pretreatment methods to transform the whole Raman band, and the best band was selected by RF method. Among the whole bands, 36 wavenumbers were selected to establish the PLSR model. The R-square of the correction set (R2c) and prediction set (R2p) of the optimal Standard normal variate transformation + first Derivative-PLSR model and RF-PLSR were 0.9552, 0.8672, 0.8048, and 0.7927, while the root-mean-square error of calibration (RMSEC) and prediction (RMSEP) were 0.067, 0.1100, 0.1514, and 0.1547, respectively. These results showed that Raman spectroscopy combined with chemometrics could be used to establish a rapid, nondestructive, and precise method for the determination of oil oxidation index.
查看更多>>摘要：New and unconventional sources of probiotics may provide unique health efficacy by producing healthy, bioactive compounds. The current study evaluates the fermentation efficiency and intrinsic effects on the bioactive substances produced by Lactobacillus apis (L. apis) as a novel strain isolated from the bumblebee gut, two different isolated Lactobacillus communities from breast milk (L.BM) and camel milk (L.CM). Lactobacillus plantarum (L. plantarum) was used as a reference during rice and oats fermentation. The obtained results indicated that L.BM and L.CM treatments gave the highest production of phenolics and flavonoids values for different substrates and had the highest impact on the antioxidant capacity. All treatments demonstrated the ability to improve protein quality and properties significantly as compared to non-fermented flours. The best patterns were obtained with L.BM, followed by L. apis and L.CM compared with L. plantarum and non-fermented rice samples. The L.BM and L. apis showed a significant enhancement of volatile components in fermented rice, while L.CM displayed a pronounced effect on volatile production among oats treatments.
NSTL
Elsevier