查看更多>>摘要：Truffles are a well-known worldwide product mainly appreciated by their unique aroma, which is composed by more than 50 volatile compounds. However, to this day, no one has accomplished to find the aromatic key that evokes the real aroma of truffles for its use as food flavoring. Among them, black truffle was selected for extraction with supercritical fluids using CO2 as solvent recovering natural truffle aroma fraction. To achieve the optimal extraction ratio, time, pressure and grapeseed oil addition to the separators were evaluated. Aroma from black truffle powder, extracts obtained, and residual cakes fractions were characterized by headspace gas chromatography-spectrometry and olfactometry techniques. The results indicated that optimal extraction conditions were 30 MPa for 3 h. Also, grapeseed oil addition enhanced trapping some key truffle aromatic compounds as 2,3-butanodione, 2-methyl-1-butanol, octanal and dimethyl disulphide. Olfactometry study showed the aromatic profile of the extracts indicating the molecules ethyl pentanoate (fruity), 1-hexen-3-one (metallic) and ethyl hexanoate (fruity) as the main compounds of extracts samples. For the first time, a natural truffle aroma has been obtained using low-value truffles. After aromatic extraction, carbohydrates, proteins, and phenolic compounds were analysed within the residues, showing a potential source of bioactive compounds.
查看更多>>摘要：The present study investigated the synergistic effects of low voltage electrostatic field combined with high humidity thawing (LHT) on the quality of pork steaks. Results indicated that LHT effectively maintained the colour stability of pork steaks by inhibiting the formation of metmyoglobin. Meanwhile, the thawing loss and centrifuging loss of pork steaks were significantly reduced (P < 0.05) in LHT group and low-field nuclear magnetic resonance (LF-NMR) results confirmed its improved WHC of muscle. Additionally, LHT samples displayed significantly lower hardness with higher springiness (P < 0.05) owing to its integrated muscle microstructure. Based on the thaw curve and PCA results, it can be concluded that the low voltage electrostatic field treatment could effectively shorten the thawing time and promote the WHC of muscle, while the high humidity seemed to play an important role in maintaining the colour stability of thawed pork. These results evidenced a potential application of the LHT method for meat thawing.
查看更多>>摘要：Surimi gelation at < 40 degrees C is termed "suwari". Unintentional suwari during the blending and shaping processes (before heating) in the manufacturing of surimi gel products causes serious challenges, because of imperfect molding and clogging in machines. To solve them, effects of transglutaminase and protease inhibitors on suwari gelation properties of Alaska pollock surimi were investigated at 25 degrees C. Furthermore, thermal gelation properties of surimi after the suwari suppression were studied for preparing gel products with superior physical properties. A 1.0 g/100 g N-ethylmaleimide (NEM) or ethylene glycol tetraacetic acid (EGTA) significantly suppressed suwari at 25 degrees C for 24 h. The surimi gel with 1.0 g/100 g NEM exhibited superior breaking properties, whereas those of the gel with 1.0 g/100 g EGTA deteriorated upon suwari suppression followed by heating at 90 degrees C. Adding 10 mu mol/L cysteine protease inhibitors, such as NEM or E-64, suppressed the peptide generation in surimi at 25 degrees C (1.7-2.5 mu g/mL) compared to that in the control sample (12.2 mu g/mL). Therefore, the inhibition of both transglutaminase and cysteine protease activities was essential for prolonged suppression of the suwari phenomenon and obtaining the heat-induced surimi gel with superior physical properties after the long-term suwari suppression.
查看更多>>摘要：Brine tofu has been in use in China for more than two thousand years now; however, the underlying soymilk coagulation mechanism is not yet clear. In this study, we aimed to systematically investigate the effect of magnesium chloride on the mechanism of tofu preparation using the methods of composition-performance micro-mechanism analysis, combined with droplet experiment and mercury intrusion method. With increasing magnesium chloride concentration, soymilk went through five stages, viz. no coagulation stage (0-3 mmol/L), coagulation formation stage (3-8 mmol/L), coagulation stability stage (8-50 mmol/L), coagulation dissociation stage (50-210 mmol/L), and no coagulation stage again (>= 210 mmol/L). The soymilk follows a trend of diffusion, diffusion/fixation, fixation, growth, and dissolution in the droplets with increasing magnesium chloride concentration. In the coagulation stability stage, the microstructure of tofu (coagulated soymilk) alternated between loose and dense structures. In the coagulation dissociation stage, with increasing magnesium chloride concentration, the sequence of coagulation dissociation was as follows: dissociation of small pores, dissociation of macropores, dissociation of skeletons into clusters, and finally dissociation of clusters. The current study provided theoretical guidance for parameter selection and problem solving in brine tofu production process.
查看更多>>摘要：To improve morphological structure and stability of soy protein isolate chitosan coacervate, a soy protein isolate-chitosan-sodium alginate ternary complex coacervate phase was successfully constructed by adding sodium alginate. The zeta-potential and turbidity data showed that soy protein isolate, sodium alginate, and chitosan interacted with each other in the pH range 5.0-7.0. The highest ternary coacervate yield was obtained at soy protein isolate/sodium alginate ratio 12:1 (g/g), soy protein isolate/sodium alginate:chitosan ratio 4:1 (g/g), pH 6.5, and total biopolymer concentration of 5 g/L. The viscoelastic properties and microstructure were also studied using rheology, fourier transform infrared spectroscopy, texture profile analysis, and scanning electron microscopy, which indicated that the ternary coacervates prepared in pH 5.5, 6.0, and 6.5 had a viscoelastic solid behavior (storage moduli between 12,600 and 35,000 Pa; loss moduli between 3440 and 10,000 Pa) with honeycomb porous network structures. The ternary coacervate prepared at pH 6.5 was more compact and clearly porous. The stability of the ternary complex coacervate phase to pH and ionic strength slight increased. The in situ cross-linking of sodium alginate can improve the structure properties of ternary coacervates, which may provide a new carrier to incoporate bioactive ingredients into food products.
查看更多>>摘要：The influence of alkaline hydrogen peroxide (AHP) treatment of ginseng insoluble dietary fiber (IDF) on physicochemical and functional properties was investigated in this study. The chemical treatment resulted in porous IDF with wrinkled surface and loosened inner structure. Comparing to the unmodified, modifying ginseng IDF increased the water holding capacity (WHC), water swelling capacity (WSC) and oil retention capacity (ORC) by 32.6%, 29.8% and 32.7%, respectively. The chemical modification caused diminution in isoquercetin, ellagic acid, resveratrol, epicatechin and ferulic acid contents and unfavorable decreases in antioxidant activities. AHP treatment improved nitrite-adsorption capacity, cholesterol-adsorption capacity, glucose adsorption capacity and alpha-amylase inhibitory activity. X-ray diffraction and Fourier transform infrared (FT-IR) spectroscopy analyses showed that AHP treatment led to major alterations in the structure of IDF. Thus, AHP modified ginseng IDF, as a novel ingredient could find potential applications in the development of both plant and meat based products.
查看更多>>摘要：Using plant-derived proteins as delivery materials to encapsulate lipophilic bioactive compounds is of great interest. Three protein fractions from brewers' spent grain (BSG) were extracted by the alkaline or alcoholic method with different procedures, and their potential to encapsulate curcumin was evaluated by preparing composite nanoparticles stabilized by lecithin using a pH-cycle method. The three protein fractions showed considerably different encapsulation properties. The particle size and entrapment efficiency varied from 173 to 306 nm and 21.2% to 83.9%, respectively. Compared with the other two fractions, the one extracted with 55% (v/v) ethanol showed better encapsulation performance. Curcumin after encapsulation exhibited an enhanced UV light and thermal stability while its antioxidant activity maintained. These results suggested that BSG protein could be a promising delivery material to encapsulate the water-insoluble bioactive compounds.
查看更多>>摘要：Since microalgae proteins contain the same amount of protein as conventional protein sources such as soybean, milk, beef, and egg, they are considered as new sources of functional amino acids. In this research, microalgae amino acid extracts were studied for their nutritional value as well as their anti-amylase and anti-glucosidase properties, in vitro and in silico. Essential, non-essential, non-protein, flavor, hydrophobic, aromatic, bitter, and sweet amino acids were found to be equal to or greater than those found in egg protein in the selected microalgae. The anti-amylase and anti-glucosidase properties of amino acid extract were confirmed in this study, but at a lower level than acarbose. Microalgae amino acids inhibited amylase and glucosidase by increasing the K-m/V-max ratio through non-competition and un-competition strategy, according to the kinetic analysis. Molecular docking analysis revealed that microalgae amino acids interact with amino acid residues near the active site of amylase and allosteric sites of glucosidase through p-alkyl interactions, positive-negative interactions, salt bridges, and hydrogen bonds. In conclusion microalgae amino acid not only can be considered as functional food with nutritional quality equal to egg protein, but also due to functional amino acid can be imperative as noncompetitive and un-competitive inhibitor of amylase and glucosidase.
查看更多>>摘要：Eggs are the best protein supplements for human beings, which have high nutritional value and are rich in all kinds of essential amino acids. Wild eggs are produced by some rare poultry, considered to have higher nutritional value than ordinary eggs. In this study, black-bone chicken and ring-necked pheasant eggs were selected as samples. Isobaric tags for the relative and absolute quantification labelling techniques (iTRAQ) were used to analyze the protein difference between the two samples. A total of 205 proteins were identified, of which 87 were significantly different. Among those differential proteins, 37 were significantly up-regulated while 50 were significantly down-regulated. Gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that these differentially expressed proteins were closely related to cholesterol metabolism. The expression of some proteins that are adverse to cholesterol metabolism was significantly downregulated in black bone chickens, such as Apolipoprotein B, Apovitellenin-1, Vitellogenin-1 and Vitellogenin-2. Protein interaction analysis showed that there were strong interactions among these proteins. These results indicated that compared with ring-necked pheasant, black-bone chicken eggs have a stronger ability to metabolize cholesterol and are less likely to cause the increase of plasma cholesterol.
查看更多>>摘要：In order to explore the mechanism underlying the ACE inhibitory activity of the active peptides derived from salmon skin in depth, salmon skin collagen peptides (SSCPs) were produced by the hydrolysis of Atlantic salmon (Salmo salar L.) skin and isolated by reverse-phase liquid chromatography. A total of 13 low-molecular-weight peptides were identified by mass spectrometry and used to analyze the inhibitory activity of angiotensin I-converting enzyme (ACE). Three peptides-Gly-Arg, Arg-Glu-Arg, and Gly-Pro-Arg-exhibited the highest ACE inhibitory activities with IC50 values of 0.73 +/- 0.05, 0.89 +/- 0.06, and 1.05 +/- 0.13 mg/mL, respectively. These ACE inhibitory peptides were quantified, and their potential absorption, distribution, metabolism, excretion, and toxicity were predicted in silico together with two previously identified ACE inhibitory dipeptides Ala-Pro and Val-Arg. The molecular mechanism underlying the interaction between the peptides and ACE was determined using in silico methods, including molecular docking, pharmacophore modeling, and pharmacophore heat maps. The five ACE inhibitory peptides exhibited satisfactory absorption, distribution, metabolism, excretion, and toxicity. They formed hydrogen bonds, ionic bonds, metal-receptor bonds, and hydrophobic bonds with ACE to exert ACE inhibitory effects. Hydrogen bonding was the essential factor influencing ACE inhibitory activity.
NSTL
Elsevier