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1.
Food Chem ; 304: 125418, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31479994

RESUMO

Low and high protein dairy powders are prone to caking and sticking and can also be highly insoluble; with powder storage conditions an important factor responsible for such issues. The aim of this study focused on the bulk and surface properties of anhydrous and humidified spray-dried milk protein concentrate (MPC) powders (protein content ~40, 50, 60, 70 or 80%, w/w). Water sorption isotherms, polarized light and scanning electron micrographs showed crystallized lactose in low protein powders at high water activities. High protein systems demonstrated increased bulk diffusion coefficients compared to low protein systems. Glass transition temperatures, α-relaxation temperatures and structural strength significantly decreased with water uptake. CLSM measurements showed that humidified systems have slower real time water diffusion compared to anhydrous systems. Overall, the rate of water diffusion was higher for low protein powders but high protein powders absorbed higher levels of water under high humidity conditions.

2.
Food Chem Toxicol ; 134: 110838, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31568850

RESUMO

The aim of this study was to evaluate the effects of lotus seed oligosaccharides (formulation consisting of LSO2, LSO3-1, LSO3-2 and LSO4; relative ratios are 1.107:0.554:0.183:0.443, m/m/m/m) at dosages of 0.42, 0.83 g/d/kg bw and 2.49 g/d/kg bw on the microbiota composition and the propulsion of intestinal contents in the gut of mice. The results showed that fecal water content increased in treated mice; there was less gut microbiota diversity than in other groups; and there was a large number of fauna in the cecum of the mice. At the same time, the number of short-chain fatty acid (SCFA) bacterial producers increased after feeding with oligosaccharides; Lotus seed oligosaccharides (LOS) also enhanced the concentration of SCFAs in the intestine, which also increased the concentration of cytokines in the serum of mice. In conclusion, these findings suggest that LOS or combination with resistant starch has a better effect on relieving constipation.

3.
Water Res ; 168: 115162, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31629230

RESUMO

Estimating the proportions of particulate organic carbon (POC) endmembers is essential to fully understand the carbon cycle, the function of aquatic ecosystems, and the migration of contaminants in eutrophic lakes. There is currently no effective remote sensing optical algorithm in the literature to solve this problem. In this study, a POC-source color index (SPOC) was constructed based on the terrestrial and endogenous POC ratios calculated from field-measured stable isotope (δ13CPOC) values. The SPOC algorithm traces the sources of POC by utilizing three spectral bands centered approximately at 560 nm, 674 nm, and 709 nm, covering the intrinsic optical information of different POC sources. At the same time, the SPOC algorithm shows good applicability to Ocean and Land Color Instrument (OLCI), Medium-Resolution Imaging Spectrometer (MERIS), Moderate Resolution Imaging Spectroradiometer (MODIS), and Geostationary Ocean Color Imager (GOCI) image data. The POC sources estimated using the algorithm and monthly OLCI data showed that from March 2018 to January 2019, the POC at the surface of Lake Taihu was mainly terrigenous. In addition, due to multiple factors such as algal blooms, plant physiology, river transport, regional rainfall, and carbon cycling, the distribution of POC sources exhibited strong spatial and temporal heterogeneity. Compared with other methods, it is more convenient to use remote sensing to identify the proportion of POC in different endmembers, which offers a more comprehensive understanding of the energy flows and material circulation in lakes.

4.
Ultrason Sonochem ; 59: 104748, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31473418

RESUMO

In this study, a high-intensity ultrasonic field was applied to the electrostatic interactions between soy protein isolate (SPI) and citrus pectin (CP). The emulsifying properties of SPI-CP soluble complexes formed under different ultrasound powers and durations were investigated and peaked at 630 W for 10 min. Micrographs of emulsions revealed that ultrasound-treated complexes generated a more homogeneous emulsion with significantly reduced and uniformly-distributed droplet sizes. To better understand the mechanism for the improved emulsifying properties, the physicochemical and structural properties of the SPI-CP complexes at pH 3.5 with and without ultrasound treatment were investigated. It was revealed that ultrasound increased the absolute values of the zeta potential and surface hydrophobicity of complexes, but significantly decreased their particle sizes, fluorescence intensity and turbidity. Results indicated that cavitation effects resulted in structural modifications in both biomacromolecules, as well as enhanced the electrostatic interactions between SPI and CP, which in combination contributed to the more desirable emulsifying properties of the complex.

5.
Mar Drugs ; 17(9)2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31438457

RESUMO

The phospholipids (PLs) of large yellow croaker (Pseudosciaena crocea, P. crocea) roe contain a high level of polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), which can lower blood lipid levels. In previous research, PLs of P. crocea roe were found able to regulate the accumulation of triglycerides. However, none of these involve the function of DHA-containing phosphatidylcholine (DHA-PC), which is the main component of PLs derived from P. crocea roe. The function by which DHA-PC from P. crocea roe exerts its effects has not yet been clarified. Herein, we used purified DHA-PC and oleic acid (OA) induced HepG2 cells to establish a high-fat model, and the cell activity and intracellular lipid levels were then measured. The mRNA and protein expression of Fatty Acid Synthase (FAS), Carnitine Palmitoyl Transferase 1A (CPT1A) and Peroxisome Proliferator-Activated Receptor α (PPARα) in HepG2 cells were detected via RT-qPCR and western blot as well. It was found that DHA-PC can significantly regulate triglyceride accumulation in HepG2 cells, the effect of which was related to the activation of PPARα receptor activity, upregulation of CPT1A, and downregulation of FAS expression. These results can improve the understanding of the biofunction of hyperlipidemia mediated by DHA-PC from P. crocea roe, as well as provide a theoretical basis for the utilization of DHA-PC from P. crocea roe as a functional food additive.

6.
Appl Microbiol Biotechnol ; 103(18): 7663-7674, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31297555

RESUMO

The inhibitory effect of Bacillomycin D, a cyclic lipopeptide, on Rhizopus stolonifer colonization of cherry tomato was studied, and its possible mechanism of action was explored. Bacillomycin D showed a direct inhibitory effect on R. stolonifer spore germination and mycelial growth in vitro. It conferred both a direct inhibitory effect on R. stolonifer growth in cherry tomato in vivo and induced host resistance in cherry tomato. Moreover, Bacillomycin D treatment significantly increased the activities of plant defense-related enzymes, including chitinase (CHI), ß-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), and peroxidase (POD). Real-time PCR (RT-PCR) showed that defense-related genes involved in the salicylic acid defense signaling pathway and genes encoding pathogenesis-related proteins were up-regulated in Bacillomycin D treatment. Furthermore, Bacillomycin D-C16 resulted in direct inhibition and a remarkable induced resistance to R. stolonifer which was higher than as induced by Bacillomycin D-C14. Together, the data indicated that Bacillomycin D can control the growth of R. stolonifer through both the direct inhibition of the fungus and the activation of defense-related genes and enzymes in cherry tomato.

7.
Int J Biol Macromol ; 137: 554-561, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31229543

RESUMO

To modulate starch digestibility, dry heating combined with annealing treatment was employed to synergistically modulate structure and digestibility of normal maize starch (NMS) and potato starch (PS). Dry heating decreased starch molecular weight and created small molecular fractions with suitable chain length, resulting in starch better rearrangement during annealing treatment. Accordingly, after dry heating combined with annealing treatment starches had the highest pasting temperature, the thinnest and the thickest of crystalline lamellae for NMS and PS, respectively, and the highest ordered structures of cooked-starch compared with single dry heating or annealing modified starches. The results revealed that the synergistic modification altered starch lamellar thickness and increased double helices orders. Thereby, dry heating combined with annealing treated starches exhibited the lowest enzymatic digestibility with increased ca. 7.90% of slowly digestible starch for NMS or elevated ca. 5.04% of resistant starch for PS. The differential changes caused by dry heating combined with annealing treatment between NMS and PS were comprehensively discussed and the difference should result from the different starch crystalline structure and average chain length. This study provides a promising pathway for modulating starch structures and enzymatic digestibility.

8.
Ultrason Sonochem ; 55: 135-148, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30853534

RESUMO

In this paper, a coconut milk composite system (glycerin monostearate as an emulsifier) with different maize additives (e.g., maize kernels and starch with different amylose contents) was treated with high-intensity ultrasound irradiation (HIUS, frequency 20 kHz). The stability and structural features of the added coconut milk emulsion were studied. Comparing the mechanical emulsifications, coconut milk with maize kernels was similar to coconut milk with high-amylose maize starch. However, coconut milk with a high proportion of amylopectin had the best stability. After ultrasonic treatment, the particle sizes were found to be smaller than those in the nonultrasound-treated coconut milk, and the particles demonstrated a monomodal size distribution. The electronegativity of the compound system was significantly improved. The electronegativity of the maize kernel and high-amylose maize starch-coconut milk systems was significantly decreased, and this change was beneficial to the stability of the systems. However, ultrasonic treatment did not change the fluid type of the coconut milk compound system (which showed pseudoplastic fluid characteristics). The proportion of amylose in maize had an important influence on the stability of the compound system. The apparent viscosity and crystallization order of the high-amylose maize starch-coconut milk system were high. However, the waxy maize starch system showed high complex viscosity and tended to be liquid with ultrasonic treatment. Ultrasound treatment reduced the particle size of coconut milk and homogenized the distribution of the system. Additionally, the amylase of the system contained amylose encapsulated in the interfacial layer after ultrasound treatment. The tiny gel beads formed by waxy maize starch had a good fusion effect on coconut milk fat/protein droplets. The results indicated that the stability of coconut-grain milk composite systems can be enhanced with the use of maize additives and ultrasound irradiation through space effects, electrostatic effects and continuous phase viscosity.


Assuntos
Amilose/química , Cocos/química , Sonicação , Zea mays/química , Cor , Tamanho da Partícula , Reologia , Tensão Superficial , Viscosidade
9.
Crit Rev Food Sci Nutr ; : 1-16, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30892058

RESUMO

Gels are viscoelastic systems built up with a liquid phase entrapped in a three-dimensional network, which can behave as carriers for bioactive food ingredients. Many attempts have been made to design gel structures in the water phase (hydrogels, emulsion gels, bigels) or oil phase (organogels, bigels) in order to improve their delivery performances. Hydrogels are originated from proteins or polysaccharides, which are suitable for the delivery of hydrophilic ingredients. Organogels are mainly built up with the self-assembling of gelator molecules in the oil phase, and they offer good carriers for lipophilic ingredients. Emulsion gels and bigels, containing both aqueous and oil domains, can provide accommodations for lipophilic and hydrophilic ingredients simultaneously. Gel structures (e.g. rheology, texture, water holding capacity, swelling ratio) can be modulated by choosing different gelators, modifying gelation techniques, and the involvement of other ingredients (e.g. oils, emulsifiers, minerals, acids), which then alter the diffusion and release of the bioactive ingredients incorporated. Various studies have proved that gel-based delivery systems are able to improve the stability and bioavailability of many bioactive food ingredients. This review provides a state-to-art overview of different gel-based delivery systems, highlighting the significance of structure-functionality relationship, to provide advanced knowledge for the design of novel functional foods.

10.
J Food Sci ; 84(1): 165-173, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30569533

RESUMO

This study aimed to investigate the antidiabetic activity of water-ethanol extract of green macroalgae Enteromorpha prolifera (EPW) and its flavonoid-rich fraction less than 3 kDa (EPW3) in type 2 diabetic mice induced by streptozotocin and a high-sucrose/high-fat diet. The major active compounds were identified using ultra-performance liquid chromatography coupled with quadrupole-time-of-flight-tandem mass spectrometry. Quantitative gene expression analysis of the insulin signaling pathway was performed. The effects of EPW3 on gut microflora in diabetic mice were analyzed by high-throughput 16S rRNA gene sequencing. The results showed EPW3 treatment decreased the fasting blood glucose, improved oral glucose tolerance, and protected against liver and kidney injury with reduced inflammation in diabetic mice. The active principle of EPW3 revealed hypoglycemic effect as indicated by activation of the IRS1/PI3K/AKT and inhibition of the JNK1/2 insulin pathway in liver. Furthermore, the treatment significantly enriched the abundance of Lachnospiraceae and Alisties, which were positive correlation of metabolic phenotypes. These findings indicated that EPW3 possessed great therapeutic potential as adjuvant therapy for type 2 diabetes.


Assuntos
Microbioma Gastrointestinal/efeitos dos fármacos , Hipoglicemiantes/farmacologia , Extratos Vegetais/farmacologia , Alga Marinha/química , Ulva/química , Animais , Bacteroidetes/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/etiologia , Firmicutes/metabolismo , Flavonoides/farmacologia , Teste de Tolerância a Glucose , Insulina/sangue , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Proteobactérias/metabolismo , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/isolamento & purificação , Transdução de Sinais
11.
J Dairy Res ; 85(3): 366-374, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30088465

RESUMO

This Review describes the objectives and methodology of the DairyWater project as it aims to aid the Irish dairy processing industry in achieving sustainability as it expands. With the abolition of European milk quotas in March 2015, the Republic of Ireland saw a surge in milk production. The DairyWater project was established in anticipation of this expansion of the Irish dairy sector in order to develop innovative solutions for the efficient management of water consumption, wastewater treatment and the resulting energy use within the country's dairy processing industry. Therefore, the project can be divided into three main thematic areas: dairy wastewater treatment technologies and microbial analysis, water re-use and rainwater harvesting and environmental assessment. In order to ensure the project remains as relevant as possible to the industry, a project advisory board containing key industry stakeholders has been established. To date, a number of large scale studies, using data obtained directly from the Irish dairy industry, have been performed. Additionally, pilot-scale wastewater treatment (intermittently aerated sequencing batch reactor) and tertiary treatment (flow-through pulsed ultraviolet system) technologies have been demonstrated within the project. Further details on selected aspects of the project are discussed in greater detail in the subsequent cluster of research communications.


Assuntos
Conservação dos Recursos Naturais/métodos , Laticínios , Indústria de Processamento de Alimentos/métodos , Animais , Indústria de Laticínios/métodos , Meio Ambiente , Irlanda , Chuva , Águas Residuárias/química , Águas Residuárias/microbiologia , Purificação da Água/métodos
12.
Front Microbiol ; 9: 1186, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29963017

RESUMO

There is a growing recognition of the role the gastrointestinal microbiota plays in health and disease. Ingested antimicrobial proteins and peptides have the potential to alter the gastrointestinal microbiota; particularly if protected from digestion. Nisin is an antimicrobial peptide that is used as a food preservative. This study examined the ability of nisin to affect the murine microbiota when fed to mice in two different starch based matrices; a starch dough comprising raw starch granules and a starch gel comprising starch that was gelatinized and retrograded. The effects of the two starch matrices by themselves on the microbiota were also examined. Following 16S rRNA compositional sequencing, beta diversity analysis highlighted a significant difference (p = 0.001, n = 10) in the murine microbiota between the four diet groups. The differences between the two nisin containing diets were mainly attributable to differences in the nisin release from the starch matrices while the differences between the carriers were mainly attributable to the type of resistant starch they possessed. Indeed, the differences in the relative abundance of several genera in the mice consuming the starch dough and starch gel diets, in particular Akkermansia, the relative abundance of which was 0.5 and 11.9%, respectively (p = 0.0002, n = 10), points to the potential value of resistance starch as a modulator of beneficial gut microbes. Intact nisin and nisin digestion products (in particular nisin fragment 22-31) were detected in the feces and the nisin was biologically active. However, despite a three-fold greater consumption of nisin in the group fed the nisin in starch dough diet, twice as much nisin was detected in the feces of the group which consumed the nisin in starch gel diet. In addition, the relative abundance of three times as many genera from the lower gastrointestinal tract (GIT) were significantly different (p < 0.001, n = 10) to the control for the group fed the nisin in starch gel diet, implying that the starch gel afforded a degree of protection from digestion to the nisin entrapped within it.

13.
Huan Jing Ke Xue ; 39(1): 57-67, 2018 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965666

RESUMO

The identification of urban black-odor water bodies plays an important role in monitoring and controlling black-odor water bodies. In 2016, a ground survey was conducted on the urban reach of Nanjing, and 55 samples from the West Shazhou River, Tuwei River, Xuanwu Lake, and Jinchuan River were obtained. The spectral characteristics of urban black-odor water bodies and other water bodies were analyzed. Recognition algorithms for GF-2 data were proposed in order to analyze the spatial distribution and environmental factors of urban black-odor water bodies. These algorithms were single-band thresholds based on reflectance of the green band, the difference between the blue band and green band, the ratio of the green band and red band, and the chromaticity value. The results indicate that:① compared with other types of water, the urban black-odor water has the smallest spectral slope in the range of 400-500 nm and lowest reflectivity, and the peaks and valleys are not prominent in the whole visible range; ② based on the verification, the accuracy of the ratio algorithm is the highest; and ③ using the ratio algorithm to calculate the GF-2 data of November 3, 2016, a total of 11 black river sections are identified. The entire length is 40.7 km, and the area is 0.749 km2.The black-odor water sections are distributed over a wide range but are not continuous, and they are concentrated in the densely populated areas. Domestic sewage, industrial waste water, and broken river channel are the main reasons.

14.
Food Chem ; 264: 172-179, 2018 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-29853363

RESUMO

An innovative approach of high hydrostatic pressure was used to prepare lotus seed amylose-fatty acid complexes. The objective of this study was to investigate their structure and thermal properties. WAXD pattern of amylose changed from B-type to B- and V6-type hybrid polymorphs, and its relative crystallinity increased upon the addition of fatty acids. Carboxyl group observed by FTIR indicates the formation of complexes. SAXS was performed to measure the lamellar structure of complexes. The complexes were more compact and had lower amounts of amorphous regions compared with amylose controls. Entrapped fatty acids, higher melting temperature, and enthalpy change of complexes but not of the controls were detected by DSC. The distribution of fatty acid molecules in the complex matrix was estimated through NMR. Under different pressures, the complexes exhibited dissimilar characteristics with the increase in aliphatic chain length, as observed by WAXD, FTIR, DSC and NMR.


Assuntos
Amilose/química , Ácidos Graxos/química , Cristalização , Temperatura Alta , Pressão Hidrostática , Lotus/química , Espectroscopia de Ressonância Magnética , Espalhamento a Baixo Ângulo , Sementes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
15.
Food Res Int ; 103: 1-7, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29389594

RESUMO

Emulsion filled protein (EFP) gels were prepared through a cold-set gelation process using denatured protein, and the effects of fat substitutes on the texture and volatile release of EFP gels were investigated. Pre-heating determined the denature degree of protein structure, and higher heating intensity resulted in higher viscosity of the emulsions, and larger storage modulus (G') of the corresponding gels. Oil-reduced EFP gels (15% sunflower oil) were prepared with the addition of fat substitutes (medium chain triglyceride-MCT, maltodextrin, or guar gum), and they showed different properties from the full-oil counterpart (20% sunflower oil). The three tested fat substitutes were effective in enhancing G' and stiffness of the gels, while the magnitude was dependent on the content and types of fat substitutes. The increase in the content of MCT or maltodextrin (5-15%) could lead to earlier onset of gelation, but the presence of fat substitutes did not affect the water holding capacities of the gels. With strengthened gel structures by the fat substitutes, oil-reduced gels could have decreased air-gel partition coefficients of the volatiles, particularly the more lipophilic compounds. Among the three fat substitutes, MCT and maltodextrin were more capable to retain volatiles in the gels.

16.
Food Res Int ; 103: 380-389, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29389627

RESUMO

Starch-lipid complexes were prepared using lotus seed starch (LS) and glycerin monostearate (GMS) via a high-pressure homogenization (HPH) process, and the effect of HPH on the paste structure and rheological properties of LS-GMS was investigated. Rapid Visco Analyser (RVA) profiles showed that HPH treatment inhibited the formation of the second viscosity peak of the LS-GMS paste, and the extent of this change was dependent on the level of homogenized pressure. Analysis of the size-exclusion chromatography, light microscopy, and low-field 1H nuclear magnetic resonance results revealed that high homogenized pressure (70-100MPa) decreased molecular weight and size by degrading the branch structure of amylopectin; however, intact LS-GMS granules can optimize the network structure by filler-matrix interaction, which causes free water to transition into immobile water in the starch paste. The steady-shear results showed that the LS-GMS pastes presented non-Newtonian shear-thinning behavior, with higher homogenized pressure producing a smaller hysteresis loop area. During the oscillation process, the LS-GMS pastes prepared at 100MPa exhibited the lowest loss tangent values in all the complexes, indicating a stronger resistance to vibration.

17.
Food Chem ; 252: 115-125, 2018 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-29478521

RESUMO

Starch-lipid complexes were prepared using lotus seed starch (LS) and glycerin monostearate (GMS) via a high-pressure homogenization process, and the effect of high pressure homogenization (HPH) on the slow digestion properties of LS-GMS was investigated. The digestion profiles showed HPH treatment reduced the digestive rate of LS-GMS, and the extent of this change was dependent on homogenized pressure. Scanning electron microscopy displayed HPH treatment change the morphology of LS-GMS, with high pressure producing more compact block-shape structure to resist enzyme digestion. The results of Gel-permeation chromatography and Small-angle X-ray scattering revealed high homogenization pressure impacted molecular weight distribution and semi-crystalline region of complexes, resulting in the formation of new semi-crystalline with repeat unit distance of 16-18 nm and molecular weight distribution of 2.50-2.80 × 105 Da, which displayed strong enzymatic resistance. Differential scanning calorimeter results revealed new semi-crystalline lamellar may originate from type-II complexes that exhibited a high transition temperature.


Assuntos
Digestão , Glicerídeos/química , Lotus/química , Pressão , Sementes/química , Amido/química , Amido/metabolismo , Peso Molecular
18.
J Dairy Sci ; 101(3): 1901-1914, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29274957

RESUMO

Bacteriophage infection is a large factor in dairy industrial production failure on the basis of pure inoculation fermentation, and developing good commercial starter cultures from wild dairy products and improving the environmental vigor of starter cultures by enhancing their phage resistance are still the most effective solutions. Here we used a spontaneous isolation method to obtain bacteriophage-resistant mutants of Lactobacillus delbrueckii ssp. bulgaricus strains that are used in traditional Chinese fermented dairy products. We analyzed their phenotypes, fermentation characteristics, and resistance mechanisms. The results showed that bacteriophage-insensitive mutants (BIM) BIM8 and BIM12 had high bacteriophage resistance while exhibiting fermentation and coagulation attributes that were as satisfying as those of their respective parent strains KLDS1.1016 and KLDS1.1028. According to the attachment receptor detection, mutants BIM8 and BIM12 exhibited reduced absorption to bacteriophage phiLdb compared with their respective bacteriophage-sensitive parent strains because of changes to the polysaccharides or teichoic acids connected to their peptidoglycan layer. Additionally, genes, including HSDR, HSDM, and HSDS, encoding 3 subunits of a type I restriction-modification system were identified in their respective parent strains. We also discovered that HSDR and HSDM were highly conserved but that HSDS was variable because it is responsible for the DNA specificity of the complex. The late lysis that occurred only in strain KLDS1.1016 and not in strain KLDS1.1028 suggests that the former and its mutant BIM8 also may have an activatable restriction-modification mechanism. We conclude that the L. bulgaricus BIM8 and BIM12 mutants have great potential in the dairy industry as starter cultures, and their phage-resistance mechanism was effective mainly due to the adsorption interference and restriction-modification system.


Assuntos
Bacteriófagos , Produtos Fermentados do Leite/microbiologia , Lactobacillus delbrueckii/genética , Lactobacillus delbrueckii/virologia , Fermentação , Lactobacillus delbrueckii/isolamento & purificação , Lactobacillus delbrueckii/metabolismo , Mutação , Fenótipo
19.
Nanomaterials (Basel) ; 7(12)2017 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-29257116

RESUMO

The attractive potential of natural superoxide dismutase (SOD) in the fields of medicine and functional food is limited by its short half-life in circulation and poor permeability across the cell membrane. The nanoparticle form of SOD might overcome these limitations. However, most preparative methods have disadvantages, such as complicated operation, a variety of reagents-some of them even highly toxic-and low encapsulation efficiency or low release rate. The aim of this study is to present a simple and green approach for the preparation of SOD nanoparticles (NPs) by means of co-incubation of Cu/Zn SOD with glucose. This method was designed to prepare nanoscale aggregates based on the possible inhibitory effect of Maillard reaction on heating-induced aggregation during the co-incubation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results indicated that the Maillard reaction occurred during the co-incubation process. It was found that enzymatically active NPs of Cu/Zn SOD were simultaneously generated during the reaction, with an average particle size of 175.86 ± 0.71 nm, and a Zeta potential of -17.27 ± 0.59 mV, as established by the measurement of enzymatic activity, observations using field emission scanning electron microscope, and analysis of dynamic light scattering, respectively. The preparative conditions for the SOD NPs were optimized by response surface design to increase SOD activity 20.43 fold. These SOD NPs showed storage stability for 25 days and better cell uptake efficacy than natural SOD. Therefore, these NPs of SOD are expected to be a potential drug candidate or functional food factor. To our knowledge, this is the first report on the preparation of nanoparticles possessing the bioactivity of the graft component protein, using the simple and green approach of co-incubation with glucose, which occurs frequently in the food industry during thermal processing.

20.
J Food Sci ; 82(9): 2105-2112, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28858389

RESUMO

Lactose-sugars systems were produced by spray drying. They were lactose, lactose-glucose (4:1) mixtures, lactose-maltose (4:1) mixtures, lactose-sucrose (4:1) mixtures, lactose-trehalose (4:1) mixtures, and lactose-corn syrup solids (CSS) (4:1) mixtures. The physical characteristics, water sorption behavior, glass transition, and mechanical properties of miscible lactose-sugars systems were investigated. Lactose-glucose mixtures had larger particle size than other lactose-sugars systems after spray drying. The presence of glucose or sucrose in lactose-sugars mixtures decreased the glass transition temperatures of amorphous systems, while the presence of maltose and trehalose had only minor impact on the glass transition temperatures. Moreover, glucose accelerated the crystallization of amorphous system at 0.44 aw , but its presence delayed the loss of sorbed water at higher water activities (≥0.54 aw ). Mechanical property study indicated that glucose and sucrose in amorphous system could result in an increase of molecular mobility, while the presence of CSS could decrease the free volume and maintain the stiffness of the miscible systems.


Assuntos
Lactose/química , Açúcares/química , Fenômenos Biomecânicos , Cristalização , Dessecação , Temperatura de Transição
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