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1.
Goat milk ice cream was made with various sources of fat ingredients such as cream, soybean oil, rice bran oil and butter with the purpose of seeking the fat ingredient source instead of fat source from cow origin. The physical properties and the sensory evaluation of ice cream were then investigated. The firmness of goat milk ice cream mixed with rice bran oil, butter and cream were not significantly different before aging at 4 ℃ for 8 h. All of them gave the overrun between 51%-63% and the one with butter was the highest. The meltdown rate of all types of fat ingredients are not significantly different, being in the range of 0.86-0.88 g/min. According to sensory evaluation, the cow milk ice cream with cream was mostly accepted in all attributes such as appearance, smoothness, whiteness, melting in mouth and odor while the goat milk with cream and butter are the second and third. Nevertheless, the goat milk ice cream with soybean oil and rice bran oil were moderately accepted in overall preferences.  相似文献   

2.
In recent years, research on biopolymer based-coating containing natural antimicrobial agents is developing significantly. The objective of this study was to evaluate the antimicrobial efficiency of six formulations containing pre-selected natural antimicrobial compounds against Listeria monocytogenes, Escherichia coli O 157:H7, Salmonella typhimurium, the total bacteria and total yeasts and molds in cauliflower. Each formulation was subjected to a sensory test in parallel to microbiological analysis and the efficiency during storage at 5 ℃ was evaluated for the two best formulations, based on their ability to eliminate the target microorganisms. Both formulations were able to reduce all pathogens and total flora below detectable levels after 24 h of storage at 5 ℃. Using washing or spraying treatments, the two formulations were able to reduce Listeria to undetectable levels for 3 d. This efficiency was extended to 7 d when the formulations were incorporated into an edible coating. Washing treatment with the two formulations was also able to limit the growth of yeast and molds at levels lower than 2 log, for more than 7 d. The population of E. coli was reduced to below the detection limit during 14 d of storage, after washing treatment with the two formulations. The spraying treatment of cauliflower with the formulations allowed the use of very small amounts of antimicrobials while maintaining a fairly good efficiency, greatly reducing the potential costs of implementing this method in the industry. Future research may focus on development of nanoemulsion of antimicrobial formulations based on the developed antimicrobial formulations in this study to improve the better coating efficiency.  相似文献   

3.
The ingestion of probiotic lactic acid bacteria has been evaluated and noted that it has an effect on the balance of desirable microbiota in the gastrointestinal tract. Lactobacillus gasseri demonstrates good survival in the gastrointestinal tract, and it has been associated with a variety of probiotic activities and roles, including the reduction of fecal mutagenic enzymes, the production of bacteriocins and the stimulation of macrophages immunomodulation. The aim of the study was to evaluate the effects of a pool of L. gasseri strains isolated from the feces of breastfed infants added in the human milk of healthy women. The milk was both pasteurized and unpasteurized, to verify the cell cytotoxicity of macrophages and to quantify the production of immunologic mediators such as IL-4, IL-6, IFN-γ, TNF-α, NO and oxygen intermediary compounds (H2O2). The administration of raw human milk and pasteurized human milk to infants is a regular, encouraged practice in units of intensive therapy (UITs) and our present investigation verified the beneficial effect of addition of a pool of L. gasseri to pasteurized human milk (PHML). Our results show that probiotic supplementation helped to maintain cell viability, reduced IL-6 and IFN-γ production and stimulated TNF-α, NO, H2O2, IL-4 production. Nevertheless, the results indicate that the addition of lactobacillus to human milk was not a determinant in the production of TNF-α. L. gasseri added to breast milk did not present a cytotoxic risk, and the addition ofL. gasseri to pasteurized milk of human milk bank would benefit newborns that depend on milk banks for the colonization of more desirable microbiota.  相似文献   

4.
Food crops (bush mango (n=12), roasted cashew nut (n=12), dried okra (n=12), sesame (n=35) and sorghum (n=36)) sold in markets in Nasarawa state, Nigeria, were analyzed using a LC-MS/MS mycotoxin method. The hepatocarcinogenic aflatoxin B1 was detected in 42%, 25% and 19% of bush mango, dried okra and sorghum samples at mean concentrations of 19.2 µg/kg, 8.27 µg/kg and 4.75 µg/kg, respectively, while fumonisin B1 contaminated 9% of the sesame (mean: 12.5 µg/kg) and 47% of the sorghum (mean: 461 µg/kg) samples. At least 19% of the sorghum samples were co- contaminated with aflatoxin B1 and fumonisin B1. The nephrotoxic ochratoxin A was detected in bush mango, sorghum and, for the first time to the best of our knowledge, in dried okra. These vended food crops in the local markets are therefore prone to mycotoxin contamination, which may pose a health threat to consumers, and require intentional mitigation efforts.  相似文献   

5.
6.
The effect of reduced glutathione (GSH) on fresh and pre-proofed frozen dough rheological properties were investigated using dynamic stress rheometry and small scale extensibility with the addition of three levels (80×10^-6, 160 ×10^-6 and 240× 10^-6 GSH) and six storage times (0 and 1 day, 2, 4, 6 and 8 weeks). Three relaxation times (1, 13 and 26min) after loading the dough in the rheometer were used to determine storage (G') and loss (G") moduli. Correlations for G' (r=-0.678 and 0.622 at 0.05, and 10Hz, respectively) and G" (r=0.699, and 0.690 at 0.05, and 10Hz, respectively) were observed with the area under the extension curve at 26 min relaxation time. The addition of GSH to fresh dough reduced G' (16.4% to 55.9%) and G" (13.7% to 52.2%). Freezing and frozen storage caused increase in G' and G". The addition of GSH reduced dough strength indicated by the reduction in maximum resistance to extension (Rmax) and the ratio of maximum resistance to extensibility(Rmax/E). The reduction in Rmax across all relaxation times ranged from 16.2% to 59.4%. An increase in dough extension (E) was observed with 240 ×10^-6 GSH at all frozen storage and rest period times. Addition of GSH caused an increase of liquid phase (30.6% to 35.3%) in fresh dough and frozen dough (10.3% to 20.7%) after one day frozen storage. Negative correlations of water content in the solid phase with dough extensibility and area under the extensibility curve were found (r=-0.594 and -0.563, respectively, p 〈 0.001). This suggests a loss of dough extensibility and strength as the water holding capacity of the dough components changes during frozen storage.  相似文献   

7.
A large number of wound dressings are currently used in the treatment of burns chronic ulcers etc. An ideal wound dressing should prevent dehydration of the wound and retain a favorable moist environment at the wound interface. It should have good antibacterial properties and be easily removed without trauma too. Wound dressings are generally made of readily available bio-materials that require minimal processing possess nontoxic non-allergenic and antimicrobial properties as well as promote wound healing. Clinically collagen chitin chitosan etc. are usually used as materials for producing wound dressings as these materials are capable of accelerating the healing processes at molecular cellular and individual levels. Tussah silk fibroin bombyx mori sericin and gelatin non-toxic and extensive have good bio-compatibility degradability and film-forming properties which are conducive to cell adhesion. In order to prepare safe biofilms with excellent antibacterial properties we prepared a kind of bombyx mori sericin / tussah silk fibroin / gelatin BS-TSF-GEL blended film by using tussah silk fibroin bombyx mori sericin and gelatin as bio-based materials and polyethylene glycol 200 as the cross-linking agent. Firstly we designed the single factor experiment and orthogonal experiment to optimize the preparation process of the BS-TF-GEL blended film. On this basis the blended film was modified with ethanol of different concentrations to improve its strength and crystallinity. The structure and properties of the blended film were characterized by measuring the dissolution loss rate tensile properties microscopic morphology and crystal structure. Finally antimicrobial peptides were loaded by adsorption to obtain the BS-TSF-GEL antimicrobial film. The results showed that the ratio of the optimum formula for the (BS-TSF-GEL) blended film required a mixture of bombyx mori sericin (4. 50 μg / mL) and tussah silk fibroin (27. 5 mg / mL) with a volume ratio of 2:1 polyethylene glycol 200 and gelatin solution (360 mg / mL) which accounted for 35% 40% and 25% respectively of the total system. The dissolution loss rate of the BS-TSF-GEL blended film was 34. 62% the elongation at break was 34. 15% and the breaking strength was 578. 8 kPa after being treated with anhydrous ethanol. FTIR and X-ray diffraction results showed that Silk Ⅱ dominated the BS-TSF-GEL blended film while Silk Ⅰ was in a small amount. The BS-TSF-GEL blended film was pale yellow and porous on the surface which was the ideal material for loading antimicrobial peptides. The BS-TSF-GEL blended film loaded with antimicrobial peptides had a good inhibitory effect on both Escherichia coli and Staphylococcus aureus. It is expected to be used in the field of disposable biomedical materials such as wound dressings. In this study three natural materials with unique advantages were selected as substrates for biofilms and polyethylene glycol with high bio-safety was used as the cross-linking agent to enhance the application value of the blended film by loading antimicrobial peptides. The results broaden the application field of silkworm silk and provide a new way for the development and exploitation of silk fibroin in biological dressings and other medical bio-materials. Bombyx mori sericin tussah silk fibroin and gelatin have been widely used in biological tissue engineering as natural biological materials. In this study three natural materials were used as the biofilm substrate to successfully prepare excellent-performance BS-TSF-GEL blend film using polyethylene glycol cross-linking and ethanol post-treatment techniques. Moreover specific properties can be conferred by replacing different loading substances such as antimicrobial biofilm carrying antimicrobial peptides and biofilm sustained release carrier loading drugs. In addition 3D printing electrostatic spinning and other technologies can also be used to shape the BS-TSF-GEL into different shapes to meet the application requirements under different conditions. In conclusion the research results explore a new way for the application of silk protein. © 2022 Authors. All rights reserved.  相似文献   

8.
The silk fiber has an irreplaceable position in textile fibers and related silk fabrics have the advantages of light and airy texture good moisture absorption and breathability comfort in wear etc. It is also widely used in other fields such as the biomedical sector. However silk also has its own limitations poor light resistance and susceptibility to ultraviolet light especially the ultraviolet light of 290-400 nm wavelength in daylight such as under which condition it is prone to yellowing and photodegradation. The yellowing of silk is due to the photo-oxidation of tyrosine and tryptophan in silk protein under the action of ultraviolet light from sunlight and due to the production of yellow substances which affects the whiteness of silk. In addition from the molecular structure of silk most of the amino acids susceptible to UV light are distributed in the amorphous region. As the amorphous region is affected the structure of the crystalline region is also gradually relaxed the local degradation begins and the silk protein macromolecule chain is cleaved which leads to the decrease of the mechanical properties of silk fibers and accelerates the aging of silk fibers and fabrics. Therefore it is necessary to modify the silk products outside the anti-purple line. The current methods used to modify silk are mostly for post finishing modification including coating impregnation and chemical grafting methods but these methods often affect the original color or feel of the fabric and the durability of the modified effect is also poor. The feeding method is a green method to obtain modified silk by spraying mulberry leaves or artificial feed mixed with modifier which is ingested by silkworm and transferred to silk gland. In this study five aminobenzene UV absorbers were used as exogenous additive food for silkworms. The effect of molecular polarity on the transport of modifiers to silk glands was investigated and their effects on silkworm development and silk structural properties were studied. It was found that the aminobenzene UV absorbers were more easily transferred to the central silk gland silk glue and less to the posterior silk gland (fibroin). 4-dimethylaminobenzoic acid was found to be the highest in the posterior silk gland with a content of 3. 27 μg / strip. The cocoon width and cocoon quality of this group were significantly lower than those of the control group and the silk gum content was increased when this group was used as the study object. Compared with the control group the relative content of β-folded structure and crystallinity of the silk in the addition feeding group decreased slightly. The silkworm silk in the feeding group showed a certain UV absorption ability. After 330 h UV irradiation the breaking strength and elongation of the control group decreased by 48. 95% and 43. 52% respectively while those of the feeding group decreased by 42. 03% and 34. 18% respectively. In this paper UV absorbers were added to silkworms to obtain modified silk mainly focusing on the transfer of the modifier to the silk gland and the structural properties of the modified silk only for the most UV absorbers to enter the silk gland of the posterior group of silk. Other properties of the modified silk such as washing resistance have not been studied and some more in-depth studies are required. For instance it needs to be studied in depth for the limited absorption of exogenous additives by silkworms additive food's being not always absorbed by silkworms and transferred to the silk gland and the mechanism of action between the additive food and silk protein after the former's entering the silk gland. © 2022 Authors. All rights reserved.  相似文献   

9.
A uniform and effective heat distribution inside the canned milk is very crucial for achieving effective sterilization. It is extremely difficult to establish the temperature profile inside the canned milk during continuous industrial scale operation. Computational fluid dynamics (CFD) simulation can be a useful tool to determine the temperature distribution of the fluid inside the can during the sterilization process. A CFD model was developed for the sterilization of canned milk at 121 ~C. The simulation results were validated with the experimental measurements of temperatures. The formation and movement of slowest heating zone (SHZ) during the sterilization process was tracked. Moreover, effect of can position (vertical and horizontal) during processing on milk temperature distribution inside the can was also investigated. Higher Grashof and Rayleigh numbers were obtained for vertical positioning of can compared to horizontal can processing. Further, effectiveness of the process was calculated based on F-value and these results reinforced the positive effect of horizontal position of can during the sterilization process.  相似文献   

10.
Nitrate is closely related to the content of nitrosamine,which is known to be toxic and is determined in aquatic products.In this paper,a new sensitive UV spectrophotometry method based on K-model for rapid determination of nitrate in different kinds of samples was developed.The UV characteristic absorbance points of nitrate were selected and optimized.Under the optimized experimental conditions the calibration equation and K-model were obtained.The calibration curve is linear in the concentration range of 1 to 100μg/ml(R2=0.9973).This method was found to exhibit good accuracy,precision and repeatability.The developed method could be applied to the determination of nitrate in aquatic products and other food products.  相似文献   

11.
Aspergillus flavus maize colonization leads to crop contamination by toxic secondary metabolites and carcinogens called aflatoxins (AF); it has negative effects in public health and has caused economic losses in agricultural activities. Eleven genotypes of immature maize grain frequently used in Mexico were inoculated in vitro with two indigenous toxigenic strains ofA. flavus. The size of inoculum, temperature, humidity and presence of other phytopathogens were assessed. Genotypes Popcorn, C-526, Garst 8366, As910 and 30G40 showed resistance to rating of fungal colonization (FC) and AF accumulation, while 3002W, 30R39, Creole, C-922, HV313 and P3028W genotypes were less resistant. AFB~ had the highest concentrations (26.1 mg/kg ± 14.7 mg/kg), while AFB2, AFG1 and AFG2 showed only residual concentrations 1.6, 2.0 and 4.0 ~tg/kg, respectively. Concerning FC and AF, there were significant differences (P 〈 0.01) between strains and genotype. Both strains showed significant association (P 〈 0.01) between FC and the concentrations of AFB1 and AFB2 (R2: 99.5% and 93.2%; 87.2% and 73.2%, respectively). Results suggest that the level of resistance to fungus infection and AF accumulation is related to maize genotype. It emphasizes the relevance of developing A. flavus resistant maize genotypes as an alternative to control contamination in foodstuff intended for human and animal consumption.  相似文献   

12.
Soy yogurt has gained significant popularity due to its nutritional health benefits. The objectives of this study were to develop flavored yogurt from soybean milk with reduced soy aftertaste by the addition of 30% (wt/wt) strawberry or orange jam in conjunction with a lactic acid fermentation. Soy milk-based yogurt products were assessed for microbial quality and for acceptability by a panel of Jordanian and Malaysian consumers. Sixty-one individuals, of whom 75.4% (n = 46) were Jordanian and 24.6% (n = 15) were Malaysian, evaluated the plain and flavored soy milk-based yogurt. The overall acceptability of orange and strawberry soy yogurt was rated significantly higher than plain soy yogurt. In general, the orange and strawberry soy yogurt received higher sensory ratings from Malaysian than Jordanian consumers. In addition, formulations with orange jam received higher scores than those flavored with strawberry. Shelf life tests showed that soy yogurt was acceptable for at least 8 d without perceptible spoilage. Therefore, the approach used yielded flavored products with better acceptability and improved sensory attributes, including decreased intensity of off flavor, with suitable shelf life at 4 ℃.  相似文献   

13.
Introduction Milk is a raw material used in the fabrication of a very large range of products. The modalities of payment are designed to orientate milk production according to technological needs and hygiene and food security requirements. The processors seek milk witch is adapted for all types of processing ( Beguin, 1994 ).  相似文献   

14.
Hydroxypropyl celluloses (HPC) were homogenously synthesized by the reaction of cellulose with propylene oxide in NaOH/urea aqueous solution.Water-soluble HPC with molar degree of substitution (MSNMR) in the range of 0.52~ 0.78 was prepared from microcrystalline cellulose,cotton linters,and spruce sulfite pulp.The structure of the HPC samples was characterized by means of FT-IR,NMR,gas chromatography (GC),and size exclusion chromatography (SEC) analyses.Three types of cellulose samples with different molecular weights were found to dissolve well in the NaOH/urea solvent with no obvious differences in reactivity and regioselectivity.The relative reactivity of hydroxyl groups in the glycosyl unit was in the following order:O-6 > O-2 >O-3.In addition,the results of the study indicated that the tandem reaction during hydroxypropylation could be ignored.  相似文献   

15.
16.
The resistance of wood-fiber paper to water, grease, and water vapor is usually attained by immersing the base paper in hydrophobic oil, laminating with a plastic or metal film, or the application of a barrier coating. Oil impregnation and the addition of films may make the paper difficult to recycle or persistent in the environment owing to their strong binding force and nondegradability. Environmental concerns have attracted worldwide attention to eco-friendly barrier coatings. In this study, degradable polyvinyl alcohol(PVA) and kaolin clay pigment were used to prepare coatings that were applied to a base paper. By measuring the barrier properties of the coated paper, including the water absorptiveness(Cobb60 value), Hercules sizing degree, oil resistance(Kit rating), and water vapor transmission rate(WVTR), an optimal coating formulation and process were proposed. To examine the barrier mechanism of the PVA/kaolin clay coating, we characterized the coating microstructures using a scanning electron microscopy(SEM) and a mercury porosimeter. The results showed that the Cobb60 value and water vapor transmission rate of the coated paper decreased by 61.4% and 98.6%, respectively, compared with the base paper, for a pre-coating weight of 0.98 g/m~2 and a top-coating weight of about 3.23 g/m~2. Furthermore, the Hercules sizing degree rose by a factor of 337.2, while the oil resistance(Kit rating) increased from 0 to 12. The optimum drying temperature for a wet coating layer was found to be 170℃, and the optimum weight ratio of PVA to kaolin clay in the coating was determined to be 50∶50. It was assumed that the PVA/kaolin clay coating improved the smoothness of the paper considerably and decreased the pore size by filling the pores on the paper surface and forming an even film, thus enhancing the paper barrier performance. The coated paper also exhibited good repulpability.  相似文献   

17.
Antimicrobial treatments of textiles, especially cotton and synthetic fibres, have attracted considerable attention in research and manufacturing. The treatments prevent odour formation and fabric deterioration that arise from the growth of microbes on the textiles during their use or storage. However, wool is more difficult to treat due to its unique surface properties. In this report,we demonstrate that the pretreated wool was also able to exhaust up to 10% ( owf ) (on weight of fabric) of benzalkonium chloride,a cationic quaternary ammonium salt with biocidal activity. The exhaustion on the pretreated wool did not vary between 20 °C and 60 °C and was slightly affected by acidic pH value. Wool fabrics finished with 6% (owf) or more benzalkonium chloride exhibited strong antimicrobial abilities, deactivating 95. 5% ∼99. 9% of E. coli in quantitative antimicrobial assays.  相似文献   

18.
This study was carried out under Cumra-Konya conditions, in 2007, for the determination of consumption of the plant nutrients from soil by black cumin plants. The soil samples were taken before sowing and after harvest from the field that was sown black cumin and determined the rate of major and minor plant nutrients. For this reason, soil samples were taken from the depth of 30 cm as 2-3 kg and analyzed. The harvested black cumin yielded approximately 1,350 kg/ha seed. The analyses made in soil samples were pH, salinity, organic matter and lime, P, K, Ca, Mg, Na, Cu, Fe, Zn and Mn. According to the results, the parcel soil has not salt problem, and is little alkaline, more limy and little humic, good for phosphorus and very rich with respect potassium before sowing. At the same time, the parcel soil samples after harvest were little saline, little alkaline, more limy, poor humic, good for phosphorus and very rich with respect potassium.  相似文献   

19.
The levels of five mycotoxins (MT): deoxynivalenol (DON), T-2-toxin (T-2), zearalenone (ZEA), aflatoxin (Aft), ochratoxin A (OTA) were measured in malting barley and malt samples by enzyme immunoassay (ELISA), using test systems RIDASCREEN FAST (R-Biopharm, Germany). 40 samples of malting barley, mainly from the Central part of European Russia and fewer from the Southern part of, and also some samples from Altai (Asian Russia) were analyzed during 2007-2011 years as well as 120 samples of malt from Russian malting companies. It was found that 17% of barley samples were contaminated with MT; in two cases (5%), the MT concentration exceeded maximum allowable levels (MAL). Among malt samples in more than half (in 56%) MT were detected, in 9% of samples, the MT concentration exceeded MAL (Aft-3 incidents, T-2-3 incidents, OTA-2 incidents, ZEA-1 incident). Maximum levels ofmycotoxins in malt were found to be higher than those in barley. These facts support the idea about risky conditions during malting processing.  相似文献   

20.
Black aspergilli, the potential ochratoxin A (OTA) producers, were predominant fungi in fermented cocoa bean, coffee bean and dried cassava in Yogyakarta. Identification of black aspergilli at species level will be useful to make clear link between OTA contamination on food product and the toxin producer. The objective of this study was to identify the species of the black aspergilli producing OTA which contaminated dried agriculture products. In this study, 16 isolates were obtained, and four isolates among of them (YAC-9, YAK-6, YAK-12 and YAG-2) were found as OTA producing-strains, with the highest OTA found on Yeast Extract Sucrose (YES) solid medium of 57.68 ppb. Based on morphological characters, 16 isolates can be grouped into four species, after confirmation by molecular data based on PCR method, the groups were identified as A. carbonarius, A. niger, A. tubingensis and A. aculeatus. OTA producing-strains were identified as A. carbonarius and A. niger, meanwhile, A. tubingensis and A. aculeatus were found as non-OTA producing-strains.  相似文献   

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