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关键词： Shear thinning  

摘要： Application of both homogenization and microfluidization offer remarkable reformations in the structures of food. In this research, the outcome of the homogenization and microfluidization on the emulsion of mayonnaise and resultantly on the rheological and sensory attributes of the mayonnaise was evaluated and compared. Implementation of individual processes was analyzed with regard to rheological properties and physicochemical parameters by preparing samples with and without addition of stabilizers. Mayonnaise samples showed thixotropic behavior and then categorized as shear thinning (Pseudoplastic liquid) showing yield stress. Irrespective of sample testing parameters such as different temperatures and shear rates, all samples revealed shear thinning characteristics. The viscosity of microfluidized sample with or without stabilizer was significantly increased (p < .05) as judged against the homogenized sample at both temperatures (20 degrees C and 40 degrees C). The storage modulus of all samples was higher as compared with the loss modulus which shows elastic nature of the mayonnaise. Power law and Weltman model were studied to explain the rheological behavior of the mayonnaise and both models were found best suited. Experimental values illustrated through attempted models very well contribute to future studies on the product and process development. As per the current literature, microfluidization can be used to achieve quick mayonnaise emulsion with better rheological characteristics and hence superior sensosry attributes. Practical Applications Stabilizers play a critical role in the development of mayonnaise as an additive or constituent. The present study reveals that high-pressure homogenization (microfluidization) can be exploited to enhance rheological, physical, and chemical properties of the mayonnaise by influencing interaction between fat (oil) and gums (polysaccharides), eventually increasing viscosity. The quality of mayonnaise is usually judged by

关键词： Bound phenolic acids   in vitrodigestion   interaction   pasting properties   purple sweet potato starch   thermal properties  

摘要： Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was employed to investigate free phenols that were released from purple sweet potato (PSP) by alkaline, acid and enzymatic hydrolysis. Four phenolic acids, including ferulic, isoferulic, 4-hydroxybenzoic and caffeic acids, were identified. Based on their effects on the characteristics of purple sweet potato starch (PSPS), the four phenolic acids were studied. Furthermore, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques were employed to explore the microstructures of the complexes of the phenolic acids and PSPS. The obtained results demonstrated that the pasting, thermal, retrogradation, as well as digestive properties of PSPS were all influenced by the phenolic acids which interacted with PSPS through noncovalent hydrogen bonds. The influence of the four phenolic acids on the properties of PSPS was in the descending order: 4-hydroxybenzoic acid > ferulic acid > caffeic acid > isoferulic acid.

关键词： Chitosan   Chitosan-silver nanocomposites   Swift heavy ions irradiation   Physicochemical properties   Dielectric spectroscopy  

摘要： Self-sustained films of biodegradable chitosan (CS) and chitosan-Ag nanocomposites (CSN) were prepared by chemical route followed by C+5 and Ni+7 ions irradiation with varying fluences. The crystallite size decreased from 11.1 to 2.7 nm for CS and 17.6 to 14.2 nm for CSN with increasing ions fluence as observed from the analysis of X-ray Diffraction (XRD) spectra. ATR-FTIR spectra revealed assorted vibrational modes and degradation of polymeric chains in both, CS and CSN matrices upon irradiation. The molecular interactions between main and side-chain functional groups impeded due to nanoparticles confining effects. MeV ions yield low-molecular-weight fragments with degassing of some volatile gaseous species during irradiation. An acute amendment in absorption spectra ascribed to change in surface color and differential absorbance at the wavelength of 370 nm showing blocking of UV radiation. The formation of conjugated linkages and carbonization of CS and CSN matrices lead to decrease in bandgap. Modifications in the physicochemical properties were found to be in persuasive association with changes in frequency-dependent dielectric responses. The shape parameter was moderately decreased and indicating non-Debye relaxation. The conductivity of CS and CSN matrices enhanced and follows the universal dielectric response. The amendment in surface morphology was also revealed upon irradiation.

关键词： Physicochemical properties  

摘要： The effect of high pressure processing (HPP) at 300, 400, and 500 MPa combined with Lactobacillus acidophilus was assessed on uncooked ground beef patties (BP) during refrigerated storage of 10 days. BP were evaluated in terms of microbial growth, color, pH, and lipid oxidation during the storage. Untreated BP had a significantly higher total aerobic count (6.74 log CFU/g) than BP treated with HPP 500 MPa + L. acidophilus (3.35 log CFU/g) on Day 10 of storage. Yeasts and mold counts of only 0.80 log CFU/g were detected in BP treated with HPP 500 MPa + L. acidophilus on Day 10 of storage. BP treated with combined process showed significant color retention, a delayed decrease in pH value, and inhibition of lipid oxidation during storage. The HPP 500 MPa + L. acidophilus showed the highest scores for all sensory parameters. This combined process can be used as an effective treatment for maintaining the microbial stability and quality of BP during storage. Novelty impact statement High pressure processing at 500 MPa was applied as a postprocessing treatment in conjunction with lactic acid bacteria for improving the microbiological safety and enhancement of shelf-life of fresh ground beef patties during refrigerated storage for intended usage at home and fast-food restaurants.

关键词： Heat treatment   Rice protein   Protein interactions   Protein digestibility  

摘要： The effects of heat treatment on protein interaction, surface hydrophobicity, protein profile, amino acid composition, and in vitro digestibility of individual rice protein fractions were investigated. Heat treatment at 100 degrees C for 20 min had no negative effect on essential amino acids in rice protein. Surface hydrophobicity increased significantly with the increased heat treatment temperature. Moreover, free-thiol content decreased significantly with increased temperature and time extension. Hydrophobic interactions contributed to the heat-induced interaction of glutelin and prolamin. Intramolecular disulfide linkages participated in the heat-induced interaction of all rice-protein fractions. Heat treatment had no effects on the in vitro digestibility of glutelin, globulin, and albumin. Thus, the heat-induced interactions of glutelin, globulin, and albumin were not related to their digestibility. By contrast, the formation of intramolecular disulfide bonds and hydrophobic interactions in prolamin may reduce its digestibility by strengthening protein bodies-Is.

摘要： Plant proteins have been increasingly recognized as very relevant food ingredients, due to concerns related to ecology, health and even religion. However, compared to food proteins from animal sources, the former ones have considerably lower dispersibility. Because of this, exploring techno-functional properties of plant proteins in formulations is much more difficult. Ultrasound has been explored in food processing for different purposes and represents a strategic non-thermal operation to enhance the dispersibility (and, consequently, several techno-functionalities) of food proteins. During ultrasonic processing in aqueous medium, the concentration of protein material may favour or impair the action of ultrasound waves, but this fact has been only marginally addressed in literature. Hence, this study investigated the effects of different protein concentrations during ultrasonic processing on techno-functional properties of soy protein isolate (SPI), rice protein isolate (RPI), and pea protein concentrate (PPC). Ultrasonic treatments (USt) at 20 kHz were designed using a Box-Behnken experimental planning, varying ultrasound power (562.5, 637.5 or 712.5 W), application time (120, 360 or 600 s), and concentration of the proteins in aqueous medium [1.0%, 3.0% or 5.0% (w/v)]. Hydrophobic surface index (H0), molecular mass profile, hydrodynamic diameter (dh), and -potential of these three protein materials after USt were evaluated and discussed. Moreover, Response surface methodology was applied to evaluate and to optimize the following techno-functionalities of SPI, RPI, and PPC: water and oil holding capacity (WHC and OHC), and foaming, emulsifying, and gelling properties. After USt, OHC increased for the three protein materials. For SPI, dispersibility and FC at 712,5 W vertical bar 600 s vertical bar 1.0 % w/v were improved. The WHC (562.5 W vertical bar 120 s vertical bar 5.0 % w/v), OHC (562,5 W vertical bar 120 s vertical bar 1.0 % w/v) of SPI were also increased.

关键词： chicken sausages   fish oil   microencapsulated fish oil   vacuum packing   modified atmosphere packing   physicochemical properties   microbiological analysis   sensory assessment  

摘要： The aim of the study was to evaluate the influence of refined fish oil additives in liquid and microencapsulated forms, packing method (VP-vacuum packing, MAP-modified atmosphere packing) and storage time (1, 7, 14, 21 days) on selected physicochemical, microbiological and sensory characteristics of minced poultry sausage. Principle component analysis (PCA) showed that the fish oil additive, packing method and storage time significantly influenced some of the physicochemical characteristics of the sausages. The pH value was negatively correlated with the type of sample and packing method. The water activity decreased along with the storage time. The sausages with microcapsules had distinguishable hardness, gumminess and chewiness than the other samples. This tendency increased in the subsequent storage periods. The packing method and storage time of the samples had a statistically significant influence on the growth of the total colony count and count of lactic acid bacteria (p < 0.05). The most aerobic bacteria were found in the control sample, and the least in the sample with microcapsules, regardless of the packing method. The use of MAP and the addition of microcapsules resulted in the lowest microbiological contamination of the sausages. The sensory analysis made by a trained panel did not show any significant differences between the samples. After 21-day storage of the sausages there was a slight decrease in some of the sensory parameters, e.g., color, smell, taste. The liquid oil and microencapsulated oil additives in the meat filling did not negatively affect the taste or any physicochemical characteristics of the meat products. From the microbiological perspective, there were better effects from the MAP method.

关键词： Gelatin   Guar   Rice Bran   Tablet   Xanthan  

摘要： Nowadays, consumers pay attention to the health-related properties of the food as well as their nutritional worth. Rice bran includes high amounts of proteins, fats, minerals, B vitamins and dietary fibers. These properties can contribute to health enhancement through declining the rate of cancer, cardiovascular diseases, renal stones and hyperlipidemia. In this study, the influence of gelatin, xanthan, and guar gums (at 0, 5, and 10%) on the physicochemical, shelf life, sensory and image properties of functional rice bran tablets was investigated. The results displayed that the gums addition leads to changes of tablets chemical properties. The acidity and peroxide content of the gum-containing samples was significantly lower than the control sample. The highest amount of disintegration time, hardness and moisture content was observed in samples containing 10% xanthan in first and 30th days of storage. Sensory analysis revealed that gelatin, xanthan and guar did not significantly affect the color, aroma, taste and flavor of the rice bran tablets. Sensory panelists liked the samples containing 10% xanthan in terms of texture and overall acceptance as an excellent food supplement. Principal component analysis (PCA) allowed categorizing specialties. Partial least squares regression (PLSR) models were applied to find out the relationships between sensory and instrumental data.

关键词： application timing   japonica rice starch   mid‐   stage nitrogen   morphological structure   physicochemical properties  

摘要： BACKGROUND Nitrogen management of crops, especially when mid-stage nitrogen is applied, is a key factor affecting the yield and grain quality of rice (Oryza sativa). Here, the timing of mid-stage nitrogen application was evaluated for its effect on rice grain quality by assessing the morphological structure and physicochemical properties of starch from two japonica rice cultivars growing in fields (Nangeng 9108 and Nangeng 5055). RESULTS The experiment was arranged in a split-plot design, with the two rice cultivars as the main plot factor and three timings of mid-stage nitrogen application as the within-plot factor. Briefly, three applications were made: at the emergence of the top-sixth-leaf (ahead), the top-fourth-leaf (normal), and the top-second-leaf (delayed) of the main stem. Delaying mid-stage nitrogen application caused the starch granule surface to become uneven and significantly reduced its particle size, whereas it increased the polished rice rate, chalkiness degree, and protein content. Furthermore, the apparent amylose content decreased with a delay in mid-stage nitrogen application, thereby resulting in higher relative crystallinity, swelling power, water solubility, gelatinization enthalpy, and low retrogradation. Finally, we also found that delaying this nitrogen application lowered the characteristic values of rice flour viscosities, leading to cooking quality deterioration. CONCLUSION These results therefore suggest that delaying mid-stage nitrogen application enhances the processing and nutritional qualities of japonica rice but evidently has an adverse effect upon its appearance and cooking qualities. (c) 2020 Society of Chemical Industry

关键词： Insoluble soybean fiber   Homogenization sequence   Structure-function relationship   Emulsion stability   Network stabilization  

摘要： Comprehensive utilization of okara has received a growing interest from manufacturers and researchers in the food industry. In this work, ISF was extracted from defatted okara in the sequence of "homogenization followed by pH12 treatment" and "pH12 treatment followed by homogenization", which are indicated as HA-ISF and AH-ISF, respectively;Subsequently, the basic properties and initial structure of these ISFs, as well as their emulsification performance were systematically characterized. The results indicated that as the homogenization intensity was enhanced, more negatively charged, smaller particle as well as porous structures were detected in the extracted ISF. The size of oil droplets in ISF-emulsions decreased and then increased, the absolute value of the zeta-potential and the loss angle (tan delta) were reduced, the apparent viscosity and elastic modulus (G') increased, and the flocculated structure in the ISF-emulsions was promoted as the homogenization intensity was increased. Creaming in the ISF-emulsions was effectively inhibited by homogenization via adsorption of ISF onto the interface and network stabilization. More obvious aforementioned changes were observed in AH-ISF than HA-ISF, as well as in the corresponding emulsions. These results provided valuable information for the exploitation of ISF as emulsifier, which is a promising approach to enhance the added-value of okara.