摘要:

ABSTRACTThe elastic modulus of orange juice ice as well as pure water ice was measured at temperatures between − 10°C and − 196°C by compression tests. the elastic modulus of pure water ice was almost constant in the whole range of the tested temperatures: 5.6 × 109N/m2at − 196°C and 4.0 × 109N/m2at − 10°C. In contrast, the elastic modulus of orange juice ice changed greatly with temperature: 11 × 109N/m2at − 196°C and 0.2 × 109N/m2at − 10°C. Orange juice ice was considered to consist of pure water ice particles which are dispersed in a matrix of concentrated amorphous solution (CAS). the elastic modulus of CAS was calculated using an equation

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1991.tb00077.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACTAn elementary theory of stress pulse propagation was applied to a one‐dimensional mathematical model for cryo‐comminution of agglomerated granules into individual granules. an assembly of granules is approximated by a bar constructed with blocks stuck together. When an impulsive loading is given at one end of the bar, a compressive stress pulse generates there and propagates through the bar. When it survives after transmitting through the interfaces between blocks and reaches the opposite free end, the compressive stress pulse turns into a tensile stress. This tensile stress causes separation of the block located farthest away from the loading end, provided the intensity of the stress pulse exceeds the tensile strength of the material. the model successfully explained the experiment on shattering orange juice ice as well as frozen citrus fr

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1991.tb00078.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACTTangerine (Citrus reticulatablanco) juice clarification by crossflow microfiltration and ultrafiltration using polysulphone flat sheet membranes with nominal molecular weight cut off of 25,000, 50,000, 100,000 and 0.1 μm, 0.2 μm pore sizes was studied. the juice was pretreated by polygalacturonase and pH adjustment. the treated juice was clarified with a laboratory scale filtration unit with effective filtration area of 14 cm2. Filtration conditions were transmembrane pressure of 93 to 194 kPa, crossflow velocity of 0.96 to 3.5 m/s and 25°C. Membrane performance was evaluated in terms of volume flux and clarity (% transmittance) of the permeate.Pretreatment of the juice by polygalacturonase and adjustment to pH 2 with HCl resulted in a clearer supernatant than enzyme treatment alone. Maximum flux was obtained with the 0.1 μm microfiltration membrane. Flux increased with transmembrane pressure and crossflow velocity. Flux at 194 kPa and 3.5 m/s was 69 L per square meter per hour. Permeate clarity was better at higher transmembrane pressure and lower velocity, due to the effect of the polarized/fouling layer of solute on the membrane surface, which acted as a secondary “dynamic”

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1991.tb00079.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACTA cylindrical shaped thermal scanning rigidity monitor (TSRM) was developed to determine shear rigidity modulus of meat batters during cooking. A meat fatprotein ratio of 1.8, moisture content of 62% and 8.6% filler were used. the fillers were buttermilk powder, corn starch, micro‐crystalline cellulose, modified corn starch, modified wheat flour, soy‐protein concentrate and whey‐protein concentrate. Plots of rigidity modulus versus product‐temperature showed two major thermal transitions. the first and most important transition (53 to 61°C) was due to myosin gelation. the second transition (64 to 69°C) was ascribed to the collagen softening. the maximum rigidity‐temperature slopes of 0.60 to 1.02 kPa/°C occurred after the firs

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1991.tb00080.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACTThe expression of liquid from a solid‐liquid matrix of oil‐bearing material is a complex process and is incompletely understood. an investigation was taken up to understand the phenomena relating to compression and consolidation of rice bran and gain an insight into the flow behavior of oil under uniaxial compression. A mathematical model based on one‐dimensional consolidation theory (Terzaghi 1943) was developed with suitable assumptions, taking into account the test‐cell geometry. the experiments were conducted with two types of parboiled rice bran; original unsieved bran and bran sieved through B.S. 30 mesh. the developed model was tested and a close agreement was found between calculated and observed

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1991.tb00081.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

ABSTRACTProcessing activities such as drying expose grains to temperature and moisture gradients resulting to increased susceptibility of corn breakage. the effect of rehydration and redrying rates on the breakage susceptibility of corn was compared and evaluated. Dried corn samples were rehydrated and redried artificially. Breakage susceptibility of the samples were tested using a food grinder (blender) and Instron testing machine. Treatments consisting of a cycle of rehydration and redrying represented different rates of moisture sorption. Initial sample moisture, rehydration methods and redrying temperatures were used in comparing breakage susceptibility.Samples of low initial moisture had higher breakage susceptibility as compared to higher initial moisture samples. the rehydration method representing the highest moisture adsorption rate resulted to samples which were more susceptible to breakage than the two rehydration methods representing intermediate and slow rates of moisture adsorption. Temperature of redrying also showed significant effects with high temperatures (80°C) resulting to grains with higher breakage susceptibility compared to samples redried with unheated air (30°C). Breakage susceptibility increased when samples were rehydrated and increased much more when they were redrie

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1991.tb00082.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1991.tb00083.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY