摘要:

ABSTRACTOn June 1, 1983, the Food Safety and Inspection Service of the U.S. Department of Agriculture issued a final regulation regarding cooking and cooling requirements for roast beef. This regulation includes a specification of the time that the cooked roast may be exposed to temperatures in the range 120°F (332K) and 55°F (285.93K), no more than 6h, and that chilling must continue until the center temperature reaches 40°F (277.6K) before packaging. the purpose of this work was to suggest means by which processors may estimate these temperature limits. Several measured temperature profiles at the center of the roasts were obtained from beef processors, h was found that the measured temperatures obtained during the cooling of cooked roasts by ice water, may be predicted satisfactorily by methods described in this paper. Cooling with cold air introduces a boundary layer resistance to heat transfer and possibly also mass transfer because of potential evaporation of water. However, in this latter case further investigation is needed to determine its effect on the cooling of moist food products; the use of heat transfer considerations alone gave reasonable agreement with measurement in this particular instance. It appears that ice water velocities should be kept in excess of about 0.076 m/s to ensure that minimal surface resistance to heat transfer occurs during cooling; ice water velocities in the order of 0.15 m/s seem to lead to excellent cooling conditio

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1987.tb00129.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACTAn equation for predicting filtration flow rates in the presence of sedimentation at constant pressure drop was developed. It was applied to determine the average specific cake resistance infiltration of starch slurries at 18.8 to 115 kPa pressure drop range. At these conditions, corn, potato and sweet potato starch filter cakes were incompressible but wheat starch cake was compressible.

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1987.tb00130.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACTA comparative study of three mandarins of Chios, Satsuma and Clementine varieties was carried out to determine the appropriate conditions for lye peeling of fruit segments.The peeling process was both temperature and alkali concentration dependent. the time‐temperature correlation was linear while the effect of the alkali concentration was exponential.At low temperature the “Clementine” exhibited higher sensitivity to alkali concentration than the other varieties, while at the highest temperature the “Chios” mandarin was the most

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1987.tb00131.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACTA model to predict the temperature history of the slowest heating point during venting of steam retorts is proposed. the theoretical analysis was based on a physical interpretation of the system behavior. the model was used to evaluate the influence of steam flow rate and initial temperature on venting time, steam consumption and temperature distribution in a pilot scale horizontal retort.

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1987.tb00132.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACTA simplified analytical model for the freezing time prediction of simple‐shaped foodstuffs was developed. It was assumed in the model that the solution to the unsteady state, unidirectional heat conduction equation with constant thermophysical properties was valid during cooling and freezing. the latent heat effects during freezing were incorporated into an effective diffusivity term. the predictions of the model were compared to the available experimental data on freezing of infinite slabs, infinite cyliners and spheres, and to the experimental data obtained in this research for the freezing of apples. the level of agreement between the predictions and the experimental data was quite satisfactor

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1987.tb00133.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY