摘要:

ABSTRACTTechniques used in the analysis of diffuse reflection and transmission in intact foods such as peaches and oranges are summarized. Examples are given to provide a basis for establishing the methods used for reduction of spectrophotometric data. Procedures for data analysis with computers are given along with examples of instrumentation.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03420.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTInaccuracies in the Formula method for thermal process evaluation–which could lead to overestimates of the lethal value and reduce the margin of safety of processes‐were found. Revised tables for C:g and fh/U:g systems are presented as well as revised coefficients for polynomials fitted to the tables for use in programmable calculat

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03421.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTA series of experiments was carried out to determine the freezing time of cylindrical and spherical blocks of a widely used food analogue material. These results were used to assess the accuracy of calculation methods in the literature, including both numerical (computer) and modified analytical methods. A three‐level implicit finite difference scheme was developed which gave good accuracy, but no better than an extension of an analytical method which is therefore advocated on the grounds of ease of use. It covers the range, of conditions most likely to be encountered in practical food freezing situation

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03422.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTA previous study of methods for predicting the freezing times of slabs, cylinders and spheres was extended to cover rectangular bricks of food materials. Experimental measurements of the freezing time were made over a wide range of conditions using a food analogue material, and these results compared to times calculated from various available prediction methods. The three‐dimensional version of a three time‐level finite difference scheme was found to be the most accurate numerical solution. Simple formulae are available for predicting the freezing time of rectangular bricks using the geometric factors derived by Plank. These factors are shown to be subject to error, and none of this group of methods gave accurate prediction of freezing time. A previously proposed group of formulae are extended to cover rectangular bricks. These formulae are simple to use and accurate. They are applicable to slabs (±5% with 95% confidence), and to cylinders and spheres (±7% with 95% confidence) as well as to bricks (±10% with 95% confidence). These extend the previously published formulae for slabs, cylinders and spheres without significant loss of ac

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03423.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTOnion powder in commercial bulk containers was irradiated with a minimum average gamma radiation (60CO) dosage of 900 Krads. Taste and flavor evaluation by a modified profile method failed to show statistically significant differences immediately after treatment or during 12 month storage. A sample irradiated with an excess dosage of 27,000 Krads showed some changes from raw toward cooked onion characteristics but no abnormal characteristics.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03424.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTIncreasing dosages of gamma radiation from Cobalt‐60 source resulted in an almost linear reduction of the Aerobic Plate Counts (APC) in onion powder. An average minimum exposure of 900 K‐rads was chosen to achieve reduction in counts to below 25,000 per gram even for powders with high initial counts. Treatment was equally effective in powders of different qualities. Powder in commercial packs (55 gal drums or 5 0‐1b bag‐in‐box) showed the expected reduction in counts; in addition, further significant reductions in counts occurred over a 12‐month storage period. After the initial irradiation treatment coliforms, yeasts and molds were no long

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03425.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTThe sampling distributions of aflatoxin in fresh and roasted pecans, visible mycelium in fresh pecans and total plate count in ground beef were examined using the chi‐square and Kolmogorov‐Smirnov tests. The Kolmogorov‐Smirnov test was found to be more conservative than the chi‐square test and a powerful technique for rejection of null hypotheses. The results indicated that many sampling distributions used in quality control of foods deviate significantly from the normal distribution. The sampling distribution for total plate count in ground beef and the distribution of sample means were determined. A critical sample size of at least 5 was found to be necessary to approximate the normal distribution for the sample means. The average and standard deviation control charts utilizing the sample size of 5 were established to illustrate the detection of out‐of‐cont

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03426.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTThe successful detachment of sweet corn kernels as intact kernels promises large yield and effluent advantages over cut kernels during processing but requires a low strength of kernel attachment to the cob. This work describes the development of a test method for measuring the strength of kernel attachment and applies it to the identification of %varietal differences. Two components resisting detachment were identified: a base or abscission component and a side or frictional component. Base components as low as 1.3 Newton (N) (Golden Happiness) and as high as 5.5N (Illini Xtra Sweet) and side components as low as 1.3N (Vanguard) and as high as 4.0N (Golden Happiness) were observed. Abscission strength was found to correlate with prototype machine processing variables such as kernel mass production rates and the completeness of kernel removal from the cob.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03427.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTTests at a commercial plant showed that a new in‐line steam process was better than the existing process in conditioning inshell pecans for cracking, as determined on the basis of shelling efficiency, or yield of unbroken nutmeat halves. Steam conditioning was more effective than commercial conditioning in reducing total plate count and yeast and mold count on the product. Peroxide and free fatty acid values of oils, Hunter color values of nutmeat halves and sensory taste analyses indicated that the quality of the nutmeats conditioned by the two methods was essentially the same immediately after conditioning. Commercial test results agreed with results of previous pilot‐scale stud

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03428.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTThe use of high pressure liquid chromatography (HPLC) in determining total and available lysine was studied. Protein‐carbohydrate mixtures were analyzed for available lysine by reaction with fluoro‐dinitrobenzene (FDNB) and separation of e‐DNP‐lysine by HPLC. When comparing the HPLC method to an FDNB spectrophotometric method, the latter gave higher results. The difference was attributed to compounds formed during hydrolysis that interfered with the spectrophotometric method. Total lysine was determined in food proteins by reacting hydrolysates with dansyl chloride. HPLC was used to separate and quantify didansyl

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1979.tb03429.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY