ISSN:0022-5142    

DOI:10.1002/jsfa.2740020302

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe F value of a heating process as applied to a can of food is defined as the time in minutes at 250° F., assuming the whole can to be raised instantaneously to this temperature and cooled instantaneously to a sub‐lethal temperature afterwards, that would give the same degree of sterility as the process to be valued. The implications of the term ‘degree of sterility’ are discussed.Equations are developed and tables are given, applicable to pure conduction packs only, for estimating the F value of a process for a small finite volume at the centre of a cylindrical can. Such a value has hitherto been used to represent the F value for the whole can. It is here designated the Fcvalue. The effects of the relative dimensions of the can, of pre‐processing procedures and of the coming‐up time of the retort are considered. The Fcvalue is independent of the absolute heat resistance of the organisms to be killed, assuming the same temperature‐time relationship.A method is presented for estimating the F value for the whole can from the Fcvalue. The F value is shown to vary with the heat resistance of the organisms for which the degree of sterility attaine

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020303

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe total nitrogen content of 16 commercial samples designated as bone meal showed a wide range of values from 2.12 to 5.55%. Samples of bone meal were added to soil in quantities equivalent to 300 p.p.m. nitrogen in each case, and the fraction of the total nitrogen readily converted to ammonia and nitrate was determined after incubation for nine days at 23.5° c.; these fractions so converted were significantly correlated with the percentage of the total nitrogen that was soluble in water. Significant correlations were also found with the bulk densities and sieve analyses of the milled samples, the pH of their aqueous suspensions, and the ammonia liberated on distillation with magnesia. The effect of different degrees of milling upon the results of the tests was examined for selected samples

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020304

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractCalcium is separated as oxalate in a centrifuge tube. The precipitate is estimated by dissolving in a known excess of ceric sulphate, excess of which is then determined absorptiometrically. The range covered is 100–1000 μg. calci

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020305

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020306

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe seed fats of these West African species of plants contain 15–20% of saturated acids (mainly behenic or lignoceric) of higher molecular weight than stearic acid; the unsaturated acids are confined to oleic and linoleic in varying proportions. The composition of the mixed glycerides in the fats conforms closely to the usual ‘evenly‐distributed’ type. Although the fats are probably capable of use as supplementary sources of edible fats, the presence in appreciable proportions of behenic and/or lignoceric acid is disadvantageous either for edible purposes or, more especially, for soap making. In a specimen of deteriorated seed fat from Lophira alata, it was observable that the behenic acid present had proved relatively resistant to enzyme

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020307

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020301

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY