摘要:

SUMMARYThe thermal destruction rates ofStreptococcus faecalis, ATCC 7080, were determined in a selected group of meat and fish precooked frozen products. Data on heat transfer through these products in a hot air household electric oven, were also obtained. Accordingly, the theoretical thermal treatments required to render such products commercially sterile were computed following the procedure of the General method of process calculation for canned foods with some modification. Inoculated product tests were also made to confirm the adequacy of the computed thermal treatments.It is concluded that the procedure adopted for establishing the thermal treatment was accurate and proved feasible for this type of product. Based on the thermal resistance of our test strain, the heat treatments recommended on the commercial packages seem to be adequate, provided the heating and cooling procedures are similar to those followed in the present experiments. In the case of one product out of the five tested, however, the minimum recommended heating period fell short of the computed thermal requirement for that product.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00772.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYApplication of the 2,4‐dinitrophenylhydrazine method of Roe and co‐workers to plant extracts, wherein ascorbic acid was present largely or completely in the form of DHA and DKA, resulted in abnormal data, in the sense that the value of AA + DHA + DKA was significantlylowerthan that of DHA + DKA. Such a discrepancy, though not to the same degree, was observed also when the analyses were carried out on solutions of DHA. The loss is believed to take place during H2S treatment, there being a correlation between the extent of loss and the duration of H2S treatment, in the majority of the experime

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00773.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe effect of temperature, particularly storage temperature, is one of the most important factors in controlling microbial populations of frozen foods. Adequate temperature control of frozen foods should limit the growth of microorganisms and insure maintenance of original quality and wholesomeness. This investigation was undertaken to show that correct storage temperature; do inhibit the growth of bacteria which might be considered as the source of potential public health hazard, while certain saprophytic species are able to survive and grow well at the same low temperatures. The cultures were all isolated from chicken pies.Bacterial counts were determined by plating techniques on Brain Heart Infusion (BHI) agar after various time intervals up to 30 days at ‐13°, 0°, 5°, 10°, 20° and 37° C, using both BHI broth and chicken gravy as media. Very similar results were obtained in the two media.Escherichia coliandStreptococcus faecalishad a minimum growth temperature between 5° and 10° C for active reproduction. A minimum growth temperature between 5° and 10° C was observed for the culture ofStaphylococcus aureus.Of two cultures representing variants ofPseudomonas fluorescens, one culture followed the growth‐temperature pattern shown by the previously mentioned organisms and failed to grow at or below 5° C. The otherP. fluorescensculture grew rapidly at 5° C. Ability to grow at low temperatures is a constitutive characteristic of the organism and is not common to all types of bacteria. At refrigerator temperatures, the growth of the psychrophilic saprophytic species tested completely outstripped the growth of several bacteria of public health significance. This indicates the great likelihood that a frozen food on defrosting, particularly in a refrigerator, would become completely unacceptable, due to the development of off flavors and odors and deteriorated physical appearance before it became

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00774.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYCell walls of ripening fruits of peach were purified of a large part of their non‐cellulosic components and examined with X‐ray techniques. Small, but distinct, increases in micellar size, and perhaps in percentages of crystallinity, are a function of the maturation process. These increases are interpreted as evidence of a limited degradation of cellulose (broadly defin

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYAn X‐ray diffraction study was made of several plastic fats, including lard, butterfat, oleomargarine, and hydrogenated vegetable shortenings. Their liquid contents were varied by altering the holding temperature. Separate mixtures were made of cocoa butter or tristearin with corn oil, tributyrin, or trioctanoin, and their diffraction patterns were obtained. The crystal form (omega), previously described for oxidized cocoa butter, was found in the first group of fats and in the corn oil‐tristearin mixture. Omega crystallinity was not related to the solid‐liquid ratio of the fats or to differences in molecular length in the constituent fatty acid radicals. Omega crystallinity seemed to be related to a general difficulty in crystallization, probably due to steric hindr

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe carotenoids of ripe tomatoes were found to contain about 6% xanthophylls; the composition of the latter was about 15% monols, 49% diols, 4% monoepoxide diols, 22% diepoxide diols, and 11% polyols. The diol and polyol xanthophylls were much like those of green leaves, with lutein the major pigment, somewhat smaller amounts of violaxanthin and neoxanthin, and much smaller amounts of zeaxanthin, lutein 5,6‐epoxide, and several others.The monol fraction contained lycoxanthin and “monol 487” (which may be 3‐hydroxy‐delta‐carotene), together with substances tentatively identified as polycisisomers of lycoxanthin, rubixanthin, and

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYA protein from beef prepared by ammonium sulfate fractionation of a hot‐water extract, gave a “wet dog” odor when irradiated. This protein has an amino acid constitution similar to that of gelatin, is associated with a nitrogen‐containing polysaccharide, and exhibits the solubility properties of a glucoprotein. When irradiated, 15% of the nitrogen becomes dialyzable and 13% of the amino acids are destroyed. The sulfhydryl content decreases markedly, whereas the ammonia, as determined after acid hydrolysis, and the ultraviolet absorption increase. Similar radiation‐induced changes can be observed with proteins that do not produce an odor. Consequently, the odor discussed in this report does not appear to be produced from simple amino ac

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00778.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe sensitivity of the pad‐plate method for detecting chlortetracycline in egg white is increased by using pH 4.5 citrate buffer rather than pH 4.5 phosphate buffer as a diluent. It is also increased by allowing about four hours for diffusion of antibiotic prior to incubation of the assay plates. Under these conditions of assay, protein binding of the antibiotic was not an important facto

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00779.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYAccessory foods like jelly or catsup can be evaluated by consumers for preference without an appropriate carrier, such as bread or hamburger, at least as effectively as with the carrier. Time and money are saved, and accuracy is increased.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00780.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYSeasonal changes in concentrations of pectic substances of the peel and pulp were followed by determining the total‐ and water‐soluble pectic substances as an‐hydrogalacturonic acid during growth and development under normal conditions. With the rapid development of fruit growth in the early part of the season, a tremendous initial increase occurred in the total‐ and water‐soluble pectic materials followed‘by a gradual decrease through the remainder of the season. The percentage methylation of the pectic substances of Valencia orange peel rises rapidly to approximately an 80 per cent level and remains relatively constant during the rest of

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00781.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY