摘要:

SUMMARY—Organoleptic and chemical deterioration of freshwater whitefish muscle frozen at −10°C for periods up to 16 weeks was assessed. As frozen storage of muscle progressed, the toughness and rancidity of baked muscle increased. The solubility of the myofibrillar protein fraction, “actomyosin,” dropped from about 72 to 22% over the 16 week storage period of whitefish muscle. No change in the solubility of sarcoplasmic protein in frozen stored muscle was observed. However, with polyacrylamide disc electrophoresis, two new sarcoplasmic protein bands were detected after 16 weeks of storage. With storage of frozen muscle, water‐binding capacity diminished. Although the total lipid and cholesterol contents of muscle remained constant throughout frozen storage, the phospholipid content decreased as the free fatty acid content increased. Oxidative deterioration of lipid in frozen muscle was

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14350.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Beef adipose tissue was separated into the water soluble, salt soluble and insoluble (water‐salt‐ether) fractions, and the amount of H, S evolved upon heating each of the fractions was determined. The yield of H, S per 100 g of adipose tissue was 17.6, 1.7 and 5.5 μM for the water soluble, salt soluble and insoluble fractions, respectively. Thus, the water soluble fraction contributed about 71% of the H, S, while the corresponding contributions from the salt soluble and the insoluble fractions amounted to approximately 7 and 22%, respec

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14351.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—The lipid composition of Baltic herring (Clupea harengus var. membranus) muscle and the hydrolysis during freeze storage was studied with thin‐layer chromatography. The concentrations of the various lipid classes were initially 2–5 times as high in dark muscle as in white muscle. Storage for up to 12 weeks at –15°C resulted in an increase of the free fatty acid content from 50 to 1000 mg/100 g in the dark muscle, and from 17 to 280 mg/100 g in white muscle. The increase was due to hydrolysis of lecithin, cephalin and to a varying extent also of triglycerides. According to indirect estimations, roughly 45 and 75% of the free fatty acid formed in dark and white muscle respectively was a result of phospholipid hydrolysis; the remainder of triglyceride hydrolysis. The hydrolysis of lecithin was faster than that of cephalin in both types of muscles. The enzymatic attack showed no preference for anyone of the different fatty acids in the phosp

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14352.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Experiments with cooked, freeze‐dried beef support previous evidence that changes in its physical and chemical properties are reflected in its water sorption characteristics. As a new approach, sorption isobars and their hysteresis were studied. In the reported temperature and pressure range, a decrease in the sorption capacity and in the area of the hysteresis loop was observed after 1 yr of stor

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14353.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—The tyramine levels in different varieties of cheeses, alcoholic drinks, and other foods were determined. Many of the food samples, analyzed by an existing fluorometric method, contained large amounts (up to 2.2 mg/g) of tyramine. Synephrine and octopamine, although rarely present in food, interfered with the fluorometric analysis. A gas chromatographic method was developed in which tyramine was extracted from foods and then analyzed as its trifluoroacetyl derivative using an electron capture detector. The gas chromatographic method was more sensitive and specific than the fluorometric method, and it permitted detection of 0.1–0.2 nanogram tyramine even in the presence of synephrine and octopam

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14354.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Radiopasteurization is an effective means of preserving haddock fillets of varying marketable quality. While results show that the postirradiation shelf life was a function of the preirradiation quality, they also indicate that there was an economic benefit from irradiating the fillets cut from fish as old as 13 days after catchin

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14355.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Gas‐liquid partitioning of head‐space vapors offers possibilities as a quality control procedure, permitting rapid identification of certain bacteria of sanitary and public health significance in foodsRepresentative organisms of the following genera were studied:Escherichia, Salmonella, Citrobacter, Enterobacter, Proteus, AlkaligenesandPseudomonas. The head‐space vapors over synthetic broth cultures were analyzed by gas chromatography in an effort to obtain reproducible patterns differentiating the bacteria. Selected food materials were inoculated with two cultures (Salmonella and Enterobacter) and, after storage at 5°C, the foods were examined by the chromatographic procedure.Analysis of head‐space vapors over dextrose fermenting bacterial cultures by gas‐liquid partitioning produced chromatographic patterns differentiating members of the familyEnterobacteriaceae. Two food materials inoculated with test organisms evidenced presence of Salmonella andEnterobacterwhen submitted to analysis. A third food material was initially contaminated with a mixed flora; gas chromatographic analysis indicated the presence of members of the familyEnterobacteriaceae.It is concluded that gas chromatographic analysis of head‐space is a reproducible method and can be applied to routine microbiological examin

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14356.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Frozen whole egg containing known amounts of lactic and succinic acids were evaluated using gas‐liquid chromatography (GLC) and AOAC (1960) procedures. The acids were isolated from the whole egg samples by liquid‐liquid extraction, evaporated to dryness, and refluxed for 2 hr with 1‐butanol and HCI and chromatographed as their butyl ester derivatives, along with an internal standard. Peak heights and responses relative to butyl decanoate as an internal standard were used to calculate acid concentrations in the whole egg samples.Lactic acid recovered from whole egg samples by GLC procedures ranged from 98% at the low concentration (0.43 mg/100 g egg) to 99% at the high concentration (47.70 mg/100 g egg). Succinic acid recovered from whole egg samples by GLC procedures ranged from 103% at the low concentration (1.22 mg/100 g egg) to 98% at the high concentration (73.20 mg/100 g egg). Acid recoveries from whole egg samples by GLC procedures were as accurate, and generally less variable, than those recovered by AOAC (1960) pro

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14357.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Experiments were conducted to determine the effect of post‐mortem temperatures between 0 and 20°C on the degree of shortening in isolated pectoralis major muscles of chickens and turkeys. A “cold shortening” effect in these muscles is described and compared to post‐mortem pH, average sarcomere length of isolated myofibrils, and relative solubility of myofibrillar and sarcoplasmic proteins.The degree of muscle shortening at each temperature after various periods post‐mortem indicated that shortening was essentially complete after 3 hr in chickens and 5 hr in turkeys. Shortening in muscles stored at 0°C was significantly greater (P.05) with shortening. Extractability of myofibrillar and sarcoplasmic proteins after 5 hr at either 0 or 16°C was determined and found to be unrelated to the degree of po

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14358.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Chromatographic estimations of tyramine and histamine in “Marmite” and four other yeast extracts showed a tyramine content from 0.1 to 1.6 mg/g and a histamine content of 0.2 to 2.8 mg/g. “Marmite” contained the largest amounts of both amines, but’ three samples of this extract showed a wide range in amine content. These variations in amine content of yeast extracts are discussed in terms of their manufacture. Pharmacological activity in one of the yeast extracts (“Marmite”) on the rat's blood pressure and on the intact bronchioles and isolated ileum of the guinea pig was due to the presence of tyramine and histamine. The clinical relevance of a high histamine conte

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14359.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY