摘要:

ABSTRACTGrowth of enterotoxigenicS. aureusand production of enterotoxins (A and D) during curing, smoking and drying of pepperoni were evaluated by inoculating raw ingredients with 104, 105, or 106S. aureus/gand processing by two different approved (USDA) methods. The product was smoked for 1 hr and heated to 40°C within 5 hr in method I and smoked for 1 hr followed by heating to 49–50°C within 11 hr in method III. The pepperoni sticks were then dried at 10–12°C for 4–5 wk. Total viable plate count (plate count agar), plate count on Rogosa's SL medium (RSL) and Saureuscount on Baird‐Parker medium (BP) were determined. The initial total plate count varied between 3 × 105and 3 × 107and reached about 106– 107during processing or drying. Though there was an increase of about 2–4 log in the RSL of the product during smoking and/or drying there was no substantial change in pH (6.0–6.2 initial and 5.9–6.2 final). Under these conditions, there was little or no increase inS. aureus(BP) count during curing, smoking or drying of pepperoni. Smoking of pepperoni contributed substantially to the inhibition ofS. aureusgrowth because unsmoked product, under same conditions, showed a 1–2 log increase inS aureuswith method III. Even thoughS. aureusreached a population of 4 × 107/g in pepperoni processed without smoking by method III, detectable amounts of enterotoxins were not present in 100g. Pepperoni processed with smoking by either method is not likely to be a health hazard from stap

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00588.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTBones from six different anatomical locations of two young, two intermediate and two old bovine were used to characterize bone marrow lipids as a function of animal age and bone location with the view of utilizing these lipids for human consumption. Nonpolar lipids from bone marrow increased with increasing animal age. Oleate was the predominant fatty acid in both nonpolar and polar lipid fractions. There was a decrease in the unsaturated fatty acids in nonpolar and polar lipids from young to old bovine. As chronological age advanced the percent of triglycerides in bone increased while the percent of cholesterol esters, cholesterol, free fatty acids and diglycerides decreased. Some changes in lipids as a function of anatomical location were evident.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00589.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTThis study was initiated to explain the rare occurrence of bitter defects in goat and ewe cheeses, compared to cow cheeses. The main difference between whole caseins from these three species is their relative content of αS1‐ and β‐caseins. The tastes of enzymic hydrolysates (obtained with rennet, porcine pepsin, α‐chymotrypsin, trypsin and thermolysin) of whole caseins from these species were compared as well as those of cow αS1‐ and β‐caseins. In each case (except with chymotrypsin) the bitterness of hydrolysates from cow whole casein was much stronger than those of goat and ewe whole casein hydrolysates. Cow αS1‐casein hydrolysates were more bitter than cow β‐casein hydrolysates, exc

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00590.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTA Maillard complex of bovine serum albumin and D‐glucose was prepared by equilibrating a freeze‐dried mixture of the protein and sugar at 52% relative humidity followed by heating at 55°C for 18 hr. No visible brown pigmentation was observed in the resulting powder. An 80% reduction in free amino groups was measured during the heating period. Solutions of the protein and the protein‐sugar complex were heated for 30 min at temperatures ranging from 60–100°C. The heated albumin was insoluble at the isoelectric pH while the albumin‐glucose complex maintained solubility over a pH range of l‐7. Increases in levorotation due to heat treatment were similar for the protein and the protein‐sugar complex. These results indicate that the complexing of bovine serum albumin with D‐glucose increases the stability of the protein by protection against precipitation of the denatured molecules rather than protection against changes in inter

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00591.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTPre‐rigor dissected turkey muscles when heated in the rigor state had higher shear values than similarly heated rigor dissected controls. This difference was eliminated by aging. There was no difference in shear values between unaged and aged muscles which were dissected after rigor mortis. Chilling or freezing‐thawing either pre‐rigor or rigor dissected turkey muscles caused no increase in shear values. Aging these muscles produced no significant change in shear values. Turkey semi‐tendinosus muscle which entered rigor after pre‐rigor dissection had significantly higher shear values than the contralateral muscles which entered rigor in a stretched position. Aging for 7 days removed these differences in shear values. Shear values increased on heating unaged or aged (3 days) turkey pectoralis muscle between 50 and 100°C. The appearance of the curves for the unaged and aged muscles was similar. The effect of aging ovine muscles did not produce the same pronounced change in shear values that was obtained on the turk

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00592.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTCooking poultry meat with polyphosphates has been found to decrease the production of carbonyl volatiles. 2,4‐dinitrophenylhydrazine solution was used to trap carbonyl volatiles during oxidative cooking. Gas chromatography and mass spectrometry studies of the regenerated carbonyls indicated that there was no qualitative change in carbonyls obtained from polyphosphate‐treated samples as compared to those of controls. The carbonyls in cooked poultry meat were hexane extracted and analyzed as their 2,4‐dinitrophenylhydrazones. Partition column chromatographic data also showed that there was no qualitative difference in carbonyls of poultry meat cooked with or without polyphosphates. Addition of polyphosphates decreased dicarbonyls, methyl ketones and 2,4‐

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00593.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTThe ATP dissociation of natural actomyosin from chicken breast and leg muscle at 0 and 168 hr postmortem was studied by ultracentrifugal and viscometric methods. Superprecipitation behavior and ATPase activities were also examined. The results demonstrate that postmortem aging of muscle has no effect on the dissociation of actin and myosin, and are incompatible with the hypothesis that the actin‐myosin interaction undergoes a “weakening” during postmortem

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00594.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTA 30,000 dalton protein is produced from chicken muscle fibrils as a result of postmortem aging. The myofibrils of fresh muscle homogenates incubated at a temperature of 40°C for 4 hr at pH 5.4 also develop this band. Purified myofibrils treated in this manner show no changes in electrophoretic pattern. Changes in ATPase activities of myofibrils as a function of pH are unrelated to the development of the 30,000 band. Electrophoretic patterns of natural F‐actin prepared from aged muscle also exhibit a 30,000 band, suggesting that this band may be associated with thin filamen

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00595.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTElectrophoretic patterns of myofibrillar proteins and the ultrastructure of turkey breast muscle aged 0–48 hr were studied. Electrophoretic patterns indicated that protein aggregates were present in aged but not in unaged (0‐hr) muscle. Tropomyosin was present in 0‐hr muscle but not in muscle aged 3 hr or longer. General structural deterioration was noted as muscle aged. H‐zones were absent and M‐lines sometimes were displaced in transmission electron micrographs of post‐rigor muscle. Z‐lines lost their pre‐rigor density while corresponding transverse elements in scanning electron micrographs flattened during aging. Spaces developed between fibrils indicating loss of lateral attachments and breaks at the Z‐line were noted. Although protein and ultrastructural changes were limited, they possibly account for postmortem decreas

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00596.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACTPolychlorinated biphenyls in the environment may constitute a potential health hazard to edible fishery products, which are caught in polluted waters, and/or packaged in materials containing PCBs. Since many state and federal agencies are concerned with the toxicity of PCBs in seafoods, this project was designed to develop physical and chemical methods (ultraviolet radiation and treatment with sodium nitrite) for eliminating these compounds from shrimp. Shrimp were treated with 1% sodium nitrite solution followed by 100 ppm solution of Aroclor 1254 and Aroclor 1260, mixtures of PCB containing 54% and 60% chlorine respectively. A parallel experiment was performed without sodium nitrite pretreatment. All samples were analyzed after sun drying for 12, 24, 36 and 48 hr. PCBs were recovered by extraction, Florisil column cleanup and gas chromatography. Individual chlorinated biphenyls were identified by combined GC and MS. Complete reduction of PCBs was observed for both Aroclor 1254 and 1260 in sodium nitrite treated shrimp after 30 and 48 hr respectively. Untreated samples exhibited complete degradation after a lag of 6 and 12 hr respectively for each of the PCB mixtures. Pretreatment of shrimp with 1 % sodium nitrite considerably accelerated the reduction of PCBs. The rate of reduction was dependent on the percentage chlorine content of the PCB. Sun drying induced a stepwise reductive dechlorination with higher chlorinated biphenyls breaking to lower chlorinated biphenyls. The complete phenomena of degradation was presumed to be either one or a combination of reductive dechlorination, polymerization and isomerization processes. Since sun drying is a common practice in many parts of the world, this process could eliminate or reduce toxic polychlorinated biphenyls from seafoods.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1976.tb00597.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY