摘要:

ABSTRACTIndividually frozen, scaled whitefish (Coregonus clupeaformis) rapidly developed oxidative off‐flavors when stored without packaging at −12°C, but both vacuum‐packaging in barrier films and ice‐glazing significantly suppressed the development of oxidized flavors through 24 wk of storage. Removal of scales prior to freezing significantly enhanced the development of oxidized flavors over unscaled whitefish when both were held unprotected at −12°C. Loose‐packaging of individual, well‐washed whitefish in closed polyethylene pouches significantly improved oxidative stability compared to those stored unprotected. However, vacuum, barrier‐film packaging gave significantly better protection than polyethylene at both −12°C and −25°C through 24 wk

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13264.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTVolatile compounds which contribute to the distinct melon‐like aroma of fresh Pacific oysters (Crassostrea gigas) were identified as (E,Z)‐2,6‐nonadienal and 3,6‐nonadien‐1‐ol, but these compounds were not found in the less intensely flavored Atlantic oysters (Crassostrea virginica). 1‐Octen‐3‐one, 1‐octen‐3‐ol, 1,5‐octadien‐3‐one, 1,5‐octadien‐3‐ol, and 2,5‐octadien‐1‐ol were found in both species of oysters, and contributed a characteristic heavy, planty aroma to each. Sensory panel scores for intensity of fresh melon‐like flavors were significantly higher for both raw and steamed Pacific oysters than for comparable Atlantic oysters. Enzymic generation of alcohols and carbonyls that comprise the characterizing aroma compounds from polyunsaturated fatty acids was demonstrated by preventing their formation with specific inhibitors for cyclooxygenase (acetylsalicylic

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13265.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTDifferential scanning calorimetry (DSC) was used to investigate thermal transitions of fish mince (surimi) and actomyosin from croaker. Three endothermic peaks were observed in DSC thermograms of surimi. After addition of salt, transition temperatures shifted to lower temperatures. Preheating samples containing 3% salt at various temperatures showed that 40°C heating caused the first peak to disappear, and preheating at temperatures higher than 50°C caused virtual disappearance of all transition peaks. Low temperature storage (4°C) of samples caused no significant change in thermograms of salted or unsalted surimi over a 5‐day storage period. Evidence suggests that changes of fish protein during low temperature “setting” are different from those occurring during high temperature

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13266.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTTwo types of thermal scanning rigidity monitors (TSRM) were developed which are nondestructive and capable of monitoring rigidity or viscosity changes during heating of proteins over a wide range of concentrations. Thermal transitions which occur during gelation of croaker actomyosin were studied by these TSRM devices and the Brookfield viscometer during constant rate heating (1°C/min). Gelation of actomyosin occurred only at protein concentrations above 5.5% under these conditions. In plots of rigidity versus temperature, three transitions were observed during gelation, occurring near 38°C 46°C and 60°C. At lower concentrations, only one peak was observed, occurring near 36°C. A relationship between the 36–38°C transition in rheological properties and the high temperature “setting” phenomenon of fish proteins is

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13267.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe thermal transitions of starch‐fish protein mixtures were investigated by a thermal scanning rigidity monitor technique and differential scanning calorimetry. Three transitions due to protein denaturation and one transition due to starch gelatinization were identified by both techniques during thermal processing of these mixtures. The gelatinization of starch caused an increase in rigidity of the system to a degree dependent upon the starch type. Thermal transitions of starch and fish protein seemed to proceed independently in mixture systems. However, the presence of salt and sucrose, necessitated by the inclusion of fish protein, caused starch gelatinization to shift to higher temperature

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13268.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTA high performance liquid chromatographic (HPLC) procedure for determination of the toxins associated with paralytic shellfish poisoning (PSP) is compared to the standard AOAC mouse bioassay method on 100 shellfish samples representing a variety of species. For those samples with toxin content below the detection limit of the bioassay (35 μg saxitoxin (STX)/100g) HPLC analysis indicated a similar low level with a range of35 μg STX/100g). Among the advantages of the HPLC method over the bioassay are significantly better sensitivity, greater sample through‐put, and ability to determine the levels of each individual PSP t

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13269.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTIndividual optical fibers in a coherent light guide were used to measure the color of small inclusions such as meat fragments, pepper corns and herb leaves in processed meat products. With an optically homogeneous product (liver pate), the absorbance spectrum with coherent fiber optics was similar to that obtained with a noncoherent system. With an optically anisotropic myosystem (ham), differences were found between 600 and 700 nm. In variegated meat products (meat loaf and bologna), variance in the integrated spectrum was related to divergence between the focal spectra of the meat inclusions and the surrounding matrix, but meat‐fragment size also had an effect on varianc

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13270.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe effects of rotenone and pH on color of pre‐rigor muscle homogenates were determined by use of the Hunter Color Difference Meter and by visual appraisal. Both rotenone and low pH treatment led to development of bright red color in pre‐rigor beef muscle homogenates. Both effects are probably due to mitochondrial inhibition or inactivation, so that myoglobin remains oxygenated in presence of air. It is concluded that dark color of pre‐rigor muscle is due to oxygen consumption by actively respiring mitochondria at muscle surfaces, keeping myoglobin deoxygenated. It is likely that dark color associated with heat ring defect and dark cutting meat is also related to active mitochondrial respir

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13271.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTTaste panel, Warner‐Bratzler shear force (WBS) and cooking loss characteristics of semimembranosus (SM) muscles from thirty electrically stimulated and hot‐boned (ESHB) or control young bull sides were evaluated. At 2 hr postmortem, muscles were excised from electrically stimulated sides and chilled in a tray or in a cardboard box. All control sides and ESHB muscles were chilled at 5–7°C until 24 hr postmortem; then 2–4°C for 24 hr. At 48 hr postmortem, steaks were cut, vacuum packaged and aged (2–4°C) for 4 days. Beef flavor was more intense for control steaks than for steaks from either ESHB chilling treatment. No other difference

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13272.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTAdvanced myofibrillar degeneration with changes of I‐bands and Z‐discs was noted in electrically stimulated samples as early as the day of slaughter. Occurrence of the proteolytic changes observed paralleled rate of depletion of muscle energy stores during electrical stimulation and subsequent improvements in tenderness. Localized supercontractions have been implicated as one cause of improved tenderness of electrically stimulated bovine carcasses, as has enhancement of autolytic proteolysis. Contracture bands occurred in both nonstimulated and electrically stimulated samples in the early postmortem period. Contracture bands are a common artefact in improperly prepared tissue preparations, therefore they are not a specific effect of electrical stimulation. Improved tenderness of ES samples could more easily be explained by an accelerated autolytic proteoly

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1985.tb13273.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY