冷冻处理的熟制虾肉在保鲜条件下的货架期

以熟制克氏原螯虾(Procambarus clarkia)虾肉为原料,分别进行缓慢冷冻和快速冷冻处理后,于4℃下贮藏,通过感官评价、理化指标和微生物指标的测定,研究冷冻处理的熟制虾肉的货架期和品质。研究发现:快速冷冻处理虾肉的品质优于缓慢冷冻处理,但两者的货架期均为5d,6d为可接受的限值,未经冷冻处理的虾肉货架期为2d。感官评分值与TVB-N,MDA含量和菌落总数均有极显著的负相关,R2均在-0.947以上(P<0.01)。快速冷冻组虾肉在贮藏期间失重率和pH值稳定。TVB-N和菌落总数有望作为评价熟制虾肉品质的化学指标,TVB-N值为30mg/100g和菌落总数为6logcfu/g可作为熟制虾肉可接受的限值。冷冻处理有效的延长了熟制虾肉在4℃贮藏条件的货架期,可作为一种处理手段应用于熟制水产品的保鲜。     

Quality characteristics of fresh blue crab meat held at 0 and 4 degrees C in tamper-evident containers.

There has been a regulatory movement toward the required use of tamper-evident containers for fresh blue crab meat. North Carolina passed tamper-evident regulations in 1993. Blue crab processors had little information on possible changes in head-space gases, microbial growth, chemical decomposition, sensory quality, or shelf life caused by the new containers. Chemical, microbiological, physical, and sensory changes in fresh crab meat were monitored during 18 days of storage in ice and 13 days of storage refrigerated at 4 degrees C. "Special" blue crab meat, chosen for the study, is the least expensive commercial form of white crab meat. The crab meat was packaged in four retail containers: copolymer polyethylene cups with polyethylene snap-on lids, copolymer polyethylene cups with snap-on polyethylene lids fastened to the cup with heat-shrink low-density polypropylene seals, copolymer polyethylene cans with aluminum easy-open ends, and copolymer polypropylene cups with a tamper-evident pull-tab on the lid. Control samples packaged in industry standard copolymer polyethylene cups maintained higher oxygen levels than meat stored in tamper-evident containers. No consistent differences in quality or shelf life were detected among the containers. Market shelf life was limited to 6 days for meat held at 4 degrees C and 15 days for meat held at 0 degrees C. Sensory quality deteriorated 6 days earlier for crab meat held at 4 degrees C than meat held at 0 degrees C. Collateral work showed that toxin production by Clostridium botulinum neither occurred following 18 days of storage at 4 degrees C nor after 15 days of storage at 10 degrees C. Definite spoilage occurred before any toxin production. The study suggests that blue crab processors can safely use the new tamper-evident packaging, which has little or no effect on product quality or shelf life. Processors may choose appropriate packaging options using price, packaging quality, market appearance, and ease of production as the deciding criteria.     

Effect of Heat Processing in Cans and Retort Pouches on Sensory Properties of Fowl Meat

Fowl meat processed in cans and flexible retortable pouches was evaluated for heat effects on sensory properties. A trained panel evaluated texture and off-flavor of canned boned chicken, uncooked fowl meat retorted in flexible pouches, cooked meat retorted in flexible pouches, and simmered fowl meat (control). Results indicated that the retort pouch process may offer a method for improving the texture of processed fowl meat from spent hens by adequately cooking to tenderize the meat but not overcooking it to the extent that meat chunks are reduced to fibrous, shredded, or stringy components. Off-flavor development was related to pre-cooking before retorting.     

THE AROMA OF CANNED BEEF: PROCESSING AND FORMULATION ASPECTS

The influence of processing techniques and formulations on chemical and sensory aroma properties has been studied with the purpose of finding ways to improve the flavor of canned meat. HTST-sterilization, "aseptic" canning and sterilization in various packaging materials including flexible pouches have been investigated. It was found that "aseptic" canning and, especially, HTST-sterilization had a pronounced positive effect on aroma, in the latter case for samples packed in thin layers (flexible pouches). It was shown that addition of e.g., fumarate or maleate in small amounts (0.06–0.15%) before sterilization decreased the concentrations of hydrogen sulfide and mercaptans, and the additions of certain amino acids, e.g., arginine, decreased the concentrations of the aldehydes. Both types of ingredients resulted in an improved aroma. Storage changes have also been investigated. It was found that there was a tendency towards a more accelerated change in flexible pouches compared with rigid cans.     

Comparison of the quality and storage stability of salmon packaged in various retort pouches

The effect of thin metal oxide coated barrier materials on the quality of shelf stable salmon was investigated. Four different retort pouch structures were used: Cast polypropylene (CPP); polyethylene terephthalate (PET)/silicon oxide-coated nylon/CPP (SIOX); Aluminum oxide-coated PET/nylon/CPP (ALOX); PET/aluminum foil/CPP (FOIL). To determine the amount of lipid oxidation in the salmon, thiobarbituric acid reactive substance (TBARS) was measured. Salmon packaged in SIOX pouches had higher TBARS value, 43.53 mili-extinction/g, than salmon packaged in FOIL pouches, 37.06 mili-extinction/g, after 8 weeks of storage. A multiple comparisons test was used to evaluate the sensory characteristics of the salmon. Salmon packaged in SIOX pouches had less acceptability, 4.11, than salmon packaged in FOIL pouches, 5.44, after week 8. Conversely, salmon packaged in ALOX pouches had similar sensory and TBARS value with salmon packaged in FOIL pouches. The barrier properties of each pouch material were also investigated. Oxygen permeability (OP, g μm/m² day kPa) of SIOX increased from 0.88 to 10.55 after retort processing. SIOX had an OP of 10.94 at week 8 while ALOX and FOIL had 0.51 and 0.47 of OP, respectively. Overall, shelf stable salmon packaged in ALOX had a shelf life comparable to salmon packaged in a traditional FOIL pouch material, while salmon packaged in SIOX had a significantly lower shelf life then either ALOX or FOIL.     

Effect of storage temperature and packaging on quality and shelf‐life of high pressure processed black tiger shrimp (Penaeus monodon)

The effect of high pressure processing (361 MPa/12 min/46 °C) on the quality and shelf‐life of black tiger shrimp was investigated. Changes in physical, biochemical, microbiological, and sensory attributes of samples packed in low density polyethylene (LDPE), ethylene vinyl alcohol (EVOH), and multilayer metalized polyester (MMP) pouches were examined during storage at 4, 15, and 25 °C for 30 days. The estimated shelf‐life of pressure treated samples based on sensory, chemical, and microbiological data was found to be 30 days for EVOH and MMP samples and 18 days for LDPE samples at 4 °C. The control and high pressure samples at 15 °C reach the unacceptable limit by 3rd and 9th day of storage, respectively. However, the samples at 25 °C showed shelf‐life of less than 3 days. Among the packages employed in the study, EVOH film was adjudged to be best in maintaining the quality of shrimp.

Practical applications

In global seafood market, shrimp is a commercially traded important commodity. The conducted study detailed about the quality changes occurred due to microbial activity and biochemical reactions in high pressure processed black tiger shrimp under different storage and packaging conditions and their impact on the shelf‐life. The provided data will be useful in the selection of appropriate conditions to preserve the valuable catch, establish high quality and safety requirements to enhance the marketing potential of shrimp.     

Effect of Heat Processing on the Texture Profile of Canned and Retort Pouch Packed Oil Sardine (Sardinella longiceps) in Oil Medium

ABSTRACT: Sardine in oil was canned at 3 different Lethality values (F₀ 5,7, and 9) in retort pouches and aluminum cans in stationary retort. Process time calculations were done mathematically to find out the actual process time. Sardine in oil processed in retort pouches had a lower process time compared with aluminum cans for each F₀ value. Instrumental texture analysis was done using a food texture analyzer to study the effect of thermal processing on the texture of thermally processed sardine in oil in aluminum cans and retort pouches. As the F₀ value and cook value increased in both the retort pouches and aluminum cans, the textural properties showed a decreasing trend. Hardness of the product canned in both aluminum cans and retort pouches decreased with increase in F₀ values.     

不同气调包装对熟制蟹肉蟹黄贮藏品质的影响

熟制蟹肉蟹黄由于蛋白质和脂肪含量较高,暴露在空气中极易被氧化,腐败变质,使货架期大大缩短,严重限制了产品生产和销售规模.本文以熟制蟹肉蟹黄为研究对象,探讨不同气调包装方式(空气,60％C02+40％N2和40％C02+60％N2)在4 ℃:贮藏条件下对其品质的影响,分析风味物质变化规律和货架期,最后确定产品最优气调包装...     

Effect of different binders on the quality of enrobed buffalo meat cutlets and their shelf life at refrigeration storage (4±1°C)

To enhance the binding and quality of enrobed buffalo meat cutlets (EBMC), a meat emulsion at 0%, 15%, 20% and 25% replaced the cooked meat in the formulation. Emulsion containing products had significantly higher moisture contents and texture scores compared to the control. Emulsion at 20% level could be incorporated in enrobed buffalo meat cutlets to enhance their quality. Addition of 1% egg white powder improved the quality of EBMC compared to control, while a 3% level had adverse effect on the sensory attributes despite giving higher product yield and lower shrinkage. Cutlets with refined wheat flour had significantly higher protein and fat contents. It had also higher acceptability followed by corn flour, potato starch and tapioca flour. TBARS of enrobed samples remained lower than controls throughout the storage period. Mesophilic count remained below log3cfu/g for both samples during storage. Uncoated products and enrobed products were acceptable up to 10th and 15th day, respectively. Enrobing of buffalo meat cutlets improved their acceptability and shelf life under refrigeration storage.     

Extension of Shelf Life by Treatment with Allyl Isothiocyanate in Combination with Acetic Acid on Cooked Rice

ABSTRACT: In order to extend the shelf life of cooked rice, allyl isothiocyanate (AIT) and acetic acid were applied, and both microbiological evaluations and sensory evaluations were performed during storage at various temperatures. The residual AIT concentration in the headspace of a cooked rice pack was also quantified. Total aerobic populations at various storage temperatures were lower where acetic acid alone or in combination with AIT were used. A sensory evaluation showed that the acceptability of cooked rice was influenced by the type of treatment. The antimicrobial effect of acetic acid in combination with AIT was excellent, so it seemed to have potential as an agent to extend the shelf life of cooked rice.     

Influence of low dose irradiation on the quality of fresh buffalo meat stored at 0-3°C

The effect of low dose irradiation on the microbiological, chemical and sensory qualities of fresh buffalo meat stored at 0-3°C was studied. Meat slices packed in polyethylene bags subjected to 2·5 kGy dose had a shelf-life of 4 weeks with acceptable sensory score, low total volatile basic nitrogen values and remarkable improvement in microbiological quality. Irradiated meat was completely free of Pseudomonas spp. and Enterobacteriaceae throughout storage. In contrast, the unirradiated control meat spoiled within 2 weeks.     

The effect of chitosan coating incorporated with ethanolic extract of propolis on the quality of refrigerated chicken fillet

Chitosan is considered as a functional packaging component for maintaining the quality and increasing the shelf life of perishable foods include meat, poultry, fish, dairy products, and all cooked leftovers. The present study was conducted to evaluate edible coating of chitosan (2%) containing ethanolic extract of propolis (1% and 2%) on microbiological (mesophilic aerobic, psychrotrophic, lactic acid bacteria, coliforms, and Staphylococcus aureus counts), chemical (TBARS, TVN and Peroxide values) and sensory (odor, color, texture, taste, and overall acceptance) properties of chicken fillet. Microbial analysis showed that coating had a significant reducing effect on growth of bacteria during 12 days at 4 °C. Besides, the increase of TBARS, Total volatile nitrogen, and peroxide value of samples coated by chitosan and ethanolic extract of propolis was less than control group. According to our results, chitosan and propolis can be used to enhance the shelf life of fillet and maintain its quality.

Practical applications

Propolis is used for infections caused by bacteria, viruses, fungus, and by single‐celled organisms called protozoans. Propolis is also used as an antioxidant and anti‐inflammatory agent. Ethanol extract of propolis improve the properties of chitosan edible coating in chicken fillet preservation. The chitosan coating incorporated with ethanolic extract of propolis can improve the microbial, chemical, and sensory quality of food and enhance the shelf life of them by synergistic effects.     

Comparison of the shelf lifes of map and vacuum packaged hot smoked rainbow trout (Onchoryncus mykiss)

The objective of this study was to determine the differences of microbiological and chemical quality in MAP and VP packages in refrigerated smoked trout fillets. Such information is important in evaluating the safety of these products. Three groups were constituted: group A – packed in 60%Co₂/40% N₂; group B – packed in 50%CO₂/50% N₂ and group C– vacuum packed. The ratio of fillet to package volume was 1/3 chemical analysis and microbiological analysis were done and also instrumental and sensory analysis were used to determined the shelf life. The observed shelf life of smoked trout was found at least 33 days in vacuum package, 47 days in 60% CO₂/40% N₂ gas mixture and 40 days in 50% CO₂/50% N₂ gas mixture according to results of microbiological analysis. The observed shelf life of smoked trout in MAP group A was determined as 14 days more than VP packs according to results of microbiological and sensory analysis in the study.     

Shelf life of modified atmosphere packed cooked meat products: addition of Na-lactate as a fourth shelf life determinative factor in a model and product validation

Cooked meat products are often post-contaminated because of a packaging and/or slicing step after the pasteurisation process. The shelf life is therefore limited and can be extended by adding Na-lactate. A previously developed model for the spoilage of gas packed cooked meat products, including temperature, water activity and dissolved CO2 as independent variables, was extended with a fourth factor: the Na-lactate concentration in the aqueous phase of the meat product. Models were developed for the maximum specific growth rate mu(max) and the lag phase lambda of the specific spoilage organism Lactobacillus sake subsp. carnosum. Quadratic response surface equations were compared with extended Ratkowsky models. In general, response surface equations fitted the experimental data best but in the case of mu(max) the response surface model predicted illogical growth behaviour at low water activities and high Na-lactate concentrations. A extensive product validation of the mathematical models was performed by means of inoculated as well as naturally contaminated industrially prepared cooked meat products. The deviations of the experimentally determined versus predicted growth parameters in inoculated cooked meat products were in general small. Both types of models were also able to predict the shelf life of naturally contaminated cooked meat products, except for paté where an under-estimation of the shelf life was predicted by the response surface equations. The validation studies revealed higher accuracy of the extended Ratkowsky models in comparison to the response surface equations. A significant shelf life extending effect of Na-lactate was predicted, which was more pronounced at low refrigerated temperatures. A synergistic effect has also been noticed between Na-lactate and carbon dioxide which, at least partly, could be explained by the pH-decreasing effect of CO2.     

Quality changes during superchilled storage of pork roast

Quality parameters (sensory, physical, biochemical and microbiological) of superchilled vacuum packed boneless pork roasts were studied during storage for 16 weeks. Superchilling of vacuum packed pork roast at a temperature of −2.0 °C improved shelf life significantly compared to traditional chilled storage at +3.5 °C. Superchilled pork roasts maintained good sensory quality and low microbiological counts during the whole storage period. The drip loss in superchilled samples was lower and showed less variation than in the references and the temperature abused roasts. The consequences of an interrupted cold chain during storage were also investigated. Superchilled samples with temperature abuse resembled chilled samples with respect to drip loss and microbial levels. To take advantage of all the benefits of superchilling and successfully implement the process in the food industry a stable, controlled temperature during storage is critical.     

Shelf life establishment of a sliced, cooked, cured meat product based on quality and safety determinants

In the present study, the distribution of the shelf life of cooked, cured meat products based on lactic acid bacteria growth and the distribution of the time to cause health risks based on Listeria monocytogenes growth were studied. Growth models, developed and validated on cooked meat products, were used to predict the growth of microorganisms. Temperature data were obtained from retail and home refrigerators. Distribution predictions were conducted by two approaches (time-temperature profiles and Monte Carlo simulation). Time-temperature profiles were more appropriate to be used, because Monte Carlo simulation overestimated the growth of L. monocytogenes. Shelf life was greatly influenced by storage temperature, but initial microbial load had a smaller effect. The expiration date of cooked meat products might be based on only the growth of the spoilage microorganisms, and only when product contamination with L. monocytogenes cell concentrations is high does a product fraction pose health risks for consumers. Sensitivity analysis confirmed that storage temperature and temperature variability were the most important factors for the duration of shelf life. Distributions of shelf life and time to cause health risks give valuable information on the quality and safety of cooked meat products and may be used as practical tools by meat processors.     

Lethality and quality evaluation of in-packaged ready-to-eat cooked Jasmine rice subjected to industrial continuous microwave pasteurization

The use of the pasteurization unit as a measure of the lethal effect of heating processes and overall quality of ready-to-eat Jasmine rice was determined in order to compare the conventional and microwave technology. Cooked Jasmine rice was packed in a polypropylene plastic cup and sealed with a lidding film, then subjected to a continuous microwave system (eight 800 W; 2450 MHz) and conventional steamer. The pasteurization unit, log reduction, microorganism count, color, instrumental textural property, and sensory attributes were investigated over a 30-day storage at 8°C. The pasteurization process time was reduced from 420 s under the conventional process to 216 s under the microwave process for a 5-log reduction of L. monocytogenes. The microwave heating showed greater effectiveness for shelf life, extending the product from 7 days (conventional) to 30 days. Cooked rice after heating by microwave was whiter and showed lower hardness than the conventional heated sample. Throughout storage, sensory attributes of the pasteurized product heated by microwave were acceptable by panelists. The addition of 15% trehalose or 1% soybean oil into the rice before cooking decreased the hardness of the cooked rice during storage. This study successfully demonstrated that the continuous microwave pasteurization process, compared to the conventional process, required less process time for ready-to-eat cooked Jasmine rice and extended the shelf life while providing better product quality.     

Characterisation of oregano water extracts and their effect on the quality characteristics of cooked pork

The present study characterises oregano water extracts and reports their effects on the shelf life and quality characteristics of cooked pork. Some changes in oregano extract taking place during its thermal treatment were observed. The main volatile compound in the unheated and heated extracts was carvacrol; however, the second major constituent in the unheated extract β-caryophyllene was absent in the heated one. Colour changes during heating were characterised by an International Commission on Illumination (CIE L a b) method. The heated extract better scavenged 1,1-diphenyl-2-picryl hydrazyl radicals, most likely owing to the formation of stronger radical-scavenging derivatives during thermal treatment. The effect of oregano extracts on the shelf life and colour characteristics of stored meat samples in most cases was not significant; however, sensory assessment clearly showed that the addition of extracts had some negative influence on meat flavour and colour.     

Shelf Life Determination of Sliced Portuguese Traditional Blood Sausage—Morcela de Arroz de Monchique through Microbiological Challenge and Consumer Test

Morcela de Arroz (MA) is a ready‐to‐eat blood and rice cooked sausage produced with pork, blood, rice, and seasonings, stuffed in natural casing and cooked above 90 °C/30 min. It is commercialized whole, not packed, with a restricted shelf life (1 wk/0 to 5 °C). The objective of this work was to establish sliced MA shelf life considering both the behavior of L. monocytogenes through a microbiological challenge test (MCT) and the consumer acceptability of MA stored: vacuum packed (VP), modified atmosphere packed (MAP: 80% CO₂/20% N₂), and aerobic packed (AP). The MCT was conducted inoculating ±3 log CFU/g of L. monocytogenes cell suspension on the MA slices. Packaged samples were stored at 3 ± 1 °C and 7 ± 1 °C until 20 d. At 3 ± 1 °C, L. monocytogenes behavior was not affected by packaging or storage time. At 7 ± 1 °C, the pathogen increased nearly 1 log CFU/g in the first 4 d. L. monocytogenes populations in AP were higher (P < 0.05) than in MAP. The pathogen may grow to hazardous levels in the 1st days if a temperature abuse occurs. Considering the acceptability by the consumers, the shelf life of MA stored at 3 ± 1 °C was 4.4 d for AP, 8.1 d for VP, and 10.4 d for MAP. The sensory shelf life established based on sensory spoilage is shorter than the shelf life to maintain the population of L. monocytogenes in safe levels.     

Oxidative stability and dietary treatment with vitamin E, oleic acid and copper of fresh and cooked pork chops

Research has been conducted on the effects of feed supplementation with vitamin E, oleic acid (sunflower oil) and copper on some quality characteristics of pork chops. The study was based on the measurement of pH 45' and 24 hr post mortem, proximate composition, colour both objective and sensory, colour stability after packing in oxygen permeable film and protective atmosphere, copper and iron contents, vitamin E content in fresh and cooked chops, peroxide and TBARS value in raw and cooked meat, total cholesterol, cholesterol oxides and aldehydes in cooked meat, sensory evaluation of the eating quality of cooked chops and iodine number of subcutaneous fat. Vitamin E content was significantly higher with oil and vitamin supplementation. No variation has been observed in copper and iron contents. A higher stability of the colour of meat packed under modified atmosphere has been observed with increasing vitamin E content, but the same did not apply with meat packed in oxygen permeable film. No differences have been observed on fatty acid oxidative stability of fresh m. longissimus dorsi and cooked chops (peroxide and TBARS values), on cholesterol oxidation and aldehydes production of cooked chops with increasing vitamin E content. Iodine number in supplemented animals reached levels normally considered at risk for fat firmness.