摘要:

ABSTRACTSeveral species of land snails, includingHelix pomatiaandHelix lucorumare consumed as food products. The main source of commercial competition is an imported African snail,Achatina fulica. The only way to distinguish between these species has been morphologically. We hypothesized a reliable method for identifying canned snails could be based on using PCR‐RFLP analysis of mito‐chondrial DNA. The molecular weights of the amplified fragments were perfectly identical, regardless of low extraction (fresh snails or cooked and canned samples). The whole amplified products (16S rRNA and 12S rRNA) made it possible to check any fraudulent label and identify the three species using four restriction enzymes (RF

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14712.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTGround beef patties were cooked to 63, 66, 68 and 71°C and 25g meat from the center of each patty was extracted. Changes in protein composition of extracts were monitored by sodium dodecyl sulfate‐polya‐crylamide gel electrophoresis, Western blotting and enzyme activity. Acid phosphatase, bovine serum albumin, glyceraldehyde‐3‐phosphate dehydrogenase, lactate dehydrogenase, phosphoglycerate mutase, and tri‐ose phosphate isomerase concentration or activity decreased (P<0.05) as endpoint temperatures increased. None of the enzymes was completely inactivated or insolubilized at 71°C. These proteins might be useful in assays to verify processing temperatures of ground b

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14713.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTBeef and pork longissimus dorsi and semimembranosus muscles and chicken breast and thigh muscles were excised 24 hr postmortem from carcasses of marketweight grain‐finished feedlot beef cattle, marke‐tweight hogs on a typical finishing diet, and broilers on a commercial grain diet. Muscle samples were immediately ground and formed into patties and stored raw or after cooking, at 4°C (cooked) or −20°C (raw and cooked). TBA values (on sample weight basis) of frozen raw samples were higher for beef and pork than for chicken, as was heme iron content. However, TBA values of cooked samples were highest for chicken thigh muscles, which contained the most polyunsaturated fatty acids, at all storage tempe

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14714.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThe effect of biogenic polyamines (agmatine, cadaverine, putrescine, spermidine, and spermine) on the activity of pork muscle aminopeptidase and alanyl aminopeptidase was investigated. Agmatine (5 mM) showed a powerful inhibitory effect for both enzymes (more than 50% inhibition). Cadaverine and less intensely putrescine showed similar inhibitory effects for both enzymes. All assayed polyamines inhibited activity of both aminopeptidases except spermine and spermidine which did not affect aminopeptidase B. Thus, one of these inhibitors could be used to avoid the interference of alanyl aminopeptidase when assaying aminopeptidase B in muscle extracts.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14715.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThe effects of feeding menhaden, flax, palm, or sunflower oils with to‐copherols to laying hens on the internal quality of eggs during 40‐days storage were examined. Dietary tocopherols increased (P<0.05) the tocopherol content of eggs. Addition of tocopherols increased (P<0.05) the Haugh unit at 40‐days storage in menhaden, flax, and palm oil eggs. Dietary tocopherols increased (P<0.05) the content of 20:5 n‐3 and 22:6 n‐3 in menhaden oil eggs. At 40‐days storage, the TBA values in menhaden oil eggs were reduced (P<0.05) by dietary tocopherols. Storage decreased (P<0.05) 8‐tocopherol in the flax and sunflower oil eggs. Yolk pH increased during sto

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14716.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTComparisons were made with native egg yolk, dried egg yolk and a commercial yolk substitute (soy lecithin). Aqueous emulsions were prepared by sonicating water containing 0–5% NaCl, 20% peanut oil, HC1 or NaOH as needed for pH adjustment, and 1–3% emulsifier expressed as the total of phospholipids, glycolipids and proteins contributed by yolk ingredients or soy lecithin. The median diameters of fat particles in the emulsions with and without dispersing fat droplet floes using Triton X‐100, were evaluated by laser light diffraction. The emulsifying properties of low‐fat, low‐cholesterol egg yolk were similar to or better than those of native yolk and dried egg yolk. Soy lecithin had less effective emulsifying properties than yolk ingredients with respect to coalescence of fat droplets during storage and separation during 70°C

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14717.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTCalcium soaps of high oleic sunflower oil (HOS‐Ca) were prepared, using alkaline hydrolysis and calcium precipitation, and freeze‐dried. Cows’ diets were prepared to provide 0, 0.85 kg or 1.7 kg HOS‐Ca/day. Fatty acids and cholesterol were determined by gas chromatography. Sensory evaluations of milk from cows fed 0 and 1.7 kg HOS‐Ca/day were conducted using triangle tests. The 18:lco9 concentration in milk from cows fed the 1.7 kg HOS‐Ca diet increased from 22.9 to 35.2% compared to the control (p<0.05). Concentration of total medium‐chain saturates (C12‐C16) decreased from 40.7 to 31.4% (p<0.05). Feeding HOS‐Ca resulted in increases of monoene fatty acids and lower medium‐chain saturated fatty acids but no ch

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14718.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTProtein coverage, composition and structure of surface layers of fat globules in recombined milk were determined. Average protein load was ∼6 mg/m2fat surface. Both casein and whey proteins were present in the fat globule surface layer, with casein adsorbed in preference to whey proteins and αs(αsl+αs2)‐casein adsorbed in preference to β‐casein. Transmission electron microscopy showed that the surface layer of fat globule was made up of casein micelles, fragments of casein micelles and a thin layer of protein, possibly whey proteins. Experiments with surface layers that had been dispersed in EDTA showed that the extent of dissociation of caseins followed the order: β‐casein>αs‐casein ≦ K‐casein, suggesting that most of the K‐casein was probably associated directly

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14719.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTButterfat was hydrolyzed with lipases contained in lecithin reverse micelles. The influence of pH, temperature, molar ratio of surfactant to water (R) and surfactant concentration on the hydrolytic reaction indicated linear, quadratic, and interactive effects for reaction systems mediated byR. javanicusandC. rugosalipases. The initial reaction rate was dependent on reaction parameters; however, the degree of hydrolysis was independent of pH. Both enzymes exhibited high thermal stability. The content and composition of milk fat hydrolysates prepared byR. javanicuslipase were most influenced by reaction temperature and R. The optimum conditions for production of free fatty acids, monoacyl‐glycerols, diacylglycerols and specific regio‐isomers were defi

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14720.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThe chemical stability was studied on anhydrous milkfat (AMF) encapsulated in whey protein isolate (WPI) and WPI combined with lactose (1:1 w/w WPI/L). AMF‐containing microcapsules, as well as bulk milkfat, were stored at 20°C with light, 40°C without light, and 50°C with and without light for up to 12 mo. Milkfat oxidation was monitored by oxygen uptake in headspace and hexanal accumulation. In all cases, AMF oxidation was significantly limited by microencapsulation in WPI or WPI/L. Whey proteins are effective microencapsulating ag

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1996.tb14721.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY