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Lower L (lower + l)
Selected AbstractsColour improvement of common carp (Cyprinus carpio) fillets by hydrogen peroxide for surimi productionINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2008Ali Jafarpour Summary The preferred colour for surimi is white, but surimi prepared from light fillets of common carp (Cyprinus carpio) is slightly pink. Hydrogen peroxide (H2O2; 1,3% v/v) with and without sodium tri-polyphosphate (STP; 1,2% w/v) was added to a sodium carbonate bath (pH 7.0,11.5) resulting in a final pH range of 4.4,10.1 which was injected into carp fillets. After soaking and tumbling for 30 min at 4,10 °C, the fillets were evaluated for colour and water holding capacity (WHC). Fillets tumbled with treatment solution with different pH levels (7.0,11.5), but with no H2O2 or STP added, had improved colour with significantly (P < 0.05) higher L* compared with untreated fillets as the control. However, the colour improvement [(L* and colour deviation (,E)] was not significantly different (P > 0.05) within the pH levels (7.0,11.5) trialled. With increasing H2O2 levels (1,3%), fillets became lighter and ,E increased significantly (P < 0.05), especially with a 3% H2O2 treatment at pH of 10.5 (adjusted pH before H2O2 addition, actual pH after H2O2 addition was 8.2). The whiteness (L*,3b*) of kamaboko produced from treated (3% H2O2, pH 10.5) common carp light fillets was not significantly different to that of kamaboko from Alaska pollock and threadfin bream. Treatments combining H2O2 (3%) with STP (1,2%) significantly reduced the L* value obtained in comparison with fillets treated with only H2O2 (3%). Similarly, fillets treated with STP (1%) alone, resulting in lower L* values, irrespective of treatment pH (7.0,11.5). WHC, an indicator of the quality of the fillet texture, increased from 816 g/kg at pH 7.0 without STP to 841 g/kg at pH 11.5 with 1% STP. Treatment with H2O2 (without STP) decreased the WHC of the fillets. [source] Comparative effect of red yeast rice (Monascus purpureus), red beet root (Beta vulgaris) and betanin (E-162) on colour and consumer acceptability of fresh pork sausages packaged in a modified atmosphereJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 4 2006Luis Martínez Abstract Fresh pork sausages containing natural colorants, red yeast rice powder (Monascus purpureus; Frame®) or a crude red beet root (Beta vulgaris) juice or commercial betanin (E-162), at different concentrations, were packaged in an atmosphere containing 80% O2 and 20% CO2 and stored in the dark for 20 days. The following parameters were measured at 4 day intervals: instrumental colour (CIE L*, a*, b*, a*/b*, C* and h*), reflectance spectra, sensory discoloration (trained panel) and acceptability and willingness to purchase (habitual and non-habitual consumer panels) under two different lighting displays (standard fluorescent and Promolux® lamp). The use of colorants improved the colour properties of fresh pork sausages. Sausages with red yeast rice, red beet root juice and betanin had lower L* and h* and higher a* and a*/b* values than control samples. The colour properties of sausages with red beet root were the closest to control sausages, while sausages with red yeast rice had significantly lower b* values. Both natural colorants and betanin protected sausages from discoloration and extended acceptability and willingness to purchase by about 4 days, according to evaluation by habitual consumers under two different types of lighting display. Therefore, red beet root juice may be envisaged as the most suitable natural colorant for use in fresh pork sausages. Copyright © 2005 Society of Chemical Industry [source] Microwave-Assisted Synthesis of PLLA-PEG-PLLA Triblock CopolymersMACROMOLECULAR RAPID COMMUNICATIONS, Issue 4 2007Chao Zhang Abstract Poly(L -lactide)- block -poly(ethylene glycol)- block -poly(L -lactide) (PLLA-PEG-PLLA) triblock copolymers were synthesized effectively by poly(ethylene glycol) initiated ring-opening polymerization (ROP) of L -lactide under microwave irradiation. The products were characterized by 1H NMR, GPC, and DSC. The experimental results have demonstrated that PLLA-PEG-PLLA triblock copolymer with a number-average molar mass of 28,230 g,·,mol,1 and an L -lactide conversion of 92.4% could be synthesized after the L -lactide/PEG2000 reaction mixture was irradiated for 3 min at 100,°C. The L -lactide/PEG feed ratio had a strong influence on the microwave-assisted ring-opening polymerization, in which higher L -lactide/PEG feed ratios led to copolymers with higher molar masses and lower L -lactide conversions. Prolonged microwave irradiation at 100,°C did not change the molar mass of the copolymers significantly. The DSC study indicated that higher glass transition and melting temperatures were obtained for PLLA-PEG-PLLA triblock copolymers with longer PLLA segment length. The synthesis of the triblock copolymers via microwave heating was much faster than via conventional heating. [source] Effect of L -arginine supplementation on immune responsiveness in patients with sickle cell disease,PEDIATRIC BLOOD & CANCER, Issue 2 2010Arnette Scavella MD Abstract Background L -arginine (L -Arg) is deficient in sickle cell disease (SSD) during vasoocclusion. We investigated possible causal relationship between L -Arg deficiency and immune dysfunction in SSD in steady-state. Procedure Fifteen patients with SSD in steady-state and 13 controls were studied. Plasma L -Arg levels were measured using liquid chromatography. T cell subsets and CD3zeta (CD3,) chain expression were analyzed using flow cytometry. Lymphocyte proliferative response to phytohemagglutinin (PHA) and production of IL-6 and interferon-gamma (IFN-,) were evaluated with and without L -Arg. Results SSD patients had significantly lower L -Arg levels than controls. CD3 and CD19 cell populations were comparable for both groups, but SSD patients had above normal numbers of natural killer cells (P,=,0.06). Patients and controls exhibited significantly increased lymphocyte blastogenesis to PHA after introduction of L -Arg to cultures; response of patients was significantly greater than values for control individuals. Proliferative response to candida in SSD patients was significantly lower than in controls; L -Arg supplementation did not increase this response. L -Arg had no effect on blastogenic response to PPD and candida albicans. No effect was likewise seen in production of IL-6 and IFN-, after addition of L -Arg. CD3, chain expression increased after addition of L -Arg in both groups; differences were insignificant. Conclusion L -Arg levels in steady-state SSD are significantly lower than in controls. L -Arg supplementation enhanced lymphocyte blastogenesis to PHA for both controls and patients, but not in response to antigen. There were no significant differences in CD3, chain expression although upregulation of expression occurred after L -Arg supplementation for both groups. Pediatr Blood Cancer. 2010;55:318,323. © 2010 Wiley,Liss, Inc. [source] Cage colour and post-harvest K+ concentration affect skin colour of Australian snapper Pagrus auratus (Bloch & Schneider, 1801)AQUACULTURE RESEARCH, Issue 9 2008Ben J Doolan Abstract In an attempt to improve post-harvest skin colour in cultured Australian snapper Pagrus auratus, a two-factor experiment was carried out to investigate the effects of a short-term change in cage colour before harvest, followed by immersion in K+ -enriched solutions of different concentrations. Snapper supplemented with 39 mg unesterified astaxanthin kg,1 for 50 days were transferred to black (for 1 day) or white cages (for 1 or 7 days) before euthanasia by immersing fish in seawater ice slurries supplemented with 0, 150, 300, 450 or 600 mmol L,1 K+ for 1 h. Each treatment was replicated with five snapper (mean weight=838 g) held individually within 0.2 m3 cages. L*, a* and b* skin colour values of all fish were measured after removal from K+ solutions at 0, 3, 6, 12, 24 and 48 h. After immersion in K+ solutions, fish were stored on ice. Both cage colour and K+ concentration significantly affected post-harvest skin colour (P<0.05), and there was no interaction between these factors at any of the measurement times (P>0.05). Conditioning dark-coloured snapper in white surroundings for 1 day was sufficient to significantly improve skin lightness (L*) after death. Although there was no difference between skin lightness values for fish held for either 1 or 7 days in white cages at measurement times up to 12 h, fish held in white cages for 7 days had significantly higher L* values (i.e. they were lighter) after 24 and 48 h of storage on ice than those held only in white cages for 1 day. K+ treatment also affected (improved) skin lightness post harvest although not until 24 and 48 h after removal of fish from solutions. Before this time, K+ treatment had no effect on skin lightness. Snapper killed by seawater ice slurry darkened (lower L*) markedly during the first 3 h of storage in contrast with all K+ treatments that prevented darkening. After 24 and 48 h of storage on ice, fish exposed to 450 and 600 mmol L,1 K+ were significantly lighter than fish from seawater ice slurries. In addition, skin redness (a*) and yellowness (b*) were strongly dependent on K+ concentration. The initial decline in response to K+ was overcome by a return of a* and b* values with time, most likely instigated by a redispersal of erythrosomes in skin erythrophores. Fish killed with 0 mmol L,1 K+ maintained the highest a* and b* values after death, but were associated with darker (lower L*) skin colouration. It is concluded that a combination of conditioning snapper in white surroundings for 1 day before harvest, followed by immersion in seawater ice slurries supplemented with 300,450 mmol L,1 K+ improves skin pigmentation after >24 h of storage on ice. [source] | ||||||||||