Elucidation of the relationship between cooking temperature, water distribution and sensory attributes of pork - a combined NMR and sensory study

Low-field NMR T(2) relaxation was measured continuously during cooking of pork samples (m. longissimus dorsi) to a final temperature of 75 °C. Simultaneously the remaining muscle was cooked in an oven to a core temperature of either 62 or 75 °C and subsequently evaluated by a sensory panel. Highly significant effects of final cooking temperature on the sensory attributes juiciness (initial and final), hardness, tenderness, crumbliness and chewing time were found. Juiciness and tenderness decreased with increasing temperature, while hardness, crumbliness and chewing time increased with increasing temperature. Distributed T(2) relaxation data revealed marked effects of temperature (62 vs. 75 °C) on the water distribution within the meat. Partial least squares (PLS) regressions were used to examine a potential prediction of sensory attributes from the distributed T(2) relaxation data, and high correlations were obtained. Moreover, loadings from the PLS regressions were analysed to evaluate the alterations in the water distribution as a function of temperature that contribute to changes in juiciness. This analysis revealed that the reduction in juiciness at 75 °C can be ascribed to changes in the size of the pores confining the myofibrillar water together with an expulsion of water.     

Aging-induced changes in microstructure and water distribution in fresh and cooked pork in relation to water-holding capacity and cooking loss - A combined confocal laser scanning microscopy (CLSM) and low-field nuclear magnetic resonance relaxation study

Confocal laser scanning microscopy (CLSM) and low-field nuclear magnetic resonance (LF-NMR) relaxometry were combined to characterize microstructural changes and water distribution in fresh and cooked pork during an aging period of 14 days. At day 1 (24 h postmortem) a few muscle fibres, which appear swollen, were observed in both fresh and cooked meat. An identical microstructure was still apparent after 14 days, however, the number of muscle fibres showing distinguished characteristics was found to increase throughout the aging period. Hence, it was apparent that during aging the individual fibres swell and disintegrate at different rates. Development in water-holding capacity (WHC) was followed during the aging period using gravimetric methods, and an increase in the WHC in the fresh meat was observed, which resembled the amount of extramyofibrillar water measured by NMR relaxometry (T₂₂ population). This was consistent with the CLSM images, as a substantial increase in the number of myofibrils that appeared swollen, capable of holding more water, was observed during aging. In the cooked meat the width of the T_21c population, reflecting the myofibrillar water in the cooked meat, was seen to decrease during the entire storage period, which corresponds to the development of a more homogeneous structure. In the CLSM data a continuous degradation during the storage period was observed, which could resemble a shift to a more homogeneous structure. Comparison of CLSM of transverse sections of fresh and cooked pork revealed a pronounced shrinkage of muscle fibres upon cooking. This resulted in large gaps between the cooked muscle fibres, which also was visible as shrinkage at the level of the individual myofibrils. This pattern was also reflected in the NMR relaxation data. The cooking-induced shrinkage of the myofibrils occurred concomitantly with a decrease in the amount of intermyofibrillar water within the individual fibre and an increase in the larger extramyofibrillar spaces between fibres, i.e. water is expelled from the myofibrillar matrix upon cooking. Accordingly, the present study demonstrated that the use of CLSM together with NMR relaxometry can provide further information on the relationship between structural characteristics of meat and resultant water distribution.     

Studies on curcumin and curcuminoids VII. Chromatographic separation and quantitative analysis of curcumin and related compounds

Summary Chromatographic analysis of curcumin and structurally related compounds is described. The poor reproducibility of the quantitative analyses is due to the interaction between the 1,3-dicarbonyl group of the molecules and the solid chromatographic support. By careful selection of the chromatographic conditions a succesful quantitative analysis could be achieved.

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Studien über Curcumin und Curcuminoide. VII. Chromatographische Trennung und quantitative Analyse von Curcumin und verwandten Verbindungen

Zusammenfassung Die chromatographische Trennung von Curcumin und verwandte Verbindungen wird beschrieben. Die schlechte Reproduzierbarkeit der quantitativen Analyse ist durch eine Interaktion zwischen der 1,3-Dicarbonylgruppe und dem chromatographischen Trägermaterial bedingt. Durch gründliche Wahl der chromatographischen Bedingungen kann eine quantitative Analyse durchgefürt werden.

     

Optimized in-phase and opposed-phase MR imaging for accurate detection of small fat or water fractions: theoretical considerations and experimental application in emulsions

Object  

To optimize strategies and measurement parameters for quantification of small fat and water fractions (<10%) in mixtures of both components by 4-point in-phase and opposed-phase gradient-echo imaging and to compare theoretical results with in-vitro experiments using emulsions.     

Quality of carrots as affected by pre‐ and postharvest factors and processing

The aim of this review is to provide an update on factors contributing to quality of carrots, with special focus on the role of pre‐ and postharvest factors and processing. The genetic factor shows the highest impact on quality variables in carrots, causing a 7–11‐fold difference between varieties in content of terpenes, β‐carotene, magnesium, iron and phenolics as well as a 1–4‐fold difference in falcarindiol, bitter taste and sweet taste. Climate‐related factors may cause a difference of up to 20‐fold for terpenes, 82% for total sugars and 30–40% for β‐carotene, sweet taste and bitter taste. Organic farming in comparison with conventional farming has shown 70% higher levels for magnesium and 10% for iron. Low nitrogen fertilisation level may cause up to 100% increase in terpene content, minor increase in dry matter (+4 to +6%) and magnesium (+8%) and reduction in β‐carotene content (?8 to ?11%). Retail storage at room temperature causes the highest reduction in β‐carotene (?70%) and ascorbic acid (?70%). Heat processing by boiling reduces shear force (?300 to ?1000%) and crispiness (?67%) as well as content of phenolics (?150%), terpenes (?85%) and total carotenes (?20%) and increases the risk of furan accumulation. Sensory and chemical quality parameters of carrots are determined mainly by genetic and climate‐related factors and to a minor extent by cultivation method. Retail temperature and storage atmosphere as well as heating procedure in processing have the highest impact in quality reduction. © 2013 Society of Chemical Industry     

Sustainable packaging design: a holistic methodology for packaging design

This study describes a holistic methodology for sustainable packaging design. This methodology studies the combined systems of packaging and the packaged products across the whole distribution chain from manufacturer to end consumer and the life cycle from raw material extraction to the waste phase. It contains a number of indicators that are grouped into the following main categories: environmental sustainability, distribution costs, product protection, market acceptance and user friendliness. The methodology integrates a number of different analytical methods. It is intended to be used in packaging design and optimisation, for idea generation, decision support and as documentation of properties of existing packaging systems. The study describes experiences with the methodology from one case study in the Norwegian Food Industry. The experiences show that the methodology is very comprehensive, and gives a good overview of the properties of a packaging solution. It enables quantitative comparisons between different packaging solutions throughout the design process. The methodology reduces the risk of implementing sub‐optimal packaging solutions. An additional benefit of the methodology is gained by working in cross‐functional teams. One potential drawback is that the methodology can be resource and data intensive. The methodology can be used as a tool box in packaging design, i.e. it is not necessary to use all methods and quantify all indicators to gain benefit. However, all indicators and requirements should be evaluated and considered. In all cases, it should be considered to include additional indicators if important sustainability issues have not been addressed. Copyright © 2010 John Wiley & Sons, Ltd.     

Method validation for strobilurin fungicides in cereals and fruit

Strobilurins are a new class of fungicides that are active against a broad spectrum of fungi. In the present work a GC method for analysis of strobilurin fungicides was validated. The method was based on extraction with ethyl acetate/cyclohexane, clean-up by gel permeation chromatography (GPC) and determination of the content by gas chromatography (GC) with electron capture (EC-), nitrogen/phosphorous (NP-), and mass spectrometric (MS-) detection. Three strobilurins, azoxystrobin, kresoxim-methyl and trifloxystrobin were validated on three matrices, wheat, apple and grapes. The validation was based on recovery tests at three or four spiking levels, determined as double determinations and repeated three times (n = 6). The mean recoveries for the three detectors were in the range of 70-114%, and the LODs were between 0.004mg/kg and 0.014mg/kg, for all three strobilurins. The values for repeatability and reproducibility were within the limits for repeatability and reproducibility given by the Horwitz equation. Validation was not accepted for azoxystrobin in grapes on all three detectors and for azoxystrobin in apple for the MS-detector. A comparison of matrix-matched standards versus standards in solvent showed varying differences     

Improved solubility of proteins from white and red clover – inhibition of redox enzymes

New alternative protein sources are needed. Clover grasses as white clover (WC) and red clover (RC) may provide a novel protein source to achieve high-quality food protein. To prevent protein oxidation, endogenous oxidative enzymes as polyphenol oxidase (PPO) and peroxidases were inhibited with sulphite. RC showed higher PPO activity than WC. Low sulphite inhibited the PPO activity in both species, but browning still occurred in RC. Sulphite did not affect the polyphenol (PP) content in WC, rather suggesting peroxidase than PPO activity. In RC juice, the PP content increased in a dose-dependent manner with increasing sulphite. High sulphite impaired browning and increased the content of soluble rubisco in RC, mainly by increasing the content of native rubisco. In vitro digestibility of RC protein increased with increasing sulphite. In conclusion, sulphite inhibited oxidative enzymes and increased the quality of protein extracted from WC and RC.     

Isobutane/2-butene alkylation on dealuminated H EMT and H FAU

The alkylation of isobutane with 2-butene on dealuminated hexagonal H EMT and dealuminated cubic faujasite H FAU with Si/Al ratios of 5–6 was studied at 80°C and compared with results obtained for the as-synthesized and calcined parent material with Si/Al ratios of 3.5. In both cases, the dealuminated samples favour an improved profile with respect to the alkylate yield and selectivity after 3 h reaction time, with dealuminated H EMT as the superior system. The alkylate composition consisted of 76% and about 70% C₈ paraffins for dealuminated H EMT and dealuminated H FAU, respectively. Within the C₈ fractions the three trimethylpentanes (TMP) 2,3,3-, 2,3,4- and 2,2,4-TMP were the dominating product compounds in all tests, whereas a higher content of dimethylhexanes (DMH) was observed for the H FAUs, both dealuminated and parent material. However, among the four trimethylpentanes (2,2,3-, 2,2,4-, 2,3,3- and 2,3,4-TMP) usually the 2,3,3-TMP and 2,3,4-TMP were the main compounds formed, at least for the dealuminated samples. Oligomerization was suppressed by using the dealuminated samples, however, increasing amounts of C₈ olefins after about one half of the monitored reaction time was observed for the H FAUs. By contrast, the H EMTs exhibited much less formation of C₈ olefins (and on a constant level) even after 300 min reaction time. The deactivated samples showed mainly formation of paraffinic coke.     

Coping with job stress and burnout in the human services.

Conducted a mail survey of 141 human service workers (aged 25–65 yrs) to investigate the effects of coping on psychological strain and burnout produced by job stress. The survey assessed job stressors and coping strategies with open-ended questions and measured strain using closed-ended alienation, satisfaction, and symptom scales. Because previous research suggested that individual coping responses do not alleviate strain produced by job stress, the survey elicited information on group coping (social support) and on coping strategies initiated by agencies. Job stress was associated with high levels of strain, and group coping with low levels, but individual responses had little effect. Although Ss identified many strategies that agencies could use to reduce stress and strain, actual use of such strategies was slight. Because men and women worked in the same jobs, no sex differences in individual coping were predicted and none were found; women, however, reported more social support than men. There was no evidence for moderating (interaction) effects of stress and coping on strain. Results suggest that social service agencies should take actions to reduce stress among employees. (57 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)