Evaluation of E-beam irradiation and storage time in pork exudates using NMR metabolomics.

Seventy-two exudates from pork tenderloin samples, subjected to E-beam irradiation treatments, have been employed to monitor, through 1H NMR analysis, the effects of irradiation dose (0, 1, 2 and 6 kGy) and storage time (1, 6 and 12 days). As far as we know, this is the first study where meat exudate is employed to monitor the effects of irradiation dose and storage time. The 1H NMR spectra, obtained after ~ 2 min, allowed to determine the main components of the pork exudate. Results show that 1H NMR-based metabolomics provides valuable information about the metabolic changes suffered during storage and how these transformations could be affected by E-beam irradiation treatment. The ease to obtain exudates, the simple NMR sample preparation, the good correlation between the selected metabolites, the irradiation treatment and the storage times point to that this study could be the first step to develop a new method for analysis and control of meat conservation and to evaluate its irradiation treatment.

Use of MRI as a predictive tool for physicochemical and rheologycal features during cured ham manufacturing.

Magnetic resonance imaging (MRI) was used to study the structural changes during dry-cured ham manufacturing. T1, T2 and apparent diffusion coefficient (ADC) were determined. Dry cured hams were analysed at different steps of the manufacturing process (raw, salted, post salted, half-cured and cured). Structural changes were linked with the rheological behaviour, estimated by texture profile analysis (TPA) performed in three different muscles of hams (semimembranosus, semitendinosus and biceps femoris). A decrease for T1, T2 and ADC parameters during the curing process was observed, connected to the dehydration kinetics and salt diffusion. Curing process increased hardness and chewiness and reduced elasticity and cohesiveness. Mathematical models were defined to obtain useful equations to monitor ripening. Multiple and simple linear regression models were performed to predict water and salt content and rheological features evolution through MRI parameters. Best settings were achieved with water and salt content for the three studied muscles (R2 around 0.90). T1, T2 and ADC showed a negative correlation with hardness and a positive relation with springiness and cohesiveness.

Label-free magnetic resonance imaging to locate live cells in three-dimensional porous scaffolds.

Porous scaffolds are widely tested materials used for various purposes in tissue engineering. A critical feature of a porous scaffold is its ability to allow cell migration and growth on its inner surface. Up to now, there has not been a method to locate live cells deep inside a material, or in an entire structure, using real-time imaging and a non-destructive technique. Herein, we seek to demonstrate the feasibility of the magnetic resonance imaging (MRI) technique as a method to detect and locate in vitro non-labelled live cells in an entire porous material. Our results show that the use of optimized MRI parameters (4.7 T; repetition time = 3000 ms; echo time = 20 ms; resolution 39 × 39 µm) makes it possible to obtain images of the scaffold structure and to locate live non-labelled cells in the entire material, with a signal intensity higher than that obtained in the culture medium. In the current study, cells are visualized and located in different kinds of porous scaffolds. Moreover, further development of this MRI method might be useful in several three-dimensional biomaterial tests such as cell distribution studies, routine qualitative testing methods and in situ monitoring of cells inside scaffolds.

In vivo virtual histology of mouse embryogenesis by ultrasound biomicroscopy and magnetic resonance imaging.

Feasibility of magnetic resonance imaging (MRI) and ultrasound biomicroscopy (UBM) for sequential in vivo study of mouse embryo development between Days 6.5 and 13.5 of pregnancy was assessed in a first experiment. A second trial, based on the results of the first, determined the accuracy of UBM for imaging morphogenesis from implantation to the late embryo stage (Days 4.5 to 15.5). MRI allowed imaging of the entire uterus and all gestational sacs and embryos inside whilst the small scanning range of UBM precluded accurate counting of fetuses; however, its high resolution identified the decidual reaction at implantation sites from Day 4.5. At later stages, it was possible to assess key morphogenetic processes such as differentiation of the placenta, the cephalic region, the thoracic and abdominal organs, the skeletal system and the limbs, and dynamic structures such as the cardiovascular system. Thus, both techniques are reliable for in utero imaging of mouse embryo development. MRI may be more appropriate for studying embryo lethality and intrauterine growth retardation, because the entire uterus can be viewed. UBM may be more suitable for studies of cellular components of organs and tissues and assessment of haemodynamic changes in the circulatory system.

Osteoporosis increases the severity of cartilage damage in an experimental model of osteoarthritis in rabbits.

OBJECTIVE: To evaluate the effect of osteoporosis (OP) in cartilage damage developed in an experimental model of osteoarthritis (OA) in mature female rabbits in order to investigate the relationship between OP and OA. METHODS: OA was experimentally induced by anterior cruciate section and partial medial meniscectomy in the left knee of 12 rabbits. OP was experimentally induced prior to OA in six rabbits by bilateral ovariectomy (OVX) and systemic corticosteroid administration during 4 weeks. Knees were evaluated with high resolution magnetic resonance imaging (MRI) before knee surgery to rule out any detrimental effect of corticosteroids on cartilage. Gross and microscopic cartilage changes were assessed 16 weeks after surgery in bilateral knees. Left knees were considered osteoarthritic or osteoarthritic plus osteoporotic. Right knees were used as osteoporotic and healthy controls, respectively. Bone mineral density (BMD) was measured with dual energy X-ray absorptiometry (DXA) at the lumbar spine, global knee and subchondral knee bone, and its variations correlated with cartilage abnormalities. RESULTS: MRI before knee surgery disclosed no cartilage or bone abnormalities in any of the studied groups. OP increased the severity of cartilage abnormalities in experimental knee OA significantly (P<0.05). Cartilage damage was inversely correlated with BMD variations measured at the lumbar spine (r=-0.74; P=0.015). BMD changes in global and subchondral knee bone also showed a trend to correlate inversely with cartilage damage. CONCLUSIONS: Prior induction of OP increases the severity of cartilage damage in experimental OA. Increase in cartilage damage correlates with bone loss. These findings suggest a direct relationship between OP and OA.

Application of MRI to monitor the process of ripening and decay in citrus treated with chitosan solutions.

Chitosan is a biopolymer, which has numerous applications in agriculture and agroindustries. Coating fruit and vegetables with chitosan has some positive advantages for the long-term storage of foods, because the film of chitosan provides a kind of an active package, which allows a gradual release of preservatives, thus inhibiting fungal growth and maintaining the external appearance of the fruit for a longer time In this study, two varieties of citrus, Fortune mandarins and Valencia oranges were coated with Biorend(R) (IDEBIO S.L., Salamanca, Spain) (a compound whose active molecule is chitosan), to investigate its effect on maturity, decay, and damage, and therefore, to find a better method for the long term storage of fruit. The effect of chitosan as a fungistatic was also studied. To that end, the fruit was maintained in a damp storage room, ideal conditions for the growth of fungi. The magnetic resonance imaging (MRI) technique was used to monitor the process of ripening and decay in the citrus fruit that had been coated with chitosan. The dissolution of the chitosan on the mandarins and oranges produced excellent results in terms of percentage of weight loss, MRI, and visual appearance.

Mealiness assessment in apples and peaches using MRI techniques.

Mealiness (woolliness in peaches) is a negative attribute of sensory texture that combines the sensation of a desegregated tissue with the sensation of lack of juiciness. In this study, 24 apples cv. Top Red and 8 peaches cv. Maycrest, submitted to 3 and 2 different storage conditions respectively have been tested by mechanical and MRI techniques to assess mealiness. With this study, the results obtained on apples in a previous work have been validated using mathematical features from the histograms of the T2 maps: more skewed and the presence of a tail in mealy apples, similar to internal breakdown. In peaches, MRI techniques can also be used to identify woolly fruits. Not all the changes found in the histograms of woolly peaches are similar from those observed in mealy apples pointing to a different underlying physiological change in both disorders.

Mealiness assessment in apples using MRI techniques.

Small samples of Top Red apples stored 6 months under controlled atmosphere (expected to be non-mealy) and 2 degrees C (expected to be mealy) have been used for MRI imaging. Multi-slice-multi-echo magnetic resonance images (64*64 pixels) have been recorded with a 8 ms echo time. Three out of four apples corresponding to the sample maintained under controlled atmosphere did not developed mealiness while three out of four fruits corresponding to the sample stored at 2 degrees C became mealy after 6 months of storage. The minimum T2 values obtained for the mealy apples show to be significantly lower (F = 13.21) when compared with non-mealy apples pointing that a more desegregated structure and a lower juiciness content leads to lower T2 signal. Also, there is a significant linear correlation (r = -0.76) between the number of pixels with a T2 value below 35 ms within a fruit image and the deformation parameter registered during the Magness-Taylor firmness test. Finally, all T2 maps of mealy apples show a regional variation of contrast which is not shown for non-mealy apples. Significant differences (F = 19.43) between mealy and non-mealy apples are found in the histograms of the T2 maps as mealy apples show a skew histogram combined with a "tail" in their high T2 extreme which is not shown in the histograms of non-mealy apples. These histogram features are also shown for an apple showing internal breakdown indicating that in mealy apples there is a differential water movement that may precede internal breakdown.