Determination of Optimum Concentrations of a Food Ingredient Using Survival Analysis Statistics

ABSTRACT:  For desirable attributes in food products such as red color in a strawberry yogurt, the color can be too light, okay, or too dark, leading to 2 events of interest: the transition of too light to ok, and the transition of ok to too dark. The objective of the present work was to develop a model using survival analysis statistics to allow modeling these 2 events and thus allow prediction of the optimum color based on acceptance or rejection data obtained from consumers. Concepts and calculations were applied to a data set obtained from 60 consumers who each looked at 7 yogurt samples with different red color intensities, answering whether they found the samples too light, okay, or too dark. From this censored data set parametric models were obtained which allowed optimum color estimation and segmentation of consumers in groups according to whether they liked lighter or darker colored yogurts. Applications of the model to other food ingredients and to the ripening and spoilage of fruit are discussed.     

Use of Electrospinning to Develop Antimicrobial Biodegradable Multilayer Systems: Encapsulation of Cinnamaldehyde and Their Physicochemical Characterization

In this work, three active bio-based multilayer structures, using a polyhydroxybutyrate-co-valerate film with a valerate content of 8 % (PHBV8) as support, were developed. To this end, a zein interlayer with or without cinnamaldehyde (CNMA) was directly electrospun onto one side of the PHBV8 film and the following systems were developed: (1) without an outer layer; (2) using a PHBV8 film as outer layer; and (3) using an alginate-based film as outer layer. These multilayer structures were characterized in terms of water vapour and oxygen permeabilities, transparency, intermolecular arrangement and thermal properties. The antimicrobial activity of the active bio-based multilayer systems and the release of CNMA in a food simulant were also evaluated. Results showed that the presence of different outer layers reduced the transport properties and transparency of the multilayer films. The active bio-based multilayer systems showed antibacterial activity against Listeria monocytogenes being the multilayer structure prepared with CNMA and PHBV outer layers (PHBV + zein/CNMA + PHBV) the one that showed the greater antibacterial activity. The release of CNMA depended on the multilayer structures, where both Fick’s and Case II transport—polymer relaxation explained the release of CNMA from the multilayer systems.Overall, the deposition of electrospun CNMA-loaded zein fibres on a PHBV8 layer is a promising methodology for the development of active bio-based multilayer systems, with a great potential for food packaging applications.     

HRMAS-NMR spectroscopy and multivariate analysis meat characterisation

(1)H-high resolution magic angle spinning-nuclear magnetic resonance spectroscopy was employed to gain the metabolic profile of longissimus dorsi and semitendinosus muscles of four different breeds: Chianina, Holstein Friesian, Maremmana and Buffalo. Principal component analysis, partial least squares projection to latent structure - discriminant analysis and orthogonal partial least squares projection to latent structure - discriminant analysis were used to build models capable of discriminating the muscle type according to the breed. Data analysis led to an excellent classification for Buffalo and Chianina, while for Holstein Friesian the separation was lower. In the case of Maremmana the use of intelligent bucketing was necessary due to some resonances shifting allowed improvement of the discrimination ability. Finally, by using the Variable Importance in Projection values the metabolites relevant for the classification were identified.     

Reference-free PRFS MR-thermometry using near-harmonic 2-D reconstruction of the background phase

Proton resonance frequency shift (PRFS) MR thermometry (MRT) is the generally preferred method for monitoring thermal ablation, typically implemented with gradient-echo (GRE) sequences. Standard PRFS MRT is based on the subtraction of a temporal reference phase map and is, therefore, intrinsically sensitive to tissue motion (including deformation) and to external perturbation of the magnetic field. Reference-free (or reference-less) PRFS MRT has been previously described by Rieke and was based on a 2-D polynomial fit performed on phase data from outside the heated region, to estimate the background phase inside the region of interest. While their approach was undeniably a fundamental progress in terms of robustness against tissue motion and magnetic perturbations, the underlying mathematical formalism requires a thick unheated border and may be subject to numerical instabilities with high order polynomials. A novel method of reference-free PRFS MRT is described here, using a physically consistent formalism, which exploits mathematical properties of the magnetic field in a homogeneous or near-homogeneous medium. The present implementation requires as input the MR GRE phase values along a thin, nearly-closed and unheated border. This is a 2-D restriction of a classic Dirichlet problem, working on a slice per slice basis. The method has been validated experimentally by comparison with the “ground truth” data, considered to be the standard PRFS method for static ex vivo tissue. “Zero measurement” of the gradient-echo phase baseline was performed in healthy volunteer liver with rapid acquisition (300 ms/image). In vivo data acquired in sheep liver during MR-guided high intensity focused ultrasound (MRgHIFU) sonication were post-processed as proof of applicability in a therapeutic scenario. Bland and Altman mean absolute difference between the novel method and the “ground truth” thermometry in ex vivo static tissue ranged between 0.069 °C and 0.968 °C, compared to the inherent “white” noise SD of 0.23 °C. The accuracy and precision of the novel method in volunteer liver were found to be on average 0.13 °C and respectively 0.65 °C while the inherent “white” noise SD was on average 0.51 °C. The method was successfully applied to large ROIs, up to 6.2 cm inner diameter, and the computing time per slice was systematically less than 100 ms using C++. The current limitations of reference-free PRFS thermometry originate mainly from the need to provide a nearly-closed border, where the MR phase is artifact-free and the tissue is unheated, plus the potential need to reposition that border during breathing to track the motion of the anatomic zone being monitored.A reference-free PRFS thermometry method based on the theoretical framework of harmonic functions is described and evaluated here. The computing time is compatible with online monitoring during local thermotherapy. The current reference-free MRT approach expands the workflow flexibility, eliminates the need for respiratory triggers, enables higher temporal resolution, and is insensitive to unique-event motion of tissue.     

Kth-Aggressor Fault (KAF)-based Thru-Silicon-Via Interconnect Built-In Self-Test and Diagnosis

Three-dimensional (3D) integration is a key technology for systems whose performance and power requirements cannot be achieved by traditional silicon technologies. 3D chips consist of two or more stacked silicon dies connected by short inter-die wires called Thru-Silicon-Vias (TSVs). Despite its potential, the poor reliability and yield, thermal management and testing issues remain major challenges of 3D integration. We address the TSV interconnect test challenge of 3D chips by using Interconnect Built-In Self-Test (IBIST) techniques. The proposed test strategy must sensitize structural faults like opens and shorts, and delay faults due to crosstalk. A possible approach is the well-known Maximum Aggressor Fault (MAF) model. Unfortunately, this model is too conservative and it leads to long test sequences and non-negligible hardware costs. Therefore, we present an alternative solution: the K^th-Aggressor Fault (KAF) model. In our model, aggressors of victim wires are neighboring wires within an optimized distance order K. The aggressor order K is technology-dependent and is determined such that the test times are minimal and the fault coverage is maximal. KAF-based IBIST implementation targeting TSV tests occupies three times less area than similar MAF-/marching-based implementations. We also propose a reconfigurable KAF-based IBIST implementation where tests can be performed using different aggressor orders K. Although the reconfigurable IBIST area is significant, interconnect tests during system lifetime can be performed using lower aggressor orders, reducing test duration and improving TSV availability.     

CSL: Configurable Fault Tolerant Serial Links for Inter-die Communication in 3D Systems

Three dimensional (3D) integrated systems become a reality nowadays, as Thru-Silicon-Via (TSV) technologies mature. 3D integration promises significant performance and energy efficiency improvements by reducing the signal travel distances and integrating more capabilities on a single chip. High integration costs, thermal management, and poor reliability and yield are major challenges of TSV based 3D chips. High structural and parametric fault rates due to manufacturing defects makes it difficult to achieve high interconnect yield using only spare-based repair solutions. In this paper we address the TSV yield issue by implementing the inter-die links of 3D chips as Configurable fault-tolerant Serial Links (CSLs). When there are not enough available functional TSVs, faults are tolerated by performing data serialization. CSLs help reduce chip costs by improving the TSV yield with very few or no spares at all. For 3D Networks-on-Chip (3D NoCs) we show that the CSL yield improvement comes with moderate area overheads (~12–26%) and small performance penalties (less than 5% average latency overhead).     

Structure and oxidative stability of oil in water emulsions as affected by rutin and homogenization procedure

The structural properties of oil-in-water (O/W) emulsions, as well as their oxidative stability upon storage at 50 °C, were studied. Eight different formulations were prepared, with the aim of studying the effect of three variables: the composition of the oil phase, the presence of the flavonoid rutin and the homogenization procedure on the structure and the oxidative stability. It was found that high pressure homogenization, through droplet size reduction, stabilized the emulsions both against creaming and oil oxidation. The interfacial protein was also partially replaced by rutin, further improving the stability of the emulsions, whereas purification of the oil phase had hardly any effect. Thus, the structural and oxidative stability of emulsions was controlled by the size of the droplets and improved by the addition of rutin.     

Antihypertensive and antithrombotic activities of a commercial fermented milk product made with Lactobacillus casei Shirota and Streptococcus thermophilus

Peptides which inhibit the human angiotensin‐converting enzyme (ACE) may be released during milk fermentation, and the micro‐organisms or fermentation conditions influence the specific peptides produced. The aim of this study was to evaluate the ACE inhibitory and antithrombotic activities of a fermented milk product commercially available in Mexico. Viable cell numbers, protein hydrolysis and the pH remained constant during refrigerated storage. The IC₅₀ of ACE inhibitory activity was 31.38 mg/mL. Eight peptide fractions exhibited ACE inhibitory activity and six showed antithrombotic activity. Two fractions showed both. This is the first time that both activities have been reported in a commercial probiotic product.     

The Sedentary Lifestyle and Masticatory Dysfunction: Time to Review the Contribution to Age-Associated Cognitive Decline and Astrocyte Morphotypes in the Dentate Gyrus

As aging and cognitive decline progresses, the impact of a sedentary lifestyle on the appearance of environment-dependent cellular morphologies in the brain becomes more apparent. Sedentary living is also associated with poor oral health, which is known to correlate with the rate of cognitive decline. Here, we will review the evidence for the interplay between mastication and environmental enrichment and assess the impact of each on the structure of the brain. In previous studies, we explored the relationship between behavior and the morphological features of dentate gyrus glial fibrillary acidic protein (GFAP)-positive astrocytes during aging in contrasting environments and in the context of induced masticatory dysfunction. Hierarchical cluster and discriminant analysis of GFAP-positive astrocytes from the dentate gyrus molecular layer revealed that the proportion of AST1 (astrocyte arbors with greater complexity phenotype) and AST2 (lower complexity) are differentially affected by environment, aging and masticatory dysfunction, but the relationship is not straightforward. Here we re-evaluated our previous reconstructions by comparing dorsal and ventral astrocyte morphologies in the dentate gyrus, and we found that morphological complexity was the variable that contributed most to cluster formation across the experimental groups. In general, reducing masticatory activity increases astrocyte morphological complexity, and the effect is most marked in the ventral dentate gyrus, whereas the effect of environment was more marked in the dorsal dentate gyrus. All morphotypes retained their basic structural organization in intact tissue, suggesting that they are subtypes with a non-proliferative astrocyte profile. In summary, the increased complexity of astrocytes in situations where neuronal loss and behavioral deficits are present is counterintuitive, but highlights the need to better understand the role of the astrocyte in these conditions.