Twenty-three years of PCR-based seafood authentication assay development: What have we learned?

Seafood is a prime target for fraudulent activities due to the complexity of its supply chain, high demand, and difficult discrimination among species once morphological characteristics are removed. Instances of seafood fraud are expected to increase due to growing demand. This manuscript reviews the application of DNA-based methods for commercial fish authentication and identification from 2000 to 2023. It explores (1) the most common types of commercial fish used in assay development, (2) the type of method used, (3) the gene region most often targeted, (4) provides a case study of currently published assays or primer-probe pairs used for DNA amplification, for specificity, and (5) makes recommendations for ensuring standardized assay-based reporting for future studies. A total of 313 original assays for the detection and authentication of commercial fish species from 191 primary articles published over the last 23 years were examined. The most explored DNA-based method was real-time polymerase chain reaction (qPCR), followed by DNA sequencing. The most targeted gene regions were cytb (cytochrome b) and COI (cytochrome c oxidase 1). Tuna was the most targeted commercial fish species. A case study of published tuna assays (n = 19) targeting the cytb region found that most assays were not species-specific through in silico testing. This was conducted by examining the primer mismatch for each assay using multiple sequence alignment. Therefore, there is need for more standardized DNA-based assay reporting in the literature to ensure specificity, reproducibility, and reliability of results. Factors, such as cost, sensitivity, quality of the DNA, and species, should be considered when designing assays.

Molecular motifs encoding self-assembly of peptide fibers into molecular gels.

Peptides are a promising class of gelators, due to their structural simplicity, biocompatibility and versatility. Peptides were synthesized based on four amino acids: leucine, phenylalanine, tyrosine and tryptophan. These peptide gelators, with systematic structural variances in side chain structure and chain length, were investigated using Hansen solubility parameters to clarify molecular features that promote gelation in a wide array of solvents. It is of utmost importance to combine both changes to structural motifs and solvent in simultaneous studies to obtain a global perspective of molecular gelation. It was found that cyclization of symmetric dipeptides, into 2,5-diketopiperazines, drastically altered the gelation ability of the dipeptides. C-l-LL and C-l-YY, which are among the smallest peptide LMOGs reported to date, are robust gelators with a large radius of gelation (13.44 MPa1/2 and 13.90 MPa1/2, respectively), and even outperformed l-FF (5.61 MPa1/2). Interestingly, both linear dipeptides (l-FF and l-LL) gelled similar solvents, yet when cyclized only cyclo-dityrosine was a robust gelator, while cyclo-diphenylalanine was not. Changes in the side chains drastically affected the crystal morphology of the resultant gels. Symmetric cyclo dipeptides of leucine and tyrosine were capable of forming extremely high aspect ratio fibers in numerous solvents, which represent new molecular motifs capable of driving self-assembly.

Potential applications of luminescent molecular rotors in food science and engineering.

Fluorescent molecular rotors (MRs) are compounds whose emission is modulated by segmental mobility; photoexcitation generates a locally excited (LE), planar state that can relax either by radiative decay (emission of a photon) or by formation of a twisted intramolecular charge transfer (TICT) state that can relax nonradiatively due to internal rotation. If the local environment around the probe allows for rapid internal rotation in the excited state, fast non-radiative decay can either effectively quench the fluorescence or generate a second, red-shifted emission band. Conversely, any environmental restriction to twisting in the excited state due to free volume, crowding or viscosity, slows rotational relaxation and promotes fluorescence emission from the LE state. The environmental sensitivity of MRs has been exploited extensively in biological applications to sense microviscosity in biofluids, the stability and physical state of biomembranes, and conformational changes in macromolecules. The application of MRs in food research, however, has been only marginally explored. In this review, we summarize the main characteristics of fluorescent MRs, their current applications in biological research and their current and potential applications as sensors of physical properties in food science and engineering.

Molecular Nuances Governing the Self-Assembly of 1,3:2,4-Dibenzylidene-d-sorbitol.

1,3:2,4-Dibenzylidene-d-sorbitol (DBS) is the gold-standard for low-molecular-weight organogelators (LMOGs). DBS gels a wide array of solvents, as illustrated by the large Hansen sphere representing gels (2δd = 33.5 MPa1/2, δp = 7.5 MPa1/2, and δh = 8.7 MPa1/2; radius = 11.2 MPa1/2). Derivatives of DBS have been synthesized to isolate and determine molecular features essential for organogelation. In this work, π-π stacking and hydrogen bonding are the major noncovalent interactions examined. The importance of π-π stacking was studied using 1,3:2,4 dicyclohexanecarboxylidene-d-sorbitol (DCHS), which eliminates possible π-π stacking while still conserving the other structural aspects of DBS. The replacement of the benzyl groups with cyclohexyl groups led to a very a poor gelator; only one of the several solvents examined, carbon tetrachloride, formed a gel. 1,3:2,4-Diethylidene-d-sorbitol (DES), another DBS analogue incapable of π-π stacking but with very different polarity, gelated a large Hansen space (2δd = 34.0 MPa1/2, δp = 10.9 MPa1/2, and δh = 10.8 MPa1/2; radius = 9.2 MPa1/2). DES gels solvents with higher δp and δh values than DBS. To assess the role of hydrogen bonding, DBS was acetalated (A-DBS), and it was found that the Hansen space gelated by A-DBS shifted to less polar solvents with higher hydrogen-bonding Hansen solubility parameters (HSPs) (2δd = 33.8 MPa1/2, δp = 6.3 MPa1/2, and δh = 9.6 MPa1/2; radius = 11.1 MPa1/2) than for DBS. These systematic structural modifications are the first step in exploring how specific intermolecular features alter aspects of Hansen space corresponding to positive gelation outcomes.

Tryptophan Fluorescence Yields and Lifetimes as a Probe of Conformational Changes in Human Glucokinase.

Five variants of glucokinase (ATP-D-hexose-6-phosphotransferase, EC 2.7.1.1) including wild type and single Trp mutants with the Trp residue at positions 65, 99, 167 and 257 were prepared. The fluorescence of Trp in all locations studied showed intensity changes when glucose bound, indicating that conformational change occurs globally over the entire protein. While the fluorescence quantum yield changes upon glucose binding, the enzyme's absorption spectra, emission spectra and fluorescence lifetimes change very little. These results are consistent with the existence of a dark complex for excited state Trp. Addition of glycerol, L-glucose, sucrose, or trehalose increases the binding affinity of glucose to the enzyme and increases fluorescence intensity. The effect of these osmolytes is thought to shift the protein conformation to a condensed, high affinity form. Based upon these results, we consider the nature of quenching of the Trp excited state. Amide groups are known to quench indole fluorescence and amides of the polypeptide chain make interact with excited state Trp in the relatively unstructured, glucose-free enzyme. Also, removal of water around the aromatic ring by addition of glucose substrate or osmolyte may reduce the quenching.

Comparing and correlating solubility parameters governing the self-assembly of molecular gels using 1,3:2,4-dibenzylidene sorbitol as the gelator.

Solvent properties play a central role in mediating the aggregation and self-assembly of molecular gelators and their growth into fibers. Numerous attempts have been made to correlate the solubility parameters of solvents and gelation abilities of molecular gelators, but a comprehensive comparison of the most important parameters has yet to appear. Here, the degree to which partition coefficients (log P), Henry's law constants (HLC), dipole moments, static relative permittivities (ε(r)), solvatochromic E(T)(30) parameters, Kamlet-Taft parameters (ß, α, and π), Catalan's solvatochromic parameters (SPP, SB, and SA), Hildebrand solubility parameters (δ(i)), and Hansen solubility parameters (δ(p), δ(d), δ(h)) and the associated Hansen distance (R(ij)) of 62 solvents (covering a wide range of properties) can be correlated with the self-assembly and gelation of 1,3:2,4-dibenzylidene sorbitol (DBS) gelation, a classic molecular gelator, is assessed systematically. The approach presented describes the basis for each of the parameters and how it can be applied. As such, it is an instructional blueprint for how to assess the appropriate type of solvent parameter for use with other molecular gelators as well as with molecules forming other types of self-assembled materials. The results also reveal several important insights into the factors favoring the gelation of solvents by DBS. The ability of a solvent to accept or donate a hydrogen bond is much more important than solvent polarity in determining whether mixtures with DBS become solutions, clear gels, or opaque gels. Thermodynamically derived parameters could not be correlated to the physical properties of the molecular gels unless they were dissected into their individual HSPs. The DBS solvent phases tend to cluster in regions of Hansen space and are highly influenced by the hydrogen-bonding HSP, δ(h). It is also found that the fate of this molecular gelator, unlike that of polymers, is influenced not only by the magnitude of the distance between the HSPs for DBS and the HSPs of the solvent, R(ij), but also by the directionality of R(ij): if the solvent has a larger hydrogen-bonding HSP (indicating stronger H-bonding) than that of the DBS, then clear gels are formed; opaque gels form when the solvent has a lower δ(h) than does DBS.

Virtualization and digital twins of the food supply chain for enhanced food safety.

Meeting food safety requirements without jeopardizing quality attributes or sustainability involves adopting a holistic perspective of food products, their manufacturing processes and their storage and distribution practices. The virtualization of the food supply chain offers opportunities to evaluate, simulate, and predict challenges and mishaps potentially contributing to present and future food safety risks. Food systems virtualization poses several requirements: (1) a comprehensive framework composed of instrumental, digital, and computational methods to evaluate internal and external factors that impact food safety; (2) nondestructive and real-time sensing methods, such as spectroscopic-based techniques, to facilitate mapping and tracking food safety and quality indicators; (3) a dynamic platform supported by the Internet of Things (IoT) interconnectivity to integrate information, perform online data analysis and exchange information on product history, outbreaks, exposure to risky situations, etc.; and (4) comprehensive and complementary mathematical modeling techniques (including but not limited to chemical reactions and microbial inactivation and growth kinetics) based on extensive data sets to make realistic simulations and predictions possible. Despite current limitations in data integration and technical skills for virtualization to reach its full potential, its increasing adoption as an interactive and dynamic tool for food systems evaluation can improve resource utilization and rational design of products, processes and logistics for enhanced food safety. Virtualization offers affordable and reliable options to assist stakeholders in decision-making and personnel training. This chapter focuses on definitions and requirements for developing and applying virtual food systems, including digital twins, and their role and future trends in enhancing food safety.

Extraction, Identification, and Quantification of Polyphenols from the Theobroma cacao L. Fruit: Yield vs. Environmental Friendliness.

The cacao fruit is a rich source of polyphenols, including flavonoids and phenolic acids, which possess significant health benefits. The accurate identification and quantification of these bioactive compounds extracted from different parts of the cacao fruit, such as pods, beans, nibs, and cacao shells, require specific treatment conditions and analytical techniques. This review presents a comprehensive comparison of extraction processes and analytical techniques used to identify and quantify polyphenols from various parts of the cacao fruit. Additionally, it highlights the environmental impact of these methods, exploring the challenges and opportunities in selecting and utilizing extraction, analytical, and impact assessment techniques, while considering polyphenols' yield. The review aims to provide a thorough overview of the current knowledge that can guide future decisions for those seeking to obtain polyphenols from different parts of the cacao fruit.

Morphological changes and color development during cookie baking-Kinetic, heat, and mass transfer considerations.

Color and shape are important quality attributes in baked goods, particularly cookies. Composition and processing conditions determine and influence color development and morphological changes in these baked goods. The objective of this study was to systematically evaluate the evolution of color and shape during baking to determine useful correlations that can be implemented during the assessment and modeling of the baking process. Cookies (AACC-I standard protocol 10-53.01) were baked at 185, 205, and 225°C. Moisture content, water activity, surface temperature, characteristic dimensions (radius and thickness), and color indexes (lightness, redness, blueness, and browning index [BI]) were monitored at different locations on the cookie surface and baking times. Relationships among the tested conditions were explored using correlation analysis. The cookies' dimensions and color indexes were strongly correlated with changes in moisture content over time, and those relationships were characterized using empirical models. The temperature dependence of the kinetic parameters of the changes in lightness and BI was also described and deemed independent of the location on the cookie surface. This study provides insights into the influence of heat and mass transfer on the physical and physicochemical changes of cookies during baking. The kinetic and secondary models developed in this study can serve as important components for establishing a comprehensive approach for coupling heat transfer, mass transfer, and reaction kinetics to estimate and optimize cookie-baking processes. PRACTICAL APPLICATION: The findings from this study provide valuable information for better understanding the morphological changes and color developments during the cookie-baking process. The quantitative data and models generated in this study will allow identifying baking conditions for better quality development.

Mapping deterioration in electrospun zein nonwoven nanostructures encapsulating corn oil.

Electrospun nonwovens of biopolymers are gaining popularity in filtration, coatings, encapsulation, and packaging materials. However, their applications are hindered by limited stability, particularly when loaded with lipids. This research aimed to apply a multiscale approach to gain insights into deteriorative processes, e.g., oxidation, limiting the shelf life of these complex materials, using corn oil-loaded electrospun zein nonwovens as a model system. Oil-doped zein electrospun nonwovens were stored in the dark at 23 °C and 33% relative humidity for 28 days and tested at selected intervals to monitor their morphology and mechanical properties. Lipid oxidation was assessed using the thiobarbituric acid reactive species (TBARS) assay. The photophysical properties of intrinsic, i.e., tyrosine (Tyr), and extrinsic, i.e., boron-dipyrromethene undecanoic acid 581/591 (BODIPY C11), lumiphores were also monitored to evaluate changes in local molecular rigidity, and oxidation, respectively. The protein secondary structure was determined with Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) analysis of the oil-loaded electrospun nonwovens revealed that the diameter of the ribbon-like fiber significantly decreased during storage from 701 ± 23 nm to 620 ± 44 nm. Breakage of the electrospun fibers was observed and correlated with increased brittleness and molecular rigidity of the nonwoven material, reflected by an increase in Tyr emission intensity and phosphorescence lifetime. Changes in tensile strength, brittleness and matrix rigidity also correlated with a zein secondary structure transition from unordered to ordered ß-sheets. Raman and luminescence micrographs showed oil migration during storage, thereby increasing lipid oxidation. The correlation between local rigidity and lipid distribution/oxidation suggests that reorganizing protein structures increased material brittleness and displaced encapsulated oils within the electrospun fiber. Understanding deteriorative mechanisms aids in developing innovative strategies to improve the stability of these novel food-grade materials.

Personalized, digitally designed 3D printed food towards the reshaping of food manufacturing and consumption.

The emerging world of 3D food printing is reviewed. Its role in food manufacturing, including benefits and impacts, underemphasized gastrophysical aspects, and limitations are discussed. Foods can be digitally designed and physically prepared using the layer-by-layer deposition of food components, unleashing opportunities to deliver nutritionally personalized food and new food-human interactions. Existing bottlenecks, under-researched gastropsychophysical aspects, and the lack of harmonized standards hindering its use for mass production are mentioned.

Bigels as Delivery Systems: Potential Uses and Applicability in Food.

Bigels have been mainly applied in the pharmaceutical sector for the controlled release of drugs or therapeutics. However, these systems, with their intricate structures, hold great promise for wider application in food products. Besides their classical role as carrier and target delivery vehicles for molecules of interest, bigels may also be valuable tools for building complex food structures. In the context of reducing or even eliminating undesirable (but often highly functional) food components, current strategies often critically affect food structure and palatability. The production of solid fat systems that are trans-fat-free and have high levels of unsaturated fatty acids is one of the challenges the food industry currently faces. According to recent studies, bigels can be successfully used as ingredients for total or partial solid fat replacement in complex food matrices. This review aims to critically assess current research on bigels in food and pharmaceutical applications, discuss the role of bigel composition and production parameters on the characteristics of bigels and further expand the use of bigels as solid fat replacers and functional food ingredients. The hydrogel:oleogel ratio, selected gelators, inclusion of surfactants and encapsulation of molecules of interest, and process parameters (e.g., temperature, shear rate) during bigel production play a crucial role in the bigel's rheological and textural properties, microstructure, release characteristics, biocompatibility, and stability. Besides exploring the role of these parameters in bigel production, future research directions for bigels in a food context are explored.

Wheat milling across history altered sugar bioaccessibility assessed using TIM-1 in vitro digestion model.

The differences in wheat flour characteristics caused by ancient (pestle and mortar), old (stone hand mill), and modern (roller and cyclone) milling techniques and their effect on in vitro starch digestibility of wheat porridge using the simulated TIM Gastrointestinal Model (TIM-1) were investigated. Ancient flour (AF) was the coarsest flour (∼70 % is >1000 µm), followed by old wholemeal flour (OWF) and old refined flour (ORF) with similar particle size distribution showing one prominent peak (at ∼1000 µm for OWF and ∼800 µm for ORF). Modern refined flour (MRF) had a monomodal distribution centered at a particle size of ∼100 µm, while modern wholemeal flour (MWF) particle size was distributed between 40 and 600 µm. MRF and MWF porridges had higher cumulative sugar bioaccessibility than OWF and AF porridges, with ORF porridge having an intermediate cumulative sugar bioaccessibility. Characterizing the cumulative sugar bioaccessibility profile with a shifted logistic model allows identifying that the maximum sugar bioaccessibility and rate of sugar release were significantly higher (p < 0.05) for MRF and MWF compared to OWF and AF porridges, while the induction times were shorter, demonstrating the importance of processing on modulating starch digestibility.

The digestive fate of beef versus plant-based burgers from bolus to stool.

Ultra-processed, plant-based burgers (PB) and traditional comminuted-beef burgers (BB) share similar organoleptic characteristics, yet a knowledge gap exists in understanding how consumption of these divergent physical structures alters the lipemic response and gut microbiota. PB, comprised of highly refined ingredients, is formulated with no intact whole food structure, while BB entraps lipids throughout the myofibrillar protein network. PB presented significantly higher free fatty acid (FFA) bioaccessibility (28.2 ± 4.80 %) compared to BB (8.73 ± 0.52 %), as obtained from their FFA release profiles over digestion time after characterizing them with a modified logistic model (SLM), using the simulated TIM Gastro-Intestinal Model (TIM-1). Additionally, the rate of lipolysis, k, obtained from the SLM for PB (90% CI [0.0175, 0.0277] min-1) was higher than for BB (90% CI [0.0113, 0.0171] min-1). Using the Simulated Human Intestinal Microbial Ecosystem (SHIME®), the Firmicutes to Bacteroidetes ratio (F/B ratio) was significantly higher for PB than BB; and linear discriminant analysis effect size (LEfSe) showed Clostridium and Citrobacter were more highly represented in the microbial community for the PB feed, whereas BB feed differentially enriched Megasphaera, Bacteroides, Alistipes, and Blautia at the genus level. Additionally, short-chain fatty acid (SCFA) production was altered (p < 0.05) site-specifically in each colon vessel, which could be attributed to the available substrates and changes in microbial composition. Total SCFAs were significantly higher for PB in the ascending colon (AC) and descending colon (DC) but higher for BB only in the transverse colon (TC). This research illustrates the crucial role of meat analog physical structure in modulating nutritional aspects beyond food composition alone.

Mechanism of Synergistic Photoinactivation Utilizing Curcumin and Lauric Arginate Ethyl Ester against Escherichia coli and Listeria innocua.

This study investigated the mechanism of how lauric arginate ethyl ester (LAE) improves the photoinactivation of bacteria by curcumin after diluting the 100 µmol/L stock curcumin-LAE micelle solution to the concentration used during the treatment based on the curcumin concentration. The photoinactivation of bacteria was conducted by irradiating the 1 µmol/L curcumin-LAE solution containing cocktails of Escherichia coli and Listeria innocua strains (7 log CFU/mL) for 5 min with UV-A light (λ = 365 nm). The changes in solution turbidity, curcumin stability, and bacterial morphology, viability, and recovery were observed using SEM, TEM, and live/dead cell assays. The study found that LAE enhances the photoinactivation of bacteria by increasing the permeability of cell membranes which could promote the interaction of reactive oxygen species produced by photosensitized curcumin with the cell components. The combination of curcumin and LAE was demonstrated to be more effective in inhibiting bacterial recovery at pH 3.5 for E. coli, while LAE alone was more effective at pH 7.0 for L. innocua.

The Arrhenius equation revisited.

The Arrhenius equation has been widely used as a model of the temperature effect on the rate of chemical reactions and biological processes in foods. Since the model requires that the rate increase monotonically with temperature, its applicability to enzymatic reactions and microbial growth, which have optimal temperature, is obviously limited. This is also true for microbial inactivation and chemical reactions that only start at an elevated temperature, and for complex processes and reactions that do not follow fixed order kinetics, that is, where the isothermal rate constant, however defined, is a function of both temperature and time. The linearity of the Arrhenius plot, that is, Ln[k(T)] vs. 1/T where T is in °K has been traditionally considered evidence of the model's validity. Consequently, the slope of the plot has been used to calculate the reaction or processes' "energy of activation," usually without independent verification. Many experimental and simulated rate constant vs. temperature relationships that yield linear Arrhenius plots can also be described by the simpler exponential model Ln[k(T)/k(T(reference))] = c(T-T(reference)). The use of the exponential model or similar empirical alternative would eliminate the confusing temperature axis inversion, the unnecessary compression of the temperature scale, and the need for kinetic assumptions that are hard to affirm in food systems. It would also eliminate the reference to the Universal gas constant in systems where a "mole" cannot be clearly identified. Unless proven otherwise by independent experiments, one cannot dismiss the notion that the apparent linearity of the Arrhenius plot in many food systems is due to a mathematical property of the model's equation rather than to the existence of a temperature independent "energy of activation." If T+273.16°C in the Arrhenius model's equation is replaced by T+b, where the numerical value of the arbitrary constant b is substantially larger than T and T(reference), the plot of Ln k(T) vs. 1/(T+b) will always appear almost perfectly linear. Both the modified Arrhenius model version having the arbitrary constant b, Ln[k(T)/k(T(reference)) = a[1/ (T(reference)+b)-1/ (T+b)], and the exponential model can faithfully describe temperature dependencies traditionally described by the Arrhenius equation without the assumption of a temperature independent "energy of activation." This is demonstrated mathematically and with computer simulations, and with reprocessed classical kinetic data and published food results.

Vibrational and fluorescence spectroscopy to study gluten and zein interactions in complex dough systems.

The volume-spanning network formed by gluten during breadmaking is crucial in the production of high-quality bakery products. Zein proteins are also capable of forming a protein network under specific conditions. Vibrational (Fourier transform infrared spectroscopy (FTIR) and Raman scattering) and fluorescence spectroscopy are powerful, non-invasive techniques capable of assessing protein structures and interactions. The main objective of this project was to explore the suitability of these techniques to study zein and gluten structures and interactions in complex dough systems. The dough samples were prepared by mixing 20 w/w% of protein (with different proportions of zein and gluten) and 80 w/w% of corn starch. The tyrosine (Tyr) fluorescence emission peak (λexc = 280 nm) was still present even in those zein-gluten samples containing the highest gluten concentration and lowest zein concentration. This suggests that the Tyr moieties (stemming from zein) are not in close proximity to tryptophan (Trp) of gluten and their fluorescence is not quenched efficiently. Raman scattering results also showed the presence of different Tyr residues, exposed and buried, as well as different conformations of disulfide bridges, in zein and gluten samples. Based on the results from spectroscopic measurements and scanning electron microscopy (SEM), two distinct network structures composed of gluten and zein were identified in the mixed dough systems. The present work illustrates how complementary vibrational (Raman scattering and FTIR) and fluorescence spectroscopy methods can be combined to non-invasively assess protein structure and interactions in a complex food matrix.

Degradation kinetics of C-Phycocyanin under isothermal and dynamic thermal treatments.

C-Phycocyanin (C-PC) represents an alternative to artificial blue/green dyes in food products. This study characterized and gained insights into C-PC thermal stability mechanisms and provided a model to estimate its thermal degradation. Aqueous solutions of C-PC (0.3 µM, pH:6.1) were isothermally heated at 45-80 °C. C-PC degradation was monitored based on the photophysical properties of its lumiphores (phycocyanobilins and aromatic aminoacids-AAs). While C-PC was stable at 45 °C, less than 10 min at 80 °C sufficed to degrade most of it. The thermal degradation curves were characterized using the Weibull model, which was validated with data obtained under non-isothermal conditions. Deviations between estimated and experimental values were lower than 8%. Hypsochromic shifts of the AAs' spectra (from 340 to 315 nm) and increase (>30%) in anisotropy at λexc = 280 and 520 nm suggest that colour losses are not solely associated with alterations of the chromophore but also with conformational changes and possible aggregation of the protein subunits.

Role of Solid Fat Content in Oxidative Stability of Low-Moisture Cracker Systems.

Lipid oxidation is a major pathway for the chemical deterioration of low-moisture foods. Little is known about how the physical properties of the fat used in crackers impact lipid oxidation kinetics. Fully hydrogenated soybean fat + interesterified soybean oil, fully hydrogenated soybean fat + sunflower oil, fully hydrogenated soybean oil, and soybean oil and interesterified fat alone were formulated to have varying solid fat content (SFC) at 55 °C but the same linoleic acid and tocopherol contents, so the fats had similar susceptibility to oxidation. A fluorescence probe showed that lipid mobility increased with decreasing SFC in both cracker doughs and fat blends, suggesting the probe could be used to monitor SFC directly in foods. Decreasing SFC decreased oxidation in crackers. Crackers made from interesterified fat (13.7% SFC) were more oxidatively stable (hexanal lag phase = 33 days) than crackers made from fat blends (hexanal lag phase = 24 days). These results suggest that blended fats result in regions of liquid oil high in unsaturated fatty acids within a food product prone to oxidation. Conversely, interesterified fats where unsaturated and saturated fatty acids are more evenly distributed on the triacylglycerols are more stable. Thus, interesterified fats could allow for the formulation of products higher in unsaturated fatty acids to improve nutritional profiles without sacrificing shelf life.

Expanded Fermi solution for estimating the survival of ingested pathogenic and probiotic microbial cells and spores.

The expanded Fermi solution was originally developed for estimating the number of food-poisoning victims when information concerning the circumstances of exposure is scarce. The method has been modified for estimating the initial number of pathogenic or probiotic cells or spores so that enough of them will survive the food preparation and digestive tract's obstacles to reach or colonize the gut in sufficient numbers to have an effect. The method is based on identifying the relevant obstacles and assigning each a survival probability range. The assumed number of needed survivors is also specified as a range. The initial number is then estimated to be the ratio of the number of survivors to the product of the survival probabilities. Assuming that the values of the number of survivors and the survival probabilities are uniformly distributed over their respective ranges, the sought initial number is construed as a random variable with a probability distribution whose parameters are explicitly determined by the individual factors' ranges. The distribution of the initial number is often approximately lognormal, and its mode is taken to be the best estimate of the initial number. The distribution also provides a credible interval for this estimated initial number. The best estimate and credible interval are shown to be robust against small perturbations of the ranges and therefore can help assessors achieve consensus where hard knowledge is scant. The calculation procedure has been automated and made freely downloadable as a Wolfram Demonstration.