SciCombinator

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Concept: Food preservation

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Micellar electrokinetic capillary chromatography with electrochemical detection has been used to quantify biogenic amines in freeze-dried Drosophila melanogaster brains. Freeze drying samples offers a way to preserve the biological sample while making dissection of these tiny samples easier and faster. Fly samples were extracted in cold acetone and dried in a rotary evaporator. Extraction and drying times were optimized in order to avoid contamination by red-pigment from the fly eyes and still have intact brain structures. Single freeze-dried fly-brain samples were found to produce representative electropherograms as a single hand-dissected brain sample. Utilizing the faster dissection time that freeze drying affords, the number of brains in a fixed homogenate volume can be increased to concentrate the sample. Thus, concentrated brain samples containing five or fifteen preserved brains were analyzed for their neurotransmitter content, and five analytes; dopamine N-acetyloctopamine, N-acetylserotonin, N-acetyltyramine, N-acetyldopamine were found to correspond well with previously reported values.

Concepts: Vacuum, Sublimation, Micellar electrokinetic chromatography, Freeze drying, Food preservation

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Red beet plants are rich in betalains that can be used as food natural colorants. Betalains were extracted from red beet and encapsulated with different carrier agents and freeze or spray dried. Effect of different encapsulating agents as maltodextrin, guar gum, gum Arabic, pectin and xanthan gum with different concentration (as encapsulating agents) were studied on the betalain stability. Encapsulated betalains with xanthan gum with maltodextrin showed about 65 % more recovery than the control. Encapsulation showed a higher recovery of betalains during freeze drying by 1.3 times than during spray drying. Spray dried samples has L* (lightness) higher than the freeze dried samples. The variations of maltodextrin with xanthan and guar gum freeze dried have highest chroma value of 21. The stabilization of pure betalain pigments may boost the use of these colouring molecules in the food industry and promote their application.

Concepts: Betalain, Instant coffee, Beet, Guar gum, Gums, Food preservation, Freeze drying, E number

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Sperm preservation is an important technique for maintaining valuable genetic resources in biomedical research and wildlife. In the mouse, the sperm cryopreservation method has been established and adopted by large-scale sperm preservation projects in cryobanks. Recently, a new sperm preservation method using freeze-drying has been studied in various mammals. Freeze-drying is the ultimate method by which sperm can be preserved long term in a refrigerator (4 °C). And it is possible to realize easy and safe transportation of sperm at an ambient temperature that requires neither liquid nitrogen nor dry ice. Furthermore, it has been demonstrated that the fertilizing ability of sperm cryopreserved or freeze-dried by the methods described in this chapter is well maintained during long-term preservation. This chapter introduces the latest protocols for cryopreservation and freeze-drying of mouse sperm, and the anticipated results of the fertilizing ability of these sperm preserved long-term.

Concepts: Cryogenics, Cryonics, Nitrogen, Cryopreservation, Term, Sublimation, Food preservation, Liquid nitrogen

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Food product reformulation is seen as one among several tools to promote healthier eating. Reformulating the recipe for a processed food, e.g. reducing the fat, sugar or salt content of the foods, or increasing the content of whole-grains, can help the consumers to pursue a healthier life style. In this study, we evaluate the effects on calorie sales of a ‘silent’ reformulation strategy, where a retail chain’s private-label brands are reformulated to a lower energy density without making specific claims on the product.

Concepts: Food preservation, Flavor, Sugar, Supermarket, Retailing, Carbohydrate, Nutrition, Food

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Platonin possesses potent anti-inflammatory and antioxidative capacities. Because systemic inflammation and oxidative stress are crucial in mediating sepsis-induced blood-brain barrier (BBB) integrity loss, this study elucidated the effects of platonin on preserving BBB integrity in septic rats.

Concepts: Anti-inflammatory, Food preservation, Antioxidant, Oxidative phosphorylation, Oxidative stress, Sepsis, Inflammation

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The economic burdens and health implications of food spoilage are increasing. Contamination of food sources by fungi, bacteria, yeast, nematodes, insects, and rodents remains a major public health concern. Research has focused on developing safer natural products and innovations to meet consumers' acceptance as alternatives to synthetic food preservatives. Many recent novel preservative techniques and applications of both natural and synthetic origin continue to proliferate in food and chemical industries. In particular, some essential oils of plant origin are potent food preservatives and are thus attractive alternatives to synthetic preservatives. This paper provides an overview of recent advances and future prospects in assessing the efficacy of theuse of Cymbopogon citratus (lemongrass) essential oil in food preservation. The possible mechanisms of action and toxicological profile as well as evidence for or against the use of this essential oil as an alternative to synthetic food preservatives in domestic and industrial applications are discussed.

Concepts: Food, Oils, Oil, Cymbopogon citratus, Preservative, Essential oil, Cymbopogon, Food preservation

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Nisin is a natural preservative for many food products. This bacteriocin is mainly used in dairy and meat products. Nisin inhibits pathogenic food borne bacteria such as Listeria monocytogenes and many other Gram-positive food spoilage microorganisms. Nisin can be used alone or in combination with other preservatives or also with several physical treatments. This article reviews physicochemical and biological properties of nisin, the main factors affecting its antimicrobial effectiveness, and its food applications as an additive directly incorporated into food matrices.

Concepts: Organism, Natural selection, Food additive, Listeria, Listeria monocytogenes, Food preservation, Bacteria, Microbiology

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The production of long shelf-life highly concentrated dried probiotic/starter cultures is of paramount importance for the food industry. The aim of the present study was to evaluate the protective effect of glucose, lactose, trehalose, and skim milk applied alone or combined upon the survival of potentially probiotic Lactobacillus rhamnosus CTC1679, Lactobacillus casei/paracasei CTC1677 and L. casei/paracasei CTC1678 during freeze-drying and after 39 weeks of storage at 4 and 22 °C. Immediately after freeze-drying, the percentage of survivors was very high (≥94%) and only slight differences were observed among strains and cryoprotectants. In contrast, during storage, survival in the dried state depended on the cryoprotectant, temperature and strain. For all the protectants assayed, the stability of the cultures was remarkably higher when stored under refrigeration (4 °C). Under these conditions, skim milk alone or supplemented with trehalose or lactose showed the best performance (reductions ≤0.9 log units after 39 weeks of storage). The lowest survival was observed during non-refrigerated storage and with glucose and glucose plus milk; no viable cells left at the end of the storage period. Thus, freeze-drying in the presence of appropriate cryoprotectants allows the production of long shelf-life highly concentrated dried cultures ready for incorporation in high numbers into food products as starter/potential probiotic cultures.

Concepts: Food, Freeze drying, Milk, Cryoprotectant, Food preservation, Lactobacillus rhamnosus, Trehalose, Probiotic

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The use of co-solvent systems has been demonstrated to shorten lengthy freeze drying processes and improve the solubility and stability of certain active pharmaceutical ingredients. The goal of the present study was to evaluate the suitability of two thermal characterization techniques, differential scanning calorimetry and freeze dry microscopy, to identify an optimal co-solvent system. Binary mixtures of a co-solvent (tert-butanol, dimethyl sulfoxide, 1,4-dioxane, acetone or ethanol) and water were investigated. Ternary mixtures of frequently used excipients (50 mg/g mannitol, sucrose, glycine or polyvinylpyrrolidone) and a solvent-water system were then analyzed for their thermal properties. PVP presented a particularly high glass transition temperature (Tg') in 70% TBA at -17.9°C. Large needle-shaped crystals that have been shown to be associated with improved processability were observed with mannitol and PVP in 40% 1,4-dioxane. A heterogeneous sublimation rate of the solvent and water whose impact on product stability remained unclear was observed with PVP in 40% 1,4-dioxane. FDM analysis demonstrated a possible extension of the process time for PVP in 99% DMSO due to a slowly moving sublimation front. Conceivable negative consequences and the need for special treatment for low melting co-solvents, such as ethanol and acetone, were predicted and discussed.

Concepts: Food preservation, Materials science, Melting point, Sublimation, Glass transition, Solvent, Freeze drying, Differential scanning calorimetry

14

Field studies of wild vertebrates are frequently associated with extensive collections of banked fecal samples-unique resources for understanding ecological, behavioral, and phylogenetic effects on the gut microbiome. However, we do not understand whether sample storage methods confound the ability to investigate interindividual variation in gut microbiome profiles. Here, we extend previous work on storage methods for gut microbiome samples by comparing immediate freezing, the gold standard of preservation, to three methods commonly used in vertebrate field studies: lyophilization, storage in ethanol, and storage in RNAlater. We found that the signature of individual identity consistently outweighed storage effects: alpha diversity and beta diversity measures were significantly correlated across methods, and while samples often clustered by donor, they never clustered by storage method. Provided that all analyzed samples are stored the same way, banked fecal samples therefore appear highly suitable for investigating variation in gut microbiota. Our results open the door to a much-expanded perspective on variation in the gut microbiome across species and ecological contexts.

Concepts: Vertebrate, Measurement of biodiversity, Alpha diversity, Evolution, Food preservation, Species, Biodiversity, Gut flora