Astaxanthin is a carotenoid widely used in salmonid and crustacean aquaculture to provide the pink color characteristic of that species. This application has been well documented for over two decades and is currently the major market driver for the pigment. Additionally, astaxanthin also plays a key role as an intermediary in reproductive processes. Synthetic astaxanthin dominates the world market but recent interest in natural sources of the pigment has increased substantially. Common sources of natural astaxanthin are the green algae Haematococcus pluvialis, the red yeast, Phaffia rhodozyma, as well as crustacean byproducts. Astaxanthin possesses an unusual antioxidant activity which has caused a surge in the nutraceutical market for the encapsulated product. Also, health benefits such as cardiovascular disease prevention, immune system boosting, bioactivity against Helycobacter pylori, and cataract prevention, have been associated with astaxanthin consumption. Research on the health benefits of astaxanthin is very recent and has mostly been performed in vitro or at the pre-clinical level with humans. This paper reviews the current available evidence regarding astaxanthin chemistry and its potential beneficial effects in humans.
A molecularly imprinted material was developed from hydrogels of chitosan (CS) cross-linked with genipin (GNP) using o-xylene as the template molecule. Gelling time, mechanical, and diffusion properties of CS-GNP hydrogels were initially investigated to establish optimal conditions to prepare molecularly imprinted hydrogels (MIHs). The elastic modulus was found to be directly proportional to the degree of cross-linking (R = moles of genipin/moles of glucosamine) while the diffusion of water, as monitored by magnetic resonance imaging, decreased with R. CS-GNP hydrogels of varying R were imprinted with o-xylene (MIH(o-xylene)). The adsorption capacity of o-xylene by MIH(o-xylene) was greater than the corresponding control hydrogels, particularly at R = 0.25. Freundlich isotherms yielded a better fitness than Langmuir ones and afforded n and Q(max)values of 2.55 and 103.3 mg/g, respectively. The imprinted hydrogel showed the highest adsorption capacity for o-xylene; however, the material was not highly selective as it also exhibited the capacity to adsorb m- and p-xylene isomers. In turn, the MIH(o-xylene) showed a low adsorption when 2-fluorotoluene was used in rebinding experiments, suggesting that molecular recognition by the binding sites is influenced by the electronic and steric properties of the analyte molecule, thus effectively confirming the imprinting effect within the MIH(o-xylene) network. This work opens the possibility to future development of materials with the capacity to adsorb o-xylene analogue molecules such as contaminants bearing chlorinated aromatic structures.
Astaxanthin (AX) is the major naturally occurring carotenoid pigment in marine crustaceans and the flesh of salmonids. These organisms are unable to synthesize AX de novo and when farmed commercially, require it in their feed. The high cost of synthetic AX has promoted research into new natural sources of ihe pigment, such as crustacean wastes. In this work, AX from demineralized crab (Callinectes sapidusj shell waste was extracted with a mixture of supercritical C2 and ethanol as a cosolvent. The effect of total solids load, pressure and temperature was assessed by response surface methodology (RSM). Extracted AX was determined by HPLC. The experimental data were fined to a second order model whereby the conditions for maximum extraction yield were defined (≥ 34 MPa, 45C and solids load of 25 g). Pressure and solids load were the most important factors affecting AX extraction yields.
Food‐borne outbreaks caused by virus have been associated with the consumption of fresh produce. However, it is difficult to track the source of contamination due to the lack of sensitive methods of detection. In this study, we evaluated the presence of norovirus (NoV), rotavirus (RV) and hepatitis A virus (HAV) in fresh produce from the northwestern part of Mexico by reverse transcription quantitative PCR (RT‐qPCR). Fresh produce was sampled from field and packinghouse facilities during different stages of the packing process. Surfaces of equipment, as well as water used for disinfection were also sampled. A total of 46 samples were analyzed for the quantification of virus: HAV was found in 28.2% of the samples, NoV in 32.6% and RV in 13.0%. Eleven samples were positive with at least two different viruses. These results show a high prevalence of these viruses in fresh produce and highlight the need to establish further virological surveys for this kind of products. Practical Applications Viruses are considered important causal agents of food‐borne diseases. Many outbreaks implicate the consumption of fresh produce, mainly because fresh vegetables are usually consumed raw or with minimum processing. In spite of this, in many undeveloped countries, analyses for microbial quality imply testing for bacterial but not for viruses' contamination. For that reason, it is necessary to generate information on the risk of virus transmission in fresh produce. In that way, producers can be warned of the risk of virus contamination, and they could implement good manufacturing practices to improve sanitary conditions in fresh produce processing plants for consumer protection to diminish food‐borne outbreaks. We evaluated the prevalence of enteric viruses in fresh produce, water and surfaces of equipment by reverse transcriptase quantitative PCR, a sensitive method not commonly used for sanitary monitoring of food products.
In Mexico, group A rotavirus (RVA) infections remain the most common cause of severe dehydrating diarrhea in children. This study was conducted to examine the circulating RVA strains in the northwest region of Mexico. RVA strains collected from stool samples of children were genotyped, and their partial sequences were analyzed. RT-PCR of the VP4 and VP7 genes showed the partial G9P[4] genotype in all the samples. Sequencing and phylogenetic analysis of the partial VP7 gene amplicons of 10 strains showed that they clustered in the RVA G9 lineage III, and 7 of them showed 100% identity with the reference strain LB1562, which was collected in the USA 2 years earlier. The amino acid sequences of the VP7 and VP4 antigenic regions were highly conserved between the analyzed RVA strains. Active surveillance is important for monitoring the emergence of RVA strains and their impact on cases of gastroenteritis.
Norovirus (NoV) is an important etiological agent of diarrhea in children and adults. In Mexico, NoV screening is not routinely performed. NoV is highly infectious and is responsible for massive outbreaks due to the consumption of contaminated food. The study was a cross-sectional design. Samples of diarrheal stools were collected from (62) children and ( 38) adults with acute gastroenteritis during 2013-2014. The circulating genogroups of NoV were detected by amplifying the RdRp gene fragment, and for the genotyping, the capsid and polymerase fragments were sequenced. Seventy-seven percent of the analyzed samples were positive for NoV. Genotyping was possible for 51 samples; for polymerase GII.P2, GII.P31, GII.P4, GII.P7, GII.P40, and GI.P14 were identified, whereas for capsid, genotypes GI.3, GII.2, GII.4, GII.5, GII.14, and GII.17. In conclusion, there is a high prevalence of gastroenteritis due to NoV in the northwest of Mexico, including genotypes that have not been reported previously in Mexico.
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