Understanding taste is key for optimizing the palatability of seaweeds and other non-animal-based foods rich in protein. The lingual papillae in the mouth hold taste buds with taste receptors for the five gustatory taste qualities. Each taste bud contains three distinct cell types, of which Type II cells carry various G protein-coupled receptors that can detect sweet, bitter, or umami tastants, while type III cells detect sour, and likely salty stimuli. Upon ligand binding, receptor-linked intracellular heterotrimeric G proteins initiate a cascade of downstream events which activate the afferent nerve fibers for taste perception in the brain. The taste of amino acids depends on the hydrophobicity, size, charge, isoelectric point, chirality of the alpha carbon, and the functional groups on their side chains. The principal umami ingredient monosodium l-glutamate, broadly known as MSG, loses umami taste upon acetylation, esterification, or methylation, but is able to form flat configurations that bind well to the umami taste receptor. Ribonucleotides such as guanosine monophosphate and inosine monophosphate strongly enhance umami taste when l-glutamate is present. Ribonucleotides bind to the outer section of the venus flytrap domain of the receptor dimer and stabilize the closed conformation. Concentrations of glutamate, aspartate, arginate, and other compounds in food products may enhance saltiness and overall flavor. Umami ingredients may help to reduce the consumption of salts and fats in the general population and increase food consumption in the elderly.
MULTIFILE
Carnitine/choline acyltransferases play diverse roles in energy metabolism and neuronal signalling. Our knowledge of their evolutionary relationships, important for functional understanding, is incomplete. Therefore, we aimed to determine the evolutionary relationships of these eukaryotic transferases. We performed extensivephylogenetic and intron position analyses. We found that mammalian intramitochondrial CPT2 is most closely related to cytosolic yeast carnitine transferases (Sc-YAT1 and 2), whereas the other members of the family are related to intraorganellar yeast Sc-CAT2. Therefore, the cytosolically active CPT1 more closely resembles intramitochondrial ancestors than CPT2. The choline acetyltransferase is closely related to carnitine acetyltransferase and shows lower evolutionary rates than long chain acyltransferases. In the CPT1 family several duplications occurred during animal radiation, leading to the isoforms CPT1A, CPT1B and CPT1C. In addition, we found five CPT1-like genes in Caenorhabditis elegans that strongly group to the CPT1 family. The long branch leading to mammalian brain isoform CPT1C suggests that either strong positive or relaxed evolution has taken place on this node. The presented evolutionary delineation of carnitine/choline acyltransferases adds to current knowledge on their functions and provides tangible leads for further experimental research.
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Due to a growing challenge to feed the world’s population and an increased awareness to minimize the impact of our food choices on climate change, a more plant-based diet has gained popularity with a growing number of plant-based products on the market. To stimulate a plant-based diet that also improves long-term health, data are needed to monitor whether these products are healthy alternatives to animal-based foods. Therefore, this study inventoried 916 plant-based meat, fish, and dairy alternatives from eight Dutch supermarkets. The nutritional quality of each product was assessed by (1) the Dutch food-based dietary guidelines and (2) the Nutri-Score. The results show that over 70% of meat, fish, and dairy alternatives have an A/B Nutri-Score (indicating high nutritional quality), but do not comply with the Dutch dietary guidelines. This is mainly due to high salt and low vitamin B12 and iron content (meat and fish alternatives) or low protein and calcium levels (dairy alternatives). In conclusion, the majority of plant-based products are nutritionally not full alternatives of the animal-based equivalents; however, there are still opportunities for reformulation. To aid the consumer in making healthy plant-based food choices, a better alignment between the Nutri-Score and the recommended dietary guidelines is needed.
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Penicillin acylase (PA) from Escherichia coli can catalyze the coupling of an acyl group to penicillin- and cephalosporin-derived beta-lactam nuclei, a conversion that can be used for the industrial synthesis of beta-lactam antibiotics. The modest synthetic properties of the wild-type enzyme make it desirable to engineer improved mutants. Analysis of the crystal structure of PA has shown that residues alphaR145 and alphaF146 undergo extensive repositioning upon binding of large ligands to the active site, suggesting that these residues may be good targets for mutagenesis aimed at improving the catalytic performance of PA. Therefore, site-saturation mutagenesis was performed on both positions and a complete set of all 38 variants was subjected to rapid HPLC screening for improved ampicillin synthesis. Not less than 33 mutants showed improved synthesis, indicating the importance of the mutated residues in PA-catalyzed acyl transfer kinetics. In several mutants at low substrate concentrations, the maximum level of ampicillin production was increased up to 1.5-fold, and the ratio of the synthetic rate over the hydrolytic rate was increased 5-15-fold. Moreover, due to increased tendency of the acyl-enzyme intermediate to react with beta-lactam nucleophile instead of water, mutants alphaR145G, alphaR145S and alphaR145L demonstrated an enhanced synthetic yield over wild-type PA at high substrate concentrations. This was accompanied by an increased conversion of 6-APA to ampicillin as well as a decreased undesirable hydrolysis of the acyl donor. Therefore, these mutants are interesting candidates for the enzymatic production of semi-synthetic beta-lactam antibiotics.
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from the article: "Cow's milk-derived whey hydrolysates are milk substitutes for cow's milk allergic infants. Safety assessment of these hydrolysates is crucial. Currently, huFcεRIα-RBL-2H3 cells, sensitized with serum IgE from cow's milk allergic patients, are used to assess in vitro residual allergenicity. However, limited availability and high inter-lot variation of sera impede the standardization of safety testing. Recently, we generated an oligoclonal pool of chimeric human (chu)IgE antibodies against bovine β-lactoglobulin (BLG) as an alternative for human serum. These antibodies demonstrated increased sensitivity, specificity and reproducibility. An inter-laboratory ring trial using our new degranulation assay with different whey-based hydrolysates was performed at four independent laboratories to investigate the robustness and reproducibility. RBL-2H3 cells expressing huFcεRIα were sensitized with our oligoclonal pool of anti-BLG chuIgE antibodies. The cells were subsequently incubated with an amino-acid based formula (AAF), two extensively hydrolyzed formulas (eHF) and three partially hydrolyzed formulas (pHF) to assess the degranulation upon challenge. Results demonstrated a very strong inter-laboratory correlation and the intra- and inter-laboratory variations were acceptable. The AAF and both eHFs showed no degranulation, whereas all pHFs demonstrated degranulation. The study showed that this degranulation assay is robust and reproducible within and between laboratories. This new in vitro degranulation assay seems predictive for allergenicity outcome and might therefore be considered as a relevant substitute for animal models."
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Presentatie van de eerste resultaten van de in vivo studies met vleeskuikens waarin gestreefd wordt naar een meer duurzame en diervriendelijke pluimveehouderij, tijdens de European Poultry Conference (EPC) in Valencia.
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Due to the environmental and nutritional benefits of insects, their consumption would be one of the solutions to feed the growing human population. Despite the increasing interest in the use of insects as food and feed, consumer acceptance is the major obstacle to successful implementation in Western countries and we studied the factors that influence consumer acceptance in a group of university students from Germany and the Netherlands. In this exploratory research, a survey was conducted (n = 222). Socio‐demographic and psychological factors were established from a theoretical review. In addition, we elaborated on questions regarding information on the health and environmental benefits of consuming insects. Initially, the data obtained are presented through descriptive statistics. The influence of the socio‐demographic and psychological factors, and the information on the willingness to accept insects as animal feed and human food was analyzed using correlations and multiple linear regressions. Results showed more willingness to accept insects as animal feed than in human food. The acceptance among German and Dutch students seems to be driven by issues similar to those in other European countries, such as visual aspects and knowledge about the benefits. The effect of the information on willingness constitutes an important finding of this study, especially for the use of insects in animal feed, since most of the previous studies have focused on the use of insects as human food. Our data support the need to inform and educate consumers about the environmental and health benefits of entomophagy. We conclude that effective efforts to implement entomophagy could increase the level of familiarity with the insect food and inform (or educate) consumers about its benefits. Insights from this study are useful to address studies focusing on specific segments of possible early adopters and consequently addressing communication strategies in this market segmentation.
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