Umami, as an alimentary taste, is an indicator for the presence of valuable amino acids or oligopeptides. Umami substances, including free amino acids, nucleotides, peptides, organic acids and their ...derivatives, are widely distributed in foods. They usually improve the overall taste of food such as modulating sweet taste, enhancing salty taste and suppressing sourness and bitterness. Though umami receptors have been discovered, the evaluation of umami intensity with sensitivity and selectivity is nevertheless a challenge because of its multivariate taste characteristics in complex food matrix source. Based on the available literature, this review summarized the distribution traits in food sources, taste characteristics, evaluation approaches and the related investigations. In further studies, with advance in the field of materials, microfluidic and nano-technologies, new evaluation approaches should be designed with the advantages of fast, sensitive and selective, and allowing more structurally versatile umami (enhancing) ingredients would be elucidated from raw food materials.
•Umami as an alimentary taste is the indicator for amino acids or oligopeptides.•Umami can modulate sweet taste, enhance salty taste and suppress bitterness.•The different evaluation modes of umami molecules were summarized.•Fermentation and biosynthesis would enhance umami ingredient yield in further.•New biosensor would make umami evaluation more sensitive and accurate.
Vitamin B12 is synthesized only by certain bacteria and archaeon, but not by plants. The synthesized vitamin B12 is transferred and accumulates in animal tissues, which can occur in certain plant and ...mushroom species through microbial interaction. In particular, the meat and milk of herbivorous ruminant animals (e.g. cattle and sheep) are good sources of vitamin B12 for humans. Ruminants acquire vitamin B12, which is considered an essential nutrient, through a symbiotic relationship with the bacteria present in their stomachs. In aquatic environments, most phytoplankton acquire vitamin B12 through a symbiotic relationship with bacteria, and they become food for larval fish and bivalves. Edible plants and mushrooms rarely contain a considerable amount of vitamin B12, mainly due to concomitant bacteria in soil and/or their aerial surfaces. Thus, humans acquire vitamin B12 formed by microbial interaction via mainly ruminants and fish (or shellfish) as food sources. In this review, up-to-date information on vitamin B12 sources and bioavailability are also discussed.
Impact statement
To prevent vitamin B12 (B12) deficiency in high-risk populations such as vegetarians and elderly subjects, it is necessary to identify foods that contain high levels of B12. B12 is synthesized by only certain bacteria and archaeon, but not by plants or animals. The synthesized B12 is transferred and accumulated in animal tissues, even in certain plant tissues via microbial interaction. Meats and milks of herbivorous ruminant animals are good sources of B12 for humans. Ruminants acquire the essential B12 through a symbiotic relationship with bacteria inside the body. Thus, we also depend on B12-producing bacteria located in ruminant stomachs. While edible plants and mushrooms rarely contain a considerable amount of B12, mainly due to concomitant bacteria in soil and/or their aerial surfaces. In this mini-review, we described up-to-date information on B12 sources and bioavailability with reference to the interaction of microbes as B12-producers.
The continuous detection of multi-drug-resistant enterococci in food source environments has aroused widespread concern. In this study, 198 samples from chicken products, animal feces, raw milk, and ...vegetables were collected in Japan and Egypt to investigate the prevalence of enterococci and virulence characterization. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was employed for species identification and taxonomic analysis of the isolates. The results showed that the rates of most virulence genes (efaA, gelE, asa1, ace, and hyl) in the Japanese isolates were slightly higher than those in the Egyptian isolates. The rate of efaA was the highest (94.9 %) among seven virulence genes detected, but the cylA gene was not detected in all isolates, which was in accordance with γ-type hemolysis phenotype. In Enterococcus faecalis, the rate of kanamycin-resistant strains was the highest (84.75 %) among the antibiotics tested. Moreover, 78 % of E. faecalis strains exhibited multi-drug resistance. Four moderately vancomycin-resistant strains were found in Egyptian isolates, but none were found in Japanese isolates. MALDI-TOF MS analysis correctly identified 98.5 % (68/69) of the Enterococcus isolates. In the principal component analysis dendrogram, strains isolated from the same region with the same virulence characteristics and similar biofilm-forming abilities were characterized by clustered distribution in different clusters. This finding highlights the potential of MALDI-TOF MS for classifying E. faecalis strains from food sources.
•77.1 % of raw chicken, raw milk and compost were positive for Enterococcus in Japan.•20 % of food source derived samples were positive for Enterococcus in Egypt.•78 % of the E. faecalis isolates showed multi-drug resistance.•efaA was positive for 94.9 % of the isolates among 7 virulence genes tested.•PCA classified strains by same region, virulence trait and biofilm-forming ability
The cotton boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is one of the most important insect pests of cotton, causing significant yield losses. This insect completes ...its life cycle only on the flower structures of some Malvaceae species, with cotton being its preferred host. However, during the cotton off‐season, the boll weevil enters a reproductive dormancy state, in tropical regions, with important alterations in their reproduction organs. During this period, a remaining insect population survives feeding on a variety of other food sources, but the insects do not reproduce. We hypothesized that these alterations in the insect's reproductive organs are associated with the nutritional levels provided by alternative food sources during the cotton off‐season. To test our hypothesis, we first investigated food sources that sustain insect survival for long periods, such as weed species and fruits of cultivated crops. Then, we evaluated how various food sources affect the reproductive organs and reproductive capacity of the boll weevil. Among the alternative food sources tested, insect longevity was highest on banana (Musa paradisiaca L.), mango (Mangifera indica L.), papaya (Carica papaya L.), milkweed (Euphorbia heterophylla L.), and lilac tasselflower (Emilia sonchifolia L.). However, only banana and mango resulted in greater longevity than cotton squares. Banana was the preferred food and resulted in the highest levels of nutrients in the insects. Additionally, insects previously fed on banana made more oviposition punctures on cotton squares than those fed only on cotton squares, which resulted in a significantly higher number of emerged adults. Histological analysis of the insects' reproductive organs showed that feeding on papaya resulted in morphological changes and testicle degradation. In conclusion, we present evidence that boll weevils fed on alternative food sources (other than cotton squares or similar‐quality food) display a nutritional imbalance, associated with substantial alterations in the reproductive tissues of this insect, which may trigger the reproductive dormancy state.
Anthonomus grandis (Coleoptera: Curculionidae) feeds preferentially on cotton and completes its cycle only on a few plants of the Malvaceae family. However, this insect survives the cotton off‐season period feeding on other plant species, such as cultivated fruits or weed flowers. These insects survived longer and preferred banana over cotton squares. When they fed on low‐nutritional food (e.g., papaya fruit), their reproductive organs (testicles and oocytes) showed an abnormal morphology, which impaired their ability to lay viable eggs.
Wild-growing edible flora should be investigated to improve human food sustainability and security. Portulacaria afra (spekboom) is an undervalued edible succulent plant that thrives in harsh ...conditions in Southern Africa. This study determined whether the indigenous edible spekboom can be harnessed as a sustainable, nutritious food source and ingredient. Physicochemical and nutritional analyses were conducted on fresh and processed leaves (preserves, chutney, pickles, and spice). The physicochemical characteristics included morphology, color, texture, °Brix, pH, water activity, moisture content, titratable acidity, and ascorbic acid. Nutritional value determinants included crude protein, crude fiber, gross energy, and total fat content. The small, dark green fresh leaves had a soft texture and a very low sugar and fat content. Although the water content was high, water activity was low. The pH and titratable acidity showed high acidity. Leaves were high in ascorbic acid and low in protein, energy, insoluble fiber, and total fats. The leaves were successfully processed into preserved products providing possible applications in the food industry other than fresh leaves. The high acidity could be researched for application as a functional ingredient. This study provided basic information on an unexplored plant that may have potential in the food industry.
Habitat-use and distribution models are essential tools of conservation biology. For wide-ranging species, such models may be challenged by the expanse, remoteness and variability of their habitat, ...these challenges often being compounded by the species’ mobility. In marine environments, direct observations and sampling are usually impractical over broad regions, and instead remotely sensed proxies of prey availability are often used to link species abundance or foraging behaviour to areas that are expected to provide food consistently. One source of food consumed by many marine top predators is fisheries waste, but habitat-use models rarely account for this interaction. We assessed the utility of commercial fishing effort as a covariate in foraging habitat models for northern fulmars
Fulmarus glacialis
, a species known to exploit fisheries waste, during their summer breeding season. First, we investigated the prevalence of fulmar-vessel interactions using concurrently tracked fulmars and fishing vessels. We infer that over half of our study individuals associate with fishing vessels while foraging, mostly with trawl-type vessels. We then used hidden Markov models to explain the spatio-temporal distribution of putative foraging behaviour as a function of a range of covariates. Persistent commercial fishing effort was a significant predictor of foraging behaviour, and was more important than commonly used environmental covariates retained in the model. This study demonstrates the effect of commercial fisheries on the foraging distribution and behaviour of a marine top predator, and supports the idea that, in some systems, incorporating human activities into distribution studies can improve model fit substantially.
Mangrove forests are productive habitats and major potential exporters of organic matter and nutrients to adjacent habitats. Here we examine the extent to which mangrove carbon is transferred to ...adjacent intertidal food webs in the second largest mangrove-covered area in Africa, in Guinea-Bissau. Applying stable isotope analysis and mixing models, we made comparisons at two spatial scales: (1) a large scale, comparing intertidal flats with (mangrove sites) and without (control sites) adjacent mangrove forests regarding the carbon isotopic signature of macrozoobenthos and sediment organic matter (SOM), and the relative importance of potential primary food sources in sustaining macrozoobenthos, and (2) a fine scale, performing stable carbon isotope measurements along 200 m transects from the coastline out to open intertidal flats, to trace mangrove carbon in macrozoobenthos and in the SOM. We found no evidence that mangrove carbon sustains intertidal food webs, despite SOM being significantly more depleted in 13C in mangrove sites. Mangrove leaves had the lowest relative contribution to the diet of macrozoobenthos, while macroalgae, benthic microalgae and POM showed variable but overall relevant contributions. Yet, at a smaller scale, mangrove carbon was detectable in SOM and in most macrozoobenthos, being strongest within 50 m of the mangrove edge and quickly fading with increasing distance. Our results suggest that there is only a marginal input of mangrove carbon into the food webs of unvegetated intertidal flats. Still, this leaves open the possibility of mangrove forests acting as sources of dissolved inorganic carbon and processed nitrogen, which can be assimilated by the algae and subsequently fuel adjacent food webs.
•Mangrove carbon was not an important source for adjacent intertidal communities.•Sediments adjacent to mangrove stands had modest contributions from mangrove leaves.•Macroalgae, particulate organic matter and microalgae were the important sources.•Mangrove carbon was only detectable within 50 m from the mangrove fringe.•Alternatively, mangroves may act as providers of inorganic carbon and nutrients.
Holothurians are one of the key components of the deep-sea megabenthos, often forming significant aggregations with high abundance and biomass. The crucial factors determining the pattern of their ...spatial distribution might be their food strategies, as well as the quantity and quality of available food. Using the set of trophic markers (analysis of fatty acid (FA) composition and stable nitrogen and carbon isotope signatures), we studied the trophic preferences of four common species of deep-sea holothurians (Paelopatides sp., Pannychia henrici, Psolidium sp., and Scotoplanes kurilensis) inhabiting the Volcanologists Massif, Bering Sea, at depths from 984 m to 3395 m. The δ13С values in tissues of all four species varied slightly (from −16.2 to −16.6‰) and were significantly higher than those in sediment organic matter (SOM) (on average, −21.5‰), which indicates the use of organic matter of the same origin by all species. The δ15N values (10.1–12.9‰) were also significantly higher than in SOM (on average, 4.4‰). The lowest average δ15N value was recorded for the deepest-dwelling species (Scotoplanes kurilensis), and the highest value from the shallowest-dwelling ones (Psolidium sp.). All the species differed significantly in FA composition. Psolidium sp. was distinguished by the highest saturated FA content (45.5%) and the lowest polyunsaturated FA (PUFA) content (18.7%). In the rest of the species, PUFAs dominated (>35%). The ratios of major PUFAs varied among the four species studied but all holothurians species were rich in phytoplankton derived FA suggesting tight trophic coupling to phytodetritus. However, for Psolidium sp., bacteria could constitute a substantial portion in the diet. The high level of 20:4n-6 might indicate a significant contribution of protozoans to the diet of Pannychia henrici. Paelopatides sp. and Scotoplanes kurilensis were characterized by a high level of 20:5n-3 and a high value of the 20:5n-3/20:4n-6 ratio, which indicates the predominance of fresh phytodetritus in their diet. The high level of primary production in the upper layers of the Bering Sea provides the high quality of the sedimentary OM and food supply of deposit feeders even at the greatest depths.
•Trophic markers such as stable isotopes and fatty acids can indicate the main food source of deep-sea holothurians inhabiting the Volcanologists Massif.•Fatty acid composition can reflect the specific living environment of deep-sea holothurians along the bathymetric gradient on the Volcanologists Massif.•Observed differences in the biomarkers between the species under study are caused by their food selectivity.•The δ13С values in tissues of all four species indicate the use of organic matter of photosynthetic origin.
Microalgae have great potential as a future source to meet the increasing global demand for foods. Several microalgae are permitted as safety sources in different countries and regions, and processed ...as commercial products. However, edible safety, economic feasibility, and acceptable taste are the main challenges for microalgal application in the food industry. Overcome such challenges by developing technology accelerates transition of microalgae into sustainable and nutritious diets. In this review, edible safety of Spirulina, Chlamydomonas reinhardtii, Chlorella, Haematococcus pluvialis, Dunaliella salina, Schizochytrium and Nannochloropsis is introduced, and health benefits of microalgae-derived carotenoids, amino acids, and fatty acids are discussed. Technologies of adaptive laboratory evolution, kinetic model, bioreactor design and genetic engineering are proposed to improve the organoleptic traits and economic feasibility of microalgae. Then, current technologies of decoloration and de-fishy are summarized to provide options for processing. Novel technologies of extrusion cooking, delivery systems, and 3D bioprinting are suggested to improve food quality. The production costs, biomass values, and markets of microalgal products are analyzed to reveal the economic feasibility of microalgal production. Finally, challenges and future perspectives are proposed. Social acceptance is the major limitation of microalgae-derived foods, and further efforts are required toward the improvement of processing technology.
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