Tropical Food Research Articles

English

This review investigated African yam beans (AYB) as a novel tropical food plant for human nutrition. AYB plants food potentials, its nutritional and amino acid compositions were also examined. In the same vein, the health benefits, utilization of AYB in starch and composite flour technology as well as its toxicological analysis were explored. Also, strategies to minimize processing difficulties and antinutritional factors were highlighted. It was revealed that AYB plant products are very rich in protein, minerals and antioxidants with low glycemic index (GI). Furthermore, viable processing techniques like fermentation, boiling and roasting can reduce AYB antinutritional factors and its toxicological effects. The result suggests that AYB plant products can meet dietary needs of people suffering from malnutrition, kwashiorkor, diabetes and other cardiovascular diseases, thus improving food security. Full utilization of AYB plants in food, drugs and health industries should be explored by carrying out further studies on ethno-pharmacological claims of AYB leaves and tubers. The findings revealed that AYB plant products hold great potential in improving food security globally.   Key words: African yam beans, food security, nutritional factors, health benefits, limiting factors.

Circadian activity patterns of mammalian predators and prey in Costa Rica.

Temporal niche shifts can shape predator–prey interactions by enabling predator avoidance, enhancing feeding success, and reducing competition among predators. Using a community-based conservation approach, we investigated temporal niche partitioning of mammalian predators and prey across 12 long-term camera trap surveys in the Pacific slope and Talamanca Cordillera of Costa Rica. Temporal overlap and segregation were investigated between predator–prey and predator–predator pairs using overlap analysis, circular statistics, and relative abundance after accounting for differences in habitat, season, and human impact among sites. We made the assumption that predators select abundant prey and adjust their activity to maximize their temporal overlap, thus we predicted that abundant prey with high overlap would be preferred prey species for that predator. We also predicted that similar-sized pairs of predator species with the greatest potential for competitive interactions would have the highest temporal segregation. Our results supported the existence of temporal niche separation among the eight species of predators—the smaller Leopardus felids (ocelot, margay, oncilla) were primarily nocturnal, the largest felids (jaguar and puma) and coyote were cathemeral, and the smaller jaguarundi and tayra were mostly diurnal. Most prey species (67%) were primarily nocturnal versus diurnal or cathemeral (33%). Hierarchical clustering identified relationships among species with the most similar activity patterns. We discuss the primary prey and competitor species predicted for each of the eight predators. Contrary to our prediction, the activity pattern of similar-sized intraguild competitors overlapped more than dissimilar-sized competitors, suggesting that similar-sized predators are hunting the same prey at the same time. From this we conclude that prey availability is more important than competition in determining circadian activity patterns of Neotropical predators. Our results indicate the presence of a delicate balance of tropical food webs that may be disrupted by overhunting, leading to a depauperate community consisting of ubiquitous generalists and endangered specialists. With Central America a hotspot for hunting-induced “empty forests,” community-based conservation approaches may offer the best road to reduce illegal hunting and maintain the biodiversity and community structure of tropical forest systems.

Bioaccumulation of Per- and polyfluoroalkyl substances (PFASs) in a tropical estuarine food web

The biomagnification of per- and polyfluoroalkyl substances (PFASs) was investigated in a tropical mangrove food web from an estuary in Bahia, Brazil. Samples of 44 organisms (21 taxa), along with biofilm, leaves, sediment and suspended particulate matter were analyzed. Sum (∑) PFAS concentrations in biota samples were dominated by perfluorooctane sulfonate (PFOS, 93% detection frequency in tissues; 0.05 to 1.97 ng g−1 ww whole-body (wb)), followed by perfluorotridecanoate (PFTrDA, 57%; 0.01 to 0.28 ng g−1 ww wb). PFOS precursors such as perfluorooctane sulfonamide (FOSA, 54%; 0.01 to 0.32 ng g−1 ww wb) and N-ethyl perfluorooctane sulfonamide (EtFOSA; 30%; 0.01 to 0.21 ng g−1 ww wb) were also detected. PFAS accumulation profiles revealed different routes of exposure among bivalve, crustacean and fish groups. Statistics for left-censored data were used in order to minimize bias on trophic magnification factors (TMFs) calculations. TMFs >1 were observed for PFOS (linear + branched isomers), EtFOSA (linear + branched isomers), and perfluorononanoate (PFNA), and in all cases, dissimilar accumulation patterns were observed among different trophic positions. The apparent biodilution of some long-chain PFCAs through the food chain (TMF < 1) may be due to exposure from multiple PFAS sources. This is the first study investigating bioaccumulation of PFASs in a tropical food web and provides new insight on the behavior of this ubiquitous class of contaminants.

Horizontal Integration with Emphasize on IoT: from Tropical Functional Food Research to Teaching Excellence

The laboratory is a research powerhouse being a transportation membrane to propagate new and proven knowledge. This paper aims to descriptively disseminate the concept of horizontal integration from research in tropical functional food resources to teaching excellence framework with an emphasize on IoT Technology. The five-stage framework includes (1) vision internalization, (2) persistence propagation, (3) new technology adaptation, (4) extending collaboration, and (5) outcome integration. The vision internalization stage produces a better understanding of the big picture and systematic approach required, including the division of experiments to research attendance. The experience is then brought to Research Methodology and Research Design classes. In the second stage, persistence propagation may be better translated to relentlessly solving the problem and to increase the laboratory power. The persistence propagation also includes providing fail-safe and verification procedures of possibly dubious results produced in the laboratory. In the end, it may improve operating procedures or methods in a laboratory manual. The movement of open hardware makes it possible for faster technology adaptation to food-laboratory. For example, measuring functional food material drying kinetics is now quickly adopted as a result of recent IoT technology. In a later stage, IoT is integrated into the closest courses, i.e., Introduction to Computer or Programming in Food Technology. The research may reach a milestone that requires expansion and sophisticated equipment beyond the capacity of the laboratory. Therefore, collaboration is needed between laboratories within the university or greater. Students are prepared to conduct functional food research in partner laboratories; hence, the requisite bench skills are better taught. The last stage happens when new and related knowledge is accumulated, i.e., umbrella research in functional food produces several publications and theses. Researchers may visit and align the current curriculum in the subject of Functional Food Technology. In summary, the horizontal integration with an emphasize on IoT Technology results in a unique set of research-teaching excellence framework that is incrementally developed.

Bioaccumulation and trophic transfer of organophosphate esters in tropical marine food web, South China Sea

Environmental exposure to organophosphate esters (OPEs) continues to be a concern. Little is known about their bioaccumulation and trophodynamics, especially in tropical food webs. This study collected seawater and fifteen types of organism from a tropical ecosystem, South China Sea, to investigate the species-specific compositional, bioaccumulation, and trophic transfer of OPEs. The total concentrations of 11 target OPEs (ng/g dw) in the organisms decreased with the increase of their trophic levels in the order: phytoplankton (922) > zooplankton (660) > oysters (309) > crabs (225) > coral tissues (202) > fishes (58.2). The composition profiles (relative abundances) of OPEs were different among the species of organisms, which is likely affected by metabolism and the physicochemical property of OPEs. The trophic biomagnification of tripentyl phosphate (TPTP) in the pelagic food web was unexpected and requires further investigation. The trophic magnification factors (TMFs) of OPEs were generally lower in this tropical aquatic food web than in temperate and frigid aquatic food web. Our analysis suggests that there is a significant positive linear correlation between latitude and TMF. Intakes of OPEs through the consumption of the seafood involved in this work does not pose health risk to adults.

Development of Commercial Tapioca Pearls used in Bubble Tea by Microwave Heat–Moisture Treatment in Cassava Starch Modification

Bubble tea is a trending food product around the globe and capture a high demand in the high-end market in Asian region as well. This product contains a chewy bubble in enhancing the palatability and the acceptability of the final bubble tea product, which is made with cassava starch. Cassava is an important high caloric tropical food crop, yet has a limited utilization due to its perishability and high cyanide content. Industrial processing of cassava into several food products is one of the most preferred solution for this and thus, tapioca pearl production is also one of the major food application of cassava starch. So the main objective of this study to develop a standardized and much preferred method of tapioca pearl production, and develop a tapioca pearl to be incorporated in bubble tea with higher sensory acceptance, and lower cost. A standard procedure was developed after several trials, and considering the economic benefit, cassava flour incorporated pearls were also tried. The made pearls were subjected to sensory evaluation, proximate composition and cyanide content analysis, as well as texture profile analysis, and finally, the microbiological stability of the product was also checked under refrigerated storage conditions. According to the obtained results, the final product was sensory accepted (p&lt;0.05) over the commercially available product and had a laboratory proven shelf life of 30 days under refrigerated storage conditions.

Development of Commercial Tapioca Pearls used in Bubble Tea by Microwave Heat–Moisture Treatment in Cassava Starch Modification

Bubble tea is a trending food product around the globe and capture a high demand in the high-end market in Asian region as well. This product contains a chewy bubble in enhancing the palatability and the acceptability of the final bubble tea product, which is made with cassava starch. Cassava is an important high caloric tropical food crop, yet has a limited utilization due to its perishability and high cyanide content. Industrial processing of cassava into several food products is one of the most preferred solution for this and thus, tapioca pearl production is also one of the major food application of cassava starch. So the main objective of this study to develop a standardized and much preferred method of tapioca pearl production, and develop a tapioca pearl to be incorporated in bubble tea with higher sensory acceptance, and lower cost. A standard procedure was developed after several trials, and considering the economic benefit, cassava flour incorporated pearls were also tried. The made pearls were subjected to sensory evaluation, proximate composition and cyanide content analysis, as well as texture profile analysis, and finally, the microbiological stability of the product was also checked under refrigerated storage conditions. According to the obtained results, the final product was sensory accepted (p&lt;0.05) over the commercially available product and had a laboratory proven shelf life of 30 days under refrigerated storage conditions.

Reaction of rice bean [Vigna umbellata (Thunb.) Ohwi and Ohashi] landraces from Manipur to bruchid infestation

Rice bean (Vigna umbellata) is one of the under-exploited tropical food legumes and is regarded as a potentially valuable multipurpose (grain, fodder and green manure) crop for farmers in the marginal hill areas of north-eastern India, especially Manipur. The seeds of rice bean are comparatively resistant to storage grain pests including bruchids (Callosobruchus maculatus), which generally damage other pulses. However, there are reports of seed damage by bruchids during storage. In the present study, seeds of seven rice bean landraces collected from local markets in Imphal, Manipur and one landrace from the Himalayan region (later maintained at Agricultural Research Station, Virinjipuram, Vellore, Tamil Nadu) were used to determine their reaction against bruchid infestation. The results suggested no role of antixenosis (non-preference) mechanism in imparting resistance to bruchids. Understanding of factor(s) contributing to bruchid resistance is useful for development of rice bean cultivars. To date, rice bean has not been subjected to systematic breeding, despite the species' many useful characteristics. The results of the study will be particularly useful in identifying genotypes for use as parents in pulse breeding programmes.

Predation risk is a function of alternative prey availability rather than predator abundance in a tropical savanna woodland ecosystem

Typically, factors influencing predation risk are viewed only from the perspective of predators or prey populations but few studies have examined predation risk in the context of a food web. We tested two competing hypotheses regarding predation: (1) predation risk is dependent on predator density; and (2) predation risk is dependent on the availability of alternative prey sources. We use an empirical, multi-level, tropical food web (birds–lizards–invertebrates) and a mensurative experiment (seasonal fluctuations in abundance and artificial lizards to estimate predation risk) to test these hypotheses. Birds were responsible for the majority of attacks on artificial lizards and were more abundant in the wet season. Artificial lizards were attacked more frequently in the dry than the wet season despite a greater abundance of birds in the wet season. Lizard and invertebrate (alternative prey) abundances showed opposing trends; lizards were more abundant in the dry while invertebrates were more abundant in the wet season. Predatory birds attacked fewer lizards when invertebrate prey abundance was highest, and switched to lizard prey when invertebrate abundance reduced, and lizard abundance was greatest. Our study suggests predation risk is not predator density-dependent, but rather dependent on the abundance of invertebrate prey, supporting the alternative prey hypothesis.

Climate change effects on Black Sigatoka disease of banana

Climate change has significantly altered species distributions in the wild and has the potential to affect the interactions between pests and diseases and their human, animal and plant hosts. While several studies have projected changes in disease distributions in the future, responses to historical climate change are poorly understood. Such analyses are required to dissect the relative contributions of climate change, host availability and dispersal to the emergence of pests and diseases. Here, we model the influence of climate change on the most damaging disease of a major tropical food plant, Black Sigatoka disease of banana. Black Sigatoka emerged from Asia in the late twentieth Century and has recently completed its invasion of Latin American and Caribbean banana-growing areas. We parametrize an infection model with published experimental data and drive the model with hourly microclimate data from a global climate reanalysis dataset. We define infection risk as the sum of the number of modelled hourly spore cohorts that infect a leaf over a time interval. The model shows that infection risk has increased by a median of 44.2% across banana-growing areas of Latin America and the Caribbean since the 1960s, due to increasing canopy wetness and improving temperature conditions for the pathogen. Thus, while increasing banana production and global trade have probably facilitated Black Sigatoka establishment and spread, climate change has made the region increasingly conducive for plant infection.This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’. This issue is linked with the subsequent theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’.

Toxic Algae Silence Physiological Responses to Multiple Climate Drivers in a Tropical Marine Food Chain.

Research on the effects of climate change in the marine environment continues to accelerate, yet we know little about the effects of multiple climate drivers in more complex, ecologically relevant settings – especially in sub-tropical and tropical systems. In marine ecosystems, climate change (warming and freshening from land run-off) will increase water column stratification which is favorable for toxin producing dinoflagellates. This can increase the prevalence of toxic microalgal species, leading to bioaccumulation of toxins by filter feeders, such as bivalves, with resultant negative impacts on physiological performance. In this study we manipulated multiple climate drivers (warming, freshening, and acidification), and the availability of toxic microalgae, to determine their impact on the physiological health, and toxin load of the tropical filter-feeding clam, Meretrix meretrix. Using a structural equation modeling (SEM) approach, we found that exposure to projected marine climates resulted in direct negative effects on metabolic and immunological function and, that these effects were often more pronounced in clams exposed to multiple, rather than single climate drivers. Furthermore, our study showed that these physiological responses were modified by indirect effects mediated through the food chain. Specifically, we found that when bivalves were fed with a toxin-producing dinoflagellate (Alexandrium minutum) the physiological responses, and toxin load changed differently and in a non-predictable way compared to clams exposed to projected marine climates only. Specifically, oxygen consumption data revealed that these clams did not respond physiologically to climate warming or the combined effects of warming, freshening and acidification. Our results highlight the importance of quantifying both direct and, indirect food chain effects of climate drivers on a key tropical food species, and have important implications for shellfish production and food safety in tropical regions.

Terpene-Rich Medicinal Plant Spices for Flavoring of Processed Tropical Food

Tropical medicinal plant spices have remained underutilized in commercial food processing because of the inadequate chemical characterization of their terpene compositions. The activity of medicinal plants used in flavoring is due to their terpene contents. Terpene contents of Aframomum danielli seeds, Xylopia aethiopica fruits, Syzygium aromaticum leaves, Piper guineense seeds, and Monodora myristica seeds were determined using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry. P. guineense is rich in terpinene and terpinolene (2.5 g per 100 g), S. aromaticum has caryophyllene (0.68 g per 100 g); A. danielli is rich in ocimene (1.65 g per 100 g); X. aethiopica is rich in ocimene (2.94 g per 100 g); M. mystristica is rich in delta carene (0.49 g per 100 g). Combinations of the five medicinal plant spices are being applied as flavorings in packaged tropical food.

Legal Implications on Mismanagement of Agrochemicals in Smallholders' Agro Production in Malaysia

Purpose of this study is attempted to look into laws on mismanagement of agrochemicals towards the agro food production and conservation of ecosystem in Malaysia. Artificial fertilizers, fungicides, herbicides and insecticides in manageable of rural farmers' food yielding production could cost human hardship upon consumptions and detrimental to conservation. Economic sustainable minimal or chemical free tropical food yielding agriculture food crop not only will reap in profits in upgrading income and livelihood but will definitely create a good environment in developing countries. There are significant differences on laws on the issue of mismanagement of agrochemical application towards the production and conservation of ecosystems in Malaysia with the implementation of laws on agriculture chemicals.

What happens when thermally vulnerable species are removed from food web networks?

Event Abstract Back to Event What happens when thermally vulnerable species are removed from food web networks? Catarina Vinagre1*, Vanessa Mendonça1, Carolina Madeira1, Marta Dias1, Ana Silva2 and Augusto A. Flores3 1 Universidade de Lisboa, MARE – Marine and Environmental Sciences Centre, Faculdade de Ciências, Campo Grande, 1749-016 Lisboa, Portugal , Portugal 2 Instituto Superior Técnico, Universidade de Lisboa, CERIS, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais 1, 1049-001-Lisboa, Portugal, Portugal 3 Universidade de São Paulo, Centro de Biologia Marinha, Universidade de São Paulo, Rod. Manoel Hipólito do Rego, km 131.5, São Sebastião, SP, Brazil, Brazil Intertidal rock pool environments harbor particularly high biodiversity and constitute important refuges for early stages of many marine organisms. These environments have little thermal inertia and can attain temperatures that are higher than the maximum critical temperatures (CTMax) of some of its’ species. In this study tropical and temperate rock pools were used as mesocosms to understand what happens to the network structure of food webs when thermally vulnerable species are removed. Highly defined food web networks were assembled for rock pools in Brazil and in Portugal, where the CTMax of its more common species was already tested. Species were sequentially removed from the food web based on their thermal vulnerability. Structural robustness was defined as the fraction of species that had to be removed in order to result in the loss of ≥50% of the species in the original web (i.e. primary species removals plus secondary extinctions). Tropical and temperate food webs revealed similar robustness, however tropical food webs presented alterations in more food web properties. Acknowledgements Thanks are due to the institutions and staff that hosted this work: CEBIMAR-USP and Instituto Oceanográfico-USP. This study had the support of the Portuguese Foundation for Science and Technology through the WarmingWebs project, PTDC/MAR-EST/2141/2012, the “Investigador FCT” position granted to C. Vinagre and the strategic project UID/MAR/04292/2013 granted to MARE. The authors are grateful to Jennifer Dunne (Santa Fe Institute) for guidance in the initial steps of this idea. Keywords: Food Web Dynamics, Network analysis, Climate Change, Rocky intertidal, predator-prey interactions Conference: IMMR'18 | International Meeting on Marine Research 2018, Peniche, Portugal, 5 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Biodiversity, Conservation and Coastal Management Citation: Vinagre C, Mendonça V, Madeira C, Dias M, Silva A and Flores AA (2019). What happens when thermally vulnerable species are removed from food web networks?. Front. Mar. Sci. Conference Abstract: IMMR'18 | International Meeting on Marine Research 2018. doi: 10.3389/conf.FMARS.2018.06.00042 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 24 Apr 2018; Published Online: 07 Jan 2019. * Correspondence: Dr. Catarina Vinagre, Universidade de Lisboa, MARE – Marine and Environmental Sciences Centre, Faculdade de Ciências, Campo Grande, 1749-016 Lisboa, Portugal, Lisbon, Portugal, cmvinagre@ualg.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Catarina Vinagre Vanessa Mendonça Carolina Madeira Marta Dias Ana Silva Augusto A Flores Google Catarina Vinagre Vanessa Mendonça Carolina Madeira Marta Dias Ana Silva Augusto A Flores Google Scholar Catarina Vinagre Vanessa Mendonça Carolina Madeira Marta Dias Ana Silva Augusto A Flores PubMed Catarina Vinagre Vanessa Mendonça Carolina Madeira Marta Dias Ana Silva Augusto A Flores Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

How Functional Is Moringa oleifera? A Review of Its Nutritive, Medicinal, and Socioeconomic Potential.

Moringa oleifera is an important tropical food plant that seems to have great nutritional, therapeutic, industrial, agricultural, and socioeconomic value. Dietary consumption of its parts and preparations is encouraged by several organizations, health food enthusiasts, and other specialists as a strategy of personal health preservation and self-medication in the treatment of various diseases. Studies extoling its ability to mitigate various degenerative ailments now exist in both the scientific and the popular literature. At face value, and considering the volume of reports available, much of this enthusiasm seems to be indeed justified. However, it is imperative to distinguish rigorous scientific evidence from anecdote. To achieve this, relevant experimental and review articles were sought and read critically to identify recent patterns and trends on this subject matter. Studies on the medicinal and functional properties of M. oleifera are available from various parts of the world, especially developing regions. Attempts have been made to parse the contemporary scientific data available supporting the claims regarding the phytochemical, nutritive, medicinal, environmental, agricultural, and socioeconomic capabilities of this plant. Studies reviewed provide compelling, albeit preliminary experimental evidence of therapeutic potential of the plant. It is important that M. oleifera products and preparations be properly chemically characterized and standardized before being administered.

Baquianos Still Life. The "Espejo de Paciencia" and the Doramas's Forest

The offering of tropical food and flowers by pagan deities, toward the end of the First Canto of Espejo de paciencia (1608), is undoubtedly the most talked episode of Silvestre de Balboa’s (1563-c.1647) epic poem. We assume the most recent reviews (Firbas, Gonzalez Echevarria, Marrero-Fente), advocating an alternative to the idea of a Cuban primitive , dominant in the comments about this poem, since its discovery in 1836, and during most of the twentieth century (Pichardo, Vitier, Lezama). And we propose an analysis of the issue of indigenous nature from two dimensions: against the background of the interests of the colonial society on the one hand; and as a poetic system that has the marks of digression and periphera, on the other one. For the first dimension, we rely on the work of historian Garcia del Pino; for the second, in the structure of the myth of Doramas Forest, of Cairasco (1538-1610), because of its relevance in literary and Balboa training for his native still life settings.

Edible insects: marketing the impossible?

Is it an impossible task to convince consumers to eat insects? This does not only apply to western consumers who are less familiar with this food habit than consumers in tropical countries. In the tropics too, many people do not consume insects, even though they are easier to collect as food than in temperate zones. Until recently in the western world, eating insects was considered a peculiar tropical food habit and the term 'entomophagy' was coined. How to motivate consumers to substitute meat with insects? One strategy is to stress the low environmental impact of insect products compared to meat, in particular beef. Or is this, considering our appetite for meat, an inconvenient truth? Is stressing environmental sustainability enough to raise consumers' interest to consume insects? Probably not, as tastiness is valued high and crucial. However, even a positive sensory experience when consuming insects should be accompanied by external factors such as availability, convenient pricing and a conducive social environment.

Solar dryers for tropical food preservation: Thermophysics of crops, systems and components

Drying reduces the moisture content of harvested crops thus slowing decay processes to enable longer-term storage. Solar dryers contain the crop being dried, to enhance solar energy collection incurring lower crop losses than are associated with open-sun drying and recurrent costs than are inherent to uses of fossil-fuels for drying. The influences of key environmental, operational and design parameters for solar dryers are discussed including: (i) psychrometry of drying processes and ambient conditions, (ii) how initial crop properties are converted to final desired product attributes, (iii) feasibility of using powered components such as fans and (iv) air-heating solar collector selection.

New Perspectives of Quantum Dots in the Food Field: Determination of β-Carotene in Tropical Fruit Juices and Food Supplements

A novel and simple method for the determination of β-carotene, a carotenoid abundant in plants and fruits, is proposed. Multicommutated flow injection analysis (MCFIA) has been applied as automated flow methodology to the analysis of β-carotene in tropical fruit juices and food supplements, making use of the quenching effect caused by this analyte over glutathione-capped CdTe quantum dots (QDs) fluorescence signal. Under optimized conditions, the method was linear in the range of 0.3–15 μg mL−1, with a detection limit of 0.09 μg mL−1 and relative standard deviations lower than 3%. The determination rate was of about 80 h−1, and results were in good agreement with those provided by both the manufacturer and a chromatographic reference method.

Resistance determination of a South Indian bruchid strain against rice bean landraces of Manipur (India)

Rice bean (Vigna umbellata) is one of the under-exploited tropical food legumes. It is regarded as a potentially valuable multipurpose (grain, fodder and green manure) crop among farmers in the marginal hill areas of North-Eastern India, Manipur in particular. Rice bean seeds are comparatively resistant to storage grain pests including bruchids (Callosobruchus spp.), which generally damages other pulses of the same genus Vigna and related legumes. However, there are reports of seed infestation by bruchids during storage. The present investigation involved subjecting seeds of rice bean landraces from Manipur to low and high bruchid infestation levels in order to determine their reaction. This is the first report on bruchid bioassay conducted on landraces of this remotely situated Indian state. The landraces were classified based on the seed damage per cent with 1–9 score. Although variations in oviposition response were observed among the landraces, regression and correlation studies between seed characteristics and bruchid life parameters suggested no significant role of antixenosis (non-preference) mechanism in imparting resistance to bruchids. To date, rice bean has not been subjected to systematic breeding, despite the species' many useful characteristics. The experiments revealed identification of new sources of bruchid resistance. Hence, these landraces can be effectively used as promising donors for hybridization in pulse improvement programmes.