1000 resultados para Food writers
Resumo:
Patulin is a mycotoxin produced by several fungal species of the genera Penicillium and Aspergillus, found on several fruit species and, remarkably, in apples and apple products. Patulin has a broad spectrum of toxicity, including carcinogenicity and teratogenicity in animals. Due to the stability of the molecule, considerable amounts of patulin still remain in apple products after processing. This paper reviews different analytical methods for patulin determination and methods to reduce levels of patulin in apple products as well.
Resumo:
The global human population is expected to reach ∼9 billion by 2050. Feeding this many people represents a major challenge requiring global crop yield increases of up to 100%. Microbial symbionts of plants such as arbuscular mycorrhizal fungi (AMF) represent a huge, but unrealized resource for improving yields of globally important crops, especially in the tropics. We argue that the application of AMF in agriculture is too simplistic and ignores basic ecological principals. To achieve this challenge, a community and population ecology approach can contribute greatly. First, ecologists could significantly improve our understanding of the determinants of the survival of introduced AMF, the role of adaptability and intraspecific diversity of AMF and whether inoculation has a direct or indirect effect on plant production. Second, we call for extensive metagenomics as well as population genomics studies that are crucial to assess the environmental impact that introduction of non-local AMF may have on native AMF communities and populations. Finally, we plead for an ecologically sound use of AMF in efforts to increase food security at a global scale in a sustainable manner.
Resumo:
Environmental histories of plant exchanges have largely centred on their eco- nomic importance in international trade and on their ecological and social impacts in the places where they were introduced. Yet few studies have at- tempted to examine how plants brought from elsewhere become incorporated over time into the regional cultures of material life and agricultural landscapes. This essay considers the theoretical and methodological problems in inves- tigating the environmental history, diversity and distribution of food plants transferred across the Indian Ocean over several millennia. It brings together concepts of creolisation, syncretism, and hybridity to outline a framework for understanding how biotic exchanges and diffusions have been translated into regional landscape histories through food traditions, ritual practices and articu- lation of cultural identity. We use the banana plant - which underwent early domestication across New Guinea, South-east Asia and peninsular India and reached East Africa roughly two thousand years ago - as an example for il- lustrating the diverse patterns of incorporation into the cultural symbolism, material life and regional landscapes of the Indian Ocean World. We show that this cultural evolutionary approach allows new historical insights to emerge and enriches ongoing debates regarding the antiquity of the plant's diffusion from South-east Asia to Africa.
Resumo:
Understanding how best to support immature writers in the development of their understanding of the writing process is an important concern for researchers and teachers. Social technologies have become key features of leisure and work place writing, yet knowledge about how to design educational settings that take full advantage of the affordances of web 2.0 technologies to support early writing is scarce. This paper presents a small scale study that investigated how writing in a wiki environment might facilitate and support students’ use of composition and revision strategies. Our findings show that wiki can enlarge young writers’ experience of the process of composition and revision both through their own efforts and by observing the process in others. In this study students employed a wide range of types of revisions both surface and text based changes. These revisions took place during the process of composition as well as at the end. It is argued here that writing in a wiki not only provides young writers with experience of a mode of composition prevalent in the contemporary work environment, but breaks up the process of writing in a way that may support students’ understanding of the processes of composition and revision.
Resumo:
Micronization techniques based on supercritical fluids (SCFs) are promising for the production of particles with controlled size and distribution. The interest of the pharmaceutical field in the development of SCF techniques is increasing due to the need for clean processes, reduced consumption of energy, and to their several possible applications. The food field is still far from the application of SCF micronization techniques, but there is increasing interest mainly for the processing of products with high added value. The aim of this study is to use SCF micronization techniques for the production of particles of pharmaceuticals and food ingredients with controlled particle size and morphology, and to look at their production on semi-industrial scale. The results obtained are also used to understand the processes from the perspective of broader application within the pharmaceutical and food industries. Certain pharmaceuticals, a biopolymer and a food ingredient have been tested using supercritical antisolvent micronization (SAS) or supercritical assisted atomization (SAA) techniques. The reproducibility of the SAS technique has been studied using physically different apparatuses and on both laboratory and semi-industrial scale. Moreover, a comparison between semi-continuous and batch mode has been performed. The behaviour of the system during the SAS process has been observed using a windowed precipitation vessel. The micronized powders have been characterized by particle size and distribution, morphology and crystallinity. Several analyses have been performed to verify if the SCF process modified the structure of the compound or caused degradation or contamination of the product. The different powder morphologies obtained have been linked to the position of the process operating point with respect to the vapour-liquid equilibrium (VLE) of the systems studied, that is, mainly to the position of the mixture critical point (MCP) of the mixture. Spherical micro, submicro- and nanoparticles, expanded microparticles (balloons) and crystals were obtained by SAS. The obtained particles were amorphous or with different degrees of crystallinity and, in some cases, had different pseudo-polymorphic or polymorphic forms. A compound that could not be processed using SAS was micronized by SAA, and amorphous particles were obtained, stable in vials at room temperature. The SCF micronization techniques studied proved to be effective and versatile for the production of particles for several uses. Furthermore, the findings of this study and the acquired knowledge of the proposed processes can allow a more conscious application of SCF techniques to obtain products with the desired characteristics and enable the use of their principles for broader applications.
Resumo:
The present study arose from the need to determine inorganic arsenic (iAs) at low levels in cereal-based food. Validated methods with a low limit of detection (LOD) are required to analyse these kinds of food. An analytical method for the determination of iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA) in cereal-based food and infant cereals is reported. The method was optimised and validated to achieve low LODs. Ion chromatography-inductively coupled plasma mass spectrometry (LC-ICPMS) was used for arsenic speciation. The main quality parameters were established. To expand the applicability of the method, different cereal products were analysed: bread, biscuits, breakfast cereals, wheat flour, corn snacks, pasta and infant cereals. The total and inorganic arsenic content of 29 cereal-based food samples ranged between 3.7-35.6 and 3.1-26.0 microg As kg-1, respectively. The present method could be considered a valuable tool for assessing inorganic arsenic contents in cereal-based foods.
Resumo:
Suojakaasupakkaaminen on lisääntynyt voimakkaasti viime vuosina elintarvikkeiden pakkaamisessa sillä pakkaamalla elintarvike suojakaasuun voidaan sen hyllyikää pidentää ilman säilöntäaineita. Tällainen pakkaaminen vaatii kuitenkin täysin kaasutiiviin pakkauksen, jonka kaasunläpäisevyys on myös alhainen. Yleisimmin käytetyt pakkausmateriaalit suojakaasupakkaamisessa ovat monikerroksiset muovimateriaalit, joissa yhdistyy monen eri muovin parhaimmat ominaisuudet. Yleisimmin käytettyjä muovilaatuja näissä monikerrosrakenteissa ovat PE, PET, PA ja EVOH polymeerit. Myös muita perinteisiä polymeerejä käytetään jonkin verran näissä rakenteissa. Uudemmat muovilaadut, kuten biohajoavat muovit, eivät ole vielä yleistyneet kaupallisessa käytössä pääasiallisesti niiden korkean hinnan vuoksi. Muovisten pakkausten korvaamista esimerkiksi muovipäällystetyillä kartonkipakkauksilla on viime vuosien aikana tutkittu enenevissä määrin. Muovipakkausten korvaamista helpommin kierrätettävillä ja mahdollisesti biohajoavilla materiaaleilla edistävät EU:n direktiivit, jotka käsittelevät pakkausjätteen käsittelyä. Kartonkivuokien saumaamista kaasutiiviisti tutkittiin myös tässä työssä. Tavoitteena oli löytää pakkaus, joka soveltuisi kanasuikaleiden pakkaamiseen suojakaasuun. Kana on herkkä mikrobiologiselle hajoamiselle, minkä johdosta se tulee pakata suojakaasuun jossa happipitoisuuden tulee olla alle 1 % pakkauspäivästä viimeiseen käyttöpäivään saakka. Suorittamalla erilaisia tiiveystutkimuksia voitiin osoittaa, että kartonkivuoka on mahdollista saumata kaasutiiviisti luotettavalla tavalla. Tämä vaatii kuitenkin kartonkivuokien valmistuksen optimoimista päällystemuovikerroksen ja kartongin paksuuden mukaan sekä kannen saumaamista optimoiduilla saumausparametreilla. Tiivein vuoka saavutettiin muovifilmikannella, jonka saumaus perustui samaan muoviin kuin vuoan saumaus. Polyeteenillä saavutettiin tiivein ja kestävin saumaustulos.
Resumo:
The effect of different food matrices on the metabolism and excretion of polyphenols is uncertain. The objective of the study was to evaluate the possible effect of milk on the excretion of (2)-epicatechin metabolites from cocoa powder after its ingestion with and without milk. Twenty-one volunteers received the following three test meals each in a randomised cross-over design with a 1-week interval between meals: (1) 250 ml whole milk as a control; (2) 40 g cocoa powder dissolved in 250 ml whole milk (CC-M); (3) 40 g cocoa powder dissolved in 250 ml water (CC-W). Urine was collected before consumption and during the 0-6, 6-12 and 12-24 h periods after consumption. (2)-Epicatechin metabolite excretion was measured using liquid chromatography-MS. One (2)-epicatechin glucuronide and three (2)-epicatechin sulfates were detected in urine excreted after the intake of the two cocoa beverages (CC-M and CC-W). The results show that milk does not significantly affect the total amount of metabolites excreted in urine. However, differences in metabolite excretion profiles were observed; there were changes in the glucuronide and sulfate excretion rates, and the sulfation position between the period of excretion and the matrix. The matrix in which polyphenols are consumed can affect their metabolism and excretion, and this may affect their biological activity. Thus, more studies are needed to evaluate the effect of these different metabolite profiles on the body.
Resumo:
Harmonia axyridis was detected for the first time in Brazil in 2002. Since then, it has been recorded from the South to the Midwest of the country. Until now, almost all the registered cases were associated with the presence of aphids, its preferred source of food. Due to the occurrence of this species in areas of fruit growing in the South and Southeast of Brazil, the aim of this study was to analyze the preference and use of three different cultivars of fruit. The tests were set at 25ºC ± 1ºC, RH 70% ± 10%, and in a photophase of 12 h and with apples (Gala and Fuji), grapes (Niágara and Rubi), and pears (Williams and Asian). In the undamaged fruit experiment, the insects did not cause any noticeable damage. In the damaged and undamaged fruit experiment, a higher and statistically significant percentage of H. axyridis adults were found in the three damaged fruits. In the different cultivar experiment the Niágara grape, the Gala apple, and the Williams pear were significantly preferred by H. axyridis adults. These results may help in the management of this insect, preventing damage, which have been observed in other places where H. axyridis was introduced.
Resumo:
Previous research has shown that different foods are stereotypically associated with gender and that eating in a role-congruent way fulfills an impression management function. On the other hand, other studies revealed that adapting one's food consumption to that of the co-eaters is a means to gain social approval as well. In the present study, we bridge these two distinct lines of research by studying what happens when the two norms (conforming to the gender-based stereotype and imitating the co-eater) conflict, that is with opposite-sex co-eaters. Results indicated that the tendency to match the co-eaters' supposed consumption generally appeared over and above one's gender-congruent choice. In addition, as expected, gender differences also emerged: while men were always willing to adapt to the co-eaters, women's intention to eat the feminine food was independent from the co-eaters' gender.
Resumo:
Sparus aurata larvae reared under controlled water-temperature conditions during the first 24 days after hatching displayed a linear relationship between age (t) and standard length (SL): SL = 2.68 + 0.19 t (r2 = 0.91l). Increments were laid down in the sagittae with daily periodicity starting on day of hatching. Standard length (SL) and sagittae radius (OR) were correlated: SL(mm) = 2.65 + 0.012 OR(mm). The series of measurements of daily growth increment widths (DWI), food density and water temperature were analyzed by means of time series analysis. The DWI series were strongly autocorrelated, the growth on any one day was dependent upon growth on the previous day. Time series of water temperatures showed, as expected, a random pattern of variation, while food consumed daily was a function of food consumed the two previous days. The DWI series and the food density were correlated positively at lags 1 and 2. The results provided evidence of the importance of food intake upon the sagittae growth when temperature is optimal (20ºC). Sagittae growth was correlated with growth on the previous day, so this should be taken into account when fish growth is derived from sagittae growth rates.