Caracterização física, química, microbiológica e sensorial de geléias light de abacaxi

O trabalho objetivou elaborar geléias com reduzido teor calórico, utilizando como agentes de corpo diferentes combinações dos hidrocolóides xantana, carragena e locusta. Como comparativo utilizou-se uma formulação padrão de geléia de abacaxi (controle), elaborada com sacarose e xarope de glicose na proporção de 4:1 (p/p), e com teor final de sólidos solúveis de 65ºBrix. As quatro formulações light foram preparadas pela substituição de 50% da quantidade de açúcar da formulação controle, sendo que para equiparar a doçura, adicionou-se o edulcorante sucralose. Foram avaliadas as características químicas, físicas, microbiológicas e sensoriais, além do valor calórico total das geléias. Os resultados mostraram que as geléias apresentaram características químicas e físicas semelhantes às descritas na literatura e enquadraram-se na categoria de produtos light, segundo a legislação vigente. Quanto às características microbiológicas, todas as formulações enquadraram-se nos padrões microbiológicos estabelecidos pela legislação brasileira. Em termos sensoriais a formulação com a combinação das gomas carragena:xantana:locusta (1:1:1, p/p/p) foi a que apresentou melhores características de geléia.

Efeito do uso de cultura adjunta (Lactobacillus helveticus) na proteólise, propriedades viscoelásticas e aceitação sensorial de queijo prato light

A proteólise, as propriedades viscoelásticas e a aceitação sensorial de queijo prato light fabricado com e sem adição de cultura adjunta (CAD) foram avaliadas. Os queijos foram fabricados a partir de leite microfiltrado. Dois tratamentos foram testados em duplicata: o queijo controle foi fabricado apenas com cultura mesófila tradicional (acidificante e aromatizante), e o outro foi fabricado com adição de CAD (Lactobacillus helveticus), além da cultura tradicional. A composição dos queijos foi determinada no quinto dia após a fabricação. A proteólise e as propriedades reológicas foram avaliadas nos dias 5, 25 e 45 após a fabricação. Os parâmetros viscoelásticos foram obtidos a partir de testes de relaxação. As amostras foram avaliadas sensorialmente por meio de testes de aceitação. Não houve diferença significativa (p>0,05) na composição dos queijos. Os índices de profundidade de proteólise foram significativamente (p<0,05) maiores ao final do tempo de maturação para o queijo fabricado com adição de CAD. As propriedades viscoelásticas dos queijos não foram influenciadas pelo uso de CAD (p>0,05). Nos testes de aceitação sensorial, o queijo produzido com CAD obteve notas significativamente (p<0,05) mais altas para os atributos aroma, textura e impressão global. Em relação ao atributo intenção de compra, 70% dos consumidores, certamente ou provavelmente, comprariam o queijo com CAD, enquanto apenas 43,4% teriam a mesma atitude em relação ao queijo controle.

Perfil sensorial de iogurte light, sabor pêssego

Foi determinado o perfil sensorial descritivo de três amostras de iogurte light, sabor pêssego, pela metodologia fundamentada na Análise Descritiva Quantitativa (ADQ). A equipe sensorial definiu os termos descritores, os materiais de referência para o treinamento das qualidades e quantificações de cada um dos termos e a ficha de avaliação das amostras, de forma consensual. Dez provadores foram selecionados e rigorosamente treinados para compor a equipe definitiva, utilizando-se como critérios o poder discriminativo, reprodutibilidade e consenso dos provadores entre si. Foram gerados doze termos descritores pelo método de rede. A intensidade de cada descritor foi avaliada em cada amostra por escala não estruturada de nove centímetros, com termos de intensidade ancorados em seus extremos, sendo o mínimo à esquerda e o máximo à direita. Os dados foram analisados por ANOVA, Teste de Tukey e Análise de Componentes Principais (ACP). Os resultados indicaram que as amostras comerciais apresentaram grande variação em seus perfis sensoriais. Na ACP, ficou evidenciado que a amostra A foi caracterizada principalmente pelos atributos gosto doce, sabor pêssego e firmeza dos pedaços de fruta. A amostra B foi caracterizada pelos atributos brilho, cor pêssego e cremosidade, e a amostra C foi caracterizada pela maior intensidade dos atributos gosto ácido, adstringência, textura farinácea e aroma artificial de pêssego. De acordo com o teste de aceitação, todas as amostras apresentaram boa aceitação em todos os atributos avaliados. Desta maneira, a análise do perfil sensorial da amostra C, que contém proteína de soja na sua formulação, revelou que este ingrediente não foi percebido pelos provadores, e não interferiu na sua aceitação.

Development and assessment of acceptability and nutritional properties of a light snack

A light snack was developed using a fat replacer as a flavor fixative agent. The product presented a calorie reduction of up to 47.5% in comparison with products available on the market. The impact of this fat replacer on the sensory properties was determined by comparing this light snack to the traditional ones. No significant difference in texture was observed; however, there was a difference in color (deltaE = 8.67), due mainly to luminosity (deltaL = 7.79). The light snack presented high sensory acceptability (7.27 ± 1.3; 82.5% of grades were > 7 on 9-point hedonic scale); no significant difference in snack acceptability was observed. However, the traditional snack was significantly preferred in sensory terms (p < 0.05). In an opinion survey when the consumers were informed about snack composition, 75% of them said that they would buy the light snack instead of the traditional one. The caloric and fat reductions allow the use of the claims "light snack" and "fat free", in accordance with the legislation of various countries. We conclude that it is technologically possible to use a fat replacer in snack production, resulting in a sensory acceptable light snack with great potential to replace traditional ones.

Influência de diferentes agentes de corpo nas características reológicas e sensoriais de chocolates diet em sacarose e light em calorias

Foram estudados diferentes agentes de corpo na substituição total da sacarose na formulação de chocolate, buscando-se obter um produto diet em sacarose e light em calorias (25% de redução calórica teórica em relação à formulação padrão, com sacarose) e com boa aceitação sensorial. Os agentes de corpo utilizados neste estudo foram: polidextrose, inulina, frutooligossacarídeos - FOS, lactitol e maltitol; como edulcorante de alta intensidade empregou-se a sucralose. Os chocolates light obtidos foram submetidos às análises de umidade (Karl Fisher), tamanho de partículas (micrômetro digital) e propriedades reológicas (viscosidade plástica - etaca e limite de escoamento de Casson - tauca). O teor de umidade dos chocolates light variou de 1,23 a 2,12%; o tamanho de partículas de 19 a 24 µm; o etaca de 6,60 a 11,00 Pa.s; e o tauca de 0,05 a 1,31 Pa. As formulações com polidextrose, polidextrose e lactitol e polidextrose e maltitol foram selecionadas para análise sensorial por apresentarem boa performance tecnológica e adequada maquinabilidade da massa de chocolate durante as diferentes etapas do processo. A análise sensorial indicou que as três formulações avaliadas não diferiram entre si ao nível de significância de 5% em relação à intensidade do aroma, dureza, derretimento na boca e sabor e, quanto à intenção de compra, as amostras diferiram entre si ao nível de significância de 5%, sendo que a formulação que continha 32,60% de Polidextrose e 15,57% de Maltitol foi a preferida.

Evaluation of Brazilian light ketchups II: quantitative descriptive and physicochemical analysis

Samples of ketchup available on the Brazilian market, one traditional (sweetened with sucrose) and three light versions (sweetened with aspartame, acesulfame-K and a blend of cyclamate, saccharin and stevia) were evaluated for their physicochemical characteristics and sensory profile (Quantitative Descriptive Analysis). Four main groups of attributes were generated: appearance, oral texture, aroma and flavor. The samples presented significant differences in all attributes, except for syneresis and overripe tomato flavor. The highest means for sweetener and bitter tastes and aftertastes were observed for the samples sweetened with acesulfame-K and the blend of sweeteners. Although different characteristics were observed among the products evaluated and, despite the differences in the formulations, the light ketchup sweetened with aspartame was the one that presented properties most similar to those of the traditional ketchup.

Avaliação do perfil sensorial de chá light sabor pêssego

No presente estudo foi determinado o perfil sensorial e a aceitação de três marcas comerciais de chá light sabor pêssego, denominadas A, B e C, acondicionadas em embalagem PET e adquiridas no comércio local. O perfil sensorial foi determinado por Análise Descritiva Quantitativa (ADQ) utilizando-se uma equipe de 11 provadores rigorosamente selecionados e treinados. A aceitação dos produtos foi avaliada por 33 consumidores representativos do público alvo. Os resultados da ADQ foram submetidos à Análise de Variância (ANOVA), Teste de Média de Tukey e Análise de Componentes Principais. As amostras comerciais apresentaram perfis semelhantes em alguns termos descritores e diferenças significativas em outros. A amostra A caracterizou-se principalmente pelos atributos aroma e sabor de banana passa; a amostra B por aroma artificial de pêssego e refrescância; e a amostra C por aroma natural de pêssego e doçura. O Teste Afetivo, analisado por ANOVA e Teste de Média de Tukey, indicou maior aceitação para a amostra C. A cor das amostras foi avaliada pelo método Cielab L*a*b*, sendo que a amostra C se destacou das demais pela cor vermelha.

Effect of extracts from araticum (Annona crassiflora) on CCl4-induced liver damage in rats

The influence of ethanolic extracts of Annona crassiflora on the activities of hepatic antioxidant enzymes was examined. Extracts of A. crassiflora seeds and peel were administered orally (50 mg of galic acid equivalents.kg-1) to Wistar rats for 14 consecutive days followed by a single oral dose of carbon tetrachloride (CCl4, 2 g.kg-1). Lipid peroxidation and the activities of hepatic catalase (CAT), cytochromes P450 (CP450) and b5, glutathione peroxidase (GPx), glutathione reductase (GRed), superoxide dismutase (SOD), and the content of glutathione equivalents (GSH) were evaluated. The treatment with CCl4 increased lipid peroxidation, the level of GSH equivalents and the content of cytochrome b5 by 44, 140 and 32%, respectively, with concomitant reductions of 23, 34 and 39% in the activities of CAT, SOD, and CP450, respectively. The treatment with A. crassiflora seeds and peel extracts alone inhibited lipid peroxidation by 27 and 22%, respectively without affecting the CP450 content. The pretreatment with the A. crassiflora extracts prevented the lipid peroxidation, the increase in GSH equivalents and the decrease in CAT activity caused by CCl4, but it had no effect on the CCl4-mediated changes in CP450 and b5 and SOD. These results show that A. crassiflora seeds and peel contain antioxidant activity in vivo that could be of potential therapeutic use.

Physical-chemical, caloric and sensory characterization of light jambolan (Syzygium cumini Lamarck) jelly

In Brazil, several little economically explored fruits have good potential as raw material for the agro-industry. This study aimed to produce and determine the physical-chemical and sensory characteristics of light jambolan jelly. This fruit has intense purple color, which gave the jellies - both standard and light - a quite attractive visual aspect. The light jellies exhibited similar physical-chemical characteristics to the ones developed through the conventional method and; with the proportion of sweeteners used, the caloric values of the formulations were reduced to the range of 41 to 53%, attending the requirements of the Brazilian legislation for this type of product. The sensory profile obtained for the 4 light formulations developed, clearly showed the tasters' preference for the jelly elaborated with the association of cyclamate and saccharin. Thus, the results revealed good perspectives for the application of this fruit in the food industry.

Effects of the mechanical damage on the water absorption process by corn kernel

The purpose of this study was to investigate and model the water absorption process by corn kernels with different levels of mechanical damage Corn kernels of AG 1510 variety with moisture content of 14.2 (% d.b.) were used. Different mechanical damage levels were indirectly evaluated by electrical conductivity measurements. The absorption process was based on the industrial corn wet milling process, in which the product was soaked with a 0.2% sulfur dioxide (SO2) solution and 0.55% lactic acid (C3H6O3) in distilled water, under controlled temperatures of 40, 50, 60, and 70 ºC and different mechanical damage levels. The Peleg model was used for the analysis and modeling of water absorption process. The conclusion is that the structural changes caused by the mechanical damage to the corn kernels influenced the initial rates of water absorption, which were higher for the most damaged kernels, and they also changed the equilibrium moisture contents of the kernels. The Peleg model was well adjusted to the experimental data presenting satisfactory values for the analyzed statistic parameters for all temperatures regardless of the damage level of the corn kernels.

Influence of physical damage and freezing on histamine concentration and microbiological quality of yellowfin tuna during processing

Yellowfin tuna has a high level of free histidine in their muscle, which can lead to histamine formation by microorganisms if temperature abuse occurs during handling and further processing. The objective of this study was to measure levels of histamine in damaged and undamaged thawed muscle to determine the effect of physical damage on the microbial count and histamine formation during the initial steps of canning processing and to isolate and identify the main histamine-forming microorganisms present in the flesh of yellowfin tuna. Total mesophilic and psicrophilic microorganisms were determined using the standard plate method. The presence of histamine-forming microorganisms was determined in a modified Niven's agar. Strains were further identified using the API 20E kit for enterobacteriaceae and Gram-negative bacilli. Physically damaged tuna did not show higher microbiological contamination than that of undamaged muscle tuna. The most active histamine-forming microorganism present in tuna flesh was Morganella morganii. Other decarboxylating microorganisms present were Enterobacter agglomerans and Enterobacter cloacae. Physical damage of tune during catching and handling did not increase the level of histamine or the amount of microorganisms present in tuna meat during frozen transportation, but they showed a higher risk of histamine-forming microorganism growth during processing.

Is All Fair in Law and War? The Ambiguous Principle of Proportionality of Collateral Damage and the CIA Drone Attacks in Pakistan

Tutkielma käsittelee Yhdysvaltain CIAn miehittämättömiä lennokki-iskuja Pakistanissa kansainvälisen humanitaarisen oikeuden suhteellisuusperiaatteen näkökulmasta. Suhteellisuusperiaatteen mukaan aseellisista iskuista saatavan sotilaallisen hyödyn tulee olla suhteellinen verrattuna siviileille aiheutuvaan haittaan. CIAn iskuja Pakistanissa on kritisoitu, että ne eivät täytä suhteellisuusperiaatteen asettamia vaatimuksia. Tutkielmassa perehdytään ensinnäkin selvittämään ne velvollisuudet, jotka suhteellisuusperiaate asettaa hyökkääjille. Sen jälkeen CIAn lennokki-iskuja tutkitaan näiden velvollisuuksien valossa. Tutkielmassa pyritään selvittämään antaako suhteellisuusperiaatteen luomat oikeudelliset velvollisuudet riittävää suojaa Pakistanin siviileille lennokki-iskujen tuhoja vastaan. Lisäksi pyritään selvittämään, onko lennokki-iskuissa viitteitä suhteellisuusperiaatteen vastaisista iskuista. Tutkimusmenetelmänä käytetään positivistista lainopin metodia, jonka avulla selvitetään voimassa olevaa kansainvälisen humanitaarisen tapaoikeuden suhteellisuusperiaatteen sisältöä. Oikeudellisina lähteinä käytetään pääasiassa humanitaarista tapaoikeutta, mutta tulkinnallisena apuna myös kansainvälisiä sopimuksia sekä oikeuden päätöksiä. Lisäksi oikeudellinen kirjallisuus on tutkimuksessa tärkeässä asemassa. Tutkimuksessa päädytään siihen, että suhteellisuusperiaatteen asettamat velvollisuudet hyökkääjälle ovat niin epämääräiset, että ne eivät anna riittävää suojaa siviileille. Ensinnäkin hyökkääjä voi määrittää sotilaallisen hyödyn omien päämääriensä mukaisesti suhteellisuusanalyysissä. Lisäksi kynnys sille, mikä katsotaan suhteellisuusperiaatteen vastaisuudeksi on hyvin epämääräinen ja korkea. Tämän vuoksi varotoimenpiteet iskujen suunnittelussa ovat hyvin tärkeässä asemassa myös suhteellisuusanalyysissä. Kuitenkin jos hyökkääjä edes jossain määrin osoittaa, että on tehnyt iskut hyvässä uskossa niiden laillisuudesta, iskujen katsotaan yleensä olevan suhteellisuusperiaatteen mukaisia. CIAn lennokki-iskuissa Pakistanissa on viitteitä suhteellisuusperiaatteen vastaisuudesta erityisesti ”tunnusmerkki-iskujen” osalta. ”Tunnusmerkki-iskut” johtavat yleensä vain vähäiseen sotilaalliseen hyötyyn aiheuttaen silti siviiliuhreja. Lisäksi erityisesti tunnusmerkki-iskuissa edellytetään korkeampaa tarkkuutta varotoimenpiteissä. Kuitenkin useat siviiliuhrit voivat merkitä sitä, että näitä varotoimenpiteitä ei ole noudatettu iskuissa.

X-Ray analysis to assess mechanical damage in sweet corn seeds

The X-ray test is a precise, fast and non-destructive method to detect mechanical damage in seeds. In the present study, the efficiency of X-ray analysis in identifying the extent of mechanical damage in sweet corn seeds and its relationship with germination and vigor was evaluated. Hybrid 'SWB 551' (sh2) seeds with round (R) and flat (F) shapes were classified as large (L), medium (M1, M2 and M3) and small (S), using sieves with round and oblong screens. After artificial exposure to different levels of damage (0, 1, 3, 5 and 7 impacts), seeds were X-rayed (15 kV, 5 min) and submitted to germination (25 °C/5 days) and cold (10 °C/7 days) tests. Digital images of normal and abnormal seedlings and ungerminated seeds from germination and cold tests were jointly analyzed with the seed X-ray images. Results showed that damage affecting the embryonic axis resulted in abnormal seedlings or dead seeds in the germination and cold tests. The X-ray analysis is efficient for identifying mechanical damage in sweet corn seeds, allowing damage severity to be associated with losses in germination and vigor.

Alternative electron transfer routes involved in photoprotection of cyanobacteria

In oxygenic photosynthesis, the highly oxidizing reactions of water splitting produce reactive oxygen species (ROS) and other radicals that could damage the photosynthetic apparatus and affect cell viability. Under particular environmental conditions, more electrons are produced in water oxidation than can be harmlessly used by photochemical processes for the reduction of metabolic electron sinks. In these circumstances, the excess of electrons can be delivered, for instance, to O2, resulting in the production of ROS. To prevent detrimental reactions, a diversified assortment of photoprotection mechanisms has evolved in oxygenic photosynthetic organisms. In this thesis, I focus on the role of alternative electron transfer routes in photoprotection of the cyanobacterium Synechocystis sp. PCC 6803. Firstly, I discovered a novel subunit of the NDH-1 complex, NdhS, which is necessary for cyclic electron transfer around Photosystem I, and provides tolerance to high light intensities. Cyclic electron transfer is important in modulating the ATP/NADPH ratio under stressful environmental conditions. The NdhS subunit is conserved in many oxygenic phototrophs, such as cyanobacteria and higher plants. NdhS has been shown to link linear electron transfer to cyclic electron transfer by forming a bridge for electrons accumulating in the Ferredoxin pool to reach the NDH-1 complexes. Secondly, I thoroughly investigated the role of the entire flv4-2 operon in the photoprotection of Photosystem II under air level CO2 conditions and varying light intensities. The operon encodes three proteins: two flavodiiron proteins Flv2 and Flv4 and a small Sll0218 protein. Flv2 and Flv4 are involved in a novel electron transport pathway diverting electrons from the QB pocket of Photosystem II to electron acceptors, which still remain unknown. In my work, it is shown that the flv4-2 operon-encoded proteins safeguard Photosystem II activity by sequestering electrons and maintaining the oxidized state of the PQ pool. Further, Flv2/Flv4 was shown to boost Photosystem II activity by accelerating forward electron flow, triggered by an increased redox potential of QB. The Sll0218 protein was shown to be differentially regulated as compared to Flv2 and Flv4. Sll0218 appeared to be essential for Photosystem II accumulation and was assigned a stabilizing role for Photosystem II assembly/repair. It was also shown to be responsible for optimized light-harvesting. Thus, Sll0218 and Flv2/Flv4 cooperate to protect and enhance Photosystem II activity. Sll0218 ensures an increased number of active Photosystem II centers that efficiently capture light energy from antennae, whilst the Flv2/Flv4 heterodimer provides a higher electron sink availability, in turn, promoting a safer and enhanced activity of Photosystem II. This intertwined function was shown to result in lowered singlet oxygen production. The flv4-2 operon-encoded photoprotective mechanism disperses excess excitation pressure in a complimentary manner with the Orange Carotenoid Protein-mediated non-photochemical quenching. Bioinformatics analyses provided evidence for the loss of the flv4-2 operon in the genomes of cyanobacteria that have developed a stress inducible D1 form. However, the occurrence of various mechanisms, which dissipate excitation pressure at the acceptor side of Photosystem II was revealed in evolutionarily distant clades of organisms, i.e. cyanobacteria, algae and plants.