Optimization of ultrasound-assisted extraction of sorghum phenolics and effect on the stability of 3-deoxyanthocyanins.

Sorghum 3-deoxyanthocyanins (3-DXAs) have greater stability when compared to other anthocyanins. However, the efficiency in extracting these phenolic compounds from cereals, using conventional methods, is low, because most of them are bound to the cell wall. Thus, the aim of this study was to optimize the ultrasound-assisted extraction (UAE) of anthocyanins and total phenolics from sorghum flour, and evaluate the stability of the 3-DXAs. Two frequencies (25 and 45 kHz) were applied in a Central Composite Rotational design to investigate the effect of the variables time (5-75 min) and temperature (30-65°C) using the UAE, with amplitude of the ultrasonic power set at 400 W. In addition, the stability of the 3-DXAs present in the extracts was evaluated. It was possible to successfully optimize the extraction of total anthocyanins (both frequencies) and phenolics (at 45 kHz), and then to obtain equations, to predict their concentrations, with high R2 . The efficiency of UAE was observed, increasing the yield of total anthocyanins, phenolics, and antioxidant capacity at the frequencies of 25 and 45 kHz by 30% and 27%, 10% and 5%, and 30% and 15%, respectively. The apigeninidin was the major 3-DXA found in the extracts, and the luteolinidin was the most stable over storage time. Overall, there was no difference in the 3-DXAs stability obtained by the UAE compared to the conventional method. Thus, ultrasound is an alternative to obtaining sorghum extracts rich in 3-DXAs and other phenolic compounds. PRACTICAL APPLICATION: The health benefits of sorghum 3-deoxyanthocyanins coupled with the growing interest of the food industry in producing healthier food products have motivated this study, because it is important to find ways to optimize 3-deoxyanthocyanins extraction. We have demonstrated that ultrasound-assisted extraction was efficient in extracting high amounts of 3-deoxyanthocyanins and other phenolics from sorghum flour. Moreover, some 3-deoxyanthocyanins have shown to be more stable than others after extraction. Thus, the ultrasound has great potential to produce sorghum phenolic extracts rich in 3-deoxyanthocyanins, which can be used as natural colorants and functional ingredients in foods.

Ultrasonic pre-treatment to enhance drying of potentially probiotic guava (Psidium guajava): Impact on drying kinetics, Lacticaseibacillus rhamnosus GG viability, and functional quality.

This study aimed to evaluate the effects of ultrasound (US) on the drying acceleration of potentially probiotic guava, including its impact on drying kinetics, probiotic (Lacticaseibacillus rhamnosus GG) viability, and functional quality of the product during drying. To perform US pre-treatments, one group of samples were first pre-treated by US (38 W/L, 25 kHz) for 15 and 30 min and then immersed in the probiotic solution for 15 or 30 min, and another group of samples were submerged in the probiotic solution simultaneously applying US (US-assisted) for 15 and 30 min. After pre-treatments, the samples were convectively dried at 60 °C. Based on the results, all US pre-treatments improved the drying rate (up to 59%) and reduced the drying time (up to 31%) to reach 25% moisture compared to non-sonicated samples. The reduction in drying time (from ∼6 h to ∼4 h for US pre-treated samples) was crucial for maintaining the probiotic viability in the dehydrated guavas. These samples showed counts of 6.15 to 7.00 CFU∙g-1 after 4 h, while the control samples reached counts of 4.17 to 4.45 CFU∙g-1 after 6 h. US pre-treatment did not affect the color parameters of the samples before drying (p > 0.05). The functional compounds were reduced during drying (p < 0.05), however, all US pre-treated samples had lower reductions in vitamin C content (up to 20%), phenolic compounds (up to 41%) and antioxidant capacity (up to 47%) compared to control samples (up to 52%, 81% and 61%, respectively). Therefore, US pre-treatment (highlighting the US-assisted probiotic incorporation for 30 min) reduced the drying time for guava slices and minimized the thermal impact on probiotic viability and functional compounds, being a strategy to produce potentially probiotic dehydrated guava.

Impact of different roasting conditions on the chemical composition, antioxidant activities, and color of Coffea canephora and Coffea arabica L. samples.

This work aimed to evaluate the physicochemical changes during the roasting process of Robusta and Arabica coffee. The highest content of total phenolics was detected in roasted coffee at temperatures of 135 °C/20.20 min, 210 °C/9.02 min, 210 °C/11.01 min, and 220 °C/13.47 min for both species. Robusta coffee showed greater antioxidant activity compared to Arabica coffee, except for the profiles at 230 °C/17.43 min and 275 °C/7.46 min that did not differ between samples by the DPPH and FRAP methods. For Arabica coffee, the antioxidant activity was independent of the roasting profile used. Robusta coffee presented higher values of the indexes b* (intensity of yellow vs blue), c* (chroma) and hue, being characterized as lighter and with greater chroma and hue. The highest levels of caffeoylquinic acid (5-CQA) were observed in Robusta coffee. Arabica coffee had lower trigonelline values. Caffeic acid and hydroxymethylfurfural were identified only in Robusta coffee. However, the results provided solid knowledge for the design of general properties and chemical compounds generated from binomials of roasting time and temperature that are little used in the world market.

Use of maltodextrin, sweet potato flour, pectin and gelatin as wall material for microencapsulating Lactiplantibacillus plantarum by spray drying: Thermal resistance, in vitro release behavior, storage stability and physicochemical properties.

Different plant products and co-products have been studied as wall materials for the microencapsulation of probiotics due to the need for new lost-cost, abundant, and natural materials. In this study, microparticles were developed by spray drying using different combinations of conventional materials such as maltodextrin, pectin, gelatin, and agar-agar with unconventional materials such as sweet potato flour to microencapsulate Lactiplantibacillus plantarum. The microparticles obtained were evaluated for encapsulation efficiency, thermal resistance, and rupture test. The most resistant microparticles were characterized and evaluated for probiotic viability during storage and survival to in vitro gastrointestinal conditions. Microparticles A (10 % maltodextrin, 5 % sweet potato flour, and 1 % pectin) and B (10 % maltodextrin, 4 % sweet potato flour, and 2 % gelatin) showed high thermal resistance (>59 %) and survival in acidic conditions (>80 %). L. plantarum in microparticles A and B remained viable with counts > 6 log CFU.g-1 for 45 days at 8 °C and -18 °C and resisted in vitro gastrointestinal conditions after processing with counts of 8.38 and 9.10 log CFU.g-1, respectively. Therefore, the selected microparticles have great potential for application in different products in the food industry, as they promote the protection and distribution of probiotic microorganisms.

Betalains nanodispersions: Effects on betalains stability and on rheological properties of Greek yogurt.

Red beetroot (Beta vulgaris L.) is a great source of betalains. The main betalains are the betacyanins, responsible for the purple color, and betaxanthins, which present a brownish color. These pigments can present antioxidant activity and are very unstable under certain conditions, such as temperature, extreme ranges of pH, and exposure to light. The aim of this work was to obtain beetroot extract (BE) via ultrasound and transform it into nanoparticles by using polyethylene glycol (PBE) and polyethylene glycol with low molecular weight chitosan (PCBE) as dispersants. The stability of the main betalains in the nanodispersions and the effects of the nanodispersions on the color and rheological properties of commercial Greek yogurt were evaluated. Compared to pristine BE, PCBE nanoparticles presented increased stability for the main betalains in acidic conditions (pH 3.0 and 5.0) of 56% and 22%, respectively. Both PBE and PCBE showed enhanced relative thermal stability compared to pristine BE. Furthermore, PCBE improved commercial Greek yogurt's rheological properties and color parameters. PCBE nanodispersions can be successfully applied as a color additive to commercial Greek yogurt.

Evaluation of the efficacy of toasted white and tannin sorghum flours to improve oxidative stress and lipid profile in vivo.

The objective of the present work was to evaluate and compare the effect of toasted white and tannin sorghum flours on lipid metabolism and antioxidant potential in vivo. Male spontaneously hypertensive rats (SHR) were induced to oxidative stress with paracetamol and fed a normal diet (AIN-93M) and diets containing toasted tannin sorghum flour and toasted white sorghum flour (without tannins), replacing 100% cellulose, during 29 days. Hepatotoxicity was assessed by biochemical tests and by quantifying oxidative stress markers. Groups that received toasted sorghum flour with and without tannins showed reduction of alanine aminotransferase (ALT) concentration and improvement of lipid profile, with increase of high-density lipoprotein (HDL) compared to paracetamol control, and did not differ statistically from the AIN-93M control. Moreover, toasted white sorghum flour presented similar efficacy in reducing oxidative stress in liver tissue compared to toasted tannin sorghum flour, although the former had lower total phenolic content and antioxidant capacity, suggesting a greater effect of small phenolic compounds, such as phenolic acids, in the prevention of oxidative stress. Therefore, toasted white and tannin sorghum flours had similar efficacy to improve the lipid profile and oxidative stress in rats treated with paracetamol, constituting potential sources of antioxidants, which can be used as promising ready-to-eat foods and as ingredients for the development of sorghum-based products. PRACTICAL APPLICATION: The health benefits of sorghum coupled with the growing interest of the food industry in producing healthier food products have motivated the development of toasted sorghum flours as potential sources of antioxidants and dietary fiber. We have demonstrated that consumption of toasted white and tannin sorghum flours by rats treated with paracetamol had similar efficacy to improve oxidative stress and lipid profile. Thus, these toasted sorghum flours have great potential to be used by the food industry as ready-to-eat foods or as ingredients in the development of various food products.

Optimization of pectin extraction from Ubá mango peel through surface response methodology.

A central composite design was used to determine effects of pH (1.16-2.84), extraction temperature (63-97°C) and time (35-85min) on the yield, degree of degree of esterification (DE) and viscosity of pectins extracted. For pectin extraction, the previously sanitized mango shells were dried and crushed to obtain the flour that was treated with an ethanol solution obtaining the alcohol insoluble residue (AIR). Subsequently, the AIR was mixed in ethanol with the extraction solution of hydrochloric acid. Pectin yields ranged from 18.8 to 32.1g/100g of AIR, whereas the degree of esterification (DE) and viscosity values ranged from 62.2 to 86.2% and from 1.58 to 45.85mPa·s, respectively. An inverse correlation was found between extraction yield and viscosity. Relying upon the desirability function, two optimum conditions were determined: 35min30% from the AIR, DE≥70.0% and η≥20.0mPa·s.

Optimization of ultrasound-assisted extraction of phenolic compounds from jussara (Euterpe edulis M.) and blueberry (Vaccinium myrtillus) fruits

Abstract This study was aimed at optimizing the ultrasound-assisted extraction (UAE) of phenolic compounds from jussara and blueberry fruits using the response surface methodology (RSM). UAE was found to be more efficient to extract phenolic compounds from both fruits than the conventional extraction. The optimum extraction conditions for the jussara fruits were: extraction time between 30 and 62 min for total anthocyanins and total phenolics, fruit:solvent ratio of 10% and 6% (w/v) for total anthocyanins and total phenolics, respectively. The ethanol concentration was non-significant (p> 0.05). Acidified water was found to be an extracting solvent as efficient as ethanol in the extraction of phenolic compounds from jussara fruits. The optimum extraction conditions for blueberry anthocyanins were: ethanol concentration between 20-70% vol, and fruit: solvent ratio greater than 20% (w/v) within the range studied. The extraction time was not significant (p> 0.05). For total phenolic content: the concentration of ethanol was between 40-80%, and fruit: solvent ratio greater than 20% (w/v) and extraction time over 50 minutes. It was possible to adjust the mathematical model for the coordinates a* (verde vs vermelho) and C* (color saturation) of the jussara extracts.

Flavonols and ellagic acid derivatives in peels of different species of jabuticaba (Plinia spp.) identified by HPLC-DAD-ESI/MSn.

Extracts of jabuticaba peels show complex chromatographic profiles at 360 nm, with some peaks presenting UV-Vis spectra resembling those of flavonol glycosides and others resembling that of ellagic acid. The presence and tentative identification of these phenolic compounds were comprehensively studied in four species of Brazilian jabuticaba fruit - Plinia trunciflora, variety 'jabuticaba de cabinho'; P. caulifora, varieties 'jabuticaba paulista' and 'jabuticaba canaã-açu'; P. jaboticaba, variety 'jabuticaba sabará'; and P. phitrantha, variety 'jabuticaba branca-vinho' - using HPLC-DAD-ESI-MSn. Seventeen flavonols derived from quercetin and three from myricetin and eighteen derivatives of ellagic acid and eleven of methyl ellagic acid were detected. Most of them were newly described and mainly occurred in glycosylated and acylglycosylated forms. Some compounds were missing in one variety, such as the absence of methyl ellagic acid derivatives in 'jabuticaba branca-vinho', and others only appeared in one variety, thus suggesting potential capacity for varietal differentiation.

Teor de vitamina C, β-caroteno e minerais em camu-camu cultivado em diferentes ambientes / Levels of vitamin C, β-carotene and minerals in camu-camu cultivated in different environments

RESUMO: O objetivo deste trabalho foi avaliar a influência do tipo de cultivo (ambiente seco e alagado) sobre o teor de vitamina C, β-caroteno e minerais (cálcio, magnésio, enxofre, zinco, ferro, manganês, cobre, boro, nitrogênio, fósforo e potássio) de camu-camu. As vitaminas citadas foram determinadas por cromatografia líquida de alta eficiência, enquanto que os minerais cálcio, magnésio, zinco, cobre, manganês e ferro por espectrometria de absorção atômica, o potássio por fotometria de chama e o fósforo, boro e enxofre por espectrofotometria, nos comprimentos de onda 725 e 420nm, respectivamente. O fruto cultivado em ambiente seco apresentou maior (P<0,05) teor de vitamina C (13.756,79mg 100g1/peso seco) e da maioria dos minerais investigados (cálcio, magnésio, enxofre, ferro, cobre, nitrogênio, fósforo e potássio). Os teores de β-caroteno não variaram (P>0,05) em função dos diferentes ambientes.

ABSTRACT: The aim of this study was to evaluate the influence of crop type (dry and flooded environment) on vitamin C, β-carotene and minerals (calcium, magnesium, sulfur, zinc, iron, manganese, copper, boron, nitrogen, phosphorus and potassium), of camu-camu content. Vitamins were determined by high performance liquid chromatography, calcium, magnesium, zinc, copper, manganese and iron by atomic absorption spectrometry, potassium by flame photometry and phosphorous, boron and sulfur by spectrophotometry in wave lengths 725 and 420nm, respectively. Fruit grown in a dry environment showed higher (P<0.05) vitamin C content (13756.79mg 100g-1/dry weight) and generally higher mineral content (calcium, magnesium, sulfur, iron, copper, nitrogen, phosphorus and potassium). β-carotene content was not influenced (P>0.05) by different environments.

Anti-inflammatory activity of polyphenolics from açai (Euterpe oleracea Martius) in intestinal myofibroblasts CCD-18Co cells.

The demand for tropical fruits high in polyphenolics including açai (Euterpe oleracea Mart.) has been increasing based on ascribed health benefits and antioxidant properties. This study evaluated the anti-inflammatory activities of açai polyphenolics in human colon myofibroblastic CCD-18Co cells to investigate the suppression of reactive oxygen species (ROS), and mRNA and protein expression of inflammatory proteins. Non-cytotoxic concentrations of açai extract, 1-5 mg gallic acid equivalent L(-1), were selected. The generation of ROS was induced by lipopolysaccharide (LPS) and açai extract partially reversed this effect to 0.53-fold of the LPS-control. Açai extract (5 mg GAE L(-1)) down-regulated LPS-induced mRNA-expression of tumor necrosis factor alpha, TNF-α (to 0.42-fold), cyclooxygenase 2, COX-2 (to 0.61-fold), toll-like receptor-4, TLR-4 (to 0.52-fold), TNF receptor-associated factor 6, TRAF-6 (to 0.64-fold), nuclear factor kappa-B, NF-κB (to 0.76-fold), vascular cell adhesion molecule 1, VCAM-1 (to 0.71-fold) and intercellular adhesion molecule 1, ICAM-1 (to 0.68-fold). The protein levels of COX-2, TLR-4, p-NF-κB and ICAM-1 were induced by LPS and the açai extract partially reversed this effect in a dose-dependent manner. These results suggest the anti-inflammatory effect of açai polyphenolic extract in intestinal cells are at least in part mediated through the inhibition of ROS and the expression of TLR-4 and NF-κB. Results indicate the potential for açai polyphenolics in the prevention of intestinal inflammation.

Preparation of dry extract of Mikania glomerata Sprengel (Guaco) and determination of its coumarin levels by spectrophotometry and HPLC-UV.

Guaco (Mikania glomerata Sprengel) syrup is one of the most popular herbal medicines used to treat the symptoms of asthmatic bronchitis, cough and hoarseness. The coumarin 2H-1-benzopyran-2-one, is one of the major constituents of Guaco and contributes to its pharmacological effects. The pharmaceutical capsule form of dry extract of Guaco is recommended by the Brazilian Program of Medicinal Plants and Herbal Medicines and used in primary health care. In order to identify a new protocol to obtain the raw material for Guaco capsule production we evaluated two methods, including a freezedrying process (lyophilization) and the spray-dryer technique, as well as the use of two adjuvants, Maltodextrins and Aerosil®, in different concentrations. The coumarin levels of the dried extracts were analyzed by UV-spectrophotometry and HPLC-UV/DAD. The adjuvant Aerosil® 8% showed better dry powder physical appearance. Lyophilization was observed to be the best process to obtain the dry extract of Guaco based on the measured coumarin levels.

Campo elétrico pulsado / Pulsed electric field

Campos elétricos pulsados de alta intensidade (CEPAI) constituem um método não-térmico de conservação para alimentos em substituição à pasteurização tradicional. Em comparação ao processamento térmico, os CEPAI, além de serem eficientes na eliminação de micro-organismos e na inativação de enzimas, também minimizam as perdas de sabor, cor, textura, nutrientes e componentes termolábeis dos alimentos. O objetivo desse trabalho foi levantar dados bibliográficos atuais sobre o tema CEPAI, abordando: definição do processo, instalação experimental, efeito da ruptura dielétrica do alimento, efeito sobre micro-organismo, enzimas e constituintes dos alimentos. Os dados encontrados na literatura apontam o tratamento por CEPAI como alternativa promissora para a conservação de alimentos, podendo ser utilizado como tecnologia única ou como complemento aos processamentos térmicos.

Pulsed electric fields of high intensity (HIPEF) is a non-thermal food conservation to replace traditional thermal pasteurization. Compared to thermal processing, the HIPEF as well as being effective in removing microorganisms and inactivate enzymes also minimize the loss of flavor, color, texture, nutrients and labile components of food. The aim of this work was to gather bibliographic data current HIPEF on the subject, covering: experimental setup, effects of dielectric breakdown of food, effect on microorganisms, enzymes and constituents of food. The data found in the literature indicate treatment of HIPEF as a promising alternative for food conservation and it could be used as a single technology or in addition to thermal processing.

Pharmacological properties of the ethanol extract of Muehlenbeckia platyclada (F. Muell.) meisn. leaves.

Antinociceptive and anti-inflammatory activities of the Muehlenbeckia platyclada leaves' ethanol extract were investigated in animal models. The extract (p.o.) reduced the number of abdominal contortions induced by acetic acid by 21.57% (400 mg/kg). After intraplantar injection of formalin, a dose of 400 mg/kg (p.o.) inhibited the time spent paw licking in the first phase (26.43%), while the second phase was inhibited by 10.90 and 36.65% at the doses of 200 and 400 mg/kg, respectively. The extract (p.o.) increased the reaction time on a hot plate at a dose of 400 mg/kg (32.68 and 40.30%) after 60 and 90 minutes of treatment, respectively. The paw edema was reduced by extract (p.o.) at doses of 100 (15.46 and 16.67%), 200 (22.68 and 25.64%) and 400 mg/kg (29.50 and 37.33%) after 3 to 4 h of carrageenan application, respectively. Doses of 100, 200 and 400 mg/kg (p.o.), administered 4 h after the carrageenan injection, reduced the exudate volume (11.28, 21.54 and 45.13%), while leukocyte migration was reduced by 21.21 and 29.70% at the doses of 200 and 400 mg/kg, respectively. These results indicate that the ethanol extract from M. platyclada may constitute a potential target for the discovery of new molecules with antinociceptive and anti-inflammatory activities that can be explored for their therapeutic use.

Impacto da luz, pH, ácido ascórbico e glicose na estabilidade de antocianinas da fonte não usual maria-pretinha (solanum americanum, mill) / Impact of light, pH, ascorbic acid and glucose on the stability of supply anthocyanins unsual mary shine (solanum americanum, mill)

O fruto de maria-pretinha (Solanum americanum) consiste em fonte não usual, porém viável de produção de antocianinas. Sendo assim, objetivou-se avaliar a estabilidade do extrato antociânico obtido dessa fonte vegetal, após extração com metanol acidificado (0,05% HCl), frente a fatores degradativos como luz, pH, ácido ascórbico e glicose. Sua estabilidade foi estimada determinando-se os valores de absorbância no comprimento de onda de máxima absorção em função do tempo, mediante os quais foram calculadas as constantes de velocidade de degradação (k) e o tempo de meia-vida (t1/2) de cada sistema. Os efeitos da luz e da concentração de 400 ppm de ácido ascórbico foram os mais destrutivos para a cor do pigmento, especialmente em pH 4,0. A adição de ácido ascórbico acelerou a degradação do pigmento antociânico. A glicose não afetou a estabilidade das antocianinas. Os pigmentos apresentaram maior estabilidade em pH 2,0. A interação negativa de ácido ascórbico e antocianinas merece mais investigações, já que a aplicação de pigmentos antociânicos na indústria de alimentos, especialmente em sucos e refrigerantes, mostrou-se bastante promissora.

Seasonal variation, chemical composition and antioxidant activity of Brazilian propolis samples.

Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin-Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Cândido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginópolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being α- and ß-amyrins. Methanolic extracts from Itapecerica and Paula Cândido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginópolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis.

Carotene and provitamin A content of vegetables sold in Viçosa, MG, Brazil, during spring and winter / Caroteno e provitamina A teor de hortaliças comercializadas em Viçosa, MG, Brasil, durante a primavera e o inverno

This study investigated the α- and β-carotene content and provitamin A value of four leafy vegetables sold at local and street markets in Viçosa, MG, Brazil, in the spring and winter of 2002. Carotenoids were analyzed by high-performance liquid chromatography. α-Carotene was detected in all samples sold during spring, but was only present in a few samples of smooth and curly lettuce and kale in winter. β-Carotene was found in marked quantities in all leafy vegetables analyzed. Duncan's test (α = 5 percent) showed significantly higher α-carotene content in curly lettuce and vitamin A value in large-leaved watercress in the spring. Mean β-carotene content and vitamin A value were 7544, 8751, 2584, 2792, 8193, and 5338 μg/100 g and 666, 760, 227, 238, 698, and 460 μg RAE/100 g in large-leaved and hydroponic watercress, smooth and curly lettuce, kale and spinach, respectively. All leafy vegetables analyzed represent important sources of provitamin A and supply an important part of the daily requirements of children and adults.

Investigou-se o conteúdo de α e β-caroteno e avaliou-se o valor pro-vitamínico A de quatro hortaliças folhosas comercializadas em mercados locais e feira- livre de Viçosa, MG durante a primavera e o inverno de 2002. Os carotenóides foram analisados por Cromatografia Líquida de Alta Eficiência (CLAE). O α-caroteno foi detectado em todas as amostras analisadas na primavera, porém no inverno, somente algumas amostras de alface crespa e lisa, e couve apresentaram tal carotenóide. O β-caroteno foi encontrado, em quantidades apreciáveis, em todas as hortaliças folhosas analisadas. O teste de Duncan (α=5 por cento) detectou que o conteúdo de α-caroteno em alface crespa e o valor de vitamina A em agrião de folha larga foram estatisticamente superiores na primavera. Os teores médios de β-caroteno e de valor de vitamina A para agrião de folha larga e hidropônico, alface crespa e lisa, couve e espinafre foram: 7544; 8751; 2584; 2792; 8193; 5338 μg/100g e 666; 760; 227; 238; 698; 460 μg RAE/100g, respectivamente. Todas as hortaliças folhosas analisadas constituem importantes fontes de provitamina A e suprem grande parte das recomendações diárias de crianças e adultos.

Correlação entre métodos espectrofotométricos e colorimétricos na determinação da foto e termossensibilidade dos carotenoides de tomate / Correlation between spectrophotometric and colorimetric methods for determination of photosensitivity and thermosensitivity of tomato carotenoids

A busca por pigmentos naturais para aplicação em alimentos e o desafio de sua produção industrial tem motivado pesquisadores a investigar sua estabilidade à luz, temperatura, pH e oxigênio. Mistura de licopeno, obtida de polpa de tomate e óleo mineral, foi preparada para se estudar a foto e termossensibilidade do corante. Determinações espectrofotométricas e colorimétricas foram realizadas durante o período de estocagem. O efeito da luz foi mais destrutivo que a maior temperatura avaliada (80 graus C), sobretudo pela descoloração brusca de algumas amostras após 30 dias de estocagem. O pigmento foi pouco afetado quando armazenado no escuro e a 40 graus C. Obtiveram-se correlações significativas nas reduções de absorbãncia com os valores calorimétricos "a", "b" e "h". Essas coordenadas foram as que explicaram melhor as variações ocorridas na decomposição do pigmento.

Carotenos provitamínicos A em hortaliças preparadas em unidades produtoras de refeições comerciais / Provitamin A carotenes in vegetables prepared at production units of commercial meals

Investigou-se o teor de alfa e beta-caroteno e avaliou-se o valor provitamínico A de cinco hortaliças, servidas cruas e/ou submetidas à cocção, em três Unidades Produtoras de Refeições (UPR) Comerciais, localizadas em Viçoza, MG. Abóbora-moranga e vagem foram analisadas na forma cozida, tomate e pimentão na forma crua, e cenoura, em ambas as formas. Os carotenoides foram analisados por Cromatografia a Líquido de Alta Eficiência (CLAE). O alfa-caroteno não foi encontrado em tomate e não foi quantificado em abóbora-moranga, pimentão e vagem (teores abaixo do limite de detecção do método). Cenoura crua ralada foi a hortaliça que apresentou o maior teor de alfa0caroteno (123,74mg/100 g, base sólidos insolúveis). O beta-caroteno foi detectado em todas as hortaliças analisadas, sendo a cenoura cozida em forma de bastão a hortaliça mais rica nesse componente (223,14 mg/100g, base sólidos insolúveis) e a vagem cozida em rodela a hortaliça com teor mais reduzido (5,60 mg/100g, base sólidos insolúveis). Não houve diferença estatísticamente significativa (alfa=5 por cento0 nos teores de alfa e beta-caroteno para abóbora-moranga, cenoura, pimentão e vagem preparados em diferentes formas nos restaurantees estudados. Por outro lado, o teor de beta-caroteno em tomate fatiado em rodelas foi significativamente supeior àquele encontrado em tomates fatiados na forma de cubos nos tres restaurantes estudados, mostrando que esse tipo de fatiamento preserva melhor esse carotenoide. Com relação ao valor de vitamina A obteve-se perfil similar aos resultados encontrados para beta-caroteno, uma vez que esse foi o principal carotenoide provitamínico A encontrado nas hortaliças.

Fatores que influenciam a reação de saponificação dos carotenóides presentes no urucum (Bixa orellana L. ) / Factors that influence saponification reaction in annatto (Bixa orellana L. ) carotenoids

Conduziu-se este trabalho, com o objetivo de estudar o efeito de diferentes concentrações de KOH (0,6 por cento, 1 por cento, 2 por cento, 3 por cento, 4 por cento e 5 por cento) e temperatura de extração (25ºC, 50°C, 60°C e 70°C) na reação de saponificação dos principais pigmentos de urucum. O progresso da reação foi acompanhado pela quantificação do teor de bixina e de norbixina por meio de cromatografia líquida de alta eficiência (CLAE). A maior concentração de base propiciou a maior conversão de bixina em norbixina (KOH 5 por cento - bixina: 0,44 g.100g-1, norbixina: 1,43 g.100g-1) e com a menor concentração não ocorreu conversão (KOH 0,6 por cento - bixina: 2,00 g.100g-1, norbixina: não detectada). A elevação da temperatura de extração esteve associada à redução do teor de bixina no meio e ao aumento do teor de norbixina (T70°C - bixina: 0,01 g.100g-1, norbixina: 2,34 g.100g-1; T25ªC - bixina: 1,04 g.100g-1, norbixina: 0,78 g.100g-1). Sendo assim, para extração de bixina seria recomendado o uso de soluções alcalinas pouco concentradas, ao passo que para a obtenção do pigmento hidrossolúvel são aconselhadas concentrações mais elevadas, podendo estar associadas a aquecimento.

This research aimed to evaluate the effect of different KOH concentrations (0.6 percent, 1 percent, 2 percent, 3 percent, 4 percent and 5 percent) and extraction temperature (25ºC, 50°C, 60°C and 70°C) on the progress of saponification reaction in annatto pigments. The progress of the reaction was monitored by quantification of bixin and norbixin using high performance liquid chromatography (HPLC). The highest alkali concentration made possible the maximum conversion of bixin into norbixin (KOH 5 percent - bixin: 0.44 g.100g-1, norbixin: 1.43 g.100g-1) and using the lowest concentration, saponification didn't take place (KOH 0.6 percent - bixin: 2.00 g.100g-1, norbixin: not detected). The elevation of extraction temperature was associated to a decrease of bixin content and to an increase of norbixin content (T70°C - bixin: 0.01 g.100g-1, norbixin: 2.34 g.100g-1; T25ºC - bixin: 1.04 g.100g-1, norbixin: 0.78 g.100g-1). Therefore, for the extraction of bixin is recommended to use alkaline solutions in low concentrations. To obtain the hydrossoluble pigment, higher concentrations are suggested, and they could be associated to heating.