Valéria Aparecida Vieira Queiroz

Sorghum flour fractions: correlations among polysaccharides, phenolic compounds, antioxidant activity and glycemic index.

Nutrients composition, phenolic compounds, antioxidant activity and estimated glycemic index (EGI) were evaluated in sorghum bran (SB) and decorticated sorghum flour (DSF), obtained by a rice-polisher, as well as whole sorghum flour (WSF). Correlation between EGI and the studied parameters were determined. SB presented the highest protein, lipid, ash, β-glucan, total and insoluble dietary fiber contents; and the lowest non-resistant and total starch contents. The highest carbohydrate and resistant starch contents were in DSF and WSF, respectively. Phenolic compounds and antioxidant activities were concentrated in SB. The EGI values were: DSF 84.5 ± 0.41; WSF 77.2 ± 0.33; and SB 60.3 ± 0.78. Phenolic compounds, specific flavonoids and antioxidant activities, as well as total, insoluble and soluble dietary fiber and β-glucans of sorghum flour samples were all negatively correlated to EGI. RS content was not correlated to EGI.

Desidratação por imersão-impregnação e secagem por convecção de goiaba

O objetivo deste trabalho foi avaliar as caracteristicas fisico-quimicas e sensoriais de goiabas in natura e submetidas a desidratacao por imersao-impregnacao e a secagem complementar por conveccao, alem de avaliar a estabilidade da cor das goiabas secadas apos 30, 60 e 90 dias de armazenamento sob refrigeracao. Amostras de goiaba foram imersas em solucoes de sacarose a 0,4 e 0,5 g mL-1, sacarose a 0,3 g mL-1 + sucralose a 0,2 g L-1, acucar invertido a 41% (p/p) e acucar invertido sem diluicao. Foram avaliados solidos soluveis totais, acidez titulavel, pH, cor, aroma, aparencia, sabor e textura. O teor de solidos soluveis totais das amostras aumentou linearmente em funcao do tempo de imersao, sem efeito significativo do tipo de acucar empregado no preparo da solucao. A preservacao do teor de acido citrico foi mais pronunciada em solucoes menos concentradas de sacarose. Amostras secadas nao submetidas a desidratacao osmotica exibiram maior alteracao de cor do que aquelas previamente desidratadas. Solucoes de sacarose sao mais eficazes na estabilidade da cor do que as de acucar invertido. As goiabas submetidas a desidratacao por imersao-impregnacao tiveram boa aceitacao sensorial, e aquelas secadas apenas por conveccao nao foram aceitas pelos provadores.

Tocochromanols and carotenoids in sorghum (Sorghum bicolor L.): diversity and stability to the heat treatment.

The content and stability (retention) to dry heat in a conventional oven (DHCO) and extrusion of tocochromanols and carotenoids in sorghum genotypes were evaluated. One hundred sorghum genotypes showed high variability in tocochromanol content (280.7-2962.4 μg/100g in wet basis) and 23% of the genotypes were classified as source of vitamin E. The total carotenoid varied from 2.12 to 85.46 μg/100g in one hundred sorghum genotypes. According to the genetic variability for carotenoids and tocochromanols, the 100 genotypes were grouped into 7 groups. The retention of the total tocochromanols and α-tocopherol equivalent decreased after extrusion (69.1-84.8% and 52.4-85.0%, respectively) but increased after DHCO (106.8-114.7% and 109.9-115.8%, respectively). Sorghum carotenoids were sensitive to extrusion (30.7-37.1%) and DHCO (58.6-79.2%). In conclusion, the tocochromanols profile in sorghum varied widely and the genotypes presented high genetic variability for carotenoids and tocochromanols. Sorghum was a source of tocochromanols, which increased after DHCO and decreased after extrusion. The carotenoid content in sorghum decreased after DHCO and extrusion.

In vivo protein quality of new sorghum genotypes for human consumption

The in vivo protein qualities were evaluated in flours from raw sorghum grains (RF) and flours from sorghum grains subjected to heat treatment in an oven (HTF) from the hybrids BRS 305, BRS 309 and BRS 310, developed by the Brazilian Agricultural Research Corporation (Embrapa). There were no differences in feed efficiency ratios among experimental groups. Heat-treated flour from BRS 309 and BRS 310 genotypes had higher protein efficiency ratios and net protein ratio values; however, they did not differ from those of flour from raw grain of BRS 310 genotype. Effects of heat treatment were observed in the BRS 309 genotype. Heat treatment did not affect true digestibility observed for the RF and HTF of the three genotypes. Lysine was the first limiting amino acid of the three sorghum genotypes. The HTF BRS 305 showed the lowest protein digestibility-corrected amino acid score value. Heat treatment improved the protein quality of genotype BRS 309; however, no differences were observed among the other genotypes.

Avaliação nutricional e sensorial de caqui cv Fuyu submetido à desidratação osmótica e secagem por convecção

A crescente preocupacao com a saude humana tem promovido o aumento da demanda pelo consumo de frutas, tanto in natura como processadas. Neste trabalho, foram realizadas as avaliacoes nutricional e sensorial de caqui Fuyu submetido a desidratacao osmotica e secagem por conveccao. Cilindros de caqui com diâmetro de 15 mm e altura de 40 mm foram imersos por 2 horas em solucao com concentracao de sacarose de 0,47 g.mL-1, a 40 oC, utilizando-se relacao fruta/xarope de 1:10 e grau de agitacao de 60 min-1. A reducao do teor de agua ate 17% b.u. foi realizada a 60 oC, empregando-se velocidade do ar de 1,25 m/s. Apos a secagem, foram realizadas as seguintes analises fisico-quimicas: acidez, pH, oBrix, carboidratos, proteinas, lipidios, vitamina C, cinzas, fibras insoluveis e analise sensorial. Os resultados mostraram incremento em todas as caracteristicas fisico-quimicas avaliadas para o caqui desidratado em comparacao ao caqui in natura. A analise sensorial evidenciou que o produto obteve elevado indice de aceitacao, correspondendo ao segundo e terceiro niveis da escala hedonica (gostei muito e gostei regularmente). A caracteristica que influenciou predominantemente a aceitacao do produto foi a textura (88%), seguida do sabor (84%). A aparencia foi o atributo que menos influenciou a aceitacao (80%).

Effect of the storage time and temperature on phenolic compounds of sorghum grain and flour.

This study evaluated the effect of storage temperature (4, 25 and 40°C) and time on the color and contents of 3-deoxyanthocyanins, total anthocyanins, total phenols and tannins of sorghum stored for 180days. Two genotypes SC319 (grain and flour) and TX430 (bran and flour) were analyzed. The SC319 flour showed luteolinidin and apigeninidin contents higher than the grain and the TX430 bran had the levels of all compounds higher than the flour. The storage temperature did not affect most of the analyzed variables. The content of most of the compounds reduced during the first 60days when they became stable. At day 180, the retention of the compounds in the genotypes SC319 and TX430 ranged from 56.1-77.9% and 67.3-80.1% (3-deoxyanthocyanins), 88.4-93.8% and 84.6-96.8% (total anthocyanins) and 86.7-86.8 and 89.4-100% (phenols) respectively. The retention of tannins ranged from 56.6 to 85.3%. The color of samples remained stable for 120days.

Qualidade nutricional de goiabas submetidas aos processos de desidratação por imersão-impregnação e secagem complementar por convecção

During dewatering and impregnation soaking (DIS), transfer of water and of natural compounds from the product to the hypertonic solution occurs, however, few studies have been carried out to identify and quantify the losses of these compounds. Thus, this work reports on the losses of vitamin C and of the following minerals: Na, K, Ca, Mg, Zn and Mn, in red guavas submitted to the combined process of DIS (at 50 oC for 2 hours) and convective drying (at 60 oC and air velocity of 1.25 m/s, to a final moisture content of 20% w.b.). Studies were carried out employing two types of solutes: sucrose (in 0.4 and 0.5 g.mL-1 solutions) and liquid invert sugar (in a 41% w/w solution and as an undiluted syrup). Also, a test was performed using a solution comprised of 0.3 g.mL-1 sucrose and 0.2 g.L-1 sucralose. The control treatment consisted of drying guava solely in the convective drier. The effect of storage conditions on the stability of ascorbic acid was assessed after 60 days at 7 and 25 oC. Results indicated reductions in the range of 20 to 64% in the amounts of the minerals studied at the end of the DIS process, as compared to the amount found in fresh fruits, and negligible losses of vitamin C, except in the treatment with undiluted liquid invert sugar. Convective drying promoted losses of vitamin C in the range of 32 to 68%. The ranges of vitamin C loss in storage at 7 and 25 oC were 58 to 82% and 70 to 86%, respectively.

Desidratação por imersão-impregnação de abacaxi em soluções de sacarose e em xarope de açúcar invertido

This work consisted of evaluating the effect of the type of osmotic agent, degree of stirring, and temperature and concentration of the hypertonic solution on the kinetics of osmotic dehydration of sliced pineapple. The osmotic agents used here were sucrose in solutions with concentrations of 0.40, 0.44 and 0.47 g.mL-1, and undiluted inverted sugar syrup. Osmotic dehydration was carried out using a fruit to syrup weight ratio of 1:10, and employing two levels of temperature of the solutions, 40 and 50 °C, two shaking rates, 0 and 60 min-1, and a total immersion time of 2 hours. The results showed that immersion in undiluted inverted sugar caused a greater increase in the total soluble solids content in sliced fruit. The parameters characterizing the kinetics of osmotic dehydration showed higher values in the sliced fruit dehydrated in syrup at 40 to 50 °C under shaking.

Resistant starch content among several sorghum (Sorghum bicolor) genotypes and the effect of heat treatment on resistant starch retention in two genotypes.

The resistant starch (RS) contents in 49 sorghum genotypes and the effects of heat treatment using dry and wet heat on the grain and flour from two sorghum genotypes were investigated. The results showed a wide variation in the RS contents of the genotypes analyzed. The RS mean values were grouped into six distinct groups and ranged from 0.31±0.33 g/100 g to 65.66±5.46 g/100 g sorghum flour on dry basis. Dry heat causes minor losses in the RS content with retentions of up to 97.19±1.92% of this compound, whereas wet heat retained at most 6.98±0.43% of the RS. The SC 59 and (SSN76)FC6608 RED KAFIR BAZINE (ASA N23) cultivars, which have an average RS content of 65.51 g/100 g, were appropriate for human consumption, and the use of dry heat is presented as a better alternative for the preservation of RS in heat-treated grains.

Comparing sorghum and wheat whole grain breakfast cereals: Sensorial acceptance and bioactive compound content

The sensory acceptance and the content of bioactive compounds of whole-sorghum and whole-wheat breakfast cereals were compared. Sensory acceptance was assessed using the Food Action RatingScale. 3-Deoxyanthocyanidins, flavones and flavanones were determined by high-performance liquid chromatography (HPLC) with diode array detection, and vitamin E by HPLC with fluorescence detection. Total phenolics and antioxidant activity were determined by spectrophotometry. The sorghum breakfast cereal had better sensory acceptance (70.6%) than wheat breakfast cereal (41.18%). Sorghum had higher 3-deoxyanthocyanidin content (100% higher), total phenolic compounds (98.2% higher) and antioxidant activity (87.9% higher) than wheat breakfast cereal. Flavones and flavanones were not detected in both breakfast cereals. Total vitamin E content was 78.6% higher in wheat than in sorghum breakfast cereal. Thus, consumption of whole sorghum breakfast cereal should be encouraged, since it had good sensory acceptance and is a source of bioactive compounds that can promote benefits to human health.