Cesar Francisco Ciacco

Composition and Functional Properties of Banana Flour from Different Varieties

The chemical composition and some physico-chemical characteristics of the flour obtained from eight different banana varieties are presented. The flour was prepared by freeze-drying a homogenate of green banana pulp. Amylose, starch, dietary fiber, protein, ash, moisture and lipid contents were determined. Viscosity and gelatinization of starch were also investigated. Banana flour is rich in starch granules. Peak temperature of gelatinization varied from 68 to 76 °C according to the variety. All of them showed an increase in viscosity during cooling but the variety Ouro colatina showed more stability during shearing and cooling. Chemical composition of the flour also varied according to the variety. The range obtained were 61—76.5% starch, 19—23% amylose, 2.5—3.3% protein, 4—6% moisture, 0.3—0.8% lipids, 2.6—3.5% ashes, and 6—15.5% total fiber. Considering that the flour production is easier and faster than the isolation of the starch, it would be not only more practical but also less expensive to use the flour instead.

The structure of waxy corn starch: Effect of granule size

The granules of waxy corn starch were isolated and various samples were separated by size and classified according to their average diameter in: non-separated granules (N), granules with diamcter < 15 μm (S) and granules with diameter ≥ 15 μm (L). The samples were hydrolyzed by bacterial α-amylase and fungal amyloglucosidase. The starch granules remaining after enzymatic hydrolysis were analysed by X-ray diffraction and optical and scanning electron microscopy. Sephadex G-50 gel permeation chromatography of the dissolved residues from the hydrolysis of the N and S samples was performed directly and after successive enzymatic digestion with pullulanase and β-amylase. The results showed that the percentage of hydrolysis increased with a decrease in diameter. No apparent differences in waxy corn starch when observed under light and scanning electronic microscope were observed, regardless of diameter and enzyme action, although both large and small granules showed extensive surface corrosion after enzymatic attack. X-ray analysis suggested a decrease in the quantity of crystalline areas in the smaller granules, which would explain the high percentage of hydrolysis evidenced by these granules. The elution patterns of the α-glucans of both starches (N and S) were similar and reveled the presence of two fractions which were not susceptible to α-amylase and amyloglucosidase attack suggesting that these fractions were involved in the waxy corn starch crystalline regions. Debranching with pullulanase followed by gel-permeation chromatography showed that the amylopectins from the starch granules studied contained three groups of unit chains instead of the two reported in the literature.

OCORRÊNCIA E CARACTERIZAÇÃO DO AMIDO RESISTENTE EM AMIDOS DE MILHO E DE BANANA

In this work the occurrence of resistant starch (RS) in normal corn and banana (naturally resistant) starches was studied and also the effects of conditioning moisture, storage temperature and time on the formation of RS in normal corn starch. The physico-chemical characteristics of the RS from corn and banana were also studied, including the molecular structure. The proximate composition data showed that the percentage of RS is not related to the chemical composition of the granule. Banana starch showed granules with a certain polyformism, and a B x-ray diffraction pattern. The dextrins from this starch showed a linear fraction with DP 34 resistant to sequential action of b-amylase and/or pulullonase. The pasting characteristics indicated that the high RS content observed in this starch, could not be explained by the physical structure which maintains the granule. The normal corn starch showed polyhedral shapes. Exclusion gel chromatography of the residues obtained after b- amylase and/or pulullonase hydrolysis, did not show a fraction with DP 34, although the pasting properties indicated a higher granule cohesivity than that of the banana starch. The hydrothermal treatment almost triplicated the RS content (7.15%) of the corn starch, because of the formation of more cohesive structures inside the granule. The retrograded corn starch, with 7.15% RS, was constituted of porous fragments and a C type diffraction pattern. On the other hand, the non significance of storage time on the formation of RS in conjunction with the absence of a fraction with DP 34, suggested the participation of amylose in this resistant structure.

Efeitos da precipitação pluvial, da umidade relativa do ar e de excesso e déficit hídrico do solo no peso do hectolitro, no peso de mil grãos e no rendimento de grãos de trigo

About 90% of the wheat production in Brazil is located in Parana, Rio Grande do Sul and Santa Catarina states. In these states there is a considerable climatic variability and consequently wheat production becomes a risky activity. Therefore, the decrease of wheat production and grain yield has been analyzed by a great number of investigators. This work aimed to verify the influence of rainfall, relative humidity, and water excess and deficit on test weight, thousand kernel weight, and grain yield of wheat. Data of Embrapa 16 wheat cultivar, obtained during the 1990-98 period, in seven Rio Grande do Sul state locations, and in four in Santa Catarina were used. Statistical analysis used was multiple correlation. It was verified that: a) rainfall and water excess in soil affected negative test weight, thousand kernel weight, and grain yield of wheat, and relative humidity influenced positively as much as negatively such variables; b) soil water deficit affected positive test weight, thousand kernel weight, and the grain yield of wheat after the physiological maturation, that is, during the first ten days previous to the harvest of the crop, and negative for the other periods.

Função dos ingredientes na consistência da massa e nas características do pão de queijo

O processo de fabricacao de pao de queijo envolve basicamente escaldamento do polvilho com leite, agua e oleo, amassamento com ovo, adicao de queijo e assamento. Este trabalho teve como objetivo estudar a funcao dos ingredientes na consistencia da massa e nas caracteristicas dos paes de queijo produzidos. As massas foram obtidas de 100% polvilho azedo (PA), 100% polvilho doce (PD), 70% polvilho azedo + 30% polvilho doce (PS) e 50% polvilho azedo + 50% polvilho doce (PC), combinados com formulacoes: completa, com todos os ingredientes (FC), sem leite, mas com agua (SL), sem ovo (SO) e sem queijo. As massas foram desenvolvidas no Farinografo Brabender, o qual teve deste modo sua forma de utilizacao ampliada, e a evolucao da consistencia destas massas foi acompanhada por meio dos graficos gerados. As massas foram moldadas e assadas e as caracteristicas dos paes analisadas. Durante o escaldamento e mistura houve elevacao dos valores de consistencia, o ovo causou queda drastica desta consistencia e o queijo provocou nova elevacao, tornando a massa moldavel. A consistencia das massas foi mais afetada pelas formulacoes sendo que, as sem leite (SL) apresentaram os maiores registros; as sem queijo (SQ) as menos consistentes. As massas sem ovo (SO) apresentaram-se secas, duras, despedacando-se quando manuseadas. Paes de queijo FC e SQ apresentaram maior volume especifico e maior diâmetro. Paes de queijo SO apresentaram menor indice de expansao. O ovo e o queijo desempenharam importante papel na obtencao de massas facilmente moldaveis, originando paes de queijo com boas caracteristicas estruturais.

Avaliação do efeito de variáveis meteorológicas na qualidade industrial e no rendimento de grãos de trigo pelo emprego de análise de componentes principais

A qualidade industrial de trigo, alem de ser afetada pelo genotipo, tambem e influenciada por fatores ambientes, como as condicoes meteorologicas prevalecentes durante a permanencia da cultura na lavoura. Este trabalho teve por objetivo verificar a influencia de variaveis meteorologicas, bem como do deficit e do excesso hidrico do solo, no peso do hectolitro (PH), no peso de mil graos (PMG), na extracao experimental de farinha (EXT), na forca geral de gluten (W), na relacao P/L (P/L), na microssedimentacao com dodecil sulfato de sodio (SDS) e no numero de queda (NQ). Foram usados dados de experimentos com trigo EMBRAPA 16, conduzidos nos anos de 1990 a 1998, em sete locais do Rio Grande do Sul e em quatro locais de Santa Catarina. A analise estatistica realizada foi de componentes principais. Verificou-se que: a) a precipitacao pluvial, a umidade relativa do ar e o excesso hidrico do solo influenciaram negativamente o PH, o PMG, o NQ, a P/L e o rendimento de graos. O W, a EXT e a SDS foram afetados positiva e negativamente por essas variaveis, dependendo do periodo de avaliacao estudado; b) a temperatura minima influenciou positivamente a EXT, o W e a SDS. Para as demais variaveis, quando ocorreu influencia da temperatura minima, esta foi negativa; c) a temperatura media associou-se negativamente com o PH, com o PMG, com o NQ e com o rendimento de graos e positivamente com a EXT e com o W. Para a P/L e para a SDS, a temperatura media afetou tanto positiva quanto negativamente; d) a temperatura maxima correlacionou-se negativamente com o rendimento de graos e positivamente com a EXT. O W, a SDS e a P/L apresentaram periodos de correlacao positivos e negativos com a temperatura maxima; e e) a radiacao solar global influenciou positivamente todas as caracteristicas estudadas, exceto a SDS.

Distribution of aflatoxin contamination in maize samples

The distribution of the aflatoxin contamination was studied among four maize fractions, separated according to Brazilian grading rules for maize. The fraction that contained fermented, moldy, heated and sprouted grains normally had the highest levels of aflatoxin. However, the fraction contribution to the whole sample contamination level took into account the contamination fraction level and its weight to the whole sample. Considering this, the fraction that contained insect damaged, hollow, up to ¼ fermented and grains damaged by other causes was normally the fraction responsible for the total contamination level in the samples. Nevertheless, the fraction contributions were variable from sample to sample. Therefore, in conclusion, it was not possible to establish a standard behavior for grain fraction-type contribution for different maize lots. The Brazilian grading by qualitative types applied to samples did not show statistic correlation with aflatoxin contamination levels (P<0.05). Two type-1 samples (the best quality type) presented contamination of 380 and 146ng/g. The number of samples with contamination levels above those allowed by Brazilian law (20ng/g) was the same for qualitative types 2, 3, and BS (Below Standard).

Fracionamento do grão de Amaranthus cruentus brasileiro por moagem e suas características composicionais

Grain amaranth is normally consumed whole. The effect of milling on the chemical and nutritional composition, stability to oxidation and color of the flours of the Brazilian grain amaranth (Amaranthus cruentus) has been assessed. Grains of the cv Japonica were pre-conditioned to moistures from 9.2 to 13.7% and fractionated in a cereal mill. Increasing the moisture resulted in a pronounced decrease of flour yield from 39 to 14%. The refined flour (break and reduction fractions combined) of the 9.2% moisture grain showed a total protein content of 13.9%, against the 16.2% of the whole flour, whereas the total lipid content fell from 6.78 to 6.11% with no detectable change in oxidative stability after refining. The fiber content was reduced slightly, from 4.6 to 3.8% for the highest and the lowest moisture contents, respectively, while the lighter color attribute of the flour increased with processing. It is concluded that in spite of the better appearance and high protein content of the refined flour, milling of grain amaranth will result in low yields and that refining will not remove any substantial amounts of oil that would guarantee higher oxidation stability to the flour.

Production of ethanol from extruded degermed corn grits by a nonconventional fermentation method

Abstract Degermed corn grits (DCG) were extruded at 150°C, with a compression rate of 1 : 2, and the materials were fermented by a nonconventional fermentation method. Yields of ethanol from various concentrations (12–30 g/200 ml) of extruded DCG were 0.37–0.38. It was found that the mold brad enzyme was superior to the glucoamylase preparations for ethanol fermentation, but combinedenzyme systems such as a mixture of glucoamylase, acid protease, and cellulolytic enzymes are as efficient in converting the extruded DCG to ethanol as the mold bran enzyme alone.

Production of ethanol from extruded corn starch by a nonconvencional fermentation method

SummaryIn single-step 48-hour fermentations of extruded, liquefied and raw corn starch, the yields of ethanol from extruded starch were similar to those from liquefied starch, whereas the yields of ethanol from raw starch were lower.