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1.
J Food Sci ; 84(12): 3707-3716, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31665555

ABSTRACT

Products for consumers with special needs (celiac) and those who prefer a differentiated diet are necessary due to growing demand and a niche market to be exploited. The incorporation of other substances in the formulation of cakes requires a detailed analysis of their characteristics and sensorial attributes. However, the use of these flours may change the sensory characteristics of a product that is normally made from wheat flour. This study aimed to identify the ideal formulation of gluten- and lactose-free brownies made with rice flour and beans/lentils in consumer perception, through the combination of sensory tests. Using these data, the aim was to define recommendations for the reformulation of a product of high consumer acceptance, using easily accessible ingredients. The sensory methods used were descriptive analysis with a group of 20 trained evaluators and a group of 100 consumers evaluated through the check-all-that-apply and just-about-right questionnaire; all groups performed the acceptance test by hedonic scale. Data were analyzed using multivariate techniques and correlation matrices. The results showed that the attributes selected by the trained evaluators and consumers were sufficient to indicate that color and texture were the most striking characteristics that should be improved in brownie formulations without gluten and lactose. PRACTICAL APPLICATION: The study assumes that from the combination of sensory methods it is possible to verify the attributes that are most attractive to consumers in gluten-free and lactose-free cake formulations, using easily accessible ingredients that have technological, nutritional, and sensory quality, such as those formulated with wheat.


Subject(s)
Diet, Gluten-Free , Food Preferences/physiology , Food , Sensation/physiology , Consumer Behavior , Flour , Food Handling , Humans , Lactose
2.
J Food Biochem ; 43(7): e12900, 2019 07.
Article in English | MEDLINE | ID: mdl-31353740

ABSTRACT

The objective of this study was to evaluate the effects of grain moisture, temperature, and storage time on biochemical, digestibility, and technological parameters of carioca beans. The grains were stored at 16.7% and 13.8% of moisture at 12, 20, 28, and 36°C for 240 days. It was observed that a reduction in the storage temperature maintained the germination and vigor of the grains. The temperature of 36°C causes between 3.81% and 4.52% reduction in weight of a thousand grains and significant darkening. Carioca beans stored at 36°C exhibited hard-to-cook (HTC) defect at 80 days and increases in hardness after 240 days. The best digestibility indexes of carioca beans were obtained with refrigerated storage. The refrigerated storage (12°C) provides the best preservability of the grains throughout the storage, verified by the parameters biochemical, digestibility, and technological parameters. PRACTICAL APPLICATIONS: Carioca beans are among the most consumed beans in Brazil and their quality for consumption is directly influenced by storage conditions that alter color, nutritional value, bioactive, and cooking properties. Thus, this study seeks to present a practical and viable solution for stockist of bean grains, so that they can store these grains for long periods, maintaining the quality standards for commercialization. In addition, this technology allows the stockist to identify the best time for commercialization of the carioca beans, which has high added value.


Subject(s)
Food Storage , Phaseolus/chemistry , Seeds/chemistry , Antioxidants/metabolism , Cooking , Digestion , Germination , Nutritive Value , Phaseolus/physiology , Refrigeration , Seeds/physiology , Temperature , Time Factors
3.
Food Chem ; 286: 98-105, 2019 Jul 15.
Article in English | MEDLINE | ID: mdl-30827672

ABSTRACT

Three cooking temperatures (72, 80, and 88 °C) were applied to two rice genotypes (Puitá Inta CL and INOV CL) for preparing quick cooking brown rice. Samples were analyzed for cooking time, color, scanning electron microscopy (SEM), damaged grains, amylose, protein content and extractability, differential scanning calorimetry (DSC), X-ray diffraction (XRD), sensory properties, and in vitro digestion. Cooking time was reduced from 23.0-23.6 to 5.5-6.9 min when the highest temperature was applied, depending on genotype. The greatest grain deformation was observed for treatments from Puitá Inta CL. XRD showed greater ability of brown rice from Puitá Inta CL to gelatinize at 88 °C. Appearance, texture, and flavor of quick cooking brown rice prepared at 88 °C was inferior to its brown rice counterparts. Starch digestibility decreased by around 20-22% in 88 °C-prepared-quick cooking brown rice. Lower digestibility values were determined for 88 °C-treated-INOV CL, and were associated with grain integrity.


Subject(s)
Cooking/methods , Food Quality , Oryza/chemistry , Amylose/analysis , Amylose/chemistry , Calorimetry, Differential Scanning , Color , Digestion , Genotype , Humans , Microscopy, Electron, Scanning , Oryza/genetics , Plant Proteins, Dietary/analysis , Plant Proteins, Dietary/chemistry , Plant Proteins, Dietary/pharmacokinetics , Starch/pharmacokinetics , Taste , Temperature , X-Ray Diffraction
4.
Food Chem ; 274: 330-336, 2019 Feb 15.
Article in English | MEDLINE | ID: mdl-30372947

ABSTRACT

The present study aims to evaluate the physicochemical, rheological, and safety properties of starches isolated from maize kernels with different types of defects. Starch isolation showed to be a valuable alternative to defective yellow maize kernels, since the presence of the evaluated kernel defects (broken, fermented, rotten, moldy, germinated, insect-damaged, and shrunken and immature kernels) did not provide significant changes on starch purity and colour. Only starch isolated from shrunken and immature kernels exhibited reduced extractability. Starch obtained from germinated kernels exhibited the greatest solubility. While flour from moldy kernels showed 7.5 ppb of aflatoxin A1, 25.0 ppb of aflatoxin A2, and 1229.4 ppb of fumonisin B1, any of these mycotoxins were detected in isolated starch. In sum, minor changes in pasting, thermal, crystallinity, and morphological properties of the isolated starches from defective kernels were determined, which does not impair its use in industrial processes.


Subject(s)
Chemical Phenomena , Starch/chemistry , Zea mays/chemistry , Food Quality , Ointments , Rheology , Solubility , Temperature
5.
Food Chem ; 242: 37-44, 2018 Mar 01.
Article in English | MEDLINE | ID: mdl-29037703

ABSTRACT

The objective of this study was evaluate the effects of moisture and temperature during grain storage on the functional properties and isoflavone profile of soy protein concentrate. The protein concentrate was extracted from soybeans on the first day of storage and after 12months of storage, at 12 and 15% moisture and at temperatures of 11, 18, 25, and 32°C. The protein concentrate obtained from grains stored at 32°C showed decreased extraction yield (51.6% with 15% of moisture) and protein solubility (24.8% with 15% of moisture) with increased emulsifying capacity (52.2% with 12% of moisture) and foam formation, compared with sample obtained at the start of the storage period. The isoflavone profile showed a decrease in the concentrations of glycosylated, malonyl, and acetyl isoflavones and a corresponding increase in the concentrations of aglycone isoflavones, with the magnitude of these changes increasing with increasing storage temperature and moisture content.


Subject(s)
Glycine max/chemistry , Isoflavones/analysis , Soybean Proteins/chemistry , Edible Grain/chemistry , Food Storage , Solubility , Temperature
6.
Food Chem ; 242: 427-434, 2018 Mar 01.
Article in English | MEDLINE | ID: mdl-29037710

ABSTRACT

The changes in cooking quality and phenolic composition of whole black and red rice grains stored during six months at different temperatures were evaluated. Brown rice with known cooking quality properties and low phenolic levels was used for purposes comparison. All rice genotypes were stored at 13% moisture content at temperatures of 16, 24, 32, and 40°C. Cooking time, hardness, free and bound phenolics, anthocyanins, proanthocyanidins, and free radical scavenging capacity were analysed. The traditional rice with brown pericarp exhibited an increase in cooking time and free phenolics content, while rice with black pericarp exhibited a reduction in cooking time after six months of storage at the highest studied temperature of 40°C. There as increases in ferulic acid levels occurred as a function of storage temperature. Red pericarp rice grains showed decreased antioxidant capacity against ABTS radical for the soluble phenolic fraction with increased time and storage temperature.


Subject(s)
Cooking , Food Quality , Food Storage/methods , Oryza/chemistry , Phenols/analysis , Phenols/chemistry , Temperature , Color
7.
J Agric Food Chem ; 65(32): 6771-6778, 2017 Aug 16.
Article in English | MEDLINE | ID: mdl-28731694

ABSTRACT

The effects of the use of glyphosate (GLY), glyphosate plus carfentrazone (GLY/CAR), and paraquat (PAR) as plant desiccators on the technological and chemical properties of cowpea grains were investigated. All studied desiccants provided lower cooking time to freshly harvested cowpea. However, the coat color of PAR- and GLY/CAR-treated cowpea was reddish in comparison to the control treatment. Principal component analysis (PCA) from liquid chromatography-mass spectrometry (LC-MS) data sets showed a clear distinction among cowpea from the different treatments. Catechin-3-glucoside and epicatechin significantly contributed for discriminating GLY-treated cowpea, while citric acid was responsible for discriminating GLY/CAR-treated cowpea. Quercetin derivative and gluconic acid were responsible for discriminating control treatment. Residual glyphosate and paraquat content was higher than the maximum limits allowed by Codex Alimentarius and the European Union Commission. Improvements in the technological and chemical properties of cowpea may not be overlapped by the risks that those desiccants exhibit when exceeding the maximum limits of tolerance in food.


Subject(s)
Glycine/analogs & derivatives , Herbicides/pharmacology , Paraquat/pharmacology , Seeds/chemistry , Triazoles/pharmacology , Vigna/drug effects , Glycine/pharmacology , Seeds/drug effects , Vigna/chemistry , Glyphosate
8.
Food Chem ; 235: 51-57, 2017 Nov 15.
Article in English | MEDLINE | ID: mdl-28554646

ABSTRACT

Browning occurs in parboiled rice as a result of the Maillard reaction that negatively affects consumers' acceptability. The aim of this study was to evaluate the ability of gallic acid, glycine, reduced glutathione and l-cysteine at 0.1, 0.5, 1.0 and 2.0% levels to inhibit browning reactions during the parboiling of rice. Gallic acid and l-cysteine did not exhibit browning inhibition effect at the studied levels. On the other hand, glycine and the higher concentrations of reduced glutathione (1.0 and 2.0%) were able to promote a whiter color and a low free 5-hydroxymethyl-2-furaldehyde content (HMF). The highest level of 2.0% for glycine and reduced glutathione favored protein extractability and a weaker protein-starch matrix, roughly increasing the broken grains percentage. Cooking time changed just for reduced glutathione-treated rice, as a result of their weaker protein-starch matrix and the greater ability of the grains to soften during cooking.


Subject(s)
Cooking/methods , Oryza , Starch/analysis , Cysteine , Hot Temperature
9.
Food Chem ; 216: 194-200, 2017 Feb 01.
Article in English | MEDLINE | ID: mdl-27596409

ABSTRACT

The aim of this study was to evaluate the physicochemical, morphological, crystallinity, thermal, and pasting properties of starches isolated from rice grains with brown, black, and red pericarp. Starch was isolated from the rice grains at initial storage time, and after 6months of storage at different storage temperatures (16, 24, 32 and 40°C). Starch isolated from the grains stored for 6months at 40°C showed darker coloration, surface deformation of granules, and a significant reduction in the extraction yield, final viscosity, enthalpy, and crystallinity, independent of the grain pericarp coloration. The time and storage temperature not influence the swelling power and solubility of starch isolated from grains with brown pericarp, while for the grains with black and red pericarp there was reduction in swelling power and solubility of starches isolated of grains stored at 40°C. Grains stored at 16°C showed minimum changes in starch properties.


Subject(s)
Edible Grain/chemistry , Oryza/chemistry , Starch/chemistry , Food Storage , Solubility , Temperature , Viscosity
10.
J Food Sci ; 81(12): E2932-E2938, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27792845

ABSTRACT

The objective of this study was to evaluate the effects of starch source and amylose content on the expansion ratio, density, and texture of expanded extrudates, as well as to investigate the structural and molecular changes that occur in starch granules as a function of extrusion. The starches employed were rice starches (8%, 20%, and 32% amylose), carioca bean starch (35% amylose), and Hylon V® corn starch (55% amylose). The extrudates from rice starches containing 20% and 32% amylose exhibited the highest expansion ratio, while, extrudates from Hylon V® corn starch containing 55% amylose exhibited the lowest expansion ratio. The hardness values of the extrudates with 55% amylose were twice those of the extrudates with 20%, 32%, and 35% amylose. An additional finding was that although the amylopectin promoted the expansion of the gelatinized starch matrix, it failed to strengthen and sustain the walls of the extrudate bubbles during expansion.


Subject(s)
Amylopectin/analysis , Amylose/analysis , Fabaceae/chemistry , Oryza/chemistry , Starch/chemistry , Zea mays/chemistry , Food Analysis , Gelatin/chemistry , Molecular Structure
11.
Food Chem ; 208: 116-23, 2016 Oct 01.
Article in English | MEDLINE | ID: mdl-27132831

ABSTRACT

The effects of the type of solvolytic solution and number of extraction steps on the recovery of free phenolics, anthocyanins and proanthocyanidins from different rice samples were evaluated. Moreover, bound phenolic acids were determined as a function of enzymatic and/or alkaline hydrolysis treatment of the rice residue obtained after the extraction of free phenolics. The Acetone/Water (70:30 v/v) was the most effective solvolytic solution for extracting free phenolics from pigmented rice, as well as anthocyanins from black and wild rice, and proanthocyanidins from red rice. The application of three extraction steps increased the recovery of free phenolics up to 10%. The adoption of an enzymatic treatment, with α-amylase in order to reduce the paste viscosity of the residue, increased the extractability of bound phenolics. α-Amylase at 37°C during 15min followed by an alkaline hydrolysis at 37°C was the best treatment for the recovery of bound phenolics.


Subject(s)
Hydroxybenzoates/analysis , Oryza/chemistry , Phenols/analysis , Plant Extracts/chemistry , Anthocyanins/analysis , Hydrolysis , Proanthocyanidins/analysis
12.
J Food Sci ; 81(3): H762-8, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26816290

ABSTRACT

Soybean is a rich source of bioactive compounds, such as phenolic acids, flavonoids, isoflavones, carotenoids, and tocopherols. The amount of bioactive compounds in freshly harvested soybeans and their derived products has been determined; however, when they are used in the food industry, soybeans are generally stored prior to being processed. This study aimed to evaluate the effects of soybean moisture content (12%, 15%, and 18%) and storage temperature (11, 18, 25, and 32 °C) on the free phenolic, total flavonoid, vanillic acid, total carotenoid, and δ- and γ-tocopherol content of soybeans stored for 12 mo. Moreover, the ABTS and DPPH radical scavenging activities of phenolic extracts were determined. There was an increase in free phenolics and total flavonoids in the stored grains compared with the grains on the 1st d of storage. Vanillic acid showed a decrease in soybeans stored at 15% and 18% moisture content and 25 or 32 °C, which indicated some degradation into other metabolites. Total carotenoid content decreased as a function of storage temperature and showed some temperature-dependent degradation. The δ- and γ-tocopherol content also tended to decrease in grains stored at 15% or 18% moisture content or 25 or 32 °C, regardless of the moisture content studied.


Subject(s)
Antioxidants/pharmacology , Food Storage , Glycine max/chemistry , Seeds/chemistry , Temperature , Water , Antioxidants/analysis , Benzothiazoles/metabolism , Biphenyl Compounds/metabolism , Carotenoids/analysis , Carotenoids/pharmacology , Edible Grain/chemistry , Flavonoids/analysis , Flavonoids/pharmacology , Food-Processing Industry , Humans , Hydroxybenzoates/analysis , Hydroxybenzoates/pharmacology , Isoflavones/analysis , Isoflavones/pharmacology , Phenols/analysis , Phenols/pharmacology , Picrates/metabolism , Sulfonic Acids/metabolism , gamma-Tocopherol/analysis , gamma-Tocopherol/pharmacology
13.
Food Chem ; 191: 105-12, 2016 Jan 15.
Article in English | MEDLINE | ID: mdl-26258708

ABSTRACT

This study aims to evaluate the effects of polishing and parboiling on proximate composition, structure, phenolic compounds, antioxidant activity, cooking time and hardness of IAC-600 black rice cultivar and MPB-10 red rice lineage. Proximate analysis and light micrographs revealed higher migration of red rice proteins than black rice proteins to the endosperm as a result of parboiling. Parboiling reduced the ash content of red rice while no difference was determined in black rice. Gelatinized starch granules from both genotypes showed similar appearance. There was a decrease in relative crystallinity on both black and red rice subjected to parboiling, which was an indicative of crystallites disruption. Polishing removed more than 90% of free phenolics for both genotypes, while parboiling allowed the partial preservation of free phenolics content in polished rice. Parboiling induced an increase in the cooking time of red rice, but a decrease in the cooking time of black rice.


Subject(s)
Cooking , Oryza/chemistry , Color , Genotype , Hardness , Hot Temperature , Oryza/genetics , Phenols/analysis , Starch/chemistry
14.
Carbohydr Polym ; 133: 46-51, 2015 Nov 20.
Article in English | MEDLINE | ID: mdl-26344253

ABSTRACT

The quality of sorghum grains can vary according to the conditions of the drying temperature and storage time. The objective of this study was to evaluate the effects of the drying temperature and storage time of sorghum grain on the structure and technological properties of starch. The sorghum grains were dried at 45, 65, and 85°C and stored for six months. The grains were stored in an environment with a controlled temperature and humidity, and the starch from sorghum grains was isolated in initial time, after three and six months. The sorghum starches grains dried at 45 and 65°C present higher relative crystallinity than the starches of sorghum grains dried at 85°C in three months of storage. A reduction in the solubility of the starches of the sorghum grains dried at 85°C was observed when the grains were stored during six months. The breakdown and swelling power of the starches were reduced with the increase of the drying temperature.


Subject(s)
Desiccation , Food Storage/methods , Sorghum/chemistry , Starch/chemistry , Temperature , Plant Proteins/analysis , Solubility , Time Factors
15.
Plant Foods Hum Nutr ; 70(4): 463-9, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26249219

ABSTRACT

The characteristics of modern life has led consumers to seek convenience and speed in food preparation, but storage, which is often prolonged, can result in grain hardening, leading to higher energy consumption during preparation, grain with increased hardness is often discarded. Due to the increasing global demand for grain, the use of alternative techniques aimed at reducing grain waste is necessary. Therefore, we studied a method that meets consumer demand and results in better use of harvested grain. The beans studied were cowpea beans (Vigna unguiculata) of the BRS Guariba cultivar after 1 and 12 months of storage. Sodium chloride (NaCl), potassium chloride (KCl) and sodium bicarbonate (NaHCO3) were added to soaking water at different concentrations as a way to reduce cooking time. These beans were placed in soaking water for 12 h at 3 concentrations (0, 1.0 and 2.5%). The cowpeas soaked in water containing NaHCO3 presented the highest hydration coefficient, which increased with the salt concentration; these beans also had decreased hardness, chewiness and cooking time.


Subject(s)
Fabaceae , Food Handling/methods , Salts , Water , Chemical Phenomena , Hardness , Hot Temperature , Potassium Chloride , Sodium Bicarbonate , Sodium Chloride , Time Factors
16.
Ciênc. rural ; 44(8): 1377-1383, 08/2014. tab, graf
Article in Portuguese | LILACS | ID: lil-721431

ABSTRACT

Os tratamentos fitossanitários na cultura do arroz irrigado geralmente são realizados via aplicação aérea. Por isso, o trabalho objetivou avaliar a produtividade, qualidade do grão e incidência de doenças em arroz da cultivar 'Puitá Inta CL' através da aplicação dos fungicidas Azoxistrobina e Difenoconazol com bicos defletores, 20 e 30L ha-1, bicos cônicos 20 e 30L ha-1 e atomizadores rotativos de disco 10 e 15L ha-1. Os tratamentos realizados com atomizador rotativo de disco 10L ha-1 e bico cônico 30L ha-1, receberam uma segunda aplicação 15 dias após. Os parâmetros avaliados foram os níveis de doenças foliares, peso de mil grãos, número de grãos por panícula, patologia de sementes, renda e rendimento. Não se verificou nenhuma diferença entre os tratamentos em nível de campo, entretanto, as avaliações pós-colheita revelaram importante controle dos fungos Fusarium sp., Gerlachia sp. e Bipolaris sp.


Phytossanitary treatment on irrigated rice are usually done by aerial application. In face of that, the aim of this project was to evaluate yield, grain quality and disease in rice CV Puitá Inta CL through the fungicide Azoxystrobin+difenoconazole application with 20 and 30L ha-1 using deflecting nozzles, 20 and 30L ha-1, tapered nozzles with 20 and 30L ha-1 as well as rotary atomizers disk with 10 and 15L ha-1. The plots sprayed with rotary atomizer disk using 10L ha-1 and tapered nozzles using 30L ha-1, received a second application15 days later. The evaluated parameter were leaves disease control, yield, income and grain pathology. There were no differences detected between treatments in the field, however, the assessments revealed important post harvest control of Fusarium sp., Gerlachia sp. and Bipolaris sp.

17.
J Food Sci ; 79(7): E1351-8, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24894499

ABSTRACT

UNLABELLED: Soybeans were hydrothermally treated at 2 different temperatures (40 °C and 60 °C) and for 4 different hydration times (4, 8, 12, and 16 h) to (i) increase the isoflavone aglycone content in a soy protein isolate and (ii) evaluate the changes in thermal, functional, and structural properties of a soy protein isolate as a function of hydrothermal treatment conditions. Our study is the first to evaluate aglycone content, extraction yield, ß-glucosidase activity, differential scanning calorimetry, protein digestibility, scanning electron microscopy, water absorption capacity (WAC), foaming capacity (FC), and foaming stability of soy protein isolates prepared from hydrothermally treated soybeans. For aglycone enhancement and the extraction yield maintenance of soy protein isolates, the condition of 40 °C for 12 h was the best soybean hydrothermal treatment. The structural rearrangement of proteins that occurred with the hydrothermal treatment most likely promoted the capacity of proteins to bind to aglycone. Moreover, the structure shape and size of soy protein isolates verified by scanning electron microscopy appears to be related to the formation of hydrophobic surfaces and hydrophobic zones at 40 °C and 60 °C, respectively, affecting the protein digestibility, WAC, and FC of soy protein isolates. PRACTICAL APPLICATION: The aglycone content in the soy protein isolate can be improved with the hydrothermal treatment of soybeans. The temperature and time used for hydrothermal treatment must be selected in order to achieve a soy protein isolate with high aglycone content, extraction yield, and functionality. This technology is suitable for providing healthier soy protein isolates for food industry with improved functional and structural properties.


Subject(s)
Glycine max/chemistry , Isoflavones/analysis , Soybean Proteins/chemistry , Temperature , Water
18.
Ciênc. rural ; 44(5): 931-936, maio 2014. tab
Article in Portuguese | LILACS | ID: lil-707029

ABSTRACT

A aveia destaca-se dentre os cereais por seu teor e qualidade proteica, alta porcentagem de lipídios distribuídos por todo o grão e predominância de ácidos graxos insaturados, além de possuir altos teores de fibra alimentar, minerais e antioxidantes, responsáveis pelos efeitos benéficos à saúde humana. Devido aos seus constituintes, a aveia apresenta forte tendência à rancidez e, por esse motivo, faz-se necessária a inativação enzimática das cariopses. Na indústria, a inativação normalmente é realizada pelo tratamento hidrotérmico. Objetivou-se, com este trabalho, estudar os efeitos do processamento hidrotérmico em escala industrial sobre parâmetros de composição química, atividade enzimática, β-glicanas e compostos fenólicos solúveis totais nas frações de aveia farinha, farelo e integral. O processamento industrial da aveia foi realizado em batelada com temperatura e pressão constantes e tempo de retenção na coluna de 37min e 110min. O experimento foi conduzido em delineamento inteiramente casualizado, sendo os resultados submetidos à análise de variância e as médias comparadas pelo teste Tukey a 5% de significância. Os constituintes químicos das frações farinha, farelo e integral foram pouco afetados nos tempos de retenção estudados. O tempo de retenção de 37min se mostra mais adequado por ser suficiente para inativar as enzimas lipase e peroxidase e preservar os compostos fenólicos solúveis totais em todas as frações de aveia estudadas.


Oat stands out among other cereals because of its quality as high protein content, high percentage of lipids distributed throughout the grain and predominance of unsaturated fatty acids, in addition oat presents high contents of dietary fiber, minerals and antioxidants responsible for the beneficial effects to human health. Due to their constituents oats has a strong tendency to rancidity and because of this reason is necessary to enzymatic inactivation of caryopses. In industry, the inactivation is carried out usually by hydrothermal treatment. The objective of this work was to study the effects of hydrothermal processing on an industrial scale. Parameters of chemical composition, enzyme stability, β-glucan and total soluble phenolic compounds oat fractions (flour, bran and wholemeal) were evaluated. The industrial processing was carried out in batch with constant temperature and pressure and column retention time of 37min and 110min. The experiment was conducted in a completely randomized design and the results were submitted to analysis of variance and means were compared by Tukey test at 5% significance. The chemical constituents of the fractions flour, bran and whole were little affected the retention times studied. The retention time of 37min shown more appropriate for being sufficient to inactivate lipase and peroxidase enzymes and preserve the phenolic total soluble in all oats fractions studied.

19.
Carbohydr Polym ; 102: 88-94, 2014 Feb 15.
Article in English | MEDLINE | ID: mdl-24507259

ABSTRACT

Considering the importance of maize starch and the lack of knowledge about the effects of storage temperature on the isolated starch properties; maize grains were stored during 12 months at different temperatures (5, 15, 25 and 35 °C). The extraction yield and the physicochemical, thermal, pasting, crystallinity and morphological properties of starches were determined. The starch isolated from grains stored at 35 °C was yellowish and showed a 22.1% decrease in starch extraction yield compared to freshly harvested maize grains. At 35 °C, a reduction in crystallinity was observed by the end of 12 months, despite a parallel rearrangement of the starch chains which resulted in an increase in X-ray peak intensities, gelatinisation temperatures and enthalpy. The starch isolated from maize grains stored at 35 °C appears to have smaller granules, which presents some points in their surface, potentially attributed to the protein matrix compressing the granules within maize grains.


Subject(s)
Starch/isolation & purification , Temperature , Zea mays/chemistry , Calorimetry, Differential Scanning , Color , Crystallography, X-Ray , Microscopy, Electron, Scanning , Solubility
20.
J Sci Food Agric ; 93(9): 2331-7, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23423960

ABSTRACT

BACKGROUND: Few studies on starch modifications using different chemical agents are available in the literature, and no reports were found on the combined effect of oxidation and alkaline treatment of corn starch. Thus this work evaluated the physicochemical, pasting, morphological, cystallinity and thermal properties of chemically modified corn starch, after either the isolated or combined action of alkaline (sodium hydroxide) and oxidative (sodium hypochlorite) treatments. RESULTS: The highest values for the sum of carbonyl and carboxyl and enzymatic hydrolysis occurred in starches submitted to oxidative treatment at high active chlorine concentrations. The alkali treatment in isolation modified the pasting properties, reduced the paste temperature and increased the peak viscosity, breakdown, final viscosity and setback of starches. Starch modified by the action of sodium hypochlorite and hydroxide in combination presented more severe damage on granule surfaces. CONCLUSION: The results show that corn starch modified by the combined action of oxidative and alkaline treatments should be studied more, especially at the concentration limit of sodium hydroxide where gelatinization occurs. Under these conditions the effect of oxidation can be more intense and thus allow the production of starches with different properties and an increase in their industrial applications.


Subject(s)
Caustics/chemistry , Food Handling , Oxidants/chemistry , Seeds/chemistry , Starch/chemistry , Zea mays/chemistry , Chemical Phenomena , Crystallization , Gels , Hot Temperature , Hydrolysis , Microscopy, Electron, Scanning , Osmolar Concentration , Oxidation-Reduction , Sodium Hydroxide/chemistry , Sodium Hypochlorite/chemistry , Starch/ultrastructure , Suspensions , Transition Temperature , Viscosity
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