Effect of packaging materials and storage conditions on the microbial quality of pearl millet sourdough bread.

Sourdough is one of the oldest methods of cereal fermentation applied mainly for the sole purpose of baking and has been proven to enhance the production of microbiologically safe products. This study investigated the effect of packaging materials and storage conditions on the microbial quality and some intrinsic parameters of the sourdough bread. Pearl millet flour was naturally fermented for 72 h to obtain sourdough which was used with pearl millet flour to produce sourdough bread while the control bread was produced with pearl millet flour and yeast. The bread samples were packaged in low density polyethylene and aluminium foil and stored at -5, 4, 6, 28 and 37 °C. The total bacteria count (log cfu/g) and total fungal count (spore/g) increased with an increase in storage temperature and storage days. Fungi colonies isolated from stored bread samples include species of Rhizopus, Aspergillus, Penicillium and Mucor. A significant increase (p ≤ 0.05) in the pH and decrease in the moisture content of the bread samples were observed as storage period and storage temperature increased. Sourdough fermentation improved the microbial qualities and extended the shelf life of bread.

Chitosan-based nanocomposite films with carnauba wax, rosin resin, and zinc oxide nanoparticles.

This work aimed to develop edible emulsion-based barriers in the form of chitosan composite films, with a focus on assessing the impacts of carnauba wax, rosin resin, and zinc oxide nanoparticles on their properties. Six films were produced by casting using chitosan as polymer base and glycerol as plasticizer. Acetic acid and polysorbate 80 were also used to facilitate the dissolution and mixing of the components. The six filmogenic solutions contained chitosan at 1.2% w/v, wax or resin content with 0 or 0.6% m/v and ZnO with 0 or 0.05% m/v. The dried films were characterized according to their chemical, barrier, mechanical, thermal and optical properties. All treatments resulted in flexible films. Chitosan films appeared smoother and more uniform under SEM imaging, while carnauba wax films displayed roughness due to their hydrophobic nature. Wax and resin films were less transparent and water soluble than the chitosan-only films. On the other hand, the addition of ZnO in the formulations increased the solubility of the films. The sorption degree was in line with the solubility results, i.e., films with ZnO presented higher sorption degree and solubility values. All treatments showed low or non-light UV transmission, indicating that the films provide good barrier to UV light. In the visible light region, films of resin with ZnO showed the lowest transmittance values, hence offering a good barrier to visible light. Among the evaluated films, chitosan, and resin films with ZnO nanoparticles were more rigid and resistant to deformation. Overall, films produced with rosin resin and ZnO nanoparticles showed potential improvements in barrier, mechanical, thermal, and optical properties, mainly due to their low water solubility, good UV protection and low permeability to water vapor and oxygen, which are suitable for using in formulations, intended to produce edible films and coatings.

Synthesis and characterization of new dialkylacylphosphonylhydrazones.

The present work refers to the synthesis of novel dialkylacylphosphonylhydrazones that occurs in three reaction steps: the first one is the synthesis of different dialkyl acetate phosphonoacetates obtained by the reaction of ethyl bromoacetate with the trialkyl phosphite of interest. The second one is the synthesis of acetic diethoxyphosphonylhydrazines which is from the reaction between the synthesized dialkyl phosphonoacetates and hydrazine. The third and final steps is the condensation of acetic diethoxyphosphonylhydrazides with different heterocyclic aldehydes. In total, 17 unpublished compounds, namely 1 to 17 (Table 1) were obtained with a diastereoisomeric mixture of the preferential conformation E and all the compounds were characterized by 1-H and 13-C and 31-P NMR, infrared (IR) and mass spectroscopy (MS). This work presents the characterization data of these compounds.

Carotenoids, sugars, ascorbic acid, total phenolics, and antioxidant activity of murici from Brazilian Cerrado during refrigerated storage / Carotenoides, açúcares, ácido ascórbico, fenólicos totais e atividade antioxidante de murici do Cerrado brasileiro durante armazenamento refrigerado

ABSTRACT: Native fruits are economically important to small producers, and they are a important part of the diet of several communities. Therefore, postharvest studies of these fruits are essential. In addition, research involving their chemical composition can identify substances that add potential value to the fruits, especially from a nutritional and medicinal standpoint. This study characterized the fruits of the muricizeiro shrub (Byrsonima crassifolia, Malpighiaceae), which were harvested from native plants on private properties and stored for 16 days at a mean temperature of 12 °C. The fruits were evaluated during storage for: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ascorbic acid content, phenolics and carotenoids total, carotenoids profile, glucose, fructose and sucrose contents. Overall, the temperature that the fruits were storage at was effective at maintaining the quality of the fruit. However, the ascorbic acid content of the fruits did decrease during the storage period. Results showed that the fruits had a high antioxidant capacity, possibly because of the presence of phenolic compounds and carotenoids. It is also important to highlight that this fruit is source of vitamin A, owing to the high concentration of β-carotene.

RESUMO: Frutas nativas são economicamente importantes para pequenos produtores, e são uma parte importante da dieta de várias comunidades. Portanto, estudos pós-colheita desses frutos são essenciais. Além disso, pesquisas envolvendo sua composição química podem identificar substâncias que agregam valor potencial às frutas, principalmente do ponto de vista nutricional e medicinal. Este estudo caracterizou os frutos do arbusto muricizeiro (Byrsonima crassifolia, Malpighiaceae), que foram colhidos de plantas nativas em propriedades particulares e armazenados por 16 dias em temperatura média de 12 °C. Os frutos foram avaliados durante o armazenamento em vista da: atividade de eliminação de radicais 2,2-difenil-1-picril-hidrazil (DPPH), conteúdo de ácido ascórbico, fenólicos e carotenoides totais, perfil de carotenoides, conteúdo de glicose, frutose e sacarose. No geral, a temperatura em que os frutos foram armazenados foi eficaz para manter a qualidade do fruto. No entanto, o teor de ácido ascórbico dos frutos diminuiu durante o período de armazenamento. Os resultados mostraram que os frutos apresentaram alta capacidade antioxidante, possivelmente pela presença de compostos fenólicos e carotenoides. Também é importante destacar que esta fruta é fonte de vitamina A, devido à alta concentração de β-caroteno.

Conservação pós-colheita de espigas de milho verde minimamente processado sob diferentes temperaturas / Post-harvest conservation of fresh-cut corn on the cob (Zea maiz L. ) under different temperatures

Objetivou-se, neste trabalho, avaliar o efeito de três temperaturas (5ºC, 8ºC e 11ºC), na qualidade de híbridos de milho verde (Zea maiz L.) com endosperma normal, minimamente processado, durante oito dias de armazenamento, com avaliações a cada dois dias. Foram utilizadas espigas de dois híbridos, sendo um comercial da Sementes Agroceres (Ag 1051) e outro do programa de melhoramento da Embrapa Milho e Sorgo (Embrapa HT1). A temperatura de 5ºC foi a que melhor preservou a qualidade das espigas dos híbridos de milho verde estudados, por proporcionar perda de massa reduzida e manutenção dos teores de sólidos solúveis, frutose e glicose. O híbrido Ag 1051 apresentou menor perda de massa, maiores valores de umidade e maior teor de frutose. O Embrapa HT1 apresentou maiores valores iniciais e finais para os teores de sólidos solúveis e maior valor para a coloração b*. O valor L*, que indica quãoclaro e escuro é produto, também diminuiu ao longo do armazenamento, indicando escurecimento das espigas ao longo do armazenamento.

This work had the aim of evaluating the effect of three temperatures (5ºC, 8ºC and 11ºC) on the quality of fresh-cut corn on the cob (Zea maiz L.) with normal endosperm, for 8 days, with analyses taken every two days. Corn on the cob of two hybrids was used, a commercial common type from Sementes Agroceres (Ag 1051) and the other from the breeding program Embrapa Milho e Sorgo (Embrapa HT1). The temperature of 5ºC was more efficient to preserve the quality of normal corn by promoting reduced mass loss and higher contents of soluble solids, fructose and glucose. The hybrid Ag 1051 presented lower mass loss, higher contents of moisture and higher content of fructose. The hybrid Embrapa HT1 presented higher initial and final values for soluble solids and higher b* value. The L* value also decreased along storage, indicating browning of the corns along the storage.