Advantages of a combined method of decalcification compared to EDTA

Decalcification of mineralized tissues is an essential step during tissue processing in the routine histopathology. The time required for complete decalcification, and the effect of decalcifier on cellular and tissue morphology are important parameters which influence the selection of decalcifying agents. In this study, we compared a decalcifying solution (ETDA) composed of both acid and chelating agents to a classical and well‐known decalcifying agent (EDTA). To this purpose, the optic density of bone radiographs, residual calcium analysis, bone sample weight, and histological and immunohistochemical analysis were performed. Our data suggest that, similarly to EDTA, the ETDA solution completely removes the calcium ions from the samples enabling easy sectioning. However, unlike the EDTA, this agent takes much less time. Furthermore, both agents showed comparable decalcification efficacy, and similarly, they did not produce cellular, tissue or antigenicity impairments. Therefore, ETDA may be a suitable option when it is necessary an association between a rapid and complete removal of calcium minerals, and a suitable preservation of structure and antigenicity of tissues. Microsc. Res. Tech. 78:111–118, 2015. © 2014 Wiley Periodicals, Inc.     

Acidified sodium chlorite as an alternative to chlorine to control microbial growth on shredded carrots while maintaining quality

Shredded carrots are particularly susceptible to microbial growth and quality deterioration as a result of a large cut surface area to mass ratio. Acidified sodium chlorite (ASC) in the concentration range 500–1200 µL L^?1 has been shown to have stronger efficacy against pathogens and spoilage bacteria than chlorine and does not form carcinogenic products. However, ASC in this concentration range aggravates tissue damage. The objective of this study was to optimize ASC treatment parameters to balance antimicrobial activity with quality retention of shredded carrots. Shredded carrots were immersed for either 1 min in 100, 250 or 500 µL L^?1 ASC solutions or 2 min in 200 µL L^?1 chlorine or water (control). Treated samples were spin‐dried and packaged in polypropylene bags and stored at 5 °C for up to 21 days. Carrots were evaluated at 7‐day intervals for visual appearance, package atmosphere composition (O₂ and CO₂), product firmness, tissue electrolyte leakage and pH. The microbial growth, including total aerobic bacterial counts, total coliforms/Escherichia coli, yeast and mold counts and lactic acid bacterial counts on the products was also determined. Treatments with all concentrations of ASC reduced the aerobic bacterial counts, coliform/E. coli counts, yeast mold and counts and lactic acid bacterial populations by 1.2–2.0 log cfu g^?1 when compared with the water‐washed and unwashed samples. During storage, unwashed samples had a sharp increase in lactic acid bacterial populations accompanied by a sharp decline in pH readings and rapid loss in firmness and tissue integrity; samples washed with 100 µL L^?1 ASC maintained the best overall visual quality, accompanied by the retention of tissue integrity and firmness. Therefore, 100 µL L^?1 was determined as the optimum concentration of ASC for maintaining overall quality and firmness, inhibiting microbial growth and prolonging the shelf‐life of shredded carrots. Copyright © 2006 Society of Chemical Industry     

UV-Visible Spectroscopy and Multivariate Classification as a Screening Tool to Identify Adulteration of Culinary Spices with Sudan I and Blends of Sudan I + IV Dyes

This work propose a feasible, rapid, and simple method for detecting culinary spices adulterated either with Sudan I dye or blends of Sudan I + IV dyes at three concentration levels. The method is based on the use of UV-visible spectroscopy with multivariate analysis. Four types of spices were studied: three paprika varieties (mild, hot, and smoked) and a spice commonly consumed in Argentina called aji molido. Principal components analysis was firstly applied as an exploratory analysis and then, two classification techniques were used: K-nearest neighbors (KNN) and partial least squares-discriminant analysis (PLS-DA). Three classes were defined: unadulterated samples and adulterated samples with Sudan I or blends of Sudan I + IV dyes at 1, 2.5, and 5 ppm (mg L^?1). Classification techniques gave satisfactory results: between 89 and 100 % for PLS-DA and between 83 and 92 % for KNN. The sensitivity and specificity of the models were above 83 %. It has to be highlighted that none of the adulterated samples were assigned as unadulterated, which is very positive because of the implication that these results have on consumer health. The capability of detecting mixtures of Sudan dyes is a very important advantage because each Sudan dye generates different hazardous metabolites in human body so their toxicity may be enhanced by the simultaneous presence of such dyes.     

New Insights in the Use of Trehalose and Modified Starches for the Encapsulation of Orange Essential Oil

During the encapsulation of aromas by spray-drying, some volatile components may be lost; consequently, the sensory profile could be modified in the final product. Therefore, the selection of the carrier matrix for the encapsulation is crucial to obtain high aroma retention and long shelf-life stability, reduce aroma oxidation and increase physical stability of the powder. With the aim of studying the use of trehalose for the encapsulation of orange essential oil, emulsions were prepared containing mixtures of trehalose–maltodextrin (TMD) and sucrose–maltodextrin (SMD). Two modified starches were used as emulsifiers. The emulsions were spray-dried and stored at 25 and 37 °C. The aroma retention was evaluated using head space–solid phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC-MS) and by sensory evaluation. In addition, some physical properties of orange essential oil powders, such as water sorption and glass transition temperature (T _g), were determined. The sensory profiles obtained for TMD and SMD were different: TMD formulations retained mainly limonene, while SMD retained mostly α-pinene and myrcene. The modified starches (Capsul and Hi Cap) used as emulsifiers also affected the retention of certain volatiles. Therefore, the selection of components in the carrier matrix is relevant to the retention of aromas in orange oil powders. Regarding the physical properties, TMD formulations presented better characteristics in comparison to SMD, particularly due to the higher T _g values. The high aroma retention levels and the good physical characteristics are promising results in relation to the inclusion of the developed formulations in dehydrated citric juices.     

Evaluation of Structural Shrinkage on Freeze-Dried Fruits by Image Analysis: Effect of Relative Humidity and Heat Treatment

Stability of many dehydrated systems is related to the formation of a glass during drying. Highly porous materials, such as those prepared by freeze-drying are susceptible to shrinkage post-drying when stored at not optimal conditions. The aim of this study was to evaluate the occurrence of structural shrinkage on freeze-dried fruits through image analysis in relation to relative humidity (RH) and heat treatment. Freeze-dried fruits were humidified between 11 and 84 % RH at 25 °C for 14 days, and then stored at 45 °C. Sugar and water content, thermal transitions, and volume changes were determined. The shrinkage degree of fresh, lyophilized, humidified, and heat-treated samples was assessed by image analysis. The freeze-drying process did not produce important changes on fruits volume. At low RH values (11–22 % RH), the reduction of the cylinders volume was lower than 15 %. The maximum shrinkage values at each RH were attained in the initial period of humidification (first and second days), and then shrinkage rate decreased markedly, reaching a nearly constant value. The shrinkage degree increased with the increase in RH, reaching values up to 60 % volume reduction. During heat treatment, the volume reduction was less than 10 %. The shrinkage degree was limited by the structural characteristics of the fruits. The structural changes were strongly influenced by variables such as water content, glass transition temperatures, and storage time. In this work, the degree of shrinkage could be followed by image analysis and the use of a mechanical modeling software.