The growth of ochratoxigenic fungus and the presence of ochratoxin A (OTA) in grapes and their derivatives can be caused by a wide range of physical, chemical, and biological factors. The determination of interactions between these factors and fungal species from different climatic regions is important in designing models for minimizing the risk of OTA in wine and grape juice. This study evaluated the influence of temperature, water activity (aw), and pH on the development and production of OTA in a semisynthetic grape culture medium by Aspergillus carbonarius and Aspergillus niger strains. To analyze the growth conditions and production of OTA, an experimental design was conducted using response surface methodology as a tool to assess the effects of these abiotic variables on fungal behavior. A. carbonarius showed the highest growth at temperatures from 20 to 33°C, aw between 0.95 and 0.98, and pH levels between 5 and 6.5. Similarly, for A. niger, temperatures between 24 and 37°C, aw greater than 0.95, and pH levels between 4 and 6.5 were optimal. The greatest toxin concentrations for A. carbonarius and A. niger (10 μg/g and 7.0 μg/g, respectively) were found at 15°C, aw 0.99, and pH 5.35. The lowest pH was found to contribute to greater OTA production. These results show that the evaluated fungi are able to grow and produce OTA in a wide range of temperature, aw, and pH. However, the optimal conditions for toxin production are generally different from those optimal for fungal growth. The knowledge of optimal conditions for fungal growth and production of OTA, and of the stages of cultivation in which these conditions are optimal, allows a more precise assessment of the potential risk to health from consumption of products derived from grapes.

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This work evaluates fresh-cut carrots (FCC) coated with montmorillonite (MMT) subjected to passive modified atmosphere packaging. Carrots were sanitized, cooled, peeled and sliced. Half of the FCC were coated with MMT nanoparticle film and the other half were not. All FCCs were packed in a polypropylene rigid tray, covered with a polypropylene rigid lid or sealed with polyethylene + propylene film, in four treatments (RL, rigid lid; RLC, rigid lid + coating; ST, sealed tray; STC, sealed tray + coating). FCCs were stored at 4 °C and were analyzed weekly for 4 weeks (total antioxidant activity by 2,2-diphenyl-1-picryl hydrazyl method and the β-carotene/linoleic acid, phenolic compounds, organic acids and volatile compounds). The use of coating film with starch nanoparticles and a modified atmosphere leads to the preservation of the total antioxidant activity, the volatile and organic acids of FCC.

O trabalho objetivou a caracterização físico-química de biscoitos aromatizados com especiarias e enriquecidos com farinha da casca e do talo da cenoura (FCTC). Os biscoitos foram elaborados por meio da substituição parcial da farinha de trigo por FCTC na proporção de 5%. Para o biscoito referência sem a adição de FCTC (F1) e os enriquecidos (F2) foram determinados os parâmetros físicos (massa, volume, densidade, fator de expansão, atividade de água e força de cisalhamento), químicos (pH, acidez total e carotenóides) e composição centesimal (umidade, cinzas, proteínas, lipídios e carboidratos totais). Para os parâmetros físicos, apenas a densidade apresentou diferença significativa (p > 0,05) entre as formulações. Nas determinações químicas, a F2 apresentou pH inferior (6,09) a F1 (6,36) e, para acidez titulável a F2 apresentou maior valor (6,39%) do que a F1(4,49%). Os teores de cinzas, umidade e proteínas em F2 (3,13, 5,91, 9,81%) e F1 (2,30, 6,81, 10,91%) apresentaram diferenças significativas (p > 0,05) entre si. O teor de carboidratos totais em F2 (70,02%) foi maior do que em F1 (67,49%). As diferenças entre os resultados obtidos na caracterização física e química das formulações podem ser atribuídas a adição da FCTC. As concentrações de β e α carotenos em F2 foram de 510 e 603 µg/100g, respectivamente, indicando a presença de substâncias bioativas oriundas da adição FCTC. Neste contexto, os resultados sugerem que o uso de resíduos de vegetais pode contribuir na redução do desperdício de alimentos e enriquecimento nutricional de alimentos prontos para consumo como os biscoitos. PALAVRAS-CHAVE:Bolacha. Vegetais. Daucus carota L. Reaproveitamento.

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