Cellulose nanocrystals (CNCs) were obtained from grape pomace through chemical and physical pretreatments. Bleached cellulose pulp was subjected to acid hydrolysis (AH) for 30 or 60 min and an ultrasound treatment to obtain CNCs (AH and AH). Compositional analyses of untreated (UGP) and pretreated (PGP) grape pomace showed the effectiveness of pretreatment in removing non-cellulosic components, recovering 80.1% cellulose in PGP (compared to 19.3% of UGP). Scanning and transmission electron microscopies were used to evaluate the CNCs morphology. AH in combination with ultrasound treatment led to needle-shaped structures and apparently more dispersed suspensions. Crystallinity index and thermal stability were studied by X-ray diffraction and thermogravimetric analysis, respectively. The AH sample presented high aspect ratio, crystallinity and thermal stability. CNCs toxicity was evaluated by exposing Caco-2 cells to CNCs suspension and evaluating their viability. Results showed that CNCs are non-toxic, opening the opportunity for their use on food and pharmaceutical applications.

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Microcrystalline cellulose (MCC) can provide improved properties when the aim is the development of biodegradable packaging materials. In this work the physicochemical properties of polysaccharide-based films (chitosan and starch) with the incorporation of MCC and the application of moderate electric field (MEF) and ultrasonic bath (UB) as treatments, were evaluated. For each treatment, the thickness, moisture content, solubility, water vapor permeability, contact angle, mechanical properties, along with its color and opacity were determined. The surface morphologies of the films were assessed by scanning electron microscopy (SEM). X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) were also performed. It was observed that the addition of different concentrations of MCC as well as the application of MEF are responsible for changes in the properties of the films, being this effect dependent on the polysaccharide used. Chitosan-based films were slightly yellow, transparent and presented a more homogeneous structure. The use of MEF was efficient in decreasing the permeability to water vapor in chitosan based films without MCC, as well as in production of films with a more hydrophobic surface. The addition of MCC promoted more opaque, rigid, less flexible and less hydrophobic films. Starch-based films were whitish, with a more heterogeneous structure and the application of MEF generated more hydrophilic films with lower tensile strength and Young's modulus. The films with MCC were more opaque, less flexible and less hydrophilic than the films without MCC. The composites presented good thermal properties, which increases their applicability as packaging materials. Therefore, the incorporation of MCC into polysaccharide-based films as well as the application of MEF can be an approach to change the properties of films.

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R E S U M OAs podridões em frutas e hortaliças, resultantes da atividade de agentes fitopatogênicos e da senescência natural, acarretam perdas qualitativas e quantitativas e, em consequência, perdas econômicas. Este artigo tem, como objetivo, discutir a eficácia, os benefícios e os limites do emprego do ozônio (O 3 ) enquanto agente sanitizante, na minimização da ocorrência de doenças fúngicas em produtos hortícolas. Neste contexto, a presente revisão bibliográfica realizada no banco de dados do SciELO e ScienceDirect, discute estudos encontrados sobre o emprego do ozônio e sua eficácia como agente sanitizante em alimentos. Desta forma, a revisão apresenta uma avaliação crítica das vantagens e desvantagens da ozonização, a contribuição e o impacto desta tecnologia para minimizar os danos e perdas pós-colheita, além do efeito desta tecnologia como uma alternativa ao uso do cloro, as formas de aplicação, o uso e segurança e a regulamentação do uso do ozônio na agroindústria. Ozonation as post-harvest technology in conservation of fruits and vegetables: A review A B S T R A C TRotting of fruits and vegetables resulting from the activity of plant pathogens agents and natural senescence, lead to qualitative and quantitative losses, and consequently economic losses. This article aims to discuss the effectiveness, benefits, use and limits of ozone as a sanitizing agent to minimize the occurrence of fungal diseases on fruits and vegetables. In this context, the present review of literature through SciELO and ScienceDirect database studies and discusses about application of ozone and its effectiveness as a post harvest sanitizer of fruits and vegetables. Thus the review presents a critical assessment of the advantages and disadvantages of ozonation, the contribution and the impact of this technology to minimize post-harvest damage and losses; its use as an alternative to the chlorine, application forms and safety and the regulation of ozone use in agroindustry. Palavras-chave:ozônio sanitização inativação microbiana

Brazil holds a series of favorable climatic conditions for agricultural production including the hours and intensity of sunlight, the availability of agricultural land and water resources, as well as diverse climates, soils and biomes. Amidst such diversity, Brazilian coffee producers have obtained various standards of qualities and aromas, between the arabica and robusta species, which each present a wide variety of lineages. However, temperatures in coffee producing municipalities in Brazil have increased by about 0.25 °C per decade and annual precipitation has decreased. Therefore, the agricultural sector may face serious challenges in the upcoming decades due to crop sensitivity to water shortages and thermal stress. Furthermore, higher temperatures may reduce the quality of the culture and increase pressure from pests and diseases, reducing worldwide agricultural production. The impacts of climate change directly affect the coffee microbiota. Within the climate change scenario, aflatoxins, which are more toxic than OTA, may become dominant, promoting greater food insecurity surrounding coffee production. Thus, closer attention on the part of authorities is fundamental to stimulate replacement of areas that are apt for coffee production, in line with changes in climate zoning, in order to avoid scarcity of coffee in the world market.

A goiaba é um fruto rico em zinco, fibras, vitamina A, vitamina C, vitamina E, ácido fólico e licopeno. Para se reduzir as perdas pós-colheita desta fruta, que é nutricionalmente considerada a “fruta completa”, neste trabalho foi avaliado o uso de revestimento filmogênico à base de amido de mandioca associado ou não a óleo essencial de cravo-da-índia sobre a qualidade e redução de perdas por antracnose em goiabas “Pedro Sato”. O revestimento à base de amido de mandioca permite a extensão da vida útil da goiaba em 3 dias, sob condição ambiente. O óleo de cravo-da-índia, associado ou não ao revestimento à base de amido, não aumenta a vida útil da goiaba, porém reduz a ocorrência de antracnose em goiabas ‘Pedro Sato’.

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