-This study aimed to evaluate the quality of minimally-processed cassava treated with antioxidants and a starch-based edible coating. Cassava roots were washed, cooled, immersed in cold water, peeled and then cut. Root pieces were then immersed in a chloride solution, centrifuged, and subsequently immersed in either a starch suspension (3%), a solution containing antioxidants (3% citric acid and 3% ascorbic acid), or in both the coating and antioxidant solutions. Coated root pieces were dried at 18 ± 2°C for 1 hour, then packaged into polypropylene bags (150 g per pack) and kept at 5 ± 2°C for 15 days, and assessed every 3 days. A completely randomized design was used in a 4 × 6 factorial consisting of the treatment (control, coating, antioxidant, or coating and antioxidant) and the storage period (0, 3 6, 9, 12 or 15 days), with three replicates in each group. The pH, blackened area and peroxidase and polyphenol oxidase activities of the cassava was reduced in treatments containing antioxidants and the scores of visual analysis and phenolic content were higher. Therefore, treatment with antioxidants was effective for reducing browning in minimallyprocessed cassava, retaining the quality of cassava pieces stored for 15 days at 5 ± 2°C. The combination of antioxidants and the edible coating showed no improvement compared to treatment with antioxidants alone.Keywords: Manihot esculenta Crantz. Physiological changes. Postharvest. ESCURECIMENTO EM MANDIOCA DE MESA MINIMAMENTE PROCESSADA COM USO DE ANTIOXIDANTES E REVESTIMENTO DE AMIDORESUMO -Objetivou-se avaliar a qualidade de mandioca de mesa minimamente processada com o uso de antioxidantes e revestimento comestível a base de amido. Raízes de mandioca de mesa foram lavadas, resfriadas, imersas em água fria, cortadas e descascadas. Os pedaços foram imersos em solução clorada, centrifugados e imersos em suspensão de amido (3%) ou em solução contendo antioxidantes (ácido cítrico 3% e ácido ascórbico 3%) ou em ambos (revestimento + antioxidantes). Os pedaços contendo revestimento foram secos em sala climatizada a 18 ± 2 °C por 1 hora. Os pedaços foram embalados em polipropileno, contendo 150 g por embalagem, e mantidos a 5 ± 2 °C por 15 dias, com avaliações a cada três dias. Foi utilizado o DIC, em esquema fatorial 4 x 6 [controle, revestimento, antioxidantes e revestimento + antioxidantes x dias de conservação (0; 3 6; 9; 12 e 15 dias)] com 3 repetições. Verificou-se que os valores de pH, área escurecida e as atividades da peroxidase e polifenoloxidase foram menores e as notas da análise visual e o teor de fenólicos totais foram superiores nos tratamentos contendo antioxidantes. O uso dos antioxidantes foi eficiente na redução do escurecimento em mandioca de mesa minimamente processada, mantendo os pedaços com qualidade por 15 dias a 5 ± 2 ºC e a associação de antioxidantes e revestimento comestível não apresentou melhorias em comparação aos antioxidantes isolados. Palavras-chave:Manihot esculenta Crantz. Alterações fisiológicas. Pós-colheita.

The aim of this study was to examine oxidative protection and enzymatic browning in the storage of minimally processed cassava and their relationship with population density and harvest age. Population densities were 1.0, 1.25, 1.5, and 1.75 plants m−2. After being harvested at 300, 360, or 420 days after planting, cassava were minimally processed and stored at 5 ± 2°C. It was observed that superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) play key roles in the tolerance of young roots to browning. Planting density, however, does not appear to be a key factor modulating the activity of the enzymes studied. Practical applications Younger harvested cassava roots, harvested at 300 days, are more tolerant to enzymatic browning. This appears to be in part due to enzymatic activity modulation of the SOD, CAT, and POD enzymes. In addition, it has been demonstrated that agronomic techniques aimed at increasing productivity, such as increasing the planting density of cassava, do not alter the biomarkers of postharvest quality. In summary, evidence that field management may be an efficient approach to improving the conservation of minimally processed cassava is provided. We believe that the findings of this paper will be of great interest regarding the influence of field management on the postharvest quality of freshly cut cassava and will also provide applicable results relating to its production chain.

Quantitative proteome analysis of four developmental stages of pericarp tissues of the açaí berry (Euterpe oleracea Mart.) was performed by the isobaric labeling of peptides with iTRAQ 4-plex, hydrophilic interaction liquid chromatography pre-fractionation of labeled peptides, and high-performance mass spectrometry analysis. This analysis resulted in the identification of 4286 proteins, of which 476 presented differential abundance between the stages. The differential abundance of these proteins was seen to be coordinated with the metabolic demands during cell division, lignification, and cell expansion at developmental stages 1 and 2 as well as phenolic acid accumulation and metabolic changes in the fruit maturation at developmental stages 3 and 4. The distinct accumulation of anthocyanins observed in the pericarp at developmental stage 4 was correlated with the increase in abundance of some key biosynthetic enzymes, such as leucoanthocyanidin dioxygenase, anthocyanidin O-3-glycosyltransferase, and UDP-glycosyltransferase. Here, evidence is also provided for the presence in the açaí berry of secondary metabolites not previously described in açaí, such as pterostilbene, matairesinol, and furaneol. Together, these results will pave the way for studies aimed at the genetic improvement of the nutritional properties of this important fruit crop.

There are many procedures for obtaining minimally processed fruits and vegetables, aiming at adding value and maintaining the quality for a longer period. Cassava is a root that adapts to minimum processing technology, because the tissues are more resistant, what helps in obtaining different cut shapes and formats. However, it is a root susceptible to browning and microbiological contamination. In this chapter, methodologies and procedures are described to obtain alternative formats for minimally processed cassava, which was generally denominated "babycassava",called"babytolete", "cateto",and "rubiene". Besides that, some preharvest and postharvest factors that influence the shape and quality of "babycassava" formats will be addressed. It was verified that preharvest factors could influence the quantitative and qualitative aspects, resulting in browning of the minimally processed root. Some of the factors studied seem to regulate key enzymes in which they mediate oxidative reactions that cause browning, such as polyphenol oxidase and peroxidase, and other enzymes that participate in the reactive oxygen species (ROS) elimination process. In this way, the turning stage of "babycassava" manufacturing removes the parenchyma, minimizing the effect of browning-related enzymes.

Auxins are known to regulate xylem development in plants, however, their effects on water transport efficiency are poorly known. Here we used tomato plants of the diageotropica mutant (dgt), which has impaired function of a Cyclophilin 1 cis/trans isomerase involved in auxin signaling, and its corresponding wild type (WT) to explore its effects on plant hydraulics and leaf gas exchange. The xylem conduits of dgt showed a reduced hydraulically-weighted vessel diameter (Dh) (24-43%) and conduit number (25-58%) in petioles and stems, resulting in lower theoretical hydraulic conductivities (Kt); on the other hand, no changes in root Dh and Kt were observed. The measured stem and leaf hydraulic conductances of dgt agreed with the Kt values and were lower (up to 81%) as well; however, despite dgt and WT showed similar root Dh and Kt, the measured root hydraulic conductance of dgt was 75% lower. The dgt mutation increased the vein and stomata density, which could potentially increase photosynthesis. Nevertheless, even presenting the same photosynthetic capacity of WT plants, the dgt showed a photosynthetic rate c. 25% lower, coupled with a stomatal conductance reduction of 52%. These results clearly demonstrate that increases in Dv and Ds only result in higher leaf gas exchange when accompanied by higher hydraulic efficiency.