RESUMO Drying time and post-harvest quality of onion bulbs submitted to artificial curingAfter harvest, onion bulbs are submitted to curing, whose objective is to provide loss of moisture in leaves and drying of outer layers (peel) of bulbs, reaching attractive external coloration and reduction in the intensity of rottenness. The objective of this study was to use an air treatment unit (ATU) -known as heat pump -as an alternative drying method, and to evaluate drying time and preservation of the chemical and physical characteristics. The experiment was carried out in a complete random design with ten replicates and three treatments, which were the following: T 1-(control) natural curing in shed; (2) T 2-(aeration with air artificially heated by propane burning); and (3) T 3-(aeration with artificially dehydrated and heated air using ATU). Curing completion time, relative water content (RWC) of the skin and inner layers, pulp color and skin coloring, total titratable acidity (TTA), total soluble solids (TSS), visual index of dormancy breaking (VID), and fresh weight loss (FWL) were evaluated in this study. No significant difference (p < 0.05) were found for TTA, TSS, VID, FWL, and pulp color among treatments. It can be concluded that T 3 promoted a faster curing (12 hours) of bulbs, which provided bulbs with drier skin and intense yellow color. Tempo de secagem e qualidade pós-colheita de bulbos de cebola submetidos à cura artificialApós a colheita da cebola, realiza-se a cura cuja finalidade é proporcionar a perda da umidade das folhas e secagem das películas externas (casca) dos bulbos, alcançando coloração externa atrativa e redução da intensidade de podridões. Objetivou-se com este trabalho utilizar uma unidade de tratamento de ar (UTA), conhecida como bomba de calor, como método alternativo de secagem e avaliar o tempo de secagem e a preservação das características químicas e físicas dos bulbos de cebola após a cura. O experimento foi conduzido no delineamento inteiramente casualizado com dez repetições e três tratamentos que consistiram em: T 1 -(Testemunha) cura natural realizada em galpão. T 2 -(aeração com ar aquecido artificialmente pela queima de propano) e T 3 -(aeração com ar aquecido e desidratado artificialmente por meio da UTA). Avaliou-se o tempo de finalização da cura, teor relativo de água (TRA) da casca e películas internas, coloração da casca e polpa, acidez total titulável (ATT), sólidos solúveis totais (SST), índice visual de superação da dormência (IVD) e perda de massa fresca (PMF). Não houve diferença significativa (p < 0,05) para a ATT, SST, IVD, PMF e coloração da polpa entre os tratamentos estudados. Conclui-se que o T 3 permitiu a cura dos bulbos de forma mais rápida (12 horas), proporcionando bulbos com casca mais seca e coloração amarelo intenso.Palavras-chave: Allium cepa; características químicas e físicas; métodos de secagem; ar aquecido.Drying time and post-harvest quality of onion bulbs submitted to artificial curing Rev. Ceres, Viçosa, v. 63, n.6, p. 822-828, nov/dez, 2016

Popcorn (Zea mays var. everta) has a higher commercial value than common maize, in addition to being a popular food among consumers. Today, there is a constant search for cultivars with superior performance for several traits of interest in the case of popcorn, yield and popping expansion. On this basis, this project proposes to characterize progenies of popcorn with different values of expansion capacity regarding chemical composition and micromorphology. Kernels from the fifth cycle (C5) of intrapopulation recurrent selection were evaluated. The progenies were selected based on the popping expansion volume of their kernels. The kernels were quantified for amylose and analyzed for starch granule arrangement and pericarp thickness by scanning electron microscopy. Progenies with low popping expansion volume (0 and 7 mL g-1) showed amylose contents of 21.24 and 20.18%, respectively; a less compact endosperm, with individual starch granules interspaced with empty spaces; and pericarp thickness between 40.94 and 38.99 µm, respectively. By contrast, progenies with high popping expansion volume (30 and 35 mL g-1) showed amylose contents of 23.92 and 26.10%; a vitreous endosperm; more-compact starch granules without empty spaces in between; and pericarp thickness between 107.66 and 107.84 µm. Progenies with higher popping expansion volume exhibited a thicker pericarp, a high amylose percentage and a more-compact endosperm, whereas those with the lower expansion volumes showed a thinner pericarp, a lower amylose percentage and individual starch granules.

It is acknowledged that mechanical damage is a major cause of post-harvest losses of potato tubers and the curing is an indispensable process to increase resistance to excoriation. Furthermore, the use of lower curing temperatures is required to maintain the quality and prolong the durability of the tubers. However, they may not allow adequate regeneration of the damage periderm, besides this effect being variable among genotypes. The present study evaluates histological outcomes in the periderm derived from the mechanical damage through a simulation of excoriation, as it is the most common during the harvest and post-harvest stages. Therefore, the objective of this study was to determine the effect of reducing the curing temperature on the number of layers and on the thickness of the damage periderm of potato tubers of cv. Innovator. Histometric analysis of the cork, phellogen, phelloderm and the total periderm of tuber, was performed using the Image-Pro Plus software (MediaCybernetics) after curing for 15 days. The number of layers and thickness of each periderm structural layers were determined from six measurements for each repetition. After curing, there was no formation of the cork and phelloderm in the tubers conducted at 8 ° C under the excoriation treatment, while all components of the periderm were formed at 14 and 20 °C. At 8 and 14 °C, the phellogen differentiated similarly in tubers conducted at control and mechanical damage treatments, while at 20 °C the thickness did not differ in any component of the periderm. The phellogen at 14 and 20 °C did not differ in the number of layers and thickness. The visual aspect of the tuber injuries at 14 and 20 °C emphasizing the regeneration. It is concluded that the reduction of the curing temperature to 8 °C provided slower cell regeneration. However, it is possible to conduct the curing procedure at 14 °C, without compromising the formation of the damage periderm. The cultivar Innovator has rapid cell regeneration at higher curing temperatures, therefore it is recommended that the tubers of this cultivar be cured at 14 or 20 ° C. The study evaluates the mechanical damage through a simulation of the damage by excoriation. The however, for a better understanding of the formation of the damage periderm, it is interesting that other studies evaluate different types of damage, such as impact, comprehension and abrasion, in order to assess the regeneration capacity according to the damage of this cultivar.

The objective of this study was to determine the storage efficiency and reconditioning of potato cv. Innovator for processing. Tubers were stored at 6, 7 and 8 °C in the dark for 30, 60, 90, 120 and 150 days and reconditioned at 15 °C for 15 days. TRS and RS were reduced as storage temperature increased from 6 + 15 °C to 8 + 15 °C. Regardless of temperature and storage time, sugar contents were suitable for industry; however non-enzymatic browning remained in category 2 for up to 60, 90 and 150 days in tubers stored at 6 + 15 °C, 7 + 15 °C and 8 + 15 °C, respectively. Starch was influenced by storage time, despite the absence of temperature effect. Regardless of the temperature, sprouting started at 90 days, but the growth of shoots was directly proportional to the increase in temperature. The PPO and POD increased at the beginning of storage but did not cause darkening before the frying. Reduction in storage temperature followed by reconditioning did not delay the onset of sprouting, but reduced the size of sprouts, maintained adequate sugar levels, however it promoted non-enzymatic browning.

RESUMO: A redução da taxa transpiratória é essencial para a manutenção da qualidade pós-colheita. A rápida remoção do calor através da técnica de pré-resfriamento proporciona a redução da taxa transpiratória em muitas frutas e hortaliças. As folhas de coentro são suscetíveis a rápida desidratação logo após a colheita. Assim, objetivou-se com este trabalho avaliar a influência do hidroresfriamento na conservação pós-colheita de folhas de coentro 'Português'. Para tanto, folhas de coentro foram arranjadas em maços de 25 g e submetidas ao armazenamento a 20°C e 54% UR (controle); pré-resfriamento e conservação a 20°C e 54% UR; conservação a 5°C e 81% UR; pré-resfriamento e conservação a 5°C e 81% UR. O pré-resfriamento foi realizado pela imersão dos maços em água gelada a 5oC por 10 minutos. Os maços pré-resfriados absorveram água, resultando em acréscimo de 4% no teor relativo de água (TRA) das folhas. Depois de 72 horas após tratamento hidrotérmico por 10 minutos, o TRA foi reduzido de 89,3 para 88,6% nos maços armazenados a 20°C e não houve redução quando armazenados a 5°C (89,1 para 90,7%). Assim, os valores do TRA nesse período permaneceram próximos ao TRA no momento da colheita. O hidroresfriamento manteve a turgescência das folhas por 3 e 4 dias de conservação dos maços a 20 e a 5°C, respectivamente. No entanto, mesmo as folhas permanecendo hidratadas, não houve aumento da vida de prateleira devido à ocorrência de degradação da clorofila. O teor de clorofila foi reduzido em 18 e 19,8% nas folhas pré-resfriadas e conservadas a 20 e 5°C, respectivamente, ocasionando o descarte dos maços devido ao amarelecimento das folhas. Para as folhas que não foram submetidas ao pré-resfriamento, o teor de clorofila não foi alterado significativamente, sendo o descarte devido ao murchamento das folhas após 48 e 96 h da colheita para os maços conservados a 20 e 5oC, respectivamente. Portanto, a conservação do coentro a 5°C, manteve a qualidade dos maços, mesmo sem uso do resfriamento.