ABSTRACT The curing before storing the tubers is necessary for the formation of damage periderm, promoting greater post-harvest conservation. In which, the rate curing and the maintenance of the quality of the tubers depends on the temperature. This way, the search aimed to determine the effect of the curing temperature on the regeneration of the damage periderm and on the carbohydrate metabolism of cultivar Markies and Challenger potatoes tubers destined for industry. For this, the curing was carried out for 14 days on tubers with excoriation injury and tubers without excoriation (control) at temperatures of 8, 14 and 20 °C (RH ± 90%). The fresh mass loss rate (FMLR) daily was higher in the excoriation tubers. The excoriation injury and the temperature of 8 °C increased the total soluble sugar (TSS), reducing sugars (RS) and non-reducing sugars (NRS) of the tubers of ‘Markies’ and TSS of ‘Challenger’. The excoriation injury tuber the process of cell division was induced in the periclinal plane, forming phellogen, with few layers of collapsed cortical cells. In both cultivars, at 14 °C the new phellogen became more evident and at 20 °C some layers of a new cork were formed. In ‘Markies’ the development of new periderm was earlier than in ‘Challenger’, even at 8 °C. It is concluded that the temperature of 14 ºC provided better curing and regeneration of the excoriation periderm tubers maintain post-fry quality of potatoes destination by industry processing.

ABSTRACT. Excoriation damage is among the major causes of postharvest potato losses. Curing is known to increase the resistance of tubers to excoriation injury, with the temperature influencing the traumatic phellogen and periderm regeneration, as well as tuber processing quality. This study aimed to evaluate the effects of excoriation procedure and curing temperature on the industrial quality, histological characteristics, carbohydrate metabolism, and oxidative enzyme activity of potato tuber. Tubers with or without excoriation were cured at 8, 14, and 20°C for 15 days. Excoriation did not influence the levels of reducing sugars (RS), as well as polyphenoloxidase (PPO) and peroxidase (POD) activities. The concentrations of total soluble sugars (TSS) and non-reducing sugars (NRS) were higher in injured tubers, while reduction in curing temperature increased the concentrations of TSS, NRS, and RS. However, the sugar content was adequate as per the criteria of the pre-fried potato industry and potatoes classified in category 2 (USDA/fast-food industry color grading). The reduction in curing temperature also increased the activity of POD, despite the activity of PPO remaining unchanged. Formation of a closure layer from the outer parenchyma cells of the tuber that prevents desiccation and death of superficial cells, was observed. This protection was completed with the formation of the damage periderm. Periderm regeneration is faster at higher temperatures, 15 and 20°C, leading to a lower fresh mass loss and no enzymatic or non-enzymatic browning. The excoriation carried out at 14/20oC for 15 days was sufficient for curing, and for maintaining suitable post-fry quality of potatoes.

ABSTRACT The refrigerated induce the sweetening of the potato, which results in the dark color. The objective of this study was to determine the temperature and shelf life of Markies potato tubers under refrigerated storage for the processing of French fries. The levels of total soluble sugar (TSS), reducing sugars (RS), peroxidase (POD) and polyphenoloxidase (PPO) activity, color after frying and start of sprout were determined. The accumulation of TSS started at 30 days in the tubers at 4 and 5 °C and in the tubers at 6 and 8 °C, at 150 days. The activity of POD and PPO were not influenced by temperature or storage time. Tubers at 4 e 5 °C showed higher TSS and RS contents and darker color after frying than tubers stored at 6 and 8 °C which had their color maintained within the industry-acceptable standard up to 240 days of storage. Temperatures of 4 and 5 °C delayed the onset of sprouting, starting at 150 days, and at temperatures of 6 and 8 °C, the onset of sprouting occurred from 90 and 60 days of storage, respectively. It is concluded that the cultivar Markies should be stored at 6 °C for 240 days.

Abstract 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: O objetivo deste trabalho foi avaliar a ação do paclobutrazol (PBZ) sobre o crescimento e valor ornamental de dois acessos e duas cultivares comerciais de pimenta ornamental - Biquinho Vermelha e Bode Amarela. Uma solução aquosa de 250 mL de PBZ foi adicionada aos vasos com 0, 20, 40 e 60 mg L-1 i.a., quando as plantas apresentavam 12 cm de altura. Ao final do crescimento, determinaram-se os seguintes parâmetros: a altura das plantas, o teor de clorofila das folhas, o número de frutos e de folhas, e a compacidade da parte aérea no estádio de maturidade das plantas, com 30% de frutos maduros. Independentemente da concentração de PBZ aplicada, houve redução da altura das plantas e aumento da concentração de clorofila nas folhas. O PBZ não melhorou as características ornamentais dos genótipos 'Biquinho Vermelha' e 2334PB, o que resultou em plantas inadequadas aos requisitos do mercado. Para os genótipos 2345PB e 'Bode Amarela', a aplicação de 20 mg L-1 de PBZ é a mais indicada e resulta em plantas com características ornamentais adequadas requeridas pelo mercado nacional de flores e plantas ornamentais.

Abstract: The objective of this work was to evaluate the action of paclobutrazol (PBZ) on the growth and ornamental value of two pepper accessions and two commercial cultivars of ornamental pepper - Biquinho Vermelha and Bode Amarela. A PBZ aqueous solution (250 mL) was used to soak the substrate at 0, 20, 40, and 60 mg L-1 a.i. concentrations when the plants had 12 cm height. At the end of plant growth, the follwoing parameters were evaluated: plant height, chlorophyll content in leaves, number of fruit and leaves, and canopy compactness at the time the plants reached maturity to be marketed, with 30% of ripe fruit. Irrespective of the applied PBZ concentration, plant height diminished, and chlorophyll content increased. PBZ did not improve the ornamental characteristics of the genotypes 'Biquinho Vermelha' and 2334PB, which resulted in unsuitable plants for market requirements. For the genotypes 2345PB and 'Bode Amarela', the application of 20 mg L-1 of PBZ is the most indicated, and it results in plants with adequate ornamental characteristics required by the national market of flowers and ornamental plants.