Gustavo Henrique de Almeida Teixeira

Blackspot bruise is a common defect caused by physical injury of potato tubers that triggers internal enzymatic browning, leading to significant postharvest losses. Reducing the development of internal discolouration has enormous benefits for the industry. The objective of this study was to evaluate the efficacy of nitric oxide (NO) and 1-methylcyclopropene (1-MCP) in controlling blackspot enzymatic browning in Clearwater Russet, Russet Burbank, and Russet Norkotah potato cultivars. Tubers from these three cultivars were treated with NO (98 mL L ⁻¹ ; 5 h) and 1-MCP (0.139 mL L ⁻¹ ; 24 h), in addition to the untreated control. After the application of these treatments, half of the tubers were stored at 7.2 °C and 95% relative humidity (RH) for 14 days. The remaining half of the tubers were injured to induce blackspot bruising and then held for 24 h at 23 °C and 65% RH to allow browning symptoms to develop. 1-MCP and NO treatments significantly reduced blackspot enzymatic browning score to 1.3 and 1.1, respectively, compared to the untreated control (1.8) on a scale from 1 (lightest) to 4 (darkest). Treated tubers maintained higher lightness (L*) value of bruise area after peeling 70.47 in 1-MCP and 69.35 in NO, compared to the control, 66.67. Biochemical profile does not show any significant changes with treatment. This study provides preliminary proof of approaches to minimise bruise-associated discolouration in potatoes, with the potential to reduce postharvest losses and enhance the marketable value of fresh potatoes, which needs further verification to see its further implications.

Physiological and biochemical changes during potato storage affect phenolic metabolism, antioxidant capacity, and polyphenol oxidase (PPO) activity, influencing enzymatic browning. This study examined four russet-type cultivars: Clearwater Russet, Russet Norkotah, Russet Burbank, and Ranger Russet, after one and six months of storage at 7.2 °C and 95% relative humidity. Browning intensity (ΔL) increased in all cultivars, with Russet Burbank exhibiting the highest (7.17) and Clearwater Russet the lowest (5.72) color changes. Total phenolics increased approximately fourfold (336–502 to 1,344–1,826 µg g−1 FW), accompanied by higher caffeic, rutin, sinapic, and chlorogenic acids, while ascorbic acid declined from 466.0 to 131.6 µg g−1 FW. Amino acids also increased, supporting enhanced melanin synthesis. ΔL correlated positively with PPO activity (r = 0.80), phenolics (r = 0.62), and chlorogenic acid (r = 0.82), but negatively with ascorbic acid (r = −0.33). Clearwater Russet exhibited lower browning, indicating cultivar-dependent responses influencing postharvest quality.

Recently, it was observed that red, blue and far-red lights and different intensities (0.1 and 1.0 μmol m⁻² s⁻¹) of light-emitting diode (LED) reduced potato sprout growth but did not effectively inhibit sprouting in physiologically aged tubers. Therefore, this study aimed to identify the physiological and biochemical changes and sprout development in potatoes treated with LED lights or with 3-chlorophenyl carbamate (CIPC). To achieve this, ‘Asterix’ potatoes were harvested, cured at 15 °C (90–93% RH) for 15 days and treated with red (5 µmol m⁻² s⁻¹), far-red (5 µmol m⁻² s⁻¹) and blue (1 µmol m⁻² s⁻¹) LED lights, in addition to the negative control (dark) and positive control (0.022 g L⁻¹ of CIPC) treatments. Potatoes from the light treatments were exposed to LED lights 24 h a day throughout the storage period, under optimal conditions for sprout development (16.7 ± 1 °C and 91.5 ± 1% RH). Tubers treated with blue and far-red LED light exhibited longer dormancy, fewer sprouts and smaller sprouts over the storage period. The carbohydrate content (starch and reducing sugars) was not affected by light treatments; however, total soluble sugar content was lower in tubers kept in the dark and higher in those treated with far-red LED light, which was not related to sprouting control. Therefore, it is suggested that other signalling mechanisms may be involved in sprout control using LED lights.

Understanding the storage requirements of emerging potato cultivars is paramount for effective storage management. Thus, the objective of this study was to quantify the respiration rates of the standard Russet Burbank, and the new cultivars Ivory Russet, Dakota Russet, and Rainier Russet potatoes to understand the relationship between respiration rate and quality parameters during storage. Tubers were cured at 12.8 °C and 95% relative humidity (RH) for 14 days before gradually transitioning to 5.5, 7.2, or 8.9 °C (95% RH). Lower respiration rates were observed at 5.5 °C, with comparable rates at 7.2–8.9 °C. Dakota Russet had lower respiration rates (0.95 mg CO₂ kg⁻¹ h⁻¹) while Rainier Russet the highest (1.29 mg CO₂ kg⁻¹ h⁻¹). Sucrose content was negatively affected by respiration of Ivory Russet, Rainier Russet, and Russet Burbank, glucose content was affected by all cultivars, though. Fry color (Photovolt reflectance) was positively correlated to the respiration rates of all cultivars. The respiration rates had low correlations with all quality parameters.

Our previous studies have shown that ‘Palmer’ mangoes immersed in solutions containing 2.5% sorbitol and stored under a controlled atmosphere (CA) at 8 °C for 30 days had fewer symptoms of a chilling injury. However, there is no information regarding the effectiveness of sorbitol treatment in other atmospheres and/or in combination with lower temperatures. Thus, the objective of this study was to assess the impact of dipping ‘Palmer’ mangoes in 0.1% and 2.5% (w/v) sorbitol solutions and storing the fruit under a CA without atmosphere modification (21 kPa O₂ + 0.03 kPa CO₂) at 8 °C/95% relative humidity (RH) or with 5 kPa O₂ + 5 kPa CO₂ at 4 °C/95% RH for 28 days. The fruits were evaluated periodically for chilling injuries, quality, and oxidative metabolism. A chilling injury (CI) was correlated with increased fresh weight loss (FWL) and changes in the color of the epicarp (L_peel, h°_peel, and C_peel) and mesocarp (L*_pulp). Lipid peroxidation (LP_pulp and LP_peel) and the hydrogen peroxide content (H₂O_2peel and H₂O_2pulp) were associated with the development of a CI, particularly after being transferred to ambient. The treatment with 2.5% sorbitol was more effective in minimizing the chilling injury symptoms and did not compromise the fruit quality, especially when it was stored at 4 °C in association with a CA containing 5 kPa O₂ + 5 kPa CO₂. This treatment reduced lipid peroxidation and increased the activities of the superoxide dismutase (SOD) and ascorbate peroxidase (APX) enzymes in the epicarp and mesocarp, providing greater cold tolerance. The use of 2.5% sorbitol has been identified as the most efficacious approach for mitigating the adverse impacts of chilling injuries, preserving the fruit quality, and enhancing oxidative metabolism, even at lower temperatures. Thus, this treatment represents a viable alternative for managing chilling injuries in mangoes.

Morning glory species are weeds very common in tropical crops, where they cause direct and indirect damage. The management of these species primarily relies on the application of herbicides, disregarding the growth stage and spatial distribution. Studies addressing new techniques for identifying these species may contribute to the development of proximal sensors for carrying out specific and rational management. Thus, the objective of this work was to use near infrared spectroscopy (NIRS) and multivariate analysis to discriminate two species of morning glory in three growth stages. NIRS spectra were collected from Ipomoea hederifolia and Merremia aegyptia were collected at three different stages in the spectral range of 4.000 to 10.000 cm-1. PCA and PC-LDA were used to analyze the entire spectrum and specific bands. NIRS associated with PCA and PC-LDA were sufficient to discriminate I. hederifolia and M. aegyptia species and their growth stages. PCA allowed a proper segregation of stages and species when applied individually PC-LDA correctly classified between 90.93 to 100% of species and stages. The best discrimination results were observed in the NIR spectra ranges from 4.500 to 6.000 cm-1 and 4.500 to 6.000 + 6.500 to 7.750 cm-1. This study represents an advance in the research and implementation of NIRS technology to discriminate weed species for the future development of equipment to assist in the adoption and/or performance of a specific management of weeds, capable of contributing to the reduction in the use of herbicides in crops.