The effects of ultraviolet B (UV-B) irradiation on color quality and decay rate of Capia pepper during postharvest storage

Abstract The current study demonstrates that the ultraviolet-B (UV-B) irradiation not only helps in improvement of the red color of the peppers but also reduces their rate of decay. The Capia peppers were harvested at their full red ripe stage and subjected to the UV-B treatment at doses 4.46 kJ m–2 (UV-B 15) and 8.93 kJ m–2 (UV-B 30). Post irradiation, the peppers were packaged and stored at 5 ± 1 °C temperature with 90-95% RH for 49 days. The UV-B treated group showed lower L* values, but higher a* and h° values as compared to the control group. Therefore, it was found that both the doses of UV-B radiations could enhance the quality of red color of the peppers. However, the lower dose (4.46 kJ m-2) was found to be optimal for reducing the decay rate of the peppers. The UV-B 30 peppers showed highest respiration rate, electrolyte leakage, total soluble solids, and the amount of weight loss

Biochemical and color changes of fresh-cut melon (Cucumis melo L. cv. Galia) treated with UV-C

The importance of minimally processed commodities in the retail groceries of most developed countries has been rising continuously during the last decades. Cantaloupe melon is used more than any other fruit in fresh-cut processing. Ultraviolet (UV) light has been extensively used to simulate biological stres in plants and for determining resistance mechanisms of plant tissues. In this study the effect of ultraviolet irradiation on some properties of fresh-cut cantalope melon was determined during storage. Freshly cut cantalope melons cubes treated with ultraviolet irradiation at the doses of 1, 2 or 3 min before storage, and then placed in a cold room at 5±1°C temperature and 85-90% RH. Hue angle values of control group is low compared to UV-C treated samples, whereas L values of is high. EL of UV treated samples higher than those of control group. Total soluble solids of fresh-cut melon samples in UC3 treatment increased during storage. The results indicate that UV-C treatments on fresh-cut cantaloupe melon cubes increased total soluble solids independently from water loss

Postharvest UV-B treatments increased fructose content of tomato (Solanum lycopersicon L. cv. Tayfun F1) harvested at different ripening stages

Abstract In the postharvest stage, taste and flavor are the key components of the marketability of tomato. Therefore, greater emphasis is now being placed on improving traits such as sugar content. In this study postharvest ultraviolet-B (UV-B) treatments on sugar, total soluble solids, and color of tomatoes harvested at different stages were investigated. Tomatoes harvested at turning, pink, and red stages were treated with two different doses of UV-B irradiation: UVB4 and UVB8. Color L* and hue angle values of tomatoes treated with UV-B were found to be high, which means the red color of tomatoes was improved. UVB4 treatments increased the color a* and saturation index values of tomatoes at pink and red harvest stage, although it did not affect at the turning stage. Additionally, UV-B irradiation treatments had no effect on sucrose content of the tomatoes. Fructose, glucose, and TSS content of tomatoes treated with UVB8 at red harvest stage were found to be high. Hence, the results obtained from this study are of great importance in terms of providing an increase in the amount of sugar without the need for breeding, and also consumer satisfaction

Biochemical changes and color properties of fresh-cut green bean (Phaseolus vulgaris L. cv.gina) treated with calcium chloride during storage

Calcium chloride is widely used in industries as a firming agent, and also to extend shelf-life of vegetables. The aim of this study was to determine, the effect of different doses of calcium chloride on biochemical and color properties of fresh-cut green bean. Fresh-cut green beans were dipped for 90 seconds in 0.5%, 1%, 2% and 3% solution of calcium chloride at 25°C. The fresh-cut green bean samples were packaged in polystyrene foam dishes, wrapped with stretch film and stored in a cold room at 5±1°C temperature and 85-90% RH. Calcium chloride treatments did not retain the green color of samples. Whiteness index, browning index and total color difference (ΔE) values of CaCl2 treated samples were high. Saturation index and hue angle were low compared to the control, especially at higher doses of CaCl2. Polyphenol oxidase (PPO) enzyme activity in samples treated with CaCl2 at 3% doses, was low at the 7th days of storage than with other treatments. Fructose and sucrose content of samples increased in all treatment groups whereas glucose level decreased during the first 4th days of storage

Postharvest Treatments of Different Doses of Calcium Lactate in Combination with Chitosan Improves Biochemical Characters of Cucumis sativus L. during Storage

This study aimed to determine the effects of the postharvest coating created with different doses of calcium compounds and chitosan on the quality of the cucumbers during storage. For this purpose, cucumber fruits were dipped into solutions containing the doses of 2, 4, and 6% calcium chloride (CaCl2), calcium propionate (C6H10CaO4), and calcium lactate (C6H10CaO6) + 1.0% chitosan separately before storage. After the treatments, the cucumber fruits were dried and placed in boxes with plastic lids and stored at 7±1oC and 90-95% relative humidity for 20 days. Calcium change in fruits, flesh firmness (N), weight loss (%), fruit skin color (L*, a*, b*, hue angle, yellowness index), chlorophyll SPAD amount, total soluble solids (TSS), titratable acid (%), taste quality, electrolyte leakage (%), decay rate  (%) observations and analyzes were evaluated at five-day intervals during storage. According to the results, it was found that especially the dose of 2% calcium lactate was more effective in preserving fruit firmness and green color, increasing the amount of TSS, and also delaying the decay, amongst calcium chloride, calcium propionate, and calcium lactate treatments. The KT and CaP4 treatments were successful in reducing weight loss, whereas CaL4 and CaL6 were found to be effective in maintaining chlorophyll content. Also, it observed that CaK4 and CaK6 treatments were increased electrolyte leakage due to causing damage to the cell wall, thus the shortened storage time of cucumber fruits in this study

Natural and commercial antimicrobial agents that inhibit the growth of Listeria monocytogenes strains

Vinegar products have gained popularity as an all-natural antimicrobial agent in recent years. In the present study, the antimicrobial susceptibility of 29 Listeria monocytogenes strains isolated from ready-to-eat foods was detected against natural and commercial antimicrobial agents, vinegar produced from different raw materials, lemon juice, sodium bicarbonate, and hydrogen peroxide, by using the disc diffusion method. Different concentrations of antimicrobial agents were tested against varying cell densities of the L. monocytogenes strain (105, 106, and 107 CFU/mL). The inhibition zone diameter was measured to evaluate the antimicrobial effects of antimicrobial agents on L. monocytogenes strains. The inhibition zone diameters of L. monocytogenes strains were 6.0–8.8 mm and 6.0–11.3 mm against traditional and commercial vinegar types, respectively. The commercial vinegar types showed higher antimicrobial efficacy than the conventional ones. The inhibition zone diameters of L. monocytogenes strains against carbonate, lemon juice, and hydrogen peroxide were 6.0, 6.0–9.0, and 33.9–51.9 mm, respectively. The antimicrobial efficacy of hydrogen peroxide was the highest among the tested antimicrobial agents. This study showed that vinegar products have potential to be utilized as natural antimicrobials on food-borne pathogens like L. monocytogenes