Potassium and growth-promoting fungi improve the postharvest quality of grape tomato

Tomato plants respond well to potassium fertilization, whose insufficiency leads to a drop in fruit production and quality. On the other hand, the association of growth-promoting fungi (GPF) with roots has been shown to be able to optimize nutrient absorption, which implies lower financial costs and a decreased risk of loss of K applied to the soil. The objective of this study was to investigate the effects of inoculation with GPF and K rates on the postharvest quality of grape tomato hybrid ‘Mascot’ grown in a hydroponic system. The plants were cultivated in a hydroponic drip system using washed and sterilized sand as substrate. They were trained with two stems, leaving three bunches per stem. The experiment was carried out in a splitsplit-plot arrangement in a completely randomized design with three replicates. Ripe fruits were stored for 30 days in PET containers in storage chambers at a temperature of 25 °C. After 0, 10, 20 and 30 days of storage, five fruits were collected to determine the titratable acidity (TA) and soluble solids (SS), reducing sugars (RS) and vitamin C contents. The K rates provided an increase in the quality attributes. At low K rates, inoculation with GPF led to higher TA, SS, RS and vitamin C values. Inoculation of the plants with GPF improved the postharvest preservation of the fruits, especially when the plants underwent nutritional stress during cultivation.

Enhanced Antioxidant Activity of Fresh Fruits through Salicylic Acid/β-CD Hydroalcoholic Gels

Oxidation is an important cause of fruit spoilage, and therefore improving the antioxidant capacity of fresh fruits is beneficial to their preservation. Herein, fresh-cut bananas were used as a type of fresh fruit and soaked in 75% hydroalcoholic gels containing salicylic acid (SA) or SA/β-CD inclusion complex (SA/β-CD). After treatment, they were placed in an atmosphere at 85% relative humidity at 20 °C for 12 days. A significant reduction in spoilage in bananas treated with the hydroalcoholic gels in the presence of SA/β-CD was observed, compared with those treated with gels in the presence or absence of SA. The free-radical-scavenging performances of SA and its complex were investigated using the DPPH (1,1-diphenyl-2-picryl-hydrazil) method. Based on the results, the significant increase in antioxidant activity was attributed to the fact that the inclusion complex could break the intramolecular hydrogen bonding of SA, thus efficiently eliminating ROS in the fruits. The formation of the inclusion complex was confirmed by experiments and theoretical calculations. Our findings indicate that treatment with SA/β-CD can provide an efficient method of maintaining postharvest quality and extending the shelf life of bananas.

Effect of Gum Arabic and Starch-Based Coating and Different Polyliners on Postharvest Quality Attributes of Whole Pomegranate Fruit

This study investigated the effect of gum Arabic and starch-based coating and two polyliners (Liner 1-micro-perforated Xtend® and Liner 2-macro-perforated high-density polyethylene) on whole ‘Wonderful’ pomegranate fruit during cold storage (5 ± 1 °C and 95 ± 2% RH). Uncoated (UC) and coated (GAMS) fruit were packaged into standard open top ventilated cartons (dimensions: 0.40 m long, 0.30 m wide and 0.12 m high) with (GAMS + Liner 1, GAMS + Liner 2, UC + Liner 1 and UC + Liner 2) or without (UC and GAMS) polyliners. After 42 d, treatment GAMS + Liner 1 recorded the least weight loss (4.82%), whilst GAMS recorded lower (8.77%) weight loss than UC + Liner 2 (10.07%). The highest (24.74 mLCO2 kg−1h−1) and lowest (13.14 mLCO2 kg−1h−1) respiration rates were detected in UC and GAMS + Liner 1, respectively. The highest and lowest total soluble solids were recorded for GAMS (16.87 °Brix), and GAMS + Liner 1 (15.60 °Brix) and UC + Liner 1 (15.60 °Brix), respectively. Overall, no decay was detected for coated fruit packaged with either Liner 1 or Liner 2. Therefore, the combination of GAMS with Xtend® polyliners proved to be an effective treatment to maintain the quality of ‘Wonderful’ pomegranates during storage.

The Development of a Green Innovative Bioactive Film for Industrial Application as a New Emerging Technology to Protect the Quality of Fruits

Today, the most significant challenge encountered by food manufacturers is degradation in the food quality during storage, which is countered by expensive packing, which causes enormous monetary and environmental costs. Edible packaging is a potential alternative for protecting food quality and improving shelf life by delaying microbial growth and providing moisture and gas barrier properties. For the first time, the current article reports the preparation of the new films from Ditriterpenoids and Secomeliacins isolated from Melia azedarach (Dharek) Azadirachta indica plants to protect the quality of fruits. After evaluating these films, their mechanical, specific respirational, coating crystal elongation, elastic, water vapor transmission rate (WVTR), film thickness, and nanoindentation test properties are applied to apple fruit for several storage periods: 0, 3, 6, 9 days. The fruits were evaluated for postharvest quality by screening several essential phytochemical, physiological responses under film coating and storage conditions. It was observed that prepared films were highly active during storage periods. Coated fruits showed improved quality due to the protection of the film, which lowered the transmission rate and enhanced the diffusion rate, followed by an increase in the shelf life. The coating crystals were higher in Film-5 and lower activity in untreated films. It was observed that the application of films through dipping was a simple technique at a laboratory scale, whereas extrusion and spraying were preferred on a commercial scale. The phytochemicals screening of treated fruits during the storage period showed that a maximum of eight important bioactive compounds were present in fruits after the treatment of films. It was resolved that new active films (1–5) were helpful in the effective maintenance of fruit quality and all essential compounds during storage periods. It was concluded that these films could be helpful for fruits growers and the processing industry to maintain fruit quality during the storage period as a new emerging technology.

Sodium Nitroprusside Functions in Browning Control and Quality Maintaining of Postharvest Rambutan Fruit

Surface browning after harvest is the primary constraint affecting the storage life and market circulation of rambutans. In this study, rambutan fruits were soaked in sodium nitroprusside at different concentrations and stored at 25°C for 8 days to explore the effects on postharvest quality and browning. The weight loss, browning index and superoxide anion radical, hydrogen peroxide and malondialdehyde contents of the treated fruits were reduced compared to those of the control fruits (soaked in distilled water). And fruits treated with sodium nitroprusside had a higher total phenolic content and lower polyphenol oxidase and peroxidase activity. In addition, compared with the control, the treated fruits exhibited higher phenylalanine ammonia lyase, ascorbate peroxidase and superoxide dismutase activities; titratable acidity; and soluble solid, vitamin C and protein contents, indicating high fruit quality. Overall, sodium nitroprusside treatment at 200 μmol L−1 demonstrated the most positive preservation effects. Therefore, sodium nitroprusside treatment, particularly at 200 μmol L−1, can be used as an eco-friendly, safe and convenient method for postharvest quality management and high-efficiency preservation of rambutan fruits.

Evaluation of postharvest storability of Ponkan mandarins stored at different temperatures

ABSTRACT The effects of storage temperature on postharvest storability, quality attributes and antioxidant enzyme activities of harvested Ponkan mandarins were investigated. Fresh fruits were randomly divided into four groups and stored at different temperatures [5 ± 1 °C (S5), 10 ± 1 °C (S10), 15 ± 1 °C (S15), and 20 ± 1 °C (S20 or control)] for 120 days. The results indicated that, compared with the control fruit, low-temperature storage at 10 °C significantly delayed the increase in fruit decay rate, weight loss, citrus colour index, respiration intensity, relative electrical conductivity, the accumulation of hydrogen peroxide and malondialdehyde, retarded the decline in L* value, retained high contents of total soluble solid, titratable acid, vitamin C, total phenol and total flavonoid, as well as higher activities of antioxidant enzymes – superoxide dismutase, catalase, peroxidase and ascorbic peroxidase. The principal component analysis results showed that low-temperature storage significantly maintained the postharvest quality of Ponkan mandarins, with fruit stored at 10 °C having no significant difference from the fruit stored at 5 °C, but markedly higher than those fruit stored at 15 °C. The comprehensive result of single-factor analysis and PCA showed that 10 °C could be used as the optimum storage temperature for improving the postharvest storability of Ponkan mandarins.