Eleni Tsantili

Changes during development of Tsapela fig fruits

Abstract Growth of a pollinated fig fruit (Ficus carica L. cultivar ‘Tsapela’) in Southern Greece followed a typical double sigmoid curve divided into three phases; I and III with rapid growth rates and II with slow growth. Measurements on whole fruits showed that Phase II was characterized by increased firmness, titratable acidity and total pectin concentration. Acidity and total pectin reached their maxima at the end of Phase II. Concentrations of soluble pectin, glucose, fructose and sucrose remained low up to Phase III. During the rapid growth in Phase III, firmness, titratable acidity and total pectin decreased, whereas soluble pectin, glucose, fructose and sucrose concentration increased considerably. Sucrose was always a minor sugar. Starch was found at very low levels at all measured stages. Flesh colour, measured by a Hunter colour difference meter, showed a consistent increase in “a” value during the entire period of fruit development.

Effects of postharvest calcium treatments on respiration and quality attributes in lemon fruit during storage

Summary The effects of postharvest calcium (Ca) treatments on respiration and quality attributes in ‘Maglino’ lemons, harvested at the yellow-green or light yellow state, were investigated during storage for up to 60 d. Lemons were immersed in solutions of calcium chloride (CaCl2) at concentrations up to 0.36 M, for 25 min. Weight loss (WL) during storage was not affected by Ca treatment in either colour state of fruit. In yellow-green fruit, Ca treatment prevented decreases in firmness and the highest firmness retention was achieved with 0.09 M CaCl2 after 40 d of storage. However, light yellow fruit did not exhibit changes in firmness in relation to storage time or to Ca treatment. In light yellow lemons, Ca treatment promoted the decreases in carbon dioxide (CO2) production by the fruit and prevented decreases in hue angle values in flavedo, but had no effect on the decreased oxygen (O2) consumption by the fruit, on the decreased L* and increased chroma values in flavedo, and on the unchanged pH values, on the increased ascorbic acid concentration (AA), soluble solids content (SSC) and titratable acidity (TA) of juice during storage. Hue angle decreases in flavedo were best prevented with 0.09 M CaCl2.

Root promoting compounds detected in olive knot extract in high quantities as a response to infection by the bacterium Pseudomonas savastanoi pv. savastanoi

Olive knot crude extract has been found to promote rooting in vitro of Koroneiki olive explants. The analysis of this extract revealed the presence of the naturally occurring auxins indole-3-acetic acid (IAA) and indole-3-acetonitrile (IAN) in high quantities. Both auxins were found in higher amounts in the knots, formed in olive shoots after the infection by the bacterium Pseudomonas savastanoi pv. savastanoi, than in healthy shoots. Further research showed that the knots were rich in phenolic compounds and o-diphenols, as well as that they contained higher amounts of oleuropein (an o-diphenol) and another unidentified compound in contrast to healthy shoots. The analysis of polyamines showed higher concentrations of putrescine in the knots than in the healthy shoots, while it was not possible to detect any traces of spermidine or spermine in the olive knot extract. The results suggested a possible role and collaboration of auxins, phenolic compounds and polyamines, such as putrescine, in the root induction procedure of olive explants in vitro. Furthermore, a possible defense mechanism of olive tree against the bacterium was postulated, through the increased production of possible anticipins, like IAN and the unknown phenolic compound.

Effects of two pre-harvest calcium treatments on physiological and quality parameters in 'Vogue' cherries during storage

Summary The effects of two pre-harvest spray treatments with calcium chloride (CaCl2) concentrations up to 58.5 mM on physiological and quality parameters were investigated in ‘Vogue’ cherries during storage from 1 – 23 d in air at 1° – 3.5°C, at 85 – 95% RH, in two experimental years. No foliar or fruit toxicity was observed. Ca-treated fruit showed greater firmness, lower soluble pectin content, more resistance to stem removal, and less stem browning than watersprayed control fruit during storage. Ca spraying had no effect on fruit weight, fruit size, pH, titratable acidity, total soluble solids, Mg content, or peel colour; whereas there was an increase in Ca content and inconsistent changes in malic acid concentrations in fruits measured after 1 d in storage. Ca did not affect carbon dioxide (CO2) production rates, and showed only slight effects on the already low ethylene production rates, and on the low 1-aminocyclopropane-1-carboxylic acid (ACC) content during storage. In conclusion, treatment with 45 mM CaCl2 had positive effects on most of the quality parameters measured, with no negative effect under our particular experimental conditions.

Growth, Nutrient Status, and Biochemical Changes of Sour Orange Plants Subjected to Sodium Chloride Stress

Sour orange is a valuable citrus rootstock. It is characterized as salt tolerant, based mainly on the mineral content of the leaves and roots under saline environment and to a lesser extent based on any biochemical indices. Therefore, the aim of the present experiment was to study both nutrient content and biochemical changes involved in this rootstocks tolerance. One-year-old sour orange (Citrus aurantium L.) trees growing in 5-L pots were subjected to four levels of sodium chloride salinity stress (control, 40 mM, 80 mM, and 120 mM sodium chloride) for 60 days. At the end of the stress period, plant growth was evaluated by measuring leaf, shoot, and root dry weights. Carbohydrates, chlorophylls, lipid peroxidation, and electrolyte leakage were also determined in leaves. Plant nutrient status was evaluated in leaf, shoot, and root samples, and the soil was also analyzed for nutrient content. Leaf sclerophylly indexes were determined to assess water stress induced by salinity. Leaf dry weight was not significantly affected, whereas shoot and root dry weights decreased with salt stress. Soil electrical conductivity and sodium and chloride concentrations increased with increasing salt concentration, whereas available potassium concentration decreased. Salt stress induced a significant accumulation of sodium and chloride in leaves, shoots, and roots. Potassium and phosphorus concentrations in leaves were enhanced under salt stress, whereas inconsistent changes were detected concerning magnesium, zinc, manganese, and copper concentrations. Sucrose and glucose concentrations were significantly reduced under salt stress while fructose concentration did not exhibit significant changes. Chlorophyll concentration was also reduced under stress. Based on lipid peroxidation and electrolyte leakage indexes, cell membrane integrity was maintained. According to leaf characteristics indexes, leaves’ water stress was negligible, even after 2 months under salt stress. Based on the present results, sour orange accumulated significant amounts of sodium and chloride ions, inducing a reduction of growth, possibly through a reduction of carbon assimilation rate under low chlorophyll content, resulting in reduced carbohydrate concentration in the leaves.

Effects of postharvest treatment with N6-benzyladenine on green olive fruit

Summary The effect of N6-benzyladenine (BA) on ripening processes of green ‘Konservolia’ olives harvested in October was investigated. Fruits were treated with BA concentrations up to 100 mg l–1 and held at 12°C and 25°C. The higher temperature accelerated skin colour development and firmness loss and also increased ethylene production and respiration rates. At both temperatures, BA stimulated colour development, ethylene production and respiration rates but did not affect fruit firmness. The results indicate that CKs may only have a regulatory role on some ripening processes, such as on colour development. The BA stimulatory effects on the two physiological responses may indicate general acceleration of metabolism by CKs during ripening rather than the effects being causally connected to colour development.

Short-term treatments with high CO2 and low O2 concentrations on quality of fresh goji berries (Lycium barbarum L.) during cold storage

BACKGROUND Goji berries (Lycium barbarum L.) are functional fruits but are usually marketed as a dried product. The aim of this study was to investigate the storability of fresh goji berries treated with high CO2 and low O2 concentrations before air storage at 1 °C for 21 days. RESULTS Berries harvested without stems were exposed to air (controls) or subjected for 2 days at 1 °C to the following controlled atmosphere (CA) treatments: 21% O2 + 0% CO2 (21+0), 5% O2 + 15% CO2 (5+15), 10% O2 + 10% CO2 (10+10) and 20% O2 + 20% CO2 (20+20). During 14 days of storage, all treatments decreased weight loss, while treatments 5+15 and 20+20 prevented fungal decay. No fermentation was observed. The treatments did not affect color changes, decreases in soluble sugars and increases in total soluble solids, titratable acidity, ascorbic acid, total carotenoids, total phenolics and ferric-reducing antioxidant power (FRAP) during storage, apart from the marginally reduced FRAP by treatment 20+20 on day 7. Treatments 5+15, 10+10 and 20+20 resulted in residual decreases in respiration rates and pH values early during storage. After 14 days of storage, panelists rated the CA-treated samples as sweet, with good acceptance. CONCLUSION Treatments 5+15 and 20+20 showed the best results after 14 days of storage.