Fruit Quality of Grafted Watermelon (Citrullus lanatus): Relationship between Rootstock, Soil Disinfection and Plant Stand

Grafting of vegetable transplants is a unique horticultural technology, which was adapted from the practice in perennial crops. However, rootstock/scion combinations may affect and alter the final size, yield, and quality of fruits of grafted plants, both immediately postharvest and during prolonged storage. We evaluated the effect of two rootstocks [TZ148 and Nurit (commercial Cucurbita spp. hybrids)] grafted on one scion (seedless watermelon cv. 1262) in two plant stands (2500 and 5000 plant ha-1), on plant viability, number of marketable fruits (fruits weight above 5 kg) and fruit quality after one week storage at 20°C, in non- or disinfested soil. Soil disinfection significantly improved the viability of non-grafted plants. All grafted plants significantly performed better vine vigor, with no wilt or vine decline symptoms, in either disinfested or non-treated soil, regardless of the type of the rootstock. Plant stand did not affect plant viability. The number of marketable watermelon fruits per m2 was 75 to 700% higher in grafted plants than in non-graft ed. Grafting on Nurit produced significantly more marketable fruits than grafting on TZ148. The quality of fruits harvested from grafted plants was significantly better than non-grafted fruit in both plant stands and soils. Watermelons harvested from Nurit-grafted plants had better taste and texture and almost seedless compared to control and TZ-148-grafted plant

Effect of 1-methylcyclopropene on the antioxidant capacity and postharvest quality of tomato fruit

Tomato fruits ‘1402’ were harvested at mature green (MG), light pink (LP) and light red (LR) stages and treated with 0.3 μL L-1 of 1-methylcyclopropene (1-MCP) at 20°C for 24 h to investigate the ability to retard tomato fruit ripening. The treated and control fruit were stored at 5°C and 12 oC for 14 days and a further 4 days at 20oC for a shelf life period. The results show that the effects of 1-MCP on fruit ripening were related to the stage of maturity and storage temperature. The MG stage was the optimal stage for 1-MCP treatment when fruit storage was at 12°C. 1-MCP treatment reduced the lipophilic antioxidant activity (LAA) of the tomato fruit, but the hydrophilic antioxidant activity (HAA) remained similar to that observed at harvest. 1-MCP is a potential tool for extending shelf life, delaying tomato fruit ripening (slowing color development and firmness loss) and enhancing quality of tomatoes.Keywords: Tomato, 1-MCP, storage, stage of maturity, temperatureAfrican Journal of Biotechnology Vol. 12(6), pp. 547-55

Extended Storage of Yellow Pepper Fruits at Suboptimal Temperatures May Alter Their Physical and Nutritional Quality

Yellow sweet peppers (Capsicum annuum L. cv. Dinamo) are generally more susceptible than red sweet peppers to physiological and pathological deterioration after harvest. Yellow peppers also fetch higher prices at market. In this study, we examined the external and nutritional quality attributes of yellow pepper fruits stored at suboptimal temperatures of 1.5 and 4 °C for 3 weeks, followed by a 3-day shelf-life simulation. Notably, yellow peppers kept in plastic (Xtend®, Stepac, Tefen, Israel) bags at 4 °C maintained their external quality just as well as peppers stored at the optimum temperature of 7 °C. In addition, nutrient content (namely ascorbic acid) and total phenolic and hydrophilic antioxidant contents were not reduced when the peppers were kept at suboptimal storage temperatures of 4 or 1.5 °C in Xtend® plastic packaging. Thus, the external and nutritional qualities of yellow pepper fruits can be preserved at suboptimal temperatures of 4 °C with Xtend® plastic packaging. This is particularly significant in light of the fact that storage at such temperatures is sometimes used as a quarantine method to eliminate pests on produce imported into Israel

The Potential Use of Hot Water Rinsing and Brushing Technology to Extend Storability and Shelf Life of Sweet Acorn Squash (Cucurbita pepo L.)

Acorn squash fruits (Cucurbita pepo L.) are very sweet and are an excellent source of nutrients and vitamins. Very little information is available about their optimal storage temperature or how to extend their shelf life. The present goal was to elucidate the best storage temperature of this fruit, and to evaluate hot water rinsing and brushing (HWRB) technology to maintain fruit quality for several months. The optimal storage temperature was found to be 15 °C. However, treating the fruits with HWRB at 54 °C for 15 s and then storing them at 15 °C significantly maintained fruit quality for 3.5 months, as indicated by higher fruit firmness, lower decay incidence, and improved retention of green skin color

Total antioxidant activity (TAA) of bell pepper during prolonged storage on low temperature

Bell pepper (Capsicum annum L.) is a vegetable known for its antioxidant content, highly important for its nutritional values. The total antioxidant activity (TAA) of pepper fruits is measured by TEAC (Trolox equivalent antioxidant capacity). This assay measures both the hydrophilic (HAA) (vitamin C) and lipophilic (LAA)(carotenoids and vitamin E) contents based on the total radical scavenging capacity and the ability of a scaverenge the stable ABTS radical (ABTS + ) described by Vinocur and Rodov (2006). Fruit were cleaned and disinfected with hot water by rinsing and brushing (HWRB) at 55°C as it is described by Fallik et all ., (1999). Tap water wash was served as control. Fruit were stored at 2°C or 7°C during 3 weeks plus 3 days at 20°C (shelf life simulation). TAA in red bell pepper, immediately after harvest, was 4.29 (0.74 lipophilic and 3,55 hydrophilic) mol TE/g fr.wt. After 3 weeks storage at 2°C, TAA in pepper with cold wash treatment was 4.14 and 3.97 TEAC mol TE/g fr.wt. in HWRB treatment. After 3weeks +3days shelf life on 20°C TAA slowly growing up and obtained content of 5.24 in cold wash and 5.16 TEAC mol TE/g fr.wt. in HWRB. This is mainly due to changes in the lipophilic activity-LAA (treatment with cold water-1.79 and 1.81 mol TE/g fr.wt. in HWRB, comparing with 0.74 mol TE/g fr.wt. on beginning of storage). Hydrophilic antioxidant activity-HAA remains practically unchanged. In fruit, stored at 7°C, pepper ripeness has been associated with carotenoids accumulation especially after shelf life, TAA was 5.33 TEAC ( LAA 2.03) mol TE/g fr.wt

Effects of cold post-harvest treatments of sweet bell peppers on the development of the Mediterranean fruit fly (Ceratitis capitata)

We investigated the survival of Mediterranean fruit fly (Medfly) larval stages on yellow peppers stored for 21 d in cold environments (1.5, 4 and 7 °C), and the differences in larval mortality rates of Medflies exposed to 1.5 °C storage environments between yellow and red peppers. In addition, we investigated the effect of packing yellow peppers and exposing them to cold environments for 21 d on the quality of the fruits. The aim of the study was to investigate packing and shipping post-harvest protocols as a preliminary investigation to explore cold environments as a system to assure the export of quality peppers with low risks of surviving Medfly immature stages. This exploratory study showed that storing yellow peppers for 21 d in lined boxes (20-μm-thick macroperforated Xtend film) at 1.5 and 4 °C protected the quality of the fruit, and precluded the survival of Medfly eggs and larval stages (L1, L2 and L3). In contrast, peppers stored at 7 °C for 21 d did not completely kill immature stages of the Medfly. In addition, the study showed that Medfly larval stages exposed to 1.5 °C environments on yellow and red peppers have different tolerances to cold. Sensitivity to cold in red pepper was higher than in yellow for all larval stages. In addition, sensitivity to cold between larval stages varied between yellow and red peppers: for yellow, sensitivity preceded as follows L1 > L2 > L3, while in red peppers it was L2 > L1 > L3. Abilities to accumulate lipids and protein by feeding Medfly larvae suggest that palatability and nutrition may be partially responsible for the differences in cold tolerance.7 page(s

How Water Quality and Quantity Affect Pepper Yield and Postharvest Quality

There are gaps in our knowledge of the effects of irrigation water quality and amount on yield and postharvest quality of pepper fruit (Capsicum annuum L.). We studied the effects of water quality and quantity treatments on pepper fruits during subsequent simulated storage and shelf-life. Total yield decreased with increasing water salinity, but export-quality yield was not significantly different in fruits irrigated with water of either 1.6 or 2.8 dS/m, but there was a 30–35% reduction in export-quality yield following use of water at 4.5 dS/m. Water quantity hardly affected either total or export-quality yield. Water quality but not quantity significantly affected fruit weight loss after 14 days at 7 °C plus three days at 20 °C; irrigation with water at 2.8 dS/m gave the least weight loss. Fruits were significantly firmer after irrigation with good-quality water than with salty water. The saltier the water, the higher was the sugar content. Vitamin C content was not affected by water quality or quantity, but water quality significantly affected antioxidant (AOX) content. The highest AOX activity was found with commercial quality water, the lowest with salty water. Pepper yield benefited by irrigation with fresh water (1.6 dS/m) and was not affected by water quantity, but post-storage fruit quality was maintained better after use of moderately-saline water (2.8 dS/m). Thus, irrigation water with salinity not exceeding 2.8 dS/m will not impair postharvest quality, although the yield will be reduced at this salinity level

Quality and Storability of Trellised Greenhouse-Grown, Winter-Harvested, New Sweet Acorn Squash Hybrids

Acorn squash (Cucurbita pepo) is a familiar fruit vegetable in North America, appreciated for its attractive appearance, good flavor, nutritional content and long storage life. A breeding program in Israel has produced three new acorn squash hybrids of enhanced sweetness and flavor. Presently, we evaluated productivity, quality, and storability of these new cultivars in fall plantings. The plants were grown trellised, in an insect-proof greenhouse, for fruit production during the winter to meet consumer demand. The plants were highly productive and bore fruits of superb quality, but there was a high incidence of fungal rots during postharvest cold storage. Pre-treating the fruits with hot water brushing and rinsing before storage was found effective in reducing rot incidence of the fruits stored at 15 °C, but only for one cultivar. Storing the fruits at 10 °C with reduced humidity (Rh 70%) enabled a 3-month shelf life with significantly reduced fruit-rot incidence and minimal effect on fruit quality of all three cultivars. Storage at 20 °C with reduced humidity was suitable for a 1-month period. These protocols for prolonging storage life will help attain controlled, gradual year-round marketing of quality acorn squash at uniform, reasonable price levels for farmers and consumers, and could facilitate overseas export

Effects of Rootstock/Scion Combination and Two Irrigation Water Qualities on Cherry Tomato Yield and Postharvest Fruit Quality

The aim of this research was to evaluate postharvest cherry tomato (Solanum lycopersicum (L.) Mill.) yield and fruit quality as affected by grafting and irrigation water quality in the desert region of Israel. Tomato plants (scion cv. Lorka) were grafted onto 3 commercial tomato rootstocks (Resistar, Beaufort and TRS2) and were irrigated with 2 water qualities: fresh water (electrical conductivity (EC)-1.6 dS m−1) and salty water (EC-4.0 dS m−1). Fresh water significantly increased fruit yield by an average of 17% and fruit size, regardless of plant grafting and rootstock, but there were no significant differences in fruit size between the water treatments. However, salty water, but not grafting, significantly improved several quality parameters of fruit stored for 12 d at 12 °C followed by 2 d at 20 °C in simulated sea transport of produce from Israel to Europe and marketing. Fruit harvested from plants irrigated with salty water showed higher sweetness, sourness and, especially, better general taste, and significantly reduced off-flavor, compared with those irrigated with fresh water. The combination of ‘Lorka’ on ‘Resistar’ rootstock and resulted in the best external, internal, and sensory quality parameters at the end of storability and marketing simulation, while the lowest-quality parameters were in fruit harvested from ‘Lorka’ on ‘Beaufort’ rootstock