Incidence Of Flesh Browning Research Articles

Preharvest 1-methylcyclopropene (1-MCP) treatment effects on quality of spot and strip picked ‘Gala’ apples at harvest and after storage as affected by postharvest 1-MCP and temperature conditioning treatments

‘Gala’ apples are susceptible to development of stem-end flesh browning and subsequently flesh browning (FB) throughout the fruit during storage. Factors causing the browning are not well understood. In this study, fruit were obtained from an orchard block either untreated or treated with preharvest 1-methylcyclopropene (1-MCP; Harvista™) at two different harvest dates, one week apart. Preharvest 1-MCP was applied 7 d before the first harvest. Based on the commercially acceptable red coloration (66%), fruit were spot picked at the first harvest date, stripped picked at the second harvest date, or the remaining fruit from the first spot pick harvested on the second harvest date. Fruit were then untreated or treated with 1-MCP after overnight cooling to 0.5 °C (no conditioning treatment) or 10 °C for temperature conditioning (10 °C for 7 d), followed by storage in 2 kPa O2/2 kPa CO2 at 0.5 °C for 6 months. Fruit were generally less mature when harvested at H1 (spot pick) than at H2 (spot or strip pick), and with preharvest 1-MCP than without, and had the lowest FB incidence after storage. The picking method did not affect fruit maturity or FB incidence, but strip picked fruit softened more in storage than selective picked fruit. Overall, FB incidence was reduced by 5.9-, 1.2- and 1.6-fold by preharvest 1-MCP, postharvest 1-MCP and by conditioning, respectively. IAD values (higher values reflect higher chlorophyll concentrations) at harvest were positively correlated with flesh firmness, and negatively correlated with FB incidence. Preharvest 1-MCP treatment and early harvest contributes to reduced risk of FB development during storage of ‘Gala’ apples.

EFFECT OF TEMPERATURE AND 1-METHYLCICLOPROPENE ON THE STORABILITY OF ‘ALEXANDER LUCAS’ PEAR

ABSTRACT The storage life of ‘Alexander Lucas’ pear is limited by the occurrence of internal storage disorders during controlled atmosphere (CA). 1-Methylcyclopropene (1-MCP) can be used to delay pear ripening, however, its interaction with CA conditions is not well understood. ‘Alexander Lucas’ fruit were treated with 1-MCP at 300 nL L-1 for 24 h in air at-0.5 or 1.0 °C before being stored. Fruit were kept at-0.5 or 1.0 °C in normal air or CA (2.0 kPa O2 plus <0.7 kPa CO2). After six months of storage, superficial scald did not develop in fruit. The highest incidence of flesh browning (72.2 %) was found in air-stored fruit at-0.5 °C without 1-MCP treatment. Storage in air at 1.0 °C plus 300 nL L-1 1-MCP produced 88.8 % of healthy fruit. In contrast, 1-MCP increased the incidence of flesh and core browning under CA conditions. 1-MCP and CA maintained greener skin color and higher titratable acidity. No significant differences were found for fruit firmness, total soluble solids and ascorbic acid content between the treatments. In conclusion, the quality of ‘Alexander Lucas’ pear was best maintained during six months storage under normal air at 1.0 °C combined with 300 nL L-1 1-MCP treatment.

Relationship between flesh browning and the activities of polyphenol oxidase, peroxidase and phenylalanine ammonia-lyase in feijoa fruit

Flesh browning is the main postharvest disorder limiting the storage life of feijoa fruit produced in southern Brazil. The aim of this study was to evaluate the relationship between the activity of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) and incidence of flesh browning in five Brazilian genotypes of feijoa: cultivars 'Alcântara', 'Helena', 'Mattos' and 'Nonante', and the access 2316. Fruit of all genotypes were harvested at commercial maturity in 2013, and cold stored for 7 and 14 days (4±1°C/90±5% RH), followed by 48 h of shelf life (23±1°C/75±5% RH). The activities of PPO, POD and PAL and incidence of fresh browning were assessed at the harvest and after 7 and 14 days of cold storage (followed by shelf life). On average of all genotypes, the activity of PPO increased 29% from harvest to 7 days of cold storage, and 37% from 7 to 14 days of cold storage. PPO activity after 14 days of cold storage was highest in 'Mattos' and lowest in 'Helena'. POD activity was low in all genotypes and decreased from harvest until 14 days of cold storage. In all genotypes, PAL activity did not change from harvest until 7 days of cold storage but increased from 7 to 14 days of cold storage (by 11-28%) in 'Alcântara', 'Helena' and 'access 2316'. 'Mattos' had the highest PAL activity, which did not change from harvest until 14 days of cold storage. The severity of pulp browning after 14 days of cold storage (followed by shelf life) was higher in 'Mattos', 'Alcântara' and 'access 2316', and lower in 'Nonante' and 'Helena'. The results show that the occurrence of flesh browning in the fruit of feijoa genotypes cultivated in southern Brazil is associated fruit senescence, and related to the increase of PPO and PAL activities during storage (especially of PPO). POD activity was low in all genotypes of feijoa and, therefore, the enzyme seems to have little effect on the internal browning.

‘ROCHA’ PEARS STORED UNDER CONTROLLED ATMOSPHERE WITH ULTRA-LOW AND LOW O2 ASSOCIATED WITH DIFFERENT CO2 LEVELS

ABSTRACT The storage of ‘Rocha’ pears under controlled atmosphere (CA) preserves fruit quality for long periods. However, inadequate CA conditions might impair ripening and lead to flesh browning. This research was carried out to assess the effects of CA with ultra-low (ULO), and low O2 (LO) associated with different CO2 levels on ripening and occurrence of flesh browning in ‘Rocha’ pears. Treatments evaluated were: pO2 = 0.5 kPa (ULO) and pCO2 < 0.03 kPa; pO2 = 1.0 kPa (LO) and pCO2 < 0.03 kPa; pO2 = 1.0 kPa and pCO2 = 1.0 kPa; pO2 = 1.0 kPa and pCO2 = 2.0 kPa; and pO2 = 1.0 kPa and pCO2 = 3.0 kPa. A completely randomized experimental design was used, with four replicates. Fruits were harvested in Vacaria, RS, and stored under five CA conditions during 270 days (-0.5±0.1 ºC and relative humidity of 96±2%). Fruits were assessed after CA storage for respiratory rate, ethylene production, skin color, flesh firmness, texture, titratable acidity (TA), soluble solids content (SSC), sensory attributes, flesh browning incidence and severity and flesh color. Fruits stored under LO with pCO2 < 0.03 kPa had higher flesh firmness and more yellow skin color than fruits stored under other CA conditions. Sensory attributes, SS and TA of fruits were not affected by CA conditions. Fruit stored under LO with pCO2 = 3.0 kPa had the highest incidence (48%) and severity of flesh browning. The pO2 = 0.5 kPa and pCO2 < 0.03 kPa and pO2 = 1.0 kPa and pCO2 = 1.0 kPa conditions are the most suitable for the CA storage of ‘Rocha’ pears.

Escurecimento da polpa em pera ‘Rocha’ influenciado pela composição mineral do fruto e condições de atmosfera controlada

RESUMO O objetivo deste trabalho foi avaliar o efeito de condições de armazenamento em atmosfera controlada (AC) e da composição mineral do fruto sobre ocorrência de escurecimento da polpa em pera ‘Rocha’. Os frutos foram armazenados sob diferentes condições de AC: 0,5 kPa O2 + < 0,03 kPa CO2; 1,0 kPa O2 + < 0,03 kPa CO2; 1,0 kPa O2 + 1,0 kPa CO2; 1,0 kPa O2 + 2,0 kPa CO2 e 1,0 kPa O2 + 3,0 kPa C2. Os frutos foram avaliados quanto à incidência e severidade de escurecimento da polpa após 9 meses de armazenamento (−0,5 ± 0,1 °C e UR de 96 ± 2%). Posteriormente, frutos com e sem a presença do distúrbio foram avaliados quanto às concentrações de Ca, Mg, K, N e as relações K/Ca, Mg/Ca e N/Ca. O armazenamento sob 1,0 kPa O2 + 3,0 kPa CO2 proporcionou aos frutos maior incidência de escurecimento da polpa em relação aos armazenados sob 0,5 kPa O2 + < 0,03 kPa CO2 e 1,0 kPa O2 + < 0,03 kPa CO2, ocasionando ainda maior severidade do distúrbio em comparação às demais condições de armazenamento. Peras com escurecimento da polpa apresentaram menores concentrações de Ca, bem como concentrações mais elevadas de K e maiores relações dos elementos K/Ca, Mg/Ca e N/Ca, comparativamente a frutos sem incidência do dano. Todavia, a análise multivariada de todos esses elementos minerais mostrou que a relação K/Ca foi a mais indicada para discriminar frutos sem e com escurecimento da polpa em peras ‘Rocha’.

QUALIDADE DE PERAS ‘ROCHA’ ARMAZENADAS EM ATMOSFERA CONTROLADA

RESUMOO objetivo deste trabalho foi avaliar o efeito de diferentes condições de atmosfera controlada (AC) e da indução de perda de massa (IPM) sobre a qualidade de peras ‘Rocha’. Frutos provenientes do município de São Joaquim-SC, foram armazenados por oito meses e quinze dias a -0,5±0,1 ºC e UR de 96±1%. Os tratamentos foram constituídos em armazenamento refrigerado (AR; 21,0 kPa de O2 + <0,03 kPa de CO2), bem como de cinco condições de AC: 1,0 kPa de O2 + <0,03 kPa de CO2; 2,0 kPa de O2 + 1,0 kPa de CO2; 1,0 kPa de O2 + 1,0 kPa de CO2; 1,0 kPa de O2 + 2,0 kPa de CO2; e 1 kPa de O2 + 2,0 kPa de CO2 + IPM de 2,6%. O AR propiciou frutos com casca mais amarela, menor teor de sólidos solúveis, menor acidez titulável e baixa aceitação nos testes sensoriais para os atributos de textura e equilíbrio doçura/acidez. Os frutos mantidos em AR e em AC, com pressão parcial de CO2 de <0,03 kPa, apresentaram maior firmeza de polpa e de força para penetração da polpa após sete dias de exposição dos frutos em condições ambiente, não desenvolvendo textura amanteigada, própria para o consumo. Não houve incidência de escurecimento de polpa em nenhuma das condições avaliadas. A IPM de 2,6% não apresentou efeito na qualidade dos frutos. As condições de AC de 1,0 kPa de O2 + 1,0 kPa de CO2 e 1 kPa de O2 + 2,0 kPa de CO2 proporcionam melhor manutenção da qualidade de peras ‘Rocha’, permitindo o amadurecimento normal dos frutos após o armazenamento prolongado.

Amadurecimento e qualidade de ameixas 'Laetitia' tratadas com ácido salicílico e 1-metilciclopropeno

O objetivo deste trabalho foi avaliar o efeito da aplicação de ácido salicílico (AS), isoladamente e em combinação com o 1-metilciclopropeno (1-MCP), sobre o amadurecimento e a qualidade de ameixas 'Laetitia', armazenadas durante 40 dias, sob refrigeração (1 ± 0,1ºC / UR 92 ± 2%). Os tratamentos avaliados foram: controle; 1 mM de AS; 5 mM de AS; 10 mM de AS; e 5 mM de AS + 1-MCP (1 µL L-1). Nos frutos tratados com 10 mM de AS, verificou-se, após a saída da câmara, maior taxa de produção de etileno e incidência de manchas na epiderme, e, após três dias em condição ambiente, maior incidência de degenerescência de polpa. Em frutos tratados com 5 mM de AS, o 1-MCP proporcionou menor produção de etileno e menor incidência de degenerescência de polpa, maiores valores de atributos de textura, além de frutos menos vermelhos. O AS não apresenta efeito sobre a ocorrência de degenerescência da polpa e o amadurecimento de ameixas 'Laetitia', porém, provoca manchas na epiderme, em doses acima de 5 mM. Em frutos tratados com 5 mM de AS, a aplicação de 1-MCP atrasa o amadurecimento e mantém a qualidade da ameixa 'Laetitia'.

Fruit maturity, controlled atmosphere delays and storage temperature affect fruit quality and incidence of storage disorders of ‘Fuji’ apples

The effects of storage temperature, harvest maturity, controlled atmosphere (CA) storage regime, and CA strategies on fruit quality and the incidence of storage disorders during storage of ‘Fuji’ apples [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.] were investigated. Flesh browning incidence was lower in fruit stored at 2°C than at 0°C, but fruit were also softer and had lower titratable acidity (TA) at the higher storage temperature. All subsequent studies were carried out at 0°C. High partial pressures of CO2 (pCO2) of 2.5kPa compared with <1kPa did not consistently affect flesh firmness, soluble solids concentration (SSC), and TA. The incidence of flesh browning was higher in more mature fruit and it was further aggravated by higher pCO2 in the storage atmosphere, irrespective of pO2, while watercore disappearance was more rapid at <1kPa CO2 than at 2.5kPa CO2. Flesh browning was also higher at 1.5kPa CO2 than at <1kPa CO2, although ethylene production was lowest at 1.5kPa pCO2. Stepwise delay of high CO2 or low O2 CA storage did not affect flesh firmness, TA, internal ethylene concentration, respiration rate, and ethylene production, but watercore disappearance was more rapid, compared with standard CA storage at 2 months. Flesh browning was not detected in the stepwise CO2 delayed CA treatment and low CO2 CA storage (<0.2kPa CO2), but a low (<4%) incidence of flesh browning was found in a delayed CA treatment and standard CA storage. These results indicate that ‘Fuji’ apples could be stored at 0°C in 1–2kPa O2/<1kPa CO2 if harvested at less than 190 days after full bloom. Stepwise CO2 delay CA or low CO2 CA storage regimes are recommended to retard the loss of fruit quality factors and reduce development of CA-related storage disorders.

Effects of Hot Water Treatments on Antioxidant Enzymatic System in Reducing Flesh Browning of Persimmon

The flesh browning that appears during commercialization period is the main postharvest disorder that is limiting the market of “Rojo Brillante” persimmon in the Mediterranean area. Previous studies have suggested that mechanical damage suffered by the fruit during packing line operations is the trigger of this alteration when fruit is previously subjected to the required deastringecy treatment. In the present work, the effect of hot water treatments (HWTs) on flesh browning incidence of Rojo Brillante persimmon has been investigated. For that, fruits submitted to the commercial deastringency treatment were hot water treated at 45 °C for 30 min or 50 °C for 20 min and then subjected to different intensity of mechanical damage in packing line. Fruit bathed at 25 °C for 25 min and fruit hand-packed acted as control treatments. Our results confirmed that mechanical damage during packing is a decisive factor in the incidence of flesh browning, and this alteration is found to increase the damage intensity. HWTs significantly alleviated flesh browning disorder by affecting the antioxidative system enzymes; the activity of catalase and ascorbate peroxidase was increased by HWTs while the activity of peroxidases was reduced. No changes were observed in polyphenol oxidase and phenylalanine ammonia lyase activity. Therefore, the application of HWTs may be a useful postharvest technology to reduce flesh browning of persimmon induced by packing line operations.

Relationship between Preharvest Factors and the Incidence of Storage Disorders in 'Fuji' Apples during CA Storage

This study was carried out to evaluate the effect of pre-harvest factors on fruit quality and the incidence of storage disorders in 'Fuji' apple during CA storage. Incidence of storage disorders varied, depending on the growing regions, field conditions, and altitude of the orchards. Results indicated that fruit maturity may play a crucial role in the incidence and severity of flesh browning and watercore. The incidence of these storage disorders increased with fruit maturity until 180 days after full bloom (DAFB). In addition, occurrence of watercore was correlated with the incidence of flesh browning during CA storage. The incidence of flesh browning was positively correlated with the sum of the diurnal temperature range from September through October and amount of precipitation from August to October in 1996-1999 growing years. These results suggested that 'Fuji' apple should be harvested no later than 180 DAFB because the late harvested fruits were prone to development of watercore which was correlated with the incidence of flesh browing during CA storage in Korea.

Involvement of ethylene in browning development of controlled atmosphere-stored ‘Empire’ apple fruit

‘Empire’ apples [ Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.] are susceptible to development of chilling injury, expressed as firm flesh browning, during controlled atmosphere (CA) storage. Because of this susceptibility, fruit are typically stored at 2–4 °C, but the incidence of flesh browning can be increased by 1-methylcyclopropene (1-MCP) treatment at these temperatures. In this study, flesh browning development has been investigated in relationship to ethylene production, internal ethylene concentration (IEC), flesh firmness, total phenolic concentrations, and the activities of polyphenol oxidase (PPO) and peroxidase (POX) in the flesh tissues. Fruit were harvested from two orchards, either untreated or 1-MCP treated, and then stored under CA conditions at either 0.5 or 4 °C. Fruit were removed from storage at 1.5-month intervals for 10.5 months. 1-MCP treated apples were firmer than those of untreated apples, and had lower IECs, at all removals. Flesh browning incidence and severity developed earlier in 1-MCP-treated apples than untreated apples stored at either temperature. Total phenolic concentrations differed by orchard, but no major differences in concentrations were detected between untreated and 1-MCP treated apples. However, PPO activities were higher in the flesh of 1-MCP treated apples than untreated apples from both orchards and at both storage temperatures. POX activity was not consistently affected by 1-MCP treatment or storage temperature. Overall, our results suggest that inhibited ethylene production, either as a result of storage at 0.5 °C, or by treatment with 1-MCP at either temperature, may cause stress and damage to cells and result in higher PPO activity that leads to progressive flesh browning development during CA storage.

Carbon Dioxide-induced Flesh Browning in Pink Lady Apples

To investigate a flesh browning (FB) disorder in Pink Lady apple [Malus ×sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. cv. Cripps Pink], fruit were harvested from the same orchard each year from 2002 to 2005, at two or three maturity stages each year. Fruit were kept in air or controlled atmosphere (CA) storage (1.5- to 2-kPa O2 in combination with 1-, 3-, or 5-kPa CO2) at 0.5 °C. Additional subsets of fruit were exposed to 1 μL·L−1 1-methylcyclopropane (1-MCP) for 24 hours and dipped in 2200 μL·L−1 diphenylamine (DPA) for 5 min or held in air at 0.5 °C for 2 or 4 weeks before CA storage. Flesh browning was not seen in air-stored fruit but appeared in CA-stored fruit as soon as 2 months after harvest. Flesh browning incidence did not increase after longer storage times. Flesh browning increased with increasing CO2 concentration and decreasing O2 concentration in storage. 1-MCP did not significantly affect FB incidence, while delaying CA by 2 or 4 weeks reduced it. Diphenylamine eliminated FB incidence. When similar storage atmospheres were compared for the four seasons, FB incidence was high in 2002 and 2004 and low in 2003 and 2005. Concentrations of B, Ca, and Mg in apple flesh and seasonal field temperatures during the growing and harvest periods were related to FB incidence in 2002, 2003, and 2004 but not in 2005. The relationship of these pre- and postharvest factors to FB susceptibility are discussed.

The effect of postharvest calcium application on tissue calcium concentration, quality attributes, incidence of flesh browning and cell wall physicochemical aspects of peach fruits

The effects of postharvest calcium applications on cell wall properties and quality attributes of peach fruits ( Prunus persica L. Batsch, cv. ‘Andross’) after harvest or cold storage up to 4 weeks were determined. The fruits were immersed in deionised water or in different calcium sources (calcium chloride, calcium lactate and calcium propionate) at two calcium concentrations (62.5 and 187.5 mM Ca). Calcium concentration profiles in fruits (peel and flesh), in cell wall and in pectin fractions were determined. The calcium content in the peel increased up to 2.7-fold, whereas flesh calcium increased up to 74%, 1 day after immersion. The increase of flesh calcium was accompanied by increase of cell wall calcium, which corresponded to a significant increase of calcium in the water-insoluble pectin fraction. However, calcium became saturated in the water-insoluble, but not water-soluble, pectin fraction with 62.5 mM Ca treatment. Treatment with 62.5 mM Ca salts was as effective as higher concentrations of calcium chloride maintaining tissue firmness during storage. Inversely, calcium lactate and calcium propionate at high concentrations (187.5 mM Ca) caused toxicity symptoms on the fruit surface, expressed as skin discoloration and superficial pitting, leading to additional chemical changes and reduced tissue firmness. Postharvest calcium applications limited the intense of chilling injury symptoms, expressed as flesh browning after 4 weeks cold storage. Peach fruits with severe flesh browning symptoms were characterized by reduced ethylene production, and reduced activities of the pectin modifying enzymes poly-galacturonase and pectin-methyl-esterase.

CONTROLLED ATMOSPHERE-INDUCED INTERNAL BROWNING IN PINK LADY™ APPLES

Apple (Malus domestica Borkh, Pink Lady ) fruit were harvested from one Californian orchard in 2002 and 2003 at two and three different maturity stages, respectively. Fruit were immediately stored at 0.5°C in air or in controlled atmosphere (CA), 1, 3 and 5% CO 2 in combination with 1.5, 3 and 21% O 2 in 2002 and 1 and 3% CO 2 with 2% O 2 in 2003. Additional treatments in 2003 included 1ppm of 1-methylcyclopropane (1-MCP) for 24 h, 2200 ppm of diphenylamine (DPA) for 5 min and delayed CA storage at 0.5°C for two or four weeks. The area of flesh browning (FB) was determined after storage in CA or air and 5 days at 20°C. IB was not seen in fruit stored in air. It appeared in fruit after two months storage in CA, and the incidence did not increase after longer storage times. There was no significant effect of maturity at harvest on the incidence of FB; however, FB increased with increasing CO 2 concentrations and decreasing O 2 concentrations in storage. 1-MCP and 2 and 4 weeks delayed CA did not significantly inhibit the incidence of FB while DPA inhibited it completely. When comparing similar storage atmospheres for both seasons, the FB incidence was significantly different, being much higher in 2002. A mineral analysis of the apple flesh showed differences among the two seasons. Concentrations of NH 4 , B, Zn, Ca, and Mg were significantly higher and Fe was significantly lower in 2003 corresponding with a lower incidence of FB.

EFFECTIVENESS OF 1-MCP ON POSTHARVEST DETERIORATION OF NECTARINES AND PEACHES STORED AT DIFFERENT TEMPERATURES

Abstract Flesh browning, mealiness and softening are the main causes of postharvest deterioration of peaches and nectarines. The gas application of three concentrations of 1Methylcyclopropene (1-MCP) (0.5; 1.0; 1.5 g/m) was evaluated on one peach (‘September Sun’), and two nectarine (‘Arctic Snow’ and ‘Flamekist’) cultivars stored for 17, 23 and 34 days at 0, 5 and 10°C. The gas was applied at 20 °C for a period of 48 hours and the different concentrations were compared with a delay cooling process done under the same conditions and with control fruit where the fruit were cooled rapidly. High incidence of flesh browning and mealiness was obtained with all the cultivars after 23 days of storage at 0 and 5°C, otherwise total reduction was attained at 10°C but with a high rate of fruit softening. 1-MCP did not reduce fruit softening at 10°C. Delay cooling reduced the incidence of mealiness in all the cultivars after 17 days of storage at all the temperatures evaluated, but high rate of softening was obtained. Although 1-MCP maintained fruit firmness, the combination with the delay cooling procedure reduced the effectiveness of the later to avoid mealiness. The best result of delay cooling and 1-MCP treatments was obtained with ‘Arctic Snow’ cultivar with the lowest concentration of 1-MCP evaluated.

Postharvest Performance of `Elegant Lady' Peach Grown with Different Nitrogen Sources

Fruit quality, storage potential, and consumer acceptance were evaluated for `Elegant Lady' peach fruit from non-conventional and conventional fertilizer management systems. Conventional treatments were fertilized with synthetic sources of nitrogen (ammonium nitrate), while the non-conventional plots received organic sources of nitrogen such as vetch cover, biosolids compost, grass compost, chicken manure, or steer manure. Fertilization treatments were applied at high (300 N unit per acre) and low rates (100 N unit/acre) 2 years before the first postharvest evaluation. Evaluations were carried out for three seasons. There were no significant differences in fruit firmness (N) measured at different fruit positions, soluble solids concentration (%), pH, titratable acidity (% malic acid), water loss susceptibility (%), rate of softening, red color (%), or inking incidence. The incidence of flesh browning, mealiness, and flesh bleeding was only related to storage time and not to the fertilizer source. Therefore, the storage potential was not affected by the nitrogen fertilizer source. In our in-store consumer preference test during the 1995 season, 950 consumers did not perceive any taste differences between fruit from the different nitrogen fertilizer sources. Despite this, consumers still would prefer to buy fruit produced using an organic source of nitrogen rather than synthetic sources.

Effects of Some Postharvest and Storage Treatments on the Incidence of Flesh Browning in Controlled-atmosphere-stored ‘Delicious’ Apples

Abstract Results from a 4-year study indicate that flesh browning in CA-stored ‘Delicious’ apples (Malus domestica Borkh.) is a low-temperature disorder. Little or no flesh browning occurred at storage temperatures of 2°C or higher. Prestorage treatments which reduced flesh browning were dips in calcium and diphenylamine solutions, delays at 20° prior to storage, and exposure to 38°. Gibberellic acid dips had no effect on the disorder. Less flesh browning was found in a 1% CO2 than in a 1.7% CO2 atmosphere at −0.5°, but little effect was observed from CO2 concentration at a 2° storage temperature. The disorder was more prevalent with advanced maturity of the fruit. Regression analysis of variables evaluated at or before harvest showed that increased fruit size, and to a lesser extent the presence of watercore, were important factors in development of flesh browning.

EFFECTS OF SURFACE SOIL PH ON SOIL CATION CONTENT, LEAF NUTRIENT LEVELS AND QUALITY OF APPLES IN BRITISH COLUMBIA

’Starkrimson’ Delicious (Malus domestica Borkh.), 10–15 yr old, on seedling rootstock, were sampled in several orchards, selected for uniformly low soil pH (&lt; 5.0), medium pH and high pH (6.5–7.3). Harrold Red Delicious, 20–25 yr old, were sampled in 18 orchards which had low, medium and high pH within each. Soils with low pH were generally characterized by higher exchangeable Mn and lower exchangeable Ca. Exchangeable soil Mg and K levels were not significantly related to soil pH. On soils of low pH, higher leaf Mn was the main plant nutrient response with both Harrold Red and Starkrimson trees. Significantly decreased leaf Ca was observed on the younger Starkrimson trees at low soil pH. Soil pH had no direct effect on fruit firmness, soluble solids, juice acidity, or flesh Ca, Mg and K contents. Poststorage fruit quality problems were primarily surface scald and were not related to differences in soil pH. Incidence of flesh browning was, however, related to low flesh Ca content.