Reduction In Titratable Acidity Research Articles

Effect of mineral fertilizers on the taste qualities of apple varieties

This article presents the results of a 3-year research study into the effect of soil and foliar application of nitrogen and potassium fertilizers on the taste qualities of the Veniaminovskoe (Rvi6) and Sinap Orlovskii (3×) apple varieties bred at the Russian Research Institute of Fruit Crop Breeding (VNIISPK). The assumption that varietal features are the most important factor that determines taste was confirmed. In addition, the influence of weather conditions of the growing season on the chemical composition of fruits was observed. Thus, the year of 2019 was characterized by the most favorable weather conditions of the growing season. In August, during fruit ripening, the optimum temperature and humidity regime had a positive effect on the accumulation of soluble solids, sugars, and titratable acids in both varieties under study. However, the varieties responded differently to the same doses of mineral fertilizers. The application of fertilizers had no significant impact on the content of the studied components and the sugar-acid ratio in Veniaminovskoe fruits. Conversely, Sinap Orlovsky was found to be responsive to this agricultural practice. In 2019, the joint application of triple foliar and soil fertilizing using N30K40, N60K80, and N90K120 in various doses had a positive effect on the reduction of titratable acidity in fruits of this variety. As a result, the sugar-acid ratio increased by 1.3–1.9 times. Over the entire study period (2017–2019), a significant decrease in the content of sugars in Sinap Orlovsky fruits was observed in the variant with additional foliar fertilizing compared to the control. During the study period, the high doses of N90K120 nitrogen and potassium fertilizers along with foliar application contributed to a significant increase in the sugar-acid ratio in Sinap Orlovsky fruits, which significantly exceeded the control.

Physicochemical evaluation of coated and interleaved cheeses with films of ripe banana peel and starch enriched with extract of loquat leaves

This study aimed to evaluate the effect of edible coating and films based on ripe banana peel flour and cornstarch, with and without extract of loquat (Eriobotrya japonica) leaves, in sliced and cut mozzarella cheese during 28 days of storage at 4 °C. During storage, weight loss was observed across all treatments. Increase in pH and reduction in titratable acidity during storage were verified for all cheeses, although milder in those treated with edible formulations. The cheeses submitted to coating or film were less moist than the others. Cheeses treated with the formulation containing the extract were less light and had more intense yellowish coloring. The hardness of the evaluated cheeses did not change during storage. Therefore, the use of edible films and coatings of ripe banana peel flour and loquat leaf extract has potential as an alternative material for the conservation of cheeses.

Antioxidant-Incorporated Poly(vinyl alcohol) Coating: Preparation, Characterization, and Influence on Ripening of Green Bananas.

In this study, the gallic acid (antioxidant)-rich leaf extract of Ficus auriculata was incorporated into poly(vinyl alcohol) (PVA) and utilized as a coating to delay the ripening of green bananas. The films exhibited low opacity of 0.86 ± 0.014 for pure PVA (PP) and 0.92 ± 0.019, 0.99 ± 0.020, and 1.18 ± 0.029 for PVA + 1% extract (PE1), PVA + 5% extract (PE5), and PVA + 10% extract (PE10), respectively, indicating excellent transparency. The weight loss was higher in the uncoated group than in any coated fruits. The reduction in titratable acidity and the increase in total soluble sugars were slower in all of the coated samples as compared to the uncoated ones. The fruits without any treatment attained complete maturity on the ninth day where the ion leakage was 85.61 ± 2.33% while that of PP was 56.36 ± 2.95% and those of PE1, PE5, and PE10 remained below 30%. The coated samples showed better retention and consequently slower degradation of chlorophyll. The fruits coated with pure PVA as well as 10% extract-incorporated PVA remained acceptable till day 15, while the ones with 1 and 5% of extract reached full ripeness on day 18. Results of the present investigation suggest that safe, low-cost, and environmentally friendly coatings can improve the shelf life of perishable produces like bananas.

In Vivo Yarrowia lipolytica Fermented Biomass Feed Supplementation for Shrimp and Its Effects Upon Frozen Meat Storage

ABSTRACT In this work, Macrobrachium rosenbergii were supplemented (0%, 3%, 5%, 10%) with fermented biomass of Yarrowia lipolytica in the feed for 50 days, and subsequently, analyses of the fresh carcass were carried out, and a frozen meat storage test was carried out at − 18 ºC during 0, 3, 6, and 9 months of storage. Regarding fresh meat, an increase in humidity and pH was observed. Total lipid content (5 and 10% groups), thiobarbituric acid reactive substances (TBARS) (10% group), and total volatile basic nitrogen (TVB-N) (3 and 5% groups) also increased, while a reduction in titratable acidity (5 and 10% groups) was observed. Furthermore, increased fatty acid (FA) content was observed predominantly in mono- and polyunsaturated FAs in all groups. Significant rises in TBARS and TVB-N were observed during the storage over time. There was an increase in FA concentrations up to 6 months compared to the initial time and decreased at 9 months. The Y. lipolytica biomass at 3 and 5% can be added to the feed to supplement the shrimp diet since these concentrations improved body composition by increasing the content of mono- and polyunsaturated FAs and has not affected the quality parameters of meat during storage.

Effect of gum arabic coating on antioxidative enzyme activities and quality of apricot (Prunus armeniaca L.) fruit during ambient storage.

The effect of gum arabic (GA) coating was studied on apricot fruit at 20±1°C for 8days. GA coating substantially reduced weight loss, disease incidence, malondialdehyde concentration, and hydrogen peroxide compared to the control. GA coating resulted in significantly higher total phenols, ascorbic acid, and antioxidant activity in contrast to the control. GA coating also suppressed cellulase, pectin methylesterase, and polygalacturonase activity in contrast to the non-coated fruit. In addition, GA-coated apricot fruit had substantially higher catalase, peroxidase, ascorbate peroxidase, and superoxide dismutase enzymes activities in contrast with the control. Similarly, GA coating inhibited soluble solids content increase and inhibited the reduction in titratable acidity in coated fruit. The fruit coated with GA coating also had significantly better sensory and overall eating quality compared to the control apricots. In conclusion, GA could be considered an appropriate edible coating for quality conservation of apricots. PRACTICAL APPLICATIONS: Apricot is a well renowned and nutrients rich fruit. However, apricot has comparatively short shelf life potential due to its susceptibility to rapid senescence and deterioration under ambient conditions. GA is an eco-friendly and biodegradable coating which is considered relatively cheap as compared with other coating types. In our present work, application of gum arabic [GA (10%)] edible coating maintained significantly higher quality of harvested apricot fruit as compared with the control. The outcomes of the present work are of global significance with respect to apricot industry. So, GA coating could be considered an appropriate edible coating for quality conservation of the harvested apricot fruit.

Combined effect of hot water dipping and Cistus creticus L. leaf extracts on the storage quality of fresh Valencia oranges

Abstract This research was designed to test the combined efficacy of hot water dipping (HWD) and leaf extracts of Cistus creticus L. subsp. creticus on the storage quality of fresh Valencia oranges. Experiments were laid down according to a completely randomised design with 10 different treatments. Five replications, with five fruits in each replication, were used in the current study, and research was designed to continue for 150 days. Quality characteristics were observed with 30-days interval. The applications of this study were (1) Control [dipping in water at 25°C for 5 min]; (2) HWD at 50°C for 5 min; (3) HWD + Additives (A) [Arabic gum (0.2%), potassium sorbate (0.05%), citric acid (0.05%) and vitamin C (0.05%)] at 50°C for 5 min; (4) Additives alone at 25°C for 5 min; (5) 1.0% C. creticus leaf + HWD + A; (6) 1.0% C. creticus leaf + A; (7) 0.5% C. creticus leaf + HWD + A; (8) 0.5% C. creticus leaf + A; (9) 0.5% C. creticus leaf + HWD and (10) 0.5% C. creticus leaf. According to the results obtained, both the HWD and C. creticus, alone or in combination, were effective in preserving orange weight during storage, preventing pathogenic decay, maintaining visual quality and fruit firmness, delaying the reduction in titratable acidity, increasing ascorbic acid content and reducing respiration rate of the orange fruits. Results also suggested that the combined effect of HWD with C. creticus leaf extracts provided the highest efficacy.

Modeling the Inactivation of Bacillus cereus in Tiger Nut Milk Treated with Cold Atmospheric Pressure Plasma

The impact of cold atmospheric pressure plasma treatment on the inactivation kinetics of Bacillus cereus ATCC 14579 and the resulting quality changes was investigated in tiger nut (Cyperus esculentus L.) milk (TNM). The effect of input power (39, 43, and 46 W) and treatment time (0 to 270 s) was fitted using the Weibull model to represent the microbial kinetic inactivation in the treated TNM. Inactivation efficacy increased with an increase in treatment time and input power. A 5.28-log reduction was achieved at 39 to 46 W without significant changes in titratable acidity, whereas no reduction in titratable acidity was observed in the pasteurized sample. The inactivation kinetics was adequately described by the Weibull model. Higher input power of 43 and 46 W and 120 s of treatment resulted in marked decreases in pH, flavonoid concentration, and antioxidant activity compared with those parameters in pasteurized TNM. Increases in total color difference and phenolic concentrations also were observed. The results indicate that these changes were caused by the immanent plasma reactive species. This study provides valuable inactivation kinetics information for food safety assessment studies of B. cereus vegetative cells in TNM.

Gastro-Protective and Anti-Oxidant Potential of Althaea officinalis and Solanum nigrum on Pyloric Ligation/Indomethacin-Induced Ulceration in Rats.

Recently, an alternative disease treatment approach is the research of medicaments from traditional medicine. Plants with anti-oxidant capabilities are used as herbal treatments for ulcer diseases. Medicinal/herbal extracts containing phytoconstituents have significant anti-ulcer activities in in vivo experiments on animal models, compared to reference drugs. The current study aims to inspect gastro-protective as well as in vitro and in vivo anti-oxidant potential of Althaea officinalis and Solanum nigrum extracts on pyloric-ligation/indomethacin-induced gastric-ulceration in rats. Rats were divided into six groups: normal control, gastric ulcer control, two standard pretreatment groups receiving omeprazole and misoprostol, and two test pretreatment groups receiving Althaea officinalis and Solanum nigrum. Pretreatments were administrated orally for 14 days. On the 15th day, animals, excluding the normal control group, were exposed to pyloric-ligation followed by indomethacin injection. After four hours, the rat’s stomachs were removed and gastric juice and blood samples were collected. Pyloric-ligation/indomethacin administration caused considerable elevation in ulcer number, ulcer index, acid and pepsin productivity, aggressive factors, and gastric mucosal lipid-peroxide contents. Moreover, reduction in titratable acidity, gastric mucosal nitric-oxide, anti-oxidant contents, and protective factors accompanied gastric-ulceration. Additionally, elevation in pro-inflammatory cytokines content and reduction in cystathionine-β-synthase and heme-oxygenase-1 expression was witnessed. Omeprazole, misoprostol, Althaea officinalis, and Solanum nigrum pretreatments fixed blood and tissue biomarkers, thereby protecting them from pyloric-ligation/indomethacin-induced gastric-ulceration in rats, which is hopeful for clinical examinations.

Effects of neem leaf extract and hot water treatments on shelf life and quality of banana

A huge loss of banana occurs due to its shorter shelf life and inappropriate postharvest handling. There is a scarce of effective postharvest practices to combat this situation in Bangladesh. In this context, the current experiment was conducted to assess the effects of hot water (45°C for 2 or 5 minutes) and neem leaf extract (20% or 40%) on quality and shelf life of banana (cv. Sabri). The experiment was carried out in completely randomized design with three replications. Data on physico-chemical properties of banana were collected during storage in ambient conditions for two weeks. After two weeks of storage, the banana treated with 40% neem leaf extract showed longest shelf life (8.33 days), minimum change in color (score 4.88), minimum disease incidence (33.33%) and severity (score 2.23), lower reduction of titratable acidity (0.12%) and lower level of total soluble solid (6.90%). While the banana were treated with hot water at 45°C for 2 min, the treated banana also showed lower color change (score 4.53), longer shelf life (8.33 days), minimum loss of firmness (score 4.67), minimum change in vitamin C content (2.17mg/100g) and lower reduction in titratable acidity (0.11%). Among the combined treatments, the banana treated with the combination of hot water (at 45°C for 5 minutes)and 40% neem leaf extract also exhibited considerably longer shelf life (8.17 days), lower change in color (score 5.00), lower disease incidence (46.67%) and lower reduction in titratable acidity (0.15%). From the study it could be concluded that the fruit treated with 40% neem leaf extract retained the majority of the quality parameters for considerably longer period and thereby it could be recommended for practical use to ensure better and longer storage of banana (cv. Sabri)
 J.Bangladesh Agril. Univ. 16(3): 351–356, December 2018

Comparative analysis of fruit ripening and associated genes in two kiwifruit cultivars (‘Sanuki Gold’ and ‘Hayward’) at various storage temperatures

Kiwifruit exhibit a peculiar ripening pattern, as extensive softening is known to occur in the absence of any detectable ethylene. We previously demonstrated that this softening is regulated by low temperature independent of ethylene. However, there are no reports that provide comparisons of the ripening patterns among different kiwifruit cultivars at various storage temperatures. The purpose of this study was to compare the ripening responses and associated gene expression in ‘Sanuki Gold’ (Actinidia chinensis var. chinensis) and ‘Hayward’ ((Actinidia chinensis var. deliciosa) fruit, two kiwifruit cultivars differing in on–vine maturity dates and postharvest storability, during storage at 5 °C, 10 °C, 15 °C and 22 °C. Fruit softening, soluble solids concentration (SSC) increase and reduction of titratable acidity (TA) occurred in the absence of any detectable ethylene, and treatment with an ethylene inhibitor 1–methylcyclopropene (1–MCP) failed to suppress the changes, suggesting that they were independent of ethylene. ‘Sanuki Gold’ fruit showed a higher sensitivity to low temperature supported by accelerated fruit softening and TA reduction, and induction of several genes such as AcACO3, AcXET2, AcPG, AcEXP1, AcPMEi, AcGA2ox1, AcMADS2, AcNAC5 and AcbZIP2 at 5 °C, 10 °C and 15 °C within 28 d. By contrast, ‘Hayward’ fruit exhibited a lower sensitivity to low temperature as accelerated softening, TA reduction and induction of most ripening–associated genes were recorded only at 5 °C and 10 °C. These differences in sensitivity to low temperature, between ‘Sanuki Gold’ and ‘Hayward’ fruit, would account for the dissimilarities observed in on–vine maturity dates and postharvest storability.

Characterization of Southeast Asia mangoes (Mangifera indica L) according to their physicochemical attributes

Mango (Mangifera indica L.) is an economically important fruit crop grown in the tropics. One of the important traits of mango for successful commercial production is the storage quality of the fruit. This study was conducted to evaluate the postharvest qualities of three mango (Mangifera indica) varieties namely ‘Chokanan’, ‘Golden phoenix’ and ‘Water lily’ grown in Southeast Asia regions. The study found that variety and ripening stage had an impact on the postharvest qualities. In general, an increase in weight loss, L* value and soluble solids concentration (SSC) along with a reduction in titratable acidity (TA), firmness and hue value as ripening progressed were observed irrespective of the variety. Analysis of variance and multivariate analysis were used to characterize the ripening process. This study provides useful information for devising strategies in postharvest handling and implementation of breeding programs for mango crop improvement.

Comparative transcriptome analysis reveals distinct ethylene\u2013independent regulation of ripening in response to low temperature in kiwifruit

BackgroundKiwifruit are classified as climacteric since exogenous ethylene (or its analogue propylene) induces rapid ripening accompanied by ethylene production under positive feedback regulation. However, most of the ripening–associated changes (Phase 1 ripening) in kiwifruit during storage and on–vine occur largely in the absence of any detectable ethylene. This ripening behavior is often attributed to basal levels of system I ethylene, although it is suggested to be modulated by low temperature.ResultsTo elucidate the mechanisms regulating Phase 1 ripening in kiwifruit, a comparative transcriptome analysis using fruit continuously exposed to propylene (at 20 °C), and during storage at 5 °C and 20 °C was conducted. Propylene exposure induced kiwifruit softening, reduction of titratable acidity (TA), increase in soluble solids content (SSC) and ethylene production within 5 days. During storage, softening and reduction of TA occurred faster in fruit at 5 °C compared to 20 °C although no endogenous ethylene production was detected. Transcriptome analysis revealed 3761 ripening–related differentially expressed genes (DEGs), of which 2742 were up–regulated by propylene while 1058 were up–regulated by low temperature. Propylene exclusively up–regulated 2112 DEGs including those associated with ethylene biosynthesis and ripening such as AcACS1, AcACO2, AcPL1, AcXET1, Acβ–GAL, AcAAT, AcERF6 and AcNAC7. Similarly, low temperature exclusively up–regulated 467 DEGS including AcACO3, AcPL2, AcPMEi, AcADH, Acβ–AMY2, AcGA2ox2, AcNAC5 and AcbZIP2 among others. A considerable number of DEGs such as AcPG, AcEXP1, AcXET2, Acβ–AMY1, AcGA2ox1, AcNAC6, AcMADS1 and AcbZIP1 were up–regulated by either propylene or low temperature. Frequent 1–MCP treatments failed to inhibit the accelerated ripening and up–regulation of associated DEGs by low temperature indicating that the changes were independent of ethylene. On–vine kiwifruit ripening proceeded in the absence of any detectable endogenous ethylene production, and coincided with increased expression of low temperature–responsive DEGs as well as the decrease in environmental temperature.ConclusionsThese results indicate that kiwifruit possess both ethylene−dependent and low temperature–modulated ripening mechanisms that are distinct and independent of each other. The current work provides a foundation for elaborating the control of these two ripening mechanisms in kiwifruit.

The effects of cooking time and sugar on total phenols, hydroxymethylfurfural and acrylamide content of mulberry leather (pestil)

The effects of glucose syrup (0, 20, and 40%), sucrose syrup (0, 20, and 40%) and cooking time (10 and 20 min) on the chemical characteristics of mulberry pestil were investigated by replacing glucose syrup and sucrose syrup with mulberry syrup. Changes in glucose and sucrose syrup concentrations significantly affected invert sugar, sucrose and total soluble solids content of mulberry pestils. The invert sugar values of mulberry pestil increased with the addition of glucose syrup, but decreased with the addition of sucrose syrup. An increase in levels of sucrose or glucose syrup resulted in an increase of the lightness of colour values; however, an increase in cooking time reduced the lightness of colour of mulberry pestil. When sucrose and glucose syrup were added, an increase in pH values of samples but a reduction in titratable acidity was detected. Replacing glucose syrup with mulberry syrup in the formulations resulted in a decrease in the amount of hydroxymethylfurfural and acrylamide formed in mulberry pestils. The reducing effect of glucose syrup on hydroxymethylfurfural and acrylamide formation was much greater than the effect of sucrose syrup.

Recobrimentos à base de carboximetilcelulose e dextrina em mangas 'Tommy Atkins' armazenada sob refrigeração

Objetivou-se avaliar a eficiência de recobrimentos à base de carboximetilcelulose (CMC) e dextrina em manga 'Tommy Atkins' armazenada durante zero, dez e 20 dias sob refrigeração (12,4±3,1°C e 72±12% UR) e, posteriormente, submetida às condições de ambiente (20,3±3,0°C e 40±7% UR) por três, seis, oito e nove dias. Os recobrimentos CMC 1,0% + dextrina 0,2%, CMC 0,8% + dextrina 0,5% e CMC 0,5%+dextrina 1,0% foram comparados ao controle. O delineamento experimental foi inteiramente casualizado, em fatorial 4x7 (recobrimento x tempo de armazenamento), com quatro repetições compostas por três frutos. A aplicação de CMC 1,0% + dextrina 0,2% ou CMC 0,8% + dextrina 0,5% retardou o acúmulo de sólidos solúveis, a redução da acidez titulável e a evolução da cor da casca, com incremento no brilho superficial dos frutos, o que garantiu melhor aparência. Os efeitos indicam atraso da maturação, sendo mais evidentes no tratamento CMC 0,8% + dextrina 0,5%.

Effect of zero energy cool chamber and post-harvest treatments on shelf-life of fruits under semi-arid environment of Western India. Part 2. Indian gooseberry fruits

Effect of zero energy cool chamber (ZECC) along with post-harvest treatments including CaCl2, mustard oil and K2SO4 separately on shelf-life and fruit quality attributes of Indian gooseberry or aonla (Emblica officinalis Gaertn) during storage under semi-arid ecosystem of Gujarat was studied. Increase in physiological loss in weight (PLW), spoilage loss, total soluble solids, total sugar and reducing sugars, reduction in titratable acidity and ascorbic acid were observed during storage period in all the treatments. Fruits treated with 1.5% CaCl2 and stored in ZECC recorded least PLW (16%), spoilage loss (16.5%), respiratory activity (83 mg CO2 /kg/h) and exhibited 11 days of shelf-life, while untreated control had 6 days economic life. It was closely followed by 1% CaCl2 + ZECC treatment. Fruits stored in ZECC recorded 9 days shelf-life. Highest respiration rate was in control (88.1 mg CO2 /kg/h) on 13(th) day of storage. It may be concluded that 1.5% CaCl2 and storage in ZECC treatment was found most efficient to retain the fruit quality attributes till 13(th) day of storage under semi-arid environment of western India.

Effect of zero energy cool chamber and post-harvest treatments on shelf-life of fruits under semi-arid environment of Western India. Part 1. Ber fruits

Effect of zero energy cool chamber (ZECC) along with post-harvest treatments (including CaCl2, mustard oil and K2SO4 separately) on shelf-life and fruit quality attributes of ber (Zizyphus mauritiana Lamk.) cv 'Gola' during storage under semi-arid ecosystem of Gujarat was studied. Increase in physiological loss in weight (PLW), spoilage loss, total soluble solids, total sugars, reducing sugar and reduction in titratable acidity, and ascorbic acid during storage were observed in all treatments. Fruits treated with CaCl2 1.5% and stored in ZECC recorded least PLW (17.1%), spoilage loss (20%), respiratory activity (0.25 mg CO2/kg/h) and exhibited 7 days of shelf-life, followed by CaCl2 1% + ZECC, while untreated fruits had 3 days of economic shelf-life. Fruits stored in ZECC recorded 6 days shelf-life. Highest respiration rate was in control (0.45 mg CO2 /kg/h) on 9(th) day of storage. Data on fruit quality attributes indicated that ZECC + CaCl2 1.5% or ZECC alone might be an ideal on-farm storage facility for maintaining the quality of ber fruits under semi-arid environment of Western India.

Beneficial Effect of Selective Virus Elimination on the Performance ofVitis viniferacv. Chardonnay

The effect of selective virus elimination on vigor, yield, and fruit quality of <i>Vitis vinifera</i> cv. Chardonnay was evaluated over six years in a replicate field trial. Test material was propagated from three clones infected by multiple virus combinations (GLRaV-1, GVB, and GRSPaV; GFkV, GLRaV-1, GVB, and GRSPaV; GLRaV-2, GLRaV-3, and GRSPaV) and virus-like diseases (vein mosaic and vein necrosis), and selected progeny were obtained after virus elimination by heat therapy and in vitro apex grafting. Some but not all viruses were eradicated in the progeny subjected to virus elimination, as shown by graft indexing and DAS-ELISA using appropriate γ-globulins, allowing for comparative viticultural performance analysis of clonal material with distinct viral infectious status. Elimination of GLRaV-2 had the highest beneficial impact with a marked increase in cumulative weight growth (21%), fresh fruit yield (22%), and sugar concentration of fruit juice (9%). Selective elimination of GLRaV-1, GLRaV-3, and GVB had also a beneficial impact, with an increase in vigor (0, 6, and 35%, respectively) and production (12, 3, and 16%, respectively), while fruit maturity indices were variably affected (0, 3, and 0% increase in fruit juice sugar and 13, 0, and 0% reduction in titratable acidity, respectively). These results offer new insights into the impact of GLRaV-2 on vigor, yield, and fruit quality of <i>V. vinifera</i> and provide strong evidence for the need to include detection assays for this detrimental virus in certification programs.

EFFECTS OF 1-MCP TREATMENTS ON FRUIT QUALITY AND STORABILITY OF DIFFERENT PEAR VARIETIES

The effects of 1-MCP treatments on 'Williams', 'Bosc' and 'Packhams Triumph' pears (Pyrus communis) stored in controlled atmosphere (CA) were studied. Each variety was harvested at three different stages of maturity (Optimal harvest date (OHD) - 1 week, OHD, OHD + 1 week). After harvesting, the fruits of each stage of maturity were divided in two samples. One part was treated with MCP 625 ppb the other one was untreated. After treatment the samples were stored for approximately 300 days under CA conditions (temperature -0.5°C, O 2 2.5%, CO 2 2.0%). Whereas untreated fruits showed excessive firmness losses and reduction of titratable acidity during shelf-life, 1-MCP delayed softening and stabilised titratable acidity of all tested varieties. These effects depended only on stage of maturity and were not variety-dependent. Fruits in stage of over maturity lost more in firmness and acidity than fruits harvested at their optimal stage of maturity. TTS were not affected by 1-MCP. Fungal decay caused by Penicillium expansum (blue mold decay) and Botrytis cinerea (grey mold decay) was the main problem after long term storage. CA and also 1-MCP were not effective in preventing abundant storage losses caused by excessive fruit rotting. The ability of 1-MCP to reduce fungal decay varied considerably among the cultivars and the stage of maturity. When to late harvested pears were treated with 1-MCP only very little or no response occurred. Treatments with a low dosage of 1-MCP (125 ppb) on pears that were harvested too late showed only very little or no response.

Varietal Differences in the Relationship between Maturation Characteristics, Storage Life and Ethylene Production in Peach Fruit

The time courses of fruit weight, ground color of skin (a value), flesh firmness, sugar content, titratable acidity and amount of ethylene produced were measured during growth, maturation and senescence of four peach cultivars (Prunus persica Batsch) with different keeping qualities. Special emphasis was placed on the relationships and differences among individual indices of maturation and the characteristics of ethylene production. In the melting-type cultivars 'Akatsuki', 'Kushigatahakuto' and 'Nagasawahakuho', increase in fruit size, changes in ground color, rise in sugar content and reduction in titratable acidity gradually proceeded after full bloom. After a cultivar-dependent period, postharvest ethylene production and softening were clearly accelerated. On-tree ethylene production occurred later. However, there were large varietal differences in the relationship between ethylene production and changes in the indices of maturation. In 'Kushigatahakuto', ethylene production and softening proceeded fruit enlargement, completion of changes in ground color, and the rapid rise in sugar content. In contrast, in 'Nagasawahakuho', which showed a slow and late softening, ethylene production started after attaining full size, accumulating near maximum sugar level and loss of ground color. In the stony hard-type cultivar 'Yumyeong', ethylene production and postharvest softening did not occur; the on-tree flesh firmness decreased to about 4.0 kg. However, the trends in increase in fruit size, change in ground color, sugar accumulation and decreased in titratable acidity, were similar to those of the melting-type cultivars. From these results, we conclude that there are large varietal differences in the softening and maturation characteristics of peach fruit and that the genetics is determinant of these differences.

Quality and Shelf Life of Tomatoes Improved by Intermittent Warming

Breaker tomatoes of the long life cultivar ‘Daniela F-1’ Hazera (Lycopersicon esculentum Mill) treated with 1 g/L iprodione, were stored at 6, 9 and 12 °C, and 90–95% RH for 14 and 21 d. Fruit stored at 6 and 9 °C was exposed to intermittent warming at 20 °C for one day, at 7-d intervals. Fruit was then allowed to ripen for a period of 3 d at 20 °C and 75–80% RH. In comparison to continuous storage at 6 or 9 °C, intermittent warming during two or three cycles of 6 d at 6 or 9 °C and 1 d at 20 °C, enhanced the surface colour and encouraged ripening. At the end of cold storage and after post-storage ripening, there was no significant change in the soluble solids content. A slight reduction in titratable acidity was induced by intermittent warming. After ripening, the best results were obtained by intermittent warming during three cycles of 6 d at 9 °C and 1 d at 20 °C. Continuous storage at 12 °C also yielded good results. Both treatments resulted in fruits of acceptable quality and shelf life for commercial purposes. Similar results have already been reported for conventional tomato hybrid plants, indicating that the physiological behaviour of both cultivars were similar under similar intermittent storage temperatures.