Effect of a postharvest treatment with natural fungicides on the epiphytic populations of Geotrichum candidum on nectarines

The sour rot pathogen of peach (Prunus persica var. persica) and nectarine (P. persica var. nectarina) fruit, Geotrichum candidum, can cause significant postharvest losses in California fruit production. Harvested peach and nectarine fruit, treated with fungicide at the packinghouse but culled after inspection because of disease and defects, were collected for further assessment and pathogen isolation. The incidence of fruit with sour rot was 3.4 ± 1.0 to 26.1 ± 2.3%. Culled fruit that had been treated with postharvest fungicides from five different orchards had a significantly higher incidence of sour rot when compared with nontreated fruit. Since August 2006, propiconazole has been used as a postharvest treatment to protect peach and nectarine fruit against sour rot. The mean effective concentration that inhibits 50% of mycelial growth (EC50) value of 57 isolates of G. candidum to propiconazole collected before and during 2006 was 0.072 μg/ml. However, 61 isolates from propiconazole-treated, diseased fruit collected from 2007 to 2009 had a mean EC50 value for mycelial growth of 0.378 μg/ml, a fivefold shift in mean sensitivity. Propiconazole applied as either a protective or curative treatment significantly reduced disease severity and decay development in fruit inoculated with a propiconazole-sensitive isolate. The fungicide was significantly less effective when applied as a preventive or a curative application to fruit that were inoculated with a less-sensitive isolate of G. candidum. Under laboratory conditions, isolates of the pathogen less sensitive to propiconazole were stable over multiple transfers on fungicide-free medium. The potential for the development of G. candidum populations with reduced sensitivity to propiconazole and the increased risk of crop loss due to the practice of returning culled fruit to production orchards are discussed.

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Optimization of pectinase production from Geotrichum candidum AA15 using response surface methodology

Pakistan Journal of Botany ◽

10.30848/pjb2019-2(41) ◽

2018 ◽

Vol 51 (2) ◽

Cited By ~ 4

Author(s):

Asia Ahmed ◽

Muhammad Naseem Khan ◽

Aqeel Ahmad ◽

Shakeel Ahmed Khan ◽

Muhammad Sohail

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Geotrichum Candidum ◽

Pectinase Production

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Biological Processing of Pea Grain and Secondary Starch Raw Materials to Produce Food and Feed Protein Concentrates

Biotekhnologiya ◽

10.21519/0234-2758-2020-36-4-49-58 ◽

2020 ◽

Vol 36 (4) ◽

pp. 49-58

Author(s):

V.V. Kolpakova ◽

R.V. Ulanova ◽

L.V. Chumikina ◽

V.V. Bessonov

Keyword(s):

Saccharomyces Cerevisiae ◽

Amino Acid ◽

Amino Acid Composition ◽

Acid Composition ◽

Mass Fraction ◽

Geotrichum Candidum ◽

Protein Concentrate ◽

Protein Concentrates ◽

Pea Flour ◽

Nitrogenous Substances

The goal of the study was to develop a biotechnological process for the production of protein concentrates via bioconversion of pea flour and whey, a secondary product of starch manufacture. Standard and special methods were used to analyze the chemical and biochemical composition of protein concentrates (amino acid, carbohydrate, and fractional) of flour, whey and protein concentrates. It was established that pea flour contains 52.28-57.05% water-soluble nitrogenous substances, 23.04-25.50% salt-soluble, 2.94-4.69% alcohol-soluble compounds, 0-0.61% of soluble glutenine, 6.67-10.40% alkali-soluble glutenine and 5.96-10.86% insoluble sclerotic substances. A mathematical model and optimal parameters of the enzymatic extraction of pea protein with a yield of 65-70% were developed. Ultrasonic exposure increased the yield of nitrogenous substances by 23.16 ± 0.69%, compared with the control without ultrasound. The protein concentrate had a mass fraction of nitrogenous substances of 72.48 ± 0.41% (Nx6.25) and a complete amino acid composition. The microbial conversion by the Saccharomyces cerevisiae 121 and Geotrichum candidum 977 cultures of starch whey which remained after protein precipitation allowed us to obtain feed concentrates from biomass and culture liquid with a protein mass fraction of 61.68-70.48% (Nx6.25). Protein concentrates positively affected the vital signs of rats and their excretory products. A technological scheme was developed to test the complex pea grain and starch whey processing under pilot conditions. pea, protein concentrate, extracts, whey, bioconversion, Geotrichum candidum, Saccharomyces cerevisiae, chemical composition, amino acid composition

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The role of lipid metabolism and signalling during postharvest treatment and storage of horticultural crops

Stewart Postharvest Review ◽

10.2212/spr.2008.3.7 ◽

2008 ◽

Vol 4 (3) ◽

pp. 1-8

Author(s):

Fernando Alferez

Keyword(s):

Lipid Metabolism ◽

Horticultural Crops ◽

Postharvest Treatment ◽

And Storage

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Paper-containing 1-methylcyclopropene treatment suppresses fruit decay of fresh Anxi persimmons by enhancing disease resistance

Food Quality and Safety ◽

10.1093/fqsafe/fyab007 ◽

2021 ◽

Vol 5 ◽

Author(s):

Lingzhen Zeng ◽

Lili Shi ◽

Hetong Lin ◽

Yuzhao Lin ◽

Yixiong Lin ◽

...

Keyword(s):

Disease Resistance ◽

Decay Rate ◽

Potential Application ◽

Total Phenolics ◽

Lignin Content ◽

Related Substances ◽

Postharvest Treatment ◽

Cent Relative Humidity ◽

Fruit Decay ◽

Fruit Disease

Abstract Objectives The purpose of this work was to evaluate the potential application of papers containing 1-methylcyclopropene (1-MCP) postharvest treatment for suppressing fruit decay of fresh Anxi persimmons and its possible mechanism. Materials and methods Anxi persimmon fruit were treated with papers containing 1-MCP at the dosage of 1.35 μL/L and stored at 25 ± 1 °C and 85 per cent relative humidity for 35 days. During storage, the fruit decay rate and lignin content were evaluated, and the content of total phenolics, the activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), chitinase (CHI), and β-1,3-glucanase (GLU) were determined by spectrophotometry. Results The 1-MCP–treated persimmons displayed a lower fruit decay rate, but higher contents of lignin and total phenolics, higher activities of PAL, PPO, POD, CHI, and GLU. Conclusions The treatment with 1-MCP could inhibit the fruit decay of postharvest Anxi persimmons, which might be because 1-MCP enhanced fruit disease resistance by increasing the activities of disease resistance-associated enzymes and retaining higher contents of disease resistance-related substances in postharvest fresh Anxi persimmons. These findings indicate that papers containing 1-MCP at the dosage of 1.35 μL/L have potential application in suppressing fruit decay and extending storage life of postharvest fresh Anxi persimmons.

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Quantitative Characterization of Geotrichum candidum Growth in Milk

Applied Sciences ◽

10.3390/app11104619 ◽

2021 ◽

Vol 11 (10) ◽

pp. 4619

Author(s):

Petra Šipošová ◽

Martina Koňuchová ◽

Ľubomír Valík ◽

Monika Trebichavská ◽

Alžbeta Medveďová

Keyword(s):

Growth Parameters ◽

Mechanistic Model ◽

Geotrichum Candidum ◽

Activity Level ◽

Effect Of Temperature ◽

Operational Parameters ◽

Quantitative Characterization ◽

Essential Knowledge ◽

Cardinal Temperatures

The study of microbial growth in relation to food environments provides essential knowledge for food quality control. With respect to its significance in the dairy industry, the growth of Geotrichum candidum isolate J in milk without and with 1% NaCl was investigated under isothermal conditions ranging from 6 to 37 °C. The mechanistic model by Baranyi and Roberts was used to fit the fungal counts over time and to estimate the growth parameters of the isolate. The effect of temperature on the growth of G. candidum in milk was modelled with the cardinal models, and the cardinal temperatures were calculated as Tmin = −3.8–0.0 °C, Topt = 28.0–34.6 °C, and Tmax = 35.2–37.2 °C. The growth of G. candidum J was slightly faster in milk with 1% NaCl and in temperature regions under 21 °C. However, in a temperature range that was close to the optimum, its growth was slightly inhibited by the lowered water activity level. The present study provides useful cultivation data for understanding the behaviour of G. candidum in milk and can serve as an effective tool for assessing the risk of fungal spoilage, predicting the shelf life of dairy products, or assessing the optimal conditions for its growth in relation to the operational parameters in dairy practices.

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