| 1. |
- Boysen, Marianne E., et al.
(författare)
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Effect of the biocontrol yeast Pichia anomala on interactions between Penicillium roqueforti, Penicillium carneum, and Penicillium paneum in moist grain under restricted air supply
- 2000
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Ingår i: Postharvest biology and technology. - : Elsevier. - 0925-5214 .- 1873-2356. ; 19:2, s. 173-179
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Tidskriftsartikel (refereegranskat)abstract
- Penicillium roqueforti was recently reclassified into the three species P. roqueforti, Penicillium carneum, and Penicillium paneum based on differences in ribosomal DNA sequences and secondary metabolites, e.g. mycotoxins. This is the first report on interaction between these closely related mould species under stress conditions. The yeast Pichia anomala (J121) inhibits growth of P. roqueforti in grain stored in malfunctioning airtight storage systems. The ability of P. anomala to inhibit all three species of the P. roqueforti group was examined in separate experiments as well as the competition between the three mould species when co-cultured with or without the yeast in non-sterile wheat grain (a(w) 0.95) under restricted air supply. Mould growth was analysed by dilution plating after 14 days and the individual colonies identified by random amplified polymorphic DNA (RAPD) fingerprinting. When co-culturing the P. roqueforti group in wheat without P. anomala all three species were able to grow to the same extent. Also, when co-culturing all species of the P. roqueforti group together with P. anomala, the growth response of the three species was very similar. Al yeast levels of 10(4) CFU g(-1),grain a pronounced inhibition was observed and at 10(5) CFU g(-1) grain a fungicidal effect was detected, indicating a potentiated effect of P. anomala when co-culturing the three mould species.
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| 2. |
- Petersson, Stina, et al.
(författare)
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Growth of Penicillium roqueforti, P-carneum, and P-paneum during malfunctioning airtight storage of high-moisture grain cultivars
- 1999
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Ingår i: Postharvest biology and technology. - : Elsevier. - 0925-5214 .- 1873-2356. ; 17:1, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- Penicillium roqueforti is an important spoilage fungus in high-moisture grain stored under airtight conditions where a malfunctioning storage system allows air leakage. It has recently been proposed that P. roqueforti be divided into three different species: P. roqueforti, P. carneum, and P. paneum (Boysen, M., Skouboe, P., Frisvad, J., Rossen, L., 1996. Reclassification of the Penicillium roqueforti group into three species on the basis of molecular genetic and biochemical profiles. Microbiology 142, 541-549). Differences in susceptibility to infection with the three mold species among winter wheat, spring wheat, rye, and barley during airtight storage of high-moisture grain were evaluated using a variety of grain cultivars. To simulate air leakage into such a storage system, grain (0.96 water activity) was inoculated, packed in glass tubes with a restricted air supply and incubated at 25 degrees C for 14 days. Molds and yeasts were quantified as colony forming units (CFU) on selective media. Generally, there was no difference in infection ability between P. roqueforti, P. carneum and P. paneum. All of them reached about 10(6) CFU/g in barley and winter wheat. However, rye appeared to be resistant to infection. A comparison of different barley and spring wheat cultivars revealed that P. roqueforti, P. carneum and P. paneum grew less vigorously on the malt cultivars Maud and Mentor and the spring wheat cv. Dragon than on other cultivars. In addition, batch-related differences in resistance to mold growth were found for spring wheat cv. Dragon.
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| 3. |
- Petersson, Stina, et al.
(författare)
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Pichia anomala as a biocontrol agent during storage of high-moisture feed grain under airtight conditions
- 1999
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Ingår i: Postharvest biology and technology. - : Elsevier. - 0925-5214 .- 1873-2356. ; 15:2, s. 175-184
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Tidskriftsartikel (refereegranskat)abstract
- Pichia anomala is antagonistic against a range of spoilage molds in vitro as well as against Penicillium roqueforti in high-moisture wheat during malfunctioning airtight storage in laboratory experiments. The use of Pichia anomala to improve the postharvest control of Penicillium roqueforti during airtight storage of feed grain was evaluated in outdoor silos. Inoculated and control winter wheat (cultivar Kosack) in 160-kg portions were stored at a water activity of 0.93 for 12 months in silos that were opened twice a week. During the first 2 months, inoculated Pichia anomala increased to about 10(7) colony-forming units (CFU)/g, while naturally occurring Pichia anomala in the treatments without inoculated yeast increased from 10(4) to 10(6) CFU/g. During the same period, CO2 concentrations increased to almost 70% and stabilized at 50-60%. During the coldest period, O-2 concentrations of <1% could be detected between samplings, whereas during the rest of the storage detectable O-2 levels were only found immediately after sampling. There were no clear differences in CO2 or O-2 levels between treatments. The inoculated Penicillium roqueforti did not grow during the storage period, probably owing to high numbers of Pichia anomala in combination with the high CO2 and low O-2 concentrations in the silos. In laboratory experiments, it was found that Pichia anomala survived long-term storage in airtight sealed test tubes better at 15 degrees C than at - 20 degrees C. The aerobic stability of moist wheat after 10 and 12 months of silo storage was clearly enhanced by an initial inoculation with Pichia anomala.
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| 4. |
- Venditti, Tullio, et al.
(författare)
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Repeated treatments with acetic acid vapors during storage preserve table grapes fruit quality
- 2017
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Ingår i: Postharvest biology and technology. - : Elsevier. - 0925-5214 .- 1873-2356. ; 125, s. 91-98
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Tidskriftsartikel (refereegranskat)abstract
- Postharvest losses on table grapes caused by Botrytis cinerea, are controlled with SO2 fumigations carried out every 7 or 10 d. The use of this gas is becoming more difficult to justify because of undesirable effects on the fruit and the increasing concern for human health. Objectives of the paper were to evaluate if repeated treatments with acetic acid (AC) during storage, were effective in preserving table grapes quality, comparing in addition the effects of AC and SO2 treatments. Experiments carried out in vitro on B. cinerea proved that the effect of AC on mycelia growth and conidia germination was related not only to the dose and exposure period, but also to the elapsed time between fungal inoculation and treatment. The reinoculum test demonstrated that a treatment with 20 μL L−1 of AC for 15 min had a fungicidal effect. A laboratory test was performed, to evaluate in vivo the effectiveness of AC on B. cinerea. Results suggested that higher doses were needed to control the pathogen. On naturally infected table grapes two storage experiments were carried out: in the first trial a single AC concentration of 50 μL L−1 was used to perform one or two fumigations after 4 or 8 weeks (w), while three different AC concentrations (30, 50 and 75 μL L−1) were used in the second trial and fumigations were repeated 5, 3 and 2 times respectively. Treatments lasted 15 min and fruit was stored for 8 w at 5 °C and 90% RH, followed by 3 d of a simulated marketing period. All treatments reduced gray mold incidence, with respect to untreated fruit, after 8 w of storage, but repeated treatments resulted the most effective. Two fumigations at 50 μL L−1 or 5 fumigations at 30 μL L−1 reduced gray mold incidence by 63.6 or 57.1% respectively.Fruit weight loss was significantly reduced by all treatments, while quality parameters resulted not to be affected by any of the treatments.
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| 5. |
- Ahmadi Afzadi, Masoud, et al.
(författare)
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Biochemical contents of apple peel and flesh affect level of partial resistance to blue mold
- 2015
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Ingår i: Postharvest Biology and Technology. - : Elsevier BV. - 0925-5214. ; 110, s. 173-182
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Tidskriftsartikel (refereegranskat)abstract
- Apple fruit contains a wide range of chemical compounds that may contribute to resistance against blue mold caused by Penicillium expansum. In the present study, contents of total titratable acidity, malic acid, total phenols and 10 individual phenolic compounds were quantified in peel and flesh fractions of both control and blue mold-inoculated fruits of 24 apple cultivars. In addition to the significant variation among cultivars in terms of all quantified compounds, correlation analysis revealed a significant impact of total phenols and individual phenols like flavonols and procyanidins B2 in the peel fraction, on blue mold resistance in the inoculated fruits. Multivariate analyses on data for chemical compounds in peel tissue of inoculated fruits, could also separate resistant and susceptible cultivars. These findings can be useful in breeding programs since higher levels of phenolic compounds may indicate better resistance in apple cultivars. (C) 2015 Elsevier B.V. All rights reserved.
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| 6. |
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| 7. |
- Mendoza, Fernando, et al.
(författare)
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Calibrated color measurements of agricultural foods using image analysis
- 2006
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Ingår i: Postharvest Biology and Technology. - : Elsevier BV. - 0925-5214. ; 41:3, s. 285-295
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Tidskriftsartikel (refereegranskat)abstract
- A computer vision system (CVS) was implemented to quantify standard color of fruit and vegetables in sRGB, HSV and L*a*b* color spaces, and image capture conditions affecting the results were evaluated. These three color spaces are compared in terms of their suitability for color quantification in curved surfaces. The results show that sRGB standard (linear signals) was efficient to define the mapping between R'G'B' (no-linear signals) from the CCD camera and a device-independent system such as CIE XYZ. The CVS showed to be robust to changes in sample orientation, resolution, and zoom. However, the measured average color was shown to be significantly affected by the properties of the background and by the surface curvature and gloss. Thus all average color results should be interpreted with caution. L*a*b* system is suggested as the best color space for quantification in foods with curved surfaces. (C) 2006 Elsevier B.V. All rights reserved.
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| 8. |
- Piombo, Edoardo
(författare)
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Fruit microbiome: A powerful tool to study the epidemiology of dry lenticel rot and white haze – Emerging postharvest diseases of apple
- 2023
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Ingår i: Postharvest Biology and Technology. - : Elsevier BV. - 0925-5214. ; 196
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Tidskriftsartikel (refereegranskat)abstract
- With the introduction of new apple varieties, emerging diseases have been recorded including dry lenticel rot and white haze. Ramularia mali has been identified as the causal agent of dry lenticel rot, whereas species of Golubevia, Tilletiopsis and Entyloma have been associated to white haze, but the epidemiology of these pathogens remains unclear. In the present study, we measured fruit disease incidence and quality parameters, and we used metabarcoding to characterize both epiphytic and endophytic microbial communities of apple fruit of two commercial cultivars, ‘Opal’ and ‘Ambrosia’, across six time points from early fruit development up to the end of shelf life. R. mali first develops in both cultivars as an endophyte at BBCH (Biologische Bundesanstalt, Bundessortenamt and CHemical industry) phenological phase 73 (10–11% relative abundance), BBCH 77 (26–33% relative abundance) and BBCH 81 (1–7% relative abundance), then it appears as an epiphyte from BBCH 87 onward (1–2% relative abundance), when symptoms start to be visible. This was confirmed in endophytic samples through qPCR specific for R. mali. Among the genera associated to white haze, Golubevia was the most abundant epiphyte (2–4%) from BBCH 81 to the end of shelf life. Alpha and beta diversity analyses unveiled the presence of significant difference both in richness and composition among different tissue, time points and cultivars. In conclusion, the study helps to explain the epidemiology of white haze and dry lenticel rot, and to design a targeted crop protection strategy, reinforcing the hypothesis that fruit metabarcoding could be a valuable tool for assessment and prediction of postharvest diseases, before symptoms occurrence in fruit.
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| 9. |
- Rocculi, Pietro, et al.
(författare)
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Effects of the application of anti-browning substances on the metabolic activity and sugar composition of fresh-cut potatoes
- 2007
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Ingår i: Postharvest Biology and Technology. - : Elsevier BV. - 0925-5214. ; 43:1, s. 151-157
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Tidskriftsartikel (refereegranskat)abstract
- We investigated possible physiological effects of the application of anti-browning substances on metabolically active potato tissues. The use of citric acid, ascorbic acid and L-cysteine for browning prevention of fresh-cut potatoes increased their metabolic heat production as measured by isothermal calorimetry. This effect was particularly high after treatment with L-cysteine, which also proved to be the most effective substance for inhibiting enzymatic browning. This increase in metabolic activity was concentration dependent and correlated with a decrease in the concentration of reducing sugars in the tissue, showing evidence that substances used in the prevention of enzymatic browning may have physiological effects in the tissue. The possible implications of these effects for the fresh-cut industry are discussed.
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| 10. |
- Sjöstrand, Joakim, et al.
(författare)
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Multiple factors affecting occurrence of soft scald and fungal decay in apple during storage
- 2023
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Ingår i: Postharvest Biology and Technology. - 0925-5214. ; 201
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Tidskriftsartikel (refereegranskat)abstract
- Some apple cultivars are highly susceptible to soft scald, a physiological disorder that can lead to large losses. The effect of harvest time, gradual cooling regimes and storage conditions on soft scald and fungal decay was investigated in two common apple cultivars, 'Aroma' and 'Frida' in a three year trial 2018-2020. Further, possible relationships between weather conditions during the growing season and 28 d before harvest and soft scald incidence along with fungal decay after storage were studied. The year with the highest rainfall had the highest incidence of soft scald and fungal decay. Our results suggest that the relative humidity during a period of 28 d before harvest was important for later development of soft scald in 'Frida', and together the results from 'Frida' and 'Aroma' showed a moderate correlation between relative humidity and soft scald. Gradual cooling showed conflicting results, and no treatment consistently lowered soft scald incidence. Gradual cooling led to inconclusive results, and storage in ambient air led to higher incidence of soft scald as compared to some investigated ULO storage conditions. Advanced maturity was associated with soft scald development and more fungal decay in one out of three years in 'Aroma', but did not affect incidence in 'Frida'. The etiology of soft scald seems to be dependent of multiple factors.
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