Postharvest Agents Research Articles

Chitosan-Bidens pilosa Extract-Based Coating with Enhanced Free Radical Scavenging, Antifungal, and Water Barrier Properties: Metabolite Profiling, Film Characterization, and Raspberry Preservation

Chitosan (Ch) was functionalized with Bidens pilosa (BP) extract at 1, 3, or 5% to form Ch-1 BP, Ch-3 BP, and Ch-5 BP, respectively. Ch without plant extract was used as a control. The composite films were characterized and tested for antifungal properties in the agar disc diffusion approach and antioxidant capacity in the 2,2-diphenyl-1-picrylhydrazyl assay. Chitosan films fused with B. pilosa extract inhibited the growth of P. expansum with a 10 mm inhibition diameter compared to control films (3.33 mm). Ch-1 BP exhibited the highest (79.13%) radical scavenging activity (RSA), and control films had the lowest RSA (50.97%). Liquid chromatography-mass spectrometry analysis identified 20 metabolites, including phenolic acids (9), organic acids (8), monosaccharides (1), amino acids (1), flavonoids (1), and six unknown polyphenols. Chitosan-based composite coating (Ch-1% BP) exhibited the lowest weight loss percentage (16.74%) and decay incidence (17.3%), while the untreated fruit showed higher weight loss and decay incidence (48.33% and 83.2%, respectively). The effectiveness of chitosan-enriched coating in maintaining the postharvest quality of raspberry fruit suggests that this plant could be a postharvest agent for controlling microbial spoilage and protecting against oxidative stress, ultimately resulting in extended storage in horticultural crops.

Extended Post-Harvest Effect of Melatonin in Fresh-Cut Broccolini Plants (Bimi®)

Melatonin has been shown to be effective as a post-harvest agent in fruits and vegetables. Melatonin has been used in the preservation of Brassicaceae such as broccoli, but not in broccolini. Here, fresh-cut broccolini (baby broccoli or BIMI®) were treated with different concentrations of melatonin (50 and 100 µM) for 15 or 30 min and cold stored for 28 days. Melatonin-treated broccolini had a longer shelf life than control samples, as seen by fresh weight (weight loss rate), hue angle (expresses color quality), and chlorophyll and carotenoid concentrations. Treatments with 50 µM melatonin for 15 min appear to be the most effective, reducing water loss by around 28% compared to the control and increasing the shelf life of fresh-cut broccolini, presenting an optimal conservation time of 7 days, and this could even be extended up to 14 days with acceptable quality. In addition, antioxidant, phenolic, and flavonoid contents were improved in melatonin-treated broccolini plants. Lipid peroxidation damage by cold storage was decreased in melatonin-treated broccolini, with a relevant decrease in malondialdehyde contents, especially 50 µM, on all days of storage. This study demonstrates for the first time the effectiveness of melatonin treatments in extending the shelf life of broccolini during cold storage. The possible commercial use of these treatments will be subject to the processes in the product management and marketing chain. However, more specific research about changes in organoleptic properties is necessary.

Effect of Melatonin in Broccoli Postharvest and Possible Melatonin Ingestion Level.

The post-harvest stage of broccoli production requires cold storage to obtain enough days of shelf life. It has been proved that melatonin is useful as a post-harvest agent in fruits and vegetables, including broccoli. In this study, the broccoli heads treated with melatonin have a longer shelf life than the control samples, which was reflected in parameters such as fresh weight, hue angle (expresses color quality), and chlorophyll and carotenoid contents. Treatments with 100 μM melatonin for 15 or 30 min seem to be the most appropriate, extending the broccoli’s shelf life to almost 42 days, when it is normally around 4 weeks. In addition, a study on the possible impact that melatonin treatments in broccoli could have on melatonin intake in humans is presented. The levels of superficial melatonin, called washing or residual melatonin, are measured, showing the possible incidence in estimated blood melatonin levels. Our results suggest that post-harvest treatments with melatonin do not have to be a handicap from a nutritional point of view, but more research is needed.

The efficacy of grapefruit seed extracts as postharvest agents

The efficacy of grapefruit seed extracts as postharvest agents

Grapefruit seed extracts as organic post-harvest agents: precious lessons on efficacy and compliance

Organic bananas for export are commonly protected against crown rot using formulations containing grapefruit seed extracts (GSEs). The production process and chemical composition of these GSEs are unclear; however, various formulations have been found to be compatible with organic agriculture standards as ‘plant preparations’ by organic certification bodies. In mid-2012, widespread contamination of bananas involving quaternary ammonium compounds (QACs), notably benzalkonium chloride (BAC) and didecyl dimethyl ammonium chloride (DDAC) was detected and could evidently be attributed to GSE formulations containing these compounds. The author reports the results of chemical analyses of commercial export consignments of organic bananas from Peru and Ecuador and pineapples from Costa Rica. These consignments were treated with approved commercial GSE-based organic post-harvest formulations. Analyses were conducted within the scope of a commercial residue screening programme. Results indicated frequent contamination of fruits with QACs. Chemical analysis of pure GSE-based post-harvest formulations showed widespread contamination with QACs, proving that these formulations cause QAC contamination in fruits. In vitro testing of the antimicrobial action of GSE-based formulations indicates that their efficacy is essentially due to QACs, which is confirmed in the previous literature. Because no credible chemical pathway for natural formation of QACs during extraction from grapefruit seeds has been found, QACs are considered as chemical contaminants. Certification bodies must be careful while evaluating the equivalence of such products to the standards of organic agriculture. Thorough information about the nature, origin, production process and chemical composition is needed in addition to scientific evidence of efficacy in the equivalence declaration process to avoid fraud.

In vitro Effects of Muscodor albus and Three Volatile Components on Growth of Selected Postharvest Microorganisms

Biofumigation by volatiles of Muscodor albus Worapong, Strobel & W.M. Hess, an endophytic fungus, was investigated for the biological control of three postharvest fungi, Botrytis cinerea Pers., Penicillium expansum Link, and Sclerotinia sclerotiorum (Lib) de Bary, and three bacteria, Erwinia carotovora pv. carotovora (Jones) Bergey et al., Pseudomonas fluorescens Migula (isolate A7B), and Escherichia coli (strain K12). Bacteria and fungi on artificial media in petri dishes were exposed to volatiles produced by M. albus mycelium growing on rye seeds in sealed glass 4-L jars with or without air circulation for up to 48 hours. The amount of dry M. albus–rye seed culture varied from 0.25 to 1.25 g·L–1 of jar volume. Fan circulation of volatiles in jars increased efficacy and 0.25 g·L–1 with fan circulation was sufficient to kill or suppress all fungi and bacteria after 24 and 48 hours, respectively. Two major volatiles of M. albus, isobutyric acid (IBA) and 2-methyl-1-butanol (MB), and one minor one, ethyl butyrate (EB), varied in their control of the same postharvest fungi and bacteria. Among the three fungi, IBA killed or suppressed S. sclerotiorum, B. cinerea, and P. expansum at 40, 25, and 45 μL·L –1, respectively. MB killed or suppressed S. sclerotiorum, B. cinerea, and P. expansum at 75, 100, and 100 μL·L –1, respectively. EB was only able to kill S. sclerotiorum at 100 μL·L –1. Among the three bacteria, IBA killed or suppressed E. coli (K12), E. carotovora pv. carotovora, and P. fluorescens at 5, 12.5, and 12.5 μL·L–1, respectively. MB killed or suppressed E. coli (K12), E. carotovora pv. carotovora, and P. fluorescens at 100, 75, and 100 μL·L–1, respectively. EB did not control growth of the three bacteria. This study demonstrates the need for air circulation in M. albus, MB, and IBA treatments to optimize the efficacy of these potential postharvest agents of disease control.

Caracterização físico-química de caquis cv. Fuyu submetidos à aplicação de agentes inibidores de escurecimento e armazenados a 0°C

Its goal was to evaluate the effects of postharvest agents to prevent browning in persimmon fruits (Diospyros kaki L.) cv. Fuyu. The fruits were immersed for two minutes into a solution containing ascorbic acid, citric acid and calcium chloride and adhesive spreader (vegetable oil) 0.02% (v/v), dried at room temperature and immediately stored at 0 ± 2ºC and 95±2% UR. The fruits were evaluated on the 32nd and 52nd days to check epidermal darkness, percentage of dark fruits, firmness, total soluble solids, pH of the pulp and total acidity. After 52 days no effects of the products were observed to prevent epidermal darkness from manifesting on the persimmon fruits. Fruit treated with citric acid remained firm and presented lower levels of total soluble solids up to the 52nd day. There was an increase in total acidity in light of the evaluation period, and small variation in the pH of the pulp.

Chlorpropham induces mitochondrial dysfunction in rat hepatocytes.

The metabolism and action of chlorpropham (isopropyl N-(3-chlorophenyl)carbamate; CIPC, a post-harvest agent) and its metabolites were studied in freshly isolated rat hepatocytes and isolated rat hepatic mitochondria, respectively. The exposure of hepatocytes to CIPC caused a concentration (0.25-1.0 mM)- and time (0-3h)-dependent cell death accompanied by loss of cellular ATP and adenine nucleotides. CIPC at a weakly toxic level (0.5 mM) was metabolized to isopropyl N-(3-chloro-4-hydroxyphenyl)carbamate (4OH-CIPC) and subsequently to its glucuronide and sulfate conjugates (major metabolites) or alternatively to a minor metabolite 3-chloroaniline (3CA). The addition of SKF-525A (50 microM), an inhibitor of microsomal monooxygenase, enhanced the CIPC (0.5 mM)-induced cytotoxicity accompanied by loss of ATP and 4OH-CIPC and inhibited the decrease in the concentration of the parent compound. CIPC led to a strong decrease in cellular ATP content compared to its metabolites, 4OH-CIPC and 3CA. On the other hand, the exposure of isolated hepatic mitochondria to CIPC reduced State 3 respiration with a FAD-linked substrate (succinate plus rotenone) and/or with a NAD+ -linked substrate (pyruvate plus malate), whereas State 3 respiration with ascorbate plus tetramethyl-p-phenylendiamine (cytochrome oxidase-linked respiration) was not affected markedly by CIPC. Further, the addition of CIPC caused an increase in the rate of State 4 oxygen consumption, indicating an uncoupling effect, and a decrease in the rate of State 3 oxygen consumption in a concentration-dependent manner, respectively. In contrast, the addition of neither 4OH-CIPC nor 3CA markedly affected the rate of states 3 and/or 4 oxygen consumption. These results indicate that CIPC-induced cytotoxicity is mediated by the parent compound rather than by its metabolites such as 4OH-CIPC and 3CA, and that the toxicity is associated with a rapid depletion of ATP via impairment of mitochondrial function related to oxidative phosphorylation.

Biotransformation of chlorpropham (CIPC) in isolated rat hepatocytes and xenoestrogenic activity of CIPC and its metabolites by in vitro assays

1. The metabolism and action of chlorpropham (isopropyl N-(3-chlorophenyl)carbamate; CIPC, a post-harvest agent) were studied in freshly isolated rat hepatocytes, and the oestrogen-like activity of CIPC and its metabolites was assessed by in vitro assays. The exposure of hepatocyte suspensions to CIPC caused concentration- (0.25–1.0 mM) and time- (0–3 h) dependent cell death, which was assessed by Trypan blue exclusion, accompanied by losses of cellular adenosine triphosphate and adenine nucleotide pools, and formation of cell bleb.2. CIPC at a weakly toxic level (0.25 or 0.5 mM) was metabolized to isopropyl N-(3-chloro-4-hydroxyphenyl)carbamate (4OH-CIPC) and subsequently to its glucuronide and sulfate conjugates (major metabolites) or alternatively to the minor metabolites 3-chloroaniline (3CA) and 3-chloroacetanilide. CIPC (0.25 mM) added to hepatocyte suspensions was distributed equally between hepatocytes and the extracellular medium during the incubation. The glucuronide rather than the sulfate conjugate of 4OH-CIPC predominantly increased in the medium with time, while the amount of unconjugated free 4OH-CIPC in the extracellular medium increased by approximately threefold compared with the amount in the cell fraction after 0.5 h and then decreased rapidly accompanied by increases in the conjugates. This indicates that unconjugated free 4OH-CIPC produced in hepatocytes was temporarily excreted in the extracellular medium and subsequently converted to the conjugates via re-influx into hepatocytes.3. Diethylstilbestrol (DES), bisphenol A (BPA) and 4-hydroxybenzoic acid butyl ester (butylparaben), which are known xenoestrogenic compounds, competitively displaced 17β-oestradiol bound to the oestrogen receptor-α (ERα) in a concentration-dependent manner; IC50 values of DES, BPA, butylparaben and its derivative 3-chloro-4-hydroxybenzoic acid butyl ester (3-chloro-butylparaben) were approximately 10−8, 10−5, 5 × 10−5 and 5 × 10−4 M, respectively. In contrast, neither CIPC nor 4OH-CIPC impaired the binding of 17β-oestradiol to ERα at concentrations ranging from 10−9 to 10−4 M, whereas at concentrations of >5 × 10−4 M, the binding affinity of 4OH-CIPC was greater than that of CIPC. In a proliferation assay of MCF-7 cells, CIPC, 4OH-CIPC and 3CA did not increase cell numbers at concentrations ranging from 10−9 to 10−5 M, but these compounds at a concentration of 10−4 M induced a considerable decrease in cell numbers relative to the control. The results suggest that even if CIPC is metabolized to 4OH-CIPC by hepatocytes, the chlorine adjacent to the 4-hydroxy group added to the intermediate as well as 3-chloro-butylparaben obstructs the appearance of oestrogen-like effects via an interaction between the intermediate and the ER.

Trichoderma viride Suppresses Fumonisin B1 Production by Fusarium moniliforme

Biocontrol activity against Fusarium moniliforme was analyzed for a Trichoderma viride strain isolated from root segments of corn plants grown in Piedmont Georgia. The isolate suppressed radial extension of F. moniliforme colonies during cocultivation on potato dextrose agar and fumonisin B1 (FB1) production during incubation of both fungi on corn kernels. T. viride decreased radial extension of F. moniliforme by 46% after 6 days and by 90% after 14 days. Furthermore, the colony diameter of F. moniliforme was less at 14 days than at 5 days, suggesting that F. moniliforme mycelia were undergoing lysis. FB1 production by F. moniliforme on corn kernels decreased by 85% when both organisms were inoculated the same day onto corn kernels and by 72% when inoculation of T. viride was delayed by 7 days after F. moniliforme inoculation. These results are the first to demonstrate that T. viride can suppress FB1 production by F. moniliforme, thereby functioning to control mycotoxin production. Thus, this isolate may be useful in biological control to inhibit F. moniliforme growth as a preharvest agent to prevent disease during plant development and/or as a postharvest agent during seed storage to suppress FB1 accumulation when kernels are dried inadequately.