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This study illustrates the effects of light quality as influenced by photo-selective shade nets (red, yellow, and pearl with 40% shade) and the widely used commercial black net (25% shade) on overall retail quality and phytochemical contents of three lettuce (Lactuca sativa L.) varieties (two green varieties, Ashbrook and Aquarell, and a red variety, Exbury) at after postharvest storage. Variety-specific responses were observed with respect to different coloured shade nets with regards to the accumulation of β-carotene, ascorbic acid, flavonoids (kaempferol, isorhamnetin, quercetin, myricetin, anthocyanin), and antioxidant activity at harvest. Growing var. Ashbrook under the pearl net improved the ascorbic acid and myricetin contents after postharvest storage. Var. Exbury (red) produced under the black net showed higher retention of ascorbic acid, and anthocyanin contents after postharvest storage. Also pearl net production improved the jS-carotene content after postharvest storage in var. Aquarell. All lettuce types produced under the pearl nets showed less weight loss, and overall acceptance after postharvest storage. Spectral quality under the shade nets enabled us to improve the phytochemical content and antioxidant properties in light-sensitive varieties Ashbrook Aquarell and Exbury, during winter season. [ABSTRACT FROM AUTHOR]

Brown rot ( Monilinia spp.) affects the shelf life, fruit quality and marketability of peaches ( Prunus persica L.). Increasing consumer concern regarding food safety makes it necessary to search for natural environmentally friendly alternative products for postharvest disease control. In this investigation, polyethylene terephthalate (PET) punnets containing thyme oil (TO sachets) and sealed with chitosan/boehmite nanocomposite lidding films significantly reduced the incidence and severity of brown rot caused by Monilinia laxa in artificially inoculated peach fruits (cv. Kakawa) held at 25 °C for 5 days. Furthermore, PET punnets containing TO sachets and sealed with chitosan/boehmite nanocomposite lidding films significantly reduced the brown rot incidence to 10% in naturally infected fruits stored at 0.5 °C, 90% RH for 7 days and at the simulated market shelf conditions for 3 days at 15 °C, 75% RH. The chitosan/boehmite nanocomposite lidding films maintained the active components of thyme oil, thymol (56.43% RA), caryophyllen (9.47% RA) and β -linalool (37.6% RA) within the (head space volatiles) punnet. Panellists preferred fruits packed from commercial punnet containing thyme oil (sachets) and sealed with chitosan/boehmite nanocomposite lidding films due to overall appearance, taste, and natural peach flavour. [ABSTRACT FROM AUTHOR]

Avocado fruit has high economic value; however, major post-harvest losses are encountered throughout the supply chain mostly due to anthracnose disease caused by the fungus Colletotrichum gloeosporioides. Increasing consumer concern regarding food safety and demand for organically produced fruits makes it necessary to search for natural environmentally friendly alternative products and processes for the fruit industry; particularly in disease control. Antifungal effects of Gum Arabic (GA) (10%), Aloe vera (AL) (2%), chitosan (CH) (1%) alone or in combination with thyme oil (1%) were investigated in vitro. CH + thyme oil and AL + thyme oil [1:1 or 3:1 v/v] showed fungicidal effects while AL, CH, GA and GA + thyme oil [3:1 v/v] showed fungistatic effects on mycelial growth of C. gloeosporioides in vitro. CH and AL coatings alone or in combination with thyme oil [3:1 v/v], either as preventative or curative treatments in comparison with commercial treatment (prochloraz, 0.05%) and untreated control were evaluated on incidence and severity (lesion diameter) of anthracnose in vivo. Preventative CH + thyme oil treatments significantly reduced the severity of anthracnose (8.9 mm) compared to thyme oil (12.7 mm), AL + TO (14.4 mm), CH (17.8 mm), AL (20.6 mm), PZ (18.3 mm) and untreated samples (34.8 mm). As curative method, the CH + thyme oil combination also reduced the severity of anthracnose by at least 4 mm compared to the other treatments. The total phenols, polyphenol oxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, chitinase, catalase and superoxide dismutase activities, firmness and flesh colour were also determined. Results showed an increase in peroxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, chitinase, catalase and superoxide dismutase activities and total phenolics with reduced loss of firmness and flesh colour following CH + thyme oil treatments. This investigation recommends CH + thyme oil [3:1 v/v] combination treatment as a suitable alternative to the currently adopted prochloraz applications in controlling anthracnose disease in avocado fruit during storage. [ABSTRACT FROM AUTHOR]

Postharvest diseases are one of the major causes for the postharvest loss of horticultural fresh produce during the supply chain. The incidence of postharvest diseases can affect the quality and restrict the shelf life of the horticultural fresh produce. At present strict regulations are enforced by the fresh produce importing countries regarding the minimum pesticide residue levels in the edible portion of the fresh produce. Some fungal pathogens were reported to develop resistance to synthetic fungicides. Waste disposal of fungicides has an impact on environmental footprint. All theses above-mentioned reasons have necessitated the search for a natural novel fungicide to replace the synthetic fungicide application in the packing line as postharvest treatment. Consumer preference to organic fresh produce is increasingly becoming popular in the developed countries. Therefore, this review summarises the use of essential oils in the control of postharvest diseases of horticultural commodities, their mode of actions, effects on the defence mechanism and quality of fresh fruit. Future research must be focused on conducting large scale trials to prove the feasibility of combination treatments. The cost benefit analysis of the treatments needs to be carried out in order to implement their application and the commercial applications of essential oils and host pathogen infection must be investigated in detail in order to control latent infections during postharvest storage. [ABSTRACT FROM AUTHOR]

Abstract: Due to their flavor and nutritional characteristics, papaya fruit are consumed worldwide. As a tropical commodity, storage has serious limitations that result in their rapid deterioration and high incidence of rots during handling and storage. Postharvest handling of papaya differs according to destination. For export markets, there are well-defined postharvest steps established that include technologies that generally avoid disease incidence. For national markets, the postharvest chain is short but characterized by poor handling practices that can result in serious losses due to microorganisms. Anthracnose is considered the main postharvest disease, but development of other rots may also limit good fruit quality, as is the case with, among others, stem-end rots. Control of papaya rots for export markets are applied in accordance with import–export regulations, while for the national market it has typically relied on synthetic fungicides; however, due to their already known ‘side-effects’ on humans and the environment, other alternatives alone or combined should be tested in integrated technologies. We reviewed the available literature on different control methods to reduce postharvest diseases during papaya storage, including those that reported on their effects on fruit quality. Wax combined with fungicides and heat is currently in use. Other methods, such as the application of irradiation, antagonistic microorganisms and natural compounds [e.g. chitosan and plant derivatives (extracts, essential oils and isothiocynates)], are still under evaluation, but have yielded promising initial results. The application of various organic salts and minerals and modified and controlled atmosphere technologies using ozone and volatiles such as 1-methycyclopropane are also under experimentation. We believe that research areas that include preharvest experimentation aimed at reducing postharvest diseases on papaya fruit should be taken into account. Finally, the integration of more than one control method will reduce the incidence of rots, and therefore improve and extend the storage life of this important commodity. [Copyright &y& Elsevier]

Abstract: Efficacy of biocontrol agent Bacillus amyloliquefaciens PPCB004 was evaluated on the control of anthracnose and phomopsis rot in ‘Solo’ papaya pre-treated with 1-methyl cyclopropene (100 μl) (1-MCP) during storage. This treatment was compared to the untreated control, commercial treatment (washing in chlorinated water), stand alone 1-MCP and PPCB004 treatment. Although fruit pre-treated with 1-MCP delayed the ripening (100% yellow) after cold storage by 9–10 d, it showed higher incidence and severity of anthracnose and phomopsis rot than the fruit subjected to commercial treatment. Application of PPCB004 after 1-MCP pre-treatment (1-MCP + PPCB004) reduced the anthracnose and phomopsis incidence and severity after cold storage (10 °C, 85% RH for 14 d) and ripening at 25 °C. The 1-MCP + PPCB004 treatment helped to retain the fruit firmness, overall quality and uniform yellow skin (100%) and flesh colour after ripening. The PPCB004 was effectively recovered from stand alone PPCB004 and 1-MCP + PPCB004 treated fruit after cold storage and ripening. The PPCB004 population showed an increase by 1 log units after ripening in 1-MCP + PPCB004 treated fruit. After ripening the recovery of PPCB004 population was higher (0.7 log units) in 1-MCP + PPCB004. The total recovery of fungal population on the fruit surface after ripening was lower in 1-MCP + PPCB004 and stand alone PPCB004 treated fruit. It can be concluded that application of B. amyloliquefaciens PPCB004 with 1-MCP pre-treated papaya (at 25–30% skin yellow stage) can significantly reduce disease incidence associated with 1-MCP treatment. This treatment has the potential for commercial application in the ‘organic’ papaya industry. [ABSTRACT FROM AUTHOR]

Abstract: Bacillus amyloliquefaciens PPCB004 was selected as a potential antagonist to control Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer on peach fruit. The HPLC data of PPCB004 indicated the lipopeptides iturin A, fengycin and surfactin as secondary metabolites. The GC/MS analysis of PPCB004 showed 3-hydroxy-2-butanone as the dominant compound (97.52% of relative peak area). Thyme (TO) and lemongrass (LO) oils showed over 50% and 25% inhibition of radial mycelial growth respectively with 8μl oil per plate for all pathogens. Combination treatment with both oils failed to increase the percentage inhibition of radial mycelial growth of the pathogens. Combined application of PPCB004 with TO or LO was tested to assess the effectiveness in the control of these pathogens during postharvest storage. The biofilm formation of PPCB004 was significantly higher in LO than TO. LO (6μlplate−1) and PPCB004 completely inhibited the mycelial growth of the pathogens. Fruit inoculation trials with PPCB004+LO in NatureFlex™ modified atmosphere packaging (MAP), showed lower disease incidence and severity at 25°C for 5d than treatments with PPCB004+MAP, PPCB004+TO+MAP, LO+MAP, TO+MAP or stand-alone MAP. On naturally infected fruit, PPCB004+LO+MAP and LO+MAP treatments retained the total soluble solids/titratable acidity ratio and flesh firmness but failed to stimulate the levels of total phenolic content, phenylalanine ammonia-lyase, β-1,3-glucanase and chitinase activities. Combination of PPCB004 (spray treatment)+LO (in pad delivery system) in NatureFlex™ MAP showed absence of disease and off-flavour development, retained the overall appearance and increased the overall acceptance at market shelf conditions (20°C for 2d) after cold storage at 4°C for 14d. [Copyright &y& Elsevier]

Abstract: The effects of modified atmosphere packaging (MAP) [bioriented polypropylene (BOPP-1 or BOPP-2)] in combination with antimicrobial agents Bacillus subtilis, 107 colony-forming units (cfu)ml−1; ethylenediamine tetraacetic acid, calcium disodium salt hydrate (EDTA) (0.1%); or 4-hexylresorcinol (4-HR) (0.15%) on postharvest decay control and quality retention of litchi cv. McLean''s Red were assessed as possible replacements for commercial SO2 fumigation. Fruits dipped in B. subtilis, EDTA or 4-HR (5min) separately, blow dried (25°C, 3min), packed in BOPP-1, held for 18d at 2°C, 95% RH, and 2d at 14°C, 75% RH were significantly less decayed. The antagonist–BOPP-1 combination also promoted the best bacterial survival during storage. B. subtilis was observed to survive effectively in BOPP-1 (16% O2, 6% CO2; ∼90% RH), but its survival was adversely affected in BOPP-2 (5% O2, 8% CO2; ∼93% RH). Alternaria alternata and Cladosporium spp. were the major decay-causing fungi in BOPP-1 treatments, and Candida, Cryptococcus and Zygosaccharomyces were the predominant yeasts in BOPP-2 treatments. Combination treatments EDTA, 4-HR or B. subtilis in BOPP-1 inhibited polyphenol oxidase (PPO) and significantly reduced pericarp browning and severity. Although the combination treatments EDTA, 4-HR or B. subtilis in BOPP were equally effective in controlling decay and browning, the EDTA and 4-HR affected the natural pinkish-red colour of the pericarp by showing higher h° values (orange–pink). Among the combination treatments, B. subtilis+BOPP-1 had the best potential to control decay, retain the colour and the overall litchi fruit quality during a marketing chain of 20d. [Copyright &y& Elsevier]

The efficacy of modified atmosphere packaging (MAP), Xtend® (XF) or biorientated polypropylene (BOPP), and hot water dip treatments on quality retention in the litchi cultivar ‘McLean's Red’ was evaluated as an alternative to SO2-fumigation. Fruits were dipped in hot water at different temperatures and time regimes [50°C × 2 min; 55°C × 1 min; or 60°C × 1 s] and packed in XF or in BOPP. The XF bags were closed with rubber bands, while the BOPP bags were heat-sealed to modify the atmosphere around the fruit. Packed fruits were placed in commercial cardboard cartons and stored at 2°C and 95% RH for 34 d to simulate commercial export conditions. Commercial SO2-fumigation, and fruit without any hot water dip treatment packed in XF or BOPP were included as controls. Weight loss, firmness, pericarp browning, severity of decay, Hunter colour values, titratable acidity, fruit pH and soluble solids concentrations were determined after storage. Sensory analysis was carried out to determine colour retention of the pericarp and aril, flavour qualities, taste, odour, juiciness and overall consumer acceptability. Fruit packed in BOPP showed reduced weight loss, colour deterioration and decay, and retained excellent eating quality during long-term storage due to the high RH and higher O2 concentrations (17%) around the fruit. Hot water dip treatments at 50°C for 2 min, or at 55°C for 1 min, caused deleterious effects on pericarp colour, surface structure and quality parameters. [ABSTRACT FROM AUTHOR]

Freshly-harvested litchi (Litchi chinensis Sonn., L) fruit, of the cultivar `Mauritius', were subjected to 5 mm post-harvest dip treatments in aqueous solutions of: potassium metabisulphite, or Vapogard®, or Chitosan or combined treatments of: potassium metabisulphite + Vapogard®, or Chitosan + potassium metabisulphite, or Anolyte® + Triton X-100 + Chitosan, or ammonia + Carnauba wax. Standard commercial sulphur dioxide fumigation was included as a comparative control. After treatment, fruit were held at 1°C, 95% RH for 21 d to simulate refrigerated sea shipment conditions, then held at 18°C, 80% RH for 2 d. Several parameters were used to evaluate fruit quality. Combined post- harvest dip treatment with potassium metabisulphite + Vapogard® retained fruit marketability most effectively, preventing severe browning post-harvest diseases, and retaining fruit firmness. Potassium metabisulphite + Vapogard® dip treatment also revealed superior eating quality, with a 19.5% soluble solids concentration, 0.2% titratable acidity and a decline in anthocyanin concentration. Fruit fumigated with sulphur dioxide showed increased weight loss with intensified micro-cracks on the pericarp. Chitosan was most effective in reducing the total microbial fructoplane population compared to other treatments. Penicillium expansum Link. and Cladosporium spp. were identified as the predominant fungi on litchi fruit used in this trial. [ABSTRACT FROM AUTHOR]

The phenolic content and antioxidant properties of fruits would be underestimated if the extraction method is not optimised and bound phenolic content are not considered. A Central Composite Design and Response Surface Methodology were used to optimize sonication time and ethanol concentration to obtain a food-grade phenolic extract from Natal plum fruit (Carissa Macrocarpa). The free and bound phenolics of Natal plum fruit were extracted, and their release was simulated by in vitro digestion. Optimal conditions (38% ethanol and 16.7 min of ultrasonication) yielded 863.99 mg kg-1 fresh weight of total phenolics and 421.52 mg kg-1 fresh weight of total anthocyanins. There were strong correlations between ferric reducing capacity to cyanidin 3-sambubioside (Cy-3-Sa) (R2 = 0.948), and cyanidin 3-O-glucoside (Cy-3-G) (R2 = 0.901). Compared to alkaline hydrolysis, acid hydrolysis produced more bound phenolic compounds. The optimum extract still had low anthocyanin bioaccessibility. The optimal extract of the Natal plum fruit may serve as a functional ingredient due to its high antioxidant capacity. • The Natal plum fruit (NP) (Carissa Macrocarpa) is native to Southern Africa. • Ultrasonication with 38% ethanol for 16.7 min yielded higher total phenols. • The acid hydrolysis of NP released more bound phenolic compounds. • Anthocyanins are mostly degraded by protocatechuic acid in the intestine. [ABSTRACT FROM AUTHOR]

The OPLS-DA, the UPLC–QTOF/MS and chemometric approaches were adopted to discriminate the different varieties belonging to three pumpkin species. Furthermore, this study included a comparison of the phenolic metabolites, antioxidant (DPPH, FRAP and ABTS activity), in vitro α-glucosidase and α-amylase activities, and cell cytotoxicity of the leaves of three varieties of pumpkin species (Cucurbita moschata, C. maxima, and C. pepo). Leaves of all three varieties of pumpkin species contained 23 phenolic metabolites. The OPLS-DA, the UPLC–QTOF/MS and chemometric approach showed that genistin was the candidate biomarker responsible for the separation of butternut squash (C. maxima) from the other two species, while 7-methylquercetin-3-galactoside-6″-rhamnoside-3‴-rhamnoside separated the Caserta squash (C. pepo) from the other two pumpkin species. Leaves of Green Hubbard (C. maxima) showed the highest antioxidant capacity (FRAP and ABTS activities), while butternut squash (C. moschata) showed the highest DPPH scavenging activity. Leaf extracts of butternut squash (C. moschata) and Green Hubbard (C. maxima) showed higher inhibition of α-glucosidase activity (IC 50 18.22 μg mL−1) and α-amylase (IC 50 18.11 μg mL−1) activities respectively, with no cytotoxic effect detected. The phenolic metabolites identified herein for the leaves of each variety of pumpkin species can be potential control markers for further standardisation. Leaves of Green Hubbard (C. maxima) provides functional properties for health benefits. • Genistin detected in the leaves separated the C. maxima from the other two pumpkin species. • 7-methylquercetin-3-galactoside-6″-rhamnoside-3‴-rhamnoside separated the C. pepo from the other pumpkin species. • Leaves of Green Hubbard (C. maxima) showed the highest antioxidant capacities. • Green Hubbard (C. maxima) showed higher inhibition of α-glucosidase and α-amylase activities. • No cytotoxic effect detected in the leaves of all three pumpkin varieties. [ABSTRACT FROM AUTHOR]

The objective of this investigation was to evaluate household cooking techniques on the changes of colour properties, antioxidants and antioxidant activity (FRAP activity), as well as the sensory quality of African pumpkin and pumpkin leaves. Steaming reduced the colour difference (ΔE) in the leaves of African pumpkin and pumpkin compared to stir-frying, boiling or microwaving. Steaming led to a reduced loss of total chlorophyll content but increased the total carotenoid content by 22.65% in leaves of African pumpkin compared to the other three methods. Steaming reduced the loss of total phenolic content and retained the antioxidant activity in both African pumpkin and pumpkin leaves compared to the other methods, whilst stir-frying and steaming reduced the loss of total flavonoids in the leaves of African pumpkin and pumpkin, respectively. The sensory evaluation indicated that the stir-fried leaves of African pumpkin and pumpkins are preferred, whilst the steamed leaves are preferred secondly, compared to the boiled or microwaved leaves, which are least tasty. • Steaming reduced the loss of total chlorophyll content in African pumpkin leaves. • Steaming increased the total carotenoids in African pumpkin leaves than raw leaves. • Steaming reduced the loss of antioxidant activity in the leaves of African pumpkin and pumpkin. • Boiling and microwaving caused greater loss of the antioxidants and the antioxidant activity. • Steaming is the suitable cooking technique for African pumpkin and pumpkin leaves. [ABSTRACT FROM AUTHOR]

Natal plum is a South African indigenous fruit. Natal plum were stored at 2, 4, 10 and 25 °C (control) temperatures up to 12 days, and fruit were evaluated at 4 day intervals for changes in quality and phenolic compounds. The results showed that 2 °C significantly reduced the weight loss and total colour difference while maintaining the quality attributes. Supervised Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) and the ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometer and chemometric approach separated the fruit stored at low temperature from those stored at 25 °C, and a unique marker compound quinic acid was identified with the low temperature fruit. Similarly, cyanidin (aglycone) separated the fruit stored at 2 °C from those stored at other lower temperatures (4, and 10 °C). Thus, it can be proposed that the temperature stress at 2 °C had favoured the cold-induced accumulation of cyanidin derivatives (anthocyanins) to provide chilling tolerance. The bioactive compounds (cyanidin-3- O -pyranoside (10.4 mg kg−1), cyanidin-3- O -glucoside (54 mg kg−1), and quercetin 3- O -rhamnosyl glucoside (57 mg kg−1)] and the antioxidant activity (FRAP assay) were significantly higher in fruit stored at 2 °C for 12 days. Thus, storage of Natal plum at 2 °C for 12 days can be recommended if the fruit are used as a functional ingredient. [ABSTRACT FROM AUTHOR]