Cultivar and Postharvest Storage Duration Influence Fruit Quality, Nutritional and Phytochemical Profiles of Soilless-Grown Cantaloupe and Honeydew Melons.

There is an increasing demand for sweet melon (Cucumis melo L.) fruit in fruit and vegetable markets due to its nutritional content, resulting in different cultivars being grown in different production systems. This study evaluated the nutritional and phytochemical contents of soilless-grown cantaloupe and honeydew sweet melon cultivars at harvest and postharvest. At harvest, vitamin C and ß-carotene concentrations were higher in orange-fleshed (cantaloupe) cvs. Magritte, Divine, Majestic, Cyclone, MAB 79001, E25F.00185, E25F.00075 and Adore, compared to green-fleshed (honeydew) cvs. Honey Brew and Honey Star. The zinc (Zn), phosphorus (P), potassium (K), magnesium (Mg) and calcium (Ca) contents were higher in orange-fleshed compared to green-fleshed cultivars. Total phenolics content (TPC) in cv. E25F.00075 was the highest (2.87 mg GAE∙g-1 dry weight). A significant, positive, correlation occurred between ß-carotene and Zn, P, K, Ca and Mg contents. Postharvest storage duration affected TPC and total soluble solid content. The interaction of cultivar and postharvest storage duration affected flavonoid, vitamin C and ß-carotene contents, free radical scavenging activity and fruit juice pH. Vitamin C and ß-carotene contents decreased with increased postharvest storage duration while flavonoid content increased. The cantaloupe cultivars performed significantly better compared to the honeydew cultivars as evident in their high mineral element content, and vitamin C and ß-carotene concentrations. Selection of appropriate cultivars in a production system should consider variation in nutritional traits of cultivars and postharvest storage duration. Soilless production of sweet melon cultivars in tunnels offers a viable alternative to open field to produce high-quality melons at harvest and postharvest.

Biomass, Essential Oil Yield, and Composition of Marjoram as Influenced by Interactions of Different Agronomic Practices under Controlled Conditions.

Origanum marjorana L. has been valued for centuries for its flavoring attributes and therapeutic properties. The growing demand for its various applications necessitates optimizing agronomic practices for its production. A glasshouse pot trial was conducted to identify optimum agronomic practices for increased herbage and oil yield, as well as oil quality. The effects of varying air temperature regimes (low, medium, and high levels), irrigation (low, medium, and high levels), nitrogen fertilizer application (N = 100, 150, and 200 kg/ha), and soil type (sandy loam, sandy clay loam, and loamy sand) on the productivity of marjoram plants were investigated. The results showed an increase in plant growth and herbage yield as well as chlorophyll content under conditions of high air temperature, low irrigation, and moderate to high nitrogen level applied to sandy loam soil, with an increase in oil yield with loamy sand soil. The major compounds observed in marjoram essential oil were terpinene-4-ol (22.63-36.72%) and (Z)-ß-terpineol (6.85-16.60%), in which terpinene-4-ol was not found to be within the International Organization for Standardization (ISO) limits of acceptability while (Z)-ß- terpineol had no reference limits available. A promising performance of marjoram cultivation under high regimes of air temperature (16.7 to 36.6 °C), nitrogen fertilization (200 kg ha-1 N), and low irrigation (up to 60% soil water depletion from field capacity) on sandy loam soils was demonstrated for improved crop productivity.

Different Postharvest Responses of Fresh-Cut Sweet Peppers Related to Quality and Antioxidant and Phenylalanine Ammonia Lyase Activities during Exposure to Light-Emitting Diode Treatments.

The influence of emitting diode (LED) treatments for 8 h per day on functional quality of three types of fresh-cut sweet peppers (yellow, red, and green) were investigated after 3, 7, 11, and 14 days postharvest storage on the market shelf at 7 °C. Red LED light (660 nm, 150 µmol m-2 s-1) reduced weight loss to commercially acceptable level levels (≤2.0%) in fresh-cuts of yellow and green sweet peppers at 7 and 11 d, respectively. Blue LED light (450 nm, 100 µmol m-2 s-1) maintained weight loss acceptable for marketing in red fresh-cut sweet peppers up to 11 d. Highest marketability with minimum changes in color difference (∆E) and functional compounds (total phenols, ascorbic acid content, and antioxidant activity) were obtained in yellow and green sweet pepper fresh-cuts exposed to red LED light up to 7 and 11 d, respectively, and for red sweet pepper fresh-cuts exposed to blue LED light for 11 d. Red LED light maintained the highest concentrations of ß carotene, chlorophyll, and lycopene in yellow, green, and red sweet pepper fresh-cuts up to 7 d. Similarly, blue LED light showed the highest increase in lycopene concentrations for red sweet pepper fresh-cuts up to 7 d. Red LED (yellow and green sweet peppers) and blue LED (red sweet pepper) lights maintained phenolic compounds by increasing phenylalanine ammonia lyase activity. Thus, the results indicate a new approach to improve functional compounds of different types of fresh-cut sweet pepper.

Cultivar-specific responses in red sweet peppers grown under shade nets and controlled-temperature plastic tunnel environment on antioxidant constituents at harvest.

Antioxidant constituents such as carotenoids (capsanthin, phytoene, lutein, ß-cryptoxanthin), polyphenols content (p-coumaric, ferulic, p-hydroxybenzoic, caffeic acid, sinapic acid, and quercetin-3-glucoside) and marketable yield were investigated in 11 sweet pepper cultivars grown under controlled temperature plastic tunnel and white shade net. Marketable yield was not affected by either of the environments, while the interaction between cultivar and growing environment significantly affected the accumulation of antioxidant constituents. The principal component analysis illustrated that controlled temperature plastic tunnel improved the accumulation of carotenoid components and ascorbic acid and vitamin C content in most cultivars. On the contrary, white shade nets favoured the accumulation of phenolic compounds and ORAC activity in most cultivars. A strong correlation was noted between phytoene and carotenoid components in this study (capsanthin r = 0.60; P < 0.001; lutein r = 0.75; P < 0.001; ß-carotene r = 0.78; P < 0.001) while ORAC correlated with phenolic compounds. Based on this study, it is possible to refine the choice of environment and cultivar to enhance individual antioxidant constituent groups to improve health benefits for consumers.

Impact of transportation, storage, and retail shelf conditions on lettuce quality and phytonutrients losses in the supply chain.

This study was initiated to investigate the impact of transportation, storage, and retail shelf conditions on lettuce quality and phytonutrients losses in the urban fresh produce market supply chain. Reducing postharvest losses is a priority to reduce the loss of the dietary-based phytonutrients and to improve the health of the consumers. Limited information is available in South Africa related to the postharvest and nutrition loss in the urban fresh produce market supply chain. In this study, we quantified the postharvest losses, changes in phytochemicals, and loss of minerals in lettuce at different points of Tshwane Fresh Produce Market supply chain. Lettuce supply to the Tshwane Fresh Produce Market from two different provinces, Gauteng and North West, were included in this study for comparison. Lettuce from the two provinces was collected from five different farms. The loss of fresh weight, changes in visual quality, phytonutrition properties, and economic loss of lettuce at the supply chain points: (a) transport; (b) storage; (c) and at the retail shelf was investigated. Five boxes of lettuce per supply chain point from Gauteng and North West provinces were randomly selected. The results indicated that the high temperature (25°C) and low RH (40%) at the retail shelf affected the weight, overall quality, and phytonutrition properties of lettuce. Cumulative economic loss was higher at the retail shelf due to the inferior quality of lettuce. The study identified where major quality and phytonutrition losses occur during marketing. The study demonstrated to identify the where major food and nutritional loss losses occur during marketing. This information will significantly benefit food sustainability by introducing technologies to manage food and nutrition losses.

Deficit irrigation improves phenolic content and antioxidant activity in leafy lettuce varieties.

This study investigated the effect of deficit irrigation at three management allowable depletion levels (MAD) 25%, 50%, and 75% on phytochemicals, ascorbic acid, antioxidant activity, glucose, fructose, and fresh and dry mass in two green leafy lettuce cultivars (Lollo Bionda and Vera) at harvest. Genotype response was observed during deficit irrigation on fresh and dry mass at harvest. Vera revealed similar fresh mass at MAD levels 25% and 50%. Chicoric acid, caftaric acid, and chlorogenic and caffeic acid tended to increase at 50% MAD, while kaempferol, quercetin, and myricetin increased at 75% MAD in both cultivars indicating increasing antioxidant properties. Ascorbic acid content declined with increasing MAD levels and no definite trend on ß-carotene content was noted in these cultivars with respect to MAD irrigation. Deficit irrigation at 50% and 70% increased glucose concentration in cv. Lollo Bionda. Deficit irrigation influences the abiotic stress condition that stimulates the biosynthesis of phytochemicals in plants and improves crop quality. However, deficit irrigation can affect marketable crop yield. Based on findings of this study, the lettuce cv. Vera can be recommended as a suitable cultivar for deficit irrigation (at MAD 50% levels) for improving dietary phytochemicals and crop quality without compromising fresh mass for marketing.

Spectral quality of photo-selective nets improves phytochemicals and aroma volatiles in coriander leaves (Coriandrum sativum L.) after postharvest storage.

The influence of spectral light on leaf quality and phytochemical contents and composition of aroma compounds in coriander leaves grown for fresh use under photo-selective nets; pearl net [40% shading; and 3.88 blue/red ratio; 0.21 red/far red ratio; photosynthetic radiation (PAR) 233.24 (µmolm(-2)s(-1))] and red net [40% shading and 0.57 blue/red ratio; 0.85 red/far red ratio; 221.67 (µmolm(-2)s(-1))] were compared with commercially used black nets [25% shading; 3.32 blue/red ratio 0.96 red/far red ratio; 365.26 (µmolm(-2)s(-1))] at harvest and after 14days of storage. Black nets improved total phenols, flavonoid (quercetin) content, ascorbic acid content, and total antioxidant activity in coriander leaves at harvest. The characteristic leaf aroma compound decanal was higher in leaves from the plants under the red nets at harvest. However, coriander leaves from plants produced under red nets retained higher total phenols, flavonoids (quercetin) and antioxidant scavenging activity 14days after postharvest storage (0°C, 10days, 95% RH and retailers' shelf at 15°C for 4days, 75% RH). But production under the pearl nets improved marketable yield reduced weight loss and retained overall quality, ascorbic acid content and aroma volatile compounds in fresh coriander leaves after postharvest storage. Pearl nets thus have the potential as a pre-harvest tool to enhance the moderate retention of phytochemicals and saleable weight for fresh coriander leaves during postharvest storage.

Anti-proliferative properties of commercial Pelargonium sidoides tincture, with cell-cycle G0/G1 arrest and apoptosis in Jurkat leukaemia cells.

Context Pelargonium sidoides DC (Geraniaceae) is an important medicinal plant indigenous to South Africa and Lesotho. Previous studies have shown that root extracts are rich in polyphenolic compounds with antibacterial, antiviral and immunomodulatory activities. Little is known regarding the anticancer properties of Pelargonium sidoides extracts. Objective This study evaluates the anti-proliferative effects of a Pelargonium sidoides radix mother tincture (PST). Materials and methods The PST was characterized by LC-MS/MS. Anti-proliferative activity was evaluated in the pre-screen panel of the National Cancer Institute (NCI-H460, MCF-7 and SF-268) and the Jurkat leukaemia cell line at concentrations of 0-150 µg/mL. The effect on cell growth was determined with sulphorhodamine B and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays after 72 h. The effect on cell cycle and apoptosis induction in Jurkat cells was determined by flow cytometry with propidium iodide and Annexin V: fluorescein isothiocyanate staining. Results Dihydroxycoumarin sulphates, gallic acid as well as gallocatechin dimers and trimers were characterized in PST by mass spectrometry. Moderate anti-proliferative effects with GI50 values between 40 and 80 µg/mL were observed in the NCI-pre-screen panel. Strong activity observed with Jurkat cells with a GI50 value of 6.2 µg/mL, significantly better than positive control 5-fluorouracil (GI50 value of 9.7 µg/mL). The PST arrested Jurkat cells at the G0/G1 phase of the cell cycle and increased the apoptotic cells from 9% to 21%, while the dead cells increased from 4% to 17%. Conclusion We present evidence that P. sidoides has cancer cell type-specific anti-proliferative effects and may be a source of novel anticancer molecules.

Bioactive Compounds and Fruit Quality of Green Sweet Pepper Grown under Different Colored Shade Netting during Postharvest Storage.

UNLABELLED: In this study, influence of 3 types of photo-selective nets (pearl, red and yellow) and a standard black net on marketable yield, fruit quality and bioactive compounds after postharvest storage was investigated. Percentage marketable fruits were higher in green sweet peppers produced under the pearl nets. Fruits produced under the pearl nets showed higher fruit mass, firmness, chlorophyll content, ascorbic acid content, antioxidant scavenging activity after postharvest storage. Red/far red photon ratio under the pearl net could have improved the ascorbic acid content and the antioxidant scavenging activity in green peppers. Green sweet peppers grown under the pearl nets had higher hue values and maintained green color longer. Our results showed the impact of modified light quality on the bioactive compounds of green sweet pepper during postharvest storage. PRACTICAL APPLICATION: Green sweet peppers are rich in phytochemicals. Marketability of green sweet peppers is affected partially due to ripening after postharvest storage and decay. Maintenance of green color, fruit mass, firmness, and nutritional composition are important parameters that attract consumers. This research shows the influence of light quality during production on the fruit quality parameters and bioactive compounds after postharvest storage.

Postharvest responses of red and yellow sweet peppers grown under photo-selective nets.

Postharvest responses of red ('HTSP-3') and yellow ('Celaya') sweet pepper fruit yield, quality parameters and bioactive compounds (to three types of photo-selective nets and a standard black net) were investigated in this study. Red and yellow peppers produced under the black net retained higher ß-carotene, lower total phenolic contents and showed deep red and orange colour after storage. Both peppers produced under the pearl net retained a higher ascorbic content, antioxidant scavenging activity, fruit firmness and also reduced weight loss after storage. Red and yellow peppers grown under pearl and yellow nets resulted in a higher percentage of marketable fruit, after storage. Red pepper grown under the yellow net showed a higher number of odour active aroma compounds in the fruit, while black nets significantly affected the synthesis of odour active aroma compounds during storage. Sensory analysis indicated a preference for red pepper fruits after storage from plants grown under pearl nets.

Effect of photo-selective nettings on post-harvest quality and bioactive compounds in selected tomato cultivars.

BACKGROUND: Photo-selective coloured netting is referred to as a 'new agro-technological' concept adopted to manipulate light quality changes that can induce favourable responses in plants. RESULTS: Tomato (Solanum lycopersicum L.) cultivars AlvaV, Irit and SCX 248 grown under the black net (commercial net, 25% shading) showed higher weight loss, loss of firmness, ascorbic acid content and decline in the ratio of soluble solids content/titrable acidity during post-harvest storage (low-temperature storage at 10°C and 90% relative humidity for 21 days followed by market shelf conditions at 25°C for 2 days). During post-harvest storage, lycopene, ß-carotene, total phenolic content and antioxidant scavenging activity were higher in cvs AlfaV and Irit grown under the black or pearl nets. However, the ß-carotene, total phenolic content and antioxidant scavenging activity were higher in SCX 248 grown under the red net during post-harvest storage. Cultivar AlfaV grown under the red and pearl nets had a higher number of odour active aroma compounds during post-harvest storage. Panellists preferred cv. AlfaV grown under the pearl nets after storage based on taste, overall appearance and firm textured fruits. CONCLUSION: Pearl photo-selective nets retained the overall fruit quality and bioactive components in cvs AlfaV and Irit during post-harvest storage. Red photo-selective nets, however, showed greater influence on retention of overall fruit quality and bioactive compounds in cv. SCX 248 during post-harvest storage.

Thyme oil vapour and modified atmosphere packaging reduce anthracnose incidence and maintain fruit quality in avocado.

BACKGROUND: Postharvest application of prochloraz fungicide is commercially practiced to control anthracnose, a postharvest disease in avocado. Increasing consumer concern regarding food safety and demand for organically produced fruits make it necessary to search for natural environmentally friendly alternative products and processes for the fruit industry. RESULTS: A combination of modified atmosphere packaging (MAP; ∼8% CO2, 2% O2) plus thyme oil (TO) was evaluated on the incidence and severity of anthracnose, physiological disorders (grey pulp, vascular browning), fruit quality parameters (L*, h°, firmness, weight loss) and sensory parameters (taste, texture, flavour and overall acceptance), phenylalanine ammonia-lyase (PAL) enzyme activity, total phenolic compounds, flavonoid contents and antioxidant activity in avocados ('Fuerte' and 'Hass' cultivars) held at 10 °C cold storage for 18 days and thereafter, ripened at 25 °C for 5-10 days. Stand-alone MAP, commercial treatment (prochloraz 0.05%) and untreated (control) fruit were included for comparison. MAP + TO treatment significantly (P < 0.05) reduced the incidence and severity of anthracnose, grey pulp, vascular browning, weight loss and loss of fruit firmness, and showed acceptable taste, flavour, texture and higher overall acceptance, increased PAL activity, total phenolic compounds, flavonoid contents and antioxidant activity, after ripening at 25 °C followed by cold storage at 10 °C. CONCLUSION: This investigation recommends MAP + TO combination treatment as a suitable alternative to the currently adopted prochloraz application.