Bell Pepper Fruit Research Articles

Synergistic effect of polyamine treatment and chitosan coating on postharvest senescence and enzyme activity of bell pepper (Capsicum annuum L.) fruit

• Combination treatment of spermidine (SPD), spermine (SPM) and chitosan (Ch) as coating for extending shelf life of capsicum fruit. • Fruits were treated with coating solutions SPD and SPM @ 0.5, 1.0 and 1.5 mM, then coated with chitosan and stored at 10 ± 1 °C. • The biochemical parameters, enzymatic activities, antioxidant capacity and quality parameters were assessed in capsicum fruit during storage. • Spermine (1.5 mM) and chitosan 1% treatment showed the lowest weight loss and was adjudged best treatment to extend storability of capsicum fruit cv. “Rehana”. This study investigated the effects of treating bell pepper fruit cv. Rehana by dipping with spermidine and spermine (0.5, 1.0 and 1.5 mM) and coating with chitosan (1%) on fruit quality, bio-active compounds, antioxidant enzyme activities, shelf life and senescence related compounds. The fruit were stored at 10 °C and 80–90% RH for 56 days. The results revealed that synergistic treatment of spermine 1.5 mM and chitosan 1% (T7) was most effective for reducing weight loss, electrolyte leakage, maintaining fruit quality and enhancing antioxidant activity over other treatments during storage. The bell pepper fruit of T7 treatment exhibited lowered weight loss by 47.6%, electrolyte leakage by 62.6%, malondialdehyde accumulation by 28.3% while maintaining higher total phenols by 68.8%, total carotenoid by 21.9%, ascorbic acid by 15%, total chlorophyll by 30.4%, catalase activity by 34.3% in comparison to control (T1) on the last day of storage. Other treatments showed intermediate effects. The results suggest potential beneficial influence of synergistic treatment of polyamines, particularly spermine 1.5 mM with chitosan in extending shelf life of bell pepper by about 28 days relative to control with notable preservation of bioactive compounds, antioxidant enzymes and slowing senescence indicators over untreated fruit.

Mineral Nutrients, Physiological Disorders, Postharvest Water Loss, and PR Gene Expression in Bell Pepper (Capsicum annuum L.) Fruit under Shade Nets

Abstract Shade nets can be an effective technology for producing bell pepper (Capsicum annuum L.) under hot climatic conditions. However, the effects of shading on fruit quality are still unclear. The objectives were to evaluate the effects of shade level on fruit mineral nutrient content, physiological disorders, and postharvest water loss. Trials were conducted in the spring–summer of 2016, 2017, and 2018 in Tifton, Georgia, USA, following a randomized complete block design with five shade levels: 0% (open field), 30%, 47%, 63%, and 80%. Shading increased the bell pepper fruit dimensions (length, diameter, and weight) in 2016 and mineral nutrient content in 2017. Fruit sunscald incidence decreased with increasing shade level, while blossom-end rot showed inconsistent responses. Postharvest fruit water loss and transpiration rates were highest in fruits from the unshaded treatment in 2016; there were no differences in fruit water loss among the shade levels. NONEXPRESSOR OF PATHOGENESIS-RELATED 1 (NPR1) and PATHOGENESIS-RELATED 1 (PR1) genes expressed more than 1.5-fold and 10-fold, respectively, at 47% shade level compared to 80%, though not significantly. Therefore, plants grown under shading had fruit with greater size, increased mineral nutrient content, and reduced sunscald incidence compared with the unshaded control.

A freshness index for bell pepper fruit

A freshness index for bell pepper fruit

Sites of biosynthesis, distribution and phloem transport of 3-isobutyl-2-Methoxypyrazine in Capsicum annuum (bell pepper) plants

The distribution and translocation as well as the biosynthetic sites of 3-isobutyl-2-methoxypyrazine (IBMP) in bell pepper plants (Capsicum annuum) were examined. For IBMP-quantification, a stable-isotope dilution assay (SIDA) was developed, using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography and time-of-flight mass spectrometry (ToF-MS). While IBMP was the most abundant MP in all aerial plant parts, IPMP was dominating in root tissues. The highest IBMP-levels were found in unripe bell pepper fruits. Moreover, feeding experiments with [2H10]-l-leucine revealed that IBMP is biosynthesized in all plant parts, while in roots and ripe bell pepper fruit tissues no incorporation of the labelled precursor was detectable. A potential phloem translocation of IBMP could not be detected.

Influence of Feeding Natural and Synthetic Lycopene on Performance, Egg Quality and Serum Parameters of Japanese Quail Layers

Background: This study was conducted to investigate the effects of natural and synthetic sources of lycopene on performance, egg quality and some blood characteristics of Japanese quail layers. Methods: The 252 eight-week-old quail hens were randomly divided into seven treatments with three replication. The first treatment was fed basal diet (control). Second and third treatments were given diets containing tomato fruit powder (TOM) at a level of 17 and 34 g/kg equal to 50 and 100 mg/kg lycopene, fourth and fifth treatments were given red bell pepper fruit powder (RBP) at level 16.23, 32.46 g/kg equal to 50 and 100 mg/kg lycopene, while synthetic lycopene powder at a rate of 50, 100 (mg/kg) was supplemented to sixth and seventh respectively. Result: The final body (T4-T6), hen day egg production (except for T3 and T6), egg weight, egg mass (T4, T5), feed intake, FCR were improved as compared to control. Significant effect on the weight of eggshell, yolk, albumen and albumen (height and diameter). Yolk (height, diameter, index) improved as compared to control. Significant (P≤0.05) increase in total protein and HDL, while cholesterol (except T2 and T7), triglycerides (except T2) and LDL were decreased significantly (P≤0.05). It could be concluded that supplementary TOM, RBP and LY, have beneficial effects on laying performance, egg quality traits and some biochemical indices of quails.

Photoprotective, Anti-Fungal Activity and Cytotoxicity of Capsanthin from Capsicum Annum Fruits on Mouse Skin Melanoma and AQP-3 Gene Expression in Human Keratinocyte HaCaT Cells

Background: Phytochemicals utilization in the cosmetics are the current trend in the beauty and fashion. Most women prefer the cosmetics derived from natural products over synthetic chemicals, as the natural products are devoid of undesirable side effects. Skin protection has become not only aesthetic, but also linked to health. Therefore, exploring the use of phytochemicals in cosmetic dermatology is essential. Objective: In the current in vitro studies, we investigated the skin-protection properties of capsanthin 50%w/w crystals (CAP-50CR) and capsanthin 1.5% w/w soft extract (CAP-1.5SE) obtained from red bell pepper fruits, out of which one is an industrial by-product on sunburn, melanin inhibition, tyrosinase inhibition, anti-fungal activity and, gene expression of Aquaporin 3 (AQP-3) in the human keratinocyte cell line. Methodology: The two extracts, obtained by solvent extraction, super critical extract purification, saponification, characterized, and examined on their dermatological activities. Results: Capsanthin 50%w/w crystals (CAP-50CR) showed a sun protection factor (SPF) value of 34.44 whereas capsanthin 1.5% w/w soft extract (CAP-1.5SE) showed a value of 20.63. Minimal inhibitory concentration (MIC) of CAP-50CR against Malassezia furfur was 0.625 mg/mL and CAP-1.5SE showed a MIC of 5mg/mL. Both CAP-50CR and CAP-1.5SE showed the same MIC against Candida albicans which is 2.5 mg/mL. In the MTT assay on mouse skin melanoma cells (B16F10), the test substance CAP-50CR showed a CTC50 value of 98.44±2.55 µg/mL whereas the test substance CAP-1.5SE exhibited a CTC50 value greater than 1000 µg/mL. Further, the non-toxic concentrations of the test items were evaluated for forskolin-induced melanin inhibition activity. For CAP-50CR, the non-toxic concentration of 7 and 3 µg/mL showed the melanin inhibition of 48.73±0.75% and 42.29±5.2% and for CAP-1.5SE the melanin inhibition was found to be 55.84%±1.47 and 46.44%±1.05 for the non-toxic concentration of 50 and 25µg/mL. The CAP-50CR extract showed 43.78% and 39.37% tyrosinase inhibition at the tested concentrations of 7 and 3 µg/mL. Similarly, CAP-1.5SE showed the tyrosinase inhibitions as 34.6% and 22.9% for the concentrations of 50 and 25 µg/mL. The test substances CAP-50CR and CAP-1.5SE exhibited a CTC50 value of 76.59±3.25 μg/mL and 664.95±2.88 µg/mL on the HaCaT cells. In the gene expression study, both the test substances showed an increase in the levels of AQP-3 mRNAs at lower and higher concentrations as compared to the control in the semi-quantitative RT-PCR procedure. Conclusion: CAP-50CR and CAP-1.5SE showed skin protection from UV radiation and hyperpigmentation. Also exhibits anti-fungal, skin brightening, anti-wrinkle and moisturizing properties. These results suggests that capsanthin from red bell pepper fruit can be employed as cosmetic active ingredient in skin guard formulations and as a potential therapeutic agent for variety of dermatological disorders. This study breaks new ground by investigating the potential of capsanthin in the management of skin protection for the first time.

First Report of Fruit Rot of Sweet Pepper Caused by Cladosporium cladosporioides in Israel.

Sweet pepper (Capsicum annuum L.) is an important vegetable crop grown in Israel for local and export markets. Bell pepper 'Dinamo' and sweet bite pepper exhibiting fruit spotting were observed in postharvest storage of commercial farms in Giv'at Ko'ah (32°02'21″ N; 34°56'41″ E) and Arava (30°46'41″ N; 35°14'28″ E) in July, 2021. Fruit with lesions were sporadic at each facility, however, limited numbers of packaged boxes were discarded due to a high percentage of symptomatic fruit. The spots appeared as slightly sunken dark brown or black lesions, coated by a fine velvety layer of olive-grey conidia (Suppl. Fig. 1). A fungus was routinely isolated from the fruit onto potato dextrose agar amended with 50 ppm chloramphenicol (PDAC) and was tentatively identified as a Cladosporium spp. based on colony morphology and conidial appearance (Suppl. Fig. 1). Isolates (n = 6) of the fungus were cultured on malt extract agar (MEA) and PDA for morphological observation. On MEA, the pathogen sporulated profusely and conidia measured 4.5 (3 - 7) × 3.5 (2 - 4) µm and were smooth and globose or sub-globose. Ramoconidia had 0 or 1 septations and measured 13.4 (10 - 18) × 3.9 (3 - 6) µm. Conidiophores were solitary, straight or flexous, usually unbranched, and measured 60 - 350 µm. Both macro- and micronematous conidiophores were present. Hyphae were flat and immersed, olivaceous-grey, septate and rope-like. The fungus was slow growing, reaching 41.0 mm after 10 d incubation at 20°C. To confirm species identity, the isolates were grown in potato dextrose broth and DNA was extracted from the mycelium using MasterPure DNA Purification Kit (EpiCentre, Madison, WI, USA) following the manufacturer's instructions. The internal transcribed spacer (ITS) region was amplified using primers ITS 1 and ITS 4, and elongation factor-1 and actin gene regions with EF1-728F/986R and ACT-512F/783R, respectively (Carbone and Kohn, 1999). The PCR products were sequenced and a BLASTn search showed 99-100% similarity to Cladosporium cladosporioides (GenBank accession nos. MW255614.1, MK416093.1, MK306457.1), a common fungal species found worldwide as a plant pathogen and saphrophyte (Bensch et al., 2012). The ITS gene sequences for a representative isolate from each location were deposited in GenBank (accession nos. OK104139.1 and OL672241.1). To confirm pathogenicity, red bell pepper fruits (n = 8) were wounded with a sterile needle and a 12 µl drop of conidial suspension (4 x 105/ml) of each isolate was pipetted onto the wound. Control fruit received sterile water. The fruit were incubated at 100% RH in sealed containers at 20-22°C. After 7-10 d incubation small dark sunken spots developed, and by 14 d lesions formed with velvety conidial growth similar to the ones originally observed. The fungus was successfully isolated again from the lesions onto PDA and confirmed as C. cladosporioides based on colony and conidial morphology. No symptoms developed on fruit inoculated with sterile water. The pathogenicity test was repeated two times with similar results. C. cladosporioides is a cosmopolitan pathogen and has been cited causing disease on numerous crops worldwide (Bensch et al., 2012). This species was reported causing tomato leaf spot in Mexico (Robles-Yerena et al., 2019) and black mould of tomato fruit in Australia (Ma et al., 2020). Cladosporium herbarum was found causing fruit rot of bell pepper in the U.S. (Ramsey and Heiberg, 1952). Sweet peppers are widely grown in Israel, and have high economic value as an export crop. Control measures to limit losses from C. cladosporioides postharvest may be necessary if conditions are favorable for disease during prolonged storage and refrigerated transport.

Combating Horticultural Misinformation through Integrated Online Campaigns Using Social Media, Graphics Interchange Format, and Blogs

Misinformation relating to horticulture can spread quickly among laypersons. Although some misinformation may be harmless, such as the myth that bell pepper (Capsicum annuum) fruit can be either male or female, other misinformation is generated to sway consumer decisions. The demand from Cooperative Extension Service (CES) agents for support to combat the spread of horticultural misinformation, horticulture specialists at the University of Arkansas System Division of Agriculture Cooperative Extension Service (UACES) created a “Horticulture Fact or Fiction” series of blog posts that targeted common horticulture myths with science-based explanations and used graphics interchange format (GIFs) to promote the blog posts on social media. The integrated social media campaign was shared on the authors’ UACES Horticulture social media accounts and by eight UACES agents during 2021. The effort reached 13,397 social media users, and the blog posts had a total of 45,544 pageviews. Although social media was not the major driver of traffic to the blog post series, GIF-based outreach on social media did direct more than 1000 additional users to the blog posts. Through this integrated approach of using social media and GIFs shared by both specialists and CES agents, we were able to connect a large number of stakeholders to research-based content, resulting in higher average traffic to our webpage-based blogs than the average UACES webpage. This type of integrated approach using multiple online means of communication including GIFs, blogs, and social media to create a toolkit of resources for CES agents may be useful for extension professionals targeting stakeholders online.

Immersion in hot water as a phytosanitary treatment for Thaumatotibia leucotreta (Lepidoptera: Tortricidae) in bell pepper (Capsicum annuum L.)

The False codling moth (FCM), Thaumatotibia leucotreta is a major quarantine pest that hampers Capsicum production and trade in sub-Saharan Africa (SSA) and may need a postharvest treatment to meet quarantine standards of lucrative overseas markets. In this study, we evaluated the efficacy of hot water treatment (HWT) as a potential nonchemical quarantine control option against T. leucotreta in bell pepper and its effect on the quality parameters of the peppers. Infested bell pepper harboring different immature stages of T. leucotreta were subjected to a hot water treatment of 50 ± 0.2 °C for eight different time-points to determine heat susceptibility of immature stages of T. leucotreta. The third-instar was the least heat susceptible, followed by second-and first-instar larva and the egg stage, respectively. The immersion time of 44.23 min (95% CL 43.22 – 45.24) was estimated to be the minimum time required to attain 99.9968% control level. In the large scale confirmatory experiment, there were no survivors from the 20,325 third instar individuals treated in bell pepper (180 – 220 g). Additionally, none of the 25,384 third instars exposed to 50 ± 0.2 °C for 32 min survived. The impact of the HWT schedule on bell pepper fruit quality parameters was assessed and there were no significant effects on weight loss, moisture content, total soluble solids, titratable acidity, dry matter and pH post treatment. These results provide strong evidence that the HWT schedule is an effective phytosanitary treatment for control of T. leucotreta, and may be adopted to facilitate access to overcome the phytosanitary barriers imposed by importing countries to capsicum from SSA.

Improving Bell Pepper Crop Performance and Fruit Quality under Suboptimal Calcium Conditions by Grafting onto Tolerant Rootstocks

Calcium deficiency or its inefficient translocation to pepper fruits leads to considerable economic loss by reducing the number of marketable fruits. The present study proposes grafting as an environmentally friendly technique to effectively reduce such loss. A commercial variety (Al-cudia F1; V) was grafted onto two pepper (Capsicum annum L.) accessions (V/A6 and V/A8), a hybrid rootstock (V/N) and was also self-grafted (V/V). All rootstock–scion combinations were cultivated under greenhouse conditions with optimal and suboptimal Ca supply and assessed for fruit yield and biomass production, gas exchange and chlorophyll fluorescence, mineral concentration in leaves and fruits as well as several fruit quality parameters. The V/N plants demonstrated an enhanced capacity for increased biomass, higher yield and number of commercial fruits and greater mean fruit weight compared with the other rootstock–scion combinations. These improvements are attributed primarily to increased intrinsic water efficiency. Additionally, a significantly higher Ca concentration in leaves was found under suboptimal Ca conditions in the V/N combination than that found in the other rootstock–scion combinations indicating a higher capacity for Ca uptake and translocation. Under the same conditions, the concentration of organic acids in fruits, such as citric and tartaric, which impact the organoleptic quality, was also higher in V/N plants. Consequently, we can conclude that grafting pepper onto tolerant rootstocks is a successful tool for ameliorating the negative impact of suboptimal Ca conditions on pepper crop performance and fruit quality.

Streptomyces consortium improved quality attributes of bell pepper fruits, induced plant defense priming, and changed microbial communities of rhizosphere under commercial greenhouse conditions

Although many studies have shown the positive effect of PGPRs on the yield and quality characteristics of crops, only a few are successful in commercial greenhouses. This study aimed to evaluate the efficiency of PGP-Streptomyces in commercial greenhouse conditions. Greenhouse trials were done with four treatments including strains SS12, Y17, an effective combination of strains SS14 and IT20, and a commercially available bio-fertilizer (Barvar NPK®) on two cultivars of bell pepper. Treatment with strain SS12 improved the yield of green (26%) and orange (5%) bell pepper compared to the control while SS14 + IT20 increased only the yield of green pepper (23%). The score value of overall acceptance obtained from the sensory evaluation of orange bell peppers treated with SS14+ IT20 was the highest, following the higher score values of quality properties including appearance, flavor, smell, and juiciness. Treatments of Barvar and SS14+ IT20 reduced the nitrate content of both cultivars by about 32–41% and based on the analysis of variances, SS14+ IT20 was more effective than Barvar. Lower concentrations of fruit sugar without affecting its acceptance and higher levels of micronutrients Ca, Zn, and Fe indicate the higher nutritional value of SS14+ IT20 -treated peppers. Increased expression of defense genes ERF and PR1 and higher activity of antioxidant enzymes in SS14+ IT20 and Barvar showed that treated plants are ready to deal with possible pathogens that cause damage in commercial greenhouses. The results of this study showed for the first time that PGP-Streptomyces can be effective in commercial bell pepper greenhouses.

Investigation of Biosynthetic Precursors of 3-Isobutyl-2-Methoxypyrazine Using Stable Isotope Labeling Studies in Bell Pepper Fruits (Capsicum annuum L.).

The biosynthesis of 3-isobutyl-2-methoxypyrazine (IBMP) in bell pepper fruits (Capsicum annuum L.) was investigated by in vivo feeding experiments with stable isotope-labeled precursors. Volatiles were extracted using headspace solid-phase microextraction (HS-SPME) and analyzed by comprehensive two-dimensional gas chromatography (GC×GC) coupled to a time-of-flight mass spectrometer (ToF-MS). Feeding experiments revealed incorporation of l-leucine and α-ketoisocaproic acid (α-KIC) as well as glycine and glyoxylic acid into IBMP. Furthermore, it has been shown that de novo biosynthesis of IBMP occurs in pericarp tissues of unripe bell pepper fruits, whereas pericarp tissues of ripe bell pepper fruits showed no capability of IBMP biosynthesis.

Effect of Fruit Weight and Fruit Locule Number in Bell Pepper on Industrial Waste and Quality of Roasted Pepper

Bell pepper (Capsicum annuum L.), one of the most consumed vegetables worldwide, shows great differences between its diverse varieties. These differences affect the fruit type, size and shape. Food preservation techniques prolong the availability of sweet pepper. Roasted pepper is a product marketed with the European recognition of Protected Geographical Indication ‘Pimiento Asado del Bierzo’. The objective of this work was to analyse the effect of the fruit weight and fruit locule number of the industrial fresh pepper on quality and roasted pepper yield. Large trilocular fruits and large tetralocular fruits reached higher roast yield and uniformity than small trilocular fruits. Regardless of fruit locule number and fruit weight, the overall quality of all the samples of roasted pepper was categorised as very good. Large tetralocular and large trilocular fruits are the most appropriate peppers for industrial purposes, whereas small trilocular fruits should be intended for the fresh product market. This easy method of sorting bell pepper fruit attending to fruit weight will decrease the amount of pepper waste in the industrial roasting process (around 18%), while maintaining the high overall quality of the final product. Moreover, the faster peeling of large peppers will also contribute to increasing the productivity of the industrial processing of roasted pepper.

Perforated modified atmosphere packaging differentially affects the fruit quality attributes and targeted major metabolites in bell pepper cultivars stored at ambient temperature

• Yellow and red bell pepper fruit were treated with perforated MAP at 22°C for 3 weeks. • MAP reduced weight loss and delayed any reduction in firmness. • MAP decreased the levels of SSC and soluble carbohydrates. • MAP reduced the levels of proline and GABA. • The fatty acid response was not affected by MAP but by the cultivar. Bell pepper quality can deteriorate during distribution and storage, and often develop disorders. Thus, the effectiveness of micro perforated modified atmosphere packaging (MAP) technology on targeted metabolites associated with fruit quality and physiological disorders in ‘Volante’ and ‘Sirocco’ bell pepper cultivars was investigated over a period of up to 3 weeks at 22 °C. The perforated MAP reduced weight loss and retained pericarp firmness. The soluble solids and carbohydrates, and organic acid contents were lower in the perforted MAP-treated fruits than untreated fruits. Fruit shriveling decreased after MAP treatment. In both cultivars, proline and gamma-aminobutyric acid (GABA) levels were lower in MAP-treated fruits than in untreated fruits of both cultivars. Fatty acid levels were not affected by the perforated MAP treatment but were influenced by the cultivar and storage time especially in ‘Volante’. Overall, the results indicate that the micro perforated MAP treatment can suppress weight loss and retain pedicel firmness, reducing the bell pepper shriveling at ambient temperature and thus prolonging their shelf life.

Effect of non-destructive edible coating materials and refrigerated storage on quality and shelf life of bell pepper (Capsicum annuum)

Bell pepper (Capsicum annuum L.) has high nutritional value but the high water content makes it susceptible to water loss and shrivelling, limiting the storage life. The present investigation was carried out at the post-harvest physiology laboratory of Dr Y S Parmar University of Horticulture and Forestry, Nauni, Himachal Pradesh in 2017–18 to evaluate the effect of various edible coatings on the quality of capsicum fruits. Comparative mean analysis by Tukey’s test (P<0.05) revealed that the coated fruits exhibited lesser variations in various physico-chemical characteristics during storage while, 50% and 25% starlight coating and 15% Aloe vera leaf extract resulted in delayed senescence and were effective in maintaining the postharvest quality of green bell pepper fruits.

Integrated Treatments between Some Essential Oils and Chitosan for Controlling Gray Mold Disease of Bell Pepper Fruits during Storage

Integrated Treatments between Some Essential Oils and Chitosan for Controlling Gray Mold Disease of Bell Pepper Fruits during Storage

Cold shock treatment with oxalic acid could alleviate chilling injury in green bell pepper by enhancing antioxidant enzyme activity and regulating proline metabolism

The effects of cold shock, oxalic acid, and combined cold shock + oxalic acid treatments on chilling injury, antioxidant enzyme activity, and proline metabolism of cold-stored green bell pepper fruit were investigated. The results showed that cold shock, oxalic acid treatment, and their combination significantly reduced chilling injury, inhibited the increase of superoxide radical production, hydrogen peroxide content, malondialdehyde levels, and relative membrane permeability, and increased antioxidant enzyme activity. Furthermore, the treatments promoted the accumulation of proline associated with increase in ∆1-pyrroline-5-carboxylate synthetase and ornithine δ-aminotransferase activities, and decrease in proline dehydrogenase activity. The results indicate that cold shock, oxalic acid, and their combination alleviated chilling injury in green bell pepper fruit by increasing antioxidant enzyme activity and proline accumulation. The combined cold shock + oxalic acid treatment was the most effective method for reducing chilling injury, and therefore has broad future application prospects.

Multi-omics analysis reveals specific modifications associated with reduced chilling injury in bell pepper fruit by methyl jamonate

Bell pepper is prone to chilling injury during cold storage. In this study, the plant hormone, methyl jasmonate (MeJA), which can stimulate the expression of plant defense genes, was used to investigate its effects on the transcriptome, metabolome and proteome after 6 days at 4 ℃. Differentially expressed (DE) mRNAs that were identified with plant hormone signaling included the transcription factor MYC2, and those associated with antioxidant properties, membrane lipids and cell wall modification, fruit quality and an important transcription factors pathway -- calmodulin-binding transcription activator - c-repeat-binding factor - transcription factor ICE1 (CMAT-CaCBF1A-ICE1). Effects on the proteome analysis were mainly associated with glutathione metabolism, biosynthesis of unsaturated fatty acids and fatty acid metabolism. Differentially expressed metabolites were identified as acids, phenolics, and capsaicin. Our study suggests that MeJA treatment mitigates chilling injury of bell peppers though inhibiting the MYC2-JA signaling pathway, enhancing the ASA-GSH cycle, reducing membrane lipid damage, suppressing cell wall disassembly, and activating the CMAT-CBF-ICE pathway. These results provide a theoretical basis for further study on chilling injury of bell pepper fruit.

Antioxidant enzymatic changes in bell pepper fruit associated with chilling injury tolerance induced by hot water.

Green bell pepper is highly susceptible to low temperature. The activation of the enzymatic antioxidant system plays a determining role in tolerance to chilling injury (CI). Immersion in hot water for short time previous to storage at low temperature induces tolerance to this disorder. However, there is a lack of information about the induction of chilling tolerance in bell pepper by hot water and its relationship with the enzymatic antioxidant system. We evaluated the effect of three immersion times (T, 1-, 2-, 3-min) in hot water (HW, 53°C) on the reduction of CI in bell pepper and its relationship with the enzymatic antioxidant system during storage at 5°C and 21°C. The use of hot water for 1-, 2- or 3-min reduced the decay and CI indexes, maintained quality parameters, ascorbic acid, and total phenolics content. The storage at 5°C by itself activated the enzymatic antioxidant system. The use of HWT 1-, 2-, and 3-min helped to increase this effect, especially by HWT2 . PRACTICAL APPLICATIONS: The application of a treatment with hot water for short times in fruit sensitive to chilling injury is undoubtedly a viable alternative to increase their tolerance and commercialization. In this study, the application of a hot water treatment for 1-, 2- or 3-min in bell pepper reduced the deterioration and susceptibility to chilling injury and stimulated the enzymatic antioxidant system. In this sense, agricultural producers can take advantage of this treatment to prolong the storage period of the fruit maintaining its quality and improving its commercialization.

Development of a Freshness Index for Fruit Quality Assessment—Using Bell Pepper as a Case Study

(1) Background: This special issue contains new developments in the field of fresh produce quality. Freshness provides the appeal for the consumer to purchase a particular horticultural produce. Freshness is a combination of size, colour, shape, flesh firmness, turgescence and glossiness without wilting, which imply that the produce has been picked only a short while ago and has not suffered any decay during harvest, transport or storage. (2) Objective: The objective of the present work was to develop potential freshness indices. The indices are based on non-invasive, real-time measurements, using changes in surface appearance after harvest, using Bell pepper as the most difficult model. (3) Methods: The selection criteria were a dramatic change in values over 14 days of storage at 17 °C, and either a consistent decrease or increase without peaks and troughs. Only two (out of five) non-invasive techniques were selected, i.e., surface glossiness, measured non-destructively using a luster sensor (type CZ-H72 from Keyence Co., Osaka, Japan) and light reflection spectra, recorded by a spectrometer, whereas the three techniques fruit firmness (penetrometer), colorimeter (e.g., Minolta) and false colour images (profilometer) were excluded. (4) Results: The first technique based on fruit glossiness provides luster values depending on fruit colour. Green Bell pepper fruit with a Fresh Index in excess of 463–490 a.i. can be classified as fresh, and similarly of 525–565 a.i. for yellow and 486–502 a.i. for red pepper fruit. This first Freshness index dropped, indicating a lesser freshness, to less than 100 a.i. after 14 days storage, irrespective of fruit colour, thereby providing a suitable wide, ca. 5-fold, range of parameterization. The second index is based on the difference between the light reflectance peaks at 630–633 nm and at 500 nm, also measured perpendicular to the convex fruit side. These percentage values decreased from >40% with fresh red and yellow Bell pepper to ca. 20% after 14 days storage; similarly, these percentages decreased from ca. 16% to ca. 8% in green pepper fruit, in both cases by a twofold factor. Overall, a third Freshness index could be a combination of luster values larger than 470 a.u. and >40% difference of the light reflectance between 630 nm and 500 nm. (5) Conclusions: Two viz three freshness indices are proposed and thresholds elaborated for Bell pepper fruit. The analysis showed that both indices viz technologies, luster and light reflection spectra, require colour differentiation, i.e., a specific index for yellow, red and green Bell pepper fruit.