Assessment of carotenoids, capsaicinoids and ascorbic acid composition of some selected pepper cultivars (Capsicum annuum L.) grown in Turkey

Green Ultrasound-Assisted Extraction of Bioactive Compounds from Cumari-Do-Pará Peppers (Capsicum chinense Jacq.) Employing Vegetable Oils as Solvents

Capsaicin, carotenoids, and phenolic compounds from cumari-do-Pará peppers (Capsicum chinense Jacq.) harvested from two different locations in Pará, Brazil, and at different ripening stages were extracted by employing green methodologies as an alternative to organic solvents. Edible vegetable oils from soybeans (Glycine max), Brazilian nuts (Bertholettia excelsa H.B.), and palm olein were used in combination with ultrasonic-assisted extraction (UAE). The proximate composition of the pepper extracts and vitamin C were determined through AOAC methods, total phenolics and carotenoids were assessed by UV/Vis spectrophotometry, and capsaicin by high-performance liquid chromatography. Antioxidant cumari-do-Pará extract activities were evaluated by the ABTS radical scavenging and β-carotene/linoleic acid assays. The vegetable oils were suitable for extracting and preserving bioactive pepper compounds, especially mature ones harvested from Igarapé-Açu. Bioactive compound content and antioxidant activity varied with harvesting location and ripening stage. Soybean oil was the most effective in extracting bioactive pepper compounds, particularly carotenoids, with 69% recovery. Soybean oil extracts enriched in capsaicin, carotenoids, and phenolics obtained from cumari-do-Pará can be used as spices in foodstuffs and/or as additives in pharmaceutical and nutraceutical formulations. Edible vegetable oils combined with UAE are promising for bioactive compound extraction, representing an environmentally friendly, safe, low-cost, versatile, and fast alternative.

Anti-Candida Potential of Peptides from Immature and Ripe Fruits of Capsicum chinense Jacq

The objective of this work was to purify and evaluate the antifungal potential of peptides present in immature and ripe fruits of Capsicum chinense Jacq. (accession UENF 1706) on the medical importance yeasts. Initially the proteins of these seedless fruits were extracted, precipitated with ammonium sulfate at 70% saturation, followed by heating at 80 °C. Subsequently, the peptide-rich extract was fractionated by DEAE-Sepharose anion exchange. The whole process was monitored by tricine-SDS-PAGE. The results revealed that the fraction retained in anion exchange column, called D2, of immature and ripe fruits significantly inhibit the growth of Candida albicans and C. tropicalis yeasts. Due to the higher yield, the D2 fraction of immature fruits was selected for further purification by reverse phase chromatography on HPLC, where sixteen different fractions (H1-H16) were obtained and these were subjected to antifungal assay at 50 µg mL-1. Although almost all fractions tested had significant growth inhibition, the HI9 fraction inhibit 99% of the two yeasts tested. The effect of treatment with HI3, HI8, HI9, and HI14 fractions on the viability of yeast cells was analyzed due to their strong growth inhibition. We observed that only 50 μg mL-1 of the HI9 fraction is the lethal dose for 100% of the cells of C. albicans and C. tropicalis in the original assay. Although the HI9 fraction had a fungicidal effect on both tested yeasts, we only observed membrane permeabilization for C. tropicalis cells treated with 50 µg mL-1 of this fraction. Through mass spectrometry, we identified that the 6 kDa peptide band of HI9 fraction showed similarity with antimicrobial peptides belonging to the plant defensin family.

A review of extraction and quantification of capsaicin and its bio insecticidal activity in food grains

Chili peppers pungent and spicy flavor is caused by capsaicin, which is one of their active components. As well as being an important aspect of fruit quality, the hot sensation is a key attribute linked to members of the Capsicum genus. Extraction is one of the most popular techniques for separating and purifying organic materials, but the technique must be quick, affordable, adaptable, efficient, and high performing. This review formulates the extraction of Capsaicin from chili peppers. The extraction methods used were solvent extraction (SE), ultrasound assisted extraction (UAE), microwave assisted extraction (MAE), enzymatic treatment, supercritical fluid extraction (SFE), solid phase microextraction (SPME), aqueous two phase system (ATPS) and liquid under pressure (PLE). The content of capsaicin in the extract was evaluated by using Thin Layer Chromatography (TLC), Fourier Transform Infrared Spectroscopy (FTIR) and High performance Liquid Chromatography (HPLC). The insecticidal activity of capsaicin in storage insects in food grains for shelf life enhancement and bio availability of capsaicinoids in terms of absorption, distribution, metabolism, and elimination were also discussed.

Capsicum chinense var. BRS Moema: chemical characterization by HPLC-ESI-MS/MS and antiproliferative screening

Capsiate and phenolics present in the free, esterified, glycosylated, and insoluble-bound forms of BRS Moema peppers were characterized and quantified using UHPLC-ESI-MS/MS. Additionally, the in vitro antiproliferative activity of BRS Moema extract was evaluated. The peppers showed considerable quantities of capsiate and phenolic compounds. Esterified phenolics were the main fraction, followed by the insoluble-bound fraction, indicating that relying solely on the extraction of soluble phenolics may underestimate the total phenolic content. Among the fourteen phenolics identified in extract fractions, gallic acid was the major constituent. Phenolic fractions displayed high antioxidant capacity by TEAC and ORAC assays. Nevertheless, the correlation between phenolic compounds and antioxidant activity suggested that other bioactive or phenolic compounds may contribute to the overall phenolic compounds and antioxidant capacity of the obtained fractions. Concerning the antiproliferative activity, the extract did not exhibit any effect on cell proliferation within the evaluated concentration range. These findings indicated that BRS Moema peppers can serve as a rich source of phenolic compounds. Therefore, fully utilizing them could bring advantages to the food and pharmaceutical industries, as well as to consumers and producers.

The Genus Capsicum: A Review of Bioactive Properties of Its Polyphenolic and Capsaicinoid Composition

Chili is one of the world's most widely used horticultural products. Many dishes around the world are prepared using this fruit. The chili belongs to the genus Capsicum and is part of the Solanaceae family. This fruit has essential biomolecules such as carbohydrates, dietary fiber, proteins, and lipids. In addition, chili has other compounds that may exert some biological activity (bioactivities). Recently, many studies have demonstrated the biological activity of phenolic compounds, carotenoids, and capsaicinoids in different varieties of chili. Among all these bioactive compounds, polyphenols are one of the most studied. The main bioactivities attributed to polyphenols are antioxidant, antimicrobial, antihyperglycemic, anti-inflammatory, and antihypertensive. This review describes the data from in vivo and in vitro bioactivities attributed to polyphenols and capsaicinoids of the different chili products. Such data help formulate functional foods or food ingredients.

Protective effects of Capsicum fruits and their constituents on damage in TNF-α-stimulated human dermal fibroblasts

BACKGROUND

Antioxidant and anti-inflammatory effects of natural products on skin cells have been proved to be effective in improving skin damage. Capsicum species contain capsaicinoids that have antioxidant and anti-inflammatory properties, and various subspecies are cultivated. In this study, the effects of four Capsicum fruits and major constituents on oxidative stress and inflammatory reactions were measured using human dermal fibroblasts (HDFs) to verify their effects on skin damage.

RESULTS

The inhibitory effects of nitric oxide (NO), reactive oxygen species (ROS), and prostaglandin E₂ (PGE₂ ) by cucumber hot pepper, red pepper (RDP), Shishito pepper (SSP), and Cheongyang pepper were determined in HDFs. RDP and SSP inhibited the production of NO, ROS, and PGE₂ in tumor necrosis factor-alpha-stimulated HDFs. Additionally, SSP seeds restored tumor necrosis factor-alpha-induced increase in matrix metalloproteinase-1 and decreased procollagen I α1 (COLIA1). In high-performance liquid chromatography analysis of the capsaicinoids capsaicin (CAP) and dihydrocapsaicin (DHC), CAP was detected at a higher level than DHC in the peel and seeds of all four types of Capsicum fruits, and the total amount of capsaicinoids was the highest in SSP. CAP and DHC, which are major constituents of Capsicum fruits, also inhibited NO, ROS, and PGE₂ and restored matrix metalloproteinase-1 and procollagen I α1.

CONCLUSION

RDP and SSP were shown to have a significant protective effect on skin damage, including oxidative stress, inflammatory reactions, and reduction of collagens. Capsaicinoids CAP and DHC were proved as active constituents. This research may provide basic data for developing Capsicum fruits as ingredients to improve skin damage, such as inflammation and skin aging. © 2022 Society of Chemical Industry.

Widely targeted metabolomic, transcriptomic, and metagenomic profiling reveal microbe-plant-metabolic reprogramming patterns mediated by Streptomyces pactum Act12 enhance the fruit quality of Capsicum annuum L

Plant growth-promoting rhizobacteria, such as Streptomyces pactum Act12, promote crop growth and stress resistance, but their contribution to fruit quality is still poorly understood. Herein we conducted a field experiment to ascertain the effects of S. pactum Act12-mediated metabolic reprogramming and underlying mechanisms in pepper (Capsicum annuum L.) fruit based on widely targeted metabolomic and transcriptomic profiling. We additionally performed metagenomic analysis to elucidate the potential relationship between S. pactum Act12-mediated reshaping of rhizosphere microbial communities and pepper fruit quality. Soil inoculation with S. pactum Act12 considerably increased the accumulation of capsaicinoids, carbohydrates, organic acids, flavonoids, anthraquinones, unsaturated fatty acids, vitamins, and phenolic acids in pepper fruit samples. Consequently, fruit flavor, taste, and color were modified, accompanied by elevated contents of nutrients and bioactive compounds. Increased microbial diversity and recruitment of potentially beneficial taxa were observed in inoculated soil samples, with crosstalk between microbial gene functions and pepper fruit metabolism. The reformed structure and function of rhizosphere microbial communities were closely associated with pepper fruit quality. Our findings indicate that S. pactum Act12-mediated interactions between rhizosphere microbial communities and pepper plants are responsible for intricate fruit metabolic reprogramming patterns, which enhance not only overall fruit quality but also consumer acceptability.

The Effect of the Varietal Type, Ripening Stage, and Growing Conditions on the Content and Profile of Sugars and Capsaicinoids in Capsicum Peppers

Peppers (Capsicum sp.) are used both as vegetables and/or spice and their fruits are used in a plethora of recipes, contributing to their flavor and aroma. Among flavor-related traits, pungency (capsaicinoids) and lately volatiles have been considered the most important factors. However, the knowledge of sugars is low, probably due to the fact peppers were historically considered tasteless. Here, using HPLC, we studied the content and profile of major sugars and capsaicinoids in a comprehensive collection of varietal types (genotype, G), grown under different growing systems (environment, E) in two years (Y) and considered the two main ripening stages (R). We found a major contribution to the ripening stage and the genotype in total and individual sugars and capsaicinoids. The year was also significant in most cases, as well as the G × E and G × Y interactions, while the growing system was low or nil. Ripening increased considerably in sugars (from 19.6 to 36.1 g kg^-1 on average) and capsaicinoids (from 97 to 142 mg kg^-1 on average), with remarkable differences among varieties. Moreover, sugars in fully ripe fruits ranged between 7.5 and 38.5 g kg^-1 in glucose and between 5.2 and 34.3 g kg^-1 in fructose, and several accessions reached total sugars between 40 and 70 g kg^-1, similar to tomatoes. The results reveal the importance of the genotype and the ripening for these traits, particularly sugars, which should be considered key for the improvement of taste and flavor in peppers.

Separation of nordihydrocapsiate from capsiate and major capsaicinoid analogues using ultra high performance liquid chromatography

Accurate, rapid quantitation of the capsaicinoid and capsinoid compounds produced by peppers (Capsicum spp.) is essential to assess quality. Here, we developed a rapid ultra-high performance liquid chromatography method for the simultaneous separation of five major capsaicinoids and three major capsinoids from peppers. Optimal chromatographic separation was achieved using a phenyl-hexyl stationary phase with a mobile phase of acidified water and methanol with a flow rate of 0.5 ml/min at a column temperature of 55 °C over 5 min. The method was validated by testing linearity, precision, robustness, and limits of detection and quantification. The developed method was successfully employed to profile capsaicinoids and capsinoids from different pepper cultivars. Out of the 10 pepper cultivars analysed, all three major capsinoids were detected in two cultivars. To the best of our knowledge, this is the first report of successful separation of nordihydrocapsiate from capsiate and quantification of nordihydrocapsiate.

Antioxidant and Antimicrobial Activity of Rosemary (Rosmarinus officinalis) and Garlic (Allium sativum) Essential Oils and Chipotle Pepper Oleoresin (Capsicum annum) on Beef Hamburgers

The inclusion of natural ingredients to preserve meat and meat products has increased in recent years. This study evaluated rosemary (REO) and garlic essential oils (GEO) as well as chipotle pepper oleoresin (CPO), alone or in combination, as preservatives on beef hamburgers (BH). Six treatments were evaluated: T1 (control, without additives), T2 (GEO 1%), T3 (REO 1%), T4 (CPO 0.5%), T5 (GEO 1% + CPO 0.5%) and T6 (REO 1% + CPO 0.5%). The microbiological quality, physicochemical characteristics, sensory evaluation, and lipid oxidation of hamburgers were evaluated. REO, GEO and CPO limited the growth of aerobic microorganisms, S. aureus, Salmonella spp., B. thermosphacta, moulds and yeasts, lactic acid bacteria and coliforms (p < 0.05); however, this effect depended on time. Furthermore, lipid oxidation decreased significantly (p < 0.5) in all treatments, except for T5 (GEO 1% + CPO 0.5%). Regarding sensory acceptance, consumers preferred BH with GEO in terms of colour, odour, flavour and overall appearance (p < 0.05). It is concluded that REO, GEO and CPO, alone or in combination, improve microbiological quality and inhibit the lipid oxidation of BH.

Application of far-infrared radiation for sun-dried chili pepper (Capsicum annum L.): drying characteristics and color during roasting

BACKGROUND

Chili is hygroscopic and needs a fast-drying method before feeding into pulverizers. The far-infrared radiation (FIR) roasting technique provides various benefits, such as higher drying rates within a short duration, reduction of mycotoxins, and improvement in the textural quality of agricultural produce. In addition, thin-layer modeling supports understanding the drying kinetics of agricultural produce. Therefore, the objective of this research was to study the thin-layer drying characteristics and color of whole chili pod and its components (i.e. seeds, pedicel, and placenta) of sun-dried chili during FIR roasting. The samples were dried at 7.76 μm (100 °C), 6.12 μm (200 °C), 5.056 μm (300 °C), and 4.30 μm (400 °C) by exposing them to FIR in a single layer and the drying kinetics were studied using the Midilli model. Further, the color variation during FIR roasting was studied.

RESULTS

FIR roasting of chili pods and their components (i.e. seeds, pedicel, and placenta) shows a falling rate drying period at each wavelength. The moisture content decreased with decreasing FIR wavelength. The ∆E values for pods, pedicel, and placenta were increased during FIR roasting. The Midilli model results in R² and root-mean-square error value ranges of 0.7563-1.000 and 5 × 10^-8 -0.1238 respectively for the current study. The Midilli model at 300 °C shows that the FIR has minor variation compared with other FIR temperatures.

CONCLUSION

FIR technology can be implemented to roast chili pods and their components (i.e. seeds, pedicel, and placenta) within a short period. Further, the application of FIR for roasting purposes desirably increases the color variation. The Midilli model can effectively describe the drying kinetics of the chili pods and their components during FIR roasting. © 2021 Society of Chemical Industry.

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.

Crushed Capsicum chacoense Hunz Fruits: A Food Native Resource of Paraguay with Antioxidant and Anthelmintic Activity

The nutritional composition and toxicity of native plants with food potential like Capsicum chacoense are important for the safe use of populations and could be used as a source for searching for new drug candidates. Infections produced by parasites such as helminths are a public health concern for many countries. The drugs used for treating these diseases are few, and the emergence of resistance is a risk. In this work, the nutritional composition, acute toxicity, antioxidant activity, and anthelmintic activity of crushed C. chacoense fruits were evaluated. The composition was analyzed by standard procedures. Antioxidant activity was evaluated using the ABTS radical and the total phenolic compound (TPC) tests. The toxicity was evaluated on Swiss albino mice by the single-DL50-dose procedure. The anthelmintic activity was tested against Eisenia foetida. The samples presented high levels of dietary fiber (47.05-49.19 g/100 g), proteins (14.43-15.60 g/100 g), and potassium (1708-1733 mg/100 g). In the samples, the absence of acute lethal effects in doses lower than 2000 mg/kg was observed. A rich composition of TPC (517.26-543.32 mg GAE/100 g sample), total carotenoids (125.72-239.57 mg/kg), β-carotene (3.29-5.60 mg/kg), and good TAC was observed (154-158 mM TEAC/g SMTC). The methanolic extracts at the doses tested (2.5 to 40 mg/mL) showed good anthelmintic activity. The presence of alkaloids was demonstrated in the methanolic extract, consistent with the levels of capsaicin (131.85 and 98.80 mg/100 g) and dihydrocapsaicin (80.75 and 63.68 mg/100 g), with significant statistical differences between samples (p < 0.05). These results show that through the chemical composition of this underutilized native resource and good fruit processing procedures, the C. chacoense fruits have a great nutraceutical potential of interest for the food and pharmaceutical industries.

Physico-Chemical Properties of Red Pepper (Capsicum annuum L.) as Influenced by Different Drying Methods and Temperatures

An experiment was carried out in the laboratories of the Department of Food Engineering, Department of Vegetable Science, and Department of Plantation Spices Medicinal and Aromatic crops, Bidhan Chandra Krishi Viswavidyalaya (BCKV), West Bengal, India. The work was performed during 2018–2019 and 2019–2020 with different drying methods including sun drying, solar drying and oven drying. In oven drying, different temperatures such as 50, 55, 60, 65, and 70 °C were considered. A randomized complete block design (RCBD) was designed with seven treatments and three replications. Experimental results were significantly varied among the treatments as influenced by different drying methods and temperatures. Minimum time taken (480 min) to reach safe moisture content was recorded in T7 (oven drying at 70 °C), whereas maximum values in color components such as L* value (24.55), a* value (32.14), b* value (20.53), and pungency score (7.85) were recorded in T6 (oven drying at 65 °C). However, the highest texture (1180.81) was observed in T1 (sun drying). Biochemical parameters were significantly varied among the treatments. The maximum amounts of ascorbic acid (56.06 mg/100 g) and oleoresin content (10.72) were found in T3 (oven drying at 50 °C), whereas minimum values of biochemical parameters were recorded by T1 (sun drying) and T2 (solar drying) methods, respectively. Mathematical relationships were found in different drying methods and temperatures. Models such as the Lewis, Page, Modified Page, and Henderson and Pabis models were selected to fit the data. Maximum R2 value (0.9835) was found in both the Page and Modified Page models with similar values of drying method and temperature at 65 °C. This value was the highest among all models in all drying temperatures. However, the lowest χ2, and RMSE values (0.000818 and 0.027261, respectively) were recorded with the Page model.

Capsicum SIZ1 contributes to ABA-induced SUMOylation in pepper

Abiotic and biotic stresses are the major factors limiting plant growth. Arabidopsis E3 SUMO ligase SIZ1 plays an essential role in plant stress tolerance. Herein, we identified a SIZ/PAIS-type protein in pepper (Capsicum annuum), namely CaSIZ1, which shares 60 % sequence identity with AtSIZ1. The stems and flowers of pepper had a relatively higher expression of CaSIZ1 than the fruits, leaves, and roots. ABA and NaCl treatments induced CaSIZ1. CaSIZ1 protein was localized in the nucleus and partially rescued the dwarf and ABA-sensitive phenotypes of Atsiz1-2, suggesting the functional replacement of CaSIZ1 with AtSIZ1. We found that CaSIZ1 interacted with CaABI5, and ABA promoted the accumulation of SUMO conjugates in pepper. CaSIZ1 knockdown did not only reduce ABA-induced SUMOylation, but also attenuated the salt tolerance of pepper. Overall, the results of this study suggest that CaSIZ1 has a significant role in ABA-induced SUMOylation and stress response.

Effect of the Soil and Ripening Stage in Capsicum chinense var. Jaguar on the Content of Carotenoids and Vitamins

The purpose of this work was to investigate the effect of the ripening stage and type of soil on the concentration of carotenoids and vitamins in Habanero pepper (Capsicum chinense Jacq.). Pepper plants were grown in two soils named according to the Mayan classification as: K’ankab lu’um (red soil) and Box lu’um (black soil). The results of two harvests at 320 and 334 PTD (post-transplant day) showed that the ripening stage exhibited a significant effect (p < 0.05) on the concentration of carotenoids and vitamins, while the effect of the soil type was negligible. The concentration of carotenoids decreases as the ripening process of the fruit takes place, with the highest concentration of lutein (49.47 ± 0.34 mg/100 g of dry mass), β-carotene (99.92 ± 0.69 mg/100 g of dry mass) and β-cryptoxanthin (20.93 ± 0.04 mg/100 g of dry mass) in the unripe peppers. The concentration of vitamins increases as the ripening process develops, with the highest concentration of Vitamin E (9.69 ± 0.02 mg/100 g of dry mass) and Vitamin C (119.44 ± 4.72 mg/100 g of dry mass) in the ripe peppers. This knowledge could be used to select the best ripening stage to harvest Habanero peppers according to the use of the pepper and to the needs of producers/company.

Identification of α-Glucosidase Inhibitors from Leaf Extract of Pepper (Capsicum spp.) through Metabolomic Analysis

Metabolomics and in vitro α-glucosidase inhibitory (AGI) activities of pepper leaves were used to identify bioactive compounds and select genotypes for the management of type 2 diabetes mellitus (T2DM). Targeted metabolite analysis using UPLC-DAD-QToF-MS was employed and identified compounds that belong to flavone and hydroxycinnamic acid derivatives from extracts of pepper leaves. A total of 21 metabolites were detected from 155 samples and identified based on MS fragmentations, retention time, UV absorbance, and previous reports. Apigenin-O-(malonyl) hexoside, luteolin-O-(malonyl) hexoside, and chrysoeriol-O-(malonyl) hexoside were identified for the first time from pepper leaves. Pepper genotypes showed a huge variation in their inhibitory activity against α-glucosidase enzyme(AGE) ranging from 17% to 79%. Genotype GP38 with inhibitory activity of 79% was found to be more potent than the positive control acarbose (70.8%.). Orthogonal partial least square (OPLS) analyses were conducted for the prediction of the AGI activities of pepper leaves based on their metabolite composition. Compounds that contributed the most to the bioactivity prediction model (VIP >1.5), showed a strong inhibitory potency. Caffeoyl-putrescine was found to show a stronger inhibitory potency (IC₅₀ = 145 µM) compared to acarbose (IC₅₀ = 197 µM). The chemometric procedure combined with high-throughput AGI screening was effective in selecting polyphenols of pepper leaf for T2DM management.

Discoloration investigations of freeze-dried carrot cylinders from physical structure and color-related chemical compositions

BACKGROUND

High carotenoid content always lead to a yellower/redder color in carrots, while a puzzling phenomenon still exists that freeze-dried carrots (FDC) have a higher carotenoid content but a lighter color compared with thermal-dried carrots. It seems that carotenoid is not the only main factor affecting sample color. Hence the discoloration characteristics of freeze-dried carrots were comprehensively analyzed from physical structure and color-related chemical composition profile.

RESULTS

Outcomes of low-field nuclear magnetic resonance and scanning electron microscopy showed that sublimation of immobilized water preserved the intact porous structure of FDC, which kept the volume shrinkage below 30% and led to less accumulations of color-related compositions. Besides, results of correlation and principal component analysis-X model proved that lutein and caffeic acid mainly affected a* value (r = 0.917) and b* value (r = 0.836) of FDC, respectively. Moreover, lipoxygenase indirectly affected sample color by degrading carotenoids, and the lutein content loss for fresh and blanching FDC was 41.56% and 47.14%, respectively.

CONCLUSIONS

The discoloration of FDC was significantly affected by both physical structure and color-related chemical compositions. © 2021 Society of Chemical Industry.

European Database of Carotenoid Levels in Foods. Factors Affecting Carotenoid Content

Many studies indicate that diets including carotenoid-rich foods have positive effects on human health. Some of these compounds are precursors of the essential nutrient vitamin A. The present work is aimed at implementing a database of carotenoid contents of foods available in the European market. Factors affecting carotenoid content were also discussed. Analytical data available in peer-reviewed scientific literature from 1990 to 2018 and obtained by HPLC/UHPLC were considered. The database includes foods classified according to the FoodEx2 system and will benefit compilers, nutritionists and other professionals in areas related to food and human health. The results show the importance of food characterization to ensure its intercomparability, as large variations in carotenoid levels are observed between species and among varieties/cultivars/landraces. This highlights the significance of integrating nutritional criteria into agricultural choices and of promoting biodiversity. The uncertainty quantification associated with the measurements of the carotenoid content was very rarely evaluated in the literature consulted. According to the EuroFIR data quality evaluation system for food composition tables, the total data quality index mean was 24 in 35, reflecting efforts by researchers in the analytical methods, and less resources in the sampling plan documentation.

Bioactive Compounds and Antioxidant Capacity of Valencian Pepper Landraces

Sweet pepper is one of the most important economic fruits with nutritional attributes. In this sense, the nutraceutical value of consumed products is a major concern nowadays so the content of some bioactive compounds and antioxidants (phenols, ascorbic acid, lycopene, carotenoids, chlorophylls, and antioxidant activity) was monitored in 18 sweet pepper landraces at two maturity stages (green and red). All the traits except chlorophylls significantly increased in red fruits (between 1.5- and 2.3-fold for phenols, ascorbic acid, and 2-2-diphenyl-1-picrylhydrazyl (DPPH) inhibition activity, 4.8-fold for carotenoid and 27.4-fold for lycopene content), which suggests that ripening is key for obtaining desired fruit quality. Among landraces, P-44 in green fruits is highlighted for its content in carotenoids, chlorophylls, phenols, and ascorbic acid, and P-46 for its antioxidant capacity and lycopene content. Upon maturity, P-48, P-44, and P-41 presented higher levels of phenols and lycopene, and P-39 of phenols, carotenoid, and DPPH. This work reflects a wide variability in the 18 pepper landraces at bioactive compounds concentration and in relation to fruit ripeness. The importance of traditional landraces in terms of organoleptic properties is emphasized as they are the main source of agricultural biodiversity today and could be helpful for breeders to develop new functional pepper varieties.

Affinity of class I and class III peroxidases for H2O2 in pepper leaves of different maturity

Paper deals with activities of Class III peroxidases (POX, EC 1.11.1.7) and Class I peroxidases (ascorbate peroxidase, APX, EC 1.11.1.11) as well as the Km of these enzymes for hydrogen peroxide (H2O2) in the pepper leaves of different maturity. The obtained results suggest that the youngest pepper leaves compared to more mature ones have different strategies for H2O2 removal. There was an increase in APX activity with leaf maturity, while POX activity had the opposite trend, and its lowest activity was observed in the oldest leaves. The accumulation of reducing substrates i.e., ascorbate and total phenols was in positive correlation with corresponding enzymes following leaf maturity. The comparison of POX and APX affinity for H2O2 in pepper leaves of different maturity and their relationship between these enzymes' activities were showed.

The effects of production methods on the color characteristics, capsaicinoid content and antioxidant capacity of pepper spices (C. annuum L.)

The effects of production methods for red pepper flakes (RPF) and traditional (TRI) and industrial (INI) isot spices were evaluated with respect to the carotenoid and capsaicinoid contents, extractable color (ASTA color), surface color parameters, nonenzymatic browning (NEB), and the DPPH free radical-scavenging capacity of fresh red Capsicum (FRC). The measured characteristics were significantly affected by the processing methods used. RPF exhibited the highest antioxidant activity and best color quality in terms of carotenoid content, which was the highest; ASTA value; surface color intensity; and NEB, which was the lowest. In contrast, INI-processing methods resulted in poor color quality, causing the maximum increase in NEB. The concentration of capsaicinoid increased at the end of TRI processing, whereas it decreased in the two other methods. These results suggest that the traditional production method for isots prevents excessive destruction of their color attributes and contributes to the desirable characteristic browning.

Antioxidant Profile of Pepper (Capsicum annuum L.) Fruits Containing Diverse Levels of Capsaicinoids

Capsicum is the genus where a number of species and varieties have pungent features due to the exclusive content of capsaicinoids such as capsaicin and dihydrocapsaicin. In this work, the main enzymatic and non-enzymatic systems in pepper fruits from four varieties with different pungent capacity have been investigated at two ripening stages. Thus, a sweet pepper variety (Melchor) from California-type fruits and three autochthonous Spanish varieties which have different pungency levels were used, including Piquillo, Padrón and Alegría riojana. The capsaicinoids contents were determined in the pericarp and placenta from fruits, showing that these phenyl-propanoids were mainly localized in placenta. The activity profiles of catalase, total and isoenzymatic superoxide dismutase (SOD), the enzymes of the ascorbate–glutathione cycle (AGC) and four NADP-dehydrogenases indicate that some interaction with capsaicinoid metabolism seems to occur. Among the results obtained on enzymatic antioxidants, the role of Fe-SOD and the glutathione reductase from the AGC is highlighted. Additionally, it was found that ascorbate and glutathione contents were higher in those pepper fruits which displayed the greater contents of capsaicinoids. Taken together, all these data indicate that antioxidants may contribute to preserve capsaicinoids metabolism to maintain their functionality in a framework where NADPH is perhaps playing an essential role.

Nitrogen Source Affects the Composition of Metabolites in Pepper (Capsicum annuum L.) and Regulates the Synthesis of Capsaicinoids through the GOGAT-GS Pathway

Phytochemical analyses of pepper fruit metabolites have been reported; however, much less is known about the influence of different forms of nitrogen (N), which is critical for plant growth and fruit quality formation. The "Longjiao No. 5" variety (Capsicum annuum L.) grown in Northwestern China was profiled using liquid chromatography-mass spectrometry (LC-MS) coupled with multivariate data analysis to explore the composition of different metabolites in pericarp and placenta, and to investigate the effect of three ammonium (NH4+)-to-nitrate (NO3-) ratios (0:100, 25:75, and 50:50). A total of 215 metabolites were obtained by qualitative analysis, where 31 metabolites were the major differential metabolite components of pepper fruits between placenta and pericarp, and 25 among N treatments. The addition of ammonium up-regulated carbohydrates, such as α-lactose and sucrose, as well as phenylalanine lyase (PAL) of placenta tissue. The supply of 25% NH4+-N and 75% NO3--N exhibited a relatively higher levels of ascorbic acid in pericarp and amino acids, capsaicin, and dihydrocapsaicin in placenta, and led to higher fruit weight among the ammonium-to-nitrate ratios. The expression and activities of glutamic acid synthetase (GOGAT) and glutamine synthetase (GS) that are involved in ammonium assimilation were affected by adjusting the ammonium-N proportion, and they were significantly positively correlated with capsaicin, dihydrocapsaicin contents, capsaicinoid synthetase (CS), as well as the relative expression levels of genes related to capsaicinoid biosynthesis, such as acyltransferase 3 (AT3) and acyl-ACP thioesterase (FatA).

Grown to be Blue-Antioxidant Properties and Health Effects of Colored Vegetables. Part II: Leafy, Fruit, and Other Vegetables

The current trend for substituting synthetic compounds with natural ones in the design and production of functional and healthy foods has increased the research interest about natural colorants. Although coloring agents from plant origin are already used in the food and beverage industry, the market and consumer demands for novel and diverse food products are increasing and new plant sources are explored. Fresh vegetables are considered a good source of such compounds, especially when considering the great color diversity that exists among the various species or even the cultivars within the same species. In the present review we aim to present the most common species of colored vegetables, focusing on leafy and fruit vegetables, as well as on vegetables where other plant parts are commercially used, with special attention to blue color. The compounds that are responsible for the uncommon colors will be also presented and their beneficial health effects and antioxidant properties will be unraveled.

Changes in volatile compounds, sugars and organic acids of different spices of peppers (Capsicum annuum L.) during storage

Changes in sugars, organic acids and volatile compounds (VC) of red pepper flakes (RPF), traditional (TRI), and industrial (INI) isot peppers were evaluated during one year storage at the room condition. The changes in the flavor components were significantly affected by the production methods and storage time. Glucose content decreased gradually along storage and reduced by about 21.23, 47.22 and 56.65% for TRI, INI and RPF, respectively. However, fructose decreased significantly only in RPF (11.29%). Citric and succinic acids exhibited slight changes, but malic acid showed an increasing trend, especially in RPF (4-fold). Most of the VC in all samples decreased or disappeared after storage. The major quantitative losses in these compounds were found in TRI during the first 3 months as 81.76%. The storage was found to be caused deterioration flavor properties in red pepper spices and revealed the importance of appropriate storage conditions.

Variability in the Phytochemical Contents and Free Radical-Scavenging Capacity of Capsicum annuum var. glabriusculum (Wild Piquin Chili)

The variability in the phytochemical concentrations of Capsicum annuum var. glabriusculum has not been extensively analyzed among wild populations and ecologic niches in its phylogeographic area. This study aimed to determine the variations in the phytochemical and antioxidant contents of the wild Piquin chili. The total flavonoid content of hydroalcoholic extracts (0.06 to 0.70 mg equivalent of quercetin per gram of dry weight (mg QE/g DW)), free radical-scavenging capacity for 2,2-diphenyl-1-picrylhydrazyl (DPPH^. ) radicals (0.55 to 8.55 mm TE/g DW), amount of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺ ) in aqueous extracts (18.13 to 107.6 mm TE/g DW) and pungency (21,760 to 88,476 Scoville heat units) were highly variable. By analyzing the spatial distribution using the first three principal components, correlations between the phytochemical content and the free radical-scavenging capacity (in both extracts) and flavonoid and phenolic contents (in the hydroalcoholic extract) were observed. Consistent with the statistical analysis, the spatial analysis showed intraregional differences in composition patterns, with an emphasis on central and coastal areas. Flavonoid contents, polyphenol contents and free radical-scavenging activity were the phytochemical components that mainly contributed to the diversity of the population.

Transcriptional Regulation of Ascorbic Acid During Fruit Ripening in Pepper (Capsicum annuum) Varieties with Low and High Antioxidants Content

Research on plant antioxidants, such as ascorbic acid (AsA) and polyphenols, is of increasing interest in plant science because of the health benefits and preventive role in chronic diseases of these natural compounds. Pepper (Capiscum annuum L.) is a major dietary source of antioxidants, especially AsA. Although considerable advance has been made, our understanding of AsA biosynthesis and its regulation in higher plants is not yet exhaustive. For instance, while it is accepted that AsA content in cells is regulated at different levels (e.g., transcriptional and post-transcriptional), their relative prominence is not fully understood. In this work, we identified and studied two pepper varieties with low and high levels of AsA to shed light on the transcriptional mechanisms that can account for the observed phenotypes. We quantified AsA and polyphenols in leaves and during fruit maturation, and concurrently, we analyzed the transcription of 14 genes involved in AsA biosynthesis, degradation, and recycling. The differential transcriptional analysis indicated that the higher expression of genes involved in AsA accumulation is a likely explanation for the observed differences in fruits. This was also supported by the identification of gene-metabolite relations, which deserve further investigation. Our results provide new insights into AsA differential accumulation in pepper varieties and highlight the phenotypic diversity in local germplasm, a knowledge that may ultimately contribute to the increased level of health-related phytochemicals.

Comparative Quantitative Study on Phytochemical Contents and Antioxidant Activities of Capsicum annuum L. and Capsicum frutescens L

The variabilities in the phytochemical contents and antioxidant activities of four varieties of two closely related cultivated Capsicum species, C. annuum and C. frutescens, were examined as an additional tool for establishing their phylogenetic relatedness and for breeding purposes. The methodology involved the use of ethanolic and aqueous extractions for the determination of the phytochemical and antioxidant properties. The phytochemical contents including total flavonoid, total phenol, and proanthocyanidins were evaluated spectrophotometrically while the antioxidant activities were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), nitric oxide (NO), and phosphomolybdenum assays. To point out the relationship among the varieties, a dendrogram based on the antioxidative phytochemical contents was constructed using the unweighted pair group method with arithmetic mean (UPMGA) cluster analysis. In all, aqueous extracts gave higher yield while ethanolic extracts showed higher phytochemical content across the varieties. Significant variations were observed among the varieties in relation to their phytochemical constituents and antioxidant activities. Dendrogram obtained from multivariate analysis distinguished the two Capsicum species. The first cluster contained only C. frutescens var. baccatum while the second cluster contained the three varieties of C. annuum species in subclusters, signifying the close genetic affinity among the three varieties. It also revealed that the four varieties are of a common progenitor. Information from this study gives additional evidence of chemotaxonomic significance and baseline data for effective selection of suitable parental genotypes in breeding for nutritional and pharmacological purposes.

Stable Carbon and Nitrogen Isotope Ratios of Red Bell Pepper Samples from Germany, The Netherlands, and Spain

Bell pepper is one of the most cultivated crops in the world. By means of δ¹³C and δ¹⁵N values (‰), red bell peppers from Germany, The Netherlands, and Spain could be distinguished from each other. German fruits cultivated under greenhouse conditions were extremely depleted in ¹³C with δ¹³C values for fatty acids of partly less than -50‰. The strong depletion in ¹³C was in accordance with the use of biomethane-derived CO₂ as growth regulator in the greenhouses. Seasonal variations in the δ¹³C values (‰) of German samples were tentatively assigned to varying CO₂ enrichment during the annual production cycle. δ¹³C values (‰) of Dutch samples also correlated with greenhouse production, whereas Spanish samples most likely originated from open field cultivation. Additionally, the use of color measurement as a tool for presorting the samples was investigated in order to slim the scattering ranges of δ¹³C and δ¹⁵N values (‰) for clearer differentiation.

CaMADS, a MADS-box transcription factor from pepper, plays an important role in the response to cold, salt, and osmotic stress

MADS-box family transcription factors play essential roles in the growth and development of plants, and some MADS-box genes have also been found to participate in the stress-response. At present, little information regarding stress-related MADS-box genes is available in pepper. We isolated a MADS-box transcription factor gene from Capsicum annuum, which we named CaMADS. CaMADS expression is induced by low and high temperature, salt, and osmotic stress, and also by abscisic acid (ABA), salicylic acid (SA), methyl-jasmonic acid (MeJA), and CaCl_2. To understand the function of CaMADS in the abiotic stress response, we generated pepper plants in which CaMADS expression was down-regulated using VIGS (Virus-induced Gene Silencing), and also transgenic Arabidopsis plants overexpressing CaMADS. We found that CaMADS-down-regulated seedlings were more seriously injured than WT after cold, NaCl, and mannitol treatment, and showed increased electrolyte leakage, malondialdehyde (MDA) levels, and lower chlorophyll content. CaMADS-overexpressing Arabidopsis plants were more tolerant to these stresses than WT, and showed significantly high survival rates and lower H₂O₂ and super oxide radical contents after cold treatment. CaMADS-overexpressing plants had higher germination rates and percentages of green cotyledons following NaCl and mannitol treatment. Root lengths and fresh weight in CaMADS-overexpressing plants were also significantly longer and higher, respectively, than in WT plants. Taken together, our results suggest that CaMADS functions as a positive stress-responsive transcription factor in the cold, salt, and osmotic stress signaling pathways.

Free Radical-Scavenging Capacities, Phenolics and Capsaicinoids in Wild Piquin Chili (Capsicum annuum var. Glabriusculum)

The total phenolic compounds content, free radical-scavenging capacity and capsaicinoid content in populations of wild Piquin chili (C. annuum) were studied. Aqueous and hydroalcoholic extracts from nine ecotypes were evaluated. High contents of phenolic compounds and free radical-scavenging capacities were observed for both extracts; however, the values that were found for the hydroalcoholic phase were substantially higher. LC-MS analysis allowed for the detection of 32 compounds, where apigenin-8-C-glucoside followed by vanillic acid 1-O-β-o-glucopyranosylester (Isomer I or II) and 7-ethoxy-4-methylcoumarin were the most widely distributed; they were found in more than 89% of the ecotypes. The diversity of identified phenolic compounds was different among ecotypes, allowing them to be distinguished by chemical diversity, free radical-scavenging capacities and heat Scoville units. The total capsaicinoid content was higher in Population I (23.5 mg/g DW) than in Populations II and III, which had contents of 15.3 and 10.7 mg/g DW, respectively. This variability could lead to phytochemical exploitation and the conservation of the natural populations of wild chili.

Evaluation of capsaicinoid profile and antioxidant properties in dried Korean red pepper (Capsicum annuum L.) as affected by variable dose rates of electron beam and gamma ray irradiation

The application of food irradiation is based on the parameters including energy (MeV), dose rate (kGy/s or kGy/h), and absorbed dose (kGy). Red pepper powders were treated with different dose rates of 1, and 5 kGy/s electron beam (EB) as well as 1.8 and 9 kGy/h gamma ray (GR) in separate experiments. Constant absorbed dose (3 kGy) was maintained to observe whether different dose rates affect the product quality. Total and individual capsaicinoids increased at low EB and GR dose rates. Vitamin C content decreased at all dose rates, except at low GR dose rate, where no significant difference was observed. Low EB dose rate led to a marked increase (21%) in the total phenolics than high dose rate (13%). In contrast, high GR dose rate increased the total phenolics than low dose rate. Maximum antioxidants (1.36 mg TE/mL) were observed at high EB dose rate, although low dose rate also increased the antioxidant activity. Results indicated that different dose rates delivering the same absorbed dose had significant impact on the product quality and that the efficacy of absorbed dose is dependent on applied dose rates. In other words, a constant absorbed dose applied to the product is influenced by dose rate of the irradiation treatment.

The genus Capsicum: a phytochemical review of bioactive secondary metabolites

The Capsicum genus is one of the most popular plants consumed and cultivated worldwide, containing approximately 50 000 varieties of pepper. Due to its wide biodiversity, the chemical composition within the genus also presents a great variability. Its major applications are in food and pharmacological industry, as pepper presents a chemical composition rich in capsaicinoids, carotenoids, flavonoids and volatile compounds which is attributed to the ability of the fruit to remove insipidity, produce aromas and act against oxidative diseases. Due the existence of several cultivars there is a huge intraspecific chemical variability within each species, which can be considered as an obstacle when selecting and cultivating a species to be applied as a natural product source for a specific objective. The usage of pepper-based products in different industrial areas requires pre-established ranges of chemical compounds, such as capsaicinoids, which in high concentration are toxic when consumed by humans. Applying a pepper with a chemical profile closely related to the concentration that is required after industrial processing can improve efficacy and effectiveness of the process. An insight into the chemical characteristics of major secondary bioactive compounds within Capsicum, the factors that affect their concentration and their chemosystematic implication are reported and discussed.

Occurrence of variable levels of health-promoting fruit compounds in horn-shaped Italian sweet pepper varieties assessed by a comprehensive approach

BACKGROUND

Cultivated pepper is a rich source of diverse bioactive compounds with potential properties related to the prevention of major degenerative and proliferative diseases. In the present study, 15 sweet pepper varieties, highly appreciated on the Italian market, were assessed for variation in the content of ascorbic acid, isoprenoids and flavonoids, as well as morpho-agronomic performances and molecular diversity.

RESULTS

The collection under study showed a wide variability for all traits considered. Traditional cultivars, although less productive, were characterized by a high content of β-carotene and ascorbic acid, reaching maximum concentrations of 230.5 mg kg^-1 fresh weight (fw) and 2750 mg kg^-1 fw, respectively. Strong correlations were demonstrated between neoxanthin and luteolins. Fruit weight was positively correlated with α-tocopherol content and negatively correlated with luteolins content. The genotyping by sequencing platform allowed the identification of 1833 single nucleotide polymorphism, which better defined the relationships among cultivars, based on provenance and improvement rate.

CONCLUSIONS

The present study provides an overview of the variability in the expression of fruit nutritional traits in a collection of horn-shaped pepper cultivars, integrating agronomic and molecular data. The impact for breeding and consumers is discussed. © 2017 Society of Chemical Industry.