Characterization of 12 Capsicum varieties by evaluation of their carotenoid profile and pungency determination

Apocarotenoids profiling in different Capsicum species

The present study report on the application of an on line supercritical fluid extraction-supercritical fluid chromatography-triple quadrupole/mass spectrometry methodology to the first apocarotenoids profiling of seventeen different chilli peppers cultivars belonging to Capsicum annuum, Capsicum baccatum and Capsicum chinense species. A total of 19 free apocarotenoids and 8 apocarotenoids fatty acid esters were identified; β-Apo-8'-carotenal and Apo-8'-zeaxanthinal were also quantified and the β-Apo-8'-carotenal occurrence was in the percentage ranges relative to β-carotene of 0.03-3.87%. PCA was performed as a multivariate display method on the quantified carotenoids and apocarotenoids, in order to visualize the data structure. Moreover, different ε-apoluteinals and 4-oxo-apo-β-carotenals were detected in Capsicum species also for the first time and, to the best of authors knowledge, in any food matrix.

Evaluation of the physiochemical and aromatic qualities of pickled Chinese pepper (Paojiao) and their influence on consumer acceptability by using targeted and untargeted multivariate approaches

Paojiao, which is traditionally pickled Chinese chili peppers (Capsicum frutescens Linn.), possesses unique flavors. This study was conducted to investigate the flavor, mouthfeel, and consumer acceptability of Paojiao. The quality of six homemade and two industrial Paojiao samples were evaluated by integrating untargeted (to fingerprint volatile fraction) and targeted (to analyze free amino acids or FAAs, capsaicinoids, and texture) approaches. Furthermore, multivariate data analysis (MVDA) was applied to identify the quality characteristics that drive the consumer acceptability for Paojiao. As for the targeted quality, hardness (1.30-10.52 N) and capsaicin (2.22-3.84 mg/g) varied with different samples. The main taste-active FAAs in Paojiao were detected. A total of 127 volatiles were observed, and esters were the major components. Based on sensory analysis, the homemade samples received higher acceptability than the industrial samples. MVDA demonstrated that some key volatiles, taste-active FAAs, and chewiness were the discriminant quality attributes affecting consumer acceptability.

DNA methylation is involved in the regulation of pepper fruit ripening and interacts with phytohormones

There is growing evidence to suggest that epigenetic tags, especially DNA methylation, are critical regulators of fruit ripening. To examine whether this is the case in sweet pepper (Capsicum annuum) we conducted experiments at the transcriptional, epigenetic, and physiological levels. McrBC PCR, bisulfite sequencing, and real-time PCR demonstrated that DNA hypomethylation occurred in the upstream region of the transcription start site of some genes related to pepper ripening at the turning stage, which may be attributed to up-regulation of CaDML2-like and down-regulation of CaMET1-like1, CaMET1-like2, CaCMT2-like, and CaCMT4-like. Silencing of CaMET1-like1 by virus-induced gene silencing led to DNA hypomethylation, increased content of soluble solids, and accumulation of carotenoids in the fruit, which was accompanied by changes in expression of genes involved in capsanthin/capsorubin biosynthesis, cell wall degradation, and phytohormone metabolism and signaling. Endogenous ABA increased during fruit ripening, whereas endogenous IAA showed an opposite trend. No ethylene signal was detected during ripening. DNA hypomethylation repressed the expression of auxin and gibberellin biosynthesis genes as well as cytokinin degradation genes, but induced the expression of ABA biosynthesis genes. In mature-green pericarp, exogenous ABA induced expression of CaDML2-like but repressed that of CaCMT4-like. IAA treatment promoted the transcription of CaMET1-like1 and CaCMT3-like. Ethephon significantly up-regulated the expression of CaDML2-like. Treatment with GA3 and 6-BA showed indistinct effects on DNA methylation at the transcriptional level. On the basis of the results, a model is proposed that suggests a high likelihood of a role for DNA methylation in the regulation of ripening in the non-climacteric pepper fruit.

Content of Vitamin C, Phenols and Carotenoids Extracted from Capsicum annuum with Antioxidant, Antimicrobial and Coloring Effects

BACKGROUND AND OBJECTIVE

Capsicum annuum is considered a good source of various natural compounds. The current study aimed to assess the vitamin C and total phenolic and carotenoid contents in C. annuum using standard methods.

MATERIALS AND METHODS

Microwave and Soxhlet extraction by using water and acetone were used to extract vitamin C and phenols. Saponification extraction was used to extract carotenoids. The antioxidant activities of each extract were assessed using a DPPH assay. The Minimum Inhibitory Concentration and Minimum Bactericidal Concentration (MIC and MBC) against Escherichia coli and Staphylococcus aureus were determined using the broth microdilution method. The coloring capacity for the acetone extract was evaluated and determined using glass wool fiber at different concentrations and then used in the formulation of multivitamin hard candy.

RESULTS

The acetone extract showed the highest phenol and vitamin C content (1.03±0.02 and 9.7±1.3 mg mL-1, respectively), antioxidant activity (67.12±3.8 mg mL-1) and MIC and MBC of 0.96 and 1.88 mg mL-1 against E. coli and 3.75 and 7.5 mg mL-1 against S. aureus. It also showed an intense orange shade on wool fiber and on the prepared multivitamin candy at concentrations of 6 and 0.5% (w/w), respectively. Saponifications of the acetone extract yield (23.49±0.13 μg g-1) of carotenoids.

CONCLUSION

The prepared acetone extract of C. annuum stands as a potential pharmaceutical additive, which can be used as coloring and preservative agents in the formulation of kids multi-vitamin candy.

Effect of gamma radiation and storage at 4°C on the inactivation of Listeria monocytogenes, Escherichia coli and Salmonella enterica Typhimurium in Legon-18 pepper (Capsicum annuum) powder

Objectives

Spices are low moisture foods which have been known to be contaminated with various pathogens and sun-dried Legon-18 pepper powder is not left out. Due to its contamination with various pathogens, a study was conducted to determine the effects of gamma irradiation on the decontamination of Legon-18 pepper powder and on some quality parameters.

Methods

Samples were obtained from a local farmer from the Eastern Region of Ghana. Sterility tests were carried out. The samples were inoculated with known cfu/ml of Escherichia coli, Listeria monocytogenes and Salmonella enterica Typhimurium. Samples were irradiated at 1, 2, 4, and 5 kilogray (kGy). Zero kilogray served as control (unirradiated). All samples were stored at 4oC for 60 days. Enumeration of the various pathogens was done in appropriate media. Some quality parameters were determined after irradiating unsterile samples at 5 kGy and 0 kGy served as control. Capsaicinoids and carotenoids were quantified using a high performance liquid chromatography. The samples were stored at 4oC for 8 weeks.

Results

A dose-dependent effect on the inactivation of the pathogens was observed (P < 0.05). Storage time affected the inactivation of the pathogens as well (P < 0.05). Complete inactivation of the pathogens was observed at 5 kGy at day 0. Capsaicin, dihydrocapsaicin and total capsaicinoid content of the samples irradiated at 5 kGy increased at 23.64%, 14.7 % and 20.95% respectively as compared with the contents of the unirradiated samples. A gamma irradiation dose of 5 kGy caused losses of 8.11%, 8.67% and 26.54% in capsanthin, beta carotene and beta cryptoxanthin respectively. Quality parameters measured reduced with storage (P < 0.05).

Conclusions

Gamma irradiation inactivated pathogens at 5 kGy. Lower doses used during the study could inactivate the pathogens but with time. All quality parameters and carotenoids quantified were affected by gamma irradiation and storage period (P < 0.05).

Optimizing and Comparing Ultrasound- and Microwave-Assisted Extraction Methods Applied to the Extraction of Antioxidant Capsinoids in Peppers

Capsinoids are very similar antioxidant compounds to capsaicinoids, but less irritating, non-pungent and more palatable, and can thus be used in greater concentrations for food applications. To date, three capsinoids (capsiate, dihydrocapsiate, and nordihydrocapsiate) have been isolated from the pepper fruits. Due to its substantial commercial importance, it would be convenient to determine which pepper varieties have a richer content. Ultrasound- (UAE) and microwave- (MAE) assisted extraction have been implemented and analyzed using multivariate statistical methods. Firstly, different solvents were tested individually. The three best solvents were used in a set mixture design, where 42% methanol and 58% ethyl acetate were determined as the optimum combination for UAE, and 100% methanol for MAE. Subsequently, a Box–Behnken experimental design with four variables for both UAE and MAE (time, temperature, pH and sample mass:solvent volume “ratio”) was performed. The sample mass:solvent volume was the most influential variable in UAE; while for MAE no variable was any more influential than the others. Finally, both optimized extraction methods were successfully applied to different varieties of peppers. Besides, to demonstrate the efficiency of both extraction methods, a recovery study was performed. The results prove the potential of both techniques as highly adequate methods for the extraction of capsinoids from peppers.

Carotenoids of Capsicum Fruits: Pigment Profile and Health-Promoting Functional Attributes

Pepper of the Capsicum species is a common ingredient in various food preparations by different cultures worldwide. The Capsicum is recognised by its five main domesticated species, namely Capsicum annuum, C. baccatum, C. chinense, C. frutescens and C. pubescens. The genetic diversity in Capsicum offers fruits in wide ranges of morphology and carotenoid profile. Carotenoids enhance the value of pepper from a nutritional standpoint, despite being commonly prized for the pharmacologically active pungent capsaicinoids. Carotenoids of pepper comprise mainly of the unique, powerful and highly stable capsanthin and capsoroubin, together with β-carotene, β-cryptoxanthin, lutein, zeaxanthin, antheraxanthin and violaxanthin. These carotenoids are present at diverse profile and varying levels, biosynthetically connected to the fruit maturity stages. This review describes the health-promoting functional attributes of the carotenoids that are mainly associated with their excellent role as lipophilic antioxidants. Capsicum as a great source of carotenoids is discussed in the aspects of main domesticated species, biosynthesis, pigment profile, antioxidant activity and safety. Findings from a number of in vitro, in vivo and clinical studies provided appreciable evidence on the protective effects of pepper’s carotenoids against degenerative diseases. Hence, pepper with its functional carotenoids might be recommended in health-promoting and disease preventing strategies.

Carotenoid biosynthesis and sequestration in red chilli pepper fruit and its impact on colour intensity traits

The exploitation of diverse natural variation has been a key progenitor of crop breeding over the last decade. However, commercial practice is now turning to the use of accessions with less extreme phenotypes as genetic donors. In the present study, the carotenoid formation in a red-fruited discovery panel of Capsicum annuum (chilli pepper) has been characterized. The data indicated that colour intensity correlated with the amount of capsanthin and its esters, along with transcript levels of the 1-deoxy-d-xylulose 5-phosphate synthase (DXS) and phytoene synthase-1 (PSY-1) genes. Quantification of carotenoids through development and ripening suggested the presence of separate biosynthesis and accumulation phases. Subplastid fractionation demonstrated the differential sequestration of pigments in high- and low-intensity lines and revealed the PSY protein to be most active in the membrane fractions when abundance was highest in the fibril fractions. Carotenoid accumulation was associated with the esterification of xanthophylls, expression of a putative carotenoid acyl transferase, and increased fibril content within the plastid. Interrogation of TEM images and carotenoid analysis of subplastid fractions suggest that the plastoglobuli are likely to be the progenitor of the characteristic fibrils found in pepper fruit. Collectively, these data provide an insight into the underpinning molecular, biochemical, and cellular mechanisms associated with the synthesis and sequestration of carotenoids in chromoplast-containing fruits, in addition to providing potential tools and resources for the breeding of high red colour intensity pepper varieties.

Progression of the Total and Individual Capsaicinoids Content in the Fruits of Three Different Cultivars of Capsicum chinense Jacq

The evolution of individual and total capsaicinoids content in three pepper varieties of Capsicum chinense Jacq. (‘Bode’ (B), ‘Habanero’ (H), and ‘Habanero Roxo’ (Hr)) during fruit ripening was studied. The five major capsaicinoids (nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin) were extracted using ultrasound-assisted extraction and the extracts were analysed by ultra-performance liquid chromatography with fluorescence detection (UHPLC-Fl). The plants were grown in a glasshouse and sampled every 7 days until over-ripening. As expected, the results indicated that the total capsaicinoids content increases during the ripening of pepper fruits. The maximum contents of capsaicinoids were reached at different fruit development stages depending on the cultivar. The ‘Habanero Roxo’ pepper presented the greatest total capsaicinoids content (3.86 mg g−1 fresh weigh, F.W.), followed by the ‘Habanero’ pepper (1.33 mg g−1 F.W.) and ‘Bode’ pepper (1.00 mg g−1 F.W.). In all the samples, capsaicin represented more than 80% of the total capsaicinoids content. Due to the high variability observed in the evolution of capsaicinoids content over the ripening process, this work intends to contribute to the existing knowledge on this aspect in relation to the quality of peppers.

Large-scale profiling of carotenoids by using non aqueous reversed phase liquid chromatography - photodiode array detection - triple quadrupole linear ion trap mass spectrometry: Application to some varieties of sweet pepper (Capsicum annuum L.)

Analysis of carotenoids is very complex and demanding in terms of both separation and detection. In this article, an analytical strategy relying on high-performance liquid chromatography-photodiode array detection-tandem mass spectrometry (HPLC-PAD-MS/MS) is presented for the large-scale screening of these phytochemicals. Separation was realized by means of Non-Aqueous Reversed Phase (NARP) chromatography on a triacontyl stationary phase kept at subambient temperature, using a mobile phase compatible with atmospheric pressure chemical ionization (APCI). The standards of 14 analytes were used to optimize the method and to predict the chromatographic behaviour of untargeted carotenoids. MS and MS/MS data, obtained during Information Dependent Acquisition (IDA) experiments, were utilized to set up a sensitive HPLC- selected reaction monitoring (SRM) method. Relative abundance between SRM ion currents (ion ratio) allowed the MS distinction of structural isomers (for example, bicyclic, monocyclic and acyclic isomers), while the identification of geometrical isomers was based on Q_ratio and fine structure, as calculated from UV-vis spectra. The comparison of LC-PAD- SRM chromatograms, acquired after applying two different extraction procedures (matrix solid-phase dispersion and overnight cold saponification), allowed verifying that sweet peppers are a good source of xanthophylls, prevalently occurring as esterified forms. The overall strategy could identify more than 40 carotenoids in some sweet pepper varieties (Jolly, horn and sweet chili pepper) available on the Italian and European food market.

Regional Pungency Degree in China and Its Correlation with Typical Climate Factors

Chili is an indispensable condiment in Chinese dishes. Due to regional environmental and cultural differences, there are certain differences in the regional food spicy degree. This study analyzed the pungency degree of dishes in 21 regions of China and created a pungency degree map using experiments and statistics. Seven typical climatic factors were selected, such as temperature and humidity, to analyze the most influential climatic factor on pungency degree through multiple regression methods. This study sampled 300 dishes of 12 cities in three typical provinces (Sichuan, Hubei, and Zhejiang) and found out the SHU (pungency degree in Scoville Heat Units) of dishes to supplement the study. The results suggest that Guizhou cuisine is the most pungent, where the proportion of dishes with chili is more than 50%. In the pungency degree map of the 21 Chinese regions, southwest China has cuisine that is strongly pungent, and the next pungent cuisine area includes the middle reaches of the Yangtze River, Shanxi, and Ningxia. The cold area in northeast China, including Qinghai and Beijing, is the area of intermediate pungent cuisine. Central and eastern parts of China belong to the light pungent cuisine area. The field sampling of 12 cities also confirmed that the pungency degree of regions is Sichuan > Hubei > Zhejiang. The multiple regression analysis results suggest that the most influential climatic factor is the average sunshine duration which has negative correlation with pungency degree. PRACTICAL APPLICATION: Environment correlative dietology is an emerging and important discipline in China. This research has helped us to enrich our data on chili dishes and expand our geo-environmental food database. In terms of the flavor of the dishes, objective data were used instead of the former subjective comments for quantitative analysis. Since ancient times, there has been a traditional saying of spicy dehumidification and perspiration. This study uses mathematical statistical analysis methods to innovatively analyze the correlation between regional chili taste and geographical environment climate. These are all conducive to the establishment of scientific and healthy food flavor models.

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.

Significance of Genetic, Environmental, and Pre- and Postharvest Factors Affecting Carotenoid Contents in Crops: A Review

Carotenoids are a diverse group of tetraterpenoid pigments that play indispensable roles in plants and animals. The biosynthesis of carotenoids in plants is strictly regulated at the transcriptional and post-transcriptional levels in accordance with inherited genetic signals and developmental requirements and in response to external environmental stimulants. The alteration in the biosynthesis of carotenoids under the influence of external environmental stimulants, such as high light, drought, salinity, and chilling stresses, has been shown to significantly influence the nutritional value of crop plants. In addition to these stimulants, several pre- and postharvesting cultivation practices significantly influence carotenoid compositions and contents. Thus, this review discusses how various environmental stimulants and pre- and postharvesting factors can be positively modulated for the enhanced biosynthesis and accumulation of carotenoids in the edible parts of crop plants, such as the leaves, roots, tubers, flowers, fruit, and seeds. In addition, future research directions in this context are identified.

Flavor characterization of native Peruvian chili peppers through integrated aroma fingerprinting and pungency profiling

A broad range of Peruvian chili peppers are available but not properly characterized. To increase the insight into their flavor compounds, a head space GC-MS fingerprinting (volatiles) and an HPLC-based profiling approach (pungency) was implemented to characterize twenty landraces (Capsicum annuum, C. baccatum and C. chinense). The data obtained was analyzed with powerful chemometric approaches to identify unique flavor compounds for each of the species and for each of the landraces within a specific species. The pungency profile and volatiles such as esters, terpenes and norcarotenoids distinguish Cerezo triangular (4) (C. annuum). Mainly esters provoked the separation between Chico (42), Cacho de cabra rojo (323), Amarillo de Chachapoyas (318) (C. baccatum), Arnaucho (60) and Miscucho amarillo (69) (C. chinense). This study demonstrates the potential of the integrated fingerprinting, profiling and a chemometric approach to extensively understand the unique flavor compounds in Peruvian chili peppers.

Characterization of the pigment fraction in sweet bell peppers (Capsicum annuum L.) harvested at green and overripe yellow and red stages by offline multidimensional convergence chromatography/liquid chromatography-mass spectrometry

Offline multidimensional supercritical fluid chromatography combined with reversed-phase liquid chromatography was employed for the carotenoid and chlorophyll characterization in different sweet bell peppers (Capsicum annuum L.) for the first time. The first dimension consisted of an Acquity HSS C18 SB (100 × 3 mm id, 1.8 μm particles) column operated with a supercritical mobile phase in an ultra-performance convergence chromatography system, whereas the second dimension was performed in reversed-phase mode with a C30 (250 × 4.6 mm id, 3.0 μm particles) stationary phase combined with photodiode array and mass spectrometry detection. This approach allowed the determination of 115 different compounds belonging to chlorophylls, free xanthophylls, free carotenes, xanthophyll monoesters, and xanthophyll diesters, and proved to be a significant improvement in the pigments determination compared to the conventional one-dimensional liquid chromatography approach so far applied to the carotenoid analysis in the studied species. Moreover, the present study also aimed to investigate and to compare the carotenoid stability and composition in overripe yellow and red bell peppers collected directly from the plant, thus also evaluating whether biochemical changes are linked to carotenoid degradation in the nonclimacteric investigated fruits, for the first time.

Brazilian Capsicum peppers: capsaicinoid content and antioxidant activity

BACKGROUND

Capsicum peppers are known as a source of capsaicinoids, phenolic compounds and antioxidants. Brazilian Capsicum peppers are important spices used in foods worldwide. However, little information is available on the chemical composition and antioxidant activity of these peppers.

RESULTS

Capsaicin, dihydrocapsaicin, total phenolic compounds and antioxidant activity were investigated in extracts of three Brazilian peppers: Capsicum frutescens, C. chinense and C. baccatum var. pendulum, in two different harvest years and at two ripening stages. The bioactive compound content was dependent on harvest year, and changes in the concentration profiles were found for capsaicin. Mature fruits of C. chinense harvested in the first year had the highest capsaicin concentration (2.04 mg g^-1 fresh pepper), and mature fruits of C. frutescens harvested in the same first year had the highest dihydrocapsaicin content (0.95 mg g^-1 fresh pepper). Mature fruits of C. frutescens harvested in the first year showed the major total phenolic compound content (2.46 mg g^-1 fresh pepper). The total phenolic compound content was directly related to antioxidant activity.

CONCLUSION

Our results suggest that phenolic compounds significantly contribute to the antioxidant activity of the investigated peppers. Also, these data add valued novel information that enhances current knowledge of Brazilian pepper fruits. © 2017 Society of Chemical Industry.

Influence of Fruit Ripening on Color, Organic Acid Contents, Capsaicinoids, Aroma Compounds, and Antioxidant Capacity of Shimatogarashi (Capsicum frutescens)

Shimatogarashi (Capsicum frutescens) is a typical chili pepper domesticated in southern Japan. Important traits of Shimatogarashi peppers, such as color; proportion of organic acids, capsaicinoids, and aromatic compounds; and antioxidant activity in three stages of maturity (green (immature), orange (turning), and red (mature) stages) were characterized. The results indicated that the concentration of organic acids, including ascorbic, citric, and malic acid, increased during ripening. In addition, the amount of capsaicinoids, which are responsible for the pungent taste of chili peppers, increased as the fruit matured to the orange and red stages. The volatile compound profile of Shimatogarashi was dominated by the presence of esters, which mainly contributed to fruity notes. The total amount of volatile compounds analyzed by gas chromatography-headspace solid-phase microextraction (GC-HS-SPME), especially esters, decreased as the fruit changed in color from green to red. This was in contrast to the amount of terpenoids, especially limonene, which increased at the red stage, denoting a change in flavor from fruity to a more citrus-like aroma. Based on the total phenolic content (TPC), the oxygen radical absorbance capacity (ORAC) and the diphenylpicrylhydrazyl (DPPH) free radical method, the antioxidant capacity of Shimatogarashi showed an increase at the mature red stage. However, while the red stage showed higher pungency and antioxidant capacity as well as an attractive color, the results of aromatic compound analysis revealed that the immature green stage had the advantages of having pleasant fruity smell, making it suitable for use in condiments.

Untargeted Metabolomic Analysis of Capsicum spp. by GC-MS

INTRODUCTION

In order to conserve the biodiversity of Capsicum species and find genotypes with potential to be utilised commercially, Embrapa Clima Temperado maintains an active germplasm collection (AGC) that requires characterisation, enabling genotype selection and support for breeding programmes.

OBJECTIVE

The objective of this study was to characterise pepper accessions from the Embrapa Clima Temperado AGC and differentiate species based on their metabolic profile using an untargeted metabolomics approach.

MATERIAL AND METHODS

Cold (-20°C) methanol extraction residue of freeze-dried fruit samples was partitioned into water/methanol (A) and chloroform (B) fractions. The polar fraction (A) was derivatised and both fractions (A and B) were analysed by gas chromatography coupled to mass spectrometry (GC-MS). Data from each fraction was analysed using a multivariate principal component analysis (PCA) with XCMS software.

RESULTS

Amino acids, sugars, organic acids, capsaicinoids, and hydrocarbons were identified. Outlying accessions including P116 (C. chinense), P46, and P76 (C. annuum) were observed in a PCA plot mainly due to their high sucrose and fructose contents. PCA also indicated a separation of P221 (C. annuum) and P200 (C. chinense), because of their high dihydrocapsaicin content.

CONCLUSIONS

Although the metabolic profiling did not allow for grouping by species, it permitted the simultaneous identification and quantification of several compounds complementing and expanding the metabolic database of the studied Capsicum spp. in the AGC. Copyright © 2017 John Wiley & Sons, Ltd.

Xanthophyll esters are found in human colostrum

SCOPE

Carotenoids in human milk are associated with other lipid counterparts in several metabolic processes. One interesting association that has not been demonstrated to date is the presence of xanthophyll esters. Colostrum and mature milk samples were analyzed to determine the occurrence of xanthophyll esters and identify the compounds. Thus, the association of the amounts of these compounds with lactation and whether they are significant contributors to the carotenoid profile of human milk was assessed.

METHODS AND RESULTS

Pre-term and term delivering mothers were included in the study to donate colostrum at 3-5 days postpartum and mature milk at 15 days postpartum. Carotenoids extracts were subjected to a clean-up procedure to remove the triacylglycerol fraction and then analyzed by HPLC-MSⁿ . Identification of xanthophyll esters was achieved by considering their chromatographic behaviour, UV-visible characteristics and MSⁿ features.

CONCLUSION

Xanthophyll esters are significant contributors to the carotenoid profile in the colostrum, while mature milk does not contain these compounds. Therefore, fatty acid acylation to xanthophylls is activated during the accumulation of carotenoids in the human mammary gland. The sharp decline in the amount of xanthophyll esters in mature milk indicates that the lipophilic components are those recently incorporated in the mammary epithelium.

Fast analysis of capsaicinoids in Naga Jolokia extracts (Capsicum chinense) by high-performance liquid chromatography using fused core columns

A rapid high-performance liquid chromatography method with a C18 reverse-phase fused-core column has been developed for the determination and quantification of the main capsaicinoids (nornordihydrocapsaicin, nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin and homodihydrocapsaicin) present in Naga Jolokia peppers. A fused-core Kinetex™ C18 column (50×2.1mm i.d.; 2.6μm) was used for the analysis. The chromatographic separation was obtained with a gradient method in which the mobile phase was water (0.1% acetic acid) as solvent A and acetonitrile (0.1% acetic acid) as solvent B. The separation of all compounds was achieved in less than 3min with a total analysis time (sample-to-sample) of 10min. The robustness of the method was evaluated. The method showed excellent repeatability and intermediate precision expressed as coefficient of variance of less than 2%. The developed method was employed for the quantification of the major capsaicinoids present in different peppers and commercial products containing chilli peppers.

Ontogenetic Variation of Individual and Total Capsaicinoids in Malagueta Peppers (Capsicum frutescens) during Fruit Maturation

The ontogenetic variation of total and individual capsaicinoids (nordihydrocapsaicin (n-DHC), capsaicin (C), dihydrocapsaicin (DHC), homocapsaicin (h-C) and homodihydrocapsaicin (h-DHC)) present in Malagueta pepper (Capsicum frutescens) during fruit ripening has been studied. Malagueta peppers were grown in a greenhouse under controlled temperature and humidity conditions. Capsaicinoids were extracted using ultrasound-assisted extraction (UAE) and the extracts were analyzed by ultra-performance liquid chromatography (UHPLC) with fluorescence detection. A significant increase in the total content of capsaicinoids was observed in the early days (between 12 and 33). Between day 33 and 40 there was a slight reduction in the total capsaicinoid content (3.3% decrease). C was the major capsaicinoid, followed by DHC, n-DHC, h-C and h-DHC. By considering the evolution of standardized values of the capsaicinoids it was verified that n-DHC, DHC and h-DHC (dihydrocapsaicin-like capsaicinoids) present a similar behavior pattern, while h-C and C (capsaicin-like capsaicinoids) show different evolution patterns.

Carotenoid esters in foods - A review and practical directions on analysis and occurrence

Carotenoids are naturally found in both free form and esterified with fatty acids in most fruits and some vegetables; however, up to now the great majority of studies presents data on carotenoid composition only after saponification. The reasons for this approach are that a single xanthophyll can be esterified with several different fatty acids, generating a great number of different compounds with similar chemical and structural characteristics, thus, increasing the complexity of analysis compared to the respective saponified extract. This means that since UV/Vis spectrum does not change due to esterification, differentiation between free and acylated xanthophylls is dependent at least on elution order and mass spectrometry (MS) features. The presence of interfering compounds, especially triacylglycerides (TAGs), in the non-saponified extract of carotenoids can also impair carotenoid ester analyses by MS due to high background noise and ionization suppression since TAGs can be present in much higher concentrations than the carotenoid esters. This leads to the need of development of new and effective clean-up procedures to remove the potential interferents. In addition, only few standards of xanthophyll esters are commercially available, making identification and quantification of such compounds even more difficult. Xanthophyll esterification may also alter some properties of these compounds, including solubility, thermostability and bioavailability. Considering that commonly consumed foods are dietary sources of xanthophyll esters and that it is the actual form of ingestion of such compounds, an increasing interest on the native carotenoid composition of foods is observed nowadays. This review presents a compilation of the current available information about xanthophyll ester analyses and occurrence and a practical guide for extraction, pre-chromatographic procedures, separation and identification by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Comparative Analysis of Fruit Metabolites and Pungency Candidate Genes Expression between Bhut Jolokia and Other Capsicum Species

Bhut jolokia, commonly known as Ghost chili, a native Capsicum species found in North East India was recorded as the naturally occurring hottest chili in the world by the Guinness Book of World Records in 2006. Although few studies have reported variation in pungency content of this particular species, no study till date has reported detailed expression analysis of candidate genes involved in capsaicinoids (pungency) biosynthesis pathway and other fruit metabolites. Therefore, the present study was designed to evaluate the diversity of fruit morphology, fruiting habit, capsaicinoids and other metabolite contents in 136 different genotypes mainly collected from North East India. Significant intra and inter-specific variations for fruit morphological traits, fruiting habits and 65 fruit metabolites were observed in the collected Capsicum germplasm belonging to three Capsicum species i.e., Capsicum chinense (Bhut jolokia, 63 accessions), C. frutescens (17 accessions) and C. annuum (56 accessions). The pungency level, measured in Scoville Heat Unit (SHU) and antioxidant activity measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay showed maximum levels in C. chinense accessions followed by C. frutescens accessions, while C. annuum accessions showed the lowest value for both the traits. The number of different fruit metabolites detected did not vary significantly among the different species but the metabolite such as benzoic acid hydroxyl esters identified in large percentage in majority of C. annuum genotypes was totally absent in the C. chinense genotypes and sparingly present in few genotypes of C. frutescens. Significant correlations were observed between fruit metabolites capsaicin, dihydrocapsaicin, hexadecanoic acid, cyclopentane, α-tocopherol and antioxidant activity. Furthermore, comparative expression analysis (through qRT-PCR) of candidate genes involved in capsaicinoid biosynthesis pathway revealed many fold higher expression of majority of the genes in C. chinense compared to C. frutescens and C. annuum suggesting that the possible reason for extremely high pungency might be due to the higher level of candidate gene(s) expression although nucleotide variation in pungency related genes may also be involved in imparting variations in level of pungency.

Rapid determination of capsaicinoids by colorimetric method

Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC), but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid–liquid extraction and liquid–liquid extraction in test tubes followed by a colorimetric analysis on the capsaicinoids by a selective chromogenic reaction with Gibbs reagent (2,6-dichloroquinone-4-chloroimide). In the comparison of the capsaicinoid content by the colorimetric method and HPLC using acetone extracts of fresh pepper and dry red pepper as samples, R² was 0.9973 and 0.9816, respectively, which shows a high linear correlation. In addition, a minimum of 1 μg/mL capsaicinoids can be detected and it was therefore determined that the method can efficiently analyze a great quantity of samples in a short time.

Protective effect of cyclodextrins on the quality parameters of roast preserved pepper

Total phenolics (TP), vitamin C, antioxidant activity and colour of preserved peppers were evaluated at 4, 25 and 50 ℃ storage during 30-day intervals. Except for 4 ℃, TP decreased during storage at 25 ℃ and 50 ℃, being softer for fortified samples with β-CDs. The protective effect was evident, since 50 ℃ samples containing β-CDs exhibited lower TP loss (19%) than control samples (38%) for 5 months storage. A decrease in the vitamin C content was observed for both samples as time and temperature progressed. In samples stored at 50 ℃ the protective effect of β-CD only was evident at the first month, since fortified samples showed lower vitamin C loss (10%) than control samples. The fortified samples with β-CDs exhibited lowest antioxidant activity loss (40%) during 90-day storage at 50 ℃, than control samples (64%). The colour changes were in line with those observed for total phenolics and at the end of study, the presence of 1% β-CDs delayed the darkening of samples at both (25 and 50 ℃) storage conditions.

ToF-SIMS imaging of capsaicinoids in Scotch Bonnet peppers (Capsicum chinense)

Peppers (Capsicum spp.) are well known for their ability to cause an intense burning sensation when eaten. This organoleptic response is triggered by capsaicin and its analogs, collectively called capsaicinoids. In addition to the global popularity of peppers as a spice, there is a growing interest in the use of capsaicinoids to treat a variety of human ailments, including arthritis, chronic pain, digestive problems, and cancer. The cellular localization of capsaicinoid biosynthesis and accumulation has previously been studied by fluorescence microscopy and electron microscopy, both of which require immunostaining. In this work, ToF-SIMS has been used to image the distribution of capsaicinoids in the interlocular septum and placenta of Capsicum chinense (Scotch Bonnet peppers). A unique cryo-ToF-SIMS instrument has been used to prepare and analyze the samples with minimal sample preparation. Samples were frozen in liquid propane, cryosectioned in vacuum, and analyzed without exposure to ambient pressure. ToF-SIMS imaging was performed at -110 °C using a Bi3 (+) primary ion beam. Molecular ions for capsaicin and four other capsaicinoids were identified in both the positive and negative ToF-SIMS spectra. The capsaicinoids were observed concentrated in pockets between the outer walls of the palisade cells and the cuticle of the septum, as well as in the intercellular spaces in both the placenta and interlocular septum. This is the first report of label-free direct imaging of capsaicinoids at the cellular level in Capsicum spp. These images were obtained without the need for labeling or elaborate sample preparation. The study demonstrates the usefulness of ToF-SIMS imaging for studying the distribution of important metabolites in plant tissues.