Impact of production and drying methods on the volatile and phenolic characteristics of fresh and powdered sweet red peppers

Effects of different hot-air drying methods on the dynamic changes in color, nutrient and aroma quality of three chili pepper (Capsicum annuum L.) varieties

The effects of constant and variable temperature hot-air drying methods on drying time, colors, nutrients, and volatile compounds of three chili pepper varieties were investigated in this study. Overall, the variable temperature drying could facilitate the removal of water, preserve surface color, and reduce the loss of total sugar, total acid, fat and capsaicin contents. Electronic-nose (E-nose) and gas chromatography-ion mobility spectroscopy (GC-IMS) analyses found that aldehydes, ketones, alcohols and esters contributed to the aroma of chili peppers. The drying process led to an increase in acids, furans and sulfides contents, while decreasing alcohols, esters and olefins levels. In addition, the three chili pepper varieties displayed distinct physical characteristics, drying times, chromatic values, nutrients levels and volatile profiles during dehydration. This study suggests variable temperature drying is a practical approach to reduce drying time, save costs, and maintain the commercial appeal of chili peppers.

Influence of the Drying Process on the Volatile Profile of Different Capsicum Species

Chili is a globally significant spice used fresh or dried for culinary, condiment, and medicinal purposes. Growing concerns about food safety have increased the demand for high-quality products and non-invasive tools for quality control like origin tracing and safety assurance. Volatile analysis offers a rapid, comprehensive, and safe method for characterizing various food products. Thus, this study aims to assess the impact of the drying process on the aromatic composition of various Capsicum species and to identify key compounds driving the aromatic complexity of each genetic makeup. To accomplish these objectives, the aroma was examined in fruits collected from 19 different pepper accessions (Capsicum sp.) belonging to four species: one ancestral (C. chacoense) and three domesticated pepper species (C. annuum, C. baccatum and C. chinense). Fresh and dried samples were analyzed using a headspace PTR-TOF-MS platform. Our findings reveal significant changes in the composition and concentration of volatile organic compounds (VOCs) from fresh to dried Capsicum. Notably, chili peppers of the species C. chinense consistently exhibited higher emission intensity and a more complex aroma compared to other species (both fresh and dried). Overall, the data clearly demonstrate that the drying process generally leads to a reduction in the intensity and complexity of the aromatic compounds emitted. Specifically, fresh peppers showed higher volatile organic compounds content compared to dried ones, except for the two sweet peppers studied, which exhibited the opposite behavior. Our analysis underscores the variability in the effect of drying on volatile compound composition among different pepper species and even among different cultivars, highlighting key compounds that could facilitate species classification in dried powder. This research serves as a preliminary guide for promoting the utilization of various pepper species and cultivars as powder, enhancing product valorization.

The effect of adding pomace on the bioactive composition and flavor volatiles in fermented orange juice with Lactobacillus

BACKGROUND

The consumption of oranges generates huge amounts of pomaces, which are the potential raw materials to increase the nutritional value of the products.

RESULTS

In this study, the bioactive composition and flavor volatiles in Lactobacillus fermented orange juice with added pomaces were researched. Results showed that the orange juices blended with pomaces were favorable substrates for Lactobacillus growth and the colony counts reached above 9.0 log CFU mL-1 , total phenolics, total flavonoids, and the antioxidant activity in orange juices were increased significantly after adding pomaces. Some amino acids, such as threonine (P < 0.0001), isoleucine (P < 0.01), and glycine (P < 0.01) were markedly higher in fermented orange juices with pomaces. The flavonoid diversity was more abundant by adding pomace fermentation and most flavonoids showed higher levels in fermented juices with the pomace, Lactobacillus fermentum 252 may transform some flavonoids through deglycosylation and reduction reaction. Furthermore, orange pomace mainly improved the flavor volatiles by increasing terpenoids and alcohol, such as d-limonene and benzyl alcohol, and decreasing volatile acids.

CONCLUSION

This study presented a novelty in elevating the nutritional value of juice by the utilization of pomaces, its findings can provide a new way to mine the bioactive ingredient from Citrus by Lactobacillus, and can be used as a guide for the development of new Citrus processing technologies and functional foods. © 2023 Society of Chemical Industry.

A simple and reliable QSPR model for prediction of chromatography retention indices of volatile organic compounds in peppers

Worldwide, various types of pepper are used in food as an additive due to their unique pungency, aroma, taste, and color. This spice is valued for its pungency contributed by the alkaloid piperine and aroma attributed to volatile essential oils. The essential oils are composed of volatile organic compounds (VOCs) in different concentrations and ratios. In chromatography, the identification of compounds is done by comparing obtained peaks with a reference standard. However, there are cases where reference standards are either unavailable or the chemical information of VOCs is not documented in reference libraries. To overcome these limitations, theoretical methodologies are applied to estimate the retention indices (RIs) of new VOCs. The aim of the present work is to develop a reliable QSPR model for the RIs of 273 identified VOCs of different types of pepper. Experimental retention indices were measured using comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GC × GC/qMS) using a coupled BPX5 and BP20 column system. The inbuilt Monte Carlo algorithm of CORAL software is used to generate QSPR models using the hybrid optimal descriptor extracted from a combination of SMILES and HFG (hydrogen-filled graph). The whole dataset of 273 VOCs is used to make ten splits, each of which is further divided into four sets: active training, passive training, calibration, and validation. The balance of correlation method with four target functions i.e. TF0 (WIIC = WCII = 0), TF1 (WIIC = 0.5 & WCII = 0), TF2 (WIIC = 0 & WCII = 0.3) and TF3 (WIIC = 0.5 & WCII = 0.3) is used. The results of the statistical parameters of each target function are compared with each other. The simultaneous application of the index of ideality of correlation (IIC) and correlation intensity index (CII) improves the predictive potential of the model. The best model is judged on the basis of the numerical value of R2 of the validation set. The statistical result of the best model for the validation set of split 6 computed with TF3 (WIIC = 0.5 & WCII = 0.3) is R2 = 0.9308, CCC = 0.9588, IIC = 0.7704, CII = 0.9549, Q2 = 0.9281 and RMSE = 0.544. The promoters of increase/decrease for RI are also extracted using the best model (split 6). Moreover, the proposed model was used for an external validation set.

Combining with volatilomic profiling and chemometrics to explore the volatile characteristics in five different dried Zanthoxylum bungeanum maxim

Owing to the short picking period of the fresh Zanthoxylum bungeanum, the postharvest drying has become an essential operation before the storage and transportation of Z. bungeanum. To explore the effects of drying methods on volatile characteristics, the volatilomic profiling of five different dried Z. bungeanum was investigated by E-nose, HS-SPME-GC/MS, GC-IMS in combination with chemometrics. The results indicated that W1W, W2W and W5S sensors within E-nose analysis showed the strongest responses in both fresh and dried Z. bungeanum. According to the identification of volatile organic compounds (VOCs), terpenes, esters and alcohols played the major roles in the volatile formation of the fresh and dried Z. bungeanum. The samples derived from hot air drying showed the relatively similar features with the fresh sample based on the relative abundances of these major VOCs. According to the results of multiple factor analysis (MFA), GC-IMS showed the strongest ability in distinguishing the fresh and different dried samples. Compared with the high levels of terpenes in fresh group, the significant increasement of terpene alcohols and terpene esters from the degradation and transformation of bound terpenoids was the main characteristics of all dried Z. bungeanum. Using the GC-IMS datasets, a weighted correlation network analysis (WCNA) model was constructed to clarify the VOC characteristics in all detetected samples. Thereinto, 6 significantly correlated modules were identified in fresh and five different dried samples. Additionally, a total of 23 hub VOCs can be recognized as the potential biomarkers for better distinguishing the fresh and five different dried Z. bungeanum.

Effect of the food matrix on the (poly)phenol stability of different plant-based meat products and their main ingredients after in vitro gastrointestinal digestion

The present study aimed to investigate the influence of the food matrix on the bioaccessibility of free and bound (poly)phenols in different plant-based foods. These plant-based matrices included two fresh raw materials (tomato and red pepper), two minimally processed intermediate ingredients (dehydrated tomato and roasted red pepper), and two final plant-based and spreadable meat products whose main ingredients were tomato and red pepper (tomato pâté and pepper pâté, respectively). All samples underwent harmonized INFOGEST in vitro gastrointestinal digestion to simulate the digestive process. In the six studied matrices, 75 (poly)phenolic compounds were detected, the free fraction, in general, being higher than the bound fraction. The bioaccessibility values fluctuated between 5.83 and 38.38%, while the colon available index ranged from 10.40-298.81%. Among phenolic acids and flavonoids, in general, flavonoids were more bioaccessible than phenolic acids. The highest bioaccessibility values were obtained for fresh raw tomato and tomato pâté, while the lowest values were obtained for roasted red pepper and pepper pâté. In conclusion, except for the tomato pâté, food processing was detrimental to polyphenol bioaccessibility.

Effects of Lentilactobacillus buchneri and Kazachstania bulderi on the Quality and Flavor of Guizhou Fermented Red Sour Soup

In this study, the effects of Lentilactobacillus buchneri (L. buchneri: CCTCC M 2023228) and Kazachstania bulderi (K. bulderi: CCTCC M 2023227) on the quality characteristics and volatile flavor substances in fermented red sour soup were explored based on natural fermentation. Compared to natural fermentation (nitrite: 5.5 mg/kg; amino acid nitrogen: 0.17 g/100 g; lycopene: 63.73 µg/mL), three fortified fermentation methods using L. buchneri, K. bulderi, and both strains together significantly reduced the concentrations of nitrite (2.62, 2.49, and 2.37 mg/kg), amino acid nitrogen (0.03 g/100 g, 0.02 g/100 g, and 0.05 g/100 g), and lycopene (26.64, 32.45, and 51.89 µg/mL). Total acid content (11.53 g/kg) and lactic acid bacteria count (285.9 ± 1.65 × 106 CFU/mL) were the elements most significantly increased by fortified fermentation with L. buchneri relative to other fermentation methods. A total of 99 volatile compounds were determined in red sour soup and could be roughly classified into alcohols, aldehydes, ketones, and esters. Fortified fermentation with two strains and fortified fermentation with K. bulderi increased the content of methyl butanoate and 3-hydroxybutan-2-one-acetoin (D). This study confirmed the effects of L. buchneri and K. bulderi on the quality and flavor of fermented red sour soup and provided a theoretical basis for the fortified fermentation of red sour soup.

Phenolic Compounds and Capsaicinoids in Three Capsicum annuum Varieties: From Analytical Characterization to In Silico Hypotheses on Biological Activity

The affinity of specific phenolic compounds (PCs) and capsaicinoids (CAPs) present in three Capsicum annuum varieties (Friariello, Cayenne and Dzuljunska Sipka) to the transient receptor potential vanilloid member 1 (TRPV1) was investigated by integrating an analytic approach for the simultaneous extraction and analysis through high-performance liquid chromatography coupled with ion trap mass spectrometry (HPLC/ITMS) and UV detection (HPLC-UV) of PCs and CAPs and structural bioinformatics based on the protein modelling and molecular simulations of protein-ligand docking. Overall, a total of 35 compounds were identified in the different samples and CAPs were quantified. The highest content of total polyphenols was recorded in the pungent Dzuljunska Sipka variety (8.91 ± 0.05 gGAE/Kg DW) while the lowest was found in the non-pungent variety Friariello (3.58 ± 0.02 gGAE/Kg DW). Protein modelling generated for the first time a complete model of the homotetrameric human TRPV1, and it was used for docking simulations with the compounds detected via the analytic approach, as well as with other compounds, as an inhibitor reference. The simulations indicate that different capsaicinoids can interact with the receptor, providing details on the molecular interaction, with similar predicted binding energy values. These results offer new insights into the interaction of capsaicinoids with TRPV1 and their possible actions.

Influences of Spices on the Flavor of Meat Analogs and Their Potential Pathways

This study evaluated the correlation between the sensory characteristics and spices of 50 commercial meat analogs and selected 4 spices to improve the flavor characteristics of soy protein concentrate (SPC) extrudates. Volatile compounds in extrudates and commercial meat analogs were investigated using headspace solid-phase microextraction and gas chromatography-mass spectrometry. The total concentrations of off-flavor volatile compounds in commercial products decreased with an increasing degree of processing. Furthermore, after adding spices during extrusion, the concentrations of volatile compounds such as aldehydes, alcohols, and furans related to thermal treatment decreased by approximately 5-39%, 5-15%, and 11-56%, respectively. Among them, compounds such as nonanal, 2-pentlyufuran, and 1-octen-3-ol, typical off-flavors in soy-based food, decreased by 8-42%, 11-55%, 2-52%, respectively. The correlation analysis between the antioxidative abilities of spices and volatile compounds showed that the contents of total phenolics were negatively correlated with the contents of ketones and alcohols in extrudates (p < 0.001). Moreover, the aroma-active compounds in extrudates were changed. More pleasant compounds, including alkanes and olefins, were observed by adding different spices as well. Especially in black pepper treated extrudates, the OAV value of off-flavor volatile compounds such as hexanal, octanal, 2-pentlyfuran decreased. In conclusion, the addition of spices can reduce off-flavor compounds related to thermal reactions, such as oxidation and the Maillard reaction, and impart newly pleasant flavors to extrudates during the extrusion of SPC. It is important to explore new methods that can be used to improve the flavor of extrudates so that consumers' preferences of meat analog products can be improved.

Photochemical advanced oxidative process treatment effect on the pesticide residues reduction and quality changes in dried red peppers

Pesticide residues in crops are widely monitored, and the residue reduction techniques at the post-harvest stage are important to maintain food safety. In dried crops, pesticide residues can be concentrated after dehydration, which increases concerns regarding residue risk. Therefore, the residue reduction effects of ultraviolet (UV), ozone, and photochemical advanced oxidative process (pAOP) were investigated for dried peppers at the post-harvest stage. UV₂₅₄ treatment reduced 59.7% of the residue concentration on average, while UV₃₆₀ showed a reduction of only 13.3% under 9.6 W m^-2 of UV exposure for 24 h. Gaseous ozone treatments reduced the residue concentrations up to 57.9% on average. In contrast, the pAOP treatment reduced the concentration up to 97% and was superior to UV or ozone treatment alone. Increased drying temperature under pAOP condition resulted in higher reduction ratios at 40-80 °C. The pAOP conditions with 12 and 24 µmol/mol of ozone and UV₂₅₄ irradiation for 24-48 h reduced the residue concentrations to 39-67%. Particularly, difenoconazole, fludioxonil, imidacloprid, and thiamethoxam residue concentrations were drastically reduced by over 50% under 12 µmol/mol ozone of the pAOP condition, while carbendazim, fluquinconazole, and pyrimethanil were relatively stable and their concentrations reduced below 50% under 24 µmol/mol ozone of the pAOP treatment. Various drying-related quality parameters of drying peppers such as water-soluble color, capsanthin, capsaicinoids, acid value, peroxide value, and thiobarbituric acid value were slightly altered, but not significantly, under 12 µmol/mol ozone of the pAOP condition, while the peroxide value was significantly altered under the higher ozone conditions. Therefore, pAOP treatment combined with gaseous ozone can be used for reducing residual pesticides in peppers without greatly reducing quality.

Impact of Japanese beetles (Popillia japonica Newman) on the chemical composition of two grape varieties (Nebbiolo and Erbaluce) grown in Italy

The effect of Japanese beetles (P. japonica) on critical quality indicators of Nebbiolo and Erbaluce grapes, specifically on their phenolic and volatile composition, was assessed. Adult beetle symptoms include extended skeletonization of leaves. Leaves are frequently left with their mid-vein intact but, when severely damaged, quickly turn brown. However, the plant tends to recover by generating a new leaf apparatus and the grapes reach ripeness. It emerged that the phenolic content of grapes produced by plants attacked by P. japonica (396 and 550 mg/kg, Nebbiolo and Erbaluce respectively) was generally higher when compared to healthy plants (266 and 188 mg/kg, Nebbiolo and Erbaluce respectively). Similarly, in the (red) Nebbiolo cultivar, the anthocyanin content was significantly lower in grapes produced with healthy plants. The influence of P. japonica on the volatile composition of Nebbiolo and Erbaluce grapes showed a total volatile fraction of affected grapes (433 and 439 µg/kg, respectively) significantly higher than the one related to healthy grapes (391 and 386 µg/kg, respectively). In response to the attack by P. japonica the plant significantly increases the content of some volatile compounds such as hexanal, (E)-2-hexenal, 1-hexanol, (E)-2-hexen-1-ol and phenyl ethyl alcohol.

Integrated transcriptomic and volatilomic profiles to explore the potential mechanism of aroma formation in Toona sinensis

As an important quality determinant of Toona sinensis, the unique aroma largely impacts the purchasing behavior of consumers. However, the underlying formation mechanism of the characteristic aroma of T. sinensis remains poorly understood. In this work, integrative volatile/nonvolatile compounds profiling and RNA sequencing were used to characterize six T. sinensis cultivars. Volatile sulfur compounds (VSCs) and terpenoids were the main volatile organic compounds (VOCs) in T. sinensis, accounting for 36.95-67.27% and 17.75-31.36% of the total VOC content, respectively. Notably, the VOCs originated from terpenoid biosynthesis, and the degradation of unsaturated fatty acids (UFAs) played important roles in reconciling the irritating odor of VSCs. The above differential metabolic profiles are the main sources of the specific aroma of different T. sinensis cultivars. Furthermore, 13 volatile organic compounds were identified as potential biomarkers to distinguish these T. sinensis cultivars by chemometric analysis. Based on the analysis of transcriptomic datasets, the potential biosynthetic pathways of the key VSCs were firstly confirmed in T. sinensis. It was found that 1-propenylsulfenic acid is a crucial precursor in the formation of characteristic VSCs in T. sinensis. Additionally, two potential mechanisms were proposed to explain the differences of the key VSCs among six T. sinensis cultivars. These results provide theoretical guidance for improving the aroma quality of T. sinensis.

Effect of infrared drying on chemical and microbial properties of Cold‐Hardy grape pomace (Edelweiss and Marquette)

This study aims to add value to a common wine industry waste by preserving bioactive compounds in cold-hardy grape pomace (GP) and preventing any microbial growth under the proper drying conditions. Effects of infrared (IR) and hot air (HA) drying on the microbial and physicochemical properties such as color, phenolic compounds, and antioxidant activity of white (Edelweiss) and red (Marquette) GP were studied. The IR heating rapidly reduced the moisture content of GP from 55% wet basis (w.b.) to less than 10%, which resulted in a drying time reduction of 71.9% to 80.2% compared to HA drying. There were no significant differences in color parameters among the IR- and HA-dried pomaces (p > .05). The phenolic content of 'Edelweiss' pomace was not significantly affected by both IR and HA drying, whereas the phenolic content of 'Marquette' pomace was substantially reduced from 274 mg/g dry extract in raw pomace to 127 mg/g dry extract after HA drying and to 141.9 mg/g dry extract after IR drying. Overall, the microbial load on the fresh pomace samples was dramatically reduced by IR heating, with a reduction of more than 99.9% when the pomaces were dried using IR at a temperature higher than 130°C. However, this high temperature of IR led to a significant reduction of DPPH antiradical scavenge activity for 'Edelweiss' pomace (p < .05). This study shows that using the IR approach, cold-hardy 'Edelweiss' and 'Marquette' grape pomaces can be efficiently dried with the antioxidant activity maintained, which could be used in a variety of food products as a functional ingredient.

Experimental Analysis of Drying Conditions’ Effect on the Drying Kinetics and Moisture Desorption Isotherms at Several Temperatures on Food Materials: Corn Case Study

This work studied the effect of external conditions on the drying kinetics of a thin layer of corn during convective drying. The density and the specific volume of the corn grain were reported and the desorption isotherms of the corn were determined at three temperatures and for a water activity from 0.1 to 0.9 using the static gravimetric method. Initially, a thin layer of corn about 7 mm thick with an initial moisture content of 45% (d.b) was investigated, and the external conditions were tested. Afterwards, a comparison between the experimental convective drying of a packed bed and a thin layer was performed under the same conditions. Finally, the values of equilibrium moisture contents, water activities and temperatures obtained were fitted using seven sorption models. It was found that the experimental desorption data exhibited type II behavior, according to Brunauer’s classification. The GAB model was found as the most suitable semi-empirical model which was well suited to represent the desorption equilibrium moisture content of corn kernels in the suggested ranges of temperature and water activity. It can be concluded from the entropy–enthalpy compensation theory that the desorption process of the corn kernels is controlled by the enthalpy mechanism.

Phytochemical analysis of Ziziphus jujube leaf at different foliar ages based on widely targeted metabolomics

Based on metabolomics, the metabolites of Jujube leaves LS1 (one bud and two leaves), LS2 (one bud and three leaves), and LS3 (one bud and four leaves) were taken and examined by ultra-high performance liquid chromatography-mass spectrometry technique. There were 22 substance categories that were identified. Principal component analysis was also utilized to distinguish the metabolomics at the three different foliar ages, and the results suggested that the samples at different foliar ages were clearly separated, demonstrating that the metabolites in the three foliar ages were significantly different. Through the screening of differential metabolites and hierarchical clustering analysis, our results suggested that the composition and the content distribution of the differential metabolites at three different foliar ages were significantly different. In the LS1, delphinidin, N-hydroxy tryptamine, serotonin, methylquercetin O-hexoside, tricin 7-O-hexoside, and eriodictyol C-hexoside were identified as the distinctive compounds. In the LS2, N-caffeoyl agmatine, lysoPC 18:3 (2n isomer), N-(4′-O-glycosyl)-p-coumaroyl-agmatine, dihydromyricetin, and hydroxy-methoxycinnamate were identified as the distinctive compounds. Similarly, the 3-O-p-coumaroyl-quinic acid, O-feruloyl 4-hydroxylcoumarin, isorhamnetin 3-O-neohesperidoside, cyanidin 3-O-galactoside, quercetin O-acetylhexoside, and DIMBOA glucoside were identified as the distinctive compounds in LS3. These characteristic compounds could provide a strong theoretical basis for rapid identification of jujube leaves at different foliar ages.

Flavour chemistry of dehydrated exotic fruits

Dehydrated fruit pieces and purées are commonly used in many food formulations and toppings for food products like yogurts, ice creams, and cereals. However, one of the biggest problems in fruit dehydration is the prevention of the development of unpleasant off-flavour that can negatively impact on the sensory quality of the final dried fruit products. In recent years, fruit dehydration has been conducted using either thermal or non-thermal drying techniques. Therefore, the present review examines how the different dehydration technologies, namely conventional hot air-drying, ultrasonic-assisted hot air-drying, sun-drying, spray-drying, Refractance WindowTM drying, cast-tape drying, thin-layer catalytic far-infrared radiation drying, withering, freeze-drying, microwave-drying, and osmotic dehydration impact on the volatile constituents of the final dried fruit products. Drying processes result in noticeable losses/reduction of several impact odorants. Moreover, some compounds are produced either via: (1) hydrolysis of relevant glycosides under high temperatures, or (2) thermal degradation of volatile and non-volatile precursors as well as oxidation and Maillard reactions which result in the production of heterocyclics, and saturated and unsaturated aldehydes. Of significance is the Refractance WindowTM drying which exhibits high retention potential (~ 90%) of volatile compounds present in fresh fruits. Refractance WindowTM drying technology ensures rapid drying of food products at very low temperature.

Elucidation of the impact of four different drying methods on the phenolics, volatiles, and color properties of the peels of four types of citrus fruits

BACKGROUND

Citrus fruit peels are considered to be process waste in the fruit juice industry but they are a valuable raw material due to their volatile and bioactive components. Drying is one of the most common methods to preserve this material. In this study, four drying processes were applied to the peels of four kinds of citrus fruits. The drying processes were convective drying (CD), microwave drying (MD), conductive hydro drying (CHD), and freeze drying (FD). The citrus fruits used were orange, bitter orange, grapefruit, and lemon.

RESULTS

The influence of dehydration on the aroma and phenolic composition, microstructure, and color properties were studied in detail. It was determined that drying increased the amount of both phenolics and volatiles in the dried samples. The MD and FD methods better preserved the color and phenolics of the samples, and the MD and CD processes increased the amount of aroma substances.

CONCLUSION

The MD method would be more suitable for drying citrus peels due to its shorter duration and its positive effects on the phenolic and aroma components. © 2022 Society of Chemical Industry.

Phenolic compounds of sugar beet (Beta vulgaris L.): Separation method, chemical characterization, and biological properties

Sugar beet (Beta vulgaris L.) is a good source of bioactive compounds. However, information on the biological properties of sugar beet root is limited and its beneficial effects have not been completely understood. In this work, 10 phenolic compounds have been separated and identified in various parts of sugar beet for the first time, including the most abundant epicatechin (31.16 ± 1.89 mg/100 g), gallic acid (30.57 ± 2.69 mg/100 g), and quercetin-3-O-rutinoside (30.14 ± 3.63 mg/100 g). The biological activity tests indicated that sugar beet peel potently scavenged the nitric oxide and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radicals with IC₅₀ values of 88.17 ± 05.14 and 28.77 ± 0.62 μg/ml, respectively. In addition, sugar beet peel exhibited the highest reducing power, IC₅₀ values of 11.98 ± 1.20 μg/ml, and the highest ion-chelating activity, IC₅₀ values of 48.52% and 55.21% for cupric and ferrous ions at 250 μg/ml, respectively. Compared to synthetic antioxidants, sugar beet showed promising biological activities, which could be considered further in future studies.

Comparative Elucidation of Aroma, Key Odorants, and Fatty Acid Profiles of Ivorian Shea Butter Prepared by Three Different Extraction Methods

In the present study, the volatile compounds, key odorants, and fatty acid profiles of Ivorian shea butter produced by cold press extraction (CPE), solvent extraction (SE) and traditional extraction (TE) methods were investigated for the first time. The aroma compounds of shea butter were extracted by the purge and trap method and analyzed by the gas chromatography–mass spectrometry and olfactometry (GC-MS/O) technique. Totals of 51, 49 and 46 aroma compounds were determined in samples from CPE, SE and TE, respectively. It was observed that the volatile compounds of studied material dominated after CPE, in which alcohols (11) were the most abundant chemical group, followed by aldehydes (10) and acids (7). The application of aroma extract dilution analysis (AEDA) resulted in 22, 20, and 16 key odorants in shea butter from CPE, SE and TE, respectively. 3-Hexanol with flavor dilution (FD) factors (2048 in CPS, 1024 in SE and 64 in TE) was found to be the most active aroma compound in all samples. In the fatty acid fraction obtained using the gas chromatography–flame ionization detector (GC-FID) method, 22, 24 and 19 fatty acids were detected in samples after CPE, SE and TE, respectively. The highest number of fatty acids was determined in shea butter using CPE (89.98%). Stearic and oleic acids were the most dominant fatty acids, and all samples of shea butter were rich sources of saturated fatty acids (SFAs). Moreover, the SE samples showed the highest values of DPPH (238.36 µM TEq/kg) and ABTS (534.96 µM TEq/kg), while the CPE samples had the highest total phenolic content (104.64 mg GAE/kg). Principal component analysis (PCA) clearly indicated that the extraction technique could quantitatively or qualitatively induce changes. Thus, this investigation demonstrated that extraction methods have a considerable impact on the quality and chemical composition of the presented material.

Effect of Combined Infrared and Hot Air Drying Strategies on the Quality of Chrysanthemum (Chrysanthemum morifolium Ramat.) Cakes: Drying Behavior, Aroma Profiles and Phenolic Compounds

Chrysanthemum (Chrysanthemum morifolium Ramat.) is a seasonal plant with high medicinal and aesthetic value, and drying is an effective practice to enhance its storability after harvesting. The effects of hot air drying (HAD), combined infrared and hot air drying (IR-HAD), and sequential IR-HAD and HAD (IR-HAD + HAD) on the drying behavior, color, shrinkage, aroma profiles, phenolic compounds, and microstructure of chrysanthemum cakes were studied. Results showed that the increasing temperature resulted in a decrease in drying time and an increase in drying rate and moisture diffusivity. The Logarithmic and Page models exhibited superior fit in describing the dehydration process. Among the three drying strategies, IR-HAD was more effective in reducing energy consumption, improving shrinkage, water holding capacity, water binding capacity and cellular microstructure, while IR-HAD + HAD showed better inhibitory effect on color deterioration. Furthermore, gas chromatography–mass spectrometry (GC-MS) analysis revealed that different drying strategies dramatically influenced the aroma profiles in samples, and IR-HAD obtained the highest concentration of volatiles. The results of ultra-performance liquid chromatography (UPLC) indicated that the introduction of infrared radiation contributed to increasing the contents of chlorogenic acid, luteolin, total phenolic and flavonoid. These suggested that IR-HAD was a promising technique for drying medicinal chrysanthemum.

Volatile composition changes in lemon during fruit maturation by HS-SPME-GC-MS

BACKGROUND

Volatiles are determinants of fruit aroma and flavor characteristics and also provide valuable information for lemon as ingredient for the food and drinks industry. Volatiles in 'Eureka' lemon and 'Xiangshui' lemon pulps from 130 to 186 days after flowering were enriched by headspace-solid-phase microextraction (HS-SPME), and analyzed by gas chromatography-mass spectrometry (GC-MS).

RESULTS

Seventy-seven volatiles of two lemon cultivars at the different ripening stages were identified and divided into six categories. Varieties and ripening stages had significant effects on individual volatiles in each category. The proportion of monoterpenes was found to be higher in 'Eureka' lemon, while 'Xiangshui' lemon had a higher proportion of sesquiterpenes, aldehydes and alcohols. The proportion of monoterpene fluctuation decreased during fruit ripening, while fluctuation of sesquiterpenes, alcohols, aldehydes and esters increased. Among the hydrocarbons, monoterpenes decreased their relative abundance from 91.67% to 81.04% in 'Eureka' lemon, and from 83.01% to 60.04% in 'Xiangshui' lemon; conversely, sesquiterpenes increased from 0.73% to 2.89% in 'Eureka' lemon, and from 3.21% to 8.48% in 'Xiangshui' lemon. Among the oxygenated volatiles, the proportions of alcohols, aldehydes and esters were higher at 186 days after flowering in both two cultivars.

CONCLUSION

The volatile organic compounds during fruit ripening of lemon varieties with different resistance were elucidated. The proportion of oxygenated volatiles increased during fruit ripening, and disease-resistant varieties had a higher proportion. These results provided important theoretical support for the utilization of lemon fruits and the innovation of disease-resistant germplasm resources. © 2021 Society of Chemical Industry.

Effect of different drying technologies on the characteristics and quality of lemon slices

This experiment aimed to investigate the effects of four drying methods, namely, hot air drying (HAD), microwave drying (MD), vacuum drying (VD), and microwave vacuum drying (MVD), on the quality of lemon slices. The relevant indicators, including total phenolic content, ascorbic acid content, browning, color, reducing sugar content, volatile component measurements, and principal component analysis of 0 and 30 days storage, were compared after exposure to the four drying methods. The shortest time of 64 min was used to treat the lemon slices via MVD at 1 KW. These samples displayed the least damage after drying and the highest rehydration ratio of 4.12. The contents of VC, reducing sugars, and total phenols of MVD samples were significantly higher than those in the HAD, VD, and MD groups, retaining 105.94 mg/100 g, 21.35 g/100 g, and 77.81 mg GAE/g, respectively, while their color difference values were also the smallest, with a browning degree of 3.55, significantly lower than those in the other treatment groups (p < 0.05), and the degree of browning of the samples in the HAD treatment group was the most serious; in terms of volatile flavor substances, the lemon slice samples in the MVD and HAD treatment groups were more diverse and of better quality. The order of product sensory evaluation was: MVD > VD > HAD > MD. The final scores after comprehensive analysis revealed the order of the four drying methods as MVD, HAD, VD, and MD. Therefore, MVD had a better effect on the sensory perception and nutritional properties of the lemon slices, providing a useful alternative to the conventional drying method. PRACTICAL APPLICATION: Lemon slices during drying are affected by various aspects, leading to changes in its color, aroma substances, and nutrient composition. The results of this work will not only provide a technical reference for the future production of high-quality dried lemon slices, but also have important implications for fresh-cut lemons in processing and storage. It also generates important implications for fresh-cut lemons in processing and storage.

The effects of drying methods and harvest season on piperine, essential oil composition, and multi-elemental composition of black pepper

This study aimed to evaluate the piperine content, essential oil composition, and multi-elemental composition of black pepper samples according to different drying methods and harvest season. Differences in essential oil composition and B, Ca, K, Mg, and S were noted according to sampling campaign, indicating secondary metabolism plant alterations. Mechanical drying resulted in essential oil composition changes due to high temperature exposure during processing. Increases in Fe and Cr contents when employing mechanical dryers with direct heating were also observed, due to direct contact with metallic structures and particulate material from the burning process. The As and Pb contents of several samples were higher than the maximum permissible limits, reaching 0.46 and 0.56 mg kg^-1, respectively, thus surpassing legislation safety limitations for human consumption.

Salt Stress Differentially Affects the Primary and Secondary Metabolism of Peppers (Capsicum annuum L.) According to the Genotype, Fruit Part, and Salinity Level

A total of four Capsicum annuum L. genotypes (‘Caro F1’, ‘Berenyi F1’, ‘Somborka’ and ‘Novosadka’) were exposed to two intensities of salt stress. We observed a significant decrease in the sugar content in all salt stressed treatments, except for the sucrose content of the pericarp of the ‘Caro F1’ cultivar. Salt stress had a largely negative effect on the total and individual organic acid content, although the effect differed among cultivars. Using high performance liquid chromatography coupled with a mass spectrometer, most phenolics were identified in the pericarp (18), followed by the placenta (7) and seeds (8). Treatment with 40 mM NaCl caused the highest increase in individual phenols, followed by treatment with 20 mM NaCl. The cultivar ‘Berenyi F1’ was less affected by salt stress treatment than the other three cultivars in terms of content of individual and total phenols. Salt stress increased the content of capsaicinoids in all the cultivars. The pericarp of the cultivar ‘Novosadka’ showed 17.5 and 50 times higher total capsaicinoid content than the control in the 20 mM and 40 mM NaCl, respectively. With the results of several metabolite groups, we confirmed that the reaction and metabolic content to salt stress within the genus Capsicum is genotype-, fruit part-, and salinity level-dependent.

Modulated Light Dependence of Growth, Flowering, and the Accumulation of Secondary Metabolites in Chilli

Chili is widely used as a food additive and a flavouring and colouring agent and also has great importance in health preservation and therapy due to the abundant presence of many bioactive compounds, such as polyphenols, flavonoids, carotenoids, and capsaicinoids. Most of these secondary metabolites are strong antioxidants. In the present study, the effect of light intensity and spectral composition was studied on the growth, flowering, and yield of chilli together with the accumulation of secondary metabolites in the fruit. Two light intensities (300 and 500 μmol m-2 s-1) were applied in different spectral compositions. A broad white LED spectrum with and without FR application and with blue LED supplement was compared to blue and red LED lightings in different (80/20 and 95/5%) blue/red ratios. High light intensity increased the harvest index (fruit yield vs. biomass production) and reduced the flowering time of the plants. The amount of secondary metabolites in the fruit varied both by light intensity and spectral compositions; phenolic content and the radical scavenging activity were stimulated, whereas capsaicin accumulation was suppressed by blue light. The red colour of the fruit (provided by carotenoids) was inversely correlated with the absolute amount of blue, green, and far-red light. Based on the results, a schematic model was created, representing light-dependent metabolic changes in chilli. The results indicated that the accumulation of secondary metabolites could be modified by the adjustment of light intensity and spectral composition; however, different types of metabolites required different light environments.

Evaluation of Phenolic Compounds and Pigments Content in Yellow Bell Pepper Wastes

Bell peppers are one of the most important species consumed and cultivated in Spain. Peppers are a source of carotenoids and phenolic compounds widely associated with biological activities such as antimicrobial, antiseptic, anticancer, counterirritant, cardioprotective, appetite stimulator, antioxidant, and immunomodulator. However, undersized and damaged fruits are usually wasted. Thus, in order to evaluate the phenolic content, a Box–Behnken design has been carried out to optimize the extraction from Capsicum annuum yellow pepper by ultrasound-assisted extraction (UAE). The independent factors were time (min), ethanol/water (% v/v) and solvent/sample ratio (v/w). The model was validated by ANOVA and confirmed. Furthermore, the whole pepper and the pepper without peduncles and seeds were extracted using optimal conditions and characterized by HPLC-ESI-TOF-MS. Moreover, their antioxidant activities, measured by three different methods (DPPH, ABTS, and FRAP), carotenoid composition, assessed by HPLC-MS, and chlorophyll content, assessed by a spectrophotometric method, were compared. A total of 38 polar compounds were found of which seven have been identified in pepper fruit extracts for the first time. According to the results, whole pepper (WP) samples presented higher content in phenolic acids; meanwhile, the edible portion (EP) was higher in flavonoids. No differences were found in the antioxidant activity except for the FRAP assay where the WP sample showed higher radical scavenging activity. EP samples showed the highest content of carotenoids and WP ones in chlorophylls.

Impacts of selected lactic acid bacteria strains on the aroma and bioactive compositions of fermented gilaburu (Viburnum opulus) juices

Gilaburu fruit and its products have gained popularity due to their nutritional content, taste and health benefits. Even though fermented gilaburu juice is widely preferred and consumed in some regions, there is no detailed study on the optimization of the production conditions of this popular beverage. In this study, gilaburu fruit juices fermented naturally (NFJ) and with three commercial lactic acid bacteria (LAB) (L. plantarum: FJLP, L. delbureckii: FJLD, L. caseii: FJLC) were examined for the first time. The microbial properties, phenolics, aroma compounds, minerals, amino acid contents and sensory properties were examined. It was found that the phenolics and volatiles were richer in the samples fermented with LAB but their amino acid contents were in lower amounts as compared to the NFJ sample. The juices produced with L. plantarum (FJLP) and L. delbrueckii (FJLD) presented better aroma, colour, flavour, and overall acceptability.

Characterization of Volatile Component Changes in Peas under Different Treatments by GC-IMS and GC-MS

Volatile profiles of peas under 9 kinds of different treatments including native, washing, blanching, precooling, freezing, steaming, boiling, frying, and freeze-drying were characterized by GC-IMS and GC-MS. The differences of volatile compounds in different peas were observed from the characteristic fingerprints by GC-IMS. The Venn diagram found that the common flavor substances codetected by GC-IMS and GC-MS were n-hexanal, nonanal, 1-octene-3-ol, benzaldehyde, 6-methyl-5-hepten-2-one, trans-2-octenal, and 2-ethyl-3,5-dimethylpyrazine, which were speculated to be the key flavor substances of peas. The cluster analysis of the heat map conducted towards the differences of volatile components in peas under different treatments; the results indicated that peas could be mainly divided into four groups, which was consistent with the above conclusion of GC-IMS. Eight sensory descriptors were used to evaluate the aroma notes: sweet flowers, fat fragrance, waxy aldehydes, mushroom hay, roasted potato with nuts, vegetable-like bean, spicy dry tar, and bitter almond from the sensory analysis, and the sensory analysis also showed good agreement with the results of GC-IMS and GC-MS. The results indicated that the volatile compounds of peas under different treatments could be visualized and identified quickly via GC-IMS, and the samples could be clearly classified based on the difference of volatile compounds. Practical Application. In the study, fingerprints coupled with cluster analysis were a visualized method for the identification of volatile compounds. Meanwhile, a new method, the Venn diagram with OAV, was used to identify the key-aroma of products. Finally, a rapid method is established to classify products by GC-IMS. In future practical applications, GC-IMS can be used to classify products from different origins and different manufacturers. Similarly, it can identify fake and inferior products and whether the products have deteriorated. In addition, this research will provide a new strategy to find the relationship between flavor compounds and various processed technology towards different cereals.

Effect of solvent polarity on the Ultrasound Assisted extraction and antioxidant activity of phenolic compounds from habanero pepper leaves (Capsicum chinense) and its identification by UPLC-PDA-ESI-MS/MS

Phenolic compounds are secondary metabolites involved in plant adaptation processes. The development of extraction procedures, quantification, and identification of this compounds in habanero pepper (Capsicum chinense) leaves can provide information about their accumulation and possible biological function. The main objective of this work was to study the effect of the UAE method and the polarity of different extraction solvents on the recovery of phenolic compounds from C. chinense leaves. Quantification of the total phenolic content (TPC), antioxidant activity (AA) by ABTS⁺ and DPPH radical inhibition methods, and the relation between the dielectric constant (ε) as polarity parameter of the solvents and TPC using Weibull and Gaussian distribution models was analyzed. The major phenolic compounds in C. chinense leaves extracts were identified and quantified by UPLC-PDA-ESI-MS/MS. The highest recovery of TPC (24.39 ± 2.41 mg GAE g^-1 dry wt) was obtained using MeOH (50%) by UAE method. Correlations between TPC and AA of 0.89 and 0.91 were found for both radical inhibition methods (ABTS⁺ and DPPH). The Weibull and Gaussian models showed high regression values (0.93 to 0.95) suggesting that the highest phenolic compounds recovery is obtained using solvents with "ε" values between 35 and 52 by UAE. The major compounds were identified as N-caffeoyl putrescine, apigenin, luteolin and diosmetin derivatives. The models presented are proposed as a useful tool to predict the appropriate solvent composition for the extraction of phenolic compounds from C. chinense leaves by UAE based on the "ε" of the solvents for future metabolomic studies.

Efficacy of green waste-derived biochar for lead removal from aqueous systems: Characterization, equilibrium, kinetic and application

The removal of toxic metals from the aquatic ecosystem is one of the most pressing environmental and public health concerns today. A strong potential has recently emerged for the removal of such metals using biochar sorbents. Biosorption technology could make a significant difference in the future. It is a viable and cost-effective alternative to the remediation of toxic pollutants utilizing various biomaterials. In the current study, batch and fixed-bed studies were performed to evaluate the performance of Capsicum annuum L. seeds biochar (CASB) as an alternative material in removing toxic Pb(II) from aqueous solutions. Removal characteristics were investigated by considering the equilibrium and kinetic aspects. Biosorption equilibrium was established within 40 min. The optimum dosage of CASB for Pb(II) removal was determined as 2.0 g L^-1. Biosorption data were well predicted by a non-linear Langmuir isotherm model. Monolayer biosorption occurred for CASB with a maximum capacity of 36.43 mg g^-1. Biosorption kinetics fitted well with a pseudo-first-order kinetic model. The external mass transfer may control Pb(II) transport mechanism. Dynamic flow mode biosorption and regeneration potential of CASB were also examined. The application of CASB exhibited a 100% removal yield in real apple juice samples spiked with low concentrations of Pb(II). Exhausted points for the CASB packed columns were recorded as 195 and 320 min for simulated wastewater (SW) and synthetic Pb(II) solution, respectively. FTIR, BET, SEM-EDX analysis, and zeta potential measurements were used for the characterization of biochar and assessment of the metal ion-biosorbent interaction mechanism. Finally, our study provides a practical approach for the uptake of Pb(II) ions from contaminated solutions.