Investigation into the use of novel pretreatments in the fermentation of Alaria esculenta by Lactiplantibacillus plantarum and kombucha SCOBY

High pressure processing (HPP), ultrasound probe (USP) and ultrasound bath (USB) were applied to Alaria esculenta as a fermentation pre-treatment. Seaweed was then fermented by Lactiplantibacillus plantarum (LAB) or symbiotic culture of bacteria and yeast (SCOBY). Physiochemical properties of fermented seaweed were measured. pH was significantly different (p < 0.05) across SCOBY-fermented samples with different pre-treatments but not LAB-fermented samples (p > 0.05). There was a significant difference (p < 0.05) in total viable count (TVC) with the highest count in HPP-treated samples, and lowest in control samples. Organic acids differed significantly (p < 0.05) across pre-treatments for both fermentation groups. 27 volatile compounds were detected in the samples, with alcohols and ketones the most prominent groups. The quantity of volatile compounds was not significantly lower (p > 0.05) from seaweed powder. The control sample had the highest levels of tropomyosin (15.92 mg/kg) followed by HPP samples.

Antioxidant Capacity, Sugar Content, and Tandem HPLC-DAD-ESI/MS Profiling of Phenolic Compounds from Aronia melanocarpa Fruits and Leaves (Nero and Viking Cultivars)

This study examined the phenolic profile, sugar composition, and antioxidant capacities of chokeberry fruits and leaves obtained from four different Turkiye provinces. A total of 21 phenolics including phenolic acid and its derivatives, flavanols, anthocyanins, and flavonols were determined in the fruits, while the leaves had 19 phenolics, including phenolic acid and its derivatives, flavanols, and flavonols. The total amount of phenolic compounds was the highest in both fruits and leaves in the samples from the Bursa province. Cis 5-O-p-coumaroylquinic acid and secoxyloganin were quantified for the first time in both fruits and leaves. In summary, it was found that different geographical locations significantly affected the phenolics, sugar contents, and antioxidant activities of the fruits and leaves.

Correction: Kelebek et al. Exploring the Impact of Infusion Parameters and In Vitro Digestion on the Phenolic Profile and Antioxidant Capacity of Guayusa (Ilex guayusa Loes.) Tea Using Liquid Chromatography, Diode Array Detection, and Electrospray Ionization Tandem Mass Spectrometry. Foods 2024, 13, 694

In the original publication [...].

Exploring the Impact of Infusion Parameters and In Vitro Digestion on the Phenolic Profile and Antioxidant Capacity of Guayusa (Ilex guayusa Loes.) Tea Using Liquid Chromatography, Diode Array Detection, and Electrospray Ionization Tandem Mass Spectrometry

Guayusa tea is derived from the leaves of the Ilex guayusa Loes. plant, which is native to the Amazon rainforest. Beyond its pleasant sensory properties, Guayusa tea is rich in antioxidants, phenolics, and minerals. In this study, the effects of infusion time, temperature, and solvent conditions on the color, antioxidant capacity, total phenolic content, phenolic profile, and antimicrobial activity of Guayusa (Ilex guayusa Loes.) tea were investigated. Guayusa tea samples were prepared using two different solvents, ethanol and water, with 4, 6, and 8-h infusions at 60 and 70 °C. Liquid chromatography, diode array detection, and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) were used to determine a comprehensive profile of phenolic compounds and to detect differences due to infusion conditions. Moreover, after the Guayusa tea infusion with the highest bioactive properties was determined, the effects of in vitro gastrointestinal digestion on the total phenolic content, antioxidant capacity, and phenolic compounds of the Guayusa tea infusion were measured. Phenolic profile analysis identified 29 compounds, among which chlorogenic acid and its derivatives were predominant. The increase in infusion time was correlated with an elevation in total phenolic content. Significant differences were observed between water and ethanol infusions of Guayusa in terms of phenolics and antioxidants. The total amount of phenolic compounds in the samples prepared with both solvents was found to increase after oral intake, depending on the digestion stage; meanwhile, the amounts of flavonoid compounds and di-O-caffeoylquinic acid derivatives decreased during digestion.

Impact of different salt concentrations on growth, biochemical composition and nutrition quality of Phaeodactylum tricornutum and Spirulina platensis

The effects of different salt concentrations on the growth, aroma and quality parameters of P. tricornutum and S. platensis were investigated for the first time.Salt contents were 15, 25, 30 and 35‰ for the P. tricornutum and 20, 25, 30 and 35‰ for the S. platensis culture. Aroma compounds were analyzed by HS-SPME-GC/MS while the organic acid and sugar composition were studied by HPLC-PDA-RID.The main amino acids were glutamic acid (6.24-12.96 mg/100 g) and alanine (3.67-13.65 mg/100 g) while the prevailing sugars were sucrose (229-1099 mg/100 g) and glucose (192-2322 mg/100 g) in the P. tricornutum and S. platensis samples.The most prevailing aroma compound was acetic acid (113 µg/kg) in the P. tricornutum samples and heptadecane (36941 µg/kg) in the S. platensis samples.A significant reduction was found in the amount of aroma compounds, amino acids, sugars and organic acids with increasing salt concentration.The study results are valuable for producing high-quality and flavorful P. tricornutum and S. platensis products.

Optimization of complex coacervation parameters for the production of encapsulated black garlic using response surface methodology

The purpose of this study was to optimize black garlic encapsulation parameters (core/coating ratio, extract concentration, and coacervate/maltodextrin [MD] ratio) using central composite design of the response surface methodology based on encapsulation efficiency (EE) (%). The optimum parameters were determined as 4.0 for the coating material/core ratio, 50% for the extract concentration, and 6.0 for the MD/coacervate ratio depending on the EE (%). The antioxidant activity values were determined as 101 and 134 µmol Trolox/100 g dry weight (DW) for the 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) methods, respectively, whereas the total phenolic content was 49 mg gallic acid equivalent/100 g DW for the encapsulated black garlic samples. S-Allyl-l-cysteine (SAC), γ-l-glutamyl-SAC (GSAC), γ-l-glutamyl-(S)-trans-1-propenyl-l-cysteine, and allicin were the organosulfur (OS) compounds determined in the samples. The SAC concentration of the encapsulated black garlic samples was determined as 22.36 mg/g, whereas the GSAC content was found at a lower concentration (0.33 mg/g) compared to SAC. The allicin content was quantified to be 0.31 mg/g. The encapsulated samples were also characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The FT-IR analysis revealed specific functional groups, including hydroxyl, carbonyl, and glycosidic linkage. The interaction between lentil protein isolate and pectin was strong enough to encourage capsule formation as visualized in the SEM images. This study shows the potential of black garlic coacervates as a functional ingredient for the food industry due to their stability, solubility, and preservation of OS and antioxidant compounds.

Effect of Salt Stress on the Phenolic Compounds, Antioxidant Capacity, Microbial Load, and In Vitro Bioaccessibility of Two Microalgae Species (Phaeodactylum tricornutum and Spirulina platensis)

Microalgae have gained attention as alternative food sources due to their nutritional value and biological effects. This study investigated the effect of salt stress on the antioxidant activity, phenolic profile, bioavailability of bioactive compounds, and microbial counts in the blue-green algae Spirulina platensis and diatom species Phaeodactylum tricornutum. These microalgae were cultured in growth mediums with different salt concentrations (15-35‱) We observed the highest antioxidant activity and phenolic compounds in the control groups. S. platensis (20‱) exhibited higher antioxidant activity compared to P. tricornutum (30‱), which decreased with increasing salt stress. Using HPLC-DAD-ESI-MS/MS, we identified and quantified 20 and 24 phenolic compounds in the P. tricornutum and S. platensis culture samples, respectively. The bioavailability of these compounds was assessed through in vitro digestion with the highest amounts observed in the intestinal phase. Salt stress negatively affected the synthesis of bioactive substances. Microbial counts ranged from 300 to 2.78 × 104 cfu/g for the total aerobic mesophilic bacteria and from 10 to 1.35 × 104 cfu/g for yeast/mold in P. tricornutum samples while the S. platensis samples had microbial counts from 300 to 1.9 × 104 cfu/g and the total aerobic mesophilic bacteria from 10 to 104 cfu/g, respectively. This study suggests that adding salt at different ratios to the nutrient media during the production of P. tricornutum and S. platensis can impact phenolic compounds, antioxidant capacity, microbial load evaluation, and in vitro bioaccessibility of the studied microalgae.

Comparative elucidation on the phenolic fingerprint, sugars and antioxidant activity of white, orange and purple-fleshed sweet potatoes (Ipomoea batatas L.) as affected by different cooking methods

In this study, three cooking methods (baking, boiling, sous vide (SV)) were applied to Turkish sweet potatoes with three flesh colors (white, orange, purple) to examine the effects of the product color and cooking methods on the total phenolics, antioxidant activity, sugars, phenolic acids, and anthocyanins. LC-MS-MS was employed in the characterization of these compounds. It was observed that the product color and cooking method significantly affected the concentrations of bioactive compounds like polyphenols. Both the highest total phenolic content (11.36 mg/g) and antioxidant activity (DPPH (50.3 μM TE/g) and ABTS (63.53 μM TE/g)) were determined in the purple sweet potato cooked with the SV method. 10 phenolic acids were quantified in all samples which were in the highest amounts in the orange colored samples followed by the purple samples. Baking resulted in the highest total phenolic acids in all samples. 13 anthocyanins were detected in the purple-colored samples, while the SV cooking best preserved the anthocyanins. In sum, purple sweet potatoes cooked by SV are recommended for higher phenolic contents, antioxidant capacity and anthocyanins.

Changes in the aroma and key odorants from white garlic to black garlic using approaches of molecular sensory science: A review

Black garlic is a relatively new product that has become very popular in recent years. It is obtained by fermenting raw (white) garlic by the application of heat treatment. The undesirable pungent odor of the white garlic disappears and the black garlic product with a sweet-sour flavor is formed after various reactions during the applied heat process. As a result, black garlic is more preferred and easily consumed by the consumers compared to white garlic. This review aims to summarize the studies on the changes in the odorants during the heat treatment employed in the production of black garlic as well as the factors affecting the changes in the aroma and aroma-active compounds and the use of molecular sensory science (MSS) approach, which has been applied in recent years as a new method for the determination of the aroma compounds. This work revealed that the use of the MSS on the aroma changes in black garlic is quite limited in the literature. Thus, more studies are needed to understand the aroma changes that occur during the formation of black garlic from white garlic in more detail.

A comprehensive review of recent development in extraction and encapsulation techniques of betalains

Betalains are attractive natural pigments with potent antioxidant activity, mainly extracted from the roots, tubers, leaves, flowers, and fruits of certain plants and some fungi. They constitute a reliable alternative to synthetic dyes used in the food industry and are considered toxic for consumers. In addition, there is convincing evidence of their health benefits for consumers. However, betalains are highly unstable to environment factors, such as light, heat, oxygen, water activity, and pH change which can be degraded during food processing, handling, storage, or delivery. Therefore, newly developed extraction methods and micro/nano-encapsulation techniques are currently applied to enhance the extraction yield, solve their instability problems, and improve their application in the food industry. This article aims to summarize the new advanced extraction methods of betalains, discussing the recent encapsulation techniques concerning the different encapsulating materials utilization. Betalains, natural pigments with potent antioxidant activity, are increasingly extracted from the roots, tubers, leaves, flowers, and fruits of certain plants and some fungi as safe alternatives to synthetic food dyes used in the food industry. However, their susceptibility to degradation during food processing, storage, and delivery poses challenges. Recent developments in extraction methods (e.g., supercritical fluid, pressurized liquid, ultrasound- and microwave-assisted, and enzyme-assisted) enhance betalain recovery, minimizing degradation. Encapsulation techniques using biopolymers, proteins, lipids, and nanoparticles protect betalains from environmental factors, extending shelf life and enabling controlled release. These advancements offer improved extraction efficiency, reduced solvent use, shorter processing times, and enhanced stability. Integration of these techniques in the food industry presents opportunities for incorporating betalains into various products, including functional foods, beverages, and dietary supplements. By addressing stability challenges, these developments support the production of innovative, healthier food items enriched with betalains. This article provides an overview of recent advancements in betalain extraction and encapsulation, highlighting their potential applications in the food industry.

GC-MS-Olfactometric characterization of key odorants in rainbow trout by the application of aroma extract dilution analysis: Understanding locational and seasonal effects

The effect of seasonal and regional differences of rainbow trout on its aroma and aroma-active profile was investigated. Solvent-assisted flavor evaporation (SAFE) procedure was employed for the aroma extraction while Gas Chromatography-Mass Spectrometry-Olfactometry (GC-MS-O) and aroma extract dilution analysis (AEDA) were utilized to assess the aroma-active substances. The olfactometric analysis indicated seasonal and regional differences in the aroma-active compounds contributing to the characteristic odours of the trout samples and the compounds were more intense in autumn and winter. The strongest aroma-actives were hexanal (green), acetoin (buttery, green), limonene (citrus), 2-hexanol (green, pungent) and 1-octen-3-ol (oily, mushroom). The findings of this study can provide useful information for the selection of rainbow trout based on the seasons and locations in terms of marketing and consumer preference.

Valorization of cocoa, tea and coffee processing by-products-wastes

The growing threat of food insecurity together with some challenges in demography, health, malnutrition, and income instability around the globe has led researchers to take sustainable solutions to ensure secure production and distribution of food. The last decades have been remarkable in the agri-food supply chain for many food industries. However, vast quantities of food by-products and wastes are generated each year. These products are generally disposed in the environment, which could have remarkable adverse effects on the environment and biodiversity. However, they contain significant quantities of bioactive, nutritional, antioxidative, and aroma compounds. Their sustainable use could meet the increased demand for value-added pharmaceutical, nutraceutical, and food products. The amount of agri-food wastes and their disposal in the environment are predicted to double in the next decade. The valorization of these by-products could effectively contribute to the manufacture of cheaper functional food ingredients and supplements while improving regional economy and food security and mitigating environmental pollution. The main aim of this chapter is to present an understanding of the valorization of the wastes and by-products from cacao, coffee and tea processing with a focus on their bioactive, nutritional, and antioxidant capacity.

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.

Effect of the main constituents of Pistacia lentiscus leaves against the DPPH radical and xanthine oxidase: experimental and theoretical study

The aim of this work is to study the content of phenolic compounds in P lentiscus leaves and their antioxidant effect. After extracting the phenolic compounds, fractionation by liquid/liquid partition with increasing polarity gives five extracts. Three of them (ButF, AqF and ButA) were found to have good antioxidant activity. Their IC_50s for the inhibition of the free radical formation of DPPH are 1.76 µg/mL, 1.307 µg/ml, and 1.77 µg/mL, respectively. These values are very interesting, considering the effect of the powerful flavonoid quercetin, whose IC₅₀ against DPPH is 1.53 µg/mL. These extracts are also active against xanthine oxidase (XO). The IC_50s measured are 0.14 mg/mL, 0.186 mg/mL and 0.33 mg/mL for ButF, Aq F and ButAq F extract respectively, in comparison with allopurinol (0.44 mg/mL). A phytochemical analysis by LC/ESI-MS-MS was performed to explain the observed activities. The results show 22 peaks representing: flavanols, namely catechin, d-Gallocatechin, and gallocatechin gallate. The only flavone detected in the studied extracts was luteolin glucuronide and was found to be in higher amounts in butanolic extract (2,71mg/mL). The phenolic acids and derivatives were also identified in the extracts. A theoretical study was performed to deduce the specificity of the binding between the major compounds identified in the P. lentiscus extract and the xanthine oxidase enzyme using Schrödinger software. The docking procedure was validated using the extraction of ligands from the binding site. Their re-anchoring to the xanthine oxidase structure using quercetin and allopurinol was considered reference molecules. After docking, post-docking minimization was performed to achieve the best scoring poses with the MM-GBSA approach. The dGBind energy of MM-GBSA representing the binding energy of the receptor and the ligand was calculated based on molecular mechanics. Results reveal that β-Glucogallin compounds such as Digalloylquinic acid, Gallocatechin, and Myricetin-3-O rhamnoside are more active than allopurinol, with stronger Docking score (Gscore) and MM-GBSA dGBind.Communicated by Ramaswamy H. Sarma.

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.

Application of Molecularly Imprinted Polymers for the Detection of Volatile and Off-Odor Compounds in Food Matrices

Molecularly imprinted polymers (MIPs) are synthetic receptors having specific cavities intended for a template molecule with a retention mechanism that depends on molecular recognition of the targeted constituent. They were initially established for the detection of minor molecules including drugs, pesticides, or pollutants. One of the most remarkable areas where MIPs have potential utilization is in food analysis, especially in terms of volatile compounds which are found in very low concentrations in foods but play a crucial role for consumer preference and acceptance. In recent years, these polymers have been used extensively for sensing volatile organic and off-odor compounds in terms of food quality for selective high-extraction purposes. This review first summarizes the basic principles and production processes of MIPs. Second, their recent applications in the separation, identification, and quantification of volatile and off-odor compounds in food samples are elucidated.

Grape seed oil volatiles and odour activity values: a comparison with Turkish and Italian cultivars and extraction methods

Valorization of bioactive-rich wastes of food industry, such as grape seeds, is one of the most popular topic worldwide. The present study is designed to examine the volatiles of grape seed oils obtained by two Turkish (cvs. Okuzgozu and Emir) and two Italian (cvs. Sangiovese and Moscatello) cultivars by using two well-known oil extraction methods, cold percolation (CP) and soxhlet (SX). In order to evaluate their volatile composition, obtained oil extracts were subjected to purge and trap aroma extraction chamber combined with gas chromatography-mass spectrometry GC-MS. Revealed results showed that the oil yield, volatile compositions and odor activity values (OAVs) of grape seed oils altered depending on both variety and extraction method of the oil. According to results, a total of 60 and 67 volatile compound were detected in CP and SX aromatic extracts. High temperature applied during SX led to form new volatiles and increase in overall volatile composition due to oxidation reactions. Among all aroma groups, alcohols were the dominating aroma group followed by esters in each cultivar for both extraction methods. GSOs obtained by red grape varieties exhibited apparently higher ester concentration while white varieties were abundant in terpenes. Additionally, SX method caused to form some heat derived volatiles. Moreover, a total of 26 and 33 aroma compounds possessed OAVs greater than 1 and ethyl octanoate (sweet-apple odour), nonanal (fatty-citrus odour) and 1-octen-3-ol (mushroom, earthy odour) were found to be dominant volatiles with respect to their OAVs.

Comparative elucidation of colour, volatile and phenolic profiles of black carrot (Daucus carota L.) pomace and powders prepared by five different drying methods

Black carrot pomace is a juice industry by-product that can be easily spoiled due to its high moisture content and usually considered as waste; however, it is a valuable product with high amount of bioactive compounds that can be recovered for further application in several industrial fields. Drying is an effective method for the preservation of this product. Thus, the influence of five drying methods (FD: freeze drying, MWD: microwave drying, CD: convective drying, VCD: vacuum/convective drying, CHD: conductive hydro drying) on colour, phenolics and volatiles of pomace were investigated. Findings revealed that drying process decreased the amount of anthocyanins, colourless phenolics and volatile compounds. CHD resulted in similar colour quality and yielded a better preservation of colour and phenolics while FD provided dried sample with an aroma quality similar to fresh sample. The shorter duration of the CHD makes it a better choice.

Impacts of novel blanching treatments combined with commercial drying methods on the physicochemical properties of Irish brown seaweed Alaria esculenta

Alaria esculenta is one of the most abundant edible brown seaweeds in Irelandandisconsidered an excellent source of nutrients, sought after by the food, nutraceutical and pharmaceutical industries. Seaweed is typically blanched and dried prior to consumption to enhance the end-product quality attributes and shelf life. Three blanching techniques were examined in this work; conventional hot water blanching, novel ultrasound blanching and microwave blanching. The L* and b*colour metrics were affected significantly (P < 0.01) by the processing methods. There were 76 volatile compounds detected in blanched and dehydrated Alaria esculenta. Freeze-dried samples after treatment with microwave alone (at 1000 W) and microwave (800 W) combined with ultrasound (at 50% amplitude) had the highest retention rate of volatile compounds (up to 98.61%). Regarding mineral content, drying methods significantly affected (P < 0.05) the content of Ca, Co, Cu and Fe, while blanching treatments significantly affected (P < 0.05) the content of Na, Cu, Fe and Mn.

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.

Elucidation of Volatiles, Anthocyanins, Antioxidant and Sensory Properties of cv. Caner Pomegranate (Punica granatum L.) Juices Produced from Three Juice Extraction Methods

This study deals with the characterization of the phytochemical profiles and antioxidant activities of cv. Caner pomegranate (Punica granatum) juices obtained from three different juice extraction methods including halved pomegranate (HPJ), arils (AJ), and macerated arils (MAJ) extraction for the first time. It was found that the type of the juice extraction process had substantial effects on the volatiles, anthocyanin compositions, and antioxidant activities of the samples. Results showed that the AJ sample (593 mg L^-1) had more anthocyanin compounds followed by HPJ (555 mg L^-1) and MAJ (408 mg L^-1) samples. GC-MS analysis revealed a total of 34 volatile compounds. The highest number of volatiles was found in the MAJ sample (1872 µg L^-1); thus, the aril maceration process played an important role in increasing the volatiles as compared to the HPJ (751.8 µg L^-1) and AJ (710.7 µg L^-1) samples. Sensory analysis showed that the HPJ sample was the most preferred and its general impression was higher as compared to the AJ and MAJ samples. The findings of this study elucidated that the juice extraction technique had a significant influence on the phytochemical profiles, sensory quality, and antioxidant activity of pomegranate juices.

Variations in the key aroma and phenolic compounds of champignon (Agaricus bisporus) and oyster (Pleurotus ostreatus) mushrooms after two cooking treatments as elucidated by GC-MS-O and LC-DAD-ESI-MS/MS

Volatiles, key odorants, phenolics and antioxidant properties of raw, boiled and oven-cooked champignon and oyster mushrooms were investigated. Total concentration of the volatiles was drastically reduced by both cooking treatments and the lowest contents were found in the oven-cooked sample. Alcohols and terpenes were the dominant aroma groups in the raw champignon and oyster sample, respectively. The highest FD factor (FD = 2048) was found for 1-octen-3-one and methional in raw and boiled champignon samples while the same FD factor was determined in 1-octen-3-ol and methional in raw and boiled oyster samples. It was determined that the phenolics were more abundant in champignon samples than the oyster samples and that the boiling process caused a decrease while oven-cooking resulted in an increase in the amount of phenolics in both varieties. It was revealed that cooking was a crucial factor for the key odorants and phenolics in champignon and oyster mushrooms.

LC-DAD-ESI-MS/MS-based assessment of the bioactive compounds in fresh and fermented caper (Capparis spinosa) buds and berries

The main objective of this study was to compare bioactive compounds and other important quality parameters of fresh and fermented caper buds and berries. Fresh samples were fermented using dry-salted and brined techniques. The higher phenolic content was determined in the fresh (1843.71 mg/100 g DW) and fermented buds (1198.54-1539.49 mg/100 g DW) rather than the berries (29.72-40.75 mg/100 g DW). Quercetin-3-O-rutinoside, kaempferol-3-O-rutinoside, and quercetin-O-galloly-O-hexoside were the principal phenolic components in fresh and fermented buds while quercetin-3-O-rutinoside in fresh and fermented berries. The amounts of isorhamnetin, quercetin, and kaempferol increased in fermented buds and berries compared to fresh samples. Similarly, antioxidant capacity of buds was found to be markedly higher than berries. As for sugar compounds, it was found that fructose in buds (1.56-3.23 g/100 g DW) and glucose in berries (1.96-6.38 g/100 g DW) had the highest amount. When total phenolics and antioxidant properties were evaluated, it was observed that they were better preserved in the dry-salted samples than the brined samples.

Elucidation of aroma-active compounds and chlorogenic acids of Turkish coffee brewed from medium and dark roasted Coffea arabica beans

Turkish coffee is a popular hot beverage owing to its delicious taste and pleasant aroma in Turkey. In the present study, key odorants of medium (MRC) and dark roasted Turkish coffee (DRC) brews were studied using GC-MS-Olfactometry. A total of 26 and 28 key odorants were detected in the MRC and DRC samples, respectively, with flavour dilution (FD) factors varying between 4 and 2048. The highest FD factor (2048) was found for 2-ethyl-3,5-dimethylpyrazine and 2-ethyl-3-methyl pyrazine in the MRC and DRC brew samples, respectively. One of the main differences between the two brew samples was the guaiacol with phenolic-burnt odour. A higher amount of chlorogenic acids (CGAs) was determined in the MRC as compared to the DRC using LC-DAD-ESI-MS/MS. According to the sensory analysis, the Turkish coffee sample brewed from the MRC beans had a higher score of general impression and pleasant coffee sensory descriptors as compared to the DRC.

Characterization of Aroma-Active Compounds, Phenolics, and Antioxidant Properties in Fresh and Fermented Capers (Capparis spinosa) by GC-MS-Olfactometry and LC-DAD-ESI-MS/MS

Caper (Capparis spinosa) is an important food ingredient whose fresh parts, particularly the flower buds, are consumed as a starter with olives, cheese, and nuts, or are used as a component in other foods. It is one of the most popular species of aromatic plants grown in the Mediterranean zone. Fermentation makes the caper edible and affects the overall aroma as well as sensory and nutritional characteristics. This study aimed to evaluate the changes in aroma, aroma-active, and phenolic compounds of caper as affected by fermentation. Purge and trap method was used for the extraction of the aroma compounds, while gas chromatography-mass spectrometry olfactometry and Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) were employed for the detection of aroma-active compounds and phenolics, respectively. The results showed that the total amount of aroma compounds decreased drastically (62,616 to 21,471 µg/kg) in fermented sample. Twelve and 10 aroma-active compounds were detected in fresh and fermented caper buds, respectively, for the first time by the application of aroma extract dilution analysis. Among these compounds, methyl isothiocyanate (flavor dilution [FD] factor = 512) in fresh caper and acetic acid (FD factor = 128) in the fermented caper had the highest FD factor. With regard to the phenolic compounds, a total of 16 components were identified in fresh and fermented capers. As observed in aroma compounds, the total phenolic concentration decreased as a result of fermentation. Two phenolic compounds being kaempferol-3-O-glucosyl-rhamnosyl-glucoside and isorhamnetin hexoside were newly identified in caper. PRACTICAL APPLICATIONS: Capparis spinosa is one of the most popular sources of different secondary metabolites of interest to consumers. The results of the present study showed that the fermentation process of the capers is highly influential on the neutral composition of the sample. The total concentrations of aroma and phenolic compounds were reduced by 66% and 78%, respectively, in response to fermentation process.

Elucidation of hulling-induced changes in the aroma and aroma-active compounds of cv. Uzun pistachio (Pistacia vera)

BACKGROUND

The purpose of this study was to define the effects of the hulling process on the aroma and aroma-active composition of cv. Uzun pistachio. Four different hulling processes, namely wet, wet-dry, dry-dry and brine, were applied. In addition, solvent-assisted flavor evaporation (SAFE), simultaneous distillation/extraction (SDE) and purge and trap (P&T) extraction methods were also tested to obtain the best representative aroma extract.

RESULTS

The results revealed that the dry-dry hulling method was the most prominent according to the aroma and aroma-active compounds, and this was especially the case with terpene compounds. The method increased the content of terpenes, pyrazines and total aroma compounds. By application of aroma extract dilution analysis (AEDA), a total of 18 compounds were detected, of which 11 were identified for the first time in the fruit of pistachio. 2,3-Dimethylpyrazine, trimethylpyrazine and 2-ethyl-3,5-dimethylpyrazine were the compounds that had the highest flavour dilution factors.

CONCLUSION

In general, the results of the present research indicated that the hulling method highly affected the overall aroma structure of pistachios. The dry-dry hulling method is therefore suggested to manufacturers to obtain better pistachios with rich and high-quality aroma. © 2019 Society of Chemical Industry.

Elucidation of Infusion-Induced Changes in the Key Odorants and Aroma Profile of Iranian Endemic Borage ( Echium amoenum) Herbal Tea

Infusion-induced changes in the aroma and key odorants and their odor activity values of Iranian endemic herbal (Gol-Gavzaban) tea obtained from shade-dried violet-blue petals of borage ( Echium amoenum) were studied for the first time. Two hot teas and one cold tea were investigated and coded as 4MN (4 min/98 °C), 16MN (16 min/98 °C), and 24HR (24 h/ambient temperature), respectively. Aromatic extracts of the tea samples were isolated by the liquid-liquid extraction method and analyzed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O) for the first time. According to the results of the aroma profiling, a total of 35 common aroma compounds comprising alcohols, acids, volatile phenols, lactones, aldehydes, ketone, pyrroles, and furans were identified and quantified in the tea samples. Indeed, it is worth noting that the aroma profiles of the borage teas were similar. However, the effects of the infusion techniques were clearly different as observed on the content of each individual and total compounds in the samples. The highest mean total concentration was detected in 24HR (266.0 mg/kg), followed by 16MN (247.1 mg/kg) and 4MN (216.1 mg/kg). 1-Penten-3-ol was the principal volatile component in all borage teas. On the basis of the result of the flavor dilution (FD) factors, a combined total of 22 different key odorants was detected. The potential key odorants with regard to FD factors in all samples were prevailingly alcohols, acids, and terpenes. The highest FD factors were observed in 2-hexanol (2048 in 4MN and 24HR; 1024 in 16MN) and 1-penten-3-ol (2048 in 24HR; 1024 in 4MN and 16MN) in samples providing herbal and green notes. Principal component analysis (PCA) showed that the tea samples could clearly be discriminated in terms of their aroma profiles and key odorants. The findings of the current study demonstrate that the tea preparation conditions have a significant impact on the organoleptic quality of borage tea.

LC-DAD-ESI-MS/MS-based phenolic profiling and antioxidant activity in Turkish cv. Nizip Yaglik olive oils from different maturity olives

The current study was designed to find out how olive maturity indices (2.5, 3.5, and 4.5) affect the individual phenolic compounds and antioxidant potencies of olive oils produced from cv. Nizip Yaglik olives. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode was utilized for the determination of phenolic composition qualitatively and quantitatively. Findings asserted a quite similar phenolic profile (14 phenols) depending on the various phenolic groups in all oils, while the concentration of total and individual phenolic compounds revealed significant differences between the samples statistically (p < 0.05). Among the individual phenolic classes in all samples, secoiridoids were the most prevailing group and their total content showed a clear significant decline as the olive fruits get ripened. Antioxidant potency values showed a clear diminution attitude during the maturation of the olives. The principal component analysis revealed that oils were discriminated from each other according to phenolic compounds and antioxidant potencies. Moreover, oils obtained from the unripe and medium-ripe fruits possessed a very good quality marked by their elevated phenolic levels.

Characterization of aroma, aroma-active compounds and fatty acids profiles of cv. Nizip Yaglik oils as affected by three maturity periods of olives

BACKGROUND

The present study aimed to investigate how olive maturity indices (MI) (2.5, 3.5 and 4.5 MI) affect the aroma, aroma-active compounds, fatty acid profiles and color properties of cv. Nizip Yaglik olive oils. Various techniques for extracting volatiles from oil materials are available in the literature. Aroma compounds were extracted by the solvent-assisted flavor evaporation extraction method for the first time in olive oil.

RESULTS

The type and number of aroma-active compounds varied according to maturity periods of olives. A total of 22, 21 and 20 different key odorants were found in aromatic extracts of samples with 2.5, 3.5 and 4.5 MI, respectively. The most potent aroma-active compounds based on flavor dilution (FD) factor values were hexanal (green) for 2.5 MI (FD: 1024) and 3.5 MI (FD: 512), as well as 1-penten-3-ol (green-leafy) for 4.5 MI (FD: 512).

CONCLUSION

Overall, olive oils obtained from unripe and medium-ripe olives had stronger green and fruity odours compared to ripe olives. Principal component analysis demonstrated that oils were clearly discriminated according to their general physicochemical analysis, fatty acids, aroma profiles and key odorants. The results of the present study show that the olive maturity period has a significant influence on the quality parameters of olive oil. © 2018 Society of Chemical Industry.