Bioconversion of Glycosidic Precursors from Sour Guava (Psidium friedrichsthalianum Nied.) Fruit by the Oral Microbiota into Odor-Active Volatile Compounds.

The ability of the human oral microbiota to hydrolyze the glycosidic aroma precursor extract isolated from sour guava (Psidium friedrichsthalianum Nied.) fruits was studied herein. The glycosidic extract (GP) was incubated with a mixture of the oral microbiota isolated from three individuals' saliva to evaluate the hydrolytic capacity of oral bacteria in the generation of odor-active compounds. The oral microbiota was able to release 1-hexanol from GP, under both aerobic and anaerobic conditions. Additionally, the aroma precursor extracts showed a decrease in the growth of harmful oral bacteria (Streptococcus and Actinomyces). This effect can be considered beneficial to human health because these bacteria have been related to different diseases of the bucco-respiratory tract.

Analysis of Phenolic Composition of Byproducts (Seeds and Peels) of Avocado (Persea americana Mill.) Cultivated in Colombia.

The byproducts (seeds and peels) of an avocado cultivated in the south of Colombia were extracted with aqueous acetone and their antioxidant properties were measured with ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays, and total polyphenol content was determined by Folin-Ciocalteu method. A bioguided fractionation was performed, first by SPE (solid phase extraction) on Amberlite XAD-7, and then by size exclusion chromatography on Sephadex LH-20. The polyphenolic-rich extracts and their fractions were analyzed by ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS), finding the presence of organic acids, hydroxycinnamic acids, catechins, free and glycosylated flavonoids, and dimeric and trimeric procyanidins. Catechin, epicatechin, six quercetin derivatives, four dimeric procyanidins (three type B and one type A), and three trimeric procyanidins (two type B and one type A) were detected in the most active fractions of avocado peel and seeds. The most antioxidant fractions contain the higher molecular weight phenolic compounds (condensed tannins).

(1R,2S,6R)-Papayanal: a new male-specific volatile compound released by the guava weevil Conotrachelus psidii (Coleoptera: Curculionidae).

The guava weevil, Conotrachelus psidii is an aggressive pest of guava (Psidium guajava L.) that causes irreparable damages inside the fruit. The volatile compounds of male and female insects were separately collected by headspace solid-phase microextraction or with dynamic headspace collection on a polymer sorbent, and comparatively analyzed by GC-MS. (1R,2S,6R)-2-Hydroxymethyl-2,6-dimethyl-3-oxabicyclo[4.2.0]octane (papayanol), and (1R,2S,6R)-2,6-dimethyl-3-oxabicyclo[4.2.0]octane-2-carbaldehyde (papayanal) were identified (ratio of 9:1, respectively) as male-specific guava weevil volatiles. Papayanal structure was confirmed by comparison of spectroscopic (EIMS) and chromatographic (retention time) data with those of the synthetic pure compound. The behavioral response of the above-mentioned compounds was studied in a Y-tube olfactometer bioassay, and their role as aggregation pheromone candidate components was suggested in this species.

Targeted Metabolomic Analysis of Polyphenols with Antioxidant Activity in Sour Guava (Psidium friedrichsthalianum Nied.) Fruit.

Psidium is a genus of tropical bushes belonging to the Myrtaceae family distributed in Central and South America. The polar extract of Psidium friedrichsthalianum Nied. was partitioned with ethyl ether, ethyl acetate, and n-butanol, and the total phenolic content and antioxidant activity were measured by Folin-Ciocalteu and ABTS assays, respectively. The ethyl acetate fraction exhibited both the highest phenolic content and antioxidant activity. Due to the complexity of this fraction, an analytical method for the comprehensive profiling of phenolic compounds was done by UPLC-ESI/QqQ in MRM (multiple reaction monitoring) mode. In this targeted analysis, 22 phenolic compounds were identified, among which several hydroxybenzoic, phenylacetic, and hydroxycinnamic acid derivatives were found. This is the first time that (+)-catechin, procyanidin B1, procyanidin B2, and (-)-epicatechin have been reported as constituents of sour guava. A fractionation by exclusion size, C18-column chromatography, and preparative RRLC (rapid resolution liquid chromatography) allowed us to confirm the presence of ellagic acid and isomeric procyanidins B, well-known bioactive compounds. The content of phenolic compounds in this fruit shows its potential for the development of functional foods.

Chemical Studies of Yellow Tamarillo (Solanum betaceum Cav.) Fruit Flavor by Using a Molecular Sensory Approach.

The odor-active volatile compounds of yellow tamarillo fruit (S. betaceum Cav.) were identified and quantified by using a sensomics approach, combining a gentle volatile extraction (solvent-assisted flavor evaporation (SAFE)), gas chromatography-mass spectrometry (GC-MS), and sensory analyses (gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA)). The medium-term purpose of this work is to evaluate the change of odor-active volatiles during processing. Thus, (Z)-3-hexenal, hexanal, and ethyl butanoate were identified as key aroma compounds of yellow tamarillo. The C6-aliphatic compounds, aliphatic esters, and terpenols were characterized as the volatiles responsible for the herbal-green, fruity, and fresh-mint odor notes of this variety, respectively. Additionally, one non-volatile compound contributing to the residual bitter taste of this fruit was isolated by a bioguided (taste sensory analyses) fractionation. The freeze-dried fruit was sequentially liquid-liquid partitioned with solvents of different polarity, and then the ethyl acetate fraction was submitted to size exclusion chromatography. Then, its structure was elucidated as rosmarinic acid, by using common spectroscopic methods (mass spectrometry (MS) and nuclear magnetic resonance (NMR)). The amount of rosmarinic acid was quantified as 46.17 ± 1.20 mg/100 g of dried fruit, by the external standard method. Its bitter taste threshold value was determined by using the 3AFC (alternative forced choice) method to be 37.00 ± 1.25 mg/L.

Characterization and bioaccessibility assessment of bioactive compounds from camu-camu (Myrciaria dubia) powders and their food applications.

Camu-camu (Myrciaria dubia) is a tropical fruit known for its content of bioactive compounds. This study aimed to evaluate physicochemically, morphologically, andsensorialpowders from camu-camu obtained by spray-drying at two inlet temperatures (150 °C and 180 °C) with three encapsulating agents (maltodextrin, whey protein and a 50:50 mixture of both) and by freeze-drying of whole fruit. The use of maltodextrin protected bet anthocyanins (cyanidin-3-glucoside (C3G) and delphinidin-3-glucoside (D3G)), but whey protein showed a better protective effect on ascorbic and malic acids. These facts were confirmed during the storage stability test, finding that relative humidity is a critical variable in preserving the bioactive compounds of camu-camu powders. The powders with the highest content of bioactive compounds were added to a yogurt and a white grape juice, and then sensory evaluated. The bioaccessibility studies in gastric and intestinal phases showed better recovery percentages of bioactive compounds in camu-camu powders (up to 60.8 %) and beverages (up to 90 %) for C3G, D3G, ascorbic acid, and malic acid than in the fruit juice. Dehydration of camu-camu (M. dubia) is a strategy to increase the bioactive compounds stability, modulate the fruit sensory properties, and improve their bioavailability after incorporation in food matrices.

Peach Palm Fruit (Bactris gasipaes) Peel: A Source of Provitamin A Carotenoids to Develop Emulsion-Based Delivery Systems.

The peach palm fruit (Bactris gasipaes) peel is a byproduct after fruit consumption. The peel flour of two varieties (yellow and red) was separately obtained by hot air drying and was subsequently milled. The proximate analysis showed that the red variety exhibited higher protein, fat, and fiber contents than the yellow one. A higher carotenoid (836.5 ± 24.5 µg/g), phenolic compounds (83.17 ± 1.76 mg GAE/100 g), and provitamin A activity (33.10 ± 0.83 µg retinol/g) were found in the cooked red variety. The carotenoid and phenolic compositions were analyzed by HPLC-PDA-MS, finding ß-carotene and γ-carotene to be major compounds. The effect of thermal treatment increased the amount of these provitamin A carotenoids and lycopene, which were detected only in the red variety. Among phenolic compounds, procyanidin dimer (isomer I), feruloyl quinic acid, and several apigenin C-hexosides were identified as major constituents of peach palm epicarp. A carotenoid-rich emulsion-based delivery system was obtained after the optimization (RSM model) of carotenoid extraction with ultraturrax and sunflower oil and further development of an ultrasound-assisted emulsion. The best conditions for a stable emulsion were 73.75% water, 25% carotenoid-rich oil extract, 1.25% emulsifiers, and 480 W of ultrasonic power for 5 min. The optimized emulsion had a total carotenoid content of 67.61 µg/g, Provitamin A activity of 3.23 ± 0.56 µg RAE/g, droplet size of 502.23 nm, polydispersity index of 0.170, and zeta potential of -32.26 mV. This emulsion was chemically and physically stable for 35 days at 30 ± 2 °C, showing potential as a food additive with biofunctional properties. The strategy here developed is an economical and environmentally friendly process that allows the reuse of the byproduct of B. gasipaes.

Camu Camu (Myrciaria dubia (Kunth) McVaugh): An Amazonian Fruit with Biofunctional Properties-A Review.

Amazonian Camu camu fruit (Myrciaria dubia (Kunth) McVaugh) has been called a "superfruit" due to its high levels of bioactive and antioxidant compounds such as polyphenols, carotenoids, and vitamin C. The biofunctional properties of camu camu fruit (including pulp, peel, and seeds) have been well established through several in vitro and in vivo studies. Several reports confirmed the nutritious and biofunctional value of camu camu extracts or its food-derived products, exhibiting antioxidant, antihyperglycemic, antihypertensive, and antiobesity activity, contributing to quality life improvement. Other studies showed antimicrobial, anti-inflammatory, antiproliferative, antihepatotoxic, antihemolytic, antimutagenic, and cell rejuvenation bioactivities. This Review summarizes the bioactive profile of camu camu fruit through the understanding of some physiological modulation processes and its contribution to the Amazon bioeconomy under the development of biofunctional food ingredients exhibiting health benefits.

Semiochemicals Associated with the Western Flower Thrips Attraction: A Systematic Literature Review and Meta-Analysis.

The study of the semiochemicals of the western flower thrips (WFT), Frankliniella occidentalis, Pergande (Thysanoptera: Thripidae), is a relevant topic that spans the last two decades. Approximately a hundred articles published on this subject from 2000 to 2022 can be found in academic databases, representing approximately 5% of the research on this important pest. These topics have generated a platform for novel research with a high potential for development. However, to move on to a new research step, an effectiveness evaluation of the compounds discovered so far is necessary. This review conducted a systematic analysis of the research focused on the semiochemicals (kairomones, pheromones, and attractants) for this pest. Papers from the past three decades on WFT attraction to semiochemicals were collected from databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The number of individuals attracted to compounds was extracted from the papers and compiled for analysis. With this information, an attraction ratio was calculated. Forty-one possible attractants were found in the literature, with methyl isonicotinate being the most-studied compound so far, with the third-highest attraction ratio. δ-Decalactone was the compound with the highest attraction ratio, but it was one of the least studied. A meta-analysis of the WFT choosing proportion was performed for the compounds with more trials found in the literature. The predicted mean choice percentages for methyl isonicotinate (MIN) and Lurem-TR, the MIN's commercial product, were 76.6% and 66.6%, respectively. There was a convergence among the analyzed studies showing a high degree of research focus on the same group of nitrogen-containing compounds (mainly the pyridine structure). These findings call for future research to diversify the discovery and evaluation of attractive compounds in this relevant study area.

Effect of temperature and particle size on physicochemical and techno-functional properties of peach palm peel flour (Bactris gasipaes, red and yellow ecotypes).

In this study, the effect of temperature and particle size on the techno-functional properties of the flour from peach palm fruit peels (Bactris gasipaes, red and yellow ecotype) were evaluated. The flour from peach palm epicarp obtained by natural convective drying was physicochemically characterized, including the assessment of total dietary fiber determined under the gravimetric enzymatic method. The results obtained showed that temperature and particle size present a significant effect (p < 0.001) on techno-functional properties except for swelling capacity. The flour from the red ecotype presented better nutritional: total dietary fiber 47.93 ± 1.72%, protein 6.87 ± 0.15% and techno-functional properties: water retention capacity (WRC) 7.13 ± 0.29 g/g, oil retention capacity (ORC) 6.24 ± 0.08 g/g, emulsifier activity (EA) 56.84 ± 0.28%, emulsifier stability (ES) 50.33 ± 0.31% than the yellow one water absorption capacity (WAC) 5.31 ± 0.03 g/g and water solubility (WS) 59.58 ± 0.04% at 60 °C and 0.25 mm. Therefore, this study showed that the flour obtained from peach palm fruit peels contains high fiber and protein values and could be used as a promising natural additive (source of dietary fiber or emulsifier) for the food industry.

Mono-n-butyl Malate-Derived Compounds from Camu-camu (Myrciaria dubia) Malic Acid: The Alkyl-Dependent Antihyperglycemic-Related Activity.

Malic acid derivatives from camu-camu (Myrciaria dubia) fruit exhibited a strong in vitro inhibitory activity toward pancreatic α-amylase and α-glucosidase enzymes. During a bioguided chromatographic fractionation process of the whole fruit (pulp and peelings) polar extract, isomers (S)-4-butoxy-2-hydroxy-4-oxobutanoic acid (1) and (S)-4-butoxy-3-hydroxy-4-oxobutanoic acid (2) (84:16) were isolated and identified as a potent inhibitor of α-amylase (IC50= 11.69 ± 1.75 µg/mL) and α-glucosidase (IC50 = 102.69 ± 4.16 µg/mL). The chemical structures were confirmed by HPLC-ESIMS and 1H and 13C NMR (one- and two-dimensional) analyses. The structure-based virtual screening demonstrated that the aliphatic moiety plays a significant role in the binding mode of the test alkyl malate esters. Compound 1 exhibited the best interaction profile to bind both enzymes, having key structural features to form relevant contacts by involving adequate enzyme-ligand complex stabilization and compactness over time.

Chemical and sensory evaluation of cold brew coffees using different roasting profiles and brewing methods.

This study evaluated the effects of different roasting profiles (time/temperature) and brewing methods on the physicochemical and sensory characteristics of coffee brews. Cold brewing (dripping and immersion) and hot brewing (French press) methods were studied to understand the effects of water temperature and technical brewing method conditions on the chemical compound extraction in coffees roasted at high-temperature short time (HTST) and low-temperature long time (LTLT). The results showed that coffee beverages were clearly differentiated concerning the roasting profile when hot water was used (90 ± 3 °C) in brewing. Separation of beverages according to the water temperature used in brewing was observed. Notably, hot brewing coffees were distinguished from cold brewing (19 ± 2 °C) based on a higher titratable acidity and abundance of some furan compounds. The non-volatile extraction rate increased at higher brewing temperatures. At the same brewing temperature, dripping exhibited a higher extraction rate than immersion brewing, which suggests that the coffee extraction process is affected by the design and operation of the cold brewing system. Coffee beverages brewed with HTST and cold dripping displayed the highest value in total dissolved solids (TDS), extraction yield, as well as the highest caffeine, trigonelline, 4- and 5-caffeoylquinic acids (CQAs) contents. Regardless of the roasting profile, coffees brewed by cold dripping were perceived with more bitter and roasted flavors. In contrast, cold immersion and hot coffee beverages showed remarkable sweetness, nutty, caramel, and malt attributes. In turn, these attributes showed an inverse correlation with caffeine concentration, trigonelline, CQAs, and TDS. The findings of this study demonstrate that volatile and non-volatile compounds present in roasted coffee depend on time-temperature roasting conditions; in turn, their presence in the resulting beverages are related to the extraction of the operational conditions of coffee brewing methods.

Chemical characteristics and colorimetric properties of non-centrifugal cane sugar ("panela") obtained via different processing technologies.

Non-centrifugal cane sugar (NCS) samples obtained by traditional moulding and granulation, and also via a novel spray-drying powdering process without additives, were assessed to characterise their sugar and phenolic profiles, flavonoid content, as well as colour parameters. As expected, sucrose was the predominant sugar (91.9-95.5%), followed by glucose (2.9-4.6%), and fructose (1.6-3.7%). Total phenolic content was between 0.4 and 0.6% and total flavonoid content into the range of 0.2-0.4%. Six phenolic acids were found in all NCS samples: protocatechuic acid (0.36-0.94 µg/100 g), vanillic acid (0.70-1.45 µg/100 g), chlorogenic acid (2.08-3.82 µg/100 g), syringic acid (1.08-2.80 µg/100 g), p-coumaric acid (0.69-1.35 µg/100 g), and ferulic acid (0.50-0.95 µg/100 g). The thermal treatment under high temperatures required in the production of granulated products was related with darker colours and changes in phenol and flavonoid contents. In contrast, spray drying generates clearer products, but with slightly less phenol and flavonoid contents.

Changing the Landscape: An Introduction to the Agricultural and Food Chemistry Technical Program at the 258th American Chemical Society National Meeting in San Diego.

This special issue of the Journal of Agricultural and Food Chemistry (JAFC) is a highlight of the Agricultural and Food Chemistry Division (AGFD) technical program at the 258th National Meeting of the American Chemical Society (ACS) in San Diego, CA, U.S.A., on August 25-29, 2019. At the conference, AGFD had 44 oral sessions at 19 symposia and 100 poster presentations with more than 400 abstract submissions. The technical program covered a broad range of current research and development topics in agricultural and food chemistry, including bioactive food components, diet and human nutrition, utilization of agricultural materials in food systems, food packaging, nanotechnology, and food safety, as well as several special award symposia. This is the first JAFC special issue that highlights an ACS national meeting program with joint efforts from AGFD.

Advances in Health-Promoting Food Ingredients.

As part of the 256th American Chemical Society National Meeting that was held in Boston, MA, U.S.A., in August 2018, the symposium on "Health-Promoting Food Ingredients" was organized in collaboration with Dr. Agnes Rimando (rest in peace). This symposium aimed to present the latest advances related to food ingredients (e.g., pure compounds, extracts, or additives) that potentially confer health benefits and reduce the development of lifestyle-related metabolic disorders (e.g., hypertension, obesity, cardiovascular diseases, and diabetes, among others). The studies presented included the evaluation of functional properties of bioactive compounds commonly found in foods, with an emphasis in (poly)phenols (anthocyanins, flavonols, and proanthocyanidins), and dietary fiber and their interaction with gut microbiota. Many studies were focused on whole extracts of foods and the bioactivity measured in vivo at the cellular level. The role of (poly)phenols in the prevention of cardiovascular diseases and type 2 diabetes was highlighted.

Effect of grinding, extraction time and type of coffee on the physicochemical and flavour characteristics of cold brew coffee.

The effects of grinding (medium-coarse) and extraction time (14-22 h) on the physicochemical and sensorial properties of cold brew coffee produced using two types of Colombian specialty coffees (Huila and Nariño) were evaluated. Cold coffee brewed under coarse grinding and 22 h of extraction exhibited the highest values of total dissolved solids, extraction yield, pH, titratable acidity (TA), and total phenolic content. The type of coffee used mainly affected the TA and pH. All cold brew coffee samples had lower TA values than their hot counterparts. Nariño cold brew samples had higher TA values than those of Huila in all treatments evaluated. Higher scores were reported in the sensorial evaluation of cold brew coffee when prepared using the shortest time (14 h) and coarse grinding for both coffee types. These coffees were characterized by strong sweetness, fruity and floral flavours, medium bitterness and acidity, and a creamy body. Furans, pyrazines, ketones, aldehydes, pyrroles, esters, lactones, furanones, and phenols were detected as odour-active compounds. The findings of this study demonstrate that the particle size, contact time, and coffee type affect the physicochemical and sensorial characteristics of cold brew coffee, leading to cold brew coffees with different flavour profiles.

Ent-3,4-seco-labdane and ent-labdane diterpenoids from Croton stipuliformis (Euphorbiaceae).

From a methanolic extract of the leaves of Croton stipuliformis, three ent-3,4-seco-labdanes (1-3) and an ent-labdane (4) together with the known compounds 6-hydroxynidorellol (5), maravuic acid, and sitosterol were isolated and identified from their spectroscopic data. The absolute stereochemistry of compound 4 was determined by application of Mosher's method in the NMR tube.

Characterization of the aroma-active compounds in pink guava (Psidium guajava, L.) by application of the aroma extract dilution analysis.

The volatiles present in fresh, pink-fleshed Colombian guavas ( Psidium guajava, L.), variety regional rojo, were carefully isolated by solvent extraction followed by solvent-assisted flavor evaporation, and the aroma-active areas in the gas chromatogram were screened by application of the aroma extract dilution analysis. The results of the identification experiments in combination with the FD factors revealed 4-methoxy-2,5-dimethyl-3(2 H)-furanone, 4-hydroxy-2,5-dimethyl-3(2 H)-furanone, 3-sulfanylhexyl acetate, and 3-sulfanyl-1-hexanol followed by 3-hydroxy-4,5-dimethyl-2(5 H)-furanone, ( Z)-3-hexenal, trans-4,5-epoxy-( E)-2-decenal, cinnamyl alcohol, ethyl butanoate, hexanal, methional, and cinnamyl acetate as important aroma contributors. Enantioselective gas chromatography revealed an enantiomeric distribution close to the racemate in 3-sulfanylhexyl acetate as well as in 3-sulfanyl-1-hexanol. In addition, two fruity smelling diastereomeric methyl 2-hydroxy-3-methylpentanoates were identified as the ( R,S)- and the ( S,S)-isomers, whereas the ( S,R)- and ( R,R)-isomers were absent. Seven odorants were identified for the first time in guavas, among them 3-sulfanylhexyl acetate, 3-sulfanyl-1-hexanol, 3-hydroxy-4,5-dimethyl-2(5 H)-furanone, trans-4,5-epoxy-( E)-2-decenal, and methional were the most odor-active.