Aromatic Perspectives: An In-Depth review on Extracting, influencing Factors, and the origins of raisin aromas.

Raisins, derived from dried grapes, represent a valuable commodity rich in secondary metabolites, particularly volatile organic compounds (VOCs). The primary objective of this review is to identify the VOCs that are influencing the aromatic profile of raisins to improve consumer preferences. However, extensive research has been done to optimize grape drying methods for different raisin attributes. In the context of this review, an in-depth investigation of published literature revealed the extraction of over 120 VOCs from raisins using SPME. Furthermore, we explored factors shaping raisin aroma and the sources of VOC generation. This review aims to pinpoint research gaps and provide an opportunity for future developments in studying raisins' aroma. This involves integrating advanced analytical techniques, examining processing method impacts, and considering consumer perception to enhance the overall understanding of raisin aromas. The outcomes are anticipated to provide valuable insights for the industry and the scientific community.

Morpho-physiological growth performance and anti-oxidative capabilities of Acacia jacquemontii and Acacia nilotica upon exposure to Co3O4 Nbs in lead-contaminated soil.

Immense crowd of heavy metal in cultivated land is evolving as a global concern as a result of boosted level of soil toxicity. Amongst various metals, Lead (Pb) contamination has become alarming for plant and human heath through ingesting of polluted soils and food crops. To counterfeit this, a nanotechnological neutralizer effective in form of soiling of cobalt oxide Co3O4 Nbs to Acacia jacquemontii and Acacia nilotica with various meditations as 25, 50, 75 and 100 ppm). A Substantial result was observed on growth of plants but premium results were got by applications of cobalt oxide Nbs at 75 ppm. By this means, enhanced root length (39%), fresh weight (32%), shoot length (58%), as well as dry weight (28%) in selected Acacia species compared to control. Chlrophy contents in A. jacquemontii were estimated to be 0.23, 2.73 and 3.19 mg/L with treated with different concentrations of cobalt Nbs while in A. nilotica, the contents were 0.51, 2.93 and 3.12 mg/L respectively on same concentration. The atomic absorption (AAS), antioxidant activity and defendable positive comeback by using Co3O4 Nbs. Hence, the greenly synthesized Co3O4 Nbs counter acts lead toxicity to override and preserving the growth of plant. Such nanotechnological kits can consequently enhance the alternative system to stunned toxicity for distinguish the yield demand end to end with the progress of agronomic management approaches.

EBR and JA regulate aroma substance biosynthesis in 'Ruidu Hongyu' grapevine berries by transcriptome and metabolite combined analysis.

Volatile compounds including terpenes, aldehyde, phenol, and alcohol are significantly contributed floral and fruity aromas to the Muscat variety. 'Ruidu Hongyu' grapevine is one of the newly developed grape varieties, and cultivation of this variety has been extended across China due to unique quality traits and taste. In this study, HS-SPME/GC-MS and transcriptome sequencing analysis were performed to evaluate the impact of exogenous 2,4-epibrassinolide (EBR), jasmonic acid (JA), and their signaling inhibitors brassinazole (Brz)/sodium diethyldithiocarbamate (DIECA) on the biosynthesis of aroma substances in 'Ruidu Hongyu' grapevine. According to the results, exogenous BR and JA promoted the accumulation of various aroma substances, including hexenal, 2-hexenal, nerol oxide, vanillin, hotrienol, terpineol, neral, nerol, geraniol, and geranic acid. After EBR and JA treatments, most of the genes responsible for terpene, aldehyde, and alcohol biosynthesis expressed at a higher level than the CK group. Relatively, EBR treatment could not only promote endogenous BR biosynthesis and metabolism but also elevate BR signaling transduction. JA treatment contributed to endogenous JA and MeJA accumulation, as well. Through transcriptome sequencing, a total of 3043, 903, 1470, and 607 DEGs were identified in JA vs. JD, JA vs. CK, BR vs. CK, and BR vs. Brz, respectively. There were more DEGs under both EBR and JA treatments at late fruit ripening stages. The findings of this study increase our understanding regarding aroma substances biosynthesis and endogenous BR/JA metabolism in response to exogenous EBR and JA signals.

Preparation of Vanillin-Taurine Antioxidant Compound, Characterization, and Evaluation for Improving the Post-Harvest Quality of Litchi.

Litchi's post-harvest pericarp browning is one of the main constraints that drastically affect its visual attributes and market potential. Therefore, the vanillin-taurine Schiff base (VTSB) compound prepared from natural compounds of vanillin and taurine exhibited higher DPPH-radical-scavenging invitro antioxidant activity than vanillin. VTSB first-time report to mitigate the postharvest browning of litchi fruit. In this study, litchi fruits were dipped in 0.3 mM (based on pre-experiment) VTSB solution and stored at 25 ± 1 °C for six days to examine their effects on browning and postharvest quality. Fruit treated with VTSB had lower levels of browning degree (BD), browning index (BI), weight loss, soluble quinone (SQ), relative electrolyte leakage (REL), and malondialdehyde (MDA) than control fruit. Additionally, total anthocyanins and phenolic concentrations, Total soluble solids (TSS), and 2,2-diphenyl-1-picrylhydrazyl-free radical scavenging activity (DPPH-RSA) were preserved higher in VTSB-treated litchi fruit. The levels of Ascorbate peroxidase (APX), Superoxide dismutase (SOD), and Catalase (CAT) were higher in treated fruit, whereas polyphenol oxidase (PPO) and Peroxidase (POD) were decreased during the postharvest period. This study suggested that VTSB would be very useful for different post-harvest problems in the fruit and vegetable industry.

Bioinspired Cobalt Oxide Nanoball Synthesis, Characterization, and Their Potential as Metal Stress Absorbants.

Massive accumulation of heavy metals in agricultural land as a result of enhanced levels of toxicity in the soil is an emerging global concern. Among various metals, zinc contamination has severe effects on plant and human health through the food chain. To remove such toxicity, a nanotechnological neutralizer, cobalt oxide nanoballs (Co3O4 Nbs) were synthesized by using the extract of Cordia myxa. The Co3O4 Nbs were well characterized via UV-vis spectrophotometry, scanning electron microscopy, and X-ray diffraction techniques. Green-synthesized Co3O4 Nbs were exposed over Acacia jacquemontii and Acacia nilotica at different concentrations (25, 50, 75, and 100 ppm). Highly significant results were observed for plant growth by the application of Co3O4 Nbs at 100 ppm, thereby increasing the root length (35%), shoot length (48%), fresh weight (44%), and dry weight (40%) of the Acacia species with respect to the control. Furthermore, physiological parameters including chlorophyll contents, relative water contents, and osmolyte contents like proline and sugar showed a prominent increase. The antioxidant activity and atomic absorption supported and justified the positive response to using Co3O4 Nbs that mitigated the heavy-metal zinc stress by improving the plant growth. Hence, the biocompatible Co3O4 Nbs counteract the zinc toxicity for governing and maintaining plant growth. Such nanotechnological tools can therefore step up the cropping system and overcome toxicity to meet the productivity demand along with the development of agricultural management strategies.

Interrogating Raisin Associated Unsaturated Fatty Acid Derived Volatile Compounds Using HS-SPME with GC-MS.

This study proposed to investigate the generation mechanism of raisins-derived volatile compounds during unsaturated fatty acids oxidation (UFAO) using a mixture of fatty acids (FAs) and four individual FA at different time intervals (0, 4, 8, 12, 16, and 20 days; 60 °C). During the sun-drying of 'Thompson Seedless' grapes (Vitis vinifera L.), a total of 39 UFAO-derived volatiles were characterized by the GC-MS. Firstly a pH value of 4.2 was optimized to proceed with a raisin drying-like UFAO model reaction. Afterward, GC-MS quantification revealed 45 UFAO-derived volatiles, and the maximum numbers of compounds were identified in the interaction of all FAs (39) following linoleic acid (29), erucic acid (27), oleic acid (25), and linolenic acid (27). Pentanoic acid, (E,E)-2,4-octadienal, and n-decanoic acid were only quantified in all FAs, linoleic acid, and erucic acid, respectively. This study showed that all FAs reactions were found to be responsible for the generation of a greater number of UFAO-derived volatiles with higher concentrations.

Improving berry quality and antioxidant ability in 'Ruidu Hongyu' grapevine through preharvest exogenous 2,4-epibrassinolide, jasmonic acid and their signaling inhibitors by regulating endogenous phytohormones.

Grape berries contain a variety of metabolites, such as anthocyanins, sugars, fatty acids, and antioxidants. Endogenous phytohormones strongly influence these metabolites, which regulate berry quality improvement. In this study, we evaluated the effects of 2,4-epibrassinolide (EBR, brassinolide (BR)-like growth regulator), jasmonic acid (JA), and their signaling inhibitors brassinazole (Brz), and sodium diethyldithiocarbamate (DIECA) on berry quality and antioxidant ability. Overall, the pre-harvest application of 0.5 mg L-1 EBR and 100 µmol L-1 JA significantly influences the quality of the grape berry. Results showed that EBR was superior to other treatments at enhancing the content of different metabolites, including anthocyanins, fructose, glucose, and a variety of fatty acids, in grapes. EBR and JA also enhanced the synthesis of gibberellin3 (GA3), cytokinin (CTK), salicylic acid (SA), JA, methyl jasmonate (MeJA), BR, and abscisic acid (ABA), while inhibiting the synthesis of auxin (IAA). Most genes related to BR/JA and anthocyanins/sugars/fatty acids biosynthesis were up-regulated. The effects of Brz and DIECA on the grape berry quality were totally reversed throughout the study, as shown by EBR and JA. According to correlation analysis, EBR and JA have a beneficial positive interaction that promotes the formation of strong coherences in grape berries between ABA/IAA/ZT-fruit expansion, BR/JA/MeJA/GA3/ZR-biochemical characteristics development, JA/MeJA/ABA/GA3/SA/ZR-antioxidant capacity enhancement, and JA/MeJA/IAA/GA3/ZT/ZR-fatty acids accumulation. In this regard, we concluded that preharvest exogenous 0.5 mg L-1 EBR and 100 µmol L-1 JA is a successful way to improve grape berry quality.

Recent advances in self-assembly behaviors of prolamins and their applications as functional delivery vehicles.

Prolamins are a group of storage proteins (zeins, kafirins, hordeins, secalins, gliadins, glutenins, and avenins) found in the endosperm of cereal grains and characterized by high glutamine and proline content. With the high proportion of nonpolar amino acids (40-80%) and peculiar solubility (alcohol (60-90%), acetic acid, and alkaline solutions), prolamins exhibit tunable self-assembly behaviors. In recent years, research practices of utilizing prolamins as green building materials of functional delivery vehicles to improve the health benefits of bioactive compounds have surged due to their attractive advantages (e.g. sustainability, biocompatibility, fabrication potential, and cost-competitiveness). This article covers the recent advances in self-assembly behaviors leading to the fabrication of nanoparticles, fibers, and films in the bulk water phase, at the air-liquid interface, and under the electrostatic field. Different fabrication methods, including antisolvent precipitation, evaporation induced self-assembly, thermal treatment, pH-modulation, electrospinning, and solvent casting for assembling nanoarchitectures as functional delivery vehicles are highlighted. Emerging industrial applications by mapping patents, including encapsulation and delivery of bioactive compounds and probiotics, active packaging, Pickering emulsions, and as functional additives to develop safer, healthier, and sustainable food products are discussed. A future perspective concerning the fabrication of prolamins as advanced materials to promote their commercial food applications is proposed.

Engineering Emulsion Gels as Functional Colloids Emphasizing Food Applications: A Review.

Gels are functional materials with well-defined structures (three-dimensional networks) assembled from the dispersed colloids, and capable of containing a large amount of water, oil, or air (by replacing the liquid within the gel pores), known as a hydrogel, oleogel, and aerogel, respectively. An emulsion gel is a gelled matrix filled with emulsion dispersion in which at least one phase, either continuous phase or dispersed phase forms spatial networks leading to the formation of a semisolid texture. Recently, the interest in the application of gels as functional colloids has attracted great attention in the food industry due to their tunable morphology and microstructure, promising physicochemical, mechanical, and functional properties, and superior stability, as well as controlled release, features for the encapsulated bioactive compounds. This article covers recent research progress on functional colloids (emulsion gels), including their fabrication, classification (protein-, polysaccharide-, and mixed emulsion gels), and properties specifically those related to the gel-body interactions (texture perception, digestion, and absorption), and industrial applications. The emerging applications, including encapsulation and controlled release, texture design and modification, fat replacement, and probiotics delivery are summarized. A summary of future perspectives to promote emulsion gels' use as functional colloids and delivery systems for scouting potential new applications in the food industry is also proposed. Emulsion gels are promising colloids being used to tailor breakdown behavior and sensory perception of food, as well as for the processing, transportation, and targeted release of food additives, functional ingredients, and bioactive substances with flexibility in designing structural and functional parameters.

Comparative fungal diversity and dynamics in plant compartments at different developmental stages under root-zone restricted grapevines.

BACKGROUND: The root-zone restriction cultivation technique is used to achieve superior fruit quality at the cost of limited vegetative and enhanced reproductive development of grapevines. Fungal interactions and diversity in grapevines are well established; however, our knowledge about fungal diversity under the root-zone restriction technique is still unexplored. To provide insights into the role of mycobiota in the regulation of growth and fruit quality of grapevine under root-zone restriction, DNA from rhizosphere and plant compartments, including white roots (new roots), leaves, flowers, and berries of root-zone restricted (treatment) and conventionally grown plants (control), was extracted at three growth stages (full bloom, veraison, and maturity). RESULTS: Diversity analysis based on the ITS1 region was performed using QIIME2. We observed that the root-zone restriction technique primarily affected the fungal communities of the soil and plant compartments at different growth stages. Interestingly, Fusarium, Ilyonectria, Cladosporium and Aspergillus spp observed in the rhizosphere overlapped with the phyllosphere at all phenological stages, having distinctive abundance in grapevine habitats. Peak richness and diversity were observed in the rhizosphere at the full bloom stage of control plants, white roots at the veraison stage of treatment, leaves at the maturity stage of treatment, flowers at the full bloom stage and berries at the veraison stage of control plants. Except for white roots, the diversity of soil and plant compartments of treated plants tended to increase until maturity. At the maturity stage of the treated and control plants, the abundance of Aspergillus spp. was 25.99 and 29.48%, respectively. Moreover, the total soluble sugar content of berries was 19.03 obrix and 16 obrix in treated and control plants, respectively, at the maturity stage. CONCLUSIONS: This is the first elucidative study targeting the fungal diversity of conventional and root-restricted cultivation techniques in a single vineyard. Species richness and diversity are affected by stressful cultivation known as root zone restriction. There is an association between the abundance of Aspergillus spp. and fruit quality because despite causing stress to the grapevine, superior quality of fruit is retrieved in root-zone restricted plants.

Drying Treatments Change the Composition of Aromatic Compounds from Fresh to Dried Centennial Seedless Grapes.

Raisin aroma is a vital sensory characteristic that determines consumers' acceptance. Volatile organic compounds (VOCs) in fresh grapes, air-dried (AD), pre-treated air-dried (PAD), sun-dried (SD), and pre-treated sun-dried (PSD) raisins were analyzed, with 99 and 77 free- and bound-form compounds identified in centennial seedless grapes, respectively. The hexenal, (E)-2-hexenal, 1-hexanol, ethyl alcohol, and ethyl acetate in free-form while benzyl alcohol, ß-damascenone, gerenic acid in bound-form were the leading compounds. Overall, the concentration of aldehydes, alcohols, esters, acids, terpenoids, ketones, benzene, and phenols were abundant in fresh grapes but pyrazine and furan were identified in raisin. Out of 99 VOCs, 30 compounds had an odour active value above 1. The intensity of green, floral, and fruity aromas were quite higher in fresh grapes followed by AD-raisins, PAD-raisins, SD-raisins, and PSD-raisins. The intense roasted aroma was found in SD-raisins due to 2,6-diethylpyrazine and 3-ethyl-2,5-dimethylpyrazine. Among raisins, the concentration of unsaturated fatty acid oxidized and Maillard reaction volatiles were higher in SD-raisins and mainly contributed green, fruity and floral, and roasted aromas, respectively.

The role of VvMYBA2r and VvMYBA2w alleles of the MYBA2 locus in the regulation of anthocyanin biosynthesis for molecular breeding of grape (Vitis spp.) skin coloration.

In grape, MYBA1 and MYBA2 at the colour locus are the major genetic determinants of grape skin colour, and the mutation of two functional genes (VvMYBA1 and VvMYBA2) from these loci leads to white skin colour. This study aimed to elucidate the regulation of grape berry coloration by isolating and characterizing VvMYBA2w and VvMYBA2r alleles. The overexpression of VvMYBA2r up-regulated the expression of anthocyanin biosynthetic genes and resulted in higher anthocyanin accumulation in transgenic tobacco than wild-type (WT) plants, especially in flowers. However, the ectopic expression of VvMYBA2w inactivated the expression of anthocyanin biosynthetic genes and could not cause obvious phenotypic modulation in transgenic tobacco. Unlike in VvMYBA2r, CA dinucleotide deletion shortened the C-terminal transactivation region and disrupted the transcriptional activation activity of VvMYBA2w. The results indicated that VvMYBA2r positively regulated anthocyanin biosynthesis by forming the VvMYBA2r-VvMYCA1-VvWDR1 complex, and VvWDR1 enhanced anthocyanin accumulation by interacting with the VvMYBA2r-VvMYCA1 complex; however, R44 L substitution abolished the interaction of VvMYBA2w with VvMYCA1. Meanwhile, both R44 L substitution and CA dinucleotide deletion seriously affected the efficacy of VvMYBA2w to regulate anthocyanin biosynthesis, and the two non-synonymous mutations were additive in their effects. Investigation of the colour density and MYB haplotypes of 213 grape germplasms revealed that dark-skinned varieties tended to contain HapC-N and HapE2, whereas red-skinned varieties contained high frequencies of HapB and HapC-Rs. Regarding ploidy, the higher the number of functional alleles present in a variety, the darker was the skin colour. In summary, this study provides insight into the roles of VvMYBA2r and VvMYBA2w alleles and lays the foundation for the molecular breeding of grape varieties with different skin colour.

Small RNA Sequencing Analysis of miRNA Expression Reveals Novel Insihts into Root Formation under Root Restriction Cultivation in Grapevine (Vitis vinifera L.).

Root restriction cultivation (RRC) can influence plant root architecture, but its root phenotypic changes and molecular mechanisms are still unknown. In this study, phenotype observations of grapevine root under RRC and control cultivation (nRC) at 12 time points were conducted, and the root phenotype showed an increase of adventitious and lateral root numbers and root tip degeneration after RRC cultivation from 70 days after planting (DAP). The 70 and 125 DAP sampling of two different cultivations, named nR70, RR70, nR125, and RR125, were selected for small RNA sequencing. A total of 153 known miRNAs and 119 predicted novel miRNAs were obtained. Furthermore, BLAST was used to predict the novel miRNAs with miRBase databases using the default parameters; 96 of the 119 predicted novel miRNAs were similar to other species, and the remaining 23 grapevine-specific novel miRNAs were obtained. There were 26, 33, 26, and 32 miRNAs that were differentially expressed in different comparison groups (RR70 vs. nR70, RR125 vs. nR125, nR125 vs. nR70 and RR125 vs. RR70). Target genes prediction of differentially expressed miRNAs was annotated on a variety of biological processes, and 24 participated in root development. Moreover, multiple miRNAs were found to jointly regulate lateral root development under root restriction conditions. The miRNA expression pattern comparison between RRC and nRC may provide a framework for the future analysis of miRNAs associated with root development in grapevine.

Impact of Drying Method on the Evaluation of Fatty Acids and Their Derived Volatile Compounds in 'Thompson Seedless' Raisins.

Air- and sun-dried raisins from Thompson Seedless (TS) grapes were analyzed under GC/MS to evaluate fatty acids (FAs) and their derived volatile compounds, coming from unsaturated fatty acids oxidation. A total of 16 FAs were identified in TS raisins, including 10 saturated fatty acids (SFAs) and 6 unsaturated fatty acids (USFAs). The contents of C18:0, C15:0, and C16:0 among SFAs and C18:3, C18:2 and C18:1 in USFAs were significantly higher. Furthermore, USFAs such as C16:1 and C20:1 were only identified in air-dried raisins. The principal component analysis showed the increased content of FAs and FA-derived compounds were in air-dried and sun-dried raisins, respectively. Among FA-derived compounds, 2-pentyl furan, 3-octen-2-one, 1-hexanol and heptanoic acid were more potent. This study shows that air-drying is more favorable for the production of fatty acids (SFAs and USFAs), whereas sun-drying is more advantageous in terms of fatty acid-derived volatiles.

Post-storage changes of volatile compounds in air- and sun-dried raisins with different packaging materials using HS-SPME with GC/MS.

Free- and bound-form volatiles in sun-dried raisins (SDRs) and air-dried raisins (ADRs) of 'Thompson Seedless' were analyzed by gas chromatography-mass spectrometry (GC/MS) for 0, 3, 6, 9 and 12 months of storage. The compounds originating from glycosidically bound (GB) volatiles were significantly more abundant in bound-form than their free-form. A total of 89 and 88 free-form compounds were identified in ADRs and SDRs, respectively. Overall, higher concentration of unsaturated fatty-acid-oxidation (UFAO) and Maillard reaction (MR) compounds were observed in the SDRs. The plastic and woven bags have an insignificant effect on the volatiles in the raisins. The main characteristics of ADR aroma were floral and fruity, while fatty, roasted, and chemical aromas were prominent in SDRs. With the exception of chemical aroma, the aromatic series (fruity, floral, herbaceous and roasted) increased during the storage duration and become more compelling in 12 month. The packaging materials have similar effect on aromatic series, except fruity note, which was higher in woven bag. The main floral and fruity aroma contributors were decanal, ß-ionone, ethyl hexanoate, ß-damascenone, and 1-octen-3-ol. Herein we identified UFAO and MR compounds as the main contributors of raisin aromas.

Changes of free-form volatile compounds in pre-treated raisins with different packaging materials during storage.

The aroma profiles of volatile compounds (VOCs) were analyzed by GC/MS in pre-treated air-dried (PAD) and sun-dried (PSD) raisins during storage. Total 98, 94 and 81 VOCs were identified in Zixiang Seedless raisins (ZSRs), Centennial Seedless raisins (CSRs) and Thompson Seedless raisins (TSRs), respectively. During storage, the overall concentrations of VOCs of PSD raisins were higher in plastic bag (PB) compared to those in woven bag (WB). Regarding fruity and floral aromas, the effect of PAD and PB was significant throughout the storage periods (3, 6 and 9 months), however, fatty aroma was higher in PSD raisins due to the major contribution of 2,3-butanedione. The main fruity and floral aroma contributors were ß-damascenone, limonene, rose oxide, geraniol and ethyl hexanoate. This study showed that compounds came from unsaturated fatty acid oxidation, glycosidically-derived and grape-derived source were contributed to fruity, floral or herbaceous aromas, but Maillard reaction-derived VOCs imparted fatty and roasted aromas.

Free and glycosidically bound volatile compounds in sun-dried raisins made from different fragrance intensities grape varieties using a validated HS-SPME with GC-MS method.

The conditions of sample pretreatments and HS-SPME for extracting volatile compounds from raisins were optimized, and the method was validated in the study. Free and glycosidically bound volatile compounds in three different fragrance intensities raisins were analysed using this method. There were 91 compounds identified, and 72, 26 and 8 of these compounds came from fresh grapes, the auto-oxidation of unsaturated fatty acids (UFAO) and the Maillard reaction, respectively. The aroma profiles of Thompson Seedless raisins (TSRs) and Centennial Seedless raisins (CSRs) were similar, while the floral, fruity, green and roasted aromas of CSRs were higher than those of TSRs due to the contributions of benzeneacetaldehyde, 2-pentylfuran, (E)-2-nonenal and 3-ethyl-2,5-dimethyl pyrazine. Decanal, rose oxide, geraniol, linalool and ß-damascenone made the floral and fruity aromas of Zixiang Seedless raisins (ZSRs) greater than those in TSRs and CSRs, but the green and roasted aroma intensities of ZSRs were lower.