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Sugar composition not only affects fruit flavor but is also an important determinant of fruit taste and consumer preference. In this study, changes in the sugar content and sugar-metabolizing enzymes were investigated from different sections of various fruit development phases of ‘Hongshuijing’ pitaya (Hylocereus monacanthus). Genes related to sugar metabolism were also screened by transcriptome analyses. The results indicated that glucose was the major sugar in mature pitaya fruit, and was mainly regulated by vacuolar acid invertase (VAI) and sucrose synthase (SS) (degradative direction). Sugar accumulation varied in pulp between different sections of the pitaya fruit. VAI, neutral invertase (NI) and SS (degradative direction) are crucial enzymes for sugar accumulation in pitaya. The expression of 17 genes related to sucrose metabolism and obtained from seven databases [NCBI non-redundant protein database (Nr), NCBI non-redundant nucleotide sequence database (Nt), EuKaryotic Orthologous Groups (KOG), The Protein Families (Pfam), Kyoto Encyclopedia of Genes and Genomes (KEGG), Swiss-prot, and Gene Ontology (GO)] were analyzed in different pitaya pulp sections. HpVAI1 had the highest relative expression level on the 29th day after pollination (DAP). Positive correlations were found between HpVAI1 expression and VAI activity; HpNI4 and NI activity; HpSS2, HpSS5, and SS activity (synthetic direction), indicating that HpVAI1, HpNI4, and HpSS2 and HpSS5 were involved in the regulation of VAI, NI, and SS (synthetic direction), respectively. HpVAI1 and HpNI4 regulated sucrose degradation and the accumulation of glucose and fructose, while HpSS2 and HpSS5 regulated sucrose synthesis. These results suggest that HpVAI1 plays a key role in sugar metabolism during fruit development of ‘Hongshuijing’ pitaya. The results of this study provide new information about sugar metabolism in pitaya fruit that could help improve fruit quality and the breeding of new cultivars.

Ziziphus spina‐christi (L.) Willd. is a multi‐purpose plant and is very popular found in local markets because of its high nutritional and medicinal values. The present work was carried out to study morphological and chemical properties of native accessions of this species. There were significant differences among the accessions investigated based on the morphological and chemical characters. Total phenolic content ranged from 4.84 to 49.58 mg/g fresh weight (FW). Total flavonoid content varied from 0.45 to 2.29 mg/g FW. Antioxidant activity measured with DPPH ranged from 0.32 to 16.99 mg/g FW, while it ranged from 6.64 to 84.15 µM FeSO4 FW with the FRAP method. The total phenol content showed significant and positive correlations with total flavonoid content (r = 0.33), antioxidant activity obtained with DPPH (r = 0.85), and antioxidant activity obtained with FRAP (r = 0.54). The ward dendrograms divided the accessions studied into two major clusters based on morphological and chemical characteristics. Based on the traits related to fruit quality such as fruit weight, fruit skin color, and fruit flavor, as well as in terms of chemical characteristics related to medicinal properties such as total flavonoids and antioxidant activity, 17 accessions were superior that could be used in breeding programs or cultivated directly. The present results can be used in defining conservation strategies, genetic improvement, and crop production., Based on the traits related to fruit quality, 17 accessions were superior that could be used in breeding programs or cultivated directly.

Background. An important consumer trait of strawberry fruits is their aroma. Methyl anthranilate makes a considerable contribution to the fruit flavor. The methyl anthranilate content in strawberry fruits is controlled by the FanAAMT (аnthranilic acid methyltransferase) gene. Identification of genetic determinants for this trait facilitates targeted selection of promising forms based on diagnostic DNA markers. The purpose of this study was to study the allelic diversity of the FanAAMT fruit flavor gene in wild strawberry species and strawberry cultivars for identification of promising genotypes.Materials and methods. The objects of this study were wild species of Fragaria L. as well as F. × anaschata Kantor. and F. × ananassa Duch. cultivars of different ecogeographic origin. The FanAAMT gene was identified with the dominant marker FanAAMT.Results and conclusion. In the analyzed collection of strawberry genotypes, the FanAAMT gene was identified in 36.4% of the forms, including the wild species F. vesca L., F. moschata Duch. and F. virginiana subsp. platypetala (Rydb.) Staudt, and cv. ‘Kupchikha’ (F. × anaschata). Among the analyzed F. × ananassa cultivars, the FanAAMT gene was found in 31.6% of the tested forms, specifically in 27.3% of the 22 Russian cultivars, and 37.5% of the analyzed foreign ones. Promising sources of high methyl anthranilate content in fruits were identified: wild spp. F. moschata, F. vesca, and F. virginiana subsp. platypetala; cv. ‘Kupchikha’ (F. × anaschata); Russian garden strawberry cvs. ‘Bylinnaya’, ‘Zenit’, ‘Lastochka’, ‘Neznakomka’, ‘Feyerverk’ and ‘Tsarskoselskaya’; and foreign garden strawberry cvs. ‘Karmen’, ‘Ostara’, ‘Samson’, ‘Symphony’, ‘Troubadour’ and ‘Vima Tarda’, in which the functional allele of the FanAAMT gene was found. In the remaining studied strawberry genotypes the marker FanAAMT was not detected, which presumably indicates that the FanAAMT gene is absent. cells (R9.4.1).

Many fruits are harvested at the early ripening stage and left to attain an edible stage during the post-ripening process or by ethylene treatment. However, the post-ripening quality of fruit is generally inferior to the quality of fruit that ripened naturally. Sugar metabolism plays critical roles in regulating fruit flavor and stress responses. Methyl Jasmonate (MeJA) treatment modulates sugar accumulations and postharvest fruit quality. However, the regulation mechanism of MeJA on sugar metabolism and its relationship with fruit post-ripening quality are unclear. The results indicated that MeJA-treated fruit possessed higher total antioxidant, lycopene and soluble solids content and lower electrical conductivity and malondialdehyde content. Besides, the post-ripening quality of fruit was strongly related to the starch and sucrose content. Compared to the control and ethephon treatments, MeJA treatment increased the activities and transcript levels of amylase, sucrose phosphate synthase (SPS) and sucrose synthase (SUS), but decreased the activities and transcript levels of acid invertase and neutral invertase. Further analysis suggested that the sucrose content had a strongly positive correlation with the activities and transcript levels of SUS and SPS, except SlSPS2. Thus, MeJA treatment improved fruit post-ripening quality by regulating sugar metabolism.

Fruit quality is the main factor determining market competitiveness; it represents the combination of fruit flavor, color, size, and the contents of aromatic and bioactive substances. Research on the genetic basis of fruit quality can provide new information about fruit biology, promote genomic-assisted breeding, and provide technological support for the regulation of fruit quality via habitat selection and/or the control of environmental conditions. High-throughput sequencing is a powerful research method for studying fruit quality traits, and reference genome sequences for many important fruit crops have provided vast amounts of genomic data. To study fruit quality, it is important to select appropriate omics strategies and to analyze omics data meaningfully. Here, we summarize genomic mechanisms of fruit quality formation: gene duplication, transposable element insertion, structural variations and genome methylation in functional genes. We review the genomic, transcriptomic, and metabolomic strategies that have been used to study the genetic basis of fruit quality traits. We also describe some of the genes associated with fruit traits; these genes are a valuable resource for genomics-assisted breeding and are useful models for deciphering the mechanisms of agronomic traits, such as fruit color, size, hardness, aroma components, sugar and acid content. Finally, to maximize the application of omics information, we propose some further directions for research using omics strategies.

Fatty acid-derived volatile organic compounds (FA-VOCs) make significant contributions to tomato (Solanum lycopersicum) fruit flavor and human preferences. Short-chain FA-VOCs (C5 and C6) are among the most abundant and important volatile compounds in tomato fruits. The precursors of these volatiles, linoleic acid (18:2) and linolenic acid (18:3), are derived from cleavage of glycerolipids. However, the initial step in synthesis of these FA-VOCs has not been established. A metabolite-based genome-wide association study combined with genetic mapping and functional analysis identified a gene encoding a novel class III lipase family member, Sl-LIP8, that is associated with accumulation of short-chain FA-VOCs in tomato fruit. In vitro assays indicated that Sl-LIP8 can cleave 18:2 and 18:3 acyl groups from glycerolipids. A CRISPR/Cas9 gene edited Sl-LIP8 mutant had much lower content of multiple fruit short-chain FA-VOCs, validating an important role for this enzyme in the pathway. Sl-LIP8 RNA abundance was correlated with FA-VOC content, consistent with transcriptional regulation of the first step in the pathway. Taken together, our work indicates that glycerolipid turnover by Sl-LIP8 is an important early step in the synthesis of multiple short-chain FA-VOCs.

Selutui puka ( Tabernaemontana macrocarpa Jack) is a medicinal plant that grows in forests and river banks. This plant can be found in West Kutai, East Kalimantan. Empirically, the use of selutui puka fruit is used as a medicine for toothache and canker sores by boiling it, the cooking water is used by stew. The importance of simplicia characterization is to determine the quality of simplicia which will become the standard for traditional medicine. The purpose of this study was to determine the characteristics of simplicia powder from selutui puka fruit and to determine the class of chemical compounds contained in selutui puka fruit. This research is non experimental. The research starts from sampling, determination, making simplicia, characterization which includes macroscopic test, microscopic test, determination of moisture content, soluble ethanol extract content, water soluble extract content, moisture content, ash content, acid insoluble ash content and phytochemical screening. Data were analyzed using descriptive methods. Macroscopic and organoleptic characterization of simplicia powder has a distinctive aroma (aromatic), bitter fruit flavor, yellowish-brown simplicia powder, white meat, hard and runny meat. Microscopic results of simplicia powder are found in the endocarp, wooden vessels in the form of stairs, trachea, and cork tissue. The level of dissolved ethanol extract was 36%, water juice content was 47%, water content was 8%, ash content was 4.36%, acid insoluble ash content was 0.57%. The results of phytochemical screening contain alkaloids, saponins, and flavonoids.

Tomato has emerged as the model system for investigations into the regulation of fleshy-fruit ripening and senescence, and the ripening process involving the coordinated regulation at the gene/chromatin/epigenetic, transcriptional, post-transcriptional and protein levels. Noncoding RNAs play important roles in fruit ripening as important transcriptional and post-transcriptional regulatory factors. In this review, we systematically summarize the recent advances in the regulation of tomato fruit ripening involved in ethylene biosynthesis and signal transduction, fruit pigment accumulation, fruit flavor and aroma, fruit texture by noncoding RNAs and their coordinate regulatory network model were set up and also suggest future directions for the functional regulations of noncoding RNAs on tomato fruit ripening.

Fruit aroma is an important consumer attribute of strawberry varieties. The key volatile compounds of the aromatic complex of strawberry fruit are mesifurane (fruity and caramel aromas) and γ-decalactone (fruity, sweet, or peachy aroma). The mesifurane content in strawberry fruit is controlled by the FaOMT gene, which is mapped to the distal region of the long arm of chromosome VII-F.1. The γ-decalactone content in strawberry fruit is controlled by the FaFAD1 gene, mapped to the distal region of the long arm of chromosome III-2. Identification of forms carrying genes for fruit flavor volatiles is an important step in breeding varieties with fragrant fruit. The use of molecular markers allows highly reliable detection of target gene alleles in a genome at early developmental stages. This study involves molecular genotyping of Fragaria L. varieties for the FaOMT and FaFAD1 genes, analysis of polymorphism of the loci in question, and identification of genotypes valuable for breeding. The objects of our study were wild species of the genus Fragaria L. and strawberry varieties (Fragaria × ananassa Duch.) of different ecological and geographic origins. To assess the allelic states of the FaOMT gene, the codominant marker FaOMT-SI/NO was used, and for the FaFAD1 gene, the dominant marker FaFAD1. The functional allele of the FaOMT gene (FaOMT+) in the heterozygous state (FaOMT+FaOMT- genotype) was detected in 34.9 % of the accessions tested. The functional allele of the FaOMT gene in the homozygous state (FaOMT+FaOMT+ genotype) was detected in 51.2 % of the accessions. The homozygous state of the inactive allele (FaOMT-FaOMT- genotype) was detected in 13.9 % of the studied strawberry accessions. The FaFAD1 gene was identified in 25.6 % of the analyzed collection of strawberry genotypes, including the wild species F. orientalis Los., F. moschata Duch., F. ovalis Rydb. The combination of functional alleles of the FaOMT and FaFAD1 genes was detected in 16.3 % of the analyzed forms. The wild species F. orientalis Los. and F. moschata Duch. and strawberry variety Red Gauntlet combine the functional allele of the FaFAD1 gene with the homozygous state of the active allele of the FaOMT gene; therefore, we recommend them as promising sources of high contents of mesifurane and γ-decactone in fruit in breeding programs for fruit aroma.

Consumers consistently note that there is room for improvement in the flavor of commercial strawberries. Fruit flavor and aroma are affected by both genetics and environment. This work tests the hypothesis that sensory quality may be manipulated using postharvest light treatments. Individual detached fruits representing two different cultivars received a 24-hr treatment of 100 µmol m-2 s-1 blue LED light while the control was kept in complete darkness. Following treatment, samples were analyzed for flavor volatiles, sugars, acids, firmness, and sensory differences in human trials. Fruits were rated for overall liking, texture, sweetness, sourness, and overall strawberry flavor intensity (OSFI) on the sensory and hedonic versions of the global intensity scale (GIS). A positive treatment effect was observed for "Strawberry Festival" fruit for the overall liking rating. A triangle test revealed a significant treatment effect, as light-treated fruit tested higher in many flavor volatiles including those known to contribute to sweetness in strawberries. Levels of several volatiles were consistently higher in the treated fruit across all four harvests: acetic acid hexyl ester, butanoic acid octyl ester, methyl isovalerate, and pentanoic acid ethyl ester. The results show that postharvest light treatment can be used to modulate sensory quality of fruit, perhaps offering a means to complement genetic efforts in fruit flavor and aroma improvement. PRACTICAL APPLICATION: The results indicate that it may be possible to increase the sensory quality of strawberry fruits using an inexpensive and noninvasive light treatment. Light may be applied during transport or storage to improve fruit quality. This concept could also be extended into other realms of storage, such as residential and commercial refrigeration, further increasing the quality impact of the approach.

The storage period of ‘Nanguo’ pears (Pyrus ussuriensis Maxim.) can be effectively prolonged under low-temperature conditions. However, long-term refrigeration leads to the deterioration of fruit flavor and aroma through the loss of compounds such as volatile esters, resulting in lower commodity value of the stored fruit. In this study, the loss of ester was noted in fruit under long-term storage, evidenced by reduced variety of esters, lower contents of critical esters, and reduced total ester contents. Ethylene production was significantly lower in cold-stored samples than in samples without storage or with short-term storage. Linear regression analysis indicated that the loss of volatile esters induced by cold storage was related to low ethylene production. Exogenous ethylene treatment relieved the loss of esters, producing more and higher contents of esters, as well as improving activities of enzymes involved in ester biosynthesis. Further analysis showed that ethylene production was promoted and that expression levels of key genes involved in ethylene signal transduction, including PuERS1, PuEIN4, PuEIN2, PuEIN3, and PuERF1, were upregulated in ET-treated fruit. Hence, it was concluded that the aroma quality of cold-stored ‘Nanguo’ pears can be improved by ethylene treatment due to the induced enhancement of ethylene biosynthesis and signal transduction.

Sugars, acids, and aroma volatiles are essential flavor components of fruit; the fatty acid metabolic pathway is regarded as key to formation of fruit aroma compounds. In this study, we investigated the comparative influence of different storage temperatures on apricot flavor compounds during shelf storage using the Shushanggan apricot (Prunus armeniaca L. ‘Shushanggan’), which is rich in sugars, acids, and aroma volatiles. Three low temperature storage conditions, namely 10 °C, 5 °C, and near freezing point storage (NFPT), were compared and ethylene production and the content of three sugars, two acids, four “green” aroma volatiles, and six “fruity” aroma volatiles were determined; in addition, the activity of aroma related enzymes in the fatty acid metabolic pathway were investigated. In general, the content of the three sugars (fructose, glucose and sucrose) and the two acids (citric acid and malic acid) were not significantly affected by temperature. In contrast, compared with the control, the “green” and “fruity” aroma volatiles were reduced to varying degrees at the three low temperature storage conditions. However, at the medium storage stage, the “green” and “fruity” aroma volatiles could recover to normal levels, whereas at the terminal stage of storage the volatile recovery showed an unresponsive result. In fruit stored at near freezing point, aroma volatiles recovered in content; however, irreversible reduction in the nine aroma volatiles occurred at 5 °C storage. With regard to activities of enzymes in the fatty acid pathway, lipoxygenase activity was not affected by temperature but hydroperoxide lyase, alcohol dehydrogenase, and alcohol acyltransferase showed clear inhibition at 5 °C storage. The changes in volatile compounds were closely related to apricot fruit maturation manifested in color changes and production of ethylene. The results presented here indicate that after prolonged storage at low temperature, flavor loss was mostly related to effects on aroma volatiles rather than on sugars or acids. NFPT storage was found to be the most effective way to maintain the flavor and shelf storage of apricot fruit after storage.

Blueberries are now the second most economically important soft fruit. However, they are highly perishable and susceptible to rapid spoilage. Softening is one of the main reasons for short postharvest life of blueberries. The changes of fruit firmness, weight loss, flavor quality and cell wall composition of Vaccinium corymbosum cv. Bluecrop and Vaccinium corymbosum cv. Sierra were investigated in this study. The results showed that fruit firmness declined concomitantly with the increase of fruit weight loss and water soluble pectin (WSP) content paralleled by a decrease in the content of cellulose (CEL) and hemicellulose (HCEL) during postharvest cold storage at 0 ℃ and 90% relative humidity. Compared with Sierra blueberries, Bluecrop blueberries were much more resistant to postharvest cold storage as manifested by the higher values in fruit flavor quality and firmness which were associated with less weight loss, lower WSP content and higher amount of CEL and HCEL.

A narrow genetic basis in modern cultivars and strong linkage disequilibrium in peach (Prunus persica) has restricted resolution power for association studies in this model fruit species, thereby limiting our understanding of economically important quality traits including fruit flavor. Here, we present a high-quality genome assembly for a Chinese landrace, Longhua Shui Mi (LHSM), a representative of the Chinese Cling peaches that have been central in global peach genetic improvement. We also map the resequencing data for 564 peach accessions to this LHSM assembly at an average depth of 26.34× per accession. Population genomic analyses reveal a fascinating history of convergent selection for sweetness yet divergent selection for acidity in eastern vs. western modern cultivars. Molecular-genetics and biochemical analyses establish that PpALMT1 (aluminum-activated malate transporter 1) contributes to their difference of malate content and that increases fructose content accounts for the increased sweetness of modern peach fruits, as regulated by PpERDL16 (early response to dehydration 6-like 16). Our study illustrates the strong utility of the genomics resources for both basic and applied efforts to understand and exploit the genetic basis of fruit quality in peach., Longhua Shui Mi (LHSM) is a representative of the Chinese Cling peaches that have been central in global peach genetic improvement. Here, the authors assemble the genome of LHSM and show convergent selection for sweetness yet divergent selection for acidity in eastern vs. western cultivars through population genomics analyses.

Strawberries produce numerous volatile compounds that contribute to the unique flavors of fruits. Among the many volatiles, γ-decalactone (γ-D) has the greatest contribution to the characteristic fruity aroma in strawberry fruit. The presence or absence of γ-D is controlled by a single locus, FaFAD1. However, this locus has not yet been systematically characterized in the octoploid strawberry genome. It has also been reported that the volatile content greatly varies among the strawberry varieties possessing FaFAD1, suggesting that another genetic factor could be responsible for the different levels of γ-D in fruit. In this study, we explored the genomic structure of FaFAD1 and determined the allele dosage of FaFAD1 that regulates variations of γ-D production in cultivated octoploid strawberry. The genome-wide association studies confirmed the major locus FaFAD1 that regulates the γ-D production in cultivated strawberry. With the hybrid capture-based next-generation sequencing analysis, a major presence–absence variation of FaFAD1 was discovered among γ-D producers and non-producers. To explore the genomic structure of FaFAD1 in the octoploid strawberry, three bacterial artificial chromosome (BAC) libraries were developed. A deletion of 8,262 bp was consistently found in the FaFAD1 region of γ-D non-producing varieties. With the newly developed InDel-based codominant marker genotyping, along with γ-D metabolite profiling data, we revealed the impact of gene dosage effect for the production of γ-D in the octoploid strawberry varieties. Altogether, this study provides systematic information of the prominent role of FaFAD1 presence and absence polymorphism in producing γ-D and proposes that both alleles of FaFAD1 are required to produce the highest content of fruity aroma in strawberry fruit.

Metabolites have been reported as the main factor that influences the fruit flavor of watermelon. But the comprehensive study on the dynamics of metabolites during the development of watermelon fruit is not up-to-date. In this study, metabolome and transcriptome datasets of ‘Crimson’ watermelon fruit at four key developmental stages were generated. A total of 517 metabolites were detected by ultrahigh-performance liquid chromatography–electrospray ionization–tandem mass spectrometry and gas chromatography–solid-phase microextraction–mass spectrometry. Meanwhile, by K-means clustering analysis, the total differentially expressed genes were clustered in six classes. Integrating transcriptome and metabolome data revealed similar expression trends of sugars and genes involved in the glycolytic pathway, providing molecular insights into the formation of taste during fruit development. Furthermore, through coexpression analysis, we identified five differentially expressed ADH (alcohol dehydrogenase) genes (Cla97C01G013600, Cla97C05G089700, Cla97C01G001290, Cla97C05G095170, and Cla97C06G118330), which were found to be closely related to C9 alcohols/aldehydes, providing information for the formation of fruit aroma. Our findings establish a metabolic profile during watermelon fruit development and provide insights into flavor formation.

Fragaria × ananassa Duch, which among the youngest fruit crops, comprises many popular cultivars that are famous for their favored color and aroma. The regulation roles of AP2/ERF (APETALA2/ethylene-responsive element-binding factor) transcription factors in fruit flavor and color regulation have been studied in several fruit crops. The AP2 family of strawberry, which was ignored in recent AP2/ERF identification studies, was explored in this study. A total of 64 FaAP2 (Fragaria × ananassa AP2) transcription factors belonging to the euAP2, euANT (AINTEGUMENTA), and baselANT groups were identified with canonical insertion motifs in two AP2 domains. The motif identification illustrated that motifs 1, 5, and 2 indicated a corresponding AP2 domain repeat 1 with a linker region, and motifs 6, 4, 3 indicated a corresponding AP2 domain repeat 2, all of which were highly conserved. By synteny analysis, FaAP2 paralogs were identified in each sub-genome, and FaAP2 gene duplication and loss explained the unequal AP2 loci of sub-genomes. The expression profile in three cultivars indicated that six FaAP2 paralogs—four WRI (WRINKLED) gene homologs and two AP2 gene homologs—were candidate regulators of red fruit color and/or special fruit aroma. All these finds provide a basis for further investigations into role of AP2 in fruit color and aroma and would be helpful in the targeted selection of strawberry fruit quality to improve breeding.

Flavor-associated volatile chemicals make major contributions to consumers' perception of fruits. Although great progress has been made in establishing the metabolic pathways associated with volatile synthesis, much less is known about the regulation of those pathways. Knowledge of how those pathways are regulated would greatly facilitate efforts to improve flavor. Volatile esters are major contributors to fruity flavor notes in many species, providing a good model to investigate the regulation of volatile synthesis pathways. Here we initiated a study of peach (Prunus persica L. Batsch) fruits, and identified that the alcohol acyltransferase PpAAT1 contributes to ester formation. We next identified the transcription factor (TF) PpNAC1 as an activator of PpAAT1 expression and ester production. These conclusions were based on in vivo and in vitro experiments and validated by correlation in a panel of 30 different peach cultivars. Based on homology between PpNAC1 and the tomato (Solanum lycopersicum) TF NONRIPENING (NOR), we identified a parallel regulatory pathway in tomato. Overexpression of PpNAC1 enhances ripening in a nor mutant and restores synthesis of volatile esters in tomato fruits. Furthermore, in the NOR-deficient mutant tomatoes generated by CRISPR/Cas9, lower transcript levels of SlAAT1 were detected. The apple (Malus domestica) homolog MdNAC5 also stimulates MdAAT1 expression via binding to this gene's promoter. In addition to transcriptional control, epigenetic analysis showed that increased expression of NACs and AATs is associated with removal of the repressive mark H3K27me3 during fruit ripening. Our results support a conserved molecular mechanism in which NAC TFs activate ripening-related AAT expression, which in turn catalyzes volatile ester formation in multiple fruit species.

International audience; Soluble sugars, organic acids and volatiles are important components that determine unique fruit flavor and consumer preferences. However, the metabolic dynamics and underlying regulatory networks that modulate overall flavor formation during fruit development and ripening remain largely unknown for most fruit species. In this study, by integrating flavor-associated metabolism and transcriptome data from 12 fruit developmental and ripening stages of Actinidia chinensis cv Hongyang, we generated a global map of changes in the flavor-related metabolites throughout development and ripening of kiwifruit. Using this dataset, we constructed complex regulatory networks allowing to identify key structural genes and transcription factors that regulate the metabolism of soluble sugars, organic acids and important volatiles in kiwifruit. Moreover, our study revealed the regulatory mechanism involving key transcription factors regulating flavor metabolism. The modulation of flavor metabolism by the identified key transcription factors was confirmed in different kiwifruit species providing the proof of concept that our dataset provides a suitable tool for clarification of the regulatory factors controlling flavor biosynthetic pathways that have not been previously illuminated. Overall, in addition to providing new insight into the metabolic regulation of flavor during fruit development and ripening, the outcome of our study establishes a foundation for flavor improvement in kiwifruit.

Fruit flavor is defined as the perception of the food by the olfactory and gustatory systems, and is one of the main determinants of fruit quality. Tomato flavor is largely determined by the balance of sugars, acids and volatile compounds. Several genes controlling the levels of these metabolites in tomato fruit have been cloned, including LIN5, ALMT9, AAT1, CXE1, and LoxC. The aim of this study was to identify any association of these genes with trait variation and to describe the genetic diversity at these loci in the red-fruited tomato clade comprised of the wild ancestor Solanum pimpinellifolium, the semi-domesticated species Solanum lycopersicum cerasiforme and early domesticated Solanum lycopersicum. High genetic diversity was observed at these five loci, including novel haplotypes that could be incorporated into breeding programs to improve fruit quality of modern tomatoes. Using newly available high-quality genome assemblies, we assayed each gene for potential functional causative polymorphisms and resolved a duplication at the LoxC locus found in several wild and semi-domesticated accessions which caused lower accumulation of lipid derived volatiles. In addition, we explored gene expression of the five genes in nine phylogenetically diverse tomato accessions. In general, the expression patterns of these genes increased during fruit ripening but diverged between accessions without clear relationship between expression and metabolite levels.

Introducción: El fruto de la feijoa ha cobrado relevancia internacional debido a sus altas propiedades nutraceúticas. En contraste con Nueva Zelanda, Colombia o Turquía, en México, su cultivo es incipiente y hasta el momento se produce solamente en los estados de México, Michoacán, Puebla y Veracruz. Un problema que existe en México para la venta de este fruto es su baja comercialización. Así, estudiar las variables que influyen en el proceso de decisión de compra es relevante. El objetivo del presente estudio fue caracterizar algunos atributos sensoriales del nuevo consumidor de feijoa fresca, así como el grado de afectividad que tienen por esta fruta.Método: Las características sensoriales de la feijoa (Acca sellowiana), carambola (Averrhoa carambola), kiwi (Actinidia chinensis) y guayaba (Psidium guajava) fueron analizadas. Con el perfil sensorial de estos frutos, se realizó un análisis descriptivo cuantitativo (ADC), y posteriormente se llevó a cabo una prueba de aceptabilidad que determinó la afectividad de los consumidores sobre determinados atributos sensoriales del fruto. También, se realizó una prueba de preferencia afectiva por pares entre la feijoa y la guayaba. Resultados y discusión: los atributos sensoriales que caracterizaron a la feijoa fueron su aroma dulce, intensidad de aroma y sabor residual frutal; la carambola sobresalió en jugosidad; la guayaba en intensidad de aroma y acidez; y el kiwi en acidez y homogeneidad. De las cuatro frutas comparadas, la feijoa presentó los valores más altos en acidez, aroma dulce, intensidad de aroma, homogeneidad, dureza y sabor residual frutal. En cuanto a aceptabilidad global, la guayaba, el kiwi y la feijoa fueron las más gustadas por los consumidores.Conclusión: La feijoa mostró superioridad en la mayoría de los atributos sensoriales. El aroma dulce y la intensidad del aroma favorecieron su aceptación con respecto al kiwi, carambola y guayaba. En contraste, su jugosidad, pegajosidad, y acidez tuvieron valores que afectaron negativamente su aceptabilidad. La guayaba fue aceptada mientras tenga menor acidez. El kiwi tuvo atributos como pegajosidad y bajo sabor residual frutal aceptados favorablemente. La carambola tuvo la menor aceptación debido a la alta acidez, sin embargo, tuvo atributos como homogeneidad y jugosidad que gustaron a los consumidores.

Volatile compositions and sensory characteristics of 11 commercially distilled soju samples were investigated using headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) and sensory descriptive analysis. A total of 59 major volatile compounds, consisting of 32 esters, 10 alcohols, 2 acids, 5 aldehydes, 3 ketones, 1 hydrocarbon, 1 furan, 2 phenols, and 3 miscellaneous compounds, were identified. From the principal component analysis (PCA) of volatile data, MSJ made by atmospheric distillation showed a clear distinction in volatile compositions compared to that of other samples made by vacuum distillation. Based on PCA of the sensory data determined by a panel of ten judges, MSJ was associated with a large amount of longer chain esters that showed high intensities in bitter taste and yeast/nuruk-related flavor attributes. HYJ, LPJ, and HAJ made with rice as a raw material were associated with lower intensities of the alcohol aroma, while JRJ and OKJ aged in oak barrels were associated with fruit flavor, sweet flavor, and brandy aroma. In the partial least squares regression (PLSR) analysis to see any relationship between volatile and sensory data, longer chain esters like ethyl tetradecanoate, and ethyl hexadecanoate were highly associated with bleach aroma. In contrast, positive correlations were seen with barley aroma and yeast flavor with hexanal, nonanal, benzaldehyde, and 2-methoxy-phenol.

Although they are staple foods in cuisines globally, many commercial fruit varieties have become progressively less flavorful over time. Due to the cost and difficulty associated with flavor phenotyping, breeding programs have long been challenged in selecting for this complex trait. To address this issue, we leveraged targeted metabolomics of diverse tomato and blueberry accessions and their corresponding consumer panel ratings to create statistical and machine learning models that can predict sensory perceptions of fruit flavor. Using these models, a breeding program can assess flavor ratings for a large number of genotypes, previously limited by the low throughput of consumer sensory panels. The ability to predict consumer ratings of liking, sweet, sour, umami, and flavor intensity was evaluated by a 10-fold cross-validation, and the accuracies of 18 different models were assessed. The prediction accuracies were high for most attributes and ranged from 0.87 for sourness intensity in blueberry using XGBoost to 0.46 for overall liking in tomato using linear regression. Further, the best-performing models were used to infer the flavor compounds (sugars, acids, and volatiles) that contribute most to each flavor attribute. We found that the variance decomposition of overall liking score estimates that 42% and 56% of the variance was explained by volatile organic compounds in tomato and blueberry, respectively. We expect that these models will enable an earlier incorporation of flavor as breeding targets and encourage selection and release of more flavorful fruit varieties.

Sugar from plant photosynthesis is a basic requirement for life activities. Sugar transporters are the proteins that mediate sugar allocation among or within source/sink organs. The transporters of the major facilitator superfamily (MFS) targeting carbohydrates represent the largest family of sugar transporters in many plants. Strawberry (Fragaria × ananassa Duchesne) is an important crop appreciated worldwide for its unique fruit flavor. The involvement of MFS sugar transporters (STs) in cultivated strawberry fruit sugar accumulation is largely unknown. In this work, we characterized the genetic variation associated with fruit soluble sugars in a collection including 154 varieties. Then, a total of 67 ST genes were identified in the v4.0 genome integrated with the v4.0.a2 protein database of F. vesca, the dominant subgenome provider for modern cultivated strawberry. Phylogenetic analysis updated the nomenclature of strawberry ST homoeologs. Both the chromosomal distribution and structural characteristics of the ST family were improved. Semi-RT-PCR analysis in nine tissues from cv. Benihoppe screened 34 highly expressed ST genes in fruits. In three varieties with dramatically differing fruit sugar levels, qPCR integrated with correlation analysis between ST transcript abundance and sugar content identified 13 sugar-correlated genes. The correlations were re-evaluated across 19 varieties, including major commercial cultivars grown in China. Finally, a model of the contribution of the sugar transporter system to subcellular sugar allocation in strawberry fruits was proposed. Our work highlights the involvement of STs in controlling strawberry fruit soluble sugars and provides candidates for the future functional study of STs in strawberry development and responses and a new approach for strawberry genetic engineering and molecular breeding.

Volatile compounds play key roles in the fruit, as they are involved in defense against pests and diseases, act as a cue to attract or repel seed dispersers, and are major components determining fruit flavor. In this chapter we describe the different types of volatile biosynthetic pathways operating in fruit and highlight the key steps by incorporating the latest advances from genomics and biochemistry. Ripe fruits typically produce a blend consisting of a few hundreds of volatile compounds of different chemical nature that originate from several independent metabolic pathways. To illustrate the diversity of volatiles pathways operating in different fruit specific sections are dedicated to each of the ten most produced/consumed fruit species. As fruit volatile production is a highly dynamic and tightly coordinated along the process of ripening and in response to environment this chapter also includes a section on the latest advances in the regulation of the biosynthesis of fruit volatiles.

Bagging is widely practiced to produce high quality and unblemished fruit, however, little is currently known about the effect of bagging on flavor and nutritional quality of cucumber fruits. Here we determined the influence of bagging on fruit quality of cucumber (Cucumis sativus L.) using three genotypes from different geographic groups. Exocarp chlorophyll and carotenoid levels were significantly decreased by bagging, accompanied by color change. Ascorbate content in bagged fruits decreased to some extent, while contents of soluble sugars, starch, and cellulose were comparable with those of control fruits. Compositions related to fruit flavor quality could be enhanced largely through bagging treatment, with elevation of the relative proportion of C6 aldehyde, as well as (E,Z)-2,6-nonadienal/(E)-2-nonenal ratio, and linoleic/&alpha, linolenic acid ratio. Lipoxygenase and hydroperoxide lyase, two key enzymes in the production of volatiles, displayed distinctive transcript expression patterns and trends in changes of enzymatic activity in the bagged fruits of different genotypes. Overall, this study assesses the information on changing characteristics of fruit volatile composition and nutritional quality among different cucumber genotypes after bagging treatment. Results of this study would contribute to providing reference for mechanism study and cultivation conditions to improve cucumber fruit flavor to a considerable degree.

Most consumers complain about the flavor of current tomato cultivars and many pay a premium for alternatives such as heirloom varieties. Breeding for fruit flavor is difficult because it is a quantitatively inherited trait influenced by taste, aroma and environmental factors. A lack of genetic diversity in modern tomato cultivars also necessitates exploration of new sources for flavor alleles. Wild tomato S. pimpinellifolium and inbred backcross lines were assessed for individual sugars and organic acids which are two of the main components of tomato flavor. S. pimpinellifolium was found to harbor alleles that could be used to increase glucose and fructose content and adjust acidity by altering malic and citric acid levels. Single nucleotide polymorphism markers were used to detect 14 quantitative trait loci (QTLs) for sugars and 71 for organic acids. Confirmation was provided by comparing map locations with previously identified loci. Thus, seven (50 %) of the sugar QTLs and 22 (31 %) of the organic acids loci were supported by analyses in other tomato populations. Examination of the genomic sequence containing the QTLs allowed identification of potential candidate genes for several flavor components.

Kiwifruit harvested at the correct maturity can be stored for up to 4–5 months. The storage life can be maximized by the use of controlled atmosphere (CA) or modified atmosphere (MA) conditions. Optimal storage atmospheres depend on the cultivar. Key quality criteria for kiwifruit are fruit firmness and freedom from defects. Also, the fruit flavor and flesh color should match consumer expectations for the cultivar. While CA and MA conditions may delay fruit ripening, incorrect atmospheres may damage the fruit, most obviously through anaerobic metabolism. Fruit quality problems associated with ripening may be delayed, but not solved, by the use of CA and MA. A major risk to kiwifruit storage is accelerated ripening in response to ethylene. This chapter discusses the main causes of quality loss, the optimum storage conditions, and potential problems which may occur in storing kiwifruit.

Collection, characterization and utilization of genetic resources are crucial for developing varieties to meet current and future needs. Although mango is an economically important fruit tree, its genetic resources are still undocumented and are threatened in their natural habits. In this study, the variability of 452 mango accessions from three regions in China (Nujiang, Lancang river and Honghe) was assessed using 41 descriptors including qualitative and quantitative traits, with the aim to identify mango accessions with excellent agronomic and quality traits. To this end, descriptive and multivariate analyses were performed. Based on Shannon&ndash, Weaver diversity index, qualitative traits including pericarp color, fruit aroma, flesh color, and fruit flavor recorded the highest variability in the germplasm. Fruit related traits including pulp weight, peel weight, and fruit weight were the most diverse traits in the germplasm with a high coefficient of variation (CV &gt, 40%). Significant differences (MANOVA test, p &lt, 0.000) were observed among the three regions for most of the quantitative traits. Biologically significant and positive correlations were found among agronomically important traits such as fruit weight and pulp weight, fruit weight and edible rate. The hierarchical cluster analysis revealed tree clusters, indicating a low diversity in the germplasm. The majority of the descriptors contributed to the differentiation of the accessions. Accessions with good fruits quality (high fruit weight, pulp weight, and edible rate) were found in Cluster 2. Accessions in this cluster could be used for fruit quality improvement in mango breeding programs. Our study sheds light on the diversity of a large collection of natural mango population in China and provides relevant information for efficient conservation and harnessing of mango genetic resources.

Organic nutrient solution is non-polluting and environmentally friendly. Supplying organic nutrient solution instead of chemical fertilizer is helpful in enhancing the aroma and sweetness of ripe tomato fruits. However, the mechanism is still unclear for improving the ripe fruit flavor. We combined transcriptome and metabolomic analyses to answer questions about the synthesis of soluble sugars, organic acids, and aroma volatiles in cherry tomato fruits with changes in metabolites and genes associated with the metabolic pathways. We found that tomatoes supplemented with organic nutrient solutions had the same fruit yield as those supplied with inorganic nutrient solutions; however, the tomatoes supplemented with organic nutrient solutions had increased in phenylalanine and its downstream phenolic volatiles, in addition, methyl salicylate, a unpopular, medicinal-smelling volatiles, was decreased, due to changed expression levels of the key genes (LeAADC, LePAR, SlSAMT); we also observed that organic acid metabolism and the synthesis of fructose and glucose were promoted. The expression level of LOC101254693 (pyruvate dehydrogenase) driving pyruvate metabolism was upregulated. This affects the rate of metabolism of the pyruvate-linked TAC cycle and glycolysis. This study analyzed the positive effects of organic nutrient solutions on the ripe fruit flavor at the molecular level, facilitating further optimization of nutrient solution formulations for soilless tomato cultivation.

Banana fruit is sensitive to chilling injury, which not only causes physical damage but also dramatically reduces fruit flavor. In this work, we evaluated the influence of non-chilling low temperature (NCT, 13 °C) and chilling temperature (CT, 5 °C) storage on volatiles production in banana in comparison to control conditions (20 °C) and evaluated the possible mechanisms. We found that CT storage caused chilling injury, which negatively affected the physical appearance of the fruit and dramatically reduced volatiles production, especially fruity note volatiles, such as esters. In contrast, NCT storage only reduced the production of a few specific volatiles. Both NCT and CT affected volatile-related amino acid and biosynthetic precursors of fatty acid compositions. The expression levels of the volatiles biosynthesis-related genes, MaHPL, MaLOX, and MaAAT, were repressed by low temperature (NCT and CT), particularly chilling temperature, while MaADH and MaPDC were up-regulated. These results suggest that CT significantly reduces volatiles production by regulating different key enzymes and genes involved in volatiles biosynthetic pathways and is mainly mediated via the repression of the lipoxygenase and amino acid metabolic pathways.

A coordinated regulation of different metabolic pathways was highlighted leading to the accumulation of important compounds that may contribute to the final quality of strawberry fruit. Strawberry fruit development and ripening involve complex physiological and biochemical changes, ranging from sugar accumulation to the production of important volatiles compounds that contribute to the final fruit flavor. To better understand the mechanisms controlling fruit growth and ripening in cultivated strawberry (Fragaria × ananassa), we applied a molecular approach combining suppression subtractive hybridization and next generation sequencing to identify genes regulating developmental stages going from fruit set to full ripening. The results clearly indicated coordinated regulation of several metabolic processes such as the biosynthesis of flavonoid, phenylpropanoid and branched-chain amino acids, together with glycerolipid metabolism and pentose and glucuronate interconversion. In particular, genes belonging to the flavonoid pathway were activated in two distinct phases, the first one at the very early stages of fruit development and the second during ripening. The combination of expression analysis with metabolomic data revealed that the functional meaning of these two inductions is different, as during the early stages gene activation of flavonoid pathway leads to the production of proanthocyanidins and ellagic acid-derived tannins, while during ripening anthocyanins are the main product of flavonoid pathway activation. Moreover, the subtractive approach allowed the identification of different members of the same gene family coding for the same or very similar enzymes that in some cases showed opposite regulation during strawberry fruit development. Such regulation is an important trait that can help to understand how plants specifically channel metabolic intermediates towards separate branches of a biosynthetic pathway or use different isoforms of the same enzyme in different organs or developmental stages.

Plant alcohols and aldehydes are produced by the action of alcohol dehydrogenases (ADH) and play an important role during fruit ripening and aroma production. Alcohols are not only produced in different tissues at different stages of plant development but are also products of the fermentative pathway which gets activated by different stresses, including hypoxia. The ADH gene is a well-established marker for hypoxic response as well as plant aroma. In a previous report we have identified and characterized three ADHs (MiADH1, 2, 3) from Dashehari mango. MiADH1 was found to be fruit specific and was upregulated by ethylene and ABA, suggesting a role in fruit aroma volatile production. In order to functionally characterize MiADH1, transgenic tomato plants were developed under the control of the constitutive (CaMV35S) promoter. Transgenic tomato fruit expressing MiADH1 gene showed a change in the levels of several alcohols and aldehydes related to flavor in comparison to the control. The change in aroma and volatiles compounds was more prominent during the ripe stage as compared to unripe and mid-ripe stages of tomato fruit. The transgenic tomato plants also produced adventitious roots. Our results suggest that the overexpression of MiADH1 in tomato plants induced the fermentative pathway in roots, and mimicked hypoxic response by development of adventitious roots from the stem as an adaptive mechanism.

1-Methylcyclopropene (1-MCP) can maintain the physical quality of climacteric fruits, such as apple and pear, but inhibit aroma volatile production and fruit flavor. In this study, the effects of calcium (Ca) in combination with 0.6 and 1.0 μL L−1 1-MCP on flesh firmness and aroma volatiles has been investigated on ‘Fuji’ apples stored at room temperature. Results from electronic nose detection and texture evaluation showed that 1-MCP of reduced concentration (0.6 μLL−1), but not 1.0 μL L−1, presented an interactive effect with Ca application on promoting volatile emission and reducing softening. The amount of branched and straight esters and total aroma volatiles, as well as related enzymes including aromatase-related acyltransferase (AAT), alcohol dehydrogenase (ADH), and pyruvate decarboxylase (PDC), were significantly higher in fruit treated with (1-MCP 0.6 + Ca) than 1-MCP 1.0 after 50 and 100 days storage. There was no significant difference between two treatments of (1-MCP 0.6 + Ca) and 1-MCP 1.0 in maintaining fruit firmness. Fruit treated with (1-MCP 0.6 + Ca) had higher aroma quality than 1-MCP 1.0 according to sensory evaluation, but showed no significant difference in terms of texture quality. In conclusion, 1-MCP of reduced concentration combined with Ca treatment had synergetic effect on the aroma formation and softening inhibition of apple fruit, resulting in advanced sensory quality.

The objective of this research was to evaluate whether an electronic tongue (e-tongue) could differentiate “taste” profiles of full ripe tomato fruit of different cultivars, harvest maturities, and exposure to refrigeration or blanching. The four cultivars included: two common commercial cultivars, ‘Tygress’ and ‘FL 47’, with round shape and firm texture; ‘Tasti-Lee’, a hybrid with high lycopene content due to the crimson gene for the premium tomato market; and ‘Cherokee Purple’, an heirloom cultivar that consistently ranked very high in taste tests. Commercially, tomatoes are often harvested at the mature green (MG) stage for the fresh fruit and food service markets, and traditional vine-ripe harvested tomatoes are generally sold directly at farmer’s markets. To assess the effect of harvest maturity on fruit flavor once the fruit are fully ripened, fruit were harvested at six maturities from MG to full red. ‘Tygress’, ‘FL 47’, and ‘Tasti-Lee’ fruit all had similar total soluble solids (TSS) and titratable acidity (TA) content regardless of harvest maturity. Nonetheless, ‘Cherokee Purple’ had much higher TSS and TA at all but the MG harvest stage. E-tongue tests not only confirmed the differences detected in TSS/TA data, but also differentiated between the three commercial cultivars, and six harvest maturities. Both refrigeration and blanching are common kitchen practices and they were tested on ‘Tasti-Lee’ fruit for which some changes in the taste profiles were found by e-tongue, especially for the refrigeration treatment. E-tongue sensors ZZ, JE, BB, HA, and JB data correlated to TSS and TA, with significantly high correlations with TSS. E-tongue profiles not only significantly related to TSS, but successfully predicted TSS.

The effect of maturity stage on fruit quality characteristics, sensory attributes and volatile composition was investigated in the most important hawthorn cultivar (Sultan). The fruit skin color was used as the maturity index for the classification of hawthorn considering their maturity stages as immature (green), mature (green-yellow) and over mature (yellow). The volatile organic compounds (VOCs) of hawthorn fruit at each maturity stage were analyzed by solid-phase micro-extraction (SPME) and gas chromatography-mass spectrometry (GC–MS). The results indicated that the quality traits of the Sultan cultivar were affected by the maturity stage. From immature to over mature stages, firmness and titratable acidity decreased whereas fruit size (weight, diameter and length), edible fruit ratio, pH and esters (butyl and hexyl hexanoates, hexyl and cis-3-hexenyl acetates) increased in Sultan cultivar. The highest amount of esters along with the occurrence of butyl butanoate was observed in over mature fruit in comparison with immature and mature ones. PCA analysis of volatile organic compounds separated successfully hawthorn fruit according to the maturity stages. The results showed that mature and over mature fruit were more preferred by panelists. Those fruit had the highest level of esters being responsible for strong fruit flavor, along with low pH and low fruit firmness compared to immature ones.

Bell pepper is a model for studying the ripening process of non-climacteric fleshy fruit, during which numerous physiological changes occur. UV-C irradiation is an abiotic stress, which has an important influence on plant growth, development and ripening. We explored the influences of UV-C irradiation on physiological changes in bell pepper fruit during postharvest storage by measuring sensory quality, firmness and mass loss, and the underlying changes at the molecular level by combined transcriptome and metabolome analysis. Effects were detected on transcripts for numerous critical enzymes involved in fruit pigment accumulation, fruit texture change, fruit flavor and aroma production. Moreover, transcripts for several key enzymes and transcription factors involved in plant hormone pathways and their corresponding noncoding RNAs were identified and differential expression profiles were also analyzed. Components of a competing endogenous RNAs (ceRNA) regulatory network changed in response to UV-C irradiation and the relationships between them was analyzed. Thirty-one differentially expressed metabolites were identified. Combined transcriptome and metabolome analysis showed that the genes and metabolites that responded to UV-C were mainly involved in flavonoid, phenylalanine, tyrosine, tryptophan and phenylpropanoid biosynthesis. This study provides insights into bell pepper fruit physiology and the effects of UV-C irradiation on postharvest quality and enhances our understanding of the underlying mechanism whereby UV-C delays postharvest physiological changes in bell pepper fruit.

Citrus are rich in volatile terpenoids related to fruit flavor and defence response. Remarkable differences in Citrus volatiles provide us an ideal plant material to characterize novel genes associated with volatile formation. Bicyclogermacrene, a sesquiterpene, has high free radical scavenging activity and accumulates in finger citron (Citrus medica L. var. Sarcodactylis Hort) that belongs to wild species of Citrus family. In the present study, CmTPS1 comprised of 1668 base pairs was cloned, belonging to TPS-a subfamily. Transiently transform in tobacco leaf cells showed that CmTPS1 protein localized in the cytoplast. Enzyme activity assay showed that recombinant CmTPS1 catalyzed in vitro formation of bicyclogermacrene toward farnesyl diphosphate (FPP) as the substrates. Homologous transient over-expression in finger citron indicated that CmTPS1 also contributed to in vivo biosynthesis of bicyclogermacrene. Accumulated concentration of bicyclogermacrene positively correlated with CmTPS1 transcripts in developing fruit, flowers and leaves of finger citron. Melatonin treatment increased bicyclogermacrene contnent and CmTPS1 transcripts levels. Bicyclogermacrene was detected in finger citron fruit, but was under detected limits in mandarin, sweet orange and Citrus hybrids. Similar profile was observed for transcript levels of CmTPS1. These results indicated that CmTPS1 was associated with formation of sesquiterpene bicyclogermacrene in Citrus.

SUMMARY Tomato (Solanum lycopersicum L.) has become a popular model for genetic studies of fruit flavor in the last two decades. In this article we present a study of tomato fruit flavor, including an analysis of the genetic, metabolic and sensorial variation of a collection of contemporary commercial glasshouse tomato cultivars, followed by a validation of the associations found by quantitative trait locus (QTL) analysis of representative biparental segregating populations. This led to the identification of the major sensorial and chemical components determining fruit flavor variation and detection of the underlying QTLs. The high representation of QTL haplotypes in the breeders’ germplasm suggests that there is great potential for applying these QTLs in current breeding programs aimed at improving tomato flavor. A QTL on chromosome 4 was found to affect the levels of the phenylalanine‐derived volatiles (PHEVs) 2‐phenylethanol, phenylacetaldehyde and 1‐nitro‐2‐phenylethane. Fruits of near‐isogenic lines contrasting for this locus and in the composition of PHEVs significantly differed in the perception of fruity and rose‐hip‐like aroma. The PHEV locus was fine mapped, which allowed for the identification of FLORAL4 as a candidate gene for PHEV regulation. Using a gene‐editing‐based (CRISPR‐CAS9) reverse‐genetics approach, FLORAL4 was demonstrated to be the key factor in this QTL affecting PHEV accumulation in tomato fruit., Significance Statement In commercial tomato breeding, elite breeding lines remain the major source of new cultivars. We studied the sensorial, chemical and genetic components of fruit flavor in a collection of commercial glasshouse tomatoes. The haplotypes associated with the flavor QTLs characterized in this study were well represented in the current breeders’ germplasm. Fine mapping of the major QTLs for floral phenolic volatiles resulted in the identification and functional confirmation of the causal gene.

Fruit flavor and nutritional characteristics are key quality traits and ones of the main factors influencing consumer preference. Central carbon metabolism, also known as primary metabolism, contributes to the synthesis of intermediate compounds that act as precursors for plant secondary metabolism. Specific and specialized metabolic pathways that evolved from primary metabolism play a key role in the plant's interaction with its environment. In particular, secondary metabolites present in the fruit serve to increase its attractiveness to seed dispersers and to protect it against biotic and abiotic stresses. As a consequence, several important organoleptic characteristics, such as aroma, color, and fruit nutritional value, rely upon secondary metabolite content. Phenolic and terpenoid compounds are large and diverse classes of secondary metabolites that contribute to fruit quality and have their origin in primary metabolic pathways, while the delicate aroma of ripe fruits is formed by a unique combination of hundreds of volatiles that are derived from primary metabolites. In this review, we show that the manipulation of primary metabolism is a powerful tool to engineer quality traits in fruits, such as the phenolic, terpenoid, and volatile content. The enzymatic reactions responsible for the accumulation of primary precursors are bottlenecks in the transfer of metabolic flux from central to specialized metabolism and should be taken into account to increase the yield of the final products of the biosynthetic pathways. In addition, understanding the connection and regulation of the carbon flow between primary and secondary metabolism is a key factor for the development of fruit cultivars with enhanced organoleptic and nutritional traits.

Durian is one of the most popular fruits in Indonesia. The fruit that has a distinctive taste and aroma is very popular with most people. The sweet fruit flavor and the fragrant aroma of the fruit are the main attraction for durian lovers. The color of the flesh varies, some are white, yellow, and orange and the fruit is complemented by the presence of calories, vitamins, fat and protein. During this time, the part of durian fruit that is more commonly consumed is the portion of the fruit consumed. If you look at the usefulness of durian, it turns out that not only the flesh is consumed, but if explored more deeply can be found a variety of benefits from all parts of the durian fruit such as durian skin parts. Processing of durian skin waste which will later be used as bio-batteries as alternative energy provide a real contribution in realizing the development of science and technology, especially the method of processing durian skin waste into bio-batteries. Not only limited to the processing of durian skin waste will be a useful source of information in the effort to use durian skin waste, so that local people can use it and can be used as an alternative solution to overcome the energy crisis by using bio-batteries as renewable energy that is environmentally friendly. Durian skin waste treatment is expected to create a process of processing durian skin into bio-batteries which will later become an alternative energy that is a solution to overcome the energy crisis by using bio-batteries as environmentally friendly renewable energy, where the results of this study will be very useful for the community. Keywords : Bio- battery , Durian Skin Waste

There are two steps (alcoholic fermentation and acetic acid fermentation) in the production of fruit vinegar by liquid fermentation. The yeast alcoholic fermentation step plays an important role in the quality of apple vinegar. In this work, Candida tropicalis and aromatizing yeast were used in mixed alcoholic fermentation to improve the flavor of the apple vinegar. The total organic acid contents of apple cider and vinegar in mixed cultures were all higher than those in pure culture (Candida tropicalis). Umami and sweet free amino acid levels in mixed-culture apple vinegar (MCAV; 1236.71 and 858.25 mg/L, respectively) were significantly higher than those in pure-culture apple vinegar (PCAV; 1214.69 and 820.37 mg/L, respectively). The total esters, total alcohols, and total phenolics were also significantly increased in MCAV (282.36 g/L, 254.22 g/L and 47.49 g/L, respectively), fruit flavor and floral aromas in MCAV were higher than that in PCAV. In the principal component analysis (PCA), the integrative score for MCAV was higher than that for PCAV. Therefore, mixed cultures of Candida tropicalis and aromatizing yeast in alcoholic fermentation can effectively improve the flavor and quality of apple cider vinegar; more details about the mixed culture need to be investigated in the future.

Papaya (Carica papaya L.) fruit are consumed worldwide, but they are highly perishable. The effects of the application of 1-methylcyclopropene (1-MCP) with and without ethylene on 'Golden' papaya ripening and production of volatile compounds responsible for aroma. Fruit were treated with 2.5 μl L−1 ethylene and/or 100 nL L−1 of 1-MCP for 12 h as follows: I) control, II) ethylene, III) 1-MCP, IV) ethylene + 1-MCP (simultaneous), V) ethylene followed by application of 1-MCP at a 12 h interval and VI) ethylene + 1-MCP without any interval. Pulp firmness, skin color, skin chlorophyll content, skin and pulp carotenoids, ethylene production, respiratory activity, internal ethylene concentration (IEC), pectin methyl esterase (PME) activity, 1-carboxylic acid-1-aminocyclopropane oxidase (ACC oxidase) activity and volatile compounds were measured. Fruit were stored at 22 °C, with analysis of volatile compounds performed until day 8 and all others until day 6. Fruit treated with only 1-MCP developed rubberized pulp. Fruit treated simultaneously with ethylene and 1-MCP reached desirable firmness for consumption by day 6. Co-application of 1-MCP + ethylene promoted chlorophyll degradation. A consistent increase in ethylene production in 1-MCP-treated fruit above those observed in control fruit and in fruit treated with ethylene only was observed. In relation to volatile compounds, linalool and its oxides were affected less by 1-MCP treatment, with or without ethylene, on days 2 and 6, and did not affect fruit flavor.

It is generally believed that domestication and breeding of plants has led to genetic erosion, including loss of nutritional value and resistances to diseases, especially in tomato. We studied the diversity dynamics of greenhouse tomato varieties in NW Europe, especially The Netherlands, over the last seven decades. According to the used SNP array, the genetic diversity was indeed very low during the 1960s, but is now eight times higher when compared to that dip. The pressure since the 1970s to apply less pesticides led to the introgression of many disease resistances from wild relatives, representing the first boost of genetic diversity. In Europe a second boost ensued, largely driven by German popular media who named poor tasting tomatoes Wasserbomben (water bombs). The subsequent collapse of Dutch tomato exports to Germany fueled breeding for fruit flavor, further increasing diversity since the 1990s. The increased diversity in composition of aroma volatiles observed starting from 1990s may reflect the efforts of breeders to improve fruit quality. Specific groups of aroma compounds showed different quantitative trend over the decades studied. Our study provides compelling evidence that breeding has increased the diversity of tomato varieties considerably since the 1970s.

Products that will be prepared by consumers must be tolerant to various cooking procedures that those consumers may use. Fortified blended foods (FBFs) are used as a source of nutrition for disaster or famine relief in developing countries. Many FBFs are served as porridge and may have a wide of solids content, cooking times and variations in added ingredients. Sorghum is being examined as a potential alternative to wheat and corn based FBF products. This study was intended to evaluate the tolerance to preparation variations for porridge made as a FBF intended for food aid. Whole Sorghum Soy Blend (WSSB), a fortified, extruded, ground cooked cereal was selected as the FBF for this study. Descriptive sensory analysis and Bostwick flow rate measurements were performed to evaluate the tolerance of porridge products made from variations in ingredients and cooking procedures. The results showed that most sensory properties were only marginally affected although some expected large differences in a few sensory properties were found when solids content varied (that is, thickness, adhesiveness) or fruit (banana flavor) was added. Moreover, Bostwick flow rate was a reasonable indicator of thickness characteristics of porridges in some cases, but not in others. Tolerance testing showed that the sensory properties of WSSB had high tolerance to variations in cooking procedures, which means that the product can be modified during preparation by consumers without having a major impact on most sensory properties other than ones they intended to change such as thickness, sweetness, or fruit flavor. Practical Application The results from this study showed that porridge products from whole sorghum soy blend had high sensory tolerance to preparation variations. Thus, this product can be used by diverse people in diverse conditions.

The phenolic composition, aroma, and sensory profiles were evaluated for Pinot noir wines made using four different maceration techniques that modified the floating pomace cap during fermentation: 1) daily plunging; 2) reduced skin particle size (accentuated cut edges, ACE); 3) submerged cap; and 4) ACE plus submerged cap. Throughout vinification, wines were analyzed using rapid analytical techniques to assess the following phenolic attributes: anthocyanin, tannin, nonbleachable pigments, color density, and hue. At six months bottle age (230 days postinoculation), sensory and aroma analyses were conducted on the finished wines. ACE macerated wines were found to have the highest proportion of red color, tannin, nonbleachable pigments, fruit and floral aromas, bitterness, and astringency. Submerging the pomace cap resulted in a lower concentration of phenolic components when compared to ACE wines, but resulted in a significantly higher phenolic content and dark cherry aromas and flavor when compared to the control wine. These findings suggest that the employment of either maceration technique has the potential to make a considerable difference to the wine style produced from a given parcel of fruit and may provide an opportunity to press wines earlier in the fermentation. Linear regression analyses were conducted to compare descriptive wine parameters with instrumental phenolic measurements and demonstrated several strong correlations: red color appearance was correlated with both color density (r2 = 0.95) and nonbleachable pigment (r2 = 0.95); dark fruit flavor was correlated with both color density (r2 = 0.85) and nonbleachable pigment (r2 = 0.85); and astringency was correlated with both tannin (r2 = 0.97) and nonbleachable pigment (r2 = 0.87), demonstrating that techniques of rapid chemical analysis were able to provide valuable insights into the sensory properties of the wine and may become useful tools for monitoring the development of the wine during vinification. While submerged cap vinification also increased the tannin and nonbleachable pigment profiles of the wine, ACE maceration was found to be significantly more effective and is likely to be more readily adapted for application in commercial wineries.

Refrigeration is the main postharvest technology for increasing shelf life of horticultural products; however, it has a detrimental effect on tomato ( Solanum lycopersicum ) flavor. The objective of the present study was to evaluate the effect of refrigerated storage at 12.5 °C on tomato aroma profile, sensory quality, and consumer’s flavor perception. C6 and 3-methyl butanol volatile levels were determined by GC. Enzyme activity and gene expression of alcohol dehydrogenase (ADH) and lipoxygenase (LOX), involved in the oxylipin biosynthetic pathway were also determined. A quantitative descriptive analysis (QDA) and a consumer test were carried out to compare the effect of refrigerated storage on flavor perception at 10 °C and 12.5 °C to non-refrigerated tomatoes. Refrigerated storage at 12.5 °C caused a general decrease on total aroma volatiles that were detected from 9 d onward. A lack of accumulation of hexanal, hexanol and cis -3-hexenol, a transitory increase of trans -2-hexenol and the accumulation of 3-methyl butanol were observed. Trained judges perceived these changes as an increase of the musty/damp descriptor which was higher in fruit stored at 10 °C than at 12.5 °C. Tomatoes stored at 10 °C were the less preferred by consumers perceived as less fresh and with the presence of off odors. Consumers did not find differences between tomato stored at 12.5 °C and 20 °C. Results showed that tomato fruit stored at 12.5 °C maintain a better sensory quality than those stored at 10 °C.