Fruit Quality Control Research Articles

Cracking of jujube fruits is associated with differential expression of metabolic genes.

Cracks in the skin of jujube fruit reduce freshness and quality; thus, greater understanding of the molecular mechanism that underlies cracking is required to improve fruit production. In this study, we profiled genes that are differentially expressed between cracked and normal jujube fruits through RNA sequencing (RNA-seq). We selectively confirmed differentially expressed genes (DEGs) using quantitative RT-PCR. Among 1036 DEGs, 785 genes were up-regulated and 251 genes were down-regulated in cracked jujube fruits. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that some of these DEGs encode proteins involved in metabolic processes (including growth hormone and surface wax production) in cracked jujube fruits. In summary, we have identified differentially expressed metabolic genes between cracked and normal jujube fruits, which may serve as the basis for further studies of fruit quality control.

Characterization of a Multispectral Imaging System Based on Narrow Bandwidth Power LEDs

Multispectral imaging systems using narrow-band power LEDs have become a feasible solution for a wide range of applications. Their fast response and simple implementation compensate for a low spectral resolution. In this article, we are filling a gap identified in the literature on multispectral systems by presenting a detailed design of a light controller, as well as a characterization of the whole system by means of a correlation and a repeatability analysis. We use a reference color target to assess accuracy and precision by comparing our system with high-performance hyperspectral equipment used in fruit quality control. The system captures multispectral images (MSIs) with 15 different wavelengths ( $\lambda \in [410~950$ ] nm). The main finding is a Pearson correlation index above 80% ( $\rho > 0.8$ ) with a variance in the measure within 10% ( $\sigma ^{2} ). We also examine the characteristics of the instrument at a maximum speed of 8 MSIs/s although this entails sacrificing precision ( $\sigma ^{2} ).

Transcriptomic analysis reveals hub genes and subnetworks related to ROS metabolism in Hylocereus undatus through novel superoxide scavenger trypsin treatment during storage

BackgroundIt was demonstrated in our previous research that trypsin scavenges superoxide anions. In this study, the mechanisms of storage quality improvement by trypsin were evaluated in H. undatus.ResultsTrypsin significantly delayed the weight loss and decreased the levels of ROS and membrane lipid peroxidation. Transcriptome profiles of H. undatus treated with trypsin revealed the pathways and regulatory mechanisms of ROS genes that were up- or downregulated following trypsin treatment by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses. The current results showed that through the regulation of the expression of hub redox enzymes, especially thioredoxin-related proteins, trypsin can maintain low levels of endogenous active oxygen species, reduce malondialdehyde content and delay fruit aging. In addition, the results of protein-protein interaction networks suggested that the downregulated NAD(P) H and lignin pathways might be the key regulatory mechanisms governed by trypsin.ConclusionsTrypsin significantly prolonged the storage life of H. undatus through regulatory on the endogenous ROS metabolism. As a new biopreservative, trypsin is highly efficient, safe and economical. Therefore, trypsin possesses technical feasibility for the quality control of fruit storage.Graphical abstract

Heterotic Potential, Potence Ratio, Combining Ability and Genetic Control of Quality and Yield Traits in Bell Pepper Under Net-House Conditions of NW Himalayas

The present experiment was carried out with the aim of identifying outstanding specific combiners and best parental lines along with the understanding of genetic control of fruit quality and yield traits of bell pepper under net-house conditions in northwestern Himalayas of India. Eight inbred lines were crossed in half diallel manner, and the resulted twenty-eight F1 hybrids along with a standard check variety were evaluated under net-house conditions. California Wonder and Solan Bharpur parental lines were found to be the best combiner for earliness, whereas Yolo Wonder, California Wonder, Nishath-1 and UHFBP-3 reported as best parental line for fruit quality, yield and yield contributing traits based on their general combining effects. Solan Bharpur × Yolo Wonder, Yolo Wonder × Nishath-1, California Wonder × Solan Bharpur, California Wonder × UHFBP-3 and UHFBP-3 × KC-12 cross-combinations found outstanding based on heterosis and specific combining ability for most of the traits under net-house condition. The present studied hybrids illustrated the presence of over-dominance effect for yield and yield contributing traits under study. Predominance of nonadditive gene action for all the characters suggested the usefulness of exploitation of hybrid vigor.

Quality of fruits of pitaya (Hylocereus undatus [Haworth] Britton & Rose) according to physiological maturity. A review

The fruit of pitaya has occupied a growing niche in the fruit market, since its organoleptic characteristics and rusticity have attracted the attention of consumers and producers, respectively. The organoleptic and nutritional quality of fruits are due to maturity stage. Therefore, determining the period in which the fruits reach the physiological maturity is important, since it aids the planning of the harvest and the quality control of fruits. In this sense, the aim of this review is establish the ideal period for harvesting their fruits of pitaya (Hylocereus undatus), by determining of the physiological maturity point. For this species, the number of days from anthesis to the full development of the fruit has shown to be the most reliable variable to determine the moment of harvest. From this designation, it is possible to indicate the stage (physiological maturity) in which the fruits present characteristics favorable to the species, for example, color, soluble solids content, ratio, and others. It is known that the place of production and the edaphoclimatic conditions are able to interfere and cause variation in the period in which the fruits reach the physiological maturity. Some studies in Mexico confirmed that the physiological maturation of pitaya fruits occurred between 25 and 31 days after anthesis (DAA). Other researches, including in Brazil, confirmed that this point occurred from 28 to 32 DAA. Thus, from the scientific studies carried out and published in the literature, to avoid losing their commercial value of fruits, it is recommended to harvest this fruits of pitaya between 25 and 32 DAA.

OTIMIZAÇÃO DO PROCESSO NÃO INVASIVO E NÃO DESTRUTIVO DE EXTRAÇÃO E ANÁLISE DE METABÓLITOS VOLÁTEIS DE MAMÃO PAPAIA POR SPME-GC-MS

Abstract: The analysis of volatiles is an alternative in the routine of quality control of fruits, since the volatile metabolites can change in the presence of microorganisms. A well-established method for extracting volatiles is the solid phase microextraction (SPME). This work aims to define some parameters (fiber coating, conditioning time and fiber exposure time) for an effective extraction. Whole papaya was inserted into a hermetically closed glass bottle and the system was left in conditioning for the volatiles accumulation. Then, extraction by SPME and subsequent desorption in a gas chromatograph was performed. Two fibers were evaluated: a 100 μm polydimethylsiloxane (PDMS) and a 65 μm polydimethylsiloxane/divinylbenzene (PDMS/DVB). The PDMS/DVB fiber extracted the highest number of volatiles. Central composite design (CCD) was performed to assess the effect of papaya conditioning time and the fiber exposure time on the response: number of detectable peaks. Both variables studied and their interactions were significant for the response. ANOVA showed that the quadratic terms and the lack of fit were not significant (p <0.05). A conditioning time of 10 min and exposure time of 30 min was sufficient for the detection of more than 100 compounds.

INTELLIGENT SYSTEM FOR AUTOMATIC CLASSIFICATION OF FRUIT DEFECT USING FASTER REGION-BASED CONVOLUTIONAL NEURAL NETWORK (FASTER R-CNN)

In 2018, the Indonesian fruit exports increased by 24% from the previous year. The surge in demand for tropical fruits from non-tropical countries is one of the contributing factors for this trend. Some of these countries have strict quality requirements – the poor level quality control of fruit is an obstacle in achieving greater export yield. This is because some exporters still use manual sorting processes performed by workers, hence the quality standard varies depending on the individual perception of the workers. Therefore, we need an intelligent system that is capable of automatic sorting according to the standard set. In this research, we propose a system that can classify fruit defects automatically. Faster R-CNN (FRCNN) architecture proposed as a solution to detect the level of defect on the surface of the fruit. There are three types of fruit that we research, its mangoes (sweet fragrant), lime, and pitaya fruit. Each fruit divided into three categories (i) Super, (ii) middle, (iii) and fruit defects. We exploit join detection and video tracking to calculate and determine the quality fruit in real-time. The datasets are taken in the field, then trained using the FRCNN Framework using the Tensorflow platform. We demonstrated that this system can classify fruit with an accuracy level of 88% (mango), 83% (lime), and 99% (pitaya), with an average computation cost of 0.0131 m/s. We can track and calculate fruit sequentially without using additional sensors and check the defect rate on fruit using the video streaming camera more accurately and with greater ease.

Ethephon and fosetyl residues in fruits from São Francisco Valley, Brazil

ABSTRACTThis survey describes the occurrence of Ethephon (ETH) and Fosetyl in fruits intended for export produced in the São Francisco Valley, Brazil. The determination of these compounds was carried out by the QuPPe-method (Quick Polar Pesticides Method), which was optimised and successfully validated according to the SANTE/11813/2017. From January 2016 to December 2018 a total of 1048 samples were analysed for ETH residues. In 547 (53%) of the samples, residues below the EU MRL of 1 mg kg−1 were present. In 17 samples (2%) ETH residues were above 1 mg kg−1. Overall, the mean ETH level decreased after 2016. Analyses of fosetyl showed that (18%) of 109 mango samples were positive for this compound. Phosphonic acid was found in concentrations ranging from 0.12 to 3.2 mg kg−1 and 5% of the measurements were above the EU MRL of 2 mg kg−1. The results emphasise the quality control of fruits produced in this region.

Recent advances in ultrasound application as a novel technique in analysis, processing and quality control of fruits, juices and dairy products industries: A review

Recently, ultrasound has been widely used in the researches in the food science and technology. Among the food materials, fruits, juices and dairy products are strongly sensitive to ultrasound-based techniques. In this review paper, applications of ultrasound in terms of high and low-power modes in processing, instrumentation and control of the industrial operations are studied in the fruit, juice and dairy sectors of the food science and technology by emphasizing the principles of these techniques and their physicochemical effects on the products. Also, a comprehensive analysis of these methods and important factors influencing their performance are presented, along with the advantages and the drawbacks of each ultrasound-assisted techniques. The solutions for better productivity of this technique would be presented and future trend of this technology would be outlined. By studying the latest researches and advances in the field of ultrasound applications, it has been confirmed that this technique can be helpful in accelerating processes, reducing energy requirements, increasing productivity, and producing better quality food materials in the fields of fruits, juices and dairy products. Notwithstanding, in order to solve the challenges ahead, and for potential applications of ultrasound technology, further researches need to be expanded in the areas mentioned. Also, with the advancement of technology, more advanced equipment, ultrasound transducers and instrumentations would be introduced that needs to be applied in this regard, to solve the current challenges.

QTL mapping of melon fruit quality traits using a high-density GBS-based genetic map

BackgroundMelon shows a broad diversity in fruit morphology and quality, which is still underexploited in breeding programs. The knowledge of the genetic basis of fruit quality traits is important for identifying new alleles that may be introduced in elite material by highly efficient molecular breeding tools.ResultsIn order to identify QTLs controlling fruit quality, a recombinant inbred line population was developed using two commercial cultivars as parental lines: “Védrantais”, from the cantalupensis group, and “Piel de Sapo”, from the inodorus group. Both have desirable quality traits for the market, but their fruits differ in traits such as rind and flesh color, sugar content, ripening behavior, size and shape. We used a genotyping-by-sequencing strategy to construct a dense genetic map, which included around five thousand variants distributed in 824 bins. The RIL population was phenotyped for quality and morphology traits, and we mapped 33 stable QTLs involved in sugar and carotenoid content, fruit and seed morphology and major loci controlling external color of immature fruit and mottled rind. The median confidence interval of the QTLs was 942 kb, suggesting that the high density of the genetic map helped in increasing the mapping resolution. Some of these intervals contained less than a hundred annotated genes, and an integrative strategy combining gene expression and resequencing data enabled identification of candidate genes for some of these traits.ConclusionSeveral QTLs controlling fruit quality traits in melon were identified and delimited to narrow genomic intervals, using a RIL population and a GBS-based genetic map.

A critical evaluation of the role of ethylene and MADS transcription factors in the network controlling fleshy fruit ripening.

Contents Summary 1724 I. Introduction 1725 II. Ripening genes 1725 III. The importance of ethylene in controlling ripening 1727 IV. The importance of MADS-RIN in controlling ripening 1729 V. Interactions between components of the ripening regulatory network 1734 VI. Conclusions 1736 Acknowledgements 1738 Author contributions 1738 References 1738 SUMMARY: Understanding the regulation of fleshy fruit ripening is biologically important and provides insights and opportunities for controlling fruit quality, enhancing nutritional value for animals and humans, and improving storage and waste reduction. The ripening regulatory network involves master and downstream transcription factors (TFs) and hormones. Tomato is a model for ripening regulation, which requires ethylene and master TFs including NAC-NOR and the MADS-box protein MADS-RIN. Recent functional characterization showed that the classical RIN-MC gene fusion, previously believed to be a loss-of-function mutation, is an active TF with repressor activity. This, and other evidence, has highlighted the possibility that MADS-RIN itself is not important for ripening initiation but is required for full ripening. In this review, we discuss the diversity of components in the control network, their targets, and how they interact to control initiation and progression of ripening. Both hormones and individual TFs affect the status and activity of other network participants, which changes overall network signaling and ripening outcomes. MADS-RIN, NAC-NOR and ethylene play critical roles but there are still unanswered questions about these and other TFs. Further attention should be paid to relationships between ethylene, MADS-RIN and NACs in ripening control.

Quantitative proteomic analysis reveals the involvement of mitochondrial proteins in tomato fruit ripening

Fruit ripening is characterized by dramatic changes in fruit quality and is considered to influence postharvest storage. The mitochondria are one of the most important organelles that play crucial roles in fruit quality formation, but the underlying mechanisms remain unclear. In this study, the expression profiles of mitochondrial proteins during tomato fruit ripening were investigated using quantitative proteomic analysis, leading to the identification of 27 proteins which showed altered abundance. We additionally evaluated changes in the mitochondrial proteome in the ripening-deficient mutant, ripening-inhibitor (rin), which carries a mutation in the transcription factor RIN. A total of 74 proteins were identified which changed abundance significantly in the rin mutant. Gene expression analysis combined with chromatin immunoprecipitation indicated that four genes, DnaK, HSP, PYP, and ACC, which encode chaperone DnaK, heat shock protein, pyruvate kinase, and acetyl-CoA carboxylase, respectively, are direct targets of RIN. These results suggest that mitochondria might participate in the regulation of fruit quality and ripening by specific proteins. Our findings provide new information to unravel of gene regulatory networks that control fruit quality and ripening.

Marker-assisted pyramiding of quantitative trait loci controlling fruit quality traits in tomato

Tomato consumption is considered fundamental for human health for its high nutritional value, mainly ascribed to antioxidant metabolites. In the last few years, we have focused our research on deciphering the genetic control of antioxidant compounds in tomato fruits and to produce superior genetic materials with an increased amount of bioactive compounds in the red ripe berry. For this purpose, we used introgression lines (ILs) obtained from the wild species Solanum pennellii, and we selected lines IL7-3 and IL12-4 for their high content of hydrophilic antioxidants in the fruit. These lines were crossed to combine the identified quantitative trait loci (QTLs) and obtain superior hybrids. A set of species-specific molecular markers was used to clearly distinguish the wild S. pennellii from the cultivated Solanum lycopersicum genome. In the present work, we describe the selection of one double homozygous hybrid (DHO22) and its multilevel characterization in comparison with its parental genotypes and with the cultivated genotype M82. The selected hybrid DHO22 exhibits high contents of ascorbic acid and phenolics, combined with good performances in terms of yield and other fruit quality traits, and clearly resembles the cultivated genotype M82. In future, this line could be used as pre-breeding material to obtain a new cultivar improved for nutritional traits.

Comparative Analysis of SSR Markers Developed in Exon, Intron, and Intergenic Regions and Distributed in Regions Controlling Fruit Quality Traits in Prunus Species: Genetic Diversity and Association Studies

Simple sequence repeats (SSRs) are genome domains located in both coding and non-coding regions in eukaryotic genomes. Although SSRs are often characterized by low polymorphism, their DNA-flanking sequences could be a useful source of DNA markers, which could help in genetic studies and breeding because they are associated with genes that control traits of interest. In this study, 56 genotypes from different Prunus species were used, including peach, apricot, plum, and almond (already phenotyped for several agronomical traits, including self-compatibility, flowering and ripening time, fruit type, skin and flesh color, and shell hardness). These Prunus genotypes were molecularly characterized using 28 SSR markers developed in exons, introns, and intergenic regions. All these genes were located in specific regions where quantitative trait loci (QTLs) for certain fruit quality traits were also located, including flowering and ripening times and fruit flesh and skin color. A sum of 309 SSR alleles were identified in the whole panel of analyzed cultivars, with expected heterozygosity values of 0.61 (upstream SSRs), 0.17 (exonic SSRs), 0.65 (intronic SSRs), and 0.58 (downstream SSRs). These values prove the low level of polymorphism of the exonic (gene-coding regions) markers. Cluster and structural analysis based on SSR data clearly differentiated the genotypes according to either specie (for the four species) and pedigree (apricot) or geographic origin (Japanese plum). In addition, some SSR markers mainly developed in intergenic regions could be associated with genes that control traits of interest in breeding and could therefore help in marker-assisted breeding. These findings highlight the importance of using molecular markers able to discriminate between the functional roles of the gene allelic variants.

Reduced representation genome sequencing reveals patterns of genetic diversity and selection in apple.

Identifying DNA sequence variations is a fundamental step towards deciphering the genetic basis of traits of interest. Here, a total of 20 cultivated and 10 wild apples were genotyped using specific-locus amplified fragment sequencing, and 39,635 single nucleotide polymorphisms with no missing genotypes and evenly distributed along the genome were selected to investigate patterns of genome-wide genetic variations between cultivated and wild apples. Overall, wild apples displayed higher levels of genetic diversity than cultivated apples. Linkage disequilibrium (LD) decays were observed quite rapidly in cultivated and wild apples, with an r2 -value below 0.2 at 440 and 280 bp, respectively. Moreover, bidirectional gene flow and different distribution patterns of LD blocks were detected between domesticated and wild apples. Most LD blocks unique to cultivated apples were located within QTL regions controlling fruit quality, thus suggesting that fruit quality had probably undergone selection during apple domestication. The genome of the earliest cultivated apple in China, Nai, was highly similar to that of Malus sieversii, and contained a small portion of genetic material from other wild apple species. This suggested that introgression could have been an important driving force during initial domestication of apple. These findings will facilitate future breeding and genetic dissection of complex traits in apple.

Cover Caption: Apple genetic variation and selection

Wild apples display higher levels of genetic diversity than cultivated apples. In this issue, Ma et al. (190–204) observed linkage disequilibrium (LD) decays quite rapidly in cultivated and wild apples. Most LD blocks unique to cultivated apples are located within QTL regions controlling fruit quality, suggesting that fruit quality has undergone selection during domestication. Introgression is also an important driving force during initial domestication. The wild apple photo is provided by Cuiying Li from Northwest A&amp;F University.

Prediction of the level of astringency in persimmon using visible and near-infrared spectroscopy

Early control of fruit quality requires reliable and rapid determination techniques. Therefore, the food industry has a growing interest in non-destructive methods such as spectroscopy. The aim of this study was to evaluate the feasibility of visible and near-infrared (NIR) spectroscopy, in combination with multivariate analysis techniques, to predict the level and changes of astringency in intact and in the flesh of half cut persimmon fruits. The fruits were harvested and exposed to different treatments with 95% CO2 at 20 °C for 0, 6, 12, 18 and 24 h to obtain samples with different levels of astringency. A set of 98 fruits was used to develop the predictive models based on their spectral data and another external set of 42 fruit samples was used to validate the models. The models were created using the partial least squares regression (PLSR), support vector machine (SVM) and least squares support vector machine (LS-SVM). In general, the models with the best performance were those which included standard normal variate (SNV) in the pre-processing. The best model was the PLSR developed with SNV along with the first derivative (1-Der) pre-processing, created using the data obtained at six measurement points of the intact fruits and all wavelengths (R2 = 0.904 and RPD = 3.26). Later, a successive projection algorithm (SPA) was applied to select the most effective wavelengths (EWs). Using the six points of measurement of the intact fruit and SNV together with the direct orthogonal signal correction (DOSC) pre-processing in the NIR spectra, 41 EWs were selected, achieving an R2 of 0.915 and an RPD of 3.46 for the PLSR model. These results suggest that this technology has potential for use as a feasible and cost-effective method for the non-destructive determination of astringency in persimmon fruits.

Recent Developments in Methods and Techniques for Rapid Monitoring of Sugar Metabolism in Fruits.

The major sugars in fruits, including glucose, fructose, and sucrose, play a critical role in fruit quality control and maturity evaluation. Many novel methods and techniques such as enzymatic and nonenzymatic biosensors, nuclear magnetic resonance, and near-infrared spectroscopy have been developed to provide the rapid estimation of sugar inversion under different storage conditions. This review provides a description of recent advancements in these technologies for the determination of sugar contents in fruits. The prospects of emerging spectroscopic technologies such as Raman spectroscopy, hyperspectral imaging, and terahertz imaging, for assessing sugars in intact fruits are discussed. The challenges for further developments of these methods and technologies to meet the increasing demand for rapid and on-line quality control are also presented.

Functional characterization of a chemical defoliant that activates fruit cluster Leaf defoliation in ‘Fuji’ apple trees

The removal of fruit cluster leaves was shown to be a valuable method for controlling fruit quality and producing high-grade apples. A chemical defoliant that functions as an activation switch was shown to turn on the genes necessary for fruit cluster leaf defoliation. Elucidating the mechanism involved in leaf defoliation is crucial to our understanding of the use of chemical defoliants in fruit trees. To gain insight into chemical defoliant-mediated leaf defoliation, we first confirmed the occurrence of ethylene production by applying a chemical defoliant on fruit cluster leaves. Then, we used RNA-seq analysis to obtain a series of transcriptome profiles for genes and proteins involved in leaf senescence induction. Within 2 days of applying the chemical defoliant to apple trees, 1-aminocyclopropane carboxylic acid (ACC) oxidase, ACC synthase, a chlorophyll binding protein, and polygalacturonase-related genes were up-regulated at least sixfold. An in vitro enzyme assay showed that lanolin oil activates ACC synthase activity, a key regulatory enzyme in the ethylene pathway. We also showed that chemical defoliant decreased the light saturation point and total chlorophyll content. Then, we used a polygalacturonase activity assay to confirm the effects of chemical defoliant on leaf senescence in vivo. Furthermore, treatment with chemical defoliant resulted in a significant increase in the chromaticity value of a*, whereas L* and b* decreased in the apple fruit. Taken together, we conclude that chemical defoliant could selectively affect fruit cluster leaves, which suggested that it can be used as a selective defoliant.

Mapping QTLs associated with fruit quality traits in peach [Prunus persica (L.) Batsch] using SNP maps

Fruit quality is an essential criterion used to select new cultivars in peach breeding programs and is determined based on a combination of organoleptic and nutritional traits. The aim of this study was to identify quantitative trait loci (QTLs) for fruit quality traits in an F1 nectarine population derived from ‘Venus’ and ‘Big Top’ cultivars. The progeny were evaluated over 4 years for agronomical and biochemical characteristics and genotyped using simple sequence repeat (SSR) markers and ‘IPSC 9K peach SNP array v1’. Two genetic maps were constructed using 411 markers. The ‘Venus’ map spanned 259 cM on nine linkage groups (LGs) with 104 markers. The ‘Big Top’ map spanned 464 cM on 10 LGs with 122 markers. Single or Multiple QTL models mapping was applied separately for each year and all years combined. A total of 54 QTLs mapped over 12 LGs belonged to seven peach chromosomes. Most of the QTLs were consistent over the 4 years of study and were validated with the multi-year analysis. QTLs for total phenolic, flavonoid, and anthocyanin contents were reported for the first time in peach. LG 4 in ‘Venus’ and LG 5 in ‘Big Top’ showed the highest numbers of QTLs. This work represents the first study in an F1 nectarine family to identify peach genomic regions that control fruit quality traits using ‘IPSC 9K SNP array v1’ and provides useful information for marker-assisted breeding to produce peaches with better antioxidant content and healthy attributes.