Exocarp Color Research Articles

Integrated transcriptomics and metabolomics analyses of the effects of bagging treatment on carotenoid biosynthesis and regulation of Areca catechu L.

Fresh Aareca nut fruit for fresh fruit chewing commonly found in green or dark green hues. Despite its economic significance, there is currently insufficient research on the study of color and luster of areca. And the areca nut fruits after bagging showed obvious color change from green to tender yellow. In the study, we tried to explain this interesting variation in exocarp color. Fruits were bagged (with a double-layered black interior and yellow exterior) 45 days after pollination and subsequently harvested 120 days after pollination. In this study, we examined the the chlorophyll and carotenoid content of pericarp exocarp, integrated transcriptomics and metabolomics to study the effects of bagging on the carotenoid pathway at the molecular level. It was found that the chlorophyll and carotenoid content of bagged areca nut (YP) exocarp was significantly reduced. A total of 21 differentially expressed metabolites (DEMs) and 1784 differentially expressed genes (DEGs) were screened by transcriptomics and metabolomics. Three key genes in the carotenoid biosynthesis pathway as candidate genes for qPCR validation by co-analysis, which suggested their role in the regulation of pathways related to crtB, crtZ and CYP707A. We described that light intensity may appear as a main factor influencing the noted shift from green to yellow and the ensuing reduction in carotenoid content after bagging.

Identification and Characterization of ABCG15-A Gene Required for Exocarp Color Differentiation in Pear.

Exocarp color is a commercially essential quality for pear which can be divided into two types: green and russet. The occurrence of russet color is associated with deficiencies and defects in the cuticular and epidermal layers, which affect the structure of the cell wall and the deposition of suberin. Until now, the genetic basics triggering this trait have not been well understood, and limited genes have been identified for the trait. To figure out the gene controlling the trait of exocarp color, we perform a comprehensive genome-wide association study, and we describe the candidate genes. One gene encoding the ABCG protein has been verified to be associated with the trait, using an integrative analysis of the metabolomic and transcriptomic data. This review covers a variety of omics resources, which provide a valuable resource for identifying gene-controlled traits of interest. The findings in this study help to elucidate the genetic components responsible for the trait of exocarp color in pear, and the implications of these findings for future pear breeding are evaluated.

ABA Biosynthesis- and Signaling-Related Gene Expression Differences between Sweet Cherry Fruits Suggest Attenuation of ABA Pathway in Bicolored Cultivars.

Fruit development involves exocarp color evolution. However, signals that control this process are still elusive. Differences between dark-red and bicolored sweet cherry cultivars rely on MYB factor gene mutations. Color evolution in bicolored fruits only occurs on the face receiving sunlight, suggesting the perception or response to color-inducing signals is affected. These color differences may be related to synthesis, perception or response to abscisic acid (ABA), a phytohormone responsible for non-climacteric fruit coloring. This work aimed to determine the involvement of ABA in the coloring process of color-contrasting varieties. Several phenolic accumulation patterns differed between bicolored 'Royal Rainier' and dark-red 'Lapins'. Transcript abundance of ABA biosynthetic genes (PavPSY, PavZEP and PavNCED1) decreased dramatically from the Pink to Red stage in 'Royal Rainier' but increased in 'Lapins', which correlated with a higher ABA content in this dark-red cultivar. Transcripts coding for ABA signaling (PavPP2Cs, PavSnRKs and PavMYB44.1) were almost undetectable at the Red stage in 'Royal Rainier'. Field trials revealed that 'Royal Rainier' color development was insensitive to exogenous ABA, whereas it increased in 'Lapins'. Furthermore, ABA treatment only increased transcript levels of signaling genes in 'Lapins'. Further studies may address if the ABA pathway is attenuated in bicolor cultivars.

AUTHENTICATION OF THREE WAX APPLES CULTIVARS (SYZYGIUM SAMARANGENSE (BLUME) MERR. & L.M. PERRY) BASED ON MORPHOLOGICAL CHARACTER AND FRUIT METABOLITE PROFILE

Wax apple is one of the superior fruits of Demak, especially cultivars 'Citra', 'Delima' and ‘Madu Deli Hijau'. Research on the wax apple of the three cultivars is still limited. Therefore, research on the authentication of wax apple cultivars based on morphological characters and metabolite profiles present in one location is important to do. The aims of this study were to identify morphological characters and analyze metabolite profiles, to analyze relationship and to identify morphological characters and metabolite marker profiles in the authentication activities of three wax apples cultivars. Sampling was in Boyolali Village, Demak Regency. The stages of this research included morphological characterization of stem, leaf, fruit and seed organs, phylogeny analysis with MVSP, metabolite profile analysis using GC-MS, and determination of morphological characters and metabolite profiles with PCA. The results showed that there were morphological diversity and metabolite profile variations of the three cultivars. Relationship analysis based on morphological characters and metabolite profiles resulted in different grouping patterns. 'Madu Deli Hijau' and 'Citra' are closely related based on morphological characters and a combination of morphological characters and metabolite profiles. Morphological characters in the authentication of the 'Citra' (dark red exocarp color), 'Delima' (bright red exocarp color, smooth and flat fruit surface, jagged fruit shape), in 'Madu Deli Hijau' (elongated leaf shape and exocarp is green with a pink tinge). Authentication of probable marker metabolite profiles on 'Citra', 'Delima' and 'Madu Deli Hijau' wax apples of 10, 7 and 5 compounds.

A multiomics integrative analysis of color de-synchronization with softening of ‘Hass’ avocado fruit: A first insight into a complex physiological disorder

Exocarp color de-synchronization with softening of ‘Hass’ avocado is a relevant recurrent problem for the avocado supply chain. This study aimed to unravel the mechanisms driving this de-synchronization integrating omics datasets from avocado exocarp of different storage conditions and color phenotypes. In addition, we propose potential biomarkers to predict color synchronized/de-synchronized fruit. Integration of transcriptomics, proteomics and metabolomics and network analysis revealed eight transcription factors associated with differentially regulated genes between regular air (RA) and controlled atmosphere (CA) and twelve transcription factors related to avocado fruit color de-synchronization control in ready-to-eat stage. CA was positively correlated to auxins, ethylene, cytokinins and brassinosteroids-related genes, while RA was characterized by enrichment of cell wall remodeling and abscisic acid content associated genes. At ready-to-eat higher contents of flavonoids, abscisic acid and brassinosteroids were associated with color-softening synchronized avocados. In contrast, de-synchronized fruit revealed increases of jasmonic acid, salicylic acid and auxin levels.

Comparative transcriptome profiling and molecular marker development for oil palm fruit color

Oil palm harvesting is normally determined by fruit exocarp color. To detect expressed sequence tag (EST)-simple sequence repeat (SSR) markers in oil palm hybrid populations, de novo transcriptomic profiling of Nigeria black and Suratthani 1 (Deli × Calabar) plants was performed. More than 46 million high-quality clean reads with a mean length of 1117 bp were generated. Functional annotation and gene ontology (GO) enrichment analysis of differentially expressed genes (DEGs) revealed that the genes were involved in fruit color development and pigment synthesis. Comparison of immature/mature DEGs indicated that nigrescent fruit color was driven by the anthocyanin biosynthesis pathway (ABP); however, the carotenoid biosynthesis pathway (CBP) was involved in the color development of both fruit types. The transcripts of both unique and different genes involved in the ABP and CBP in higher plants were highlighted for further study, especially 3GT, downstream genes in the ABP, and DEARF27 in the CBP. Additionally, SSR primer motifs, namely, 9949, discovered from the DEGs upregulated in the virescent type that encode vacuolar iron transporter (VIT), could separate the nigrescence and virescence traits of Nigeria hybrids. This novel primer has potential to be used as a molecular for further selection in breeding programs especially involving the specific genetic backgrounds described in this study.

Effects of a brief blanching process on quality, safety, and shelf life of refrigerated cucumber pickles.

Refrigerated pickles are characterized by crisp, crunchy texture, opaque flesh, and fresh flavor. Typically produced without a thermal process, microbial safety relies on preventive controls, brine composition, and sufficient hold time prior to consumption. We hypothesized that brief blanching of whole cucumbers prior to pickling could provide an additional hurdle for pathogenic microbes without negatively impacting finished product quality. Blanch treatments (15, 90, or 180 s) in 80°C water were conducted in duplicate on two lots of cucumbers prior to cutting into spears, acidifying, and storing at 4°C. Enumeration of total aerobes, lactic acid bacteria, and glucose-fermenting coliforms was conducted for fresh and blanched cucumber. Texture, color, cured appearance development, and volatile compound profiles were analyzed for fresh and blanched cucumber and corresponding pickle products during refrigerated storage. The 90 s blanch consistently achieved a minimum 2-log reduction in cucumber microbiota and a predicted 5-log reduction of Escherichia coli O157:H7 up to 1.1mm into the cucumber fruit. Blanching had no impact on tissue firmness during refrigerated storage for 1 year (p>0.098). There were no differences in flavor-active lipid oxidation products (E,Z)-2,6-nonadienal and (E)-2-nonenal, and consumers (n=110) were unable to differentiate between control and 90 s blanched cucumber pickles stored for 62 days. Exocarp color and mesocarp opacity were preserved by the blanching treatment, potentially extending product shelf life. This method offers processors an option for reducing the risk of microbial contamination while maintaining the quality attributes associated with refrigerated cucumber pickles. PRACTICAL APPLICATION: Refrigerated pickles do not undergo thermal processing, which can leave them vulnerable to microbial contamination. This study illustrates that adding a brief blanching step in refrigerated pickle processing can reduce indigenous microbiota without negatively impacting quality attributes. This blanching process could assist pickled vegetable manufacturers in providing additional safeguards for consumers while maintaining a high-quality product.

Developmental morphoanatomy of the fruit of Isertia hypoleuca Benth. (Rubiaceae)

Isertia Schreb. is a Rubiaceae associated with secondary tropical forests, represented by fifteen species distributed in Central and South America. The fruit of Isertia hypoleuca Benth. displays morphological peculiarities which, along with imprecise use of fruit terminology and typology, hamper its classification. We studied I. hypoleuca Benth. pericarp and seed morphologically and anatomically with the objectives of establishing the ontogenetic stages of fruit development and correcty interpret fruit typology. Four stages were recorded; main features are differences in exocarp color, biomass increment, and endocarp and exotesta sclerification process. Based on ontogeny, we classifiy the fruit of I. hypoleuca as a drupe.

Analisis Tingkat Keragaman Cempedak di Kabupaten Bangka dan Kabupaten Bangka Barat berdasarkan Karakter Morfologi

Indonesia is one of central plant genetic diversity in the world, especially for tropical fruits such as Durian, Mangosteen, and Cempedak. Bangka island is one area of the spread of Cempedak in Sumatera. Each plant has a different gene diversity in each tree. Information on the genetic diversity of plant can be known through morphological approaches. Research analyzing the level of diversity based morphological character has never been conducted in Bangka and West Bangka Region. The purpose of this research are to test the level of Cempedak in Bangka Island based on morphology character, so that can bring basic information about the diversity of Cempedak. The location of exploration of this research are in Bangka and West Bangka Region. Determination of sample trees using purposive sampling method. Morphological character parameters are observed in vegetative andgenerative organs which include qualitative and quantative character. Data processing is carried out with reference to UPGMA through the NTSYpc 2.1 program. The result of this research have been founded 6 cultivars of Cempedak, they are Cempedak Kuning, Cempedak Tembaga, Cempedak Nangka, Cempedak Tikus, Cempedak Ular and Cempedak Kapas, they have variative characteristic of leaves, tree, fruit, and seed. The result of similarities analysis of 6 cultivars of Cempedak are 2 main category with 38 % similarities coefficient and 62% differences coefficient. The most diverse morphological character is the shape and size of the leaves, the shape and size of the fruit, the fruit exocarp color, the shape of exocarp surface and the shape of the seeds.

INFLUENCE OF LOW VIGOUR ROOTSTOCKS ON GROWTH AND FRUITING PROCESS OF ‘REGINA’ CULTIVAR

The aim of this paper was to study the influence of low vigor rootstocks on the 'Regina' cherry cultivar. The study was conducted at Research Institute for Fruit Growing Pitesti, Arges county, Romania between 2019 and 2021. A bifactorial experiment was set up, with A factor-the rootstock ('Gisela 3', 'Gisela 5', 'Gisela 12' and 'Weigi 2') and B factor-the study year (2019, 2020 and 2021). Fruiting and vegetative growth data (fruit production, the trunck cross-section area-TCSA, the annual increase of TCSA, the productivity index and the ratio between the fruit production and the annual increase of TCSA), as well as fruit quality data (fruit mass, firmness, pH, total soluble content, chromatic coordinates of epicarp color and chlorophyll fluorescence) were collected. 'Gisela 5' rootstock recorded the highest value of TCSA annual increase (11.46 kg/cm2) and had also the highest cromatic coordinates values: colour brightness (25.68), red pigment (15.61) and yellow content (4.12).The highest vigor of the cultivar 'Regina' was observed in 'Weigi 2' rootstock variant (with an TCSA value of 44.71 cm2), given that 'Weigi 2' TCSA annual increase was similar to 'Gisela 5'. 'Gisela 3' rootstock stood out for its fruit highest pH (3.97), fruit yield (13.51 t/ha), lowest vigor (TCSA=24.19 cm2), smallest annual TCSA increase (6.11 cm2), highest productivity index 0.219 kg/cm2) and highest fruit production to annual TCSA increase ratio (1.79 kg/cm2). Taking into account climatic accidents that marked the spring of 2021, on the average of the study years, the cultivar 'Regina' grafted on the rootstock 'Gisela 12' was distinguished by fruit weight (10.02 g), firmness (66.53 units HPE Bareiss) and TSS (16.03°Brix) on the background of the lowest fruit yield. A negative very signifficant correlation between fruit yield and fruit quality traits (weight, firmness and total soluble solids) was found.

Sorbitol immersion controls chilling injury in CA stored ‘Palmer’ mangoes

Chilling injury (CI) in mangoes can be reduced using a controlled atmosphere (CA) and sorbitol immersion, although studies combining these treatments have yet to be recorded. Therefore, the objective of this study was to use multivariate analysis to evaluate the effectiveness of these methods in controlling CI. ‘Palmer’ mangoes were immersed in 0.1 and 2.5 % (w/v) sorbitol solutions and stored under CA (5 % O2 + 5 % CO2) at 8 °C for 30 d. The evaluations were performed under CA storage conditions (0, 10, 20, and 30 d), after which the fruit were transferred to an ambient temperature environment (∼23 °C) for a further 7 days. CI was minimized in mangoes treated with 2.5 % sorbitol and stored in a CA. In addition, the physicochemical variables (soluble solids content, titratable acidity, SSC/TA ratio, and pH), firmness, and mesocarp color (L*, hº, and C*) were not affected. CI development was associated with increased fresh weight loss and epicarp color (L*, hº, and C*). Hydrogen peroxide (H2O2) levels were related to CI symptom development, which intensified with the transfer to an ambient temperature, mainly due to increased electrolyte leakage (EL), lipid peroxidation (LP), and polyphenol oxidase (PPO) activity. CI inhibition in mangoes treated with 2.5 % sorbitol under a CA was related to the non-enzymatic (vitamin C and total polyphenols) and enzymatic (superoxide dismutase – SOD, catalase – CAT, and ascorbate peroxidase – APX) defense metabolisms, allowing for the quality of the fruit to be maintained for up to 30 d at 8 °C.

Biostimulant Application Improves Yield Parameters and Accentuates Fruit Color of Annurca Apples

The Annurca apple is a typical fruit from Southern Italy that is notable for its high firmness and characteristic flavor, and presents positive effects on human health. The aim of the present study was to improve the agronomic characteristics of Annurca trees and the quality of their fruits by the use of plant biostimulants. We performed the study with three biostimulants (protein hydrolysates, seaweed extracts, and microalgae) to determine their effects on trees and fruits at harvest and during fridge conservation. The measurements in the field concerned the production per plant, the number of fruits, the diameter and fruit weight, the diameter of trunk, the weight of pruning, the first harvest %, and yield efficiency (plant prod./TCSA) for both growing seasons 2018–2019. The analyzed fruit parameters at harvest and during the fridge conservation were: flesh firmness, epicarp color, total soluble solids, pH, and titratable acidity. The results showed positive effects of the biostimulants on the production and the color parameters, especially with microalgae enhancing fruit redness (5-fold) and color index (8.5-fold). In particular, protein hydrolysates and microalgae increased the production (10.4%), diameter of the fruits (7.0%), the first harvest percentage (37.8%), and yield efficiency (6.9%). The tested plant biostimulants showed no significant effect on the measured qualitative parameters. This study represents the first detailed research on the use of different types of biostimulants on Annurca trees and their impact on the quality of its fruits from harvest to storage, and may present a sustainable alternative for the “melaio” processes.

Influence of maturity stage on physical and chemical characteristics of fruit and physiological quality of seeds of Physalis angulata L.

Physalis angulata L. is an annual herb of the Solanaceae family, known in Brazil as camapu. Its fruits are widely eaten due to their high nutritional content and various plant parts are also used for medicinal purposes plant. The objective of this study was to evaluate the physiological maturity of P. angulata seeds during fruit development and maturation, as well as to identify the tolerance method for seed desiccation, contributing to the conservation of this species. Fruits and seeds were harvested at 15, 22, 29, 36 and 43 days after anthesis (DAA). The fruits were characterized regarding length, diameter, weight, total soluble solids, epicarp color, total number of seeds, and fresh seed weight. For determination of the seed physiological quality at different maturation times, freshly harvested seeds were dried at room conditions for 72 h and evaluated for water content, dry weight, germination percentage, germination index and seedling emergence. The desiccation tolerance was analyzed through fast and slow methods utilizing silica gel and saline solution of CaCl2. Significant increases were found in all physical and chemical traits of the fruits during development. Epicarp, nervure and calyx color can be used as good indicators of the degree of maturity, allowing identifying the best fruit harvest time. The seed physiological maturity of P. angulata was reached at 36 days after anthesis. The drying speed did not influence the seed germination percentage, germination index and vigor. P. angulata has orthodox seed storage behavior and can tolerate water content below 7%, which contributes to the maintenance of high viability (above 90%) for prolonged periods. Our findings can guide the conservation of P. angulata in seed banks and their use in breeding programs to obtain new hybrids.

Momento de colheita de sementes de <i>Albizia hasslerii</i> (Chod.) Burkart em função da cor do fruto

O objetivo deste estudo foi identificar a cor do fruto de Albizia hasslerii que corresponde a sementes com maior potencial fisiológico. Os frutos foram colhidos em diferentes estádios de maturação para a realização das análises, sendo classificados visualmente em quatro cores: 100% verde (estádio 1), ≤ 50% marrom (estádio 2), entre 50% e 99,9% marrom (estádio 3) e 100% marrom (estádio 4). Posteriormente, procedeu-se a mensuração dos atributos biométricos das sementes, e simultaneamente, Risssos testes de germinação e vigor foram instalados. Para verificar a relação da maturação de frutos com a biometria e o potencial fisiológico de sementes, determinou-se o coeficiente de correlação de Spearman (ρ). O delineamento utilizado foi inteiramente casualizado, sendo os resultados submetidos à análise de variância, e as médias comparadas pelo teste de Tukey, a 5% de probabilidade. As sementes provenientes dos frutos que se encontravam nos estádios 3 e 4, manifestaram maior germinação e emergência, menores médias de teor de água e maior matéria seca, sendo esses indicadores do melhor momento de colheita de frutos. Já as sementes obtidas de frutos verdes apresentaram baixa germinação e vigor, alto teor de água e menor matéria seca. Conclui-se que as sementes com alto potencial fisiológico estão em frutos com cor 100% marrom, porém a partir de 50% de cor marrom já podem ser colhidos. Portanto, a cor dos frutos é considerada um indicador de maturidade fisiológica para a espécie Albizia hasslerii.

Spatial Distribution and Morphology Character of Podang Mangoes (Mangifera indica L.) from Five Sub-district in Kediri Regency, East Java, Indonesia

This study obejctives to determine the distribution maps and identify the morphological character of local Mangga Podang at five sub-districts in Kediri. This research used purposive sampling method for collecting data. Coordinate of local mango wasanalyzed using QGIS software version 3.6. Morphological characters are examined by observing the morphology. Microclimate factors that were measured are altitude, intensity, temperature and moisture of soil and air, soil pH, and soil nutrient. Morphological characterswere analyzed for homogenity by statistical test. The results showed that Mangga Podang distribution has spread in residential areas and has different altitude factors between 85-459 meters above sea level. The total population(individu/400m2) found in this study were Mojo10(11.2%), Banyakan 17 (19.1%), Grogol8 (9%), Semen 3 (3,4%)and Tarokan51 (57.3%). Mangga Podangof Kediri Regency generally have homogenous morphological characters, but there were the special character which differs each other, they are the number of flowers in 1 panicle, the weight of ripe fruit and exocarp color of ripe fruits. This morphological variation dependent to light intensity, altitudinal, the velocity of wind and soil nutrient factors.

Physicochemical quality of araçaúna and grumixama at different ripening stages

Abstract The physicochemical characteristics of fruits of species native to the Atlantic Forest are little known, especially during ripening. The aim of this work was to evaluate the effect of the interaction between ripening period and post-harvest storage of araçaúna and grumixama. Fruits were harvested at three ripening stages: green, partially ripe and ripe, according to the epicarp color, and separated into two groups, being stored for 2 and 48 hours. The following variables were evaluated: longitudinal (LD) and cross-sectional (CD) diameter, LD / CD ratio, fresh fruit mass (FM), pulp yield (PY), pH, soluble solids content (SS), titratable acidity (TA), SS / TA ratio, and ascorbic acid content (AA). Araçaúna fruits stand out due to their high PY (74.43%), with low SS (2.07 ºBrix) and high TA (1.17% citric acid). However, harvesting fully ripe fruits increases SS by 21% and reduces TA by 32.5%. Grumixama fruits are slightly sweet (6.06 ºBrix), with low acidity (0.39% citric acid), high vitamin C content (206.94 mg of ascorbic acid/100g of pulp), and harvest must be performed when fruits are fully ripe. Both species have pulp of potential quality to be commercially exploited, especially for processing.

Rapid Characterization of the Genetic Loci Controlling Commodity Traits of Chinese Hami Melon (Cucumis melo var. Saccharinensis Naud.) through Multiplexed Shotgun Genotyping

The genetic architecture and the genetic loci controlling commodity traits in this Hami melon have not been characterized. Multiplexed shotgun genotyping (MSG) was used to genotype an F2 population of 370 Chinese Hami melon progeny. A total of 47,609 single nucleotide polymorphism (SNP) markers were obtained after strict filtering. Thebins were used to construct a genetic linkage map with a total length of 1572.954 cM. Quantitative trait locus (QTL) analysis revealed that fruit color was controlled by one major gene about 2 Mb region on chr09, while exocarp color (EC) was controlled by one major gene about 1.9 Mb on chr04, and skin spotting was controlled by two dominant genes, one in the same region of chr04as the EC QTL and the other in the 1031.05 kb region on chr02. Two major QTLs on chr03 and chr05 were related pleiotropically to several quantitative fruit traits, namely, edge sugar content (ES), center sugar content (CS), fruit weight (FW), and fruit length (FL). A further QTL on chr09 also influenced ES, while five other QTLs affected FL. This study was the first to conduct genetic architecture analysis and QTL mapping in Chinese Hami melon with high-density markers and a large target population.

Effect of blue light on red color development and anthocyanin accumulation of sweet cherries

The red color of sweet cherries (Prunus avium L.) is important for their marketability. Anthocyanin synthesis in ‘Satohnishiki’ is highly dependent on light conditions, and ultraviolet (UV) light from 280 to 320 nm (UV-B) reportedly has a strong effect on anthocyanin synthesis in the cultivar ‘Satohnishiki’. The effect of visible light, such as blue light, on anthocyanin accumulation in sweet cherries has not yet been studied. This research examined the effect of blue light on exocarp color development and anthocyanin accumulation in ‘Satohnishiki’ and ‘Napoleon’ yellow flesh, blush sweet cherry cultivars. Using a light emitting diode, the effect of blue light on anthocyanin accumulation was compared with that of UV-B. The blue light of 450 nm induced anthocyanin accumulation and red color development in both cultivars, while its effect was lower than that of UV-B light. The efficiency of the blue light wavelength on anthocyanin accumulation in ‘Satohnishiki’ was examined with using 430 to 490 nm blue lights, and 450 nm was more effective than other blue lights. Blue light may play an important role in red color development in the fruits of both cultivars under a tree canopy.

Seed physiological quality and harvest point of dovyalis fruits

ABSTRACT The main propagation mode of dovyalis is by seeds, what makes important to determine the ideal moment of fruit harvest. This study aimed to evaluate the physiological seed quality and harvest time of dovyalis fruits. To determine the fruit physical attributes, they were visually classified into five classes, according to the maturity stages, based on the external color of the exocarp: stage 1: green fruit; stage 2: yellowish-green; stage 3: yellowish-brown; stage 4: brown; stage 5: intense brown. The seed extraction to evaluate the physiological quality was based on the seed water content, germination percentage, germination speed index and determination of the dry biomass of the shoot, root and seedlings originated from these seeds. The experimental design was completely randomized, containing 25 seeds per treatment and 4 replicates. The fruit color during ripening varies from green to intense brown. The fruits reach their largest size and fresh biomass accumulation in the stage 4, with the brown exocarp color represented in the Munsell chart by 2.5YR 3/4. The removal of seeds for propagation should occur from the stage 2 (2.5GY 5/8), when the fruits have a yellowish-green color, although no statistical variation is observed in the number of seeds during maturation.

Ultrasound-vacuum infusion effect on jalapeño pepper (Capsicum annuum L.) blanching and thermal behavior of its pectin methylesterase

Blanching treatment is an indispensable operation on fruit and vegetable processing, nevertheless, it is also capable to produce significant changes in sensory properties of such products, mainly texture and color. Pectin methylesterase (PME) treatments are an important process for texture improvement. These treatments can be applied either by means of endogenous PME activation or by infusion of exogenous PME in combination with or without a calcium salt; along with the use of temperatures around 60 °C, in order to attain the maximum activity of PME. In the present study, jalapeño pepper PME showed its highest activity at 55 °C. Likewise, it displayed a great thermal stability below 50 °C, as well as a long-time retention of its initial activity at such temperature. In the same way, when a solution of 15 U·mL−1 of PME with 10 mM CaCl2 was applied through ultrasound-assisted vacuum-infusion for 5 min, blanching-induced changes in texture and exocarp color of jalapeño pepper were reduced. Simultaneously, an increase of fruit tissue PME activity was observed with specific treatment conditions.