Stages Of Fruit Ripening Research Articles

Development Changes in the Physicochemical Composition and Mineral Profile of Red-Fleshed Dragon Fruit Grown under Semi-Arid Conditions

Red-fleshed dragon fruit offers an array of bioactive compounds. Its cultivation is gaining momentum in India, including in arid and semi-arid conditions. Among various factors, the fruit developmental stages and climatic conditions of locations greatly influence the biosynthesis and actual contents of different bioactive compounds and mineral contents of the fruit. The changes in physical attributes, and bioactive and mineral content in red-fleshed dragon fruit grown in semi-arid conditions in India were assessed and quantified at six developmental stages. Significant changes occurred in the physical attributes of the fruit and the bioactive compounds and mineral content during the fruit maturation stages of the red-fleshed dragon fruit. The fruit physical characteristics, such as fruit size, fruit and pulp weight gain, peel thickness, and fruit firmness, along with eating quality parameters, such as soluble solids, sugars, acidity and soluble proteins, were observed at optimum at 35 days after anthesis (DAA). The decrease in total phenolics (29.96%), total flavonoids (41.06%), and vitamin C (75.3%) occurred throughout the fruit development stages, whereas the content of betalains, which was detected initially at 25 DAA, increased (48.6%) with the progression of the fruit development stages. However, the antioxidant capacity and free radical scavenging activity demonstrated variable trends throughout the fruit maturation period. There was an increasing trend in all the minerals up to 35 days, followed by a slight decrease, except for phosphorus content, which increased until the last stage of evaluation. The colour characteristics, in conjunction with the bioactive and antioxidant potential determined in the present study, suggest that red-fleshed dragon fruit can be harvested at 35 DAA for long-distance transportation, and from 35 to 40 DAA for local marketing.

Antioxidant Properties of Pulp, Peel and Seeds of Phlegrean Mandarin (Citrus reticulata Blanco) at Different Stages of Fruit Ripening.

In this work, we assess the potential of waste products of Phlegrean mandarin (Citrus reticulata Blanco), namely seeds and peel, to be reutilized as a source of bioactive compounds beneficial for the human diet. Starting from the evidence that the by-products of this specific cultivar are the most powerful sources of antioxidants compared to pulp, we have investigated if and how the bioactive compounds in peel and seeds may be affected by fruit ripening. Three stages of fruit ripening have been considered in our study: unripe fruits = UF, semi-ripe fruits = SRF, ripe fruits = RF. The overall results indicated that RF showed the highest concentration of antioxidants. Among fruit components, peel was the richest in total antioxidant capacity, total polyphenol content, total flavonoids, total chlorophylls and carotenoids, while seeds exhibited the highest concentration of total condensed tannins and ascorbic acid. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay indicates the occurrence, in peel extracts, of 28 phenolic compounds, mainly flavonoids (FLs); in seeds, 34 derivatives were present in the first stage (UF), which diminish to 24 during the ripening process. Our data indicated that the content of phytochemicals in citrus strongly varies among the fruit components and depends on the ripening stage. The higher antioxidant activity of peel and seeds, especially in RF, encourage a potential use of by-products of this specific citrus cultivar for industrial or pharmacological applications. However, to maximize the occurrence of desired bioactive compounds, it is important also to consider the ripening stage at which fruits must be collected.

Assessment of weather effect on flower morphogenesis and fruit set in mango varieties in central India

A two-year field experiment was initiated in 2017-18 and 2018-19 years simultaneously to assess temperature on flower morphogenesis stages, flower sex ratio (hermaphrodite/staminate male flower) and fruit set in monoembryonic Langra and Amrapali varieties. Different dates of flower phenological stages viz., bud, panicle, bloom and flower initiation, pea, marble, egg, and maturity of fruits were recorded. The Langra variety exhibited bud initiation after mid December whereas Amrapali variety by the end of December. The range of mean maximum / minimum temperature as 26-31/10-12 °C promoted hermaphrodite flowers per panicle by 74 per cent in Langra variety, whereas range of 27-29/11-13 °C favored by 35 per cent in Amrapali variety. A positive and significant correlation between total number of flower / panicle and flower sex ratio in both the varieties suggested that higher temperature during initial flower phenologies improved number of hermaphrodite flowers. A mean minimum temperature for producing more number of hermaphrodite flower exhibited a range of 11-14 °C under central Indian conditions. Fruit set was maximum during pea stage and decline afterwards in marble and fruit maturity stages due to sudden rise in temperature at marble stage that caused in drop down of humidity thereby resulted in fruit drop in both the varieties.

Production and post-harvest quality of mini-watermelon crop under irrigation management strategies and potassium fertilization

ABSTRACT The occurrence of water sources with a high concentration of salts stands out as a limiting factor for production in Northeast Brazil. Thus, the search for strategies that minimize the effect of salt stress on crops is of fundamental importance. In this context, this study was conducted with the objective of evaluating the production and post-harvest quality of Sugar Baby mini-watermelon fruits under different irrigation management strategies with saline water and potassium fertilization. The experiment was conducted in a greenhouse, using a randomized block design, in an 8 × 3 factorial scheme, with three replicates, corresponding to eight saline water irrigation management strategies (No stress throughout the crop cycle; irrigation with saline water in the vegetative, vegetative/flowering, flowering, flowering/fruiting, fruiting, fruiting/maturation and fruit maturation stages) and three doses of potassium (50, 100 and 150% of the recommended dose). The dose of 100% corresponded to 150 mg K2O kg-1 of soil. Water with low and with high electrical conductivity (0.8 and 4.0 dS m-1, respectively) was used. Irrigation with water of 4.0 dS m-1 in the flowering and fruit maturation stages is a promising strategy for the cultivation of mini-watermelon, as it does not compromise production. Fertilization with 50% of K2O recommendation can be used in the cultivation of mini-watermelon without losses in yield. Mini-watermelon plants fertilized with 150% of K2O recommendation and irrigated with water of high salt concentration continuously in the vegetative/flowering and fruiting stages reduced the contents of soluble solids and ascorbic acid in the fruits.

GCS-YOLOV4-Tiny: A lightweight group convolution network for multi-stage fruit detection.

Fruits require different planting techniques at different growth stages. Traditionally, the maturity stage of fruit is judged visually, which is time-consuming and labor-intensive. Fruits differ in size and color, and sometimes leaves or branches occult some of fruits, limiting automatic detection of growth stages in a real environment. Based on YOLOV4-Tiny, this study proposes a GCS-YOLOV4-Tiny model by (1) adding squeeze and excitation (SE) and the spatial pyramid pooling (SPP) modules to improve the accuracy of the model and (2) using the group convolution to reduce the size of the model and finally achieve faster detection speed. The proposed GCS-YOLOV4-Tiny model was executed on three public fruit datasets. Results have shown that GCS-YOLOV4-Tiny has favorable performance on mAP, Recall, F1-Score and Average IoU on Mango YOLO and Rpi-Tomato datasets. In addition, with the smallest model size of 20.70 MB, the mAP, Recall, F1-score, Precision and Average IoU of GCS-YOLOV4-Tiny achieve 93.42 ± 0.44, 91.00 ± 1.87, 90.80 ± 2.59, 90.80 ± 2.77 and 76.94 ± 1.35%, respectively, on F. margarita dataset. The detection results outperform the state-of-the-art YOLOV4-Tiny model with a 17.45% increase in mAP and a 13.80% increase in F1-score. The proposed model provides an effective and efficient performance to detect different growth stages of fruits and can be extended for different fruits and crops for object or disease detections.

Biometria do fruto e qualidade fisiológica da palmeira Veitchia merrilli (Becc) H. E. Moore de acordo com o estágio de maturação do fruto

ABSTRACT Veitchia merrilli (Becc) H. E. Moore is a palm tree widely used in gardening. Due to the continuous production of flowers on the inflorescences, there are fruits and seeds in various stages of maturation on the same plant, making it hard to determine the best fruit maturation stage for obtaining vigorous seeds. This study measured the biometric characteristics of the fruit at different stages of maturation and identified the best fruit maturation stage from which to obtain seeds with optimal physiological quality. Mature fruits were harvested from the tops of 10 trees and the ground, categorized according to their maturation stage and measured for overall length, equatorial diameter, and fresh weight. An experiment to identify the best fruit maturation stage for obtaining seeds of the V. merrilli with satisfactory physiological quality was carried out in a greenhouse, with five treatments (maturation stage) and ten replications; each plot was composed of 20 seeds. Plant height, root length, stem diameter, root and above ground dry weight, total dry weight, and Dickson’s quality index were measured. The green fruit stage is the most suitable for obtaining seeds of V. merrilli with the best physiological qualities. The fruits at the dark red maturity stage had the greatest length, while the those in the green transition stage had the greatest diameter and fresh weight.

A multi-channel convolutional neural network driven computer vision system towards identification of species and maturity stage of banana fruits: case studies with Martaman and Singapuri banana

Banana is a widely consumed fruit worldwide due to its high nutritional values. The nutritional impact of banana considerably varies with the species and ripening stages. The existing practices of both species and ripening stage detection of banana are performed majorly by human experience and chemical analysis. This paper presents a computer vision-based system development to identify banana species and corresponding ripening stages simultaneously. The proposed system is less expensive, non-invasive and faster with potential to provide up to 98% accuracy. The work utilises multi-channel convolutional neural network (CNN) architecture to classify the species and ripening stage in a single go. The results of the proposed system was assessed against different popular metrics and found competitive to the existing techniques. This technique can be also integrated to a handheld device or mobile app in future for firsthand assessment by the consumers and sellers in the market.

A multi-channel convolutional neural network driven computer vision system towards identification of species and maturity stage of banana fruits: case studies with Martaman and Singapuri banana

A multi-channel convolutional neural network driven computer vision system towards identification of species and maturity stage of banana fruits: case studies with Martaman and Singapuri banana

Volatile compounds of umbu (Spondias tuberosa Arruda) fruits during post-harvest ripening from two accessions

The chemical composition of volatile compounds from Spondias tuberosa fruits were investigated at four days of maturity and from two accessions. These days were characterized through the compounds’ profiles obtained by extracting volatiles using solid-phase microextraction in headspace mode (HS-SPME) and analyzed by gas-chromatography coupled to mass spectrometry (GC-MS). A total of 27 and 22 compounds were identified from the EPAMIG-C02 and EPAMIG-C10 accessions, respectively. The main chemical class in both accessions were the esters, aldehyde, alcohols and terpenes. The study revealed a tendency to increase the ester content and decrease the aldehyde and terpene content during four days of post-harvest ripening for the two accessions. This behavior may be monitored by five key compounds such as two esters (ethyl butanoate and ethyl hexanoate) and three aldehydes (hex-2-enal, nonanal and dec-2-enal). These compounds may be used as markers for the maturity stage for the two accessions. The Principal Components Analysis (PCA) accumulated 73.85% of the total variance in principal components 1 and 2 and showed that it is possible to differentiate the fruit ripening stages through these compounds.

Variation of Squalene Content of Oils Obtained from Olives Harvested at Different Times from Gemlik and Kilis Yaglık Cultivars in Kilis Region

Olive (Olea europaea L.) is a significant crop especially in Mediterranean countries. In Turkey olives and olive oil have a major agricultural importance Olives and olive oil have been used not only nutrient and as a flavor enhancer in Mediterranean dishes, but also a medicine because of having essential roles for human health. the pharmaceutical value and uses are related to biochemical content and compounds. Mainly four chemical sources: mono-unsatured fatty acids, polyphenols, carotenoids and squalene are functional bioactives in olive oil particularly for pharmaceutical affects. The present study was designed to examine changes of squalene contents of olive oil gained Kilis Yağlık and Gemlik olive cultivars’ fruits harvested in tree different time along the two years. Squalene content in olive oils varied according to harvest time, cultivar and cultivation year. Accordingly, the variety affected the squalen content, in Gemlik cultivar squalene was more than Kilis Yaglık cultivar. In terms of its cultivated year, in the high yield year, an increase in squalen content was observed. In olive oil, squalen content decreased first then increased by the fruit maturation.Therefore, harvest time effected biochemical content of oil by the fruit ripening stages.

The Intragenesis and Synthetic Biology Approach towards Accelerating Genetic Gains on Strawberry: Development of New Tools to Improve Fruit Quality and Resistance to Pathogens.

Under climate change, the spread of pests and pathogens into new environments has a dramatic effect on crop protection control. Strawberry (Fragaria spp.) is one the most profitable crops of the Rosaceae family worldwide, but more than 50 different genera of pathogens affect this species. Therefore, accelerating the improvement of fruit quality and pathogen resistance in strawberry represents an important objective for breeding and reducing the usage of pesticides. New genome sequencing data and bioinformatics tools has provided important resources to expand the use of synthetic biology-assisted intragenesis strategies as a powerful tool to accelerate genetic gains in strawberry. In this paper, we took advantage of these innovative approaches to create four RNAi intragenic silencing cassettes by combining specific strawberry new promoters and pathogen defense-related candidate DNA sequences to increase strawberry fruit quality and resistance by silencing their corresponding endogenous genes, mainly during fruit ripening stages, thus avoiding any unwanted effect on plant growth and development. Using a fruit transient assay, GUS expression was detected by the two synthetic FvAAT2 and FvDOF2 promoters, both by histochemical assay and qPCR analysis of GUS transcript levels, thus ensuring the ability of the same to drive the expression of the silencing cassettes in this strawberry tissue. The approaches described here represent valuable new tools for the rapid development of improved strawberry lines.

Chemical composition of forage watermelon fruit at different maturity stage or storage length

This study aimed to assess the chemical responses of forage watermelon fruit at different maturity stages or storage lengths, performing two experimental tests. In the first test, four maturity stages were assessed: 30, 45, 60, and 75 days after anthesis, with four replicates. In the second test, fruits were maintained under three storage lengths: T1D (harvest day), T3M (3 months after harvest), and T6M (6 months after harvest), with eight replicates. Experimental design was completely randomized in both experimental tests. Fruit maturity stage did not affect crude protein, total carbohydrate, neutral detergent fiber, in vitro dry matter digestibility (IVDMD), pulp firmness, soluble solids content and total pectin content, but increased acid detergent fiber content from 45 days after anthesis. Storage length up to six months after harvest increased ash, crude protein and IVDMD, and reduced the content of soluble solids. Forage watermelon fruit can be harvested from 30 to 75 days after anthesis equivalent to 75 - 120 days after planting, and they can be stored under tree shade up to 6 months after harvest.

Comparative Proteomic Analysis within the Developmental Stages of the Mushroom White Hypsizygus marmoreus.

(1) Background: The white Hypsizygus marmoreus is a popular edible mushroom in East Asia markets. Research on the systematic investigation of the protein expression changes in the cultivation process of this mushroom are few. (2) Methods: Label-free LC-MS/MS quantitative proteomics analysis technique was adopted to obtain the protein expression profiles of six groups of samples collected in different growth stages. A total of 3468 proteins were identified. The UpSetR plot analysis, Pearson correlation coefficient (PCC) analysis, and principal component (PC) analysis were performed to reveal the correlation among the six groups of samples. The differentially expressed proteins (DEPs) were organised by One-way ANOVA test and divided into four clusters. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed to divide the DEPs into different metabolic processes and pathways in each cluster. (3) Results: The DEPs in cluster 1 are of the highest abundance in the mycelium and are mainly involved in protein biosynthesis, biosynthesis of cofactors, lipid metabolism, spliceosome, cell cycle regulation, and MAPK signaling pathway. The DEPs in cluster 2 are enriched in the stem and are mainly associated with protein biosynthesis, biosynthesis of cofactors, carbon, and energy metabolism. The DEPs in cluster 3 are highly expressed in the primordia and unmatured fruiting bodies and are related to amino acids metabolism, carbon and carbohydrate metabolism, protein biosynthesis and processing, biosynthesis of cofactors, cell cycle regulation, MAPK signaling pathway, ubiquitin-mediated proteolysis, and proteasome. The DEPs in cluster 4 are of the highest abundance in the cap and are mainly associated with spliceosome, endocytosis, nucleocytoplasmic transport, protein processing, oxidative phosphorylation, biosynthesis of cofactors, amino acids metabolism, and lipid metabolism. (4) Conclusions: This research reports the proteome analysis of different developmental stages during the cultivation of the commercially relevant edible fungi the white H. marmoreus. In the mycelium stage, most of the DEPs are associated with cell proliferation, signal response, and mycelium growth. In the primordia and unmatured fruiting bodies stage, the DEPs are mainly involved in biomass increase, cell proliferation, signal response, and differentiation. In the mature fruiting body stage, the DEPs in the stem are largely associated with cell elongation and increase in biomass, and most of the DEPs in the cap are mainly related to pileus expansion. Several carbohydrate-active enzymes, transcription factors, heat shock proteins, and some DEPs involved in MAPK and cAMP signaling pathways were determined. These proteins might play vital roles in metabolic processes and activities. This research can add value to the understanding of mechanisms concerning mushroom development during commercial production.

Physiological Quality of Swingle Citrumelo Seed after Refrigerated Storage of Fruits and Seeds

For citrus, there is no definition of the ideal fruit harvesting point for seed extraction. Some studies have shown the positive effect of postharvest refrigerated storage of fruits to obtain quality seeds. This study aimed to evaluate the influence of the fruit maturation stage on the germination of Swingle citrumelo (CS) seeds after the refrigerated storage of fruits and seeds. CS fruits were harvested at 180 days after anthesis (DAA); 210 DAA and 240 DAA. Fruits and seeds were stored in cold chamber for 0, 15, 30, and 45 days. Physicochemical analyses were performed on fruits (colour, soluble solids, acidity and ratio) and seeds (water content, germination, and emergence). Germination of seeds extracted from fruits harvested at 180, 210, and 240 DAA, without refrigerated storage, showed a positive correlation with colour index. The refrigerated storage of fruits and seeds extracted from fruits harvested at 210 DAA, increased the seed germination rate. Peel colour (IC) was correlated positively with the germination of Swingle citrumelo seeds. The results of this study revealed that the absence of refrigerated storage, harvesting Swingle citrumelo fruits, with ripe characteristics (end of harvest), results in a high seed germination rate. On the other hand, refrigerated storage of fruits and seeds extracted from fruits harvested at mid-harvest increases the seed germination rate.

Genome-wide identification and expression profiling of durian CYPome related to fruit ripening.

Durian (Durio zibethinus L.) is a major economic crop native to Southeast Asian countries, including Thailand. Accordingly, understanding durian fruit ripening is an important factor in its market worldwide, owing to the fact that it is a climacteric fruit with a strikingly limited shelf life. However, knowledge regarding the molecular regulation of durian fruit ripening is still limited. Herein, we focused on cytochrome P450, a large enzyme family that regulates many biosynthetic pathways of plant metabolites and phytohormones. Deep mining of the durian genome and transcriptome libraries led to the identification of all P450s that are potentially involved in durian fruit ripening. Gene expression validation by RT-qPCR showed a high correlation with the transcriptome libraries at five fruit ripening stages. In addition to aril-specific and ripening-associated expression patterns, putative P450s that are potentially involved in phytohormone metabolism were selected for further study. Accordingly, the expression of CYP72, CYP83, CYP88, CYP94, CYP707, and CYP714 was significantly modulated by external treatment with ripening regulators, suggesting possible crosstalk between phytohormones during the regulation of fruit ripening. Interestingly, the expression levels of CYP88, CYP94, and CYP707, which are possibly involved in gibberellin, jasmonic acid, and abscisic acid biosynthesis, respectively, were significantly different between fast- and slow-post-harvest ripening cultivars, strongly implying important roles of these hormones in fruit ripening. Taken together, these phytohormone-associated P450s are potentially considered additional molecular regulators controlling ripening processes, besides ethylene and auxin, and are economically important biological traits.

Optimizing irrigation and fertilization at various growth stages to improve mango yield, fruit quality and water-fertilizer use efficiency in xerothermic regions

Mango (Mangifera indica L.) is one of the widely grown fruit crops and brings remarkable economic benefit in the xerothermic regions of southwest China. However, mango yield and quality can not be guaranteed due to the severe seasonal drought, low precipitation and extensive management of water and fertilizer. To investigate the effects of irrigation amount and fertilizer regime on mango yield, fruit quality, water use efficiency (WUE) and partial fertilizer productivity (PFP), an orthogonal experiment [L9(3)4] was conducted on mango under drip fertigation during 2018–2019. The four factors were irrigation amount (IA) and fertilization rate at the flowering (FⅠ), fruit expansion (FⅡ) and fruit ripening (FⅢ) growth stages. There were three irrigation amounts, i.e., full irrigation (FI: 100%ETc), mild deficit irrigation (DIM: 75%ETc) and severe deficit irrigation (DIS: 50%ETc), and three fertilization rates, i.e., 75 (F75), 50 (F50) and 25 (F25) kg ha−1 using a compound water-soluble fertilizer (N:P2O5:K2O=20%:20%:20%). The results showed the order of factors influencing fruit yield and WUE in terms of their importance was IA, FⅡ, FⅠ and FⅢ, that influencing water, vitamin C and carotenoid contents in fruit was IA, FⅢ, FⅡ and FⅠ, and that influencing soluble solids and total sugar contents was IA, FⅢ, FⅠ and FⅡ. The WUE of DIMFⅠ50FⅡ75FⅢ25 was highest. FIFⅠ25FⅡ75FⅢ50 achieved the highest fruit yield, PFP and contents of soluble solid, vitamin C and carotenoid. DIMFⅠ25FⅡ50FⅢ75 had the highest total sugar content and the lowest titratable acid content. Based on the comprehensive scoring method, DIMFⅠ50FⅡ75FⅢ25 achieved the optimum score in terms of fruit yield and water–fertilizer use efficiency, while FIFⅠ25FⅡ75FⅢ50 was optimum for fruit quality. Further, the TOPSIS method indicated DIMFⅠ50FⅡ75FⅢ25 had the optimal comprehensive benefit. To obtain high yield, quality and water–fertilizer use efficiency, the recommended water and fertilizer scheduling was irrigation with 75% ETc and fertilization with 50, 75 and 25 kg ha−1 at the flowering, fruit expansion and fruit ripening stages, respectively. The research results provided a scientific reference for identified optimum combination irrigation and fertilizer in the xerothermic environment of southwest China.

Variation of lignan content and α-glucosidase inhibitory activity of Schisandra chinensis fruit at different maturation stages: Comparison with stem, leaf and seed

The fruit of Schisandra chinensis has been used for the treatment of various metabolic diseases for a long time. The bioactive constituents of the fruit are known as lignans with dibenzocyclooctadienes skeletons. In this study, changes in the content of four main lignans of S. chinensis, schizandrin (S1), schizandrin A (S2), gomisin N (S3) and wuweizisu C (S4), and anti-diabetic activities at the different maturation stages of fruits were investigated. In addition, comparison of stem, leaf and seed with fruit was conducted in order to determine the optimum harvest time of fruit with high functionality and seek an alternative to use the other parts of plant except the fruit. In the results, the total content of four lignans were kept relatively constant and the amount of S1 and S3 were more than that of S2 and S4. According to fruit maturity, the content of S1 and S2 increased, on the contrary, S3 and S4 decreased. α-Glucosidase inhibitory effect was higher in early matured fruits and decreased in medium and late matured fruits. Considering the correlation between lignan content and α-glucosidase inhibitory effect, the content of S4 appeared to be highly related to the inhibitory effect. All of examined lignans were also detected in other parts of the plant, especially showed higher level in stem and seed than in leaf. However, the content of each lignan was different in each part, that is, high content of S4 was detected in stem whereas the content of S3 was higher in seed. For the breeding of new cultivars of S. chinensis, it is necessary to cultivate early-maturing varieties with a high content of active ingredients as well as to find an alternative approach to use the various plant parts including stem, leaf and seed.

Machine Learning for Automatic Classification of Tomato Ripening Stages Using Electrophysiological Recordings

The physiological processes underlying fruit ripening can lead to different electrical signatures at each ripening stage, making it possible to classify tomato fruit through the analysis of electrical signals. Here, the electrical activity of tomato fruit (Solanum lycopersicum var. cerasiforme) during ripening was investigated as tissue voltage variations, and Machine Learning (ML) techniques were used for the classification of different ripening stages. Tomato fruit was harvested at the mature green stage and placed in a Faraday's cage under laboratory-controlled conditions. Two electrodes per fruit were inserted 1 cm apart from each other. The measures were carried out continuously until the entire fruits reached the light red stage. The time series were analyzed by the following techniques: Fast Fourier Transform (FFT), Wavelet Transform, Power Spectral Density (PSD), and Approximate Entropy. Descriptive analysis from FFT, PSD, and Wavelet Transform were used for PCA (Principal Component Analysis). Finally, ApEn, PCA1, PCA2, and PCA3 were obtained. These features were used in ML analyses for looking for classifiable patterns of the three different ripening stages: mature green, breaker, and light red. The results showed that it is possible to classify the ripening stages using the fruit's electrical activity. It was also observed, using precision, sensitivity, and F1-score techniques, that the breaker stage was the most classifiable among all stages. It was found a more accurate distinction between mature green × breaker than between breaker × light red. The ML techniques used seem to be a novel tool for classifying ripening stages. The features obtained from electrophysiological time series have the potential to be used for supervised training, being able to help in more accurate classification of fruit ripening stages.

Changes in phenolics and antioxidant capacities in fruit tissues of mandarin cultivars Kinnow and W. Murcott with relation to fruit development

Mandarin fruits are rich source of nutraceutical compounds and their concentration varies with respect to variety, fruit portion, and stage of fruit development. Therefore, this study investigated the effect of developmental stage on biochemical composition and antioxidant activities in fruit peel and pulp of Kinnow and W. Murcott mandarins. Results showed that total phenolic content (TPC) and total flavonoid content (TFC) in mandarin fruits ranged from 12.79 to 48.71 mg GAE g−1 and 2.08 to 7.57 mg RE g−1, respectively while the pectin concentration ranged from 6.00% to 19.26%. Fruit peel contained a higher amount of TPC, TFC, hesperidin, and pectin. With the progression of fruit development, the TPC, antioxidant activity, and hesperidin declined, whereas TFC and limonin content were the highest in August month. Both mandarins accumulated higher concentration of phenolics and antioxidants during August-September. Overall, the Kinnow is richer source of bioactive metabolites than W. Murcott. Practical applications The composition of citrus fruits vary with respect to genotype, maturity stage, and geographical location. This study presented the antioxidant potential of two mandarin cultivars viz; Kinnow and W. Murcott with respect to fruit maturity stage and fruit tissue. In both the mandarins the concentration of phenolic and antioxidant compounds were recorded to be higher at immature fruit stage as compared to the fully mature stage. Likewise, the fruit peel contained a greater concentration of these bioactive compounds than the fruit pulp.

Vibrations Analysis of the Fruit-Pedicel System of Coffea arabica var. Castillo Using Time–Frequency and Wavelets Techniques

Colombian coffee production is well-known, and selective manual harvesting plays a vital task in guaranteeing high ripe coffee fruit rates in this process, leading to its known worldwide aroma and flavor. To maintain this quality approach, selective harvesting methods based on mechanical vibrations are a promising alternative for developing technologies that could accomplish the challenging Colombian coffee production context. In this study, a vibrations analysis in coffee fruits at three ripening stages was carried out to evaluate the dynamic behavior at two frequency windows: 10 to 100 Hz and 100 to 1000 Hz. Two groups of fruits previously classified in the CIELab color space were chosen for the vibration test study samples. Time and frequency signals were characterized via FFT (fast Fourier transform), and bump wavelets were determined to obtain the frequency–time magnitude scalograms. The measurements were obtained in three degrees of freedom over the fruits: one for measuring the input force (computed in voltage way) and the other two measured by the velocity. The results revealed frequency ranges with specific resonant peaks between 24 and 45 Hz, and close to 700 Hz, where the ripe fruits presented higher magnitudes in the calculated parameters. FFT of the velocity and scaled mechanical impedance were used to estimate these frequency ranges. This work is an important step to identify a “vibrational fingerprint” of each Coffea arabica var. Castillo fruit-ripening stage. However, we consider that more experiments should be performed to reconstruct the modal shape in each resonance. In future studies, fatigue analysis could show which are the most effective frequency ranges to detach the ripe fruits from the perspective of a real selective coffee-harvesting scenario.