Fruit Quality Measurements Research Articles

Influence of Zinc Oxide Nanoparticles on the Productivity, Mineral Element Accumulation, and Fruit Quality of Tomato (Solanum lycopersicum L.)

Foliar application of zinc oxide nanoparticles (ZnO-NPs) is a promising strategy in modern agriculture. This method has shown significant potential in enhancing tomato yields, improving fruit quality, and increasing nutrient uptake. An experiment was conducted in cocopeat media under glasshouse conditions at Ladang 15, Universiti Putra Malaysia (UPM) in 2020 to evaluate the effectiveness of various doses of ZnO-NPs on plant growth, yield, nutrient uptake, and fruit quality in terms of profitability. A total of ten treatments were evaluated, consisting of five levels of ZnO-NPs (0 ppm, 25 ppm, 50 ppm, 75 ppm, and 100 ppm) and two tomato varieties (MARDI Tomato 1 and MARDI Tomato 3). The experiment utilized a split-plot design with four replications. The results indicated that the application of 100 ppm ZnO-NPs produced the maximum measures of plant growth and fruit quality, including the highest number of primary branches per plant (27.75), leaf area (27.80 cm²), photosynthetic rate (33.05 µmol/m²/s), stomatal conductance (1.01 mol/m²/s), fruit length (4.55 cm), fruit diameter (4.33 cm), number of fruits per plant (52.75), fruit yield (53.85 t/ha), ascorbic acid content (26.13 mg/100 g), zinc content in fruits (52.25 mg/kg), total zinc uptake (102.34 mg/plant), and a benefit-cost ratio of 3.39. Moreover, among the tested varieties, MT3 outperformed MT1. Therefore, a foliar application of 100 ppm ZnO-NPs is recommended as the optimal dose for tomato cultivation. This approach promotes healthier plants and superior fruit quality and supports more sustainable and productive agricultural practices while minimizing environmental harm. Additionally, further research is necessary to explore higher dosages of ZnO-NPs in tomato production to establish the best dose for optimizing output.

Conventional and Nano-Zinc Foliar Spray Strategies to Improve the Physico-Chemical Properties and Nutritional and Antioxidant Compounds of Timor Mango Fruits under Abiotic Stress

Zinc deficiency is common under heat stress, and further research is needed to determine how to enhance the fruit quality of mango trees through the use of three forms of zinc, namely Zn-NPs, zinc sulfate (ZnSO4), and chelated zinc (Zn-chelated), as a foliar spray. This research was carried out using ten treatments to investigate the effect of zinc forms on the fruit quality of Timor mango trees. With a few notable exceptions, every fruit quality measurement (physical characteristics, chemical properties, mineral contents, and antioxidant compounds) responded to every treatment looked into; however, the extent of the reaction differed depending on the fruiting measurement. Furthermore, the Zn-NPs created a larger difference in the fruiting measurements than the ZnSO4 and Zn-chelated forms. ZnO NPs at 100 ppm ranked first, followed by ZnO NPs in the first spray and zinc EDTA in the second spray, followed by ZnO NPs in the first spray and ZnSO4 in the second, for all mineral content and antioxidant compound measurements and most of the fruit physico-chemical characteristics. In contrast, the lowest levels of minerals and antioxidant compounds and most of the fruit physico-chemical characteristics were found in the controls. The outcomes of the other treatments after the three treatments lay somewhere between these two extremes, and this pattern was detected throughout two seasons. Spraying Timor mango trees with nano, chelated, and sulfate zinc can be considered a safe and environmentally friendly natural method for improving fruit quality in abiotic stress regions.

Hydrogen-rich water treatment maintains the quality and prolongs the shelf-life of postharvest table grapes by regulating respiratory and energy metabolisms

Background Table grapes suffer from a dramatic deterioration in quality, a reduction in shelf life and commercial value resulting from allivated postharvest respiratory metabolism and excessive energy consumption after harvest. Objective In this study, effects of hydrogen-rich water (HRW) on berry quality, respiratory metabolism, and energy level were investigated by multi concentration gradient tests (0% (control), 20%, 40%, 60%, 80%, and 100%). Methods To achieve this goal, by measuring fruit quality, respiratory metabolism, related enzyme activities, energy status, and other related indicators, to study its impact on postharvest fruit quality and further explore the mechanism of maintaining fruit quality after harvest. Results Compared to the control group, samples treated with HRW exhibited higher fruit firmness, total soluble solids (TSS), and titratable acids (TA), with the most prominent effect observed after treatment with 60% HRW. Compared with the control group, grapes treated with 60% HRW exhibited more effective regulation in the expression of GPI, AOX, SDH1, COX6a, G6DH, 6PGD, NADK, and AGPase gene, which helped maintain normal respiratory metabolism and energy levels in the fruit samples. Conclusions Our results showed that HRW treatment could potentially maintain the quality and prolong the shelf life of postharvest grapes by regulating gene expression and the activity of key enzymes involved in respiratory and energy metabolisms.

Assessing sugar composition and tissue structure indices of ‘Korla’ pear cortex using bulk optical properties in the 500–1500 nm

Optical measurement of fruit quality can provide the specific insights into the light absorption (μa) of chemical compositions and the multiple scattering (μs′) by structured tissues, and contributes to their precise evaluation. This work comprehensively explored the bulk optical properties (BOPs) in the wavelength range of 600–1500 nm related to the soluble sugars, pectin constitution and microstructural features (area, perimeter, Feret’s diameter, cell roundness, cell solidity and intercellular space) of ‘Korla’ pear cortex during post-harvest storage. The high correlation between μa values around 980 nm and 1 485 nm and total sugars and sucrose contents were observed with the r values from 0.74 to 0.99. The μs′ of pear tissues were positively corelated to the firmness, cell microstructure parameters in cortex (area, perimeter, Feret’s diameter and solidity), whereas negatively correlated to their cell roundness and intercellular properties. Besides, the partial least squares regression models based on the featured BOPs of pear cortex successfully predicted the total sugars and sucrose contents with the determination coefficients (Rp2) from 0.73 to 0.91. Further, the combined BOPs feature models based on the first component (PC1) scores of BOPs provide excellent prediction of firmness (Rp2 = 0.90) and acid soluble pectin (Rp2 = 0.93). Accordingly, this study indicated the optical properties have the possibility to present the sugar composition, firmness, pectin and microstructural characteristics of pear tissues.

"How sweet are your strawberries?": Predicting sugariness using non-destructive and affordable hardware.

Global soft fruit supply chains rely on trustworthy descriptions of product quality. However, crucial criteria such as sweetness and firmness cannot be accurately established without destroying the fruit. Since traditional alternatives are subjective assessments by human experts, it is desirable to obtain quality estimations in a consistent and non-destructive manner. The majority of research on fruit quality measurements analyzed fruits in the lab with uniform data collection. However, it is laborious and expensive to scale up to the level of the whole yield. The "harvest-first, analysis-second" method also comes too late to decide to adjust harvesting schedules. In this research, we validated our hypothesis of using in-field data acquirable via commodity hardware to obtain acceptable accuracies. The primary instance that the research concerns is the sugariness of strawberries, described by the juice's total soluble solid (TSS) content (unit: °Brix or Brix). We benchmarked the accuracy of strawberry Brix prediction using convolutional neural networks (CNN), variational autoencoders (VAE), principal component analysis (PCA), kernelized ridge regression (KRR), support vector regression (SVR), and multilayer perceptron (MLP), based on fusions of image data, environmental records, and plant load information, etc. Our results suggest that: (i) models trained by environment and plant load data can perform reliable prediction of aggregated Brix values, with the lowest RMSE at 0.59; (ii) using image data can further supplement the Brix predictions of individual fruits from (i), from 1.27 to as low up to 1.10, but they by themselves are not sufficiently reliable.

Hyperspectral imaging to measure apricot attributes during storage

The fruit industry needs rapid and non-destructive techniques to evaluate the quality of the products in the field and during the post-harvest phase. The soluble solids content (SSC), in terms of °Brix, and the flesh firmness (FF) are typical parameters used to measure fruit quality and maturity state. Hyperspectral imaging (HSI) is a powerful technique that combines image analysis and infrared spectroscopy. This study aimed to evaluate the potential of the application of the Vis/NIR push-broom hyperspectral imaging (400 to 1000 nm) to predict the firmness and the °Brix in apricots (180 samples) during storage (11 days). Partial least squares (PLS) and artificial neural networks (ANN) were used to develop predictive models. For the PLS, R2 values (test set) up to 0.85 (RMSEP=1.64 N) and 0.72 (RMSEP=0.51 °Brix) were obtained for the FF and SSC, respectively. Concerning the ANN, the best results in the test set were achieved for the FF (R2=0.85, RMSEP=1.50 N). The study showed the potential of the HSI technique as a non-destructive tool for measuring apricot quality even along the whole supply chain.

A method using near infrared hyperspectral imaging to highlight the internal quality of apple fruit slices

The heterogeneity of apple fruit was highlighted by near-infrared hyperspectral imaging (NIR-HSI) using a data analysis in two successive steps. First, NIR-HSI images were acquired on the cut surface of six transverse slices per apple, which were then systematically sampled with 5 or 6 cylinders per slice. PCA carried out on the NIR-HSI images allowed to select 141 representative cylinders from the total dataset (1056 samples), in which the contents of dry matter (DMC), total sugars (TSC), fructose, glucose, sucrose, malic acid and polyphenols were quantified by spectrophotometry and chromatography. In a second step, leave-one-out PLS models were developed and successfully used to describe the distribution of DMC (Rcv2 = 0.83, RPD = 2.39) and TSC (Rcv2 = 0.81, RPD = 2.20) in each apple slice. A strong heterogeneity of DMC and TSC was detected inside each fruit. Such a simple and rapid method reduced the needs of numerous chemical characterizations to demonstrate the distribution of quality traits within and between fruit and contributed to better manage the fruit quality measurements.

Non-destructive Measurement of Lycopene Content in High Soluble Solids Stored Tomato (Solanum Lycopersicum Mill. cv Rinka 409)

High-quality fruits can be produced by controlling the environmental factors, i.e. temperature, relative humidity, carbon dioxide, and light intensity. The tomato (Solanum lycopersicum) variety ‘Rinka 409’, was grown hydroponically with a high-wire system in high technology greenhouse, Ehime University, Japan. The water stress treatment using visual monitoring system was used to produce the high soluble solids tomato fruits. Moreover, a high lycopene content of tomato can be produced by controlling the storage condition. Non-destructive measurement has been known to provide a fast and accurate quality measurement of fruits and vegetables. The objectives of this study were to develop a precise position for the non-destructive measurement of the lycopene content in high soluble solids stored tomato using Vis/NIR spectroscopy and evaluate its performance. In this study, the high soluble solids of tomato fruits were grown under water stress treatment and stored after harvesting at 25°C in a cool incubator for 7 days. The tomato spectra were measured using Vis/NIR spectroscopy with the wavelength 500-1010 nm. The estimation of the lycopene content was based on the statistical model using multivariate analysis. From this study, it is concluded that the measurement of lycopene content in high soluble solids of tomato fruits after storage by using the top part of the tomato, was better than if it is compared to the side part. It was best determined using PLS analysis with Visible/Near-infrared Spectroscopy non-destructively, with the R 0.98 and RMSE 0.80.

Ultra-Low-Cost Self-Referencing Multispectral Detector for Non-Destructive Measurement of Fruit Quality

A very low-cost sensor is developed to non-destructively test fruits by sequentially turning on light-emitting diodes at 12 different wavelengths and measuring the reflectance in the interactance mode. The detector is tested on kiwifruit to measure soluble solids content (SSC) and dry matter (DM) non-destructively, while the performance is compared with a benchtop spectrometer. For SSC and DM measurements, a total of 378 and 200 samples of kiwifruits were measured respectively. Non-parametric regression was used for the multi-spectral detector, while a partial least squares regression model was used for the benchtop spectrometer. Different regression techniques were used as they provided the best prediction for the two different measurements. For SSC measurements, coefficient of determination (R2) of 0.83, root mean square error for prediction (RMSEP) of 0.85%, bias of −0.004%, and SDR of 2.45 were observed using the multispectral detector. The corresponding values achieved with the benchtop spectrometer were 0.98, 0.37%, 0.01%, and 5.60, respectively. For dry matter measurements with 200 kiwifruits, R2, RMSEP, bias, and SDR of 0.83, 0.61%, −0.02, and 2.44 were achieved with the prototype multispectral detector compared with the values of 0.96, 0.31%, −0.11, and 4.80, respectively, achieved with the benchtop spectrometer. The efficacy of the multispectral detector was also tested by measuring 30 navel oranges, wherein an R2 and root mean square error for calibration (RMSEC) of 0.79 and 0.47% were achieved for SSC measurements. While the performance of the multispectral detection is lower than a benchtop spectrometer, its performance is still better than low-cost spectrometers and can be used to inexpensively measure the quality of fruits in a non-destructive manner.

High performance ethylene sensor based on palladium-loaded tin oxide: Application in fruit quality detection

Ethylene (C2H4), as a plant hormone, its emission can be served as an indicator to measure fruit quality. Due to the limited physiochemical reactivity of C2H4, it is a challenge to develop high performance C2H4 sensors for fruit detection. Herein, this paper presents a resistive-type C2H4 sensor based on Pd-loaded tin oxide (SnO2). The C2H4 sensing performance of proposed sensor are tested at optimum operating temperature (250 °C) with ambient relative humidity (51.9% RH). The results show that the response of Pd-loaded SnO2 sensor (11.1, Ra/Rg) is about 3 times higher than that of pristine SnO2 (3.5) for 100 ppm C2H4. The response time is also significantly shortened from 7 s to 1 s compared with pristine SnO2. Especially, the Pd-loaded SnO2 sensor possesses good sensitivity (0.58 ppm−1) at low concentration (0.05–1 ppm) with excellent linearity (R2 = 0.9963) and low detection limit (50 ppb). The high sensing performance of Pd-loaded SnO2 are attributed to the excellent adsorption and catalysis effects of Pd nanoparticle. Meaningfully, the potential applications of C2H4 sensor are performed for monitoring the maturity and freshness of fruits, which presents a promising prospect in fruit quality evaluation.

Enhancing pollination is more effective than increased conventional agriculture inputs for improving watermelon yields.

Agricultural practices to improve yields in small‐scale farms in Africa usually focus on improving growing conditions for the crops by applying fertilizers, irrigation, and/or pesticides. This may, however, have limited effect on yield if the availability of effective pollinators is too low. In this study, we established an experiment to test whether soil fertility, soil moisture, and/or pollination was limiting watermelon (Citrullus lanatus) yields in Northern Tanzania. We subjected the experimental field to common farming practices while we treated selected plants with extrafertilizer applications, increased irrigation and/or extra pollination in a three‐way factorial experiment. One week before harvest, we assessed yield from each plant, quantified as the number of mature fruits and their weights. We also assessed fruit shape since this may affect the market price. For the first fruit ripening on each plant, we also assessed sugar content (brix) and flesh color as measures of fruit quality for human consumption. Extra pollination significantly increased the probability of a plant producing a second fruit of a size the farmer could sell at the market, and also the fruit sugar content, whereas additional fertilizer applications or increased irrigation did not improve yields. In addition, we did not find significant effects of increased fertilizer or watering on fruit sugar, weight, or color. We concluded that, insufficient pollination is limiting watermelon yields in our experiment and we suggest that this may be a common situation in sub‐Saharan Africa. It is therefore critically important that small‐scale farmers understand the role of pollinators and understand their importance for agricultural production. Agricultural policies to improve yields in developing countries should therefore also include measures to improve pollination services by giving education and advisory services to farmers on how to develop pollinator‐friendly habitats in agricultural landscapes.

Potential uses of LF‐NMR and MRI in the study of water dynamics and quality measurement of fruits and vegetables

This paper provides an overview of nondestructive imaging techniques for evaluating internal and external quality characteristics of fruits and vegetables and the future prospects of those technologies within the food industry. Low‐field nuclear magnetic resonance (LF‐NMR) and magnetic resonance imaging (MRI) are viable technologies in assessing water status, which can significantly impact the quality of fruits and vegetables' texture, tenderness, and microstructure. This review examined some of the most widely studied agricultural fruits and vegetables, described NMR/MRI techniques, and explained the benefits of their implementation in the assessment of internal quality attributes such as internal defects, water content, nutrition content, maturity, fruit firmness, and seed detection, as well as physicochemical and microbiological quality in both commercial and industrial applications. In spite of considerable developments in the quality measurement of fruits and vegetables and their products, the implementation of these techniques at an industrial level has been unsatisfactory. PRACTICAL APPLICATIONS: This paper aimed to present a magnificent knowledge about fruit/vegetable processing and preservation techniques pertaining to quality evaluation. If the appropriate skills and the introduced tools are combined and utilized in an innovative and suitable way, a high quality of fruit/vegetable products with a high nutritional value can be achieved. This will be beneficial for both producers and customers.

Non-Destructive Classification of Fruits Based on Vis-nir Spectroscopy and Principal Component Analysis

Fruits are one of the sources of nutrition needed for health. Fruit quality is generally assessed by physical and chemical properties. Measurement of fruit internal quality is usually done by destructive techniques. Ultraviolet, visible and near-infrared (UV-Vis-NIR) spec-troscopy is a non-destructive technique to measure fruit quality. This technique can rapidly measure the fruit quality, the measured fruit still remains intact, and can be marketed. Besides, UV-Vis-NIR spectrosco-py can also be used to classify fruits. The study aimed to classify var-ious types of fruits using UV-Vis-NIR spectroscopy with wavelengths of 300-1041 nm and Principal Component Analysis (PCA). First de-rivative savitzky-golay with 9 smoothing points (dg1) and multiplica-tive scatter correction (MSC) were applied to correct the spectra. The results showed that the use of uv-vis-nir spectroscopy and PCA com-bined with spectra pre-treatment of the MSC method were able to clas-sify various types of fruits with 100% success rate in all fruit samples including sapodilla, ridge gourd, mango, guava, apple and zucchini.

Implications of using two natural enemies of Tuta absoluta (Lepidoptera: Gelechiidae) toward tomato yield enhancement.

Tomato leaf miner (TLM), Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most destructive tomato pests worldwide. We tested quantity and quality of tomato fruits after simultaneous use of two biological control agents, the predatory mirid bug Nesidiocoris tenuis (Reuter) and the egg parasitoid Trichogramma brassicae Bezdenko against TLM. We varied the timing of predator releases (before or after pest establishment) and the number of parasitoids released (ten or 30 females per week per m2). The highest number of fruits per cage, percentage of undamaged fruits, total yield weight, and undamaged yield weight were all obtained with predator-in-first treatments, with or without parasitoid releases. Furthermore, measures of fruit quality were also highest in predator-in-first treatments, including, highest percentage of water, greatest proportional fresh weight of carbohydrates, most lycopene, most β-carotene, most flavonoids, and highest total chlorophyll. Thus, our findings support a predator-in-first augmentation approach for management of TLM.

In-row Vegetation-free Strip Width Effect on Established ‘Navaho’ Blackberry

AbstractA field study was conducted in 2014 and 2015 in an established 5-yr old commercial blackberry planting to determine the effect of vegetation-free strip width (VFSW) on ‘Navaho’ blackberry vegetative growth, yield and fruit quality parameters, identify the optimum VFSW for blackberry plantings in the southeastern USA, and provide practical groundcover management recommendations that can increase the productivity of blackberry plantings. In Fall 2013, tall fescue was seeded in-row and allowed to establish. In Spring 2014, VFSW treatments (0, 0.6, 0.9, 1.2, and 1.8 m) were established in a randomized complete block statistical design with four replications. Blackberry growth measurements included primocane and floricane number, cane diam, individual fruit weight and yield. Fruit quality measurements included, soluble solids concentration (SSC), titratable acidity (TA) and pH. Primocane number increased with increasing VFSW in both years. Floricane number increased with increasing VFSW in 2014. Primocane diam decreased with increasing VFSW in 2014 but had a quadratic response in 2015. Berry weight and cumulative yield increased with increasing VFSW in both years. The only berry quality component affected by VFSW was pH, which decreased as VFSW increased. Results indicate that widening the VFSW in blackberry from the current recommendation of 1.2 m to 1.8 m could provide growers a means to increase plant growth, berry weight, and cumulative yield blackberry of a planting.

Determination of optimal harvest boundaries for ‘Ambrosia’ apple fruit using a delta-absorbance meter

ABSTRACTIn this study, a new chlorophyll measurement tool, the delta absorbance (DA) meter, was used to develop an optimal harvest maturity model for ‘Ambrosia’ apple (Malus × domestica Borkh.) fruit. Fruit from four commercial orchards in the Annapolis Valley, Nova Scotia, Canada, were sampled (25 fruit from three or four trees per location) over nine consecutive weekly harvests during the 2011 and 2012 growing seasons, and 8 weeks in the 2013 season. At each harvest, five fruit from each orchard site had their index of absorbance difference (IAD) values, firmness, mass, titratable acidity (TA), soluble solids content (SSC), red skin colouration and internal core ethylene concentrations measured. Following approx. 3 months of storage at 3.5°C, 20 fruit from each site were removed and assessed for the incidence of disorders such as senescent breakdown, cortical browning and coreflush. Chlorophyll concentrations in the epidermis were strongly and positively related to IAD values in the same tissue (P ≤ 0.001), confirming the assumption that chlorophyll was the basis for the DA meter IAD signal. In addition, IAD values declined significantly during fruit maturity and were negatively related to harvest week (P ≤ 0.001). The optimum harvest period was identified by aligning all ‘at harvest’ IAD values, fruit quality measurements, and ‘post-storage’ disorder data with the corresponding harvest week. IAD values associated with harvests having the highest commercial fruit quality then delineated the optimal harvest boundaries. The upper boundary IAD value of 0.47 was defined as ‘when to begin harvest’, while the lower boundary IAD value of 0.28 was considered to be ‘when to end harvest’ for long-term storage. The use of a DA meter and its IAD value to define the optimal harvest boundaries may be applicable to all commercial apple cultivars, but should be developed for each cultivar and growing region.

Identification and analysis of anthocyanin components in fruit color variation inSchisandra chinensis.

Fruit color is an important index and parameter for measuring fruit quality. As an important pigment, anthocyanin is a determinant which appears in all sorts of colors of fruits in nature. Color parameters were measured using a spectrometer and used as a basis to divide the materials into three groups: reddish-orange, orange and yellow. A validated high-performance liquid chromatographic-electrospray ionization-mass spectrometric method was used for the analysis of anthocyanin in Schisandra chinensis and for determining major anthocyanin components in S. chinensis fruits, i.e. cyanidin xylosyl-glucoside (CyXylGlu), cyanidin glucosyl-rutinoside (CyGluRutin), cyanidin rutinoside (CyRutin) and cyanidin xylosyl-rutinoside (CyXylRutin). The anthocyanin contents vary obviously in different colored fruits in S. chinensis. The impact of anthocyanin on coloration of fruits was investigated by multiple regression analysis between color parameters and anthocyanin components, which indicated that CyRutin is the primary cause of fruit color variation in S. chinensis. The content and type of anthocyanin determine fruit coloration in S. chinensis, laying the early foundations for systematically interpreting the mechanism of fruit coloration in S. chinensis. © 2015 Society of Chemical Industry.

Improvement of fruit quality by moderate water deficit in three plum cultivars (Prunus salicinaL.) cultivated in a semi-arid region

Introduction. Drought can affect the qualitative and nutritional attributes of plum (Prunus salicina L.) . The aim of this work was to study the effect of regulated deficit irrigation (RDI) on the quality of plum fruits. Materials and methods. Experiments were conducted during two consecutive seasons (2011-2012) with three cultivars (‘Black Diamond’, ‘Black Gold’ and ‘Black Star’) recently introduced in the region of Regueb (center of Tunisia) characterized by a semi-arid climate. During the fruit growth period, treated trees (RDI 50) received 50% of the irrigation water provided to the control (CI) for three months. Results and discussion.Water restriction reduced the diameter and weight of the fruit though the extent depended on the cultivar. However, other measures of fruit quality were improved for all cultivars with an increase of fruit firmness, pH, soluble solids and sucrose content, and a decrease of total acidity. Additionally, ‘Black Diamond’ fruit from treated trees had high level of total phenolics and flavonoids. Conclusion. Regulated deficit irrigation may save water in semi-arid regions and improve fruit quality with only moderate impact on productivity.

Diagnosis of Agricultural Crops Using Light(<Feature>Control and Diagnosis by Light in Plant Production)

Measurement using light, for example, spectroscopy, is rapid, low cost and easy for maintenance of the instrument, and used for diagnosis of agricultural crops. Visible-near infrared method has been used non-destructively measuring color of leaf and near infrared method measuring fruit quality for practical use, respectively. On the other hand, infrared spectrophotometers have also evolved fourier transformation type. Therefore, ultraviolet, visible, near-infrared and infrared spectroscopy method is mainly described. Moreover, nitrate ions determination using light was also focused for mainly vegetables.

Exogenous onion extract hastens bud break, positively alters enzyme activity, hormone, amino acids and phenol contents, and improves fruit quality in ‘Anna’ apple trees

Metabolic changes in the activity of catalase, and the contents of hydrogen peroxide, proline, total free amino acids, total indoles, anthocyanins and free phenols in floral buds of apple (Malus domestica Borkh. cv. ‘Anna’) trees were investigated during dormancy and bud break under the effect of foliar application of two onion extract rates (100 and 200mll−1). Flowering percentage, fruit yield characteristics (i.e., fruit-set, number of fruits tree−1 and fruit yield tree−1) and fruit quality measurements were increased, while number of days recorded to reach full bloom were reduced with the application of both onion extract rates. In addition, contents of hydrogen peroxide, proline, total free amino acids, total indoles and anthocyanin were significantly increased in floral buds, particularly during bud break. In contrast, the activity of catalase and the content of free phenols were reduced. The best results were obtained from the extract rate of 200mll−1 that could be recommended for early and high percentage of flowering and increased yield with high quality by regulating the metabolism of amino acids, including proline and indoles, and the activities of catalase and hydrogen peroxide in apple floral buds.