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  • Open access
  • 57 Reads
Distinguishing Pickled and Fresh Cucumber Slices Using Digital Image Processing and Machine Learning

In the case of cucumber, postharvest challenges may focus on preserving the high quality and extending the shelf-life. Digital image analysis provides objective information about the quality of food products and the changes in the properties as a result of postharvest processing. This study was aimed at developing discriminative models for distinguishing the fresh and pickled cucumbers based on texture parameters of images to evaluate the effect of processing on the properties of cucumber flesh. The images for cucumbers immediately after harvest and the cucumbers preserved using a vinegar solution were obtained using a digital camera. Before the image acquisition, the cucumbers were sliced, which enabled the evaluation of the properties of the flesh. The slice images were processed in order to convert to individual color channels L, a, b, R, G, B, X, Y, Z and to extract image features. The discriminant analysis was carried out using selected classifiers from the following groups: Decision trees, Bayes, Rules, Functions, Lazy and Meta. The discriminative classifiers, such as Random Forest, LMT, Bayes Net, Naive Bayes, JRip, PART, Multilayer Perceptron, Logistic, KStar, IBk, Filtered Classifier and Multi Class Classifier were used. The analysis was carried out in one hundred repetitions (slices) for fresh cucumbers and one hundred repetitions (slices) for pickled cucumbers. The obtained results proved the effect of processing on image features of cucumber flesh. Including selected textures in the discriminative models allowed for the complete differentiation of fresh and processed samples. The fresh and pickled cucumbers were discriminated with an accuracy reaching 100% for selected color channels and classifiers. The application of digital image processing enabled the evaluation of changes in the flesh of cucumber subjected to postharvest processing.

  • Open access
  • 59 Reads
Evaluation of the postharvest quality of lacto-fermented radish using innovative discriminative models based on textures of images

Fermentation is one of the ways of preservation of fruit and vegetables. The objective of this study was to evaluate the changes in the textures of slice images of radish subjected to lacto-fermentation after harvesting. The effect of postharvest processing on the radish quality was evaluated using the innovative discriminative models built based on sets of selected textures of images acquired with the use of a digital camera and converted to color channels R, G, B, L, a, b, U, V, X, Y, Z. The models were developed for individual color channels and color spaces RGB, Lab, YUV, XYZ using discriminative classifiers, and were used to distinguish between fresh and lacto-fermented radishes. The accuracies of discrimination for fresh and lacto-fermented radishes, average accuracies for both samples, as well as TP Rate (True Positive Rate), Precision, F-Measure, ROC Area (Area Receiver Operating Characteristic Area) and PRC Area (Precision-Recall Area), were determined. The high values of these metrics indicated large changes in textures of lacto-fermented radishes compared to non-processed samples. The correctness of discrimination reached 100% in the case of models built for each color space and color channels R, B, b, U for selected classifiers (Logistic, Multi Class Classifier). In these cases, the values of TP Rate, Precision, F-Measure, ROC Area and PRC Area were equal to 1.000. The results demonstrated the effect of lacto-fermentation on the radish quality expressed in the changes in textures of images. The usefulness of image analysis for the evaluation of the postharvest processing of radish was also proven.

  • Open access
  • 112 Reads
Zinc biofortification of hydroponic mustard microgreens grown under different red and blue LED lighting ratios

Zinc (Zn) is important for different metabolic processes of the human body and controls different enzymatic processes, which are responsible for good human health. Zn deficiency in soil and plants and its low nutritional status in the population encourage studies on enrichment of agricultural products. Thus, the objective of this study was to evaluate the Zn doses applied to the hydroponic solution and to increase the concentration of this element in the microgreen of mustard (Brassica juncea ‘Red Lace’), depending on different blue–red (B:R) light ratios in light-emitting diode (LED) lighting. Mustards were grown hydroponically in controlled environment growth chambers under different B:R light ratios - 10%B:90%R, 75%B:25%R 10 days after sowing. A 220 µmol m-2 s-1 total photon flux density (TPFD), 18 h photoperiod, 21/17 ± 2 ºC temperature and 60% ± 5% relative humidity in the growth chamber were maintained during cultivation. The results showed that the Zn content in mustard increased with increasing Zn dose in hydroponic solution. The B:R ratio at 75%:25% resulted in higher Zn content in mustard compared to 10%B:90%R. Also, there was a tendency for higher Zn translocation factor at a higher percentage of B LED lighting. However, the higher percentage of B light and the increasing concentration of Zn in the solution, reduced the hypocotyl length and leaf area of mustard microgreens. The opposite results were obtained for mustards grown under 10%B:90%R lighting and increasing Zn in solution. The results suggest that the addition of Zn in a hydroponic solution and adapted LED lighting could be a suitable way for the cultivation of Zn-biofortified mustard microgreens. Acknowledgements: This project has received funding from the Research Council of Lithuania (LMTLT), agreement No. S-MIP-19-2.

  • Open access
  • 77 Reads
Raman spectroscopy as a useful tool in nutritional determination and distinction of Allium species

Allium species, especially Allium sativum or garlic, have been known for centuries, due their health benefits on human health. Phytochemicals present in these species exhibit numerous health effects that are well described in the scientific literature.

Raman spectroscopy combines with a microscope could give detailed information on the spatial distribution of different bioactive components of fresh food samples, and could give important insight in characterization and evaluation of the crops, widely known as plants for different agricultural applications. The application of modern spectroscopy methods gives us the opportunity to enrich the diet by examining new, poorly tested, Allium species that are a potential source of bioactive components.

Our study aimed to nutritional characterization and discrimination of Allium fistulosum (F), A. nutans (N), A. odorum (O), A. schoenoprasum (S), A. ampeloprasum var. ampeloprasum (AA), A. sativum var. sagittatum (SS) samples grown in Serbia. Selected Allium species were grown in open field conditions, from October 2018 to July 2019.

Samples were recorded using XploRA MicroRaman spectrometer at a 532 nm wavelength, spectra were preprocessed using Spectragryph software, and PCA was performed using PAST software.

According to raw vibrational spectra, onion samples are rich in carbohydrates, mostly pectin and cellulose as well as pectic acids, carotenoids, while the lower intensity bands indicated the attendance of proteinous structure.

Multivariate analysis, based on PCA, was applied in order to differentiate between the chemical compositions of six onion samples. The score plot of PC1 versus PC2 shows a reasonably good separation between the samples. The score plot suggests the existence of two groups of objects along PC1 axis (SK, NK, FK, OK and SSK, AAK). The loading plot shows that the variables with the positive contribution along PC1 axis corresponded to the signals at 754, 955, 1148, 1309, 1428 cm-1, indicated on polysaccharide, pectin, stretching vibration of glycosidic linkages while in the higher extend on the differences indicated band positioned at 1564 cm-1, probably directed to proteins. On the other side the signal at 1057 cm-1 is mostly responsible for the differentiation of SSK and AAK mainly depending on polysaccharide. According to PC2, FK, NK showed differences comparing to SSK and SK. The most influential parameters along PC2 axis corresponded to the signals at 1470 and 1516 cm-1, indicated on methyl ester groups in pectin and carotenoids.

Raman spectroscopy in a fast and noninvasive way could give preliminary discrimination in nutritional characteristics of six onion species grown in Serbia.

  • Open access
  • 44 Reads
Assessment of calcium content in pear fruits under storage after CaCl2 applications during pre and post-harvest phases

Post-harvest systems are crucial for fruit conservation since it minimizes the waste of such perishable food and allows its marketability to consumers during the year. This study thus aims to assess calcium values in stored fruits, previously sprayed and/or immersed in CaCl2, and possible implications on quality. Fruits previously sprayed with different concentrations of calcium chloride (0 – 8 kg.ha-1 CaCl2) during the productive cycle (pre-harvest phase) were separated into two groups at harvest. One was immediately stored in conservation chambers, while the second group was immersed in 1.3% CaCl2 (for 10 minutes at room temperature) in the post-harvest stage. After 4 months of storage, calcium content was evaluated with X-Ray fluorescence analysis and quality parameters, such as total soluble solids, malic acid, hardness, and colorimetric parameters of pulp were also monitored. Overall, calcium content in stored fruits with post-harvest bath were superior, but fruits with the exclusive application of CaCl2 during the pre-harvest phase were superior to the respective control. Furthermore, treatment T2 (corresponding to the highest concentration of CaCl2 during pre-harvest, up to 8 kg.ha-1) presented the lowest total soluble solids values. The highest value of malic acid prevailed in fruits with no application of CaCl2 while it also presented the lowest value of hardness. No significant differences were observed for colorimetric parameters of pulps. In conclusion, the pre-harvest workflow used for this study increased calcium content in fruits at harvest, but post-harvest immersion can be used in complementation to pre-harvest treatments to avoid fruit quality decay. Calcium applications did not compromise its marketability to consumers.

  • Open access
  • 73 Reads
Chemical characterization of different colored tomatoes: application of biochemical and spectroscopic tools

Tomato fruit quality is determined by a combination of different nutritive and health characteristics that are highly genotypic depend. Due to high demands for the products with improved nutritive and sensory attributes, traditional varieties are always a useful source of desirable characteristics. The aim of this study was to evaluate the fruit quality parameters in three traditional tomato genotypes with different colors: dark tomato, yellow tomato "Hilandarski" and pink tomato "Pirotski rozni". Tomatoes were grown in the open field conditions and morphological, biochemical and spectroscopic analysis were performed in ripe phase. The results indicated on characteristic genotypic differences in morphological as well as biochemical characteristics of the fruits. The yellow colored fruit tomato genotype had the highest content of soluble solids, organic acid, TSS/TTA ratio and vitamin C, but the lowest content of lycopene and b-carotene compared to other genotypes. Genotypic differences in the carotenoid content and components also confirmed by Raman spectroscopy. In the Raman spectra of the pericarp regions significant bands are mainly associated with carotenoid constituents and observed at 1507, 1147 and 997 cm-1 in dark and pink tomato genotypes and 1518, 1149 and 999 cm-1 in yellow tomato. PCA showed the characteristic response of the yellow genotype that was primarily related to the region of b-carotene and lycopene. The score plot of the pericarp regions of three tomatoes suggests the existence of two distinct clusters along the PC1 axis. The first one includes the pink and dark tomato fruit genotypes, while the yellow fruit genotype forms the second. The analyses indicated on the advantage of the yellow tomato genotype related to nutritional and sensory compounds compared to other genotypes, and his potential in a breeding program in order to improve traits related to consumer perception in new cultivars.

  • Open access
  • 318 Reads
The contribution of impact damage to the quality changes of stored banana fruits

Loss in fresh fruits mainly occurs due to their susceptibility to mechanical damage during the postharvest supply chain. Mechanical damages can reduce the quality of fresh produce during handling especially if they are not consumed directly, which is critical food safety and economic issue. Therefore, food security and agricultural efficiency require that vital action be taken to minimize such losses. The possible mitigation includes reducing the occurrence of damage by investigating the effects of the application of external forces during handling fresh fruits. Hence, this study is aiming to evaluate the local banana quality changes as affected by impact energy and forces resulted from the simulated handling practices during storage at 3 different temperature conditions for 12 days. Local banana fruits were damaged by low, medium, and high impact forces using the pendulum technique. Fruits from each impact energy were divided and stored at 5°C, 13°C, and 22°C. The changes in weight loss, texture, and color index were evaluated. The rate of transpiration was also determined. The results of the study showed a gradual reduction in weight loss in bananas impacted from the highest impact energy and stored at 22°C. The CIEL*a*b* color parameters changed during storage. chilling injuries were highly observed in banana fruits stored at 5°C in all damaged fruits. Storage at 13°C showed the least changes in texture properties of impacted bananas. Storage at 22°C and damage from the highest impact energy accelerated the increment of transpiration rate on banana fruits. Overall, one of the most key factors that reduce the incidence of severe damages occurred due to mechanical damages is storage management.

  • Open access
  • 67 Reads
Spent Cultivation Substrate (SCS) Management in circular farming system

Spent cultivation substrate (SCS) is growing medium which stays after cultivation of mushrooms or vegetables and for many years was considered as a problematic waste product from farming. However recently in the new transition to sustainable, circular farming systems it is seen as a valuable product which could be recycled. In the scope of the VegWaMus CirCrop project we have focused on recycling spent mushroom substrate (SMS) into growing medium or growing medium additives for vegetables and subsequent mushroom cultivation. We also investigated reuse spent growing substrate (SGS) and crop waste from greenhouse tomato production into new cultivation substrate via composting, vermicomposting and co-composting. The SMS after mushroom cultivation was firstly air dried or used in its fresh form for tomato and lettuce growing medium additive and was characterised by high organic matter content, low bulk density, high pH and soluble slats content. SMS substrates was rich in macro and micro elements important from nutritional point of view and their content generally decreased in following order K, Ca, Na, Mg, Mn, Fe, Si, Zn, Cu, Se and Mo. The content of heavy metals was acceptable.

Whereas SGS showed also acceptable heavy metals content, and could be potentially used in horticulture for subsequent greenhouse vegetables cultivation. However composting or co composting with additional waste products is recommended to eliminate potential pests and due to high mineral salt content. SGS has good composting potential with sufficiently high C/N ration and organic mater content (50-65%) to heat up during composting. SGS can be also targeted for the direct use in outdoor agriculture and landscaping as soil fertility amendment.

  • Open access
  • 43 Reads
Bioactivity of Monoterpene Alcohols as an Indicator of Biopesticidal Essential Oils against the Root Knot Nematode Meloidogyne ethiopica

Sustainable farming practices are becoming increasingly important, due to the need for a high yielding and zero carbon agriculture. Pesticide application remains one of the most efficient methods to control phytophagous parasites in crops. Yet, the use of pesticides has been subjected to tighter regulations as they can lead to substantial ecological and human health problems. Biopesticides present a sustainable alternative based on natural products with improved biocidal properties. Essential oils (EOs) are complex mixtures of highly active compounds that have previously shown to possess successful nematicidal activities. EOs are often mainly composed of terpenoids (mono- sesqui- and a few diterpenes) and phenylpropanoids. In the present work, the antinematodal activity of four pure monoterpene alcohols, which are generally found in high amounts on EOs of some aromatic and medicinal plants, was analyzed against the root knot nematode Meloidogyne ethiopica. Antinematodal activity was studied through direct contact bioassays, by adding ca. 50 nematodes to aqueous solutions of 1 mg/mL of geraniol, linalool, menthol or α-terpineol pure compounds. Toxicity was assessed by determining nematode mobility after 24, 48, 72 and 96 h. The monoterpene alcohols induced different responses in M. ethiopica throughout the time-course study. Geraniol induced complete immobility after 48h and maintained its activity throughout, while linalool reached its peak activity at 48 h and then decreased at 72 and 96 h. Menthol and α-terpineol had the highest activity at 24 h but decreased substantially throughout the time-course study. Geraniol showed an intense and lasting antinematodal activity against M. ethiopica, suggesting that EOs rich in this compound can be used in the development of nematicidal biopesticides to integrate sustainable pest management strategies.

  • Open access
  • 53 Reads
GPS-GIS Based Soil Fertility Maps of Shahada Tahsil of Nandurbar District (M.S.)

The GPS and GIS techniques i.e. (Global Position System and Geographical Information System) are widely utilized for delineating fertility maps of macro and micronutrients. Soil samples collected with GPS data can help in making critical decisions on nutrient management. Thematic soil fertility maps need the collection of soil samples using GPS technology. It is extremely important in agriculture for future soil nutrient monitoring in various locations/villages. Nandurbar district is located between 21.228 °N to 74.1422 °E North Latitude and East Longitude. Nandurbar district comprises six tahsils out of these the Shahada tahsil which is located between 21.5429691°N and 74.44691462 °E is considered for the study. Micronutrient depletion has become a serious limitation for soil productivity and sustainability due to the acceptance of high-yielding cultivars and intensive cropping, as well as a move toward the use of high NPK fertilizers. Latitude and Longitude were recorded by GPS instrument from soil sampling places of Shahada areas. The soils were collected at a depth of 0 to 22.5 cm from farmer’s fields. The samples collected from Shahada tahsil were 588. All the precautions were followed while processing the soil samples in the laboratory. Standard procedures, such as pH (1:2.5), electrical conductivity (EC) (1:2.5), and organic carbon in percentage, were used to analyze soil samples. The GPS-GIS based fertility maps of Shahada tahsil of Nandurbar district (M.S.) was prepared by using Arc-4 software. The cultivated soils of Shahada tahsil were alkaline in reaction. Soils of Shahada tahsil were moderately saline according to their electrical conductivity. The EC of soils ranged between 0.61-1.25 dSm-1 with an average value of 0.98 dSm-1. The average value of organic carbon in Shahada areas was 4.83 g kg -1. At Shahada 84.5 percent of cultivated soils are highly calcareous while 15.5 percent are medium calcareous. This data and fertility maps will be helpful in planning, maintaining the fertility, productivity, and quality of growing crops.

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