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Sugar beet leaves can be a viable and economically interesting source of high-quality protein for the food industry. We investigated how storage conditions and leaf wounding at harvest affect the content and quality of the soluble protein. After collection, leaves were either stored intact or shredded to mimic wounding induced by commercial leaf harvesters. Leaf material was stored in small volumes at different temperatures to assess leaf physiology or in larger volumes to assess temperature development at different locations in the bins. Protein degradation was more pronounced at higher storage temperatures. Wounding accelerated the degradation of soluble protein at all temperatures. Both wounding and storage at higher temperatures greatly stimulated respiration activity and heat production. At temperatures below 5°C, ribulose-1,5-biphosphate carboxylase oxygenase (RuBisCO) in intact leaves was preserved for up to 3 weeks. At temperatures of 30–40°C, RuBisCO degradation occurred within 48 h. Degradation was more pronounced in shredded leaves. In 0.8-m3 storage bins at ambient temperature, core temperatures rapidly increased, up to 25°C in intact leaves and up to 45°C in shredded leaves within 2–3 days. Immediate storage at 5°C greatly suppressed the temperature increase in intact but not in shredded leaves. The indirect effect of excessive wounding, that is, heat production, is discussed as the pivotal factor responsible for increased degradation of protein. For optimal retention of soluble protein levels and quality in harvested sugar beet leaves, it is advised to minimize wounding and to store the material at temperatures around −5°C. Practical Application: To preserve the soluble protein content and quality for at least 3 weeks, sugar beet leaves should be harvested with minimal wounding and stored at temperatures between 1 and 5°C. When aiming to store minimally wounded leaves in larger volumes, it must be ensured that the product temperature in the core of the biomass meets the temperature criterium or the cooling strategy must be adjusted. The principles of minimal wounding and low temperature storage are transferable to other leafy crops that are harvested for food protein.

In Northern Europe, potatoes are harvested at the end of the summer period and kept in large storage facilities for many months. Depending on the agreed delivery time, the demand of the market and/or the quality during storage, potatoes are sold. Higher quality potatoes, delivered at agreed delivery time, or at a time of high market demand, will lead to a higher price and thus more profit for the potato grower. One of the important quality issues during storage is the development of rot, often caused by infection with bacteria belonging to the family of Pectobacteriaceae, causing soft rot (Pectobacterium and Dickeya species). Initial infection can spread to neighboring tubers and therefore trigger a wide infection. Such infections can start anywhere in a potato pile and are thus not always immediately visible, leading to extensive product losses. Respiration and volatile production of healthy, wounded and soft rot-infected potatoes were measured over time using GC and PTR-ToF-MS. We observed that both the respiration, as well as the production of specific volatiles increases significantly in potatoes infected by Pectobacterium polaris. This indicates that there is a potential to use the respiration and volatile-profile as biomarkers for early and remote detection of rot in potato. This would allow growers to take action by adjusting the storage regime to prevent further spread of infection and extend the storage of the healthy potatoes. Depending on the demand on the market, growers could also decide to bring batches showing no signs of infection to the market while the quality is still acceptable, thereby increasing profit for the grower.

The relations between physical and chemical characteristics (e.g., color, firmness, volatile and non-volatile metabolites) of red ripe strawberry fruit and the natural spoilage caused by Botrytis cinerea were investigated. The spoilage rates differed between genotypes, and this was highly correlated over two successive years. Among seventeen genotypes, a more intense red coloration of the fruit skin was associated with a lower spoilage rate (r = –0.63). Additionally, weakly negative correlations were found between the levels of anthocyanins, ascorbic acid, malic acid and spoilage rates. No clear correlations were found between spoilage rates and soluble sugars, most volatiles, firmness and dry weight percentage. High levels of two volatile compounds, ethyl butanoate (r = 0.55) and 1-hexanol (r = 0.61), were correlated to high spoilage rates. These characteristics may assist strawberry breeders in selecting for genotypes with reduced susceptibility to B. cinerea.

This study aims to test the hypothesis that skin dehydration can cause the development of cork-like layers in the avocado fruit skin which may negatively affect Vis-NIR spectroscopy. To test this, dehydration treatment was applied on avocado fruit by storing them at low relative humidity (RH) during ripening treatment. Furthermore, to demonstrate that the hypothesis was not only valid for a single instrument and in general valid for any type of Vis-NIR instrument the avocados were also measured with two different spectrometers i.e., lab-based, and hand-held. Since the two instruments have two different measurement geometries i.e., diffuse reflection and interaction, the study also tests which geometry was best for the measurement of DMC in dehydrated avocados. The results showed that the dehydration of avocado fruit negatively affects the performance of Vis-NIR calibrations compared to the non-dehydrated fruit. The root mean squared error of cross-validation (RMSEcv) on internal test set for dehydrated and non-dehydrated fruit were up to 1.49 % dw/fw and 1.02 % dw/fw, respectively. The hypothesis was true for both lab-based and hand-held instruments, and the root mean squared error of prediction on internal test set were up to 28 % higher for dehydrated fruits. The performance of interaction measurement mode was better (RMSEcv = 0.98 % dw/fw) than the diffuse reflection mode (RMSEcv = 1.21 % dw/fw) for non-dehydrated fruit, however, both modes achieved similar performance (RMSEcv = ∼1.42 % dw/fw) for dehydrated fruit. The poorer performance of Vis-NIR models on dehydrated avocado fruit can be accepted as a limitation of Vis-NIR spectroscopy for avocado fruit analysis.

Background: Certain food bioactives and nutraceuticals need to be preserved from environmental factors such as pH, light, oxygen, temperature, and enzymatic degradation because they are chemically or physically instable. Moreover, these compounds may be degraded in gastrointestinal system and are not absorbed in body. Being a novel technique, encapsulation suggested effective solution to the limitations of delivering intact bioactive ingredients to the target sites. Chitosan has been extensively valued as a delivery system for bioactive ingredients. Scope and approach: In this review article, we discuss the potential applications of chitosan-based carriers as encapsulating agent in food industry. Chitosan alone or modified chitosan particles have been extensively used as a coating on liposome and alginate beads, as well as a delivery system for bioactive ingredients such as essential oils, flavor, vitamins, antioxidants, and probiotics. Key findings and conclusions: Chitosan is a cationic natural polysaccharide which has emerged as a suitable carrier in delivering nutraceuticals as it is non-toxic, biodegradable and biocompatible. Chitosan encapsulation can protect bioactive ingredients from extreme conditions such as pH and temperature. Chitosan capsules have proved to be suitable carriers for essential oils, flavors, vitamins, antioxidants, and probiotics.

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Tomato is an important commercial product which is perishable by nature and highly susceptible to fungal incidence once it is harvested. Not all tomatoes are equally vulnerable to pathogenic fungi, and an early detection of the vulnerable ones can help in taking timely preventive actions, ranging from isolating tomato batches to adjusting storage conditions, but also in making right business decisions like dynamic pricing based on quality or better shelf life estimate. More importantly, early detection of vulnerable produce can help in taking timely actions to minimize potential post-harvest losses. This paper investigates Near-infrared (NIR) hyperspectral imaging (1000–1700 nm) and machine learning to build models to automatically predict the susceptibility of sepals of recently harvested tomatoes to future fungal infections. Hyperspectral images of newly harvested tomatoes (cultivar Brioso) from 5 different growers were acquired before the onset of any visible fungal infection. After imaging, the tomatoes were placed under controlled conditions suited for fungal germination and growth for a 4-day period, and then imaged using normal color cameras. All sepals in the color images were ranked for fungal severity using crowdsourcing, and the final severity of each sepal was fused using principal component analysis. A novel hyperspectral data processing pipeline is presented which was used to automatically segment the tomato sepals from spectral images with multiple tomatoes connected via a truss. The key modelling question addressed in this research is whether there is a correlation between the hyperspectral data captured at harvest and the fungal infection observed 4 days later. Using 10-fold and group k-fold cross-validation, XG-Boost and Random Forest based regression models were trained on the features derived from the hyperspectral data corresponding to each sepal in the training set and tested on hold out test set. The best model found a Pearson correlation of 0.837, showing that there is strong linear correlation between the NIR spectra and the future fungal severity of the sepal. The sepal specific predictions were aggregated to predict the susceptibility of individual tomatoes, and a correlation of 0.92 was found. Besides modelling, focus is also on model interpretation, particularly to understand which spectral features are most relevant to model prediction. Two approaches to model interpretation were explored, feature importance and SHAP (SHapley Additive exPlanations), resulting in similar conclusions that the NIR range between 1390–1420 nm contributes most to the model’s final decision.

Anthurium (Anthurium andraeanum L.) is a cold-sensitive species originating from the tropical region of the world. This plant is widely cultivated all around the globe for the beauty of its ornamental spathes. Here, the effect of light quality on water loss of cut anthurium flowers was tested under chilling conditions. Cut flowers of two anthurium cultivars, ‘Calore’ (red spathe) and ‘Angel’ (withe spathe), were exposed to a cold temperature (4°C) under different light spectra, including darkness (D), red (R), blue (B), 7:3 ratio of red:blue (RB), and white (W). The results showed that ‘Angel’ flowers under the B light spectrum had the lowest relative water content (RWC) and specific surface area. It also showed the lowest spathe water content on a dry weight basis. The lowest vase life was obtained for ‘Angel’ under the B light spectrum, while the longest vase life was obtained under the R light, for both studied cultivars. Under the B light treatment, more open stomata were observed. Accordingly, the highest water loss was observed in all treatments with the B light, and the lowest percentage of water loss was observed in the D and R light, especially in ‘Angel’ flowers. In conclusion, the B light spectrum negatively influences vase life of cut anthurium flowers, through its effect on water relations of the spathes.

This study was conducted with the aim of providing the latest situation on banana genotypic diversity present in the market places, their cultivations, their market chain and trading facilities in Maluku Province, Indonesia. A survey method was used, in which different markets, farmers and government institutions were visited and interviewed. Seventeen genotypes of three different species and different genome and ploidy levels were found at the market places with two highly demanded genotypes, Pisang Raja Hitam and Pisang 40 Hari. The major suppliers of banana commodities in Ambon markets were Ceram, Ambon, Buru, Obi and Bacan Islands. Lack of knowledge in implementing proper cultural practices, lack of capital, lack of aid provided by government and several other obstacles have been the reasons for low banana production in Maluku Province. Lack of sufficient infra-structure for large scale cultivations, storage and transport, and the use of harmful chemicals in post-harvest handling were some of the factors potentially hindering international trading of banana products. However, there were development plans by the government, which possibly improve banana export situation in the future. As an initial study in terms of value chain analysis in the province, the study should be a reference for further studies of such. Key words: Banana, plantain, market place, Ambon Island, non-Cavendish, international trading.

To investigate the importance of light on healing and acclimatization, in the present study, grafted watermelon seedlings were exposed to darkness (D) or light, provided by blue (B), red (R), a mixture of R (68%) and B (RB), or white (W, 35% B, 49% intermediate spectra, 16% R) LEDs for 12 days. Survival ratio, root and shoot growth, soluble carbohydrate content, photosynthetic pigments content, and photosynthetic performance were evaluated. Seedling survival was not only strongly limited in D but the survived seedlings had an inferior shoot and root development, reduced chlorophyll content, and attenuated photosynthetic efficiency. RB-exposed seedlings had a less-developed root system. R-exposed seedlings showed leaf epinasty, and had the smallest leaf area, reduced chlorophyll content, and suppressed photosynthetic apparatus performance. The R-exposed seedlings contained the highest amount of soluble carbohydrate and together with D-exposed seedlings the lowest amount of chlorophyll in their scions. B-exposed seedlings showed the highest chlorophyll content and improved overall PSII photosynthetic functioning. W-exposed seedling had the largest leaf area, and closely resembled the photosynthetic properties of RB-exposed seedlings. We assume that, during healing of grafted seedlings monochromatic R light should be avoided. Instead, W and monochromatic B light may be willingly adopted due to their promoting effect on shoot, pigments content, and photosynthetic efficiency.

We investigated the effects of low oxygen storage on chilling injury development, colour development, respiration and H2O2 levels of ‘Merlice’ tomatoes cultivated with and without far red (FR) LED lighting during 20 days of shelf-life. Mature green (MG) and red (R) tomatoes were stored at 2 °C in combination with 0.5, 2.5, 5 and 21 kPa O2 for 15 days (experiment 1). MG tomatoes cultivated under either white LED or white LED light with FR LED light were stored at 2 °C in combination with 1, 5 and 21 O2 kPa for 14 days (experiment 2). Chilled MG and R tomatoes from experiment 1 showed decay, firmness loss and higher weight loss during shelf-life which were reduced under low oxygen conditions. FR during cultivation improved chilling tolerance of MG tomatoes. Fastest colour development and lowest respiration rate during shelf-life were observed for MG fruit cultivated with FR lighting prior to storage at 1 kPa O2/0 kPa CO2. H2O2 levels during the shelf-life were not affected during cold storage. The improved cold tolerance of MG tomatoes cultivated with FR lighting is likely due to lower oxygen uptake that led to both higher lycopene synthesis and less softening.

Near-infrared (NIR) spectroscopy models for fresh fruit quality prediction often fail when used on a new batch or scenario having new variability which was absent in the primary calibration. To handle the new variability often model updating is required. In this study, to solve the challenge of updating NIR models related to fresh fruit quality properties, the use of a semi-supervised parameter-free calibration enhancement (PFCE) approach was proposed. Model updating with PFCE was shown in two ways: first where the model on the primary batch was updated individually for each new fruit batch, and second where the model was sequentially updated for the next batches. Furthermore, for the first time, a case of updating an instrument transferred model was also presented. The PFCE approach was shown in two real cases related to moisture and total soluble solids prediction in pear and kiwi fruit. In the case of pear, the model was later updated for 3 new measurement batches, while, for kiwi, a commercial model was updated to incorporate the variability of a new experiment carried out with a new instrument in the laboratory environment. For each modelling demonstration, the performance was benchmarked with the partial least-square (PLS) regression analysis on the primary batch. The results showed that the models updated with a semi-supervised approach kept a high predictive performance on new measurement batches, without any extra parameter optimization. An instrument transferred model was also updated to maintain its performance on different batches. Further, the sequential updating approach was found to be performing better than the update for individual batches, as the models were able to learn from multiple batches. Model updating with a semi-supervised approach can allow the NIR spectroscopy of fresh fruit to be scalable, where models can be shared between scientific or application community.

Digital rice phenotyping requires rapid assessment of protein content of rice to kernels to support high-throughput crop phenotyping experiments. A fast and non-destructive approach can allow rapid decision making to breed and select relevant rice varieties. Hence, this study compares the predictive potential of near-infrared (NIR) spectroscopy for three physical forms of rice i.e., rice kernel (with glume), whole grain brown rice and powdered rice. The aim is to identify the best physical form to be adapted in future use for high-throughput protein content prediction in rice samples. The models were optimized by selecting key wavelengths most correlated to the protein content in rice. For variable selection, a total of 8 recently developed chemometric variable selection techniques were used. As a baseline comparison to variable selection techniques, partial-least square (PLS) regression analysis was used. The results showed that for all forms of rice samples, variable selection improved the predictive performance compared to the PLS regression modelling. The best accuracies were obtained for the brown rice samples with a prediction error of 0.349%. Further, this was achieved with only 12 wavelengths compared to the 304 wavelengths available in the original data set. Based on the results, this study indicates that there is no need to grind the rice samples into powder for using NIR spectroscopy. Hence, NIR spectroscopy can directly be used on brown rice samples and can support the rapid assessment of protein content in rice to support digital phenotyping.

International audience; Near infrared (NIR) spectroscopy allows rapid estimation of quality traits in fresh fruit. Several portable spectrometers are available in the market as a low-cost solution to perform NIR spectroscopy. However, portable spectrometers, being lower in cost than a benchtop counterpart, do not cover the complete near infrared (NIR) spectral range. Often portable sensors either use silicon-based visible and NIR detector to cover 400–1000 nm, or InGaAs-based short wave infrared (SWIR) detector covering the 900–1700 nm. However, these two spectral regions carry complementary information, since the 400–1000 nm interval captures the color and 3rd overtones of most functional group vibrations, while the 1st and the 2nd overtones of the same transitions fall in the 1000–1700 nm range. To exploit such complementarity, sequential data fusion strategies were used to fuse the data from two portable spectrometers, i.e., Felix F750 (~400–1000 nm) and the DLP NIR Scan Nano (~900–1700 nm). In particular, two different sequential fusion approaches were used, namely sequential orthogonalized partial-least squares (SO-PLS) regression and sequential orthogonalized covariate selection (SO-CovSel). SO-PLS improved the prediction of moisture content (MC) and soluble solids content (SSC) in pear fruit, leading to an accuracy which was not obtainable with models built on any of the two spectral data set individually. Instead, SO-CovSel was used to select the key wavelengths from both the spectral ranges mostly correlated to quality parameters of pear fruit. Sequential fusion of the data from the two portable spectrometers led to an improved model prediction (higher R2 and lower RMSEP) of MC and SSC in pear fruit: compared to the models built with the DLP NIR Scan Nano (the worst individual block) where SO-PLS showed an increase in R2p up to 56% and a corresponding 47% decrease in RMSEP. Differences were less pronounced to the use of Felix data alone, but still the R2p was increased by 2.5% and the RMSEP was reduced by 6.5%. Sequential data fusion is not limited to NIR data but it can be considered as a general tool for integrating information from multiple sensors.

This study utilizes advanced wavenumber selection techniques to improve the prediction of amylose content in grounded rice samples with near-infrared spectroscopy. Four different wavenumber selection techniques, i.e. covariate selection (CovSel), variable combination population analysis (VCPA), bootstrapping soft shrinkage (BOSS) and variable combination population analysis-iteratively retains informative variables (VCPA-IRIV), were used for model optimization and key wavenumbers selection. The results of the several wavenumber selection techniques were compared with the predictions reported previously on the same data set. All the four wavenumber selection techniques improved the predictive performance of amylose in rice samples. The best performance was obtained with VCPA, where, with only 11 wavenumbers-based model, the prediction error was reduced by 19% compared to what reported previously on the same data set. The selected wavenumbers can help in development of low-cost multi-spectral sensors for amylose prediction in rice samples.

This study aims to utilize non-destructive sensing based on Vis-NIR spectroscopy and acoustic to predict firmness of avocado fruit. The study has three aims, the first aim was to find the best reference firmness measurement technique for calibrating Vis-NIR spectroscopy data related to avocado ripening i.e., acoustic firmness (AF), limited compression (LC) and penetrometer max force (Fmax). The second aim was to study the generalizability of Vis-NIR models with respect to the dehydration level of avocado fruits. Dehydration of outer skin during storage is common and may cause model failure as the Vis-NIR signal is dominated by signal corresponding to high moisture in fresh fruit. The third aim was to fuse the Vis-NIR spectroscopy and acoustic information to improve the prediction of the LC and Fmax, otherwise unattainable with a single technique. The results showed that the best models for firmness prediction were obtained with LC as the reference. The avocado skin dehydration negatively affected the performance of Vis-NIR models to predict firmness. Further, a fusion of Vis-NIR spectroscopy and acoustic information improved prediction (reduced error by 21%) of firmness in avocado. Assessing avocado firmness in a multi-sensor framework can allow to precisely access the ripeness stage of avocados.

The aim of this study was to compare a laboratory-based and a pocket-sized near-infrared (NIR) spectrophotometer (SCiO) to predict mango fruit firmness. Three batches of mango fruit were measured to explore batch specific and global models. To gain insight to useful wavelengths important for predicting mango firmness variables, the bootstrapping soft shrinkage (BOSS) variable selection routine was used. Modelling was performed with partial least-squares regression (PLSR). The reference firmness measurements were performed with AWETA acoustic firmness analyser. The SCiO and the laboratory-based instrument showed similar performances predicting the reference firmness in terms of prediction coefficient of determination (R2). However, the root mean squared error of prediction (RMSEP) was slightly lower for the laboratory-based instrument compared to the SCiO, likely because a broader spectral region was used. The performance of the batch specific models was improved by up to 8 % in R2 with a 13 % reduction in RMSEP when BOSS was applied. For both laboratory based and SCiO, the global models based on combined data from the three batches, showed good performance (R2 0.74-0.93, RMSEP 4.8 – 8.2 Hz2g2/3 depending on the batch) to predict the firmness. Due to comparable performance of the SCiO compared to the laboratory-based spectrophotometer, the pocket-sized SCiO NIR sensor has the potential to become a low-cost, easy to use non-destructive tool to measure firmness in mango fruit.

Harvesting strawberry fruit before they are fully ripe and allowing them to further ripen during postharvest cold storage is a common practice. The effect of these storage conditions on consumer liking is not well understood. The first aim of this study is to investigate the effects of maturity at harvest and subsequent cold storage on consumer liking, expressed as sweetness and aroma attributes, and volatile composition. The second aim of this study is to investigate whether volatile organic compounds (VOCs) can be used to predict consumer liking. Strawberries (Fragaria × ananassa cv. Lusa) were harvested either at the ¾ red stage or full red stage and stored at 4 °C for one, five or nine days. Strawberries were subjected to sensory profiling, colour-, firmness-, GC–MS- and PTR-ToF-MS- measurements. The sensory profile of strawberries harvested at ¾ red stage showed lower sweetness and aroma than full red harvested strawberries. VOC analysis of these strawberries showed lower presence of volatile fatty acids, furanones and most esters even after nine days of cold storage, compared to full red strawberries. Strawberries harvested at full red stage showed the highest value for aroma attributes after one day of cold storage. Surprisingly, peak intensities of most esters (except for methyl butanoate and methyl hexanoate) and furanones were low on the first day, compared to ripe harvested fruit after longer storage. Ripe harvested fruit stored for nine days showed the highest peak intensities for most VOCs, but this did not correspond to the highest sensory aroma attributes. These fruits were judged with the lowest values for aroma attributes, perhaps related to the production of volatiles with off-flavours (acetaldehyde, ethyl acetate). PLS modelling showed that VOCs exist that are characteristic for both sweet and aromatic sensory attributes of ‘Lusa’ strawberries, based either on GC–MS (mainly volatile fatty acids) or PTR-ToF-MS analysis (mainly alcohol/ester fragments). This could lead to fast, non-destructive, selection of strawberries with high consumer liking using PTR-ToF-MS.

Light emitting diodes (LEDs) now enable precise light quality control. Prior to commercialisation however, the plant response to the resultant light quality regime ought to be addressed. The response was examined here in chrysanthemum by evaluating growth, chlorophyll fluorescence (before and following water deficit), as well as stomatal anatomy (density, size, pore dimensions and aperture heterogeneity) and closing ability. Plants were grown under blue (B), red (R), a mixture of R (70%) and B (RB), or white (W; 41% B, 39% intermediate spectrum, 20% R) light LEDs. Although R light promoted growth, it also caused leaf deformation (epinasty) and disturbed the photosynthetic electron transport system. The largest stomatal size was noted following growth under B light, whereas the smallest under R light. The largest stomatal density was observed under W light. Monochromatic R light stimulated both the rate and the degree of stomatal closure in response to desiccation compared with the other light regimes. We conclude that stomatal size is mainly controlled by the B spectrum, whereas a broader spectral range is important for determining stomatal density. Monochromatic R light enhanced stomatal ability to regulate water loss upon desiccation.

Near-infrared spectroscopy (NIRS) is a key non-destructive technique for rapid assessment of the chemical properties of food materials. However, a major challenge with NIRS is the mixed physicochemical phenomena captured by the interaction of the light with the matter. The interaction often results in both absorption and scattering of the light. The overall NIRS signal therefore contains information related to the two phenomena mixed. To predict chemical properties such as dry matter, Brix and lipids, light refelction/absorption is used. Therefore, when the aim of the data analysis is to predict chemical components, it is necessary to remove as much as possible the scattering effects from the spectra. Several pre-processing techniques are available to do this, but it is often difficult to decide which one to choose. In this article we present the use of a recently developed pre-processing approach, sequential pre-processing through orthogonalization (SPORT), to improve the predictive power of multivariate models based on NIR spectra of food materials. The SPORT approach utilizes sequential orthogonalized partial least square regression (SOPLS) for the fusion of data blocks corresponding to several spectral preprocessing techniques. The results were compared with commonly used pre-processing techniques in the analysis of food materials by NIRS. The comparison was made by analyzing 5 different datasets comprised of apples, apricots, olive oils and grapes associated with chemical properties such as dry matter (DM), Brix, lipids and citric acid. The datasets were from both reflection and transmission measurements. The results showed that the fusion-based pre-processing methodology is an ideal choice for pre-processing of NIRS data. For four out of five datasets, the prediction accuracies (high R2pred and low RMSEP) were improved. The improvement led to as much as a 20 % increase in R2pred and a 25 % decrease in RMSEP compared to the standard 2nd derivative pre-processing. The pre-processing fusion was more effective for the reflection mode compared to the transmission mode. Multiple pre-processing techniques provided complementary information, and therefore, their fusion using the SPORT approach improved the model performance. The methodology is not only applicable to food materials but can in fact be used as a general pre-processing approach for all types of modeling of spectral data.

Metabolic profiles of tomatoes change during ripening and light can modulate the activity of relevant biochemical pathways. We investigated the effects of light directly supplied to the fruits on the metabolome of the fruit pericarp during ripening. Mature green tomatoes were exposed to well-controlled conditions with light as the only varying factor; control fruits were kept in darkness. In experiment 1 the fruits were exposed to either white light or darkness for 15 days. In experiment 2, fruits were exposed to different light spectra (blue, green, red, far-red, white) added to white background light for seven days. Changes in the global metabolome of the fruit pericarp were monitored using LCMS and GCMS (554 compounds in total). Health-beneficial compounds (carotenoids, flavonoids, tocopherols and phenolic acids) accumulated faster under white light compared to darkness, while alkaloids and chlorophylls decreased faster. Light also changed the levels of taste-related metabolites including glutamate and malate. The light spectrum treatments indicated that the addition of blue light was the most effective treatment in altering the fruit metabolome. We conclude that light during ripening of tomatoes can have various effects on the metabolome and may help with shaping the levels of key compounds involved in various fruit quality characteristics.

Sliced tomatoes soften rapidly as well as becoming translucent. To develop a physiologically-based mechanism to describe softening the firmness of two cultivars, as a function of time, storage temperature, type of compression (repeated on the same spot or single measurements on consecutive spots on the equator of the pericarp) and initial maturity was measured using tomato slices. The proposed mechanism assumes that the softening of slices is radically different from that of whole tomatoes and depends on the stage of ripening at slicing. The mechanism is also based on the assumption that the pericarp solubility will quickly increase because of exposure to, amongst others, vacuolar contents with a low pH. This exposure will have a more serious effect on the firmness behaviour of ripe tomatoes because the pericarp tissue will have been exposed longer to a lower pH environment that will affect pectin solubility. A kinetic model that describes the individual firmness behaviour over time was developed. This model described trends well despite the high variability of the raw data. It was found that firmness loss induced by wounding occurs within 12 h. The effect of the initial maturity on the final firmness of the slices was large. The model indicates that consumer acceptance of sliced tomatoes is greatly affected by selection of cultivars with sufficient final (structural) firmness combined with a thorough assessment of the maturity at the time of slice preparation.

Since cucumbers suffer from a short postharvest life, applying different technologies is increasingly used as effective ways to increase their shelf life and quality. In this study a combination of chitosan-limonene coating and MAP storage has been used as a postharvest treatment to maintain cucumber quality. Samples were stored in three different packages: A (21% O2, macro-perforated package to be in equilibrium with air); package B (active MAP, starting concentrations 10% O2 + 5% CO2); package C (passive MAP starting concentrations 21% O2 + 0.1% CO2); they were stored at three temperatures (20, 10, and 4 °C). Quality parameters of cucumber such as weight loss, firmness, color, pH, fungal growth, Tg, organoleptic properties were determined. Interactive effects of coating, package, temperature, and storage time showed that coating and MAP in general had positive effects on several quality aspects. Coating combined with active MAP had the most positive effect on most postharvest attributes. However, using active MAP at higher temperature led to quality problems and is only useful if storage time is short. The combined usage of active MAP and chitosan-based coating on cucumber represents an innovative and interesting method for commercial application.

l -ascorbate (vitamin C, ASC) is an antioxidant that is essential for the proper function not only of plants but also animals. Light is a major regulatory factor for ASC levels in plants. In this paper, we review the regulation of ASC by light and the involved biochemical and physiological processes. Several biochemical pathways for ASC biosynthesis have been proposed to exist in plants. We aim to determine the contribution of these biochemical pathways on ASC levels and, locate the steps of them that are affected by light. From biochemical and genetic studies only evidence for ASC biosynthesis occurring via the d -mannose/L-galactose biosynthetic pathway was found. Alternative pathways might account for ASC biosynthesis only in transgenic plants. Apart from biosynthesis, recycling and turnover of ASC might affect the size of the ASC pool. Light regulation of ASC levels in plants occurs primarily via effects on biosynthesis. In addition, light affects ASC homeostasis and translocation within the plant. Light regulation of ASC has been studied for individual physiological processes without taking into account possible interactions. By establishing the physiological network behind light regulation of ASC for both leaves and fruit, we developed a novel hypothesis on interactions between the physiological processes that regulate ASC. We conclude that respiration and photosynthesis interact in light regulation of ASC biosynthesis via carbohydrate availability.

Basil suffers from chilling injury (CI) when stored at temperatures below 10–12 °C which seems related to the imbalance between reactive oxygen species (ROS) and antioxidants. We hypothesized that increased light intensity applied shortly before harvest (EOP, End-Of-Production) increases nutritional value i.e. carbohydrates and antioxidants and could improve the chilling tolerance. Two basil cultivars were grown in a vertical farming set-up at a light intensity of 150 µmol m−2 s−1. During the last 5 days of growth, EOP light treatments ranging from 50 to 600 µmol m−2 s−1 were applied. After harvest the leaves were stored at 4 or 12 °C in darkness. Higher EOP light intensity increased the antioxidant (total ascorbic acid, rosmarinic acid) and carbohydrate contents at harvest. During storage antioxidants decreased more rapidly at 4 than at 12 °C. However, increased EOP light intensity did not alleviate chilling symptoms suggesting a minor role of antioxidants studied against chilling stress.

In this work, the involvement of programmed cell death (PCD) in the wound-induced postharvest browning disorder and senescence in butterhead lettuce (Lactuca sativa L.) fresh-cuts was studied. At the wounded (cut, bruised) sites, rapid browning, loss of chlorophyll and massive cell death, accompanied with accumulation of reactive oxygen species and increased electrolyte leakage occurred in a narrow strip of tissue adjacent the injury. The dead cell morphology (protoplast and nuclei shrinkage) together with the biochemical and physiological changes resembled necrotic PCD type. With a slight delay post-wounding, senescence associated with similar cell death features was initiated in distant non-wounded sites. In addition to necrotic PCD, both in wounded and senescing tissue, the appearance of empty cell corpses was observed, indicating that part of the cells might undergo vacuolar PCD (self-digestion of cellular content after vacuole collapse). The wounding-induced local cell death at the primary site of damage suggested that PCD may serve as a mechanism to seal-off the wound by building a physical barrier of dead cells. However, the cell death at sites remote from the wound suggests the distribution of long-distance senescence-inducing wound messengers. Trichomes in unwounded tissue often were the first to show H2O2 accumulation and dead cells; thereafter, the elevated H2O2 and cell death appeared in connecting cells and senescence progressed over larger areas. This suggests that trichomes may contribute to mediating the wound signalling leading to subsequent senescence. Our findings demonstrate that PCD is an integral part of the wound syndrome in fresh-cut lettuce.

Symptoms of water stress are the most frequent cause for the “end of vase life” in prior stored roses. It was hypothesized that dark storage may alter the stomatal functionality and may cause water balance problems during the subsequent vase life period. The effect of short- and long-term storage on functionality of stomatal and subsequent flower performance was investigated in two rose cultivars (cvs) (‘Akito’ and ‘Grand Prix’) with presumed different sensitivity for development of water stress symptoms during the vase life. Compared to no storage, both short term storage (2.3 d at 6 °C) and long term storage (28 d at 0.5 °C) negatively affected the stomatal functionality in cultivar (cv) Akito. Stomatal functionality parameters such as the rapidity of the closing response upon dehydration and the relative water content at which stomata are fully closed showed good correlations with flower performance parameters (flower weight changes and vase life). This indicates that in cv Akito, the decreased stomatal functionality is one of the factors involved in the poor vase life of prior stored flowers. In cv Grand Prix, however, storage did not greatly affect the stomatal functionality but storage negatively affected flower performance in a comparable way as in cv Akito. A pre-treatment with abscisic acid prior to storage slightly improved stomatal functionality in both cvs, but no clear effect on flower performance was observed. Addition of the bactericide 8-HQC to the vase water improved flower performance in both cvs but could not alleviate the negative effect of cold storage on flower performance. Results show that in roses cold storage may, depending on the cultivar, negatively affect stomatal functionality and this may contribute to water stress and ultimately flower failure. In addition, cold storage may negatively affect xylem water conducting properties through processes not related to bacterial contamination.

Pot plant production in greenhouse is most of the time under high relative humidity and frequent irrigation, whereas during shipment and retailing plants may be exposed to high temperature and infrequent irrigation. These unfavorable conditions often cause water loss, desiccation of plants and short shelf life. To reduce the deteriorating effect of water loss, application of antitranspirants is one of the integral measures to take. In the first experiment, we evaluated the antitranspirant effect of two physiologically active gaseous compounds Ethylene and 1-MCP (1-methylcyclopropane) and their interaction with the successful active compound ABA (Abscisic acid). In the second experiment, with the aim of discovering a more potent antitranspirant, we evaluated the efficacy of an active compound-film forming blend. Excised leaves of Spathiphyllum sweet checo were sprayed with different preparations. Weight loss (transpiration) as gram of water per gram of initial leaf weight and stomatal conductance were measured. In the first experiment, 10 ppm Ethylene and 500 ppb 1-MCP found to reduce water loss conspicuously and negatively interacted with 1.5 mM ABA. In the second experiment, a potent mixture of active compound-film forming antitranspirants: ABA 1.5 mM + Leaf Shine 1:20 followed by SA (Salicylic acid) 5 mM + Leaf Shine 1:20 and SNP (Sodium nitroprusside) 200 µM + Leaf Shine 1:20 were discovered. In both experiments, significant positive correlations were found between weight loss and stomatal conductance (R= 0.975, 0.987, P

The production of volatile organic compounds (VOCs) during programmed cell death (PCD) is still insufficiently studied and their implication in the process is not well understood. The present study demonstrates that the release of VOSCs with presumed antioxidant capacity (methanethiol, dimethylsulfide and dimethyldisulfide) accompanies the cell death in chemical-stressed tobacco BY-2 suspension cultured cells. The cells were exposed to cell death inducers of biotic nature mastoparan (MP, wasp venom) and camptothecin (CPT, alkaloid), and to the abiotic stress agent CdSO4. The VOCs emission was monitored by proton-transfer reaction mass spectrometry (PTR-MS). The three chemicals induced PCD expressing apoptotic-like phenotype. The identified VOSCs were emitted in response to MP and CPT but not in presence of Cd. The VOSCs production occurred within few hours after the administration of the elicitors, peaked up when 20-50 % of the cells were dead and further levelled off with cell death advancement. This suggests that VOSCs with antioxidant activity may contribute to alleviation of cell death-associated oxidative stress at medium severity of cell death in response to the stress factors of biotic origin. The findings provide novel information about cell death defence mechanisms in chemical-challenged BY-2 cells and show that PCD related VOSCs synthesis depends on the type of inducer.

Visible and near infrared spectroscopy (VNIRS) (400−1000 nm) is a key emerging non-destructive technique for fruit quality assessment. This, because it is a unique method which allows rapid access to fruit pigments and chemical properties linked to fruit quality. In the present work, VNIRS has been used to predict the internal browning in ‘Keitt’ mangoes halves. The reference analysis was performed by cutting individual mango into halves and quantifying the extent of internal browning with a standardized color imaging (CI) cabinet as a browning index (BI). The CI provided a value for the “browning index” for each mango reflecting the presence and severity of internal browning. The data modelling involved both regression and classification analysis. The regression was performed to link the VNIR spectra with the BI values obtained from the internal color analysis. The classification analysis was performed for binary classification of mango into healthy or brown. Two different analysis techniques i.e. artificial neural network (ANN) and partial least square (PLS) were utilized. The study shows that VNIRS combined with ANN can classify mangoes as healthy or having internal brown with an accuracy of over 80 %. A robust and reliable classification system can potentially improve quality decisions through the mango supply chain, thereby reducing post-harvest losses.

We investigated the role of far-red LED light during cultivation on postharvest cold tolerance in tomato fruit (Solanum lycopersicum cv Moneymaker). Red and blue top LED light, providing 150 μmol m−2 s-1 photo-synthetically active radiation (PAR) at plant height for 16 h daily, was combined with 0, 30 or 50 μmol m−2 s-1 (non-PAR) far-red LED light. Tomatoes were harvested at the mature green or red stage and subjected to cold storage for 0, 5, 10, and 15 d at 4 °C, followed by 20 d shelf-life at 20 °C. Mature green harvested tomatoes, cultivated with additional far-red light, showed reduced weight loss, less pitting, faster red colour development during shelf-life (when prior long cold stored), and less softening (when prior short or non-cold stored). FR lighting during cultivation likely protects the membrane integrity of MG tomatoes and thus allows uninterrupted lycopene synthesis. Red harvested tomatoes cultivated with additional far-red light were firmer at harvest, showed reduced weight loss and less decay during shelf-life. Less red colouration was observed for red harvested fruits at the start of shelf-life when fruits were prior cold stored, indicative of lycopene breakdown during cold storage. The improved cold tolerance of red harvested fruits grown under additional far-red light is likely due to higher firmness at the start of the shelf-life period with lycopene acting as antioxidant during cold storage. In conclusion, additional far-red light during cultivation improved postharvest cold tolerance for tomatoes harvested at both the green and red maturity stage, and might therefore be suitable to prolong the storage potential of tomato at sub-optimal temperatures.

In vase life studies, cut flower fresh weight is often recorded, but mass distribution is not. Here, we addressed the variation in mass distribution among the different cut flower organs, and assessed its role in water relations. In the first part of the study, excised leaves, flower, and stem were exposed to desiccation. Water loss (per fresh mass) of both flower and stem was low, relatively constant over time and comparable between the three studied cultivars. Instead, water loss (per fresh mass) of leaves was initially much higher, and decreased upon desiccation due to stomatal closure. Leaves had the greatest contribution to cut flower water loss, while this contribution was different among the tested cultivars. Similar findings were obtained following evaluation of the contribution of leaves, stem, and flower to cut flower transpirational water loss under conditions where water supply was not limiting. A strong correlation between the leaf weight loss in the desiccation experiment and the length of vase life was found. Low evaporative demand during vase life evaluation increased vase life, and alleviated vase life differences between cultivars. Instead, high evaporative demand during evaluation shortened vase life, and increased the noted differences in vase life between cultivars. In the second part of the study, fresh weight partitioning was assessed within and among cut rose cultivars. Among eight cultivars, same weight flowering stems may have over 11% difference in leaf weight. In conclusion, cultivar differences in transpirational water loss between cut flowers of the same weight may be attributed to variations in both stomatal characteristics and mass partitioning to the leaves.

International audience; In near-infrared (NIR) spectroscopy of fresh fruit often the external influences due to differences in physical, chemical and environmental conditions lead to model failure. Correction methods are required where standard samples are measured covering all different conditions and then remodeling is performed. However, in the realworld, it is often difficult to measure standard samples. To deal with this, two different approaches to correct for external influences without standard sample measurements i.e., dynamic orthogonalization projection (DOP) and domain adaption (DA), are presented, and for the first time are applied to NIR spectroscopy of fresh fruit. Four different case studies, chosen based on their importance and their frequency of occurrences in the NIR spectroscopy domain, were used for the demonstration. The first case was an adaption to maintain the predictive performance of a model when used on a spectra from a second similar instrument. The second case was the correction of the temperature effects due to sensor heating. The third and fourth cases were about maintaining the model performance for multi-season fruit quality prediction models for mangos and for apples. In all of the cases, the aim was to solve the challenges without resorting to new measurement of standards. The results showed that for all the cases, both DOP and DA improved model performances. Up to 31% increase in R 2 p, and 98% and 66% reduction in prediction bias and root mean squared error (RMSE) of prediction were noted, respectively. The main benefit of the DOP and DA techniques in NIR spectroscopy is the limited need for standard measurements, providing general-purpose tools to complement the NIR spectroscopy and make the models scalable, transferable, and reusable.

Mangoes (Mangifera indica L.) are tropical fruits, which are sourced worldwide to supply the consumer market in Europe. Often mangoes are transported over sea in refrigerated containers at 8–10 °C and in some cases under controlled atmosphere conditions. At arrival in European countries, a vast amount of fruit is ripened under specified conditions to deliver 'Ready to Eat' fruit to consumers. The latter is a challenge due to great variability in fruit maturity stage at arrival. There are currently no good methodologies to rapidly and nondestructively monitor and control the ripening process of mangoes. A major indicator of mango ripeness is fruit firmness. In the present study, a portable visible near-infrared (400–1130 nm) (VNIR) spectrometer was used to predict the firmness of individual mango undergoing ripening. Ripening of ‘Kent’ mango was for 10 days monitored at 20 °C and relative humidity (RH) of 85%. Every other day fruit firmness (measured with AWETA acoustic firmness analyzer) and NIR spectrum were determined on 2 opposite sides of the fruit. Interval partial-least square (iPLSR) regression was used for identifying the important wavelengths responsible for predicting firmness in mangoes. Results showed a change in the VNIR spectra with the change in firmness of mangoes. The model based on selected wavelengths performed significantly better compared to PLSR without pre-selecting wavelengths. iPLSR based regression provided a correlation of calibration and prediction as R2c = 0.75 and R2p = 0.75, and root means squared error of calibration and prediction as 6.02 Hz2g2/3 and 5.92 Hz2g2/3 respectively. The iPLSR model outperformed the standard PLSR model by over 12% in R2p and 14% reduction in prediction error. The predictions by the model provided an evolution of the firmness during the complete ripening experiment. Non-destructive access to mango firmness during ripening can assist in optimizing the process to better meet the market demand.

Postharvest 1-methylcyclopropene (1-MCP) applications are commercially used on ‘Conference’ pears to obtain an improved fruit quality after storage for up to 11 months. Treatment with 1-MCP may result in firmer and greener fruit at the end of storage. During subsequent shelf life, 1-MCP treated pears may show slower ripening, including a reduced rate of softening and a reduced production of aroma volatiles. The lower levels of aroma volatiles and consumer complaints of reduced flavour suggest that flavour is negatively affected by 1-MCP treatments, which has raised concern within in the Dutch fruit industry. In the present study, the effect of pre-storage 1-MCP treatment on post-storage ripening and flavour perception was studied. Untreated and 1-MCP-treated pears (325 nL L−1) were stored for 8 months at -0.8 °C under controlled atmosphere conditions of 3 kPa O2 and 0.6 kPa CO2 according to commercially used protocols. At day 7 and 9 of the subsequent shelf life at 10 °C, 1-MCP-treated fruit showed decreased yellowing and ethylene production, whereas firmness was similar to that of untreated fruit. The production of aroma volatiles was significantly reduced in 1-MCP-treated fruit; this was especially observed for different acetate esters, ethanol and butanol. Despite the reduction in aroma volatiles, a consumer panel could not distinguish (in a Tetrad test) between samples from untreated and 1-MCP-treated fruit with similar firmness. This indicates that the important aroma volatiles, although reduced in abundance, were still above threshold levels and did not affect overall flavour perception. We conclude that 1-MCP does not affect flavour when pears within equal firmness classes are compared.

Pot plant production in the greenhouse is most of the time under high relative humidity and frequent irrigation. While, during shipping and retailing plants may be exposed to high temperature and infrequent irrigation. These unfavorable conditions often cause water loss, desiccation of plants and short shelf life. So as to reduce the deteriorating effect of water loss, application of anti-transpirants is one of the integral options to implement. In this study, we evaluated several physiologically active stomata closing compounds. Spathiphyllum sweet checo and Calathea rufibarba were sprayed with different active compound formulations. Weight loss of leaves as gram of water per gram of initial leaf weight and gram of water per centimeter square leaf area and stomatal conductance were measured. On both plant species most physiologically active compound treatments reduce weight loss and stomatal conductance significantly. 1.5 mM Abscisic acid (ABA), 5 mM Salicylic acid (SA) and 200 µM Sodium nitroprusside (SNP) on Spathiphyllum sweet checo and 1.5 mM ABA ,200 µM SNP and 200 µM Pyrabactin on Calathea rufibarba were the three most effective active compound treatments. Significant positive correlation were found between weight loss and stomatal conductance in both plant species (R=0.888, P

L-ascorbate (AsA; Vitamin C) is an anti-and pro-oxidant phytochemical essential for the proper functioning of the human body. Field grown tomato fruit (Solanum lycopersicum) contain substantial amounts of AsA. When grown in the greenhouse, tomato fruit typically have low levels of AsA. Light is the major regulatory abiotic factor for AsA in plants. The introduction of light emitting diodes (LED) in horticulture provides the opportunity for improving quality of plant products. AsA levels of tomato fruit increase with additional light applied to the plant. In this work we examine the effects of irradiance on AsA levels of tomato fruit when light is applied to the fruit. Detached tomato fruit were treated with different irradiance levels provided by LEDs in a climate controlled environment. Tomato fruit treated with 263 μmol m-2 s-1 of white light for 13 days contained 32% more AsA than fruit kept at lower irradiances or in darkness. The light induced biosynthesis of AsA and the role of soluble carbohydrates in AsA regulation is discussed.

L-ascorbate (ASC) is essential for human health. Therefore, there is interest in increasing the ASC content of crops like tomato. High irradiance induces accumulation of ASC in green tomato fruits. The D-mannose/L-galactose biosynthetic pathway accounts for the most ASC in plants. The myo-inositol and galacturonate pathways have been proposed to exist but never identified in plants. The D-mannose/L-galactose starts from D-glucose. In a series of experiments, we tested the hypothesis that ASC levels depend on soluble carbohydrate content when tomato fruits ripen under irradiances that stimulate ASC biosynthesis. We show that ASC levels considerably increased when fruits ripened under light, but carbohydrate levels did not show a parallel increase. When carbohydrate levels in fruits were altered by flower pruning, no effects on ASC levels were observed at harvest or after ripening under irradiances that induce ASC accumulation. Artificial feeding of trusses with sucrose increased carbohydrate levels, but did not affect the light-induced ASC levels. We conclude that light-induced accumulation of ASC is independent of the carbohydrate content in tomato fruits. In tomato fruit treated with light, the increase in ASC was preceded by a concomitant increase in myo-inositol.

Vertical farming is a technology that controls climate, water, nutrients and light to grow food in a closed environment. This allows vegetables to grow pesticide free and without other contaminants. We investigated how to influence the postharvest quality by controlling the preharvest growth conditions while keeping a high production rate. Several standard LED lighting recipes (red/blue or red/white either with or without far red) are in use in commercial farms. For this research we used lettuce, baby leaf spinach, rocket and basil from various cultivars all grown in a vertical farm research facility. We used the standard red white LED light recipe as control, while we changed the spectrum with higher blue and/or higher far-red or apply few days of continuous light stimulation just before the harvest (preharvest). Quality at harvest and quality loss during postharvest storage was monitored. We observed that light quality affects shelf life of baby leaf spinach and rocket by several days. The best light recipe for shelf life had a high blue content (35%) while the worst was with a high far red (25%). In addition, contents of vitamin C, K, nitrate, chlorophyll and flavonols were different under various light quality. Nitrate (in lettuce, rocket and spinach) and vitamin C in rocket were strongly affected by preharvest continuous light, offering a way to reduce the nitrate and improve the antioxidant level. In addition, taste was also found to change as a function of light quality but magnitude of this change is shown to be strongly cultivar dependent.