Volatile metabolites, quality and sensory parameters of “Ferrovia” sweet cherry cold stored in air or packed in high CO2 modified atmospheres

Agronomic, Physicochemical, Aromatic and Sensory Characterization of Four Sweet Cherry Accessions of the Campania Region

Sweet cherries (Prunus avium L.) are greatly appreciated fruits worldwide due to their taste, color, nutritional value, and beneficial health effects. The characterization of autochthonous germplasm allows to identify genotypes that possess superior characteristics compared to standard cultivars. In this work, four accessions of sweet cherry from the Campania region (Limoncella, Mulegnana Riccia, Mulegnana Nera and Montenero) were investigated for their morpho-physiological, qualitative, aromatic, and sensorial traits in comparison with two standard cultivars (Ferrovia and Lapins). A high variability in the pomological traits resulted among the samples. Montenero showed comparable fruit weight and titratable acidity to Ferrovia and Lapins, respectively. The highest total soluble solid content was detected in Mulegnana Riccia. A considerable variability in the skin and pulp color of the cherries was observed, varying from yellow-red in Limoncella to a dark red color in Montenero. Mulegnana Nera showed the highest content of polyphenols, flavonoids, anthocyanins, and ascorbic acid compared to the standard cultivars. Volatile organic compounds profile analysis identified 34 volatile compounds, 12 of which were observed at different concentrations in all the sweet cherry genotypes while the others were genotype-dependent. Conservation and cultivation of autochthonous accessions with suitable nutritional and morpho-physiologic characteristics promotes our agrobiodiversity knowledge and allows to better plan future breeding programs.

Emerging Postharvest Technologies to Enhance the Shelf-Life of Fruit and Vegetables: An Overview

Quality losses in fresh produce throughout the postharvest phase are often due to the inappropriate use of preservation technologies. In the last few decades, besides the traditional approaches, advanced postharvest physical and chemical treatments (active packaging, dipping, vacuum impregnation, conventional heating, pulsed electric field, high hydrostatic pressure, and cold plasma) and biocontrol techniques have been implemented to preserve the nutritional value and safety of fresh produce. The application of these methodologies after harvesting is useful when addressing quality loss due to the long duration when transporting products to distant markets. Among the emerging technologies and contactless and non-destructive techniques for quality monitoring (image analysis, electronic noses, and near-infrared spectroscopy) present numerous advantages over the traditional, destructive methods. The present review paper has grouped original studies within the topic of advanced postharvest technologies, to preserve quality and reduce losses and waste in fresh produce. Moreover, the effectiveness and advantages of some contactless and non-destructive methodologies for monitoring the quality of fruit and vegetables will also be discussed and compared to the traditional methods.

Opportunities in phytochemistry, ecophysiology and wood research via laser ablation direct analysis in real time imaging-mass spectrometry

Analysis of wood transects in a manner that preserves the spatial distribution of the metabolites present is highly desirable to among other things: (1) facilitate ecophysiology studies that reveal the association between chemical make-up and environmental factors or climatic events over time; and (2) investigate the mechanisms of the synthesis and trafficking of small molecules within specialised tissues. While a variety of techniques could be applied to achieve these goals, most remain challenging and impractical. Laser ablation direct analysis in real time imaging-mass spectrometry (LADI-MS) was successfully used to survey the chemical profile of wood, while also preserving the small-molecule spatial distributions. The tree species Entandrophragma candollei Harms, Millettia laurentii DeWild., Pericopsis elata (Harms) Meeuwen, Dalbergia nigra (Vell.) Benth. and Dalbergia normandii Bosser & R.Rabev were analysed. Several compounds were associated with anatomical features. A greater diversity was detected in the vessels and parenchyma compared with the fibres. Analysis of single vessels revealed that the chemical fingerprint used for timber identification is mainly determined by vessel content. Laser ablation direct analysis in real time imaging-mass spectrometry offers unprecedented opportunities to investigate the distribution of metabolites within wood samples, while circumventing the issues associated with previous methods. This technique opens up new vistas for the discovery of small-molecule biomarkers that are linked to environmental events.

Mineral Content and Volatile Profiling of Prunus avium L. (Sweet Cherry) By-Products from Fundão Region (Portugal)

Large amounts of Prunus avium L. by-products result from sweet cherry production and processing. This work aimed to evaluate the mineral content and volatile profiling of the cherry stems, leaves, and flowers of the Saco cultivar collected from the Fundão region (Portugal). A total of 18 minerals were determined by ICP-MS, namely 8 essential and 10 non-essential elements. Phosphorus (P) was the most abundant mineral, while lithium (Li) was detected in trace amounts. Three different preparations were used in this work to determine volatiles: hydroethanolic extracts, crude extracts, and aqueous infusions. A total of 117 volatile compounds were identified using HS-SPME/GC-MS, distributed among different chemical classes: 31 aldehydes, 14 alcohols, 16 ketones, 30 esters, 4 acids, 4 monoterpenes, 3 norisoprenoids, 4 hydrocarbons, 7 heterocyclics, 1 lactone, 1 phenol, and 2 phenylpropenes. Benzaldehyde, 4-methyl-benzaldehyde, hexanal, lilac aldehyde, and 6-methyl-5-hepten-2-one were the major volatile compounds. Differences in the types of volatiles and their respective amounts in the different extracts were found. This is the first study that describes the mineral and volatile composition of Portuguese sweet cherry by-products, demonstrating that they could have great potential as nutraceutical ingredients and natural flavoring agents to be used in the pharmaceutical, cosmetic, and food industries.

Melatonin Pre-harvest Treatments Leads to Maintenance of Sweet Cherry Quality During Storage by Increasing Antioxidant Systems

Melatonin has been reported to have an important role in fruit ripening, although the effect of pre-harvest melatonin treatment on sweet cherry quality properties during storage is still unknown. In the present experiments, the effects of melatonin (0.1, 0.3, and 0.5 Mm) by foliar spray treatments of 'Prime Giant' and 'Sweet Heart' sweet cherry trees on fruit quality traits and antioxidants systems during storage was evaluated. Results showed that these treatments reduced weight losses during storage, as well as losses in firmness and titratable acidity. In addition, changes in fruit colour and total soluble solid content were also delayed in fruit from melatonin treated trees with respect to controls. Moreover, in general, total phenolic and anthocyanin concentrations were higher in fruit from treated trees than in those from control ones, either at harvest or during the whole storage period. Finally, the activity of the antioxidant enzymes catalase, ascorbate peroxidase and peroxidase was also enhanced as a consequence of melatonin treatment. Overall results show that pre-harvest melatonin treatment delayed the post-harvest ripening process of sweet cherry fruit, leading to maintenance of their quality properties in optimum levels for consumption 2 weeks more with respect to fruit from control trees. Antioxidant systems, both enzymatic and non-enzymatic ones, were also enhanced by melatonin treatments, which would account for the delay on fruit post-harvest ripening process and fruit quality maintenance during storage.

Effect of Vacuum Impregnation with Sucrose and Plant Growth Hormones to Mitigate the Chilling Injury in Spinach Leaves

Vacuum impregnation (VI) has been immensely used in modifying the physicochemical properties, nutritional values and sensory attributes of fruits and vegetables. However, the metabolic consequences of the plant tissue upon impregnation have not been profoundly explored although shelf life is strongly dependent on this factor. In this study, spinach leaves were impregnated with salicylic acid (SA), γ-aminobutyric acid (GABA) and sucrose to improve its quality and storage ability by reducing the chilling injury through the improvement of proline content. The spinach leaves were stored at 4 °C for 7 days and were analyzed at 12 h interval. Upon 1 day of impregnation, the proline content in GABA, sucrose and SA impregnated leaves was increased by 240%, 153% and 103%, respectively, while in non-impregnated leaves, the proline content was decreased by 23.8%. The chlorophyll content of GABA impregnated leaves exhibited the lowest reduction (49%) followed by sucrose (55%) and SA (57%); meanwhile, non-impregnated leaves reduced 80% of chlorophyll content at the end of storage. Sensory evaluation showed that GABA, sucrose and SA impregnated leaves respectively, obtained higher score in terms of freshness, color, texture and overall appearance as compared to non-impregnated leaves.

Electronic-Nose as Non-destructive Tool to Discriminate "Ferrovia" Sweet Cherries Cold Stored in Air or Packed in High CO2 Modified Atmospheres

This study aimed to explore the applicability of electronic-nose (E-nose) as a rapid method in discriminating samples of sweet cherry cv “Ferrovia” stored in high-CO₂ (16% O₂ + 20% CO₂ + 64% N₂) or air (control) up to 21 days. Projection to Latent Structures (PLS) methods applied to E-nose data showed that fresh fruit and the packaged or unpackaged samples can be distinguished, according to both the storage condition and the storage days. Moreover, a correlation analysis between E-nose sensors and 45 volatile compounds were overall, obtained from all the investigated sweet cherry samples by Headspace Solid-Phase Microextraction (HS SPME) coupled to Gas Chromatography-Mass Spectrometry (GC-MS). These methods allowed to associate samples with a specific flavour profile to one or more E-nose sensors. Finally, quality attributes (visual quality, colour, firmness, antioxidant activity, total phenols, and sugar content) were assessed during storage. Among these, visual quality and berry deformation resulted affected by storage conditions, showing that high-CO₂ treatment better preserved the fruit quality than control.

Essential and non-essential elements, and volatile organic compounds for the discrimination of twenty-three sweet cherry cultivars from Fundão, Portugal

The mineral contents and volatile profiles of 23 sweet cherry cultivars were determined. A total of 27 minerals were determined by ICP-MS and flame atomic absorption spectrometry, including 12 essential and 15 non-essential elements. K was the most abundant in all cultivars, while Tl was the one found in the smallest amounts. A total of 66 volatiles were identified using SPME/GC-MS, including 16 aldehydes, 23 alcohols, 6 ketones, 6 esters, 8 monoterpenes, 3 norisoprenoids, 2 hydrocarbons and 2 acids. Benzaldehyde, hexanal, nonanal, benzyl alcohol, (E)-2-hexen-1-ol, 1-hexanol, (Z)-2-hexen-1-ol, 2-ethyl-1-hexanol, linalool, α-terpineol and α-ionone were the major ones. Qualitative and quantitative differences were observed among the cultivars, which influenced nutritional potential and aroma. Cherries from Fundão region contain high concentrations of phytochemicals and nutritional components. 4-84, Burlat and Celeste might be considered some of the most interesting cultivars, since they are rich in essential minerals and present high diversity in volatiles.

Effective pretreatment technologies for fresh foods aimed for use in central kitchen processing

The central kitchen concept is a new trend in the food industry, where centralized preparation and processing of fresh foods and the distribution of finished or semi-finished products to catering chains or related units take place. Fresh foods processed by a central kitchen mainly include fruit and vegetables, meat, aquatic products, and edible fungi; these foods have high water activities and thermal sensitivities and must be processed with care. Appropriate pretreatments are generally required for these food materials; typical pretreatment processes include cleaning, enzyme inactivation, and disinfection, as well as packaging and coating. To improve the working efficiency of a central kitchen, novel efficient pretreatment technologies are needed. This article systematically reviews various high-efficiency pretreatment technologies for fresh foods. These include ultrasonic cleaning technologies, physical-field enzyme inactivation technologies, non-thermal disinfection technologies, and modified-atmosphere packagings and coatings. Mechanisms, applications, influencing factors, and advantages and disadvantages of these technologies, which can be used in a central kitchen, are outlined and discussed. Possible solutions to problems related to central-kitchen food processing are addressed, including low cleaning efficiency and automation feasibility, high nutrition loss, high energy consumption, and short shelf life of products. These should lead us to the next step of fresh food processing for a highly demanding modern society. © 2020 Society of Chemical Industry.

Physical and phytochemical composition of 23 Portuguese sweet cherries as conditioned by variety (or genotype)

This study aimed to analyze physicochemical characteristics and phenolic profile of twenty-three sweet cherry cultivars from Fundão region, Portugal. The average length and width ranged between 1.9 and 2.6 and 2.1-2.8 cm, respectively. Weight varied between 4.9 and 11.8 g, firmness ranged from 7.3 to 20.1 N, moisture and ash contents ranged from 75.1 to 88.6% and 0.4 to 2.9%, respectively. Sunburst and Sweetheart presented high values of CIEL∗, a∗ and b∗, and low values regarding total soluble solids and maturity index. A total of 46 phenolic compounds were identified by HPLC-DAD-ESI/MSⁿ and quantified by HPLC-DAD, namely 19 hydroxycinnamic acids, 2 hydroxybenzoic acids, 13 flavonols, 5 flavan-3-ols, 2 flavanones, 1 flavanonol and 4 anthocyanins. Sunburst and Brook's were the richest in non-colored phenolics, while Garnet and Tavora were the richest ones in anthocyanins. Therefore, our results revealed that sweet cherries represent a supply of high-value bioactive compounds, being greatly influenced by the cultivar.

Multi-Sensors Enabled Dynamic Monitoring and Quality Assessment System (DMQAS) of Sweet Cherry in Express Logistics

The market demand for fresh sweet cherries in China has experienced continuous growth due to its rich nutritional value and unique taste. Nonetheless, the characteristics of fruits, transportation conditions and uneven distribution pose a huge obstacle in keeping high quality, especially in express logistics. This paper proposes dynamic monitoring and quality assessment system (DMQAS) to reduce the quality loss of sweet cherries in express logistics. The DMQAS was tested and evaluated in three typical express logistics scenarios with “Meizao” sweet cherries. The results showed that DMQAS could monitor the changes of critical micro-environmental parameters (temperature, relative humidity, O₂, CO₂ and C₂H₄) during the express logistics, and the freshness prediction model showed high accuracy (the relative error was controlled within 10%). The proposed DMQAS could provide complete and accurate microenvironment data and can be used to further improve the quality and safety management of sweet cherries during express logistics.

Nanomaterial Gas Sensors for Online Monitoring System of Fruit Jams

Jams are appreciated worldwide and have become a growing market, due to the greater attention paid by consumers for healthy food. The selected products for this study represent a segment of the European market that addresses natural products without added sucrose or with a low content of natural sugars. This study aims to identify volatile organic compounds (VOCs) that characterize three flavors of fruit and five recipes using gas chromatography-mass spectrometry (GC-MS) and solid-phase micro-extraction (SPME) analysis. Furthermore, an innovative device, a small sensor system (S3), based on gas sensors with nanomaterials has been used; it may be particularly advantageous in the production line. Results obtained with linear discriminant analysis (LDA) show that S3 can distinguish among the different recipes thanks to the differences in the VOCs that are present in the specimens, as evidenced by the GC-MS analysis. Finally, this study highlights how the thermal processes for obtaining the jam do not alter the natural properties of the fruit.

Impact of elevated O2 and CO2 atmospheres on chemical attributes and quality of strawberry (Fragaria × ananassa Duch.) during storage

Modified atmosphere has widely been evident to contribute to fruit quality maintenance, however the correlation among these quality traits was less known. To explore main factors of elevated atmosphere and reduce the detection indexes, we exposed strawberry to either high O₂ (80% O₂ + 20% N₂) or CO₂ (20% CO₂ + 20% O₂ + 60% N₂) atmosphere and compared quality characteristics. It was demonstrated that both atmospheres well maintained the fruit firmness, alleviated weight loss and decay rate. Elevated O₂ maintained the polyphenolic contents and cell integrity by significantly decreasing superoxide and hydrogen peroxide levels. PCA analysis implied that HO treatment mainly affected oxygen metabolism while HCO affected carbon metabolism more. Significantly positive correlation was observed between weight loss, anthocyanin content and decay rate in elevated O₂ and control groups. This study provided new insights into correlation and difference between impact of elevated O₂ and CO₂ to postharvest preservation.