Chemical and Electrophysiological Characterisation of Headspace Volatiles from Yeasts Attractive to Drosophila suzukii.

Chemical control of Drosophila suzukii (Diptera: Drosophilidae) based on the use of insecticides is particularly challenging as the insect attacks ripening fruits shortly before harvest. An alternative strategy may rely on the use of yeasts as phagostimulants and baits, applied on canopy as attract-and-kill formulations. The aim of this research was to identify the most attractive among six yeast species for D. suzukii: Saccharomyces cerevisiae, Hanseniaspora uvarum, Clavispora santaluciae, Saccharomycopsis vini, Issatchenkia terricola, and Metschnikowia pulcherrima. The volatile profile of C. santaluciae was described for the first time. Behavioural experiments identified H. uvarum and S. vini as the most attractive yeasts. The characterization of yeast headspace volatiles using direct headspace (DHS) and solid-phase microextraction (SPME) revealed several strain-specific compounds. With DHS injection, 19 volatiles were characterised, while SPME revealed 71 compounds constituting the yeast headspace. Both analyses revealed terpenoids including ß-ocimene, citronellol, (Z)-geraniol (nerol), and geranial as distinct constituents of S. vini. H. uvarum and S. vini were further investigated using closed-loop stripping analysis (CSLA) and electroantennography. Out of 14 compounds quantified by CSLA, ethyl acetate, isoamyl acetate, ß-myrcene, benzaldehyde and linalool were detected by D. suzukii antennae and might generate the strong attractiveness of S. vini and H. uvarum. Our results highlight a strong attraction of D. suzukii to various yeasts associated with both the flies and their habitat and demonstrate how different sampling methods can impact the results of volatile compound characterization. It remains to be demonstrated whether the distinct attraction is based on special adaptations to certain yeasts and to what extent the metabolites causing attraction are interchangeable.

Establishing authenticity of hay milk: Detection of silage feeding through cyclopropane fatty acids analysis using 1H NMR spectroscopy.

Cyclopropane fatty acids (CPFAs) serve as indicators of silage feeding, verifying the authenticity of hay milk where silage feeding is forbidden. In this study, the authenticity of hay milk was determined by detecting CPFAs using proton nuclear magnetic resonance (1H NMR) spectroscopy. 245 milk samples were collected in South Tyrol (Italy), categorized as follows: 98 from grass silage-fed cows, 98 from maize silage-fed cows, and 49 authentic hay milk. The limit of detection of CPFAs was 12 µM, corresponding to 70 mg/kg of freeze-dried milk. The CPFAs were absent in all of the hay milk samples, verifying their authenticity. In contrast, 97 % of maize silage and 77 % of grass silage samples exhibited distinct CPFAs signals. These findings were further corroborated by gas chromatography-mass detector (GC-MS) analysis. The study highlights 1H NMR as a robust, and rapid technique for hay milk authentication, supporting alpine dairy production and increasing consumer trust in food authenticity.

Improved Detection and Quantification of Cyclopropane Fatty Acids via Homonuclear Decoupling Double Irradiation NMR Methods.

Over the years, NMR spectroscopy has become a powerful analytical tool for the identification and quantification of a variety of natural compounds in a broad range of food matrices. Furthermore, NMR can be useful for characterizing food matrices in terms of quality and authenticity, also allowing for the identification of counterfeits. Although NMR requires minimal sample preparation, this technique suffers from low intrinsic sensitivity relative to complementary techniques; thus, the detection of adulterants or markers for authenticity at low concentrations remains challenging. Here, we present a strategy to overcome this limitation by the introduction of a simple band-selective homonuclear decoupling sequence that consists of double irradiation on 1H during NMR signal acquisition. The utility of the proposed method is tested on dihydrosterculic acid (DHSA), one of the cyclopropane fatty acids (CPFAs) shown to be a powerful molecular marker for authentication of milk products. A quantitative description of how the proposed NMR scheme allows sensitivity enhancement yet accurate quantification of DHSA is provided.

Applications of Solution NMR Spectroscopy in Quality Assessment and Authentication of Bovine Milk.

Nuclear magnetic resonance (NMR) spectroscopy is emerging as a promising technique for the analysis of bovine milk, primarily due to its non-destructive nature, minimal sample preparation requirements, and comprehensive approach to untargeted milk analysis. These inherent strengths of NMR make it a formidable complementary tool to mass spectrometry-based techniques in milk metabolomic studies. This review aims to provide a comprehensive overview of the applications of NMR techniques in the quality assessment and authentication of bovine milk. It will focus on the experimental setup and data processing techniques that contribute to achieving accurate and highly reproducible results. The review will also highlight key studies that have utilized commonly used NMR methodologies in milk analysis, covering a wide range of application fields. These applications include determining milk animal species and feeding regimes, as well as assessing milk nutritional quality and authenticity. By providing an overview of the diverse applications of NMR in milk analysis, this review aims to demonstrate the versatility and significance of NMR spectroscopy as an invaluable tool for milk and dairy metabolomics research and hence, for assessing the quality and authenticity of bovine milk.

LC-Q-TOF-MS/MS data of phyllobilins in apple peels cv. 'Gala' during ripening under shelf-life conditions.

During senescence and ripening, higher plants degrade the green pigment chlorophyll to linear tetrapyrrols, referred to as phyllobilins (PBs). This dataset provides chromatograms and mass spectral data of PBs acquired from methanolic extracts of cv. Gala apple peels at five different shelf life (SL) stages. Data were obtained using a (ultra-high) pressure liquid chromatograph (UHPLC) coupled to high resolution quadrupole-time of flight-mass spectrometer (HRMS-Q-TOF). A data-dependent inclusion list (IL) ex professo containing all known masses of PBs was applied to address PBs, and fragmentation patterns were studied to confirm their identity operating a MS2 method. Mass accuracy was set to 5 ppm for parent ion peaks, this parameter was adopted as inclusion criterium. The detection of PBs' appearance during ripening can be helpful for assessing the quality and maturity of the apples.

Semi-Targeted Profiling of the Lipidome Changes Induced by Erysiphe Necator in Disease-Resistant and Vitis vinifera L. Varieties.

The ascomycete Erysiphe necator is a serious pathogen in viticulture. Despite the fact that some grapevine genotypes exhibit mono-locus or pyramided resistance to this fungus, the lipidomics basis of these genotypes' defense mechanisms remains unknown. Lipid molecules have critical functions in plant defenses, acting as structural barriers in the cell wall that limit pathogen access or as signaling molecules after stress responses that may regulate innate plant immunity. To unravel and better understand their involvement in plant defense, we used a novel approach of ultra-high performance liquid chromatography (UHPLC)-MS/MS to study how E. necator infection changes the lipid profile of genotypes with different sources of resistance, including BC4 (Run1), "Kishmish vatkhana" (Ren1), F26P92 (Ren3; Ren9), and "Teroldego" (a susceptible genotype), at 0, 24, and 48 hpi. The lipidome alterations were most visible at 24 hpi for BC4 and F26P92, and at 48 hpi for "Kishmish vatkhana". Among the most abundant lipids in grapevine leaves were the extra-plastidial lipids: glycerophosphocholine (PCs), glycerophosphoethanolamine (PEs) and the signaling lipids: glycerophosphates (Pas) and glycerophosphoinositols (PIs), followed by the plastid lipids: glycerophosphoglycerols (PGs), monogalactosyldiacylglycerols (MGDGs), and digalactosyldiacylglycerols (DGDGs) and, in lower amounts lyso-glycerophosphocholines (LPCs), lyso-glycerophosphoglycerols (LPGs), lyso-glycerophosphoinositols (LPIs), and lyso-glycerophosphoethanolamine (LPEs). Furthermore, the three resistant genotypes had the most prevalent down-accumulated lipid classes, while the susceptible genotype had the most prevalent up-accumulated lipid classes.

Secondary and primary metabolites reveal putative resistance-associated biomarkers against Erysiphe necator in resistant grapevine genotypes.

Numerous fungicide applications are required to control Erysiphe necator, the causative agent of powdery mildew. This increased demand for cultivars with strong and long-lasting field resistance to diseases and pests. In comparison to the susceptible cultivar 'Teroldego', the current study provides information on some promising disease-resistant varieties (mono-locus) carrying one E. necator-resistant locus: BC4 and 'Kishmish vatkana', as well as resistant genotypes carrying several E. necator resistant loci (pyramided): 'Bianca', F26P92, F13P71, and NY42. A clear picture of the metabolites' alterations in response to the pathogen is shown by profiling the main and secondary metabolism: primary compounds and lipids; volatile organic compounds and phenolic compounds at 0, 12, and 48 hours after pathogen inoculation. We identified several compounds whose metabolic modulation indicated that resistant plants initiate defense upon pathogen inoculation, which, while similar to the susceptible genotype in some cases, did not imply that the plants were not resistant, but rather that their resistance was modulated at different percentages of metabolite accumulation and with different effect sizes. As a result, we discovered ten up-accumulated metabolites that distinguished resistant from susceptible varieties in response to powdery mildew inoculation, three of which have already been proposed as resistance biomarkers due to their role in activating the plant defense response.

Geographic tracing of cereals from South Tyrol (Italy) and neighboring regions via 87Sr/86Sr isotope analysis.

The protection and promotion of agricultural niche products can be supported by the application of analytical techniques able to link food to its territory. This study aimed at exploring the possibility to discriminate between cereal samples from South Tyrol (Italy) and the neighboring regions (Trentino, East Tyrol, and North Tyrol) by their 87Sr/86Sr ratios. Soil and grain (different species) samples were collected from around 100 fields in two sampling campaigns. No difference in the 87Sr/86Sr ratios among different cereal species (p < 0.05) was found when cultivated on the same field. A high correlation between 87Sr/86Sr ratios in cereal grains and soil samples was found, with results in line with the local geology characteristics. Cereal samples from South Tyrol showed relatively high 87Sr/86Sr values (0.716 - 0.721, mean 50%), separating them from the other regions investigated and many cereal production areas of global importance.

Chlorophyll breakdown during fruit ripening: Qualitative analysis of phyllobilins in the peel of apples (Malus domestica Borkh.) cv. 'Gala' during different shelf life stages.

Chlorophyll (Chl) degradation is an important process of fruit ripening, mediated by the pheophorbide a oxygenase/phyllobilin (PaO/PB) pathway. Chl is catabolized to linear tetrapyrrolic phyllobilins that resemble the bile pigments. Determining the optimal harvest date is of pivotal importance for the fruit industry. Among the physiological changes at the onset of ripening and during shelf life, the breakdown of Chl appears as a promising indicator for fruit maturity. In addition, PBs are a frequently overlooked component of the human diet with antioxidant and antiproliferative activities. However, their relevance for a healthy diet and their potential as ripening indicator in fruit cannot be evaluated yet, as details on emergence and composition of PBs in fruit are yet elusive. Using apple (Malus × domestica Borkh.) cv. 'Gala' as a model fruit, the Chl content and the emergence and identity of PBs were analyzed during a controlled shelf life period using UV/Vis spectroscopy and ultra-high pressure liquid chromatography coupled to high resolution quadrupole-time of flight-mass spectrometry (UHPLC-Q-TOF-MS). An in-house database with chromatographic and MS data from 51 PBs, revealed ten chlorophyll catabolites, including five NCCs, one YCC, and four DNCCs (including a previously unknown one). PBs were identified with increasing abundance and diversity from the onset of Chl degradation, suggesting a potential role as ripening indicators.

Non-destructive fluorescence sensing for assessing microclimate, site and defoliation effects on flavonol dynamics and sugar prediction in Pinot blanc grapes.

In an era of growing international competition in modern viticulture, the study and implementation of innovative technologies to increase the production of high-quality grapes and wines are of critical importance. In this study, the non-destructive portable sensor Multiplex, based on fluorescence sensing technique, was applied to evaluate grape maturity parameters and flavonol content of the understudied Pinot blanc variety. The effects of environmental and agronomical factors on flavonol content of Pinot blanc grapes were investigated in eight vineyards characterised by different microclimatic and agronomic conditions. Furthermore, the direct impact of canopy management treatment on the flavonol dynamics of the grapes oriented in the four cardinal directions was assessed. Results highlight the positive role of moderate temperatures and direct sunlight exposure on Pinot blanc flavonol content; however, no direct vineyard-elevation effect was observed. The ability to modulate and evaluate the flavonol content in field represent crucial factors because of their potential effect on flavonoids-dependent wine characteristics, such as stability and ageing. In the present study, for the first time, two calibration curves were reported for pre- and post-veraison periods between flavonol indices and the berry skin flavonol content and a good correlation was observed between Multiplex measurement and the total polyphenolic content of grape juice. Moreover, the strong correlation between the chlorophyll index with grape juice sugar content and titratable acidity revealed the practical application of non-destructive sensors to predict the optimal harvest time for Pinot blanc grapes. In conclusion, the non-destructive fluorescence sensor Multiplex is a high-potential tool for innovative viticulture, for evaluating grape skin composition variables in white grape varieties.

Metabolomic Characterization of Pigmented and Non-Pigmented Potato Cultivars Using a Joint and Individual Variation Explained (JIVE).

Potatoes (Solanum tuberosum L.) are one of the most valuable agricultural crops, and the flesh of these tubers provides various classes of healthy compounds important for human nutrition. This work presents the results of a joint analysis of different chemical classes of compounds which provided insights on the metabolic characterization of pigmented and non-pigmented potato varieties collected from Italy. The identification of common or individual metabolic characteristics across the omic datasets (antioxidants, total polyphenolic content, polyphenols, and sugars) is conducted by Joint and Individual Variation Explained (JIVE), a data fusion multivariate approach. The common part of the multivariate model allowed the separation between non-pigmented and pigmented samples. Polyphenolic compounds were mainly responsible for the separation between purple-fleshed and red-skinned potatoes. An additional detailed analysis of the anthocyanin composition, including the acylated anthocyanins, allowed to pinpoint the diversities between the pigmented potato groups. Furthermore, the presence of an appreciable amount of hydroxycinnamic acids and anthocyanins in the purple-fleshed varieties, which are also characterized by a lower content of sugars, is found. Our results provide scientific evidence for the promotion of promising potato cultivars, which are characterized by a remarkable amount of various health benefit compounds.

Field and greenhouse application of an attract-and-kill formulation based on the yeast Hanseniaspora uvarum and the insecticide spinosad to control Drosophila suzukii in grapes.

BACKGROUND: The invasive insect Drosophila suzukii (Matsumura) is an important pest of several red grape varieties. The yeast Hanseniaspora uvarum (Niehaus), which is associated with D. suzukii, strongly attracts flies and stimulates them to feed on yeast-laden food. In the present study, a formulation based on H. uvarum culture with spinosad insecticide was applied to the foliage of vineyards and control of D. suzukii was compared to applying spinosad to the whole plant. After successful H. uvarum and insecticide application in the vineyard, we tested additional H. uvarum-based formulations with spinosad in a greenhouse to determine their capacity to control D. suzukii. RESULTS: Application of the H. uvarum-spinosad formulation at 36.4 g of spinosad per hectare reduced the D. suzukii field infestation at the same rate as applying 120 g of spinosad per hectare and prevented spinosad residues on grapes. Leaves treated with H. uvarum and spinosad in the field and transferred to a laboratory assay caused high mortality to flies and reduced the number of eggs laid on fruits. Formulations with spinosad applied in the greenhouse showed that both H. uvarum culture and the yeast cell-free supernatant of a centrifuged culture increased fly mortality and reduced the number of eggs laid compared to the unsprayed control. CONCLUSION: In comparison to typical spinosad spray applications, the use of H. uvarum in combination with spinosad as an attract-and-kill formulation against D. suzukii reduces pesticide residues on the fruits by targeting the treatment to the canopy and decreasing the amount of insecticide per hectare without compromising control efficacy.

Biogenic volatile organic compounds in the grapevine response to pathogens, beneficial microorganisms, resistance inducers, and abiotic factors.

The synthesis of volatile organic compounds (VOCs) in plants is triggered in response to external stimuli, and these compounds can migrate to distal tissues and neighbouring receivers. Although grapevine VOCs responsible for wine aroma and plant-insect communications are well characterized, functional properties of VOCs produced in response to phytopathogens, beneficial microorganisms, resistance inducers, and abiotic factors have been less studied. In this review, we focused on the emission patterns and potential biological functions of VOCs produced by grapevines in response to stimuli. Specific grapevine VOCs are emitted in response to the exogenous stimulus, suggesting their precise involvement in plant defence response. VOCs with inhibitory activities against pathogens and responsible for plant resistance induction are reported, and some of them can also be used as biomarkers of grapevine resistance. Likewise, VOCs produced in response to beneficial microorganisms and environmental factors are possible mediators of grapevine-microbe communications and abiotic stress tolerance. Although further functional studies may improve our knowledge, the existing literature suggests that VOCs have an underestimated potential application as pathogen inhibitors, resistance inducers against biotic or abiotic stresses, signalling molecules, membrane stabilizers, and modulators of reactive oxygen species. VOC patterns could also be used to screen for resistant traits or to monitor the plant physiological status.

Authenticity of Hay Milk vs. Milk from Maize or Grass Silage by Lipid Analysis.

Hay milk is a traditional dairy product recently launched on the market. It is protected as "traditional specialty guaranteed" (TSG) and subjected to strict regulations. One of the most important restrictions is that the cow's feed ration must be free from silage. There is the need for analytical methods that can discriminate milk obtained from a feeding regime including silage. This study proposes two analytical approaches to assess the authenticity of hay milk. Hay milk and milk from cows fed either with maize or grass silage were analyzed by targeted GC-MS for cyclopropane fatty acid (dihydrosterculic acid, DHSA) detection, since this fatty acid is strictly related to the bacterial strains found in silage, and by HPLC-HRMS. The presence of DHSA was correlated to the presence of maize silage in the feed, whereas it was ambiguous with grass silage. HPLC-HRMS analysis resulted in the identification of 14 triacylglycerol biomarkers in milk. With the use of these biomarkers and multivariate statistical analysis, we were able to predict the use of maize and grass silage in the cow's diet with 100% recognition. Our findings suggest that the use of analytical approaches based on HRMS is a viable authentication method for hay milk.

(3ξ,4ξ,5ξ,6ξ,7ξ,11ξ)-3,6-Dihydroxy-8-oxo-9-eremophilene-12-oic Acid, a New Phytotoxin of Alternaria alternata ssp. tenuissima Isolates Associated with Fruit Spots on Apple (Malus × domestica Borkh.).

Alternaria sp. infections on apple (Malus × domestica Borkh.) lead to impaired fruit quality and yield losses by leaf blotches and fruit spots, caused by host-specific toxins (HSTs) of the Alternaria apple pathotype like AM-toxins. Fungal isolates were obtained during severe outbreaks on cv. Gala, Golden Delicious, and Cripps Pink(cov)/Rosy Glow(cov) in South Tyrol and other regions in northern Italy. The isolates were tested for pathogenicity using in vitro assays with detached apple leaves. Conidial suspensions of pathogenic isolates were shown to provoke necrotic lesions also in apple seedlings and on fruits. Detached-leaf assay-guided fractionation of the isolates' culture supernatant and a high-resolution liquid chromatography-mass spectrometry (LC-MS) analysis tentatively identified 27 known Alternaria phytotoxins and a new putative toxin, (3ξ,4ξ,5ξ,6ξ,7ξ,11ξ)-3,6-dihydroxy-8-oxo-9-eremophilene-12-oic acid (1). The constitution and the relative configuration of the ring stereocenters of 1 were elucidated by NMR spectroscopy, revealing unique structural features among Alternaria phytotoxins. Indeed, molecular analysis revealed the lack of the toxin-related genes AMT1, AMT4, and AMT14 in all isolates from the region, suggesting that Alternaria apple blotch in the area was associated with another metabolite (1).

Chemosensory Profile of South Tyrolean Pinot Blanc Wines: A Multivariate Regression Approach.

A multivariate regression approach based on sensory data and chemical compositions has been applied to study the correlation between the sensory and chemical properties of Pinot Blanc wines from South Tyrol. The sensory properties were identified by descriptive analysis and the chemical profile was obtained by HS-SPME-GC/MS and HPLC. The profiles of the most influencing (positively or negatively) chemical components have been presented for each sensory descriptor. Partial Least Square Regression (PLS) and Principal Component Regression (PCR) models have been tested and applied. Visual (clarity, yellow colour), gustatory (sweetness, sourness, saltiness, bitterness, astringency, and warmness) and olfactory (overall intensity, floral, apple, pear, tropical fruit, dried fruit, fresh vegetative, spicy, cleanness, and off-odours) descriptors have been correlated with the volatile and phenolic profiles, respectively. Each olfactory descriptor was correlated via a PCR model to the volatile compounds, whereas a comprehensive PLS2 regression model was built for the correlation between visual/gustatory descriptors and the phenolic fingerprint. "Apple" was the olfactory descriptor best modelled by PCR, with an adjusted R2 of 0.72, with only 20% of the validation samples falling out of the confidence interval (α = 95%). A PLS2 with 6 factors was chosen as the best model for gustatory and visual descriptors related to the phenolic compounds. Finally, the overall quality judgment could be explained by a combination of the calibrated sensory descriptors through a PLS model. This allowed the identification of sensory descriptors such as "olfactory intensity", "warmness", "apple", "saltiness", "astringency", "cleanness", "clarity" and "pear", which relevantly contributed to the overall quality of Pinot Blanc wines from South Tyrol, obtained with two different winemaking processes and aged in bottle for 18 months.

Mono-Locus and Pyramided Resistant Grapevine Cultivars Reveal Early Putative Biomarkers Upon Artificial Inoculation With Plasmopara viticola.

One of the most economically important grapevine diseases is Downy mildew (DM) caused by the oomycete Plasmopara viticola. A strategy to reduce the use of fungicides to compensate for the high susceptibility of V. vinifera is the selection of grapevine varieties showing pathogen-specific resistance. We applied a metabolomics approach to evaluate the metabolic modulation in mono-locus resistant genotypes carrying one locus associated with P. viticola resistance (Rpv) (BC4- Rpv1, Bianca- Rpv3-1, F12P160- Rpv12, Solaris- Rpv10), as well as in pyramided resistant genotypes carrying more than one Rpv (F12P60- Rpv3-1; Rpv12 and F12P127- Rpv3-1, Rpv3-3; Rpv10) taking as a reference the susceptible genotype Pinot Noir. In order to understand if different sources of resistance are associated with different degrees of resistance and, implicitly, with different responses to the pathogen, we considered the most important classes of plant metabolite primary compounds, lipids, phenols and volatile organic compounds at 0, 12, 48, and 96 h post-artificial inoculation (hpi). We identified 264 modulated compounds; among these, 22 metabolites were found accumulated in significant quantities in the resistant cultivars compared to Pinot Noir. In mono-locus genotypes, the highest modulation of the metabolites was noticed at 48 and 96 hpi, except for Solaris, that showed a behavior similar to the pyramided genotypes in which the changes started to occur as early as 12 hpi. Bianca, Solaris and F12P60 showed the highest number of interesting compounds accumulated after the artificial infection and with a putative effect against the pathogen. In contrast, Pinot Noir showed a less effective defense response in containing DM growth.

Detection of apple proliferation disease in Malus × domestica by near infrared reflectance analysis of leaves.

In this study near infrared spectroscopical analysis of dried and ground leaves was performed and combined with a multivariate data analysis to distinguish 'Candidatus Phytoplasma mali' infected from non-infected apple trees (Malus × domestica). The bacterium is the causative agent of Apple Proliferation, one of the most threatening diseases in commercial apple growing regions. In a two-year study, leaves were sampled from three apple orchards, at different sampling events throughout the vegetation period. The spectral data were analyzed with a principal component analysis and classification models were developed. The model performance for the differentiation of Apple Proliferation diseased from non-infected trees increased throughout the vegetation period and gained best results in autumn. Even with asymptomatic leaves from infected trees a correct classification was possible indicating that the spectral-based method provides reliable results even if samples without visible symptoms are analyzed. The wavelength regions that contributed to the differentiation of infected and non-infected trees could be mainly assigned to a reduction of carbohydrates and N-containing organic compounds. Wet chemical analyses confirmed that N-containing compounds are reduced in leaves from infected trees. The results of our study provide a valuable indication that spectral analysis is a promising technique for Apple Proliferation detection in future smart farming approaches.

Metabolomic Characterization of Commercial, Old, and Red-Fleshed Apple Varieties.

In this study, a metabolomic investigation was presented to correlate single polyphenolic compounds in apple pulp with quality characteristics such as antioxidant activity and content of phenolic compounds and anthocyanins in apple skin. Since the concentration of these compounds is influenced by environmental factors, the twenty-two apple cultivars originate from the same site. The polyphenolic compounds were analyzed by ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS). The antioxidant activity, phenolic content, and anthocyanins were evaluated on the sunny and the shady sides of apple skin by spectrometric assays. In old apple varieties, the measured parameters were higher than in the commercial and red-fleshed varieties. By contrast, the profile of flavan-3-ols and anthocyanins was variable amongst commercial and red-fleshed varieties. The partial least square (PLS) method was applied to investigate the association between the skin proprieties and the metabolic profile of the pulp. The highest coefficients of determination in prediction (Q2) were obtained for compounds quantified in old cultivars. These results provided information to define the old apple varieties as a reliable group based on the pathway of the antioxidant compounds and anthocyanins content. Our results show the possibility to find cultivars with promising health features based on their content of polyphenols suitable for commercialization or breeding.

Multi-chemical analysis combined with chemometrics to characterize PDO and PGI Italian apples.

BACKGROUND: The use of PDO (protected designation of origin) and PGI (protected geographical indication) labels allows to protect and promote agricultural products characterized by unique features related to the place of origin and traditional know-how. However, the presence of non-authentic products in the market represents a fraud that can be tackled applying analytical techniques combined with chemometric analysis. In this study, we applied multi-element and multi-isotope analysis to characterize PDO and PGI apples cultivated in northern Italy, comparing them with Italian apples without labels of geographical indications. RESULTS: The multi-element and multi-isotope approach allowed to characterize the apples cultivated in northern Italy. Despite a significant effect of the sampling sites on the apple composition, the comparison of the multi-chemical fingerprint of the apples significantly varied among cultivation areas. Results of this characterization were used to classify samples according to their cultivation area applying a linear discriminant analysis (LDA). Outputs of the LDA showed that correct sample classification can be successfully achieved (balanced accuracy > 96%). Moreover, using a selection of variables, it was possible to correctly classify samples also at regional level. CONCLUSION: The presented evidences indicate that the multi-element and multi-isotope fingerprint can be successfully applied to traceability studies. The combination of this characterization with chemometric tools allows the classification of Italian apples based on their origin both on a national and regional scale. This approach represents an interesting tool to enhance and protect PDO and PGI Italian products. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.