•Accurate NIR calibration models were obtained for main quality indexes of apples.•Total phenolics and antioxidant activity of apples could be predicted by NIR-based models.•Classification models ...were able to discriminate apple lots on the basis of storage time.
Apples can be stored for long time under controlled temperature and atmosphere conditions, and therefore, non-destructive and rapid tools are required to assess fruit quality and to monitor changes during the postharvest period. The aim of this study was to evaluate the feasibility of NIR spectroscopy to optimize postharvest apple management and to follow changes in fruit quality during storage. An FT-NIR system operating in diffuse reflectance in the range 12,500–3600cm−1 was used to evaluate the physico-chemical (dry matter, soluble solids, colour and firmness) and some nutraceutical characteristics (total phenolics, total flavonoids and antioxidant activity) of ‘Golden Delicious’ apples, which were stored for about six months at 1°C in controlled atmosphere, over two subsequent years. Spectral data were elaborated by PLS regression and LDA classification techniques. Good correlation models between spectral data and chemical and physical parameters were obtained for soluble solids, a* colour coordinate and firmness (0.81<R2<0.90 in calibration and 0.79<R2<0.89 in cross validation). Even higher correlation values (0.89<R2<0.95 in calibration and 0.86<R2<0.92 in cross validation) were obtained for indexes correlated to the antioxidant capacity of apples. The classification technique Linear Discriminant Analysis was applied to spectral data, in order to discriminate apples on the basis of storage time. Average correct classification was higher than 93% in validation and close to 100% in calibration, indicating high potential of NIR spectroscopy for the estimation of storage time of apple lots.
The aims were: (1) to follow the freshness decay of minced beef stored in high-oxygen modified atmosphere packaging at different temperatures (4.3, 8.1 and 15.5
°C) by applying traditional methods ...(microbiological counts, color evaluation, thiobarbituric acid assay TBA, headspace gas composition) and e-nose; (2) to model the decay kinetics to obtain information about the maximum shelf life as function of storage conditions. The minced beef, packaged in modified atmosphere was supplied by a manufacturer at the beginning of its commercial life. The study demonstrated the ability of the traditional methods to describe the kinetics of freshness decay. The modeling of the experimental data and the comparison with microbiological or chemical thresholds allowed the setting, for each index, of a stability time above which the meat was no longer acceptable. The quality decay of meat was also evaluated by the headspace fingerprint of the same set of samples by means of a commercial e-nose. A clear discrimination between “fresh” and “old” samples was obtained using PCA and CA, determining at each temperature a specific range of stability time. The mean value of the stability times calculated for each index was 9
days at 4.3
°C (recommended storage temperature), 3–4
days at 8.1
°C (usual temperature in household refrigerators) and 2
days at 15.5
°C (abuse temperature). Resolution of the stability times allowed calculation of mean Q
10 values, i.e. the increase in rate for a 10
°C increase in temperature.
The results show that the
Q
10 values from the traditional methods (3.6–4.0 range) overlapped with those estimated with e-nose and color indexes (3.4 and 3.9, respectively).
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► Characterisation of the Italian PDO extra virgin olive oil
Chianti Classico. ► Comparison between non-selective (UV–vis, NIR and MIR spectroscopy) and selective (fatty acid ...composition) analytical techniques. ► Synergy among spectroscopic techniques, by the fusion of the respective spectra. ► Prediction of the content of oleic and linoleic acids in the olive oils.
An authentication study of the Italian PDO (protected designation of origin) extra virgin olive oil
Chianti Classico was performed; UV–visible (UV–vis), Near-Infrared (NIR) and Mid-Infrared (MIR) spectroscopies were applied to a set of samples representative of the whole
Chianti Classico production area.
The non-selective signals (fingerprints) provided by the three spectroscopic techniques were utilised both individually and jointly, after fusion of the respective profile vectors, in order to build a model for the
Chianti Classico PDO olive oil.
Moreover, these results were compared with those obtained by the gas chromatographic determination of the fatty acids composition.
In order to characterise the olive oils produced in the
Chianti Classico PDO area, UNEQ (unequal class models) and SIMCA (soft independent modelling of class analogy) were employed both on the MIR, NIR and UV–vis spectra, individually and jointly, and on the fatty acid composition.
Finally, PLS (partial least square) regression was applied on the UV–vis, NIR and MIR spectra, in order to predict the content of oleic and linoleic acids in the extra virgin olive oils.
UNEQ, SIMCA and PLS were performed after selection of the relevant predictors, in order to increase the efficiency of both classification and regression models.
The non-selective information obtained from UV–vis, NIR and MIR spectroscopy allowed to build reliable models for checking the authenticity of the Italian PDO extra virgin olive oil
Chianti Classico.
European sea bass (
Dicentrarchus labrax) is one of the finfish species preferred by the consumer, who requires fish freshness to be maintained during distribution and retail. For this reason, the ...purposes of this study were to define: the shelf life at three storage temperatures (−0.5, 4.8 and 16.5
°C) by applying both chemical (TVB and TBA assays) and olfactometric (e-nose) method; the actual time–temperature exposure conditions during marketing; the prediction of remaining shelf life in the commercial chain, on the basis of time–temperature history data and on appropriate integration routine. Shelf life study revealed the efficacy of chemical markers and electronic nose in describing the freshness decay and in defining a freshness threshold. Freshness of sea bass was kept for about 8 days for fish preserved in melting ice (−0.5
°C), 4 days at 4.8
°C and about 1 day at 16.5
°C. When fresh European sea bass was purchased, 9 out of 10 times the remaining shelf life was more than 55% at an average temperature of 1.19
°C. Therefore, the freshness of fish can be assured for 3–4 days in commercialization. A joint effort (sales point management and consumer advertising) could reduce the exposure temperature by 1–2
°C and justify an extension of the shelf life to 2–3 days after purchase.
The effect of a steam blanching preconditioning step was investigated on the chemical, nutraceutical and morphological characteristics of osmo-dehydrated blueberries (Vaccinium corymbosum L.) in ...sucrose or glucose/fructose osmotic solutions. Mass transfer phenomena (solid gain, water loss and sugar gain) were monitored into the samples at intervals over a 24-h period of osmodehydration. The antioxidant capacity of untreated and osmo-dehydrated fruits was evaluated by total phenolics, total and individual anthocyanins and antioxidant activity (amperometric method), while colorimetric (luminance) and morphological (area, shape factor, fractal dimension) characteristics of the berries were determined by image-analysis technique. Results showed that the blanching step increased mass transfer phenomena in the course of the osmodehydration treatments (approx +55% solid gain and +33% water loss) and reduced the loss of phenolic compounds, improving the retention of antioxidant capacity in the final product (from approx 66.9–56.9% in not blanched berries to 88.6–95.7% in blanched ones). Blanched berries had also deeper colour and smoother surface. Slight differences in mass balances and in the final composition of berries could be ascribed to the kind of osmotic solution used.
► Influence of steam-blanching pretreatment on the quality of osmodehydrated blueberries ► Mass transfer phenomena are enhanced by a steam blanching pretreatment ► Higher sugar gain is obtained in glucose/fructose and higher water loss in sucrose ► The loss of phenolic antioxidants is partially prevented by berry blanching ► Blanched osmo-dehydrated berries have deeper colour, higher turgidity and smoother surface
Application of non destructive methods for the monitoring of red wine fermentation in correlation with the evolution of chemical parameters.
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► We monitored time-related changes in red ...wine fermentation process. ► NIR and MIR spectroscopies, electronic nose and tongue were applied. ► Data were kinetically modelled to identify critical points during fermentation. ► NIR, MIR electronic nose and tongue were able to follow the fermentation process. ► The models agreed with the evolution of chemical parameters.
Effective fermentation monitoring is a growing need due to the rapid pace of change in the wine industry, which calls for fast methods providing real time information in order to assure the quality of the final product. The objective of this work is to investigate the potential of non-destructive techniques associated with chemometric data analysis, to monitor time-related changes that occur during red wine fermentation. Eight micro-fermentation trials conducted in the Valtellina region (Northern Italy) during the 2009 vintage, were monitored by a FT-NIR and a FT-IR spectrometer and by an electronic nose and tongue. The spectroscopic technique was used to investigate molecular changes, while electronic nose and electronic tongue evaluated the evolution of the aroma and taste profile during the must-wine fermentation. Must-wine samples were also analysed by traditional chemical methods in order to determine sugars (glucose and fructose) consumption and alcohol (ethanol and glycerol) production. Principal Component Analysis was applied to spectral, electronic nose and electronic tongue data, as an exploratory tool, to uncover molecular, aroma and taste modifications during the fermentation process. Furthermore, the chemical data and the PC1 scores from spectral, electronic nose and electronic tongue data were modelled as a function of time to identify critical points during fermentation. The results showed that NIR and MIR spectroscopies are useful to investigate molecular changes involved in wine fermentation while electronic nose and electronic tongue can be applied to detect the evolution of taste and aroma profile. Moreover, as demonstrated through the modeling of NIR, MIR, electronic nose and electronic tongue data, these non destructive methods are suitable for the monitoring of must-wine fermentation giving crucial information about the quality of the final product in agreement with chemical parameters. Although in this study the measurements were carried out in off-line mode, in future these non destructive techniques could be valid and simple tools, able to provide in-time information about the fermentation process and to assure the quality of wine.
The shelf life of Crescenza, a traditional Italian soft cheese, was measured using classical analysis and a commercial electronic nose. Two lots of samples directly supplied by a manufacturer at the ...beginning of their commercial life were stored at 2 constant temperatures (8 and 15°C) and analyzed until their respective expiration dates. Among the physicochemical parameters, pH, acidity, hue, and apparent yield rheological index appeared to be the best predictors of the quality decay. Changes in these indices were described with a sigmoidal transition function allowing definition of a loose and a severe shelf-life protocol, based on the trend of first and second time derivatives. A time range of 1 to 3 d at 15°C and 4 to 8 d at 8°C was accordingly assessed to maintain the freshness of Crescenza cheese. The quality decay of cheese aroma was evaluated by inspecting the headspace fingerprint of the same set of samples using the electronic nose. Sample classification through the aroma fingerprint confirmed the predicted shelf-life time ranges. A clear discrimination between “fresh,” “aged,” and “very aged” samples was obtained using principal components analysis, cluster analysis, and linear discriminant analysis statistical techniques. The predictive ability of the linear discriminant analysis classification model was confirmed by considering a new set of cheese samples purchased at the beginning of their commercial life from a local market and analyzed until their expiration date.
Retrogradation of gelatinised starch is the main phenomenon that influences the texture of cooked rice. The rate of retrogradation is affected by several factors including amylose and amylopectin ...ratio, protein and fibre. The objective of this study was to analyse the pasting properties and the retrogradation behaviour of six traditional and five aromatic Italian rice varieties. The pasted gels, after cooling, were evaluated by dynamic rheological measurements for up to 7
days of storage at 4
°C. The samples were also analysed by a NIR spectrometer. The pasting properties and the retrogradation behaviour of milled rice flours strongly depended on the rice varieties. During gel ageing, a noticeable increase of
G′ and
G″ was observed only for the milled rice varieties Asia, Gange, Fragrance and Vialone Nano, characterised by a high amylose content. No further hardening was found either for the other milled varieties or for all the brown samples. The methods used in this work (dynamic oscillatory rheometry and FT-NIR spectroscopy) turned out to be very useful in the definition of rice starch gels ageing.
Background and aims: Hepatic stellate cells (HSC) are activated by liver injury to become proliferative fibrogenic myofibroblasts. This process may be regulated by the sympathetic nervous system ...(SNS) but the mechanisms involved are unclear. Methods: We studied cultured HSC and intact mice with liver injury to test the hypothesis that HSC respond to and produce SNS neurotransmitters to promote fibrogenesis. Results: HSC expressed adrenoceptors, catecholamine biosynthetic enzymes, released norepinephrine (NE), and were growth inhibited by α- and β-adrenoceptor antagonists. HSC from dopamine β-hydroxylase deficient (Dbh−/−) mice, which cannot make NE, grew poorly in culture and were rescued by NE. Inhibitor studies demonstrated that this effect was mediated via G protein coupled adrenoceptors, mitogen activated kinases, and phosphatidylinositol 3-kinase. Injury related fibrogenic responses were inhibited in Dbh−/− mice, as evidenced by reduced hepatic accumulation of α-smooth muscle actin+ve HSC and decreased induction of transforming growth factor β1 (TGF-β1) and collagen. Treatment with isoprenaline rescued HSC activation. HSC were also reduced in leptin deficient ob/ob mice which have reduced NE levels and are resistant to hepatic fibrosis. Treating ob/ob mice with NE induced HSC proliferation, upregulated hepatic TGF-β1 and collagen, and increased liver fibrosis. Conclusions: HSC are hepatic neuroglia that produce and respond to SNS neurotransmitters to promote hepatic fibrosis.
Spectral resolution (R) and number of repeated scans (S) have a significant effect on the S/N ratio of Fourier transform-near infrared (FT-NIR) spectra, but the optimal values of these two parameters ...have to be determined empirically for a specific problem, considering separately both the nature of the analysed matrix and the specific instrumental setup. To achieve this aim, the instrumental noise of replicated FT-NIR spectra of wheat samples was modelled as a function of R and S by means of the Doehlert design. The noise amounts in correspondence to different experimental conditions were estimated by analysing the variance signals derived from replicate measurements with two different signal processing tools, Savitzky-Golay (SG) filtering and fast wavelet transform (FWT), in order to separate the “pure” instrumental noise from other variability sources, which are essentially connected to sample inhomogeneity. Results confirmed that R and S values leading to minimum instrumental noise can vary considerably depending on the type of analysed food matrix and on the different instrumental setups, and helped in the selection of the optimal measuring conditions for the subsequent acquisition of a wide spectral dataset.
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