The main goal of this study was to investigate the analytical performances of a state-of-the-art device, one of the smallest dispersion NIR spectrometers on the market (MicroNIR 1700), making a critical comparison with a benchtop FT-NIR spectrometer in the evaluation of the prediction accuracy. In particular, the aim of this study was to estimate in a non-destructive manner, titratable acidity and ascorbic acid content in acerola fruit during ripening, in a view of direct applicability in field of this new miniaturised handheld device. Acerola (Malpighia emarginata DC.) is a super-fruit characterised by a considerable amount of ascorbic acid, ranging from 1.0% to 4.5%. However, during ripening, acerola colour changes and the fruit may lose as much as half of its ascorbic acid content. Because the variability of chemical parameters followed a non-strictly linear profile, two different regression algorithms were compared: PLS and SVM. Regression models obtained with Micro-NIR spectra give better results using SVM algorithm, for both ascorbic acid and titratable acidity estimation. FT-NIR data give comparable results using both SVM and PLS algorithms, with lower errors for SVM regression. The prediction ability of the two instruments was statistically compared using the Passing-Bablok regression algorithm; the outcomes are critically discussed together with the regression models, showing the suitability of the portable Micro-NIR for in field monitoring of chemical parameters of interest in acerola fruits.

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Wines produced from non-Vitis vinifera varieties have great economic importance in Brazil and represent more than 80% of the national production, but scientific information regarding the quality of these wines is rare. The objective of this research was to determine consumer acceptability, the sensory profile and the chemical composition of the most consumed Brazilian red wines produced with Vitis labrusca and promising hybrid varieties, identifying the parameters that drive the preference of consumers. Commercial wines collected directly from different wineries were evaluated regarding their overall acceptance by 120 consumers. Twelve trained panelists developed the sensory profile of the wines using Quantitative Descriptive Analysis (QDA). Physicochemical analyses carried out to determine the pH, titratable and volatile acidity, total solids, alcohol degree, total phenolics, free SO 2 and the reducing sugar contents of the wines. The data was analyzed by ANOVA, Tukey test, Internal Preference Mapping (MDPREF), Cluster analysis, Principal Component Analysis (PCA), Partial Least Square regression (PLS), and Extended Internal Preference Map (EPM). In general wines produced from Ives (V. labrusca) grape showed higher aroma/flavor notes described as sweet, grape, grape juice, blackberry and roses. The wines produced from the hybrid grape Máximo differed from those elaborated with the variety Ives, especially due to their higher intensity of earthy/mushroom, vegetative/green beans, woody and yeast sensory notes. The PLS and EPM analyses indicated that fruity notes associated with the aroma and flavor of grape and grape juice were sensory drivers of Brazilian consumers' preference. On the other hand, the majority of the consumers did not like the sensory notes described as earthy/mushroom, vegetative/green beans and yeast found in the wines produced from Máximo. The wine elaborated exclusively with the hybrid Seibel 2 and the wine containing the V. labrusca grapes Ives and Isabella were preferred by the majority of the consumers and only a minor segment of consumers appreciated the wines elaborated solely with Máximo grape. Thus the hybrid grape Seibel 2 and the recently developed hybrid Máximo were shown to be promising varieties for the winemaking of quality wines in Brazilian regions where the environmental conditions are not good for the cultivation of V. vinifera varieties.

Concentrating cashew apple juice alters the beverage aroma and flavor, compromising consumer acceptability of the concentrated beverage. To understand the mechanisms involved in these changes, this research characterized the dynamics of the loss and emergence of volatile compounds during cashew apple juice concentration, reporting their impact on beverage sensory quality. Fresh cashew apple juice (10.3°Brix) was concentrated in a thermal-siphon type evaporator operating in a closed system. Five samples were taken throughout the concentration process with the following soluble solids contents: 11.8°Brix, 14.9°Brix, 20.2°Brix, 29.6°Brix and 42.1°Brix. Trained judges rated the aroma note intensities, described as "fresh cashew apple" and "cooked" as perceived in the fresh and concentrated beverages. The headspace volatiles of the six samples were identified and quantified by GC-MS. The results indicated the esters as the major component in the fresh juice (226.46 μg kg −1 ) representing 45.0% of the total mass of volatiles, followed by the terpenes (118.98 μg kg −1 ), acids (45.23 μg kg −1 ), aldehydes (39.10 μg kg −1 ), alcohols (18.91 μg kg −1 ), lactones (19.15 μg kg −1 ), hydrocarbons (18.02 μg kg −1 ) and ketones (11.05 μg kg −1 ). Predictive statistical models (R 2 N 0.956, p ≤ 0.002) revealed that on reaching 14.9°Brix, the ester concentration declined more than 90%, the terpene content almost 100%, alcohols 85%, aldehydes 80% and hydrocarbons 90%. At 14.9°Brix, the intensity of "fresh cashew apple" aroma still predominated in the juice, but the panelists detected the presence of a weak "cooked" aroma. Concentration of the beverage to 20.2°Brix or above expressively increased the cooked aroma intensity and the concentration of hydrocarbons, alcohols and some aldehydes usually associated with off-flavors such as pentanal and decanal. This raises the possibility that some of these compounds might have been formed during juice processing. Juice with better sensory quality could possibly be obtained by concentrating the beverage to levels below 20.2°Brix, recovering the esters that evaporated off the juice until~15°Brix is reached, and re-adding them to the juice concentrated.

The study aims at developing a methodology for qualitative mapping of nutraceutical compounds in fruit by near infrared hyperspectral imaging (NIR-HSI), focusing on vitamin C mapping in acerola (Malpighia emarginata D.C.), a Brazilian super-fruit characterised by its high content of ascorbic acid. Despite the fact that the spectral approach has often been applied to agricultural crops, research on acerola is very limited. So far, it is known that ascorbic acid decreases in acerola during ripening, but there is no information about its distribution in the fruit from green to red ripe maturity stages. Towards this aim, hyperspectral images of ten sliced acerola, picked at three maturity stages, were acquired using a SisuChema NIR-HSI system. On the pre-processed images, combined in a comprehensive matrix, principal component analysis was computed to select relevant components for classical least square (CLS) regression. CLS allowed distribution maps of ascorbic acid to be obtained (non-negativity, LOF = 1.9%), using, as reference spectra, acerola juices enriched with 0% and 5% of vitamin C powder. The pixels correlated with 5%-enriched juice showed a reduction from 29% to 6.5% according to colour changes, confirming a vitamin C decrease along the ripening stages. These results demonstrated the reliability of NIR-HSI for the evaluation of vitamin C distribution inside the different acerola areas. The presented approach presents the basis for qualitative mapping of nutraceutical compounds in fruits.Keywords: acerola, vitamin C, near infrared hyperspectral imaging (NIR-HSI), classical least square (CLS) Introduction Acerola (Malpighia emarginata D.C.) is a round-shaped fruit, with diameter varying from 3 cm to 6 cm and a very thin protective peel that quickly ripens and encases its fleshy and succulent pulp. At the initial ripening stage, the fruit has a full green colour, changing to yellow-reddish and finally to red or purple when completely ripened, depending on the genotype. The colour of the fruits is not only a sign of pigment changes, but is also linked to complex biochemical changes occurring during ripening, which involve all its main compounds. Indeed, acerola is rich in many nutrients, such as protein, carotenes, thiamine, riboflavin, niacin, proteins, calcium and phosphorus, but its main appealing feature is related to its high vitamin C content. 1 Vitamin C is the generic term for all compounds exhibiting the biological activity of l-ascorbic acid, 2 including ascorbic acid and dehydroascorbic acid, and is one of the most important nutritional quality factors in many horticultural crops. Vitamin C biological activity is relevant in the development and maintenance of the human body's health status. 3 An intake of 100-200 mg per day has been suggested, since stress in modern life is known to increase the requirement for antioxidant compounds. 2 Vitamin C is a six-carbon keto-lactone, a strong reducing agent, which serves as an antioxidant and as a cofactor in hydroxylation reactions. Hydrogen donation from...

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