A novel free PhotoMetrix UVC is proposed for both the operation of a universal serial bus video camera (UVC) and multivariate image analysis, allowing a full solution for point-of-use analysis. A UVC was placed in an open-source 3D-printed chamber illuminated by a white light-emitting diode (LED) with controlled intensity of light. The digital images captured were converted into red, green, and blue (RGB) histograms, and regression models were used within the app. As a proof-of-concept, four adulterants in raw milk samples were determined. The coefficient of determination (R2Cal) for all models was higher than 0.99, and no significant differences (p < 0.05) between the measured and predicted values were identified. The root mean square error of calibration (RMSEC) and root mean square error of cross validation (RMSECV) were satisfactory, with values less than 0.1 and 0.7 g L-1, respectively. The recoveries ranged from 90 to 120% in spiked milk samples, and partial least square (PLS) models showed root mean square error of prediction (RMSEP) of 0.28, 0.33, 0.48 and 0.39 g L-1 for chloride, hypochlorite, hydrogen peroxide and starch, respectively. The PhotoMetrix UVC app was feasible for the colorimetric chemical analysis using a smartphone improving the applicability, mobility, and usability.

RESUMO Atualmente o Rio Grande do Sul é o principal estado produtor de mirtilo no Brasil. Praticamente toda produção é comercializada in natura, com pouca quantidade destinada ao processamento. A produção de fermentado alcoólico de mirtilo é uma alternativa para ampliar a indústria de bebidas e oferecer ao consumidor um produto de valor agregado, bem como um novo mercado para os produtores brasileiros de mirtilo. Os objetivos deste estudo foram produzir fermentados alcoólicos de mirtilo, avaliar o efeito da desacidificação (com carbonato de cálcio) e da chaptalização (com xarope de glicose e sacarose) sobre as características físico-químicas, teor de antioxidantes e parâmetros sensoriais. As amostras foram avaliadas quanto ao teor de sólidos solúveis totais, pH, acidez total titulável, açúcares totais, graduação alcoólica, antocianinas monoméricas e totais, flavonóis totais, compostos fenólicos totais e atividade antioxidante pelos métodos DPPH e FRAP. O uso de carbonato de cálcio causou a redução da acidez total enquanto o uso de xarope de glicose resultou em fermentados de baixo teor alcoólico. Os fermentados de mirtilo das cultivares Climax e Aliceblue apresentaram maior conteúdo de antocianinas quando produzidos com xarope de glicose. O uso de carbonato de cálcio e xarope de glicose também resultou em fermentados mais apreciados pelos provadores em relação a cor. Quanto ao sabor, os fermentados das cultivares George e Aliceblue que não receberam tratamento foram os menos preferidos sem tratamento (sem adição de carbonato e não chaptalizados). A presença de compostos fenólicos pode ter influenciado positivamente o sabor dos fermentados, uma vez que os fermentados mais preferidos apresentaram maior conteúdo desses compostos.

ABSTRACT Currently, Rio Grande do Sul state is the main producer of blueberry in Brazil. Practically all production is commercialized in fresh state and only a small portion is subject to processing. The blueberry wine making process is an alternative to expand the beverage industry and offers to the consumer a value-added product as well as a new market for Brazilian blueberry producers. The objectives of this study were to produce wines from blueberries and to evaluate the effect of deacidification (with calcium carbonate) and chaptalization (with glucose syrup or sucrose) on physicochemical characteristics, antioxidant content, and sensory parameters. Samples were analyzed for total soluble solids, pH, total titratable acidity, total sugar content, alcohol content, monomeric and total anthocyanin, total flavonols, total phenolic compounds and antioxidant activity by DPPH and FRAP methods. The use of calcium carbonate caused a reduction in total titratable acidity, while the use of glucose syrup resulted in wines with low alcohol content. The blueberries wine from Climax and Aliceblue cultivars had higher content of anthocyanin when produced with glucose syrup. The use of calcium carbonate and glucose syrup also provided wines more appreciated by tasters in relation to color. With regard to flavor, George and Aliceblue were the cultivars with lower preference under the control treatments (without carbonate and sugar). The presence of phenolic compounds may have provided a positive influence on wine flavor, once the more preferred wines presented the greater phenolic content.