Near-infrared spectroscopy as a rapid method for evaluation physicochemical changes of stored soybeans

Storage conditions of grains affect compositional characteristics. Determination of these characteristics is time-demanding and requires analytical methods. The objective of the study was to investigate the potential application of near-infrared (NIR) spectroscopy technique as a process analytical technology (PAT) for quality assessment of soybeans (BRS 284 cultivar) stored under different conditions (25 and 35 °C) for 9 months. In addition, NIR spectral information of BRS 284 was compared with other cultivar (BRS 232) in order to verify its potential to discriminate these samples. Chemical composition, pH, free fatty acid content and color were determined by traditional methods. NIR spectral information in the wavelength range of 400–2500 nm were obtained from the stored soybean. Principal component analysis (PCA) was applied as an exploratory tool of spectral data. Loadings of the first 3 principal components were used to identify most important wavelengths influencing the spectra. At 25 °C, soybeans exhibited little or no significant changes in physicochemical properties; on the other hand, at 35 °C, there was a reduction on color and pH and increase on acidity. PCA scores of first 2 principal components showed that none of the spectral pre-processing treatment (SNV, 1st and 2nd derivative) provided discrimination between soybeans cultivars and detection of physicochemical changes of stored soybean. Results have shown the potential application of NIR spectroscopy as a PAT for rapid assessment of quality changes of stored soybean7316CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO ARAUCÁRIA DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO ESTADO DO PARANÁ - FA473117/2013-4160/201

Optimization of ultrasound‐assisted extraction of grape‐seed oil to enhance process yield and minimize free radical formation

Grape seeds are a relatively abundant source of oil and bioactive compounds. To use this byproduct, the current work aimed to optimize the ultrasound‐assisted extraction (UAE) of grape‐seed oil to obtain greater process yield and minimize free radical formation in the oil. RESULTS The optimal condition was 15 °C with an ultrasonic wave amplitude of 42 µm, leading to a process yield of 82.9% and content of free radicals of 14.7 × 1017 kg−1 and 3.4 × 1018 kg−1 for samples stored for 7 and 30 days, respectively. No significant differences in fatty acid composition and acidity and iodine values were observed between samples. The oil obtained by ultrasound had greater phenolic compound content and antioxidant activity by ferric reduction than the control sample (without ultrasound application). However, higher content of free radicals and peroxide value was observed. CONCLUSION Sonication improved extraction yield when compared to the process without ultrasound application. Moreover, UAE favored the extraction of phenolic compounds. As it enhanced process yield with the minimum formation of free radicals, UAE is a promising oil‐extraction technology981350195026CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESSem informaçãoSem informaçã

Kinetic modeling of the conversion and losses of isoflavones during soybean soaking

The objective of this study was to solve the first-order kinetic models of interconversion and losses of isoflavones, expressed as differential equations, by Laplace transform method. The kinetic models were applied to investigate the changes in the contents of different forms of isoflavone (malonylglucosides, β-glucosides, and aglycones) during soybean soaking at various temperatures (25 °C, 40 °C, 55 °C, and 70 °C). Soaking at 25 °C did not influence the contents of isoflavones of the daidzein, glycitein, and genistein series. A higher hydrolysis rate constant, which corresponds to the conversion of β-glucosides to aglycones, was observed at 55 °C due to the action of endogenous β-glucosidase. However, at 70 °C, there was a decrease in the hydrolysis rate. All isoflavone forms of the genistein and daidzein series were thermally stable during soybean soaking at 70 °C. A mathematical modelling of the kinetics provided better insights into the mechanisms of interconversion and losses of the isoflavones261171177CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFSL, CLH, MSF, and DR would like to thank CNPq and CAPES for graduate scholarships; LEK and EII are CNPq Research Fellow

Isotermas de dessorção de filé de bonito (Sarda sarda) desidratado osmoticamente e defumado Desorption isotherms of osmotically dehydrated and smoked Atlantic bonito (Sarda sarda) fillets

O presente trabalho teve como objetivo a obtenção de isotermas de dessorção de filés de bonito (Sarda sarda), previamente salgados a vácuo e defumados com fumaça líquida. As isotermas foram obtidas a quatro temperaturas (5, 25, 40 e 60 ºC) em condições de dessorção, através do método gravimétrico estático, com soluções salinas saturadas. Os dados experimentais foram ajustados a quatro modelos da literatura (BET linearizado, GAB, Henderson e Oswin modificado). Os resultados mostraram que as isotermas tomaram forma sigmoidal de tipo II e que o modelo de Guggenheim-Anderson-deBoer (GAB) foi aceitável para modelar os dados experimentais. O calor isostérico de dessorção, um parâmetro necessário para simular e projetar adequadamente o secador, também foi calculado e pode ser representado através de um modelo matemático simples, em função da umidade de equilíbrio.<br>The main objetive of this work was to obtain the desorption isotherms of Atlantic bonito (Sarda sarda) fillets, previously subjected to an immersion impregnation process with NaCl solutions and smoked in liquid smoke. The isotherms were obtained at four temperatures (5, 25, 40 and 60 ºC), using the static method with saturated salt solutions. The experimental data were fitted to four models (linearized BET, GAB, Henderson and modified Oswin). The results showed that a type II sigmoidal isotherm, with GAB equation, gave the best fit. The isosteric heat of desorption was also calculated and a simple empirical equation has been proposed to represent this heat, as a function of equilibrium moisture content