Adnan Bozdogan

Improving the screening of potato breeding lines for specific nutritional traits using portable mid-infrared spectroscopy and multivariate analysis

Efficient selection of potato varieties with enhanced nutritional quality requires simple, accurate and cost effective assays to obtain tuber chemical composition information. In this study, 75 Andean native potato samples from 7 Solanum species with different colors were characterized and quantified for their anthocyanin, phenolics and sugar content using traditional reference methods. IR (infrared) spectra of potato extracts were collected using a portable infrared system and partial least squares regression (PLSR) calibration models were developed. These models were validated using both full cross-validation and an independent sample set giving strong linear correlation coefficients of prediction (rPred)>0.91 and standard error of prediction (SEP) of 24mg/100g phenolics, 7mg/100g monomeric anthocyanins, 0.1g/100g reducing sugars and 0.12g/100g sucrose. Overall, portable infrared system with PLSR showed great potential to facilitate potato breeding and certain aspects of crop management, material selection for potato processing and related research by providing alternative prediction models.

Viscosity behavior of bitter orange (Citrus aurantium) juice as affected by temperature and concentration

The rheological properties of different concentrations (29.3–49.0°Brix) of bitter orange (Citrus aurantium) juice concentrate were evaluated using a viscometer at different temperatures (10–50°C). Samples showed Newtonian behavior. The effects of concentration and temperature on apparent viscosity of sample were significant (P < 0.01). Activation energy value (11.16–34.35 kJ/mol) increased with concentration. The exponential and quadratic models adequately described the effect of concentration on viscosity of bitter orange juice concentrate. To conclude, a single equation was proposed to show the combined effect of concentration and temperature.