Objectives Colour is amongst the parameter which is used for process control during roasting. Materials and Methods In this study, the effects of hot air roasting temperature (120, 130, 145, 160, and 170°C) and hot air velocity (0.6, 1.3, and 2 m/s) on colour change kinetics of pistachio nuts were investigated by employing image analysis and simultaneously chlorophylls and xanthophylls (lutein and β-carotenoid) concentration were determined by spectrophotometric measurement method. Results We found that roasting temperature and hot air velocity had significant effect on colour changes. There is a correlation between a- and b-value with chlorophylls and xanthophylls concentration, respectively. The roasting temperature was found to be the main factor affecting colour development. The variations in the pigments concentration and colour parameters of pistachio nuts were adequately simulated by quadratic and cubic polynomials. The changes in L-, b-values, and xanthophylls degradation were well-fitted to the first-order kinetic model while a-value and chlorophylls degradation followed the zero-order kinetic. The activation energy was determined at 113.9, 116.7, and 117.2 kJ/mol with R2 ≥ 99.9 and 191, 195, and 163.2 kJ/mol with R2 ≥ 99.5 and 73.7, 71.3, and 81.6 kJ/mol with R2 ≥ 99.9 for L-, b-, and a-value in hot air velocity of 0.6, 1.3, and 2 m/s, respectively. Conclusions Activation energy of chlorophylls and xanthophylls degradation were in the range of the activation energy for the yellowness (b-value) and redness (a-value) reactions.

: Pistachio has high nutritional value and popularity. The susceptibility of pistachio to aflatoxin contamination caused establishing a monitoring system introduced and implemented by the Ministry of Health in Iran to ensure consumers' access to safe and hygienic pistachios. In this research, aflatoxin contamination level in all consignments (7298) exporting to E.U. was examined using HPLC with fluorescence detection after immunoaffinity column clean up from Nov 2012 to Oct 2018. The average recoveries ranged 78.6% - 97.6%, with a relative standard deviation for reproducibility below 8.5% and expanded uncertainty of aflatoxin B1 (AFB1) at spiked levels 1, 4, and 8 ng/g were 0.17, 0.57, 0.89 ng/g, respectively. The results showed that aflatoxin B1 and total (AFT) were detected in 1921 (23.4%) and 1927 cases (23.5%), with the mean values ranging from 2.18 - 4.6 ng/g and 2.8 - 5.1 ng/g during six consecutive years, respectively. Implementing an effective monitoring system for pistachio nuts could determine consignments contaminated with aflatoxins. Concerning AFB1, risk assessments recorded for dietary exposure dose, margin of exposure (MOE), Hazard Index (HI), estimated liver cancer risk, and cancer incidence attributable to dietary ranged 0.0132 - 0.1180 ng/kg.bw/day, 1441 - 12843, 0.21 - 1.84, 0.00071 - 0.00633 cases/105 population/year, 0.02 - 0.2%, respectively. Identification and rejection of contaminated cargos lead to an increase in MOE (> 10000), and it also guarantees that pistachio consumption is safe from a toxicology point of view. Due to the monitoring system, the estimation of liver cancer incidence attributable to dietary AFB1was reduced (≤ 0.02%). It indicates that the consumption of pistachio poses no health risk for Europeans and Iranians.

No abstract