Edible coating of walnuts and pine nuts by whey protein isolate, pea starch, and carnauba wax reduced the oxidative and hydrolytic rancidity of the nuts and improved sensory characteristics.

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The dielectric (DE) properties, specifically the DE constant (ε') and loss factor (ε''), were measured for vacuum-dried and freeze-dried potato samples at a microwave frequency of 2.45 GHz over a range of different moisture contents (MCs) using a DE probe and also a 2-probe electrochemical impedance spectroscopy (EIS). Third-order polynomial models (ε' = f₁(MC); and ε'' = f₂(MC)) at room temperature were developed for regression analysis. Additionally, at various temperatures (T), biphasic 3rd-order polynomial models (ε' = f₁(MC, T); and ε'' = f₂(MC, T)) were obtained to determine ε' and ε'' as a function of MC and T using measured data. The vacuum-dried potato sample showed a good fitness of ε' and ε'' (R² = 0.95 and 0.96, respectively) to the regression model with the range of MCs from 18% to 80% (w/w), while the freeze-dried potato sample showed a good fitness of ε' and ε'' to the 1st-phase regression model with MC < 50% w/w (R² = 0.95 and 0.96, respectively) and the 2nd-phase regression model with MC > 50% w/w (R² = 0.94 to 0.96). EIS measurements were also used to obtain correlation impedances for ε' and ε'' determined by the DE probe method. The resulted regression analysis meets the demands for simple, rapid, and accurate assessment for transient values of ε' and ε'' of food products during dehydration/drying processes. The EIS method was verified to be a successful alternative to direct measurements of ε' and ε''.

SPostharvest methods for microbial decontamination of fresh produce are limited, and chemical treatment is less popular with growing concerns over toxic residues. A photothermal guiding system was developed with a pulsed-CO2 laser and adjustable two-ZnSe lens beam expander. The system was optimized to ensure uniform radiation of the sample with respect to pulse width (PW) and repetition time (RT) without damaging the food samples. Conjugated gold nanoparticles (GNPs) added to fruit surfaces tested the selective photothermal nanotherapy under laser radiation for enhancing treatment.Apple peel samples (1 cm 2 ) contaminated with Escherichia coli K12 were treated at varying PW and RT for 60, 120 and 180 s. Inactivation of E. coli K12 significantly (P < 0.05) increased as the PW increased at constant RT. Also, the inactivation increased as both RT decreased and PW increased, and with the addition of the GNP. Scanning electron microscopy analysis showed structural damage of E. coli and GNP with minimal damage to fruit surfaces.