This study assessed effects of intrinsic factors, composition and candy size, and extrinsic factors, storage temperature, and humidity, on moisture sorption characteristics of hard candy. Nine types of plain hard candy with various percentage of sucrose (45.0 to 65.0% wt/wt) and citric acid (0.0 to 1.0% wt/wt) were prepared. The prepared samples had surface area per weight ratio (SA/W) of 2.05 to 3.69 cm2/g. Moisture sorption isotherms of all candy formulations were built at 25 °C and 35 °C and were well‐represented by Guggenheim‐Anderson‐de Boer (GAB) model (R2 between 0.9634 and 0.9960). Compositions and SA/W significantly affected moisture sorption characteristics of hard candies. Increasing citric acid content increased rate of moisture uptake, while increasing SA/W decreased absorption rate. Additionally, the predictive models for rate of moisture uptake of candies with different compositions and SA/W at 25 °C and 35 °C and 75% relative humidity based on second‐order response surface methodology were developed and validated. Practical applications Moisture sorption isotherms built and the obtained models of moisture uptake could be used as a guideline to predict moisture sorption characteristics or to estimate shelf life of hard candies, with known compositions and/or storage conditions.

The mass transfer profile (permeability, diffusion, and solubility coefficients) of chlorine dioxide (ClO 2 ), a strong oxidizing agent that is used in food and pharmaceutical packaging, was determined through various common polymeric packaging materials. A continuous system for measuring permeation of ClO 2 , using an electrochemical detector, was developed. It was observed that biaxially-oriented poly(propylene), poly (ethylene terephthalate), poly(lactic acid), nylon, and a multilayer structure of ethylene vinyl acetate and ethylene vinyl alcohol were better barriers for gaseous ClO 2 , as compared to polyethylene, poly(vinyl chloride), and polystyrene. The activation energies of permeation for ClO 2 through poly(ethylene terephthalate) and poly(lactic acid) were determined to be 51.05 AE 4.35 and 129.03 AE 2.82 kJ/mol, respectively. V

Summary The aim of this study was to investigate the effects of gas level and treatment condition on antimicrobial efficacy of ClO2 gas against Salmonella enterica Typhimurium on grape tomato (Lycopersicon esculentum). Grape tomatoes were dip‐inoculated with inoculum of S. enterica Typhimurium TISTR 292 (ATCC 13311) (9.79 ± 0.39 log CFU mL−1) and allowed to dry before treatments. The pre‐inoculated samples were exposed to 0.15–0.85 mg of ClO2 gas, for up to 58 min. The treatments at 4 and 25 °C resulted in population reductions of S. enterica Typhimurium of up to 3.95 ± 0.22 and 7.37 ± 0.39 log CFU per fruit, respectively. The population reduction results were used to construct statistical models to predict efficacy of ClO2 gas. The second‐order equations for treatments at 4 and 25 °C had R2 of 0.87 and 0.95, respectively, and indicated that efficacy of ClO2 gas was significantly influenced by ClO2 gas level, exposure time and treatment temperature.

The effects of gaseous chlorine dioxide (ClO 2 ) on properties and performance of 10 selected polymeric packaging materials, including polyethylene (PE), biaxially oriented poly(propylene), polystyrene, poly(vinyl chloride), poly(ethylene terephthalate) (PET), poly(lactic acid), nylon, and a multilayer structure of ethylene vinyl acetate (EVA)/ethylene vinyl alcohol (EVOH), were evaluated. Physical, mechanical, barrier, and color properties as well as infrared (IR) spectra were assessed before and after polymer samples were exposed to 3600 ppmV ClO 2 gas at 23 C for 24, 168, and 336 h. The IR spectra of the ClO 2 -treated samples revealed many changes in their chemical characteristics, such as the formation of polar groups in the polyolefin, changes in functional groups, main chain scission degradation, and possible chlorination of several materials. The ClO 2 -treated PE samples showed a decrease in tensile properties compared with the untreated (control) films. Decreases in moisture, oxygen, and/or carbon dioxide barrier properties were observed in the treated PE, PET, and multilayer EVA/EVOH/EVA samples. A significant increase (P < 0.05) in the barrier to O 2 was observed in the ClO 2 -treated nylon, possibly the result of molecular reordering, which was found through an increase in the crystallinity of the material.

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