Quince Slices Research Articles

Drying of Quince Slices: Effect of Pretreatments on Drying and Rehydration Characteristics

The effect of pretreatments on drying characteristics of quince slices was investigated in a cabinet dryer. The experiments were conducted on quince slices with a thickness of 5 mm at 50°C, 57°C, 64°C, and 71°C with an air velocity of 2.0 m/s. Prior to drying, quince slices were pretreated with citric acid solution or blanched in hot water. Also, the untreated samples were dried as control. The shortest drying time was obtained with quince pretreated with citric acid solution. It was also observed that the rehydration ratio was higher in blanched slices than others. The drying data for the moisture ratio over time was fitted to three thin-layer models with the best performances coming from the Page model. The values of effective moisture diffusivity were found to range between 6.97 × 10−11 and 2.38 × 10−10 m2/s, with activation energy of 29.08–43.01 kJ/mol for quince slices.

Case studies on the effect of the air drying conditions on the convective drying of quinces

The objective of the current study is to examine experimentally the thin-layer drying behavior of quince slices as a function of drying conditions. In a laboratory thermal convective dryer, experiments were conducted at air temperatures of 40, 50 and 60°C and average air velocities of 1, 2 and 3ms−1. Increasing temperature and velocity resulted to a decrease of the total time of drying. The experimental data in terms of moisture ratio were fitted with three state-of-the-art thin-layer drying models. In the ranges measured, the values of the effective moisture diffusivity (Deff) were obtained between 2.67×10−10 and 8.17×10−10m2s−1. The activation energy (Eα) varied between 36.99 and 42.59kJmol−1.

Effects of Pectin-CMC-Based Coating and Osmotic Dehydration Pretreatments on Microstructure and Texture of the Hot-Air Dried Quince Slices

The optimization of osmotic solutions, during dehydration of quince, was investigated by the response surface methodology. The results showed that fructose concentration had the most important effect on water loss and the solution containing fructose 47.68%, calcium chloride 3.99% and citric acid 3.49% was determined as the optimum osmotic solution. Next, the quince slices were pretreated by pectin-carboxymethyl-cellulose-based edible coating and osmotic dehydration and was then hot-air dried. The scanning electron microscopy images showed that the coating and osmotic dehydration decreased and increased collapse in porous structure, respectively. The results of the compression test showed that the both pretreatments caused a decrease in the hardness, which could be attributed to the plasticizing effect of low molecular ingredients, which were absorbed from the coating and osmotic solutions. Both the coated and osmotic dehydrated samples showed lower rehydration ratio than non-pretreated samples. Practical Applications Osmotic dehydration is a gentle drying method, which has received considerable attention because of its low processing temperature and low energy requirement. Moreover, the main advantages of this process are potentially better color, texture and flavor retention along with minimum heat damage. Partially dehydrated fruits and vegetables prepared by osmotic dehydration can be added to foods such as desserts, yogurt, ice cream, confectionery and bakery products. After additional drying, they can also be used as components of cereals or snacks for direct consumption. Dried quince can as ingredient of traditional Iranian food such as quince Khoresh and Chowder. So that in this research, optimization of the osmotic solution formulation was studied for dehydration of quince slices and also effect of edible coating and osmotic dehydration pretreatments were investigated on improvement of the microstructural properties and rehydration characteristics of dried quince slices.

Multi-Objective Optimization of Osmotic–Ultrasonic Pretreatments and Hot-Air Drying of Quince Using Response Surface Methodology

In this study, application of a multi-objective optimization technique based on response surface methodology has been presented. Quince slices were dehydrated using osmotic dehydration with sucrose solutions at different concentration (40 and 60 Brix), processing time (1, 1.5, and 2 h), and ultrasonication time (0, 15, and 30 min) were the factors investigated with respect to water loss, solid gain, and weight reduction. Response surface methodology was used to determine the optimum processing conditions that yield maximum water loss and weight reduction and minimum solid gain during osmotic dehydration of quinces. Dehydrated quince slices at optimized osmo-ultrasound condition were then subjected to air-drying at 60 and 80 °C. Rehydration ratio, shrinkage, and moisture content of dried samples were regarded as responses to the non-thermal and air-drying conditions. Multi-objective optimization led to obtaining the best condition for production of dried quince slices with lowest moisture content, and shrinkage.

An experimental study on the drying kinetics of quince

In this experimental study, drying kinetics of quince slices was investigated as a function of drying conditions. Experiments were conducted using air temperatures of 35, 45 and 55 °C, mean velocities of 0.2, 0.4 and 0.6 m/s and, relative humidity values of 40, 55 and 70%. The experimental moisture data were fitted to some models (namely Henderson and Pabis, Lewis and two-term exponential models) available in the literature, and a good agreement was observed. In the ranges covered, the values of the effective moisture diffusivity, D eff were obtained between 0.65×10 −10 and 6.92×10 −10 m 2/s from the Fick's diffusion model. Using D eff, the value of activation energy ( E a) was determined assuming the Arrhenius-type temperature relationship, which varied from 33.83 to 41.52 kJ/mol. Finally, the sorption isotherms of the dried quince slices were determined.