Effects of Hot Air Drying on Drying Kinetics and Anthocyanin Degradation of Blood-Flesh Peach

Abstract

The purpose of this study was to explore the drying kinetics, effective moisture diffusivity, activation energy, color variation, and the thermal degradation properties of anthocyanins of blood-flesh peach under hot air drying for the first time. The results showed that the hot air-drying process of blood-flesh peach belongs to reduced-speed drying. The Page model could accurately predict the change of moisture ratio of blood-flesh peach. The effective moisture diffusivity during hot air drying of blood-flesh peach was in the range between 1.62 × 10−10 and 2.84 × 10−10 m2/s, and the activation energy was 25.90 kJ/mol. Fresh samples had the highest content (44.61 ± 4.76 mg/100 g) of total monomeric anthocyanins, and it decreased with the increase of drying temperature. Cyanidin-3-O-glucoside and delphinidin-3-O-galactoside were the main anthocyanins of blood-flesh peach as identified and quantified by UPLC-QqQ-MS. Interestingly, during the drying process, the content of cyanidin-3-O-glucoside increased at the beginning, and then decreased. However, the content of delphinidin-3-O-galactoside kept decreasing during the whole drying process. Considering the drying efficiency, fruit color and quality, 70 °C would be a suitable temperature for drying blood-flesh peach. This research will provide beneficial information for understanding the anthocyanin degradation of blood-flesh peach during drying, and guide the production of high-quality dried products.

Solar and Convective Drying: Modeling, Color, Texture, Total Phenolic Content, and Antioxidant Activity of Peach (Prunus persica (L.) Batsch) Slices

“…On the other hand, in solar drying, the highest drying speeds were observed at an airflow of 3 m/s (0.053 gH 2 O/g d.m min −1 ), observing the influence of the airspeed on drying kinetics [32]. These results were similar to Tan [33]. They reported that the drying speeds of drying Blood-Flesh Peach at 50 • C and 0.5 m/s ranged from 0.04 to 0.1 gH 2 O/g d.m min −1 .…”

“…Azam [32] mentione that the reducing sugars could be susceptible to non-enzymatic browning reactions, an some disaccharides could also hydrolyze during heating. On the other hand, ΔE is the combination of the color change of all three-color pa rameters, and it is widely applied to analyze the color change of dried samples and fo comparison between the initial color of fresh fruit and the final color of final fruit [33]. I this sense, it is important to mention that the early maturity stage of the fresh fruit use for drying processes was of great importance in color parameters; as it was expressed i the previous paragraph, a high content of sugar in the maturity stage could lead to a majo browning production.…”

“…The texture of dried fruits becomes an important quality affecting consumer acceptance and is one of the most important parameters associated with dried snack food [33]. In this sense, the hardness values of dried peach slices by natural convection, forced convection, and solar drying methods are presented in Table 3.…”

Hot Air Drying of Seabuckthorn (Hippophae rhamnoides L.) Berries: Effects of Different Pretreatment Methods on Drying Characteristics and Quality Attributes

“…The moisture ration was calculated as Equation (2) [ 19 ]. where M 0 is the dry basis moisture content of seabuckthorn berries at the initial drying time, M e is the equilibrium of dry basis moisture content, M t is the dry basis moisture content at any time.…”

Combined Pulsed Vacuum Osmotic Dehydration and Convective Air-Drying Process of Jambolan Fruits

“…Tan et al [78] state that drying temperature and time can affect the quality of dried fruits and vegetables. When the drying temperature is too low, enzymatic browning increases, and if the temperature is too high, most of the nutrients can be destroyed.…”