Effect of different drying technologies on the characteristics and quality of lemon slices

Abstract

This experiment aimed to investigate the effects of four drying methods, namely, hot air drying (HAD), microwave drying (MD), vacuum drying (VD), and microwave vacuum drying (MVD), on the quality of lemon slices.The relevant indicators, including total phenolic content, ascorbic acid content, browning, color, reducing sugar content, volatile component measurements, and principal component analysis of 0 and 30 days storage, were compared after exposure to the four drying methods. The shortest time of 64 min was used to treat the lemon slices via MVD at 1 KW. These samples displayed the least damage after drying and the highest rehydration ratio of 4.12. The contents of VC, reducing sugars, and total phenols of MVD samples were significantly higher than those in the HAD, VD, and MD groups, retaining 105.94 mg/100 g, 21.35 g/100 g, and 77.81 mg GAE/g, respectively, while their color difference values were also the smallest, with a browning degree of 3.55, significantly lower than those in the other treatment groups (p < 0.05), and the degree of browning of the samples in the HAD treatment group was the most serious; in terms of volatile flavor substances, the lemon slice samples in the MVD and HAD treatment groups were more diverse and of better quality. The order of product sensory evaluation was: MVD > VD > HAD > MD. The final scores after comprehensive analysis revealed the order of the four drying methods as MVD, HAD, VD, and MD. Therefore, MVD had a better effect on the sensory perception and nutritional properties of the lemon slices, providing a useful alternative to the conventional drying method.

Low-Pressure Plasma Treatment Increased the Quality and Characteristic Flavor of Lyophilized Lemon Slices

“…Tese results show that olefns (limonene accounted for 51.58% of the total) are the main aroma substances found in lemons, followed by ketones, alcohols, and aldehydes with lower proportions. Te detected volatile substances were lower than in previous studies of lemon slices subjected to diferent drying methods [32], probably due to the diferent processing or the diferent sources of lemon. As some individual compounds presented at diferent concentrations, several signals or spots were generated which represent the formation of corresponding dimers [36].…”

“…It was found in Figure 2(d) that the total phenol content was 1.74 mg/mL in G1, 1.33 mg/mL in G2, and 1.68 mg/mL in G3. Vc and phenols are reported to be chemically unstable and easily decomposed when exposed to heat, light, and oxygen [32]. Terefore, the phenol and Vc contents in the fresh samples (G1) were higher than that of samples stored for 7 d (G2).…”

Dynamic Changes in Volatile Flavor Compounds, Amino Acids, Organic Acids, and Soluble Sugars in Lemon Juice Vesicles during Freeze-Drying and Hot-Air Drying

“…Chen et al confirmed that drying lemon slices using a closed-type solar dryer presented a better performance than using the hot air-dried ones [ 7 ]. Xu et al compared the effects of four drying methods, namely, hot-air drying (AD), microwave drying, vacuum drying, and microwave vacuum drying, on the quality of lemon slices, and found that microwave vacuum drying had a better effect on the sensory perception and nutritional properties of the lemon slices [ 8 ]. Salehi et al investigated the modeling of moisture loss kinetics and color changes on the surface of lemon slices during combined infrared-vacuum drying [ 9 ].…”

Evaluating How Different Drying Techniques Change the Structure and Physicochemical and Flavor Properties of Gastrodia elata

“…Together, this implies that the MVD method can better reduce the influence of temperature with chromaticity. Xu et al [31] also found a similar result using MVD, which was carried out in with light avoidance and vacuum conditions. They also found that, to a certain extent, MVD can reduce the color loss of lemon slices with minimum color-difference values.…”