Abstract

Citrus peels are considered as an agricultural waste with negative environmental impacts. In the present study, yellow (ripe) and green (unripe) Citrus reticulata peels were dried in a hot air impingement dryer and the effect of drying temperatures (40, 50, 60, and 70 °C) on the drying characteristics, volatile compounds, and antioxidant capacity were explored. The results showed that the drying time of samples was reduced by more than 50% when the drying temperature was increased from 40 to 70 °C. A total of 56 peaks and 29 volatile components were identified by headspace-gas chromatography-ion mobility spectrometry. Drying caused an obvious reduction in the concentration of linalool oxide, benzaldehyde, (E)-2-heptenal, and 1-pentanol, and an increment in the concentration of pentanal, decanal, linalool, and (E)-2-hexenol. Principal component analysis showed that samples under different treatments were clearly distinguished. Drying resulted in a significant reduction of 2,2‐diphenyl‐1‐picrylhydrazyl and ferric reducing antioxidant power. These findings will contribute to a better understanding of citrus peel drying as well as their volatile profiles and antioxidant capacity changes during drying.

摘要

柑橘皮被认为是对环境有负面影响的农业废弃物。在本研究中，黄色（成熟）和绿色（未成熟）Citrus reticulata果皮在热空气冲击式干燥机中干燥，并探讨了干燥温度（40、50、60 和 70 °C）对干燥特性、挥发性化合物和抗氧化能力的影响。结果表明，当干燥温度从40℃提高到70℃时，样品的干燥时间减少了50%以上。顶空-气相色谱-离子淌度谱共鉴定出56个峰和29个挥发性成分。干燥导致氧化芳樟醇、苯甲醛、(E)-2-庚烯醛和1-戊醇的浓度明显降低，而戊醛、癸醛、芳樟醇和(E)-2-己烯醇的浓度增加。主成分分析表明，不同处理下的样品明显区分。干燥导致显着减少2，2-二苯基-1-苦基肼和铁降低抗氧化能力。这些发现将有助于更好地了解柑橘皮干燥过程中的挥发性特征和抗氧化能力的变化。